HK1165362A

HK1165362A - Catalyst for the production of ethanol by hydrogenation of acetic acid comprising platinum-tin on silicaceous support

Info

Publication number: HK1165362A
Application number: HK12106304.4A
Authority: HK
Inventors: H．魏纳; V．J．约翰斯顿; J．L．波茨; R．耶夫蒂奇
Original assignee: 国际人造丝公司
Priority date: 2009-10-26
Filing date: 2010-10-26
Publication date: 2012-10-05

Description

Catalyst comprising platinum-tin on a siliceous support for the production of ethanol by hydrogenation of acetic acid

Priority requirement

Priority of us application No 12/588,727 filed on 26/10/2009, this application is incorporated herein by reference in its entirety.

Technical Field

The present invention relates generally to a tunable catalyst for hydrogenating carboxylic acids, particularly acetic acid, and a flexible process for dehydrogenating acetic acid, wherein the ratio of ethanol to ethyl acetate and acetaldehyde may be varied with a variety of catalysts to suit changing commercial conditions. More particularly, the present invention relates to catalysts for the gas phase hydrogenation of carboxylic acids, particularly acetic acid, to produce various products including the corresponding alcohols, esters and aldehydes, particularly ethanol. The catalyst exhibits excellent activity and selectivity in the product range.

Background

There is a long felt need for an economically viable process for converting acetic acid to ethanol that can be used by itself or subsequently converted to ethylene, which is an important commercial feedstock as it can be converted to vinyl acetate and/or ethyl acetate or any of a number of other chemical products. For example, ethylene can also be converted into a number of polymer and monomer products. Fluctuating natural gas and crude oil prices contribute to fluctuating costs of conventionally produced petroleum or natural gas derived ethylene, thereby making the need for alternative sources of ethylene greater than ever as oil prices rise.

Catalytic processes for the reduction of alkanoic acids and other carbonyl-containing compounds have been extensively studied and various combinations of catalysts, supports and operating conditions have been mentioned in the literature. Yokoyama et al, in "Fine chemicals through hydrolysis catalysis. Carboxylicacids and derivitives" reviewed the reduction of various carboxylic acids on metal oxides. Some of the attempts to develop hydrogenation catalysts for various carboxylic acids are outlined in chapter 8.3.1. (Yokoyama, T.; Setoyama, T. "Carboxylic acids and derivatives." in: "Fine chemicals through hydrolysis catalysis." 2001, 370-.

A series of studies by m.a. vannonic et al involved the conversion of acetic acid over various heterogeneous catalysts (Rachmady w.; vannonic, m.a.; j.catal.2002, 207, 317-.

The use of H on loaded and unloaded iron was reported in different studies₂Reducing acetic acid in the gas phase. (Rachmady, W.; Vannice, M.A.J.Catal.2002, 208, 158-169).

In Rachmady, w.; additional information on catalyst surface species and organic intermediates is given in vannaice, m.a., j.catal.2002, 208, 170-.

In Rachmady, w.; vanniece, m.a.j.cat.2002, 209, 87-98 and Rachmady, w.; vapor phase acetic acid hydrogenation over a series of supported Pt-Fe catalysts was further investigated in Vannice, M.A.J.Catal.2000, 192, 322-334.

Various relevant publications relating to the selective hydrogenation of unsaturated aldehydes can be found in: (Djerboua, F.; Benachour, D.; Touroude, R.applied Catalysis A: General 2005, 282, 123-.

Studies reporting the activity and selectivity of cobalt, platinum and tin containing catalysts in the selective hydrogenation of crotonaldehyde to unsaturated alcohols were found in: touroude et al (Djerboua, F.; Benachour, D.; Tourooude, R. applied Catalysis A: General 2005, 282, 123-133 and Liberkova, K.; Tourounde, R.; J. mol. Catal.2002, 180, 221-230) and K.Lazar et al (Lazar, K.; Rhodes, W.D.; Borbarth, I.; Hegedues, M.; Margitfalvi, 1.L. hyperfinenteractions 2002, 1391140, 87-96).

Microresidation measurements, infrared spectroscopy measurements, and reaction kinetics measurements in combination with quantum chemometrics are discussed by m.santiago et al (Santiago, m.a.n.; Sanchez-Castillo, m.a.; Cortright, r.d.; Dumesic, 1, A.J cat.2000, 193, 16-28.).

Catalytic activity for the hydrogenation of acetic acid has also been reported for heterogeneous systems with rhenium and ruthenium. (Ryashentseva, M.A.; Minachev, K.M.; Buiychev, B.M.; Ishchenko, V.M. Bull.Acad Sci.USSR1988, 2436-.

U.S. patent No.5,149,680 to Kitson et al describes a process for the catalytic hydrogenation of carboxylic acids and their anhydrides to alcohols and/or esters using platinum group metal alloy catalysts. U.S. Pat. No.4,777,303 to Kitson et al describes a process for the production of alcohols by the hydrogenation of carboxylic acids. U.S. Pat. No.4,804,791 to Kitson et al describes another process for the production of alcohols by the hydrogenation of carboxylic acids. See also USP 5,061,671; USP 4,990,655; USP 4,985,572; and USP 4,826,795.

Malinowski et al (Bull. Soc. Chim. Belg. (1985), 94(2), 93-5) discuss the heterogenisation of acetic acid on a support material such as silica (SiO. in the case of₂) Or titanium dioxide (TiO)₂) The reaction on the lower valence titanium of (a).

Bimetallic ruthenium-tin/silica catalysts are prepared by reacting tetrabutyltin with ruthenium dioxide supported on silica. (Loessard et al, students in Surface Science and catalysis (1989), Volume Date 1988, 48(struct. read. surf.), 591-.

For example, catalytic reduction of acetic acid has also been studied in Hindermann et al (Hindermann et al, J. chem. Res., Synopses (1980), (11), 373), disclosing catalytic reduction of acetic acid on iron and on base-promoted iron.

Existing approaches suffer from various problems that hinder commercial viability, including: (i) the catalyst does not have the necessary selectivity to ethanol; (ii) the catalyst may be too expensive and/or non-selective for the production of ethanol and produce unwanted by-products; (iii) excess operating temperature and pressure; and/or (iv) insufficient catalyst life.

Summary of The Invention

It has been found that when reducing acetic acid over a platinum tin catalyst dispersed on a modified stabilized siliceous support, wherein the siliceous support comprises an effective amount of a support modifier selected from the group consisting of: (i) alkaline earth metal oxides, (ii) alkali metal oxides, (iii) alkaline earth metal metasilicates, (iv) alkali metal metasilicates, (v) zinc oxide, (vi) zinc metasilicate and (vii) precursors of any of (i) - (vi), and any mixtures of (i) - (vii), high selectivity to ethanol in conversion can be obtained by passing a gaseous stream comprising hydrogen and acetic acid through the catalyst in the vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of from about 125 ℃ to 350 ℃, more preferably from about 225 ℃ to 300 ℃, still more preferably from about 250 ℃ to 300 ℃, when the amount and oxidation state of platinum and tin and the ratio of platinum to tin and the modified stabilized siliceous support are controlled as described herein. In one aspect of the invention, the effects of bronsted acid sites present on the surface of a silicon-containing support having a support modifier selected as described above are counteracted. In another aspect, the above-described support modifier is effective to prevent excessive loss of activity and selectivity of the catalyst at 275 ℃ for a period of up to 168, 336, or even 500 hours in the presence of flowing acetic acid vapor. In another aspect of the invention, when low selectivity to conversion of acetic acid to highly undesirable byproducts such as alkanes is desired, the support modifier is effective to inhibit ethyl acetate production resulting in high selectivity to ethanol production. Preferably, the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, as well as precursors thereof and mixtures of any of the foregoing. The most preferred support modifier is calcium metasilicate.

It has been found that when reducing acetic acid over a platinum tin catalyst dispersed on a substantially basic calcium metasilicate/silica support, wherein a gaseous stream comprising hydrogen and acetic acid is passed through the catalyst in the vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of from about 125 ℃ to 350 ℃, more preferably from about 225 ℃ to 300 ℃, still more preferably from about 250 ℃ to 300 ℃, a high selectivity to ethanol can be obtained in the conversion when the amount and oxidation state of platinum and tin, as well as the ratio of platinum to tin and the acidity of the calcium metasilicate/silica support, are controlled as described herein. In particular, at least 80% of the acetic acid converted is converted to ethanol and less than 4% of the acetic acid is converted to compounds other than compounds selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, and mixtures thereof using the preferred catalysts and processes of the present invention. In a preferred process, platinum is present in an amount of 0.5% to 5% by weight of the catalyst; while tin is present in an amount of at least 0.5 up to 10% by weight of the catalyst; preferably, the support surface area is at least about 100m²Per g, more preferably about 150m²Per gram, even more preferably at least about 200m²/g, most preferably at least about 250m²(ii)/g; the molar ratio of tin to platinum group metal is preferably from about 1: 2 to about 2: 1, more preferably from about 2: 3 to about 3: 2; still more preferably from about 5: 4 to about 4: 5; most preferably from about 9: 10 to about 10: 9. In many cases, the support comprises calcium silicate in an amount effective to balance bronsted acid sites to produce residual alumina (residual alumina) in the silica; typically, from about 1% to about 10% by weight calcium silicate is sufficient to ensure that the carrier is substantially neutral or basic in character. In a particularly preferred embodiment, platinum is present in the hydrogenation catalyst in an amount of at least about 0.75 wt.%, more preferably 1 wt.%; the molar ratio of tin to platinum is from about 5: 4 to about 4: 5; and the carrier comprises at least about 2.5 wt% to about 10 wt% calcium silicate.

It is an aspect of many embodiments of the present invention that greater than about 1000hr may be used^-1、2500hr^-1And even above 5000hr^-1While simultaneously converting at least 90% of the converted acetic acid to ethanol and less than 2% of the acetic acid to ethanol other than one selected from the group consisting of ethanol, acetaldehyde, and ethaneEthyl acetate and ethylene and mixtures thereof. In many embodiments of the invention, the formation of alkanes is low, typically less than 2%, often less than 1%, and in many cases less than 0.5% of the acetic acid passing through the catalyst is converted to alkanes, which have little value other than as fuel or syngas.

In another aspect of the invention, alkanoic acids are hydrogenated by passing a gaseous stream comprising hydrogen and alkanoic acid in a molar ratio of hydrogen to alkanoic acid of at least about 2: 1 in the vapor phase at a temperature of about 125 ℃ to 350 ℃ over a hydrogenation catalyst comprising: a platinum group metal selected from platinum, palladium and mixtures thereof on a siliceous support selected from silica, calcium metasilicate and calcium metasilicate promoted silica; and a promoter selected from the group consisting of tin, rhenium, and mixtures thereof, wherein the silicon-containing carrier is optionally promoted with a promoter selected from the group consisting of: a promoter selected from the group consisting of alkali metals, alkaline earth elements and zinc in an amount of 1-5% by weight of the catalyst; selected from WO in an amount of 1-50% by weight of the catalyst₃、MoO₃、Fe₂O₃And Cr₂O₃Redox (redox) promoters of (i); and TiO in an amount of 1-50% by weight of the catalyst₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃Wherein the acidity of the support is controlled to convert less than 4, preferably less than 2, most preferably less than about 1% of the alkanoic acid to alkane. In many cases, at least one of platinum and palladium is present in an amount of 0.25% to 5% by weight of the catalyst; the total amount of platinum and palladium present is at least 0.5% by weight of the catalyst; the total amount of rhenium and tin present is at least 0.5 to 10 wt%. In the process, the amounts and oxidation states of the platinum group metal, rhenium and tin promoters, and the molar ratio of the platinum group metal to the total moles of rhenium and tin present, are controlled for a catalyst comprising platinum and tin on a basic silica support; and the acidity of the siliceous support is such that at least 80% of the converted acetic acid is converted to a compound selected from the group consisting of alkanol and alkyl acetate, and at the same time less than 4% of the alkanoic acid is converted to an alkanoic acid other than the corresponding alkanol, alkyl acetateEsters and mixtures thereof. Preferably, at least one of platinum and palladium is present in an amount of 0.5% to 5% by weight of the catalyst; the total amount of platinum and palladium present is at least 0.75% to 5% by weight of the catalyst. Preferably, the alkanoic acid is acetic acid, the total amount of tin and rhenium present is at least 1.0% by weight of the catalyst, and the amounts and oxidation states of the platinum group metal, rhenium and tin promoter, and the ratio of platinum group metal to rhenium and tin promoter, are controlled simultaneously; and the acidity of the siliceous support is such that at least 80% of the converted acetic acid is converted to ethanol or ethyl acetate and less than 4% of the acetic acid is converted to compounds other than compounds selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene and mixtures thereof. Preferably, the total weight of rhenium and tin present is from about 1 to 10 percent by weight of the catalyst, and the molar ratio of platinum group metal to the total moles of rhenium and tin is from about 1: 2 to about 2: 1.

In another aspect, the invention relates to a process for hydrogenating acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid at a molar ratio of hydrogen to acetic acid of at least about 4: 1 in the vapor phase at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of a metal component dispersed on an oxide-based support, the hydrogenation catalyst having a composition of:

Pt_vPd_wRe_xSn_yCa_pSi_qO_r，

wherein: the ratio of v to y is 3: 2-2: 3; and/or the w: x ratio is from 1: 3 to 1: 5, p and q are chosen such that p: q is from 1: 20 to 1: 200, wherein r is chosen to satisfy the valence requirement, and v and w are chosen such that:

in this respect, the process conditions and the values of v, w, x, y, p, q and r are preferably selected such that at least 90% of the converted acetic acid is converted to a compound selected from ethanol and ethyl acetate, and at the same time less than 4% of the acetic acid is converted to alkanes. In many embodiments of the invention, p is selected to ensure that the support surface is substantially free of active bronsted acid sites, taking into account any minor impurities present.

Yet another aspect of the invention relates to a process for producing ethanol by reducing acetic acid, the process comprising passing a gaseous stream comprising hydrogen and acetic acid at a molar ratio of hydrogen to acetic acid of at least about 4: 1 in the gas phase at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of a metal component dispersed on an oxide-based support, the hydrogenation catalyst having a composition of:

Pt_vPd_wRe_xSn_yAl_zCa_pSi_qO_r，

wherein: v and y are 3: 2 to 2: 3; w and x are 1: 3 to 1: 5, wherein p and z and the relative positions of the aluminum atoms and the calcium atoms present are controlled such that Bronsted acid sites present on the surface thereof are balanced by calcium silicate; p and q are selected such that p: q is from 1: 20 to 1: 200, wherein r is selected to satisfy valence requirements, and v and w are selected such that:

preferably, in this aspect, the hydrogenation catalystThe agent has a particle size of at least about 100m²Surface area per g, and z and p.gtoreq.z. In many embodiments of the invention, p is selected to also ensure that the support surface is substantially free of active bronsted acid sites that appear to promote the conversion of ethanol to ethyl acetate, given the presence of any minor impurities.

Another aspect of the invention relates to a process for producing ethanol and ethyl acetate by reducing acetic acid, the process comprising passing a gaseous stream comprising hydrogen and acetic acid in a molar ratio of hydrogen to acetic acid of at least about 4: 1 in the vapor phase at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst comprising: a platinum group metal selected from platinum and mixtures of platinum and palladium on a siliceous support selected from silica and silica promoted with up to about 7.5 calcium metasilicate, the platinum group metal being present in an amount of at least about 2.0% and the platinum being present in an amount of at least about 1.5%; and a metal promoter selected from rhenium and tin in an amount of from about 1% to 2% by weight of the catalyst, the molar ratio of platinum to metal promoter being from about 3: 1 to 1: 2; a silicon-containing carrier optionally promoted with a second promoter selected from the group consisting of: a donor (donor) promoter selected from alkali metals, alkaline earth elements and zinc in an amount of 1-5% by weight of the catalyst; selected from WO in an amount of 1-50% by weight of the catalyst₃、MoO₃、Fe₂O₃And Cr₂O₃A redox type accelerator of (a); and TiO in an amount of 1-50% by weight of the catalyst₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃An acidic modifier of (1); and combinations thereof.

In a preferred aspect of the invention, the molar ratio of metal promoter to platinum group metal is from about 2: 3 to about 3: 2, more preferably from about 5: 4 to about 4: 5, and most preferably from about 9: 10 to about 10: 9, while the silicon-containing support has a surface area of at least about 200m²(iv) sodium silicate in an amount sufficient to render the surface of the support substantially alkaline. In some cases, the use of calcium silicate can be controlled such that the number of moles of bronsted acid sites present on its surface is no greater than that present on Saint-Gobain NorProSS61138 silicaThe moles of bronsted acid sites on the surface. In other cases, the silica used may be a high purity fumed silica having a low content of alumina or other impurities. In many cases, such silicas may comprise greater than 99% silica, more preferably greater than 99.5% silica, and most preferably greater than 99.7% silica. In many embodiments of the present invention, the moles of bronsted acid sites present on the surface of the support are available no greater than the moles of bronsted acid sites present on the surface of Saint-Gobain NorPro SS61138 silica, preferably less than half, more preferably less than 25%, still more preferably less than 10% of the moles of bronsted acid sites present on the surface of Saint-Gobain NorPro SS61138 silica, either by controlling the silica purity or by balancing the bronsted acid sites present on the surface with calcium silicate or one of the other suitable stabilizer modifiers discussed herein. The number of acid sites present on the surface of the support can be determined using pyridine titration according to the procedures described in the following documents:

(1) delannay, eds. "Characterisation of heterogenous catalysts"; chapter III: measurement of Acidity of Surfaces, page 370-404; marcel Dekker, inc., n.y.1984.

(2) Brundle, c.a.evans, jr., s.wilson, l.e.fitzpatrick, editors, "Encyclopedia of Materials charateriation"; chapter 12.4: physical and Chemical Adsorption Measurements of Solid surface areas, page 736-744; Butterworth-Heinemann, MA 1992.

(3) G.a.olah, g.k.sura Prakask, editors, "superframes"; john Wiley & Sons, N.Y. 1985.

Throughout the present specification and claims, unless the context indicates otherwise, when measuring surface acidity or the number of acid sites thereon, f. Chapter III: measurement of Acidity of surfaces, page 370-404; techniques described in Marcel Dekker, inc., n.y.1984.

In more preferred aspects, the siliceous support has a surface area of at least about 250m²(iv)/g, the number of moles of available bronsted acid sites present on the surface thereof is not more than half of the number of moles of bronsted acid sites present on the surface of Saint-Gobain NorPro HSA SS61138 silica and the hydrogenation may be carried out at a temperature of about 250 ℃ to 300 ℃.

Reviewing the discussion herein, as will be appreciated by those skilled in the art, in some embodiments, catalyst supports other than the siliceous supports described above may be used, provided that the components thereof are selected to provide the catalyst system with suitable activity, selectivity, and robustness (robust) under the process conditions employed. Suitable supports may include stable metal oxide-based or ceramic-based supports and molecular sieves including zeolites. Thus, also in some embodiments, a carbon support may be used as described in the aforementioned U.S. patent No.5,149,680 to Kitson et al, at column 2, line 64-column 4, line 22, the disclosure of which is incorporated herein by reference.

In many embodiments of the invention, in the case where a mixture of ethanol and ethyl acetate is to be produced simultaneously, the hydrogenation catalyst may comprise: palladium on a siliceous support selected from the group consisting of silica and silica promoted with up to about 7.5 calcium metasilicate, the palladium being present in an amount of at least about 1.5%; and with the metal promoter being rhenium in an amount of from about 1% to about 10% by weight of the catalyst, the molar ratio of rhenium to palladium being from about 4: 1 to about 1: 4, preferably from about 2: 1 to about 1: 3.

In many embodiments of the invention, in situations where it is desired to produce primarily ethanol, the catalyst may consist essentially of: platinum on a siliceous support consisting essentially of silica promoted with from about 3 up to about 7.5% calcium silicate, wherein the platinum is present in an amount of at least about 1.0%, and a tin promoter in an amount of from about 1% to 5% by weight of the catalyst, in many embodiments of the invention the molar ratio of platinum to tin is from about 9: 10 to 10: 9. In thatIn some cases, a minor amount of another platinum group metal may be included, most commonly palladium which is the catalytic metal in the formulation. In many embodiments of the invention, the platinum group metal is present in an amount of at least about 2.0%, the platinum is present in an amount of at least about 1.5%, preferably 2.5 to 3.5% by weight, platinum, the tin promoter is present in an amount of about 2% to 5% by weight of the catalyst, and the process is carried out at a temperature of about 250 ℃ to 300 ℃ for at least about 1000hr^-1Is carried out at a pressure of at least 2 atm. The ratio of tin to platinum is preferably from 2: 3 to 3: 2, more preferably from 4: 5 to 5: 4, most preferably from 9: 10 to 10: 9. In still other embodiments where it is desired to produce primarily ethanol, the catalyst may comprise platinum on a siliceous support consisting essentially of silica promoted with from about 3 up to about 7.5% calcium silicate, wherein the platinum is present in an amount of at least about 1.0% and the tin promoter is present in an amount of from about 1% to 5% by weight of the catalyst, in many embodiments of the invention the molar ratio of platinum to tin is from about 9: 10 to 10: 9.

Another aspect of the invention relates to a particulate catalyst for hydrogenating alkanoic acids to the corresponding alkanols, the particulate catalyst comprising: a platinum group metal selected from platinum, palladium and mixtures thereof on a siliceous support selected from silica and silica promoted with about 3.0 up to about 7.5 calcium metasilicate, the siliceous support having a surface area of at least about 150m²(ii)/g; the tin promoter is present in an amount of about 1% to about 3% by weight of the catalyst, and the molar ratio of platinum to tin is about 4: 3 to about 3: 4; the composition and structure of the silicon-containing carrier is selected such that its surface is substantially basic.

Another aspect of the invention relates to a particulate hydrogenation catalyst consisting essentially of: a silicon-containing carrier having dispersed thereon a platinum group metal selected from platinum, palladium and mixtures thereof and a promoter selected from tin, cobalt and rhenium, the silicon-containing carrier having at least about 175m²(ii) a surface area per gram and is selected from the group consisting of silica, calcium metasilicate, and calcium metasilicate promoted silica (having calcium metasilicate located on its surface), the surface of the siliceous support being substantially free of bronsted acid sites due to alumina not being equilibrated with calcium. Is most suitable for simultaneous productionIn those variations of ethanol and ethyl acetate, the total weight of platinum group metals present is 0.5% to 2%, the amount of palladium present is at least 0.5%, the promoter is rhenium, the weight ratio of rhenium to palladium is 10: 1 to 2: 1, and the amount of calcium metasilicate is 3 to 90%.

In those aspects most suitable for producing ethanol at high selectivity, the total weight of platinum group metals present is from 0.5 to 2%, the amount of platinum present is at least 0.5%, the promoter is cobalt, the weight ratio of cobalt to platinum is from 20: 1 to 3: 1, the amount of calcium silicate is from 3 to 90%, and for producing ethanol with a catalyst having extended life, the hydrogenation catalyst comprises from 2.5 to 3.5 wt% platinum, from 3 wt% to 5 wt% dispersed over a surface area of at least 200m²(ii) per gram of tin on the high surface area pyrogenically obtained silica promoted with an effective amount of calcium metasilicate to ensure that the surface thereof is substantially free of bronsted acid sites not equilibrated by the calcium metasilicate, the molar ratio of platinum to tin being from 4: 5 to 5: 4.

In another catalyst of the invention, the platinum group metals are present in a total amount of 0.5 to 2%, the palladium is present in an amount of at least 0.5%, the promoter is cobalt, the weight ratio of cobalt to palladium is 20: 1 to 3: 1, and the calcium silicate is present in an amount of 3 to 90%.

Yet another catalyst of the invention is a hydrogenation catalyst comprising 0.5 to 2.5 weight percent palladium, 2 weight percent to 7 weight percent rhenium, the weight ratio of rhenium to palladium being at least 1.5: 1.0, wherein both rhenium and palladium are dispersed on a siliceous support comprising at least 80% calcium metasilicate.

It has been found that for the hydrogenation of acetic acid to ethanol, an unexpectedly high activity and lifetime combined with excellent selectivity is obtained from a catalyst selected from the group consisting of:

(i) a catalyst having both a platinum group metal selected from platinum, palladium and mixtures thereof and tin or rhenium on a siliceous support selected from silica, calcium metasilicate and calcium metasilicate promoted silica;

(ii) a catalyst having both palladium and rhenium supported on a siliceous support comprising silica selected from the group consisting of silica, calcium metasilicate, and calcium metasilicate promoted silica, wherein the siliceous support is optionally promoted with 1% to 5% of a promoter selected from the group consisting of alkali metals, alkaline earth elements, and zinc; the promoters are preferably added to the catalyst formulation in the form of the respective nitrates or acetates of these promoters (particularly preferably potassium, cesium, calcium, magnesium and zinc);

(iii) platinum promoted with cobalt on a high surface area siliceous support selected from the group consisting of silica, calcium metasilicate, and calcium metasilicate promoted silica; and

(iv) palladium promoted with cobalt on a high surface area siliceous support selected from the group consisting of silica, calcium metasilicate, and calcium metasilicate promoted silica.

Another aspect of the invention relates to a process for hydrogenating alkanoic acids which comprises passing a gaseous stream comprising hydrogen and alkanoic acid in a molar ratio of hydrogen to alkanoic acid of at least about 2: 1 in the vapor phase at a temperature of about 125 ℃ to 350 ℃ over a hydrogenation catalyst comprising:

a. a platinum group metal selected from platinum, palladium and mixtures thereof on a siliceous support selected from silica, calcium metasilicate and calcium metasilicate promoted silica; and

b. a promoter selected from the group consisting of tin and rhenium,

c. wherein the silicon-containing carrier is optionally promoted with a promoter selected from the group consisting of:

i. a promoter selected from the group consisting of alkali metals, alkaline earth elements and zinc in an amount of 1-5% by weight of the catalyst;

from 1 to 50% by weight of the catalyst of an amount selected from WO₃、MoO₃、Fe₂O₃And Cr₂O₃A redox type accelerator of (a); and

an amount of 1-50% by weight of the catalyst selected from TiO₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃The acidic modifier of (1).

Preferably, the alkanoic acid is acetic acid, and the platinum (if present) is present in an amount of 0.5% to 5% by weight of the catalyst; palladium (if present) is present in an amount of 0.25% to 5% by weight of the catalyst; the total amount of platinum and palladium present is at least 0.5% by weight of the catalyst; tin is present in an amount of at least 0.5-5% and the ratio of platinum to tin is as previously described.

In another aspect of the invention, the surface area of the silicon-containing support is at least about 150m²Per gram, more preferably at least about 200m²/g, most preferably at least about 250m²(ii) in terms of/g. In a more preferred embodiment, the siliceous support comprises up to about 7.5% calcium metasilicate. In further embodiments, the siliceous support comprises up to about 90% calcium metasilicate. In all embodiments, especially when substantially pure ethanol is to be produced, it may be quite advantageous to control the acidity of the support. In the case where silica alone is used as support, it is quite advantageous to ensure that the amount of alumina (which is a common contaminant of silica) is low, preferably below 1%; more preferably less than 0.5%; most preferably below 0.3 wt%. In this connection, the so-called pyrogenic silica is greatly preferred, since it is generally obtained in purities of more than 99.7%. In this application, when referring to high purity silica, it refers to silica in which acidic contaminants such as alumina are present at levels of less than 0.3 wt.%. In the case where calcium metasilicate promoted silica is used, it is generally not necessary to be very critical as to the purity of the silica used as the support, although alumina is undesirable and will generally not be added intentionally.

In a more preferred embodiment of the invention, platinum (if present) is present in an amount of 1% to 5% by weight of the catalyst; palladium (if present) is present in an amount of 0.5% to 5% by weight of the catalyst; and the total amount of platinum and palladium present is at least 1% by weight of the catalyst.

In another preferred embodiment of the invention wherein the support is substantially pure high surface area silica, preferably pyrogenically formed silica, the tin is present in an amount of from 1% to 3% by weight of the catalystMore preferably, the molar ratio of tin to platinum group metal is from about 1: 2 to about 2: 1; still more preferably, the molar ratio of tin to platinum is from about 2: 3 to about 3: 2; also most preferably, the molar ratio of tin to platinum is from about 5: 4 to about 4: 5. In which the carrier also contains a minor amount of CaSiO₃Or from about 2% to about 10% of other stabilizer modifiers, larger amounts of acidic impurities can be tolerated as long as they are balanced by the appropriate amount of the substantially basic stabilizer modifier (counter-balance).

In another aspect of the invention, it is preferred to carry out the process at a temperature of from about 225 ℃ to 300 ℃, more preferably from 250 ℃ to 300 ℃, wherein the hydrogenation catalyst comprises: a platinum group metal selected from platinum and mixtures of platinum and palladium on a siliceous support selected from silica and silica promoted with up to about 7.5 calcium metasilicate, the platinum group metal being present in an amount of at least about 2.0% and the platinum being present in an amount of at least about 1.5%; the amount of tin promoter is from about 1% to about 2% by weight of the catalyst, and the molar ratio of platinum to tin is from about 3: 1 to about 1: 2, wherein the silicon-containing support is optionally promoted with a promoter selected from the group consisting of: a promoter selected from the group consisting of alkali metals, alkaline earth elements and zinc in an amount of 1-5% by weight of the catalyst; selected from WO in an amount of 1-50% by weight of the catalyst₃、MoO₃、Fe₂O₃And Cr₂O₃A redox type accelerator of (a); and an amount of 1-50% by weight of the catalyst selected from TiO₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃The acidic modifier of (1).

In a particularly preferred process of the invention for hydrogenating alkanoic acids, the catalyst comprises: a platinum group metal selected from platinum, palladium and mixtures thereof on a siliceous support selected from the group consisting of high surface area, high purity silica and high surface area silica promoted with up to about 7.5 calcium metasilicate, the platinum group metal being present in an amount of at least about 2.0% and the platinum being present in an amount of at least about 1.5%; the amount of tin promoter is about 1% to 5% by weight of the catalyst and the molar ratio of platinum to tin is about 3: 2 to 2: 3. Preferably, the high purity silica is pyrogenically produced and then tablettedOr pelletized into a dense form sufficient for use in a fixed bed catalyst. However, even in the case of high purity silica, 2500hr for a temperature of about 275 ℃ in the presence of acetic acid vapor^-1Or higher space velocities for extended periods of time, of weeks or even months, the presence of the stabilizer modifier, especially calcium silicate, appears to extend or stabilize the activity and selectivity of the catalyst. In particular, a stability may be reached where the catalyst activity may decrease by less than 10% over a period of 1 week (168 hours) or 2 weeks (336 hours) or even more than 500 hours. It can therefore be appreciated that the catalyst of the present invention is fully useful for commercial scale industrial applications for the hydrogenation of acetic acid, particularly for the production of high purity ethanol and mixtures of ethyl acetate and ethanol.

Another aspect of the invention relates to a hydrogenation catalyst based on group VIII metals (Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt and Os) or other transition metals (in particular Ti, Zn, Cr, Mo and W) on an oxide based support incorporating oxides and metasilicates of alkaline earth metals, alkali metals, zinc, scandium, yttrium, and precursors of these oxides and metasilicates, and mixtures thereof, in a sufficient amount to: counteracting acid sites present on the surface thereof; imparting resistance to shape change at temperatures encountered with acetic acid hydrogenation (shape change due primarily to sintering, grain growth, grain boundary migration, defect and dislocation migration, plastic deformation, and/or other temperature-induced microstructural changes, among other things); or both.

In another embodiment of the process of the invention, the catalyst is selected from:

(i) a catalyst having both a platinum group metal selected from platinum, palladium and mixtures thereof and tin or rhenium on a siliceous support selected from silica, calcium metasilicate and silica stabilized with and modified by calcium metasilicate;

(ii) a catalyst having both palladium and rhenium supported on a siliceous support comprising silica selected from the group consisting of calcium metasilicate and calcium metasilicate promoted silica, wherein the siliceous support is optionally promoted with 1% to 5% of a promoter selected from the group consisting of alkali metals, alkaline earth elements, and zinc;

(iii) platinum promoted with cobalt on a siliceous support selected from the group consisting of silica, calcium metasilicate, and calcium metasilicate promoted silica; and

(iv) palladium promoted with cobalt on a siliceous support selected from the group consisting of silica, calcium metasilicate, and calcium metasilicate promoted silica.

Generally, the siliceous support incorporates a promoter selected from the group consisting of: a stabilizer-modifier comprising oxides and metasilicates of alkali metals, alkaline earth elements, and zinc, and precursors thereof, in an amount of 1-5% by weight of the catalyst; selected from WO in an amount of 1-50% by weight of the catalyst₃、MoO₃、Fe₂O₃And Cr₂O₃A redox type accelerator of (a); and an amount of from 1 to 50% by weight of the catalyst selected from TiO₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃The presence of the acidic modifier is beneficial to producing ethyl acetate and ethanol.

Another aspect of the invention relates to a particulate catalyst for hydrogenating alkanoic acids to the corresponding alkanols, the particulate catalyst comprising: a platinum group metal selected from platinum, palladium and mixtures thereof on a siliceous support selected from silica, silica promoted with up to about 7.5 calcium metasilicate, and mixtures thereof, the siliceous support having a surface area of at least about 150m²(ii)/g; the amount of tin promoter is from about 1% to about 2% by weight of the catalyst, the molar ratio of platinum to tin is from about 3: 2 to about 3: 2, and the siliceous support is optionally promoted with a promoter selected from the group consisting of: a promoter selected from the group consisting of alkali metals, alkaline earth elements and zinc in an amount of 1-5% by weight of the catalyst; selected from WO in an amount of 1-50% by weight of the catalyst₃、MoO₃、Fe₂O₃And Cr₂O₃A redox type accelerator of (a); and an amount of from 1 to 50% by weight of the catalyst selected from TiO₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃The acidic modifier of (1).

An alternative embodiment of the present invention is directed to a particulate hydrogenation catalyst consisting essentially of: a silicon-containing carrier having dispersed thereon a platinum group metal selected from platinum, palladium and mixtures thereof and a promoter selected from tin, cobalt and rhenium, the silicon-containing carrier having at least about 175m²(ii) surface area per gram and is selected from silica, calcium metasilicate, and calcium metasilicate-promoted silica; the siliceous support is optionally promoted with: 1-5% by weight of the catalyst of a promoter selected from the group consisting of alkali metals, alkaline earth elements and zinc; selected from WO in an amount of 1-50% by weight of the catalyst₃、MoO₃、Fe₂O₃And Cr₂O₃A redox type accelerator of (a); and an amount of from 1 to 50% by weight of the catalyst selected from TiO₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃The acidic modifier of (1). In a more preferred embodiment of the invention, the total weight of platinum group metals present is from 2 to 4%, the amount of platinum present is at least 2%, the promoter is tin, the molar ratio of platinum to tin is from 2: 3 to 3: 2, and the amount of calcium metasilicate is from 3 to 7%. In another more preferred embodiment of the invention, the total weight of platinum group metals present is from 0.5% to 2%, the amount of palladium present is at least 0.5%, the promoter is rhenium, the weight ratio of rhenium to palladium is from 10: 1 to 2: 1, and the amount of calcium metasilicate is from 3 to 90%. In a third more preferred embodiment of the invention, the total weight of platinum group metals present is from 0.5 to 2%, the amount of platinum present is at least 0.5%, the promoter is cobalt, the weight ratio of cobalt to platinum is from 20: 1 to 3: 1, and the amount of calcium silicate is from 3 to 90%. In a fourth more preferred embodiment of the invention, the total weight of platinum group metals present is from 0.5 to 2%, the amount of palladium present is at least 0.5%, the promoter is cobalt, the weight ratio of cobalt to palladium is from 20: 1 to 3: 1, and the amount of calcium silicate is from 3 to 90%.

Brief description of the drawings

The present invention is described in detail below with reference to the attached drawing figures, wherein like numerals indicate like parts. In these drawings:

figures 1 and 2 depict the selectivity and yield performance of the catalyst of the present invention.

Figures 3A-3C depict the relative temperature insensitivity of selectivity and yield of the catalysts of the present invention as a function of the performance obtained when hydrogenating acetic acid at 225 ℃ over a catalyst activated at 225 ℃.

FIGS. 4A-4C depict selectivity, conversion and yield as a function of the platinum to tin ratio of the preferred platinum tin catalyst of the present invention.

Figures 5A and 5B depict the selectivity of the most preferred catalysts of the invention supported on high surface area silica for ethanol production and the high yields obtained therewith.

Figures 6A and 6B and figures 7A and 7B depict the excellent selectivity obtained at low temperatures using the most preferred catalysts of the invention based on calcium metasilicate promoted high surface area silica. It is recognized that selectivity to ethanol is high.

Figures 8, 9 and 10 depict the effect of rhenium mass fraction on acetic acid hydrogenation when using the palladium-on-silica rhenium catalyst of the present invention.

Fig. 11 and 12 depict the performance of platinum and cobalt catalysts supported on silica.

Detailed Description

Even with ever fluctuating market conditions, the selectivity, activity and catalyst life reported in the literature for the catalytic hydrogenation of acetic acid to ethanol for large scale operations suggests that these, which need to compete with other ethanol production processes, are often economically disadvantageous. One yield estimate required for commercial viability is that for a yield of about 200g ethanol/kg catalyst/hour, an ethanol selectivity of over about 50% would be required. The catalysts of the present invention far exceed these requirements.

In the description that follows, all numbers disclosed herein are approximate values, regardless of whether they are used in conjunction with the word "about" or "approximately". These values may vary by 1%, 2%, 5%, or sometimes 10-20%. Provided that it has the lower limit R^LAnd an upper limit R^UTo any numerical range that falls within such range, and to any numerical range or subrange that falls within such range, is also specifically disclosed. In particular, the following values within this range are specifically disclosed: r ═ R^L+k^★(R^U-R^L) Wherein k ranges from 1% to 100% and increments are 1%, i.e. k is 1%, 2%, 3%, 4%, 5%,.., 50%, 51%, 52%,.., 95%, 96%, 97%, 98%, 99% or 100%. Also, any numerical range defined by two R numbers defined above is specifically disclosed.

Figures 1 and 2 depict the selectivity and productivity performance of the catalysts of the present invention and show in graphical form the greatly improved selectivity and productivity achievable with these catalysts at various operating temperatures. In particular, the ethanol selectivity was about 60% at 280 ℃ and 296 ℃. In this evaluation, it is important to remember that ethyl acetate is also a commodity of considerable economic importance and value, and even if the primary objective is to produce ethanol, any acetic acid converted to ethyl acetate remains of considerable value, while any alkanes produced as by-products are generally much less valuable than the feedstock. In FIG. 1, the yields in grams of ethanol produced per kilogram of catalyst per hour of operation are indicated by squares, and at the same time the yields of ethyl acetate are indicated by circles and the yields of acetaldehyde are indicated by diamonds, as a function of time (in hours). Clearly, during this run, the operating temperature was increased during the run as shown to demonstrate the effect of operating temperature on yield and selectivity. In fig. 2, the selectivity for ethanol as defined below is represented by circles and at the same time the selectivity for ethyl acetate as defined below is represented by squares and the selectivity for acetaldehyde is represented by diamonds as a function of the run time.

Fig. 3A-3C depict the relative temperature insensitivity of the selectivity of the catalysts of the present invention to the reduction temperature of the metal precursor. This characteristic is significant for commercial viability, as the reaction can be carried out in vessels that are not specially constructed to maintain a generally uniform temperature throughout, often these vessels are referred to as "adiabatic reactors" because little precautions are taken to accommodate temperature changes that accompany the reaction process, although the catalyst is typically "diluted" with quartz chips or other inert particles to regulate the reaction. Figure 3A reports the results of an experiment in which the catalyst was reduced with hydrogen at the temperature shown at c and then acetic acid was hydrogenated over the catalyst at 250 c. The upper line represents the selectivity of the particular catalyst to ethanol, while the lower line represents the selectivity to ethyl acetate. In fig. 3B, the yield results of the experiment are given, with the ethanol yield recorded on-line and the ethyl acetate yield recorded off-line. In fig. 3C, the results of the conversion (as defined below) of this experiment are shown as a function of reduction temperature. In addition, acetic acid is also hydrogenated at a temperature of 225 ℃ over a catalyst reduced or activated at 225 ℃. The points on fig. 3B and 3C also include the present results of this experiment in which acetic acid was hydrogenated over a catalyst reduced at 225 ℃. It can be appreciated that hydrogenation over such a catalyst at a temperature of 225 ℃ results in reduced ethanol selectivity and reduced conversion.

FIGS. 4A-4C depict the selectivity, conversion and yield in the catalytic hydrogenation of acetic acid under conditions that vary with the platinum to tin ratio in the preferred platinum-tin catalysts of the present invention with respect to Pt on SiO₂-Pt_xSn_(1-x)(∑[Pt]+[Sn]1.20 mmol): using 2.5ml of solid catalyst (14/30 mesh, 1: 1 dilution (v/v with quartz chips, 14/30 mesh), at an operating pressure of p-200 psig (14bar), the feed rates of acetic acid, hydrogen and nitrogen diluents were 0.09g/min HOAc; 160sccm/min H, respectively₂(ii) a And 60sccm/minN₂(ii) a The total space velocity (GHSV) in the reaction time of 12 hours was 6570h^-1. It can be appreciated that in this experiment, the high surface area was substantially pure for the loadThose catalysts on silica, in a molar ratio of about 1 to 1, maximize selectivity to ethanol production. (throughout this specification, the lower case letter "l" is used for ascending to avoid ambiguity arising from similarity or even identity of symbols used in many fonts for the numeral 1 and the roman alphabet lower case 12 letter). In each of FIGS. 4A-4C, X is on the horizontal axis (horizontal access axis)_i(Pt) represents the mass fraction of platinum in the catalyst, which is 0-1, and at the same time the selectivity, conversion and yield are as indicated above, representing the selectivity of the catalyst to ethanol and ethyl acetate as shown in fig. 4A, with the selectivity to ethanol peaking at a mass fraction of 50% as shown in fig. 4B, and the acetic acid conversion also peaking as the ethanol yield peaked as shown in fig. 4C.

Fig. 5A and B depict the selectivity and yield for ethanol production and the high yields obtained therewith for the most preferred catalysts of the invention supported on high surface area silica. In fig. 5A, the yield in grams per kilogram of catalyst per hour of operation is shown on the vertical axis, where ethanol yield is represented by squares, ethyl acetate yield is represented by circles, and acetaldehyde yield is represented by diamonds. Similarly, in fig. 5B, the selectivity as defined below as a function of the run time (in hours) on the horizontal axis is shown on the vertical axis, again with ethyl acetate selectivity represented by circles, ethanol selectivity represented by squares, and acetaldehyde selectivity represented by diamonds.

Fig. 6A and B and fig. 7A and B use the same format as fig. 5A and B to describe the selectivity obtained at low temperatures using a preferred catalyst of the invention based on calcium metasilicate promoted high surface area silica. It can be appreciated that the ethanol selectivity was greater than 90% throughout the run.

Fig. 8-12 are discussed with respect to related embodiments.

The invention is described in detail below with reference to a number of embodiments for the purpose of illustration and description only. Modifications to the specific embodiments within the spirit and scope of the invention and set forth in the appended claims will be readily apparent to those skilled in the art.

Unless more specifically limited as hereinafter defined, the terms used herein take their ordinary meanings, and unless otherwise indicated, "%" and like terms refer to weight percent. Generally, when discussing the composition of the support, percentages in the composition include oxygen and the ion or metal attached thereto, while when discussing the weight of the catalytic metal, the weight of oxygen attached thereto is ignored. Thus, in a support comprising 95% silica and 5% alumina, this composition is based on alumina having a formula weight of 101.94 and silica having a formula weight of 60.09. However, when referring to a catalyst having 2% platinum and 3% tin, the weight of any oxygen that may be attached thereto is ignored.

"conversion" is expressed as a mole percent based on acetic acid in the feed.

"selectivity" is expressed as mole percent based on converted acetic acid. For example, if the conversion is 50 mole% and 50 mole% of the converted acetic acid is converted to ethanol, it means that the ethanol selectivity is 50%. Ethanol selectivity was calculated from Gas Chromatography (GC) data as follows:

without intending to be bound by theory, it is believed that the conversion of acetic acid to ethanol according to the present invention involves one or more of the following reactions:

the ethanol is obtained by hydrogenating acetic acid.

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Acetic acid hydrogenation to obtain ethyl acetate

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Cracking ethyl acetate to obtain ethylene and acetic acid

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Dehydration of ethanol to ethylene

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The selective catalyst for the catalytic hydrogenation of acetic acid to ethanol is selected from those described below:

(i) catalyst having a platinum group metal selected from platinum, palladium and mixtures thereof in combination with tin or rhenium on a siliceous support selected from silica, calcium metasilicate and silica promoted with calcium metasilicate

(ii) Catalysts having in combination the above-described palladium and rhenium supported on a silicon-containing support optionally promoted with from 1% to 5% of a first promoter selected from the group consisting of alkali metals, alkaline earth elements and zinc, the promoters preferably being added to the catalyst formulation in the form of the respective nitrates or acetates of these promoters, particularly preferably potassium, cesium, calcium, magnesium and zinc;

(iii) platinum promoted with cobalt on a silicon-containing support; and

(iv) palladium promoted with cobalt on a siliceous support.

As will be readily appreciated by those skilled in the art, the process of the present invention may be carried out in various configurations using fixed bed reactors or fluidized bed reactors. In many embodiments of the invention, an "adiabatic" reactor may be used; that is, there is little or no need for internal piping (plumbig) through the reaction zone to add or remove heat. Alternatively, a shell-and-tube reactor provided with a heat transfer medium can be used. In many cases, the reaction zone may be housed in a single vessel or in a series of vessels with heat exchangers in between. It is expressly contemplated that the acetic acid reduction process using the catalyst of the present invention may be conducted in an adiabatic reactor, since such reactor configurations are generally much less capital intensive than shell and tube configurations.

Various catalyst supports known in the art may be used to support the acetic acid hydrogenation catalyst. Examples of such supports include, without limitation, iron oxides, silica, alumina, titania, zirconia, magnesia, calcium silicate, carbon, graphite, and mixtures thereof. For the present invention, preference is given to using siliceous supports selected from the group consisting of silica, calcium metasilicate and calcium silicate promoted silica, with SiO being particularly desirable when the granulation is in a form sufficiently dense for use in a fixed bed reactor₂Fumed silica in an amount of at least 99.7%. It has been found that high purity, high surface area silica, optionally promoted with calcium metasilicate, particularly HSA SS61138 grade from Saint-gobain norpro, is unexpectedly superior to other supports used in the catalysts of the present invention. The silica used as support according to the invention preferably has a particle size of at least 100m²A/g, more preferably at least 150m²Per g, more preferably at least 200m²In g, most preferably about 250m²Surface area in g. Throughout this specification, the term "high surface area silica" is understood to mean silica having a surface area of at least 250m²Silica per gram surface area. The activity/stability of the siliceous support can be modified by the incorporation of minor amounts of other components as described below. Any convenient particulate form may be used including pellets, extrudates, spheres, spray dried, rings, penta-spoked wheels (pentaring), trilobes and tetralobes, although it is generally preferred for the present application to use cylindrical pellets.

Influence of the catalyst support.

Except for metal precursors (i.e. halogens, Cl)^-NO compared to (vs.) halogen-free₃ ^-) And the preparation conditions, the metal-support interaction produced strongly depends on the structure and properties of the underlying support.

The effect of alkaline and acidic modifiers was investigated for various silica-supported Pt-Sn materials. For all materials, unless otherwise noted, the molar ratio between Pt and Sn was kept at 1: 1, also keeping the total metal loading constant. In particular on acidic supports such as SiO₂、SiO₂-TiO₂KA160 (i.e., SiO)₂-Al₂O₃) And the catalyst prepared on H-ZSM5 produced high acetic acid conversion but lower ethanol selectivity. It is noted that the H-ZSM5 catalyst actually produced diethyl ether as the major product, most likely formed by ethanol dehydration. Based on SiO₂-TiO₂And based on KA160 (i.e., SiO)₂-Al₂O₃) Both produce high conversion and similar selectivity to EtOH and EtOAc, in both cases EtOAc is the major product. The presence of Lewis acidity in the underlying catalyst support appears to be beneficial for higher acetic acid conversion. Although SiO is present₂-TiO₂Acidity in (1) is mainly based on Lewis acidity, but KA160 (silica-alumina) material also has strong bronsted acid sites, which can catalyze the formation of EtOAc from residual acetic acid and EtOH. The H-ZSM5 based catalyst has even stronger acidic zeolite (zeolytic) bronsted acid sites and shape selectivity, since the small pores may also contribute to the acid-catalyzed formation of diethyl ether by ethanol dehydration. The addition of an alkaline modifier to any of the supports studied generally resulted in an increase in selectivity to ethanol with a significant decrease in acetic acid conversion. SiO was found for entry 2 in Table A₂-CaSiO₃(5) -Pt (3) -Sn (1.8), maximum selectivity to ethanol of 92%, using CaSiO₃Promoted even pure TiO₂Ethanol was produced with a selectivity of about 20%. SiO 2₂-TiO₂And TiO₂-CaSiO₃The comparison between suggests that the site density of the acid sites (Lewis) may also be of importance and that further optimization of the acidic properties of the catalyst support may most likely be achieved by carefully varying the basic and acidic promoters in conjunction with the specific preparation method.

TABLE A addition in the gas phase of acetic acidSummary of catalyst activity data for catalyst support modifiers in hydrogen. Reaction conditions are as follows: 2.5ml of solid catalyst (14/30 mesh, 1: 1 dilution (v/v, with quartz chips, 14/30 mesh), p-200 psig (14bar), 0.09g/min HOAc; 160sccm/minH₂；60sccm/min N₂；GHSV＝6570h^-1(ii) a The reaction time was 12 hours.

¹The preparation of the individual catalysts is described in detail herein. The numbers in parentheses indicate the amount of the actual component (metal, metal oxide) in weight%.

²Product selectivity (% by weight) was calculated by GC analysis on a calibrated reliable sample.

³Acetic acid conversion (%) was calculated as follows: [ HOAc)]Conversion,% { [ HOAc ]](feed, mmol/min) - [ HOAc](effluent, mmol/min)/[ HOAc](feed, mmol/min) } 100.

⁴The main product obtained with this catalyst was diethyl ether (EtOEt) with a selectivity of 96% and a yield of 2646 g/kg/h.

Comparison KA160 (SiO)₂-5％Al₂O₃) And KA160-CaSiO₃A clear shift in selectivity to ethanol was observed for the promoted catalyst. See entries 2, 6 and 7 in Table A, although at 84%, the catalyst selectivity was still lower than SiO₂-CaSiO₃The selectivity observed for the base material, but with the acetic acid conversion remaining at 43%, is for SiO₂-CaSiO₃(5) Almost twice the acetic acid conversion seen with-Pt (3) -Sn (1.8). All CaSiO except for the "acidic modifier" property₃The promoted material appears to show improved stability over a longer period of time (albeit at a lower conversion). In particular, greater than 220 hours under various reaction conditionsTime of reaction of SiO₂-CaSiO₃(5) the-Pt (3) -Sn (1.8) catalyst exhibits a reduction in activity of less than 10%. With respect to selectivity, in SiO₂And SiO₂-CaSiO₃The two Re — Pd catalysts prepared above also showed similar trends. Entries 9 and 10 in table a, for both materials, although the conversion remained below 10%, for CaSiO₃The promoted material observed a significant shift in selectivity to ethanol. Additional information on yield is provided in table 4.

Thus, without being bound by theory, the modification and stabilization of the oxide-based support for the acetic acid hydrogenation catalyst by the introduction of the non-volatile stabilizer-modifier has any of the following effects: counteracting acid sites present on its surface; or thermally stabilizing its surface such that the desired improvement in ethanol selectivity, extended catalyst life, can be obtained; or both. In general, modifiers based on oxides in their most stable valence state can have low vapor pressure and, therefore, be quite nonvolatile. Thus, hydrogenation catalysts based on group VIII metals (Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt and Os) or other transition metals (in particular Ti, Zn, Cr, Mo and W) on an oxide-based support preferably incorporate alkaline earth metal, alkali metal, zinc, scandium, yttrium oxides and metasilicates, precursor forms of these oxides and metasilicates, and mixtures thereof, in sufficient amounts on the surface or inside the support itself, so that: counteracting acid sites present on the surface thereof; imparting resistance to shape change at temperatures encountered with acetic acid hydrogenation (shape change due primarily to sintering, grain growth, grain boundary migration, defect and dislocation migration, plastic deformation, and/or other temperature-induced microstructural changes, among other things); or both.

In the present invention, the amount of metal loading on the support is not critical and can vary from about 0.3 wt.% to about 10 wt.%. Metal loadings of about 0.5 wt% to about 6 wt% based on the weight of the catalyst are particularly preferred. Because of their extreme expense, platinum group metals are typically used in fairly carefully controlled amounts, usually smallAt 10 wt% of the total catalytic composition. As low as 0.25-5% platinum, when combined with other catalytic elements as described herein, can provide excellent selectivity, lifetime, and activity. Typically, it is preferred to use 0.5 to 5%, more preferably 1 to 3% platinum in the platinum-containing catalyst of the present invention. In the case of a platinum tin catalyst, it is preferred to use a combination of 0.10-5% tin, more preferably 0.25-3% tin, still more preferably 0.5-2.5% tin, most preferably about 3% platinum and about 1.5% tin (corresponding quite closely to a 1: 1 molar ratio of platinum to tin), or a less proportional amount based on a lower weight percent of platinum when supported on high surface area silica/calcium metasilicate. For this catalyst, it is preferred to use a siliceous support selected from the group consisting of high purity high surface area silica, calcium metasilicate, and high surface area silica promoted with calcium metasilicate as described above. Thus, it can be appreciated that the amount of calcium metasilicate can vary widely from 0 up to 100 weight percent. Since calcium metasilicate tends to have a relatively low surface area, it is preferred for the catalyst to include at least about 10% high surface area silica in the support of the present invention, more preferably as the support of the present invention, it is preferred to use about 95% high surface area silica, i.e., a SS61138 High Surface Area (HSA) silica catalyst support from Saint-Gobain NorPro having a height of 250m²Surface area per gram; a median pore diameter of 12 nm; 1.0cm measured by mercury intrusion porosimetry³Total pore volume per gram and about 22lbs/ft³The bulk density of (2).

The catalyst of the present invention is a particulate catalyst in the sense that it is not impregnated into a washcoat on a monolith support like automotive catalysts and diesel soot trapping devices, the catalyst of the present invention is formed into particles, sometimes also referred to as beads or pellets, having any of a variety of shapes, and the catalytic metal is provided to the reaction zone by placing a plurality of these formed catalysts in a reactor. Common shapes include extrudates having any cross section, which are generalized cylinders in the sense that the generators defining the extrudate surface are parallel lines. Spheres, spray dried microspheres, rings, five-spoke wheels, and multi-lobes are all useful. Typically, the shape is selected empirically based on the recognized ability to effectively contact the gas phase with the catalyst.

A highly suitable platinum tin catalyst comprises a support at a surface area of about 250m²About 3 wt.% platinum, 1.5 wt.% tin on per gram of high surface area silica promoted with about 0.5% to 7.5% calcium metasilicate. Catalyst lifetimes of several hundred hours run time have been achieved with this composition at 280 ℃. In many cases, it will be possible to partially replace the platinum with palladium in the above-mentioned compositions.

Catalysts similar to those described in the preceding paragraph but containing relatively small amounts of extremely expensive platinum promoted with a substantial amount of cobalt provide good initial catalytic activity but tend not to exhibit as long catalyst life as the platinum tin catalysts described above. The preferred grade of the siliceous support (hierarchy) of the catalyst is substantially the same as the platinum tin catalyst. Preferred catalysts of this type comprise 0.25 to 5% platinum, more preferably 0.3 to 3% platinum, and most preferably 0.5 to 1.5% platinum in combination with about 1% to about 20% cobalt, more preferably about 2% to about 15% cobalt, and more preferably about 8 to 12% cobalt. Even though these catalysts are less durable than the platinum tin catalysts described above, in many cases this can be largely offset by the greatly reduced amount of platinum required, the lower cost of cobalt compared to the platinum group metals, and the excellent initial selectivity. It will of course be appreciated that in many cases the lack of activity can be compensated for by appropriate recycle streams or the use of larger reactors, but it is more difficult to compensate for poor selectivity.

Catalysts based on palladium promoted with rhenium or cobalt provide excellent catalytic activity and a slightly lower selectivity, this loss of selectivity being exacerbated at reaction temperatures above 280 ℃ resulting in the formation of increased amounts of acetaldehyde, carbon dioxide and even hydrocarbons. Cobalt-containing catalysts typically exhibit somewhat better selectivity than the corresponding rhenium catalysts; however, while both provide unexpectedly long-lived catalytic activity, neither provide as outstanding catalyst life as the most preferred platinum/tin catalysts on high purity alumina stabilized and modified with calcium metasilicate. The catalyst may furthermore be supported on a siliceous support stabilized and modified with the above-mentioned oxides and metasilicates of group I, group II and zinc, as well as their precursors and mixtures thereof. Highly suitable precursors include zinc, alkali and alkaline earth metal acetates and nitrates, which may optionally be incorporated into the siliceous support in amounts of about 1-5% based on the weight of the metal other than acetate and/or nitrate.

In other embodiments of the invention, the above-described catalysts may be modified by incorporating a modifier selected from the group consisting of redox activity modifiers, acidic modifiers, and mixtures thereof into the siliceous support to alter the relative selectivity between ethanol, ethyl acetate, and acetaldehyde. Suitable redox-type activity modifiers include WO₃、MoO₃、Fe₂O₃And Cr₂O₃And the acidic modifier comprises TiO₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃. By judicious incorporation of these modifiers (judiciouus) into the siliceous support, the activity of the catalyst can be tailored to produce a more desirable relative amount distribution of catalytic hydrogenation products consistent with market fluctuations and demand for a variety of products. Typically, these materials may be included in the silicon-containing carrier in an amount of about 1-50% by weight of the silicon-containing carrier.

The metal impregnation may be carried out using any method known in the art. Typically, the support is dried at 120 ℃ and shaped into particles having a size distribution of about 0.2-0.4mm prior to impregnation. Optionally, the carrier may be pressed, crushed and sieved to the desired size distribution. Any known method of shaping the support material to the desired size distribution may be used. In a preferred method of preparing the catalyst, a dispersion of the catalytic component on a support, e.g., support particles, can be obtained using a platinum group metal component, e.g., a suitable compound and/or complex of a platinum group metal. The catalytic metal compound may be impregnated or deposited onto the support particles using a water soluble or water dispersible compound or complex of the platinum group metal. In the presence of heat and/or an application vacuumThe space-time platinum group metal component decomposes. In some cases, complete removal of the liquid is not performed until the catalyst is put into use and subjected to the high temperatures encountered during operation. Generally, aqueous solutions of soluble compounds of the platinum group metals are preferred from the economic and environmental viewpoints. For example, suitable compounds are chloroplatinic acid, amine-dissolved platinum hydroxide, palladium nitrate or chloride, sodium palladium chloride, sodium platinum chloride, and the like, although the use of halogens is preferably avoided when ethanol is the desired product. These compounds are converted to the catalytically active form of the platinum group metal or the catalytically active oxide thereof during the calcination step, or at least during the initial stage of use of the catalyst. In general, however, it is preferred to use chloride-free platinum group metal precursors, since it has been found that compounds derived from Pt (NH)₃)₄(NO₄)₂The prepared catalyst appears to exhibit improved ethanol selectivity.

Since the catalysts of the present invention are generally considered to be bimetallic, in such cases one metal acts as a promoter metal and the other metal is the primary metal. For example, in the case of a platinum tin catalyst, platinum may be considered the primary metal used to prepare the hydrogenation catalyst of the present invention, while tin may be considered the promoter metal. It should be noted, however, that sometimes such differences may be misleading, particularly in such cases where the platinum tin catalyst is selective to ethanol, the desired product approaches 0 in both the absence of tin and the absence of platinum. For convenience, it is preferred that the platinum group metal be referred to as the primary catalyst and the other metal be referred to as the promoter. This should not be taken as an indication of the underlying mechanism of catalytic activity.

The bimetallic catalyst is often impregnated in two steps. First, the "promoter" metal is added, followed by the "primary" metal. Each impregnation step is followed by drying and calcination. Bimetallic catalysts may also be prepared by co-impregnation. In the case of a promoted bimetallic catalyst as described above, sequential impregnation may be used, with the initial addition of "promoter metal followed by a second impregnation step comprising co-impregnation of the two main metals, i.e., Pt and Sn. For example, SiO₂PtSn/CaSiO on₃Can be prepared by: firstly, CaSiO₃Impregnation into SiO₂Then dissolving platinum hydroxide, palladium nitrate or palladium chloride, sodium platinum chloride, Pt (NH) with chloroplatinic acid and amine₃)₄(NO₄)₂Etc. to co-impregnate. Again, each impregnation is followed by drying and calcination. In most cases, the impregnation can be carried out using a metal nitrate solution. However, various other soluble salts that release metal ions upon calcination may also be used. Examples of other suitable metal salts for impregnation include metal acids such as perrhenic acid solutions, metal oxalates, and the like. In those cases where substantially pure ethanol is produced, it is generally preferred to avoid the use of halogenated precursors of platinum group metals, but to use nitrogen-containing amine and/or nitrate-based precursors.

The reaction can be carried out in the vapor state under a number of conditions. Preferably, the reaction is carried out in the gas phase. Reaction temperatures of, for example, from about 125 ℃ to 350 ℃, more usually from about 200 ℃ to about 325 ℃, preferably from about 225 ℃ to about 300 ℃, and most preferably from about 250 ℃ to about 300 ℃ may be used. The pressure is generally not critical to the reaction and subatmospheric, atmospheric or superatmospheric pressures may be employed. However, in most cases, the reaction pressure may be about 1 to 30 atmospheres absolute. In another aspect of the process of the invention, the hydrogenation may typically be carried out at a selected total hourly space velocity ("GHSV") at a pressure just sufficient to overcome the pressure drop across the catalyst bed, although the use of higher pressures is not limited, it being understood that 5000hr is readily available for use with the catalyst of the invention^-1And 6,500hr^-1May experience a significant pressure drop across the reactor bed.

Although the reaction consumes 2 moles of hydrogen per mole of acetic acid to produce 1 mole of ethanol, the actual molar ratio of hydrogen to acetic acid in the feed stream may vary between wide ranges, for example from about 100: 1 to 1: 100. However, such a ratio is preferably about 1: 20 to 1: 2. Most preferably, the molar ratio of hydrogen to acetic acid is about 5: 1.

The feedstock used in connection with the process of the present invention may be derived from any suitable source, including natural gas, petroleum, coal, biomass, and the like. It is well known to produce acetic acid by methanol carbonylation, acetaldehyde oxidation, ethylene oxidation, oxidative fermentation, anaerobic fermentation, and the like. As petroleum and natural gas fluctuate, becoming more or less expensive, processes for the production of acetic acid and intermediates, such as methanol and carbon monoxide, from alternative carbon sources have attracted increasing attention. In particular, when petroleum is relatively expensive compared to natural gas, it may become advantageous to produce acetic acid from synthesis gas ("syngas") derived from any suitable carbon source. For example, U.S. patent No.6,232,352 to Vidalin (the disclosure of which is incorporated herein by reference) teaches a method of retrofitting a methanol plant to make acetic acid. By retrofitting a methanol plant, the substantial capital costs associated with CO production are significantly reduced or largely eliminated for a new acetic acid plant. All or a portion of the syngas is diverted from the methanol synthesis loop and fed to a separator unit to recover CO and hydrogen, which are then used to produce acetic acid. In addition to acetic acid, this process can also be used to produce hydrogen for use in connection with the present invention.

U.S. patent No. re 35,377 to Steinberg et al, which is also incorporated herein by reference, provides a process for the production of methanol by the conversion of carbonaceous materials such as oil, coal, natural gas and biomass materials. The method comprises hydro-gasification of solid and/or liquid carbonaceous material to obtain a process gas, which process gas is steam pyrolyzed with additional natural gas to form synthesis gas. The synthesis gas is converted to methanol which can be carbonylated to acetic acid. This process also produces hydrogen gas as described above in connection with the present invention. See also U.S. Pat. No.5,821,111 to Grady et al and U.S. Pat. No.6,685,754 to Kindig et al, the disclosures of which are incorporated herein by reference, which disclose a process for converting waste biomass to syngas via gasification.

The acetic acid may be vaporized at the reaction temperature, and the vaporized acetic acid may then be fed along with hydrogen in an undiluted state or diluted with a relatively inert carrier gas such as nitrogen, argon, helium, carbon dioxide, and the like.

Alternatively, acetic acid may be withdrawn as a crude product in vapor form directly from the flash vessel of a methanol carbonylation unit of the type described in U.S. Pat. No.6,657,078 to Scates et al, which is incorporated herein by reference in its entirety. The crude vapor product can be fed directly to the reaction zone of the present invention without the need to condense acetic acid and light ends or remove water, thereby saving overall process costs.

The contact or residence time may also vary widely, depending on the amount of acetic acid, catalyst, reactor, temperature and pressure. Typical contact times range from fractions of a second to more than several hours when using catalyst systems other than fixed beds, with contact times of about 0.5 to 100 seconds being preferred, at least for gas phase reactions.

Typically, the catalyst is used in a fixed bed reactor, for example in the shape of an elongated tube or conduit, through which the reactants, typically in vapor form, pass or pass. Other reactors, such as fluidized bed or ebullating bed reactors, may be used if desired. In some cases, the hydrogenation catalyst may be used in combination with an inert material such as glass wool to adjust the pressure drop of the reactant stream through the catalyst bed and the contact time of the reactant compound with the catalyst particles.

The following examples describe the operation of the various catalysts used to prepare the process of the present invention. In all of these preparations and embodiments, when using a lower case or cursive "l", it is used to avoid the ambiguity inherent in many fonts and/or typefaces between the lower case letter "l", the number "1", and the upper case or capital letter "I", as the meaning of language arises from common usage, it being understood that it refers to the generation "liter", despite its lack of any international recognition.

Catalyst preparation (in general)

The catalyst support was dried overnight at 120 ℃ under circulating air before use. Unless otherwise mentioned, all commercial supports (i.e. SiO)₂、ZrO₂) Used at 14/30 mesh or in its original shape (1/16 inch or 1/8 inch pellets). The powdered material (i.e., CaSiO) is added after the metal is added₃) Granulation, crushing and sieving. The preparation of each catalyst is described in more detail in the following sections.

Catalyst preparation A

Preparation of 0.5 wt.% platinum and 5 wt.% tin on high purity low surface area silica

Powdered and sieved high surface area silica NPSG SS61138(100g) with a uniform particle size distribution of about 0.2mm was dried overnight at 120 ℃ in an oven under nitrogen atmosphere and then cooled to room temperature. To this were added a solution of platinum nitrate (Chempur) (0.82g) in distilled water (8ml) and a solution of tin oxalate (Alfa Aesar) (8.7g) in dilute nitric acid (1N, 43.5 ml). The resulting slurry was dried in an oven with gradual heating to 110 ℃ (> 2 hours, 10 ℃/min). The impregnated catalyst mixture was then calcined at 500 deg.C (6 hours, 1 deg.C/min).

Catalyst preparation B

Preparation of 1 wt.% platinum and 1 wt.% tin on high surface area silica

The procedure for catalyst preparation a was essentially repeated except that a solution of platinum nitrate (Chempur) (1.64g) in distilled water (16ml) and a solution of tin oxalate (AlfaAesar) (1.74g) in dilute nitric acid (1N, 8.5ml) were used.

Catalyst preparation C

Preparation of 1 wt.% platinum and 1 wt.% tin on calcium metasilicate

The procedure for catalyst preparation B was substantially repeated except that a solution of platinum nitrate (Chempur) (1.64g) in distilled water (16ml) and a solution of tin oxalate (Alfa Aesar) (1.74g) in dilute nitric acid (1N, 8.5ml) were used and calcium metasilicate was used as the catalyst support.

Catalyst preparation D

Preparation of 0.5 wt.% platinum, 0.5 wt.% tin, and 0.2 wt.% cobalt on high surface area silica

Powdered and sieved high surface area silica (100g) having a uniform particle size distribution of about 0.2mm was dried overnight at 120 ℃ in an oven under nitrogen and then cooled to room temperature. To this were added a solution of platinum nitrate (Chempur) (0.82g) in distilled water (8ml) and a solution of tin oxalate (Alfa Aesar) (0.87g) in dilute nitric acid (1N, 4.5 ml). The resulting slurry was dried in an oven with gradual heating to 110 ℃ (> 2 hours, 10 ℃/min). The impregnated catalyst mixture was then calcined at 500 deg.C (6 hours, 1 deg.C/min). To this calcined and cooled material was added a solution of cobalt nitrate hexahydrate (0.99g) in distilled water (2 ml). The resulting slurry was dried in an oven with gradual heating to 110 ℃ (> 2 hours, 10 ℃/min). The impregnated catalyst mixture was then calcined at 500 deg.C (6 hours, 1 deg.C/min).

Catalyst preparation E

Preparation of 0.5 wt.% tin on high purity low surface area silica

Powdered and sieved high purity low surface area silica (100g) of uniform particle size distribution of about 0.2mm was dried overnight at 120 ℃ in an oven under nitrogen atmosphere and then cooled to room temperature. To this was added a solution of tin oxalate (Alfa Aesar) (1.74g) in dilute nitric acid (1N, 8.5 ml). The resulting slurry was dried in an oven with gradual heating to 110 ℃ (> 2 hours, 10 ℃/min). The impregnated catalyst mixture was then calcined at 500 deg.C (6 hours, 1 deg.C/min).

Catalyst preparation F

Preparation of 2 wt.% platinum and 2 wt.% tin on high surface area silica

Powdered and sieved high surface area silica NPSG SS61138(100g) with a uniform particle size distribution of about 0.2mm was dried overnight at 120 ℃ in a circulating air oven atmosphere and then cooled to room temperature. To this was added a solution of nitrate hexahydrate (Chempur). The resulting slurry was dried in an oven with gradual heating to 110 ℃ (> 2 hours, 10 ℃/min) and then calcined. To this was added a solution of platinum nitrate (Chempur) in distilled water and a solution of tin oxalate (Alfa Aesar) in dilute nitric acid. The resulting slurry was dried in an oven with gradual heating to 110 ℃ (> 2 hours, 10 ℃/min). The impregnated catalyst mixture was then calcined at 500 deg.C (6 hours, 1 deg.C/min).

Catalyst preparation G

Preparation of 1 wt.% platinum and 1 wt.% tin on high surface area silica promoted with 5% ZnO

The procedure for catalyst preparation F was substantially repeated except that: zinc nitrate hexahydrate solution was added to the high surface area silica described in catalyst preparation F. The resulting slurry was dried in an oven with gradual heating to 110 ℃ (> 2 hours, 10 ℃/min). Then, a solution of platinum nitrate (Chempur) in distilled water and a solution of tin oxalate (Alfa Aesar) (1.74g) in dilute nitric acid (1N, 8.5ml) were subsequently added to the zinc promoted high surface area silica.

Catalyst preparation H

With 5% SnO₂Promoted preparation of 1 wt.% platinum and 1 wt.% Zn on high surface area silica

The procedure for catalyst preparation G was substantially repeated except that: mixing tin acetate (Sn (OAC)₂) Solution rather than zinc nitrate hexahydrate; and platinum nitrate Pt (NH)₃)₄(NO₃)₂(Aldrich) solution in distilled water and tin oxalate (Alfa Aesar) solution in dilute nitric acid were added to the high surface area silica.

Catalyst preparation I

Preparation of 1.5 wt.% platinum, 0.5 wt.% tin on calcium metasilicate

The procedure for catalyst preparation C above was repeated using a solution of platinum nitrate (Chempur) in distilled water and a solution of tin oxalate (Alfa Aesar) in dilute nitric acid.

Catalyst preparation J

Preparation of 1.5 wt.% platinum, 10 wt.% cobalt on high surface area silica

The procedure for catalyst preparation H above was repeated using a solution of platinum nitrate (Chempur) in distilled water, a solution of cobalt (II) nitrate hexahydrate (1.74g) in place of stannous octoate. The catalyst compositions prepared are shown in table 1, along with other catalyst compositions prepared and tested by similar procedures herein.

Catalyst preparation of K-O

SiO₂-Pt_xSn_1-x(x is more than 0 and less than 1). Five materials were prepared by varying the mole fraction of Pt while maintaining a total metal amount of 1.20mmol (Pt + Sn). The following preparations describe catalyst preparation K, i.e. SiO₂-Pt_0.5Sn_0.5(i.e., x is 0.5; the molar ratio of the two metals is equal). The metal precursor Pt (NH) is likewise used in an appropriate amount₃)₄(NO₃)₂And Sn (OAc)₂The remaining preparations were performed (i.e., x ═ 0, 0.25, 0.75, and 1.00; catalyst preparation L, M, N and O, respectively). The catalyst was prepared by: first, Sn (OAc)₂(tin acetate from Aldrich, Sn (OAc))₂) (0.1421g, 0.60mmol) was added to a vial containing 6.75ml of 1: 1 diluted glacial acetic acid (Fisher). The mixture was stirred at room temperature for 15 minutes, then 0.2323g (0.60mmol) of solid Pt (NH) were added₃)₄(NO₃)₂(Aldrich). The mixture was stirred at room temperature for a further 15 minutes and then added dropwise to 5.0g of dry SiO in a 100ml round-bottomed flask₂Catalyst support (high purity silica catalyst support HSA SS #61138, SA 250 m)²/g；SZ#61152，SA＝156m²(ii)/g; Saint-Gobain NorPro). The metal solution was continuously stirred until all the Pt/Sn mixture was added to the SiO₂The catalyst support was simultaneously rotated after each addition of the metal solution. After the addition of the metal solution was complete, the flask containing the impregnated catalyst was maintained at room temperature while stillStanding for 2 hours. The flask was then connected to a rotary evaporator (bath temperature 80 ℃) and evacuated until dry while slowly rotating the flask. The material was then further dried overnight at 120 ℃ and then calcined using the following temperature program: 25 → 160 ℃/slope 5.0 deg/min; keeping for 2.0 hours; 160 → 500 deg.C/slope of 2.0 deg/min; the holding time was 4 hours. Yield: 5.2g of dark grey material.

Catalyst preparation P

SiO₂-CaSiO₃(5) -Pt (3) -Sn (1.8). The material is prepared by firstly mixing CaSiO₃(Aldrich) was added to SiO₂The catalyst support was then prepared as previously described with the addition of Pt/Sn. First, CaSiO₃(. ltoreq.200 mesh) aqueous suspension by adding 0.52g of this solid to 13ml of deionized water, followed by 1.0ml of colloidal SiO₂(15 wt% solution, NALCO). The suspension was stirred at room temperature for 2 hours and then 10.0g SiO was added using incipient wetness impregnation technique₂Catalyst support (14/30 mesh). After standing for 2 hours, the material was evaporated to dryness, then dried under circulating air at 120 ℃ overnight and calcined at 500 ℃ for 6 hours. 0.6711g (1.73mmol) of Pt (NH) were then used₃)₄(NO₃)₂And 0.4104g (1.73mmol) of Sn (OAc)₂SiO as per above₂-Pt_xSn_1-xMaterials the procedure described for the preparation of all SiO₂-CaSiO₃The material was used for Pt/Sn metal impregnation. Yield: 11.21g of dark grey material.

Catalyst preparation Q

CaSiO₃-Pt (1) -Sn (1). To a 100ml round bottom flask containing a Teflon coated magnetic stir bar was added 40ml of 1.0M NHO₃Followed by addition of 0.2025g (0.52mmol) of solid Pt (NH)₃)₄(NO₃)₂. With stirring the Pt complex was dissolved and then 0.2052g (0.87mmol) of solid Sn (OAc) were added₂. Next, 10.0g of CaSiO was added with stirring₃(less than or equal to 200 meshes); the mixture was then heated to 80 ℃ and stirred at this temperature for 2 hours. Then useThe suspension was evacuated to dryness on a rotary evaporator (bath temperature 80 ℃) and the solid was transferred to a ceramic evaporating dish and dried overnight at 120 ℃ under circulating air. After calcination (25 ℃ → 160 ℃/slope 5.0 deg.f/min; hold for 2.0 hours; 160 → 500 ℃/slope 2.0 deg.f/min; hold for 4 hours), pressing is carried out under pressure, in particular with a force of 40,000lbs, for 15 minutes, the material is pressed, granulated, and crushed and sieved to 14/30 mesh. Yield: 9.98g of tan material.

Catalyst preparation R

SiO₂-TiO₂(10) -Pt (3) -Sn (1.8). Preparation of TiO as follows₂-a modified silica support. 4.15g (14.6mmol) of Ti { OCH (CH)₃)₂}₄The solution in 2-propanol (14ml) was added dropwise to 10.0g SiO in a 100ml round bottom flask₂Catalyst support (1/16 inch extrudates). The flask was allowed to stand at room temperature for 2 hours, and then evacuated using a rotary evaporator (bath temperature 80 ℃) until dry. Next, 20ml of deionized water was slowly added to the flask and the material was allowed to stand for 15 minutes. The resulting water/2-propanol was then removed by filtration and the addition of H was repeated₂O2 times. The final material was dried overnight at 120 ℃ under circulating air, followed by calcination at 500 ℃ for 6 hours. 0.6711g (1.73mmol) of Pt (NH) were then used₃)₄(NO₃)₂And 0.4104g (1.73mmol) of Sn (OAc)₂SiO as per above₂-Pt_xSn_1-xMaterials the procedure described for the preparation of all SiO₂-TiO₂The material was used for Pt/Sn metal impregnation. Yield: 11.98g of dark gray 1/16 inch extrudate.

Catalyst preparation S

SiO₂-WO₃(10) -Pt (3) -Sn (1.8). WO is prepared as follows₃-a modified silica support. 1.24g (0.42mmol) of (NH)₄)₆H₂W₁₂O₄₀·nH₂A solution of O (AMT) in deionized water (14ml) was added dropwise to 10.0g SiO in a 100ml round bottom flask₂NPSGSS61138 catalyst supportBody (SA 250 m)²1/16 inch extrudates). The flask was left to stand at room temperature for 2 hours, and then evacuated using a rotary evaporator (bath temperature 80 ℃) until dry. The resulting material was dried overnight at 120 ℃ under circulating air, followed by calcination at 500 ℃ for 6 hours. 0.6711g (1.73mmol) of Pt (NH) were then used₃)₄(NO₃)₂And 0.4104g (1.73mmol) of Sn (OAc)₂SiO as per above₂-Pt_xSn_1-xMaterials the procedure described is to combine all (pale yellow) SiO₂-WO₃The material was used for Pt/Sn metal impregnation. Yield: 12.10g of dark gray 1/16 inch extrudate.

Catalyst preparation T

(H-ZSM-5) -Pt (3) -Sn (1.8). The material is passed through H-ZSM-5 (from NH)₄ZSM-5 was prepared by calcination at 550 c for 8 hours in air). 0.6711g (1.73mmol) of Pt (NH)₃)₄(NO₃)₂And 0.4104g (1.73mmol) of Sn (OAc)₂Was prepared by adding the components to 40ml of 1: 1 diluted acetic acid in a 100ml round bottom flask and stirring the mixture at room temperature for 15 minutes. Next, 10.0g of solid, finely powdered H-ZSM-5 was added to the solution with stirring, and the mixture was stirred at room temperature for another 2 hours. The flask was then evacuated using a rotary evaporator (bath temperature 80 ℃) until dry and the resulting material was dried overnight at 120 ℃ under circulating air. After calcination (250 ℃ → 160 ℃/slope 5.0 deg.f/min; hold for 2.0 hours; 160 → 500 ℃/slope 2.0 deg.f/min; hold for 4 hours), the material was pressed, granulated, crushed and sieved to 14/30 mesh. Yield: 9.55g of grey material.

Catalyst preparation U

SiO₂-Re_xPd_1-x(x is more than 0 and less than 1). Five materials were prepared by varying the mole fraction of Re while maintaining a total metal amount of 1.20mmol (Re + Pd). The following preparations describe SiO₂-Re_0.5Pd_0.5(i.e., x is 0.5; the molar ratio of the two metals is equal). Is used as suchAppropriate amount of metal precursor NH₄ReO₄And Pd (NO)₃)₂The remaining preparations were performed (i.e., x ═ 0, 0.25, 0.75, and 1.00). The metal solution is prepared by: first NH₄ReO₄(0.1609g, 0.60mmol) was added to a vial containing 6.75ml of deionized water. The mixture was stirred at room temperature for 15 minutes, then 0.1154g (0.60mmol) of solid Pd (NO) were added₃)₂. The mixture was stirred at room temperature for a further 15 minutes and then added dropwise to 5.0g of dry SiO in a 100ml round-bottomed flask₂Catalyst support (14/30 mesh). After the addition of the metal solution was completed, the flask containing the impregnated catalyst was maintained at room temperature for 2 hours. The flask was then connected to a rotary evaporator (bath temperature 80 ℃) and evacuated until dry. SiO as above₂-Pt_xSn_1-xAll other operations (drying, calcination) were carried out as described for the material, see above. Yield: 5.1g of brown material.

Catalyst preparation V

SiO₂-CaSiO₃(5) -Re (4.5) -Pd (1). According to SiO₂-CaSiO₃(5) Preparation of SiO as described for-Pt (3) -Sn (1.8)₂-CaSiO₃(5) Modified catalyst support, see above. Then by using a catalyst containing NH₄ReO₄And Pd (NO)₃)₂By impregnating SiO with an aqueous solution of₂-CaSiO₃(5) (1/16 inch extrudates) Re/Pd catalyst was prepared. The metal solution is prepared by first reacting NH₄ReO₄(0.7237g, 2.70mmol) was added to a vial containing 12.0ml of deionized water for preparation. The mixture was stirred at room temperature for 15 minutes, then 0.1756g (0.76mmol) of solid Pd (NO) were added₃)₂. The mixture was stirred at room temperature for a further 15 minutes and then added dropwise to 10.0g of dry SiO in a 100ml round-bottomed flask₂-(0.05)CaSiO₃In the catalyst support. After the addition of the metal solution was completed, the flask containing the impregnated catalyst was maintained at room temperature for 2 hours. SiO as above₂-Re_xPd_1-xAll other treatments (drying, calcination) were carried out as described for the material, see above.Yield: 10.9g of brown material.

Catalyst preparation W

CaSiO₃-Re (5) -Pd (2.5). The material is prepared by CaSiO₃The slurry (powder, less than or equal to 200 meshes) is soaked for preparation. 0.6169g (2.30mmol) of NH₄ReO₄And 0.5847g (2.53mmol) of Pd (NO)₃)₂Was prepared by adding the components to 40ml of deionized water in a 100ml round bottom flask and stirring the mixture at room temperature for 15 minutes. Next, 10.0g of CaSiO in the form of a solid fine powder was stirred₃Added to the solution and the mixture stirred at room temperature for an additional 2 hours. The flask was then evacuated using a rotary evaporator (bath temperature 80 ℃) until dry and the resulting material was dried overnight at 120 ℃ under circulating air. SiO as above₂-RexPd_1-xAll other treatments (drying, calcination) were carried out as described for the material, see above. The final material was pressed, granulated, and crushed and sieved to 14/30 mesh using a press that applied 40,000lbs of force for 15 minutes. Yield: 10.65g of brown material.

Catalyst preparation X

SiO₂-Co (10) -Pt (1). The material is prepared by using a catalyst containing Co (NO)₃)₂·6H₂O and Pt (NH)₃)₄(NO₃)₂By dipping HSA SiO in an aqueous solution of₂(14/30 mesh) was prepared. The metal solution is prepared by first adding Co (NO)₃)₂·6H₂O (5.56g, 19.1mmol) was prepared by adding to a vial containing 12.0ml of deionized water. The mixture was stirred at room temperature for 15 minutes, then 0.2255g (0.58mmol) of solid Pt (NH) were added₃)₄(NO₃)₂. The mixture was stirred at room temperature for a further 15 minutes and then added dropwise to 10.0g of dry SiO in a 100ml round-bottomed flask₂Catalyst support (14/30 mesh). After the addition of the metal solution was completed, the flask containing the impregnated catalyst was maintained at room temperature for 2 hours. SiO as above₂-Pt_xSn_1-xMaterial said to carry out allIt was treated (dried, calcined), see above. Yield: 11.35g of black material.

Catalyst preparation Y

CaSiO₃-Co (10) -Pt (1). The material is prepared by CaSiO₃The slurry (powder, less than or equal to 200 meshes) is soaked for preparation. 5.56g (19.1mmol) of Co (NO)₃)₂·6H₂O and 0.2255g (0.58mmol) of Pt (NH)₃)₄(NO₃)₂Was prepared by adding the components to 40ml of deionized water in a 100ml round bottom flask and stirring the mixture at room temperature for 15 minutes. Next, 10.0g of CaSiO in the form of a solid fine powder was stirred₃Is added to the solution. The mixture was then heated to 65 ℃ and stirred at this temperature for a further 2 hours. The flask was then evacuated using a rotary evaporator (bath temperature 80 ℃) until dry and the resulting material was dried overnight at 120 ℃ under circulating air. SiO as above₂All other treatments (drying, calcination) as described for the-Co (10) -Pt (1) materials, see above. The final material was pressed under pressure, granulated, and crushed and sieved to 14/30 mesh. Yield: 10.65g of black material.

Catalyst preparation Z

ZrO₂-Co (10) -Pt (1). The material is prepared by using a catalyst containing Co (NO)₃)₂·6H₂O and Pt (NH)₃)₄(NO₃)₂Impregnating the aqueous solution of (a) with ZrO₂(SZ 61152, Saint-Gobain NorPro, 14/30 mesh). The metal solution is prepared by first adding Co (NO)₃)₂·6H₂O (5.56g, 19.1mmol) was prepared by adding to a vial containing 5.0ml of deionized water. The mixture was stirred at room temperature for 15 minutes, then 0.2255g (0.58mmol) of solid Pt (NH) were added₃)₄(NO₃)₂. The mixture was stirred at room temperature for another 15 minutes, and then added dropwise to 10.0g of dried ZrO in a 100ml round-bottom flask₂Catalyst support (14/30 mesh). After the addition of the metal solution was complete, the flask containing the impregnated catalyst was maintained in the chamberThe mixture was allowed to stand at room temperature for 2 hours. SiO as above₂All other treatments (drying, calcination) as described for Co (10) -Pt (1), see above. Yield: 11.35g of black material.

Catalyst preparation of AA

SiO₂-CaSiO₃(2.5)-Pt(1.5)-Sn(0.9)。

The material is SiO as described above₂-CaSiO₃(5) -Pt (3) -Sn (1.8) the use of 0.26gCaSiO₃0.5ml of colloidal SiO₂(15% by weight solution, NALCO), 0.3355g (0.86mmol) of Pt (NH)₃)₄(NO₃)₂And 0.2052g (0.86mmol) of Sn (OAc)₂The preparation is carried out. Yield: 10.90g of dark grey material.

Catalyst preparation BB

TiO₂-CaSiO₃(5)-Pt(3)-Sn(1.8)。

The material is prepared by firstly mixing CaSiO₃Is added to TiO₂The catalyst (anatase, 14/30 mesh) support was then prepared as described previously with the addition of Pt/Sn. First, CaSiO₃(. ltoreq.200 mesh) aqueous suspension by adding 0.52g of this solid to 7.0ml of deionized water, followed by 1.0ml of colloidal SiO₂(15 wt% solution, NALCO). The suspension was stirred at room temperature for 2 hours and then 10.0g TiO was added using incipient wetness impregnation technique₂Catalyst support (14/30 mesh). After standing for 2 hours, the material was evaporated to dryness, then dried under circulating air at 120 ℃ overnight and calcined at 500 ℃ for 6 hours. 0.6711g (1.73mmol) of Pt (NH) were then used₃)₄(NO₃)₂And 0.4104g (1.73mmol) of Sn (OAc)₂SiO as per above₂-Pt_xSn_1-xProcedure described for materials all TiO₂-CaSiO₃The material was used for Pt/Sn metal impregnation. Yield: 11.5g of light grey material.

Catalyst preparation CC

KA160-Pt(3)-Sn(1.8)。

The material has previously been SiO₂-Pt_xSn_1-xThe passing KA160 catalyst carrier (SiO)₂-(0.05)Al₂O₃Sud Chemie, 14/30 mesh) was prepared by incipient wetness impregnation, see above. The metal solution is prepared by first reacting Sn (OAc)₂(0.2040g, 0.86mmol) was added to a vial containing 4.75ml of 1: 1 diluted glacial acetic acid. The mixture was stirred at room temperature for 15 minutes, then 0.3350g (0.86mmol) of solid Pt (NH) were added₃)₄(NO₃)₂. The mixture was stirred at room temperature for an additional 15 minutes and then added dropwise to 5.0g of dry KA160 catalyst support (14/30 mesh) in a 100mL round bottom flask. As above SiO₂-Pt_xSn_1-xAll other treatments, drying and calcination are performed as described. Yield: 5.23g of tan material.

Catalyst preparation DD

KA160-CaSiO₃(8)-Pt(3)-Sn(1.8)。

The material is prepared by firstly mixing CaSiO₃Was added to the KA160 catalyst support, followed by Pt/Sn addition as described above for KA160-Pt (3) -Sn (1.8). First, CaSiO₃(. ltoreq.200 mesh) aqueous suspension by adding 0.42g of this solid to 3.85ml of deionized water, followed by 0.8ml of colloidal SiO₂(15 wt% solution, NALCO). The suspension was stirred at room temperature for 2 hours and then 5.0g of KA160 catalyst support (14/30 mesh) was added using incipient wetness impregnation technique. After standing for 2 hours, the material was evaporated to dryness, then dried under circulating air at 120 ℃ overnight and calcined at 500 ℃ for 6 hours. 0.3350g (0.86mmol) of Pt (NH) were then used₃)₄(NO₃)₂And 0.2040g (0.86mmol) of Sn (OAc)₂SiO as per above₂-Pt_xSn_1-xMaterials the procedure is to mix all KA160-CaSiO₃The material was used for Pt/Sn metal impregnation. Yield: 5.19g of a tan material.

Gas chromatography (gc) analysis of the product

Analysis of the product was performed by online GC. The reactants and products were analyzed using a three-channel integrated GC equipped with 1 Flame Ionization Detector (FID) and 2 Thermal Conductivity Detectors (TCD).

The front channel was equipped with FID and CP-Sil 5(20m) + WaxFFap (5m) columns and used for quantification: acetaldehyde; ethanol; acetone; methyl acetate; vinyl acetate; ethyl acetate; acetic acid; ethylene glycol diacetate; ethylene glycol; ethylidene diacetate; and paraldehyde.

The intermediate channel was equipped with TCD and Porabond Q columns and used for quantization: CO 2₂(ii) a Ethylene; and ethane.

The back channel was equipped with TCD and Molsieve 5A columns and used for quantification: helium gas; hydrogen gas; nitrogen gas; methane; and carbon monoxide.

Prior to the reaction, the retention times of the different components were determined by spiking with individual compounds and the GC was calibrated with a calibration gas of known composition or with a liquid solution of known composition. This allows the response factors of the individual components to be determined.

Example 1

In a tubular reactor made of stainless steel having an inner diameter of 30mm and capable of being raised to a controlled temperature, 50ml of the catalyst prepared as described in the above catalyst preparation C was placed. The total length of the catalyst bed after loading was approximately about 70 mm.

Feed liquid baseEssentially consisting of acetic acid. Vaporizing the reaction feed liquid at a temperature of 250 ℃ and a pressure of 100psig and 2500hr with hydrogen and helium as carrier gas^-1Is charged to the reactor at a mean total Gas Hourly Space Velocity (GHSV). The feed stream contains from about 6.1 to about 7.3 mole percent acetic acid and from about 54.3 to about 61.5 mole percent hydrogen. A portion of the vapor effluent from the reactor was passed through a gas chromatograph for analysis of the contents of the effluent. The selectivity to ethanol at 85% acetic acid conversion was 93.4%.

The catalysts utilized were 1 wt.% platinum and 1 wt.% tin on silica prepared according to procedure of catalyst preparation a.

Example 2

The catalyst utilized was 1 wt.% platinum and 1 wt.% tin on calcium silicate prepared according to the procedure of example C.

At 250 deg.C and 22bar pressure for 2,500hr^-1The procedure given in example 1 was essentially repeated with a feed stream of vaporized acetic acid and hydrogen at average total Gas Hourly Space Velocity (GHSV). A portion of the vapor effluent was passed through a gas chromatograph for analysis of the contents of the effluent. The acetic acid conversion rate is more than 70 percent, and the ethanol selectivity is 99 percent.

Comparative example 1

The catalyst utilized was 1 weight percent tin on low surface area high purity silica prepared according to the procedure of example E.

At 250 deg.C and 22bar pressure for 2,500hr^-1The procedure given in example 1 was essentially repeated with a feed stream of vaporized acetic acid and hydrogen at average total Gas Hourly Space Velocity (GHSV). A portion of the vapor effluent was passed through a gas chromatograph for analysis of the contents of the effluent. The acetic acid conversion rate is less than 10 percent, and the ethanol selectivity is less than 1 percent.

Example 3

The procedure of example 2 was repeated using various catalysts at the temperatures given in table 2, with the percentages of carbon monoxide (CO), acetaldehyde (AcH) and ethane and ethyl acetate (EtOAc) in the product given in table 2; selectivity and yield of ethanol (EtOH) and percent conversion of acetic acid (HOAc) (MCD p.4). Always, H₂The molar ratio to acetic acid was maintained at 5: 1. For convenience, the results of examples 1, 2 and comparative example 1 are also included in table 2. Generally, when it is desired to produce ethanol as the major product, the selectivity to ethanol is desired to be approximately greater than 80%; selectivity to ethyl acetate is desirably less than 5%, preferably less than 3%.

Example 4

At about 6570hr^-1At a pressure of 200psig and at a space velocity of about 160sccm/minH₂: hydrogen to acetic acid ratio of HOAc at 0.09g/min (about 60sccm/min N for hydrogen)₂Dilution) vaporized acetic acid and hydrogen are passed over a hydrogenation catalyst of the present invention comprised of a catalyst having a surface area of about 250m²2 wt% Pt and 2 wt% Sn per g of high surface area silica (NPSG SS 61138). The temperature was increased at about 50 hours, 70 hours, and 90 hours as shown in figures 1 and 2, where in figure 1 the grams of product (ethanol, acetaldehyde, and ethyl acetate) shown per kilogram of catalyst per hour are shownThe selectivity of the catalyst to various products is shown in figure 2, where the upper line represents the yield or selectivity of ethyl acetate, the middle line represents ethanol, and the lower line represents acetaldehyde. It is believed to be particularly evident that the acetaldehyde yield and selectivity are low. The results are summarized in the following summary of data.

Data summarization

Example 5

Using a catalyst having 2 wt% Pt supported on a catalyst comprising high surface area silica SS61138 pellets from Saint-Gobain NorPro; 2 wt% Sn catalyst at the indicated temperature and pressure of 100psig given in Table 2 for 2500hr^-1The procedure set forth in example 1 was substantially repeated with average total Gas Hourly Space Velocity (GHSV) feed streams of vaporized acetic acid, hydrogen and helium. The resulting feed stream contained about 7.3 mole percent acetic acid and about 54.3 mole percent hydrogen. A portion of the vapor effluent was passed through a gas chromatograph for analysis of the contents of the effluent. The results are presented in table 1.

TABLE 3

The results of example 5 are summarized in fig. 3, which demonstrates that the relative insensitivity of the catalyst to temperature variations makes the catalyst well suited for use in so-called adiabatic reactors, where the temperature across the catalyst bed can vary widely due to the low and uneven rate of heat removal from the reactor.

Example 6

SiO was investigated by₂-Pt_xSn_1-xIn catalyst [ Sn]/[Pt]Influence of the molar ratio: (i) at constant metal loading ([ Pt ]]+[Sn]1.20mmol), and (ii) as a function of the reduction temperature. A Pt mole fraction of 0.5 (i.e. [ Sn ]) was observed]/[Pt]1.0) for acetic acid conversion and for ethanol. In [ Sn ]]/[Pt]1.0) in favor of ethanol the selectivity to ethyl acetate changes dramatically. At Pt mole fractions of 25% or 75%, ethyl acetate was observed as the main product. The presence of equimolar ratios of Pt and Sn appears to be preferred for the improvement of acetic acid conversion and selectivity to ethanol, see fig. 4A-C.

At a temperature of 250 ℃; GHSV of 6570h^-1(ii) a The reaction time was 12 hours and vaporized acetic acid (0.09g/min HOAc) and hydrogen (160sccm/min H)₂；60sccm/min N₂) Passing through the hydrogenation catalyst of the invention, the hydrogenation catalyst comprising a catalyst having a surface area of about 250m²Pt and Sn per g of high surface area silica. In this example 6, the amount of metal (Pt + Sn) was kept constant and the mass fraction of platinum was varied between 0 and 1. Fig. 4A-4C depict the respective selectivity, activity and yield of the catalysts. From this example, it can be appreciated that the maximum values of selectivity, activity and yield occur when the mass fraction of platinum is about 0.5, i.e. the amount of platinum by weight is substantially equal to the amount of tin in the catalyst.

Example 7

Passing vaporized acetic acid and hydrogen over a hydrogenation catalyst of the present invention comprising a catalyst having a surface area of about 250m at a hydrogen to acetic acid molar ratio of about 5: 1 at a temperature of about 225 deg.C²3 wt.% Pt, 1.5 wt.% Sn and 5 wt.% CaSiO as promoter on high purity high surface area silica/g₃. FIGS. 5A and 5B depict the catalyst at the initial stage of its lifeCatalyst selectivity and productivity as a function of run time during the run. From the results of this example reported in fig. 6A and 6B, it can be appreciated that selectivity activities higher than 90% and yields higher than 500g of ethanol per kg of catalyst per hour can be obtained.

Example 8

The procedure of example 8 was repeated at a temperature of about 250 ℃ (the same catalyst. Fig. 7A-7B depict catalyst selectivity and productivity as a function of run time during the initial phase of catalyst life. From the results of this example reported in fig. 7A and 7B, it can be appreciated that at this temperature still a selectivity activity higher than 90% can be obtained but at the same time a yield higher than 800g of ethanol per kg of catalyst per hour is obtained.

Example 9

To investigate the temperature sensitivity for the reduction of bimetallic platinum and tin precursors to catalytic species, SiO was determined by optimizing Pt/Sn in a separate experiment at 225-500 deg.C₂-(Pt_0.5Sn_0.5) Catalyst activation the effect of reduction temperature was investigated, see below. In 4 experiments, the material was activated at 280, 350, 425 and 500 ℃ for 4 hours under flowing hydrogen, followed by acetic acid reduction at a reaction temperature of 250 ℃. (10 mol% of H was used)₂/N₂The mixture (275sccm/min) was subjected to catalyst activation at ambient pressure using the following temperature program: RT-reduction temperature (225 ℃ C.) and gradient of 2 deg.g/min; held for 4.0 hours and then reduced (or raised if necessary) to 250 ℃ for reduction of HOAc. Furthermore, the material activated at 225 ℃ was investigated in the hydrogenation of HOAc at reaction temperatures of 225 and 250 ℃. No significant changes in selectivity to ethanol and ethyl acetate were observed throughout the entire temperature range, including for catalysts activated at 225 ℃ for reaction temperatures of 225 ℃ and 250 ℃. It is noted that transitions were observed for catalysts activated at lower, 225 and 280 ℃ reduction temperaturesThe chemical efficiency (and the yield) is obviously improved. The reduction in conversion at higher reduction temperatures may be attributed to sintering of the metal particles. (see fig. 7A and 7B) the composition of the metal particles (i.e. PtSn alloy) appeared to remain unchanged since no change in selectivity was observed. The results of this example are depicted in FIGS. 3A-3C.

Various other products were detected in these examples, including acetaldehyde, ethanol, ethyl acetate, ethane, carbon monoxide, carbon dioxide, methane, isopropanol, acetone, and water.

Example 10

The catalytic performance of each catalyst was evaluated using 2.5ml of the solid catalyst of the catalysts shown in table 4 in the catalytic hydrogenation of acetic acid. In each case, the catalyst particles had a size of 14/30 mesh and were diluted 1: 1v/v with 14/30 mesh quartz chips. In each run, over a range (span) of 24 hours run Time (TOS), an operating pressure of 200psig (14bar) with a feed rate of 0.09g/min acetic acid; 120sccm/min hydrogen; 60sccm/min of nitrogen gas for 6570h^-1Total gas hourly space velocity. The results are shown in table 4.

Table 4. catalytic activity of various supported metal catalysts in HOAc catalytic hydrogenation. Reaction conditions are as follows: 2.5ml of solid catalyst (14/30 mesh, 1: 1 dilution (v/v with quartz chips, 14/30 mesh), p 200psig (14bar), 0.09g/min HOAc; 120sccm/min H₂；60sccm/min N₂；GHSV＝6570h^-1(ii) a 24 hours run Time (TOS).

Example 11

Catalyst stability: SiO 2₂-CaSiO₃(5) -Pt (3) -Sn (1.8). Evaluation of SiO in the reaction time of more than 100 hours at constant temperature (260 ℃ C.)₂-CaSiO₃(5) Catalytic performance and initial stability of Pt (3) -Sn (1.8). Only minor changes in catalyst performance and selectivity were observed over a total reaction time of over 100 hours. Acetaldehyde appears to be the only by-product and its concentration (about 3 wt%) remains largely unchanged during the course of the experiment. A summary of catalyst productivity and selectivity is provided in fig. 5A and 5B. The effect of reaction temperature on product selectivity was investigated in separate experiments over a total reaction time of 125 hours, see above.

Example 12

2.5ml of solid catalyst (14/30 mesh, 1: 1 dilution (v/v with quartz chips, 14/30 mesh) was used, at a pressure of 200psig, feed rate of 0.09g/min HOAc; 160sccm/minH₂；60sccm/min N₂；GHSV＝6570h^-1In a typical range of operating conditions, the use of 5% CaSiO in the hydrogenation of acetic acid was investigated by producing mainly acetaldehyde, ethanol, ethyl acetate by hydrogenation and esterification reactions in a fixed bed continuous reactor system operating at 225 ℃ for a duration of 15 hours₃Stable high purity high surface area SiO₂3% Pt above: yield and selectivity of 1.5% Sn. The results are given in fig. 6A and 6B.

Example 13

2.5ml of solid catalyst (14/30 mesh, 1: 1 dilution (v/v, with quartz chips, 14/30 mesh) were used, 0.09g/min acetic acid was fed at a pressure of 200psig (14bar), with 160sccm/min hydrogen and 60sccm/min nitrogen as diluent (solvent), at a temperature of 250 ℃, GHSV 6570h^-1(ii) a Or a reaction time of 12 hours,by varying at constant metal loading ([ Pt ]]+[Sn]1.20mmol) of Re in SiO₂Yield and selectivity of Re and Pd in (with Re modified between catalysts)_xPd_(1-x)Molar ratio of (a). Although the maximum conversion of acetic acid was observed at a mole fraction of Re of about 0.6, ethanol became the major product only at a mole fraction of Re of about 0.78. The molar ratio between Re and Pd (expressed as "Re")₇Pd₂") the selectivity to ethyl acetate varies over a narrow range in favor of ethanol. Importantly, and as shown by the Pd/Sn series described above, the presence of a specific ratio of two metals appears to be a key structural requirement for specific product selectivity, namely at [ Re ]]/[Re+Pd]Selective transfer to ethanol at 0.78, reference is made to fig. 8, 9 and 10, given in the same format as fig. 4A-C, except that X is_i(Re) represents the mass fraction of rhenium in the catalyst. However, in contrast to Pt/Sn materials, the maximum conversion of acetic acid and selectivity to ethanol did not match these materials, and favorable selectivity to ethanol was only observed at low HOAc conversions. Thus, referring to fig. 8, the maximum yield was observed for ethyl acetate, but not for ethanol. Furthermore, CaSiO was used₃The formation of hydrocarbons (methane and ethane; 5.3 and 2.4 wt% of them, respectively) was observed with the-Re (5) -Pd (2.5) catalyst at a conversion of acetic acid of about 30% and a reaction temperature of only 225 ℃. While higher conversions of acetic acid may most likely be obtained by increasing the reaction temperature, it will also be possible to increase the amount of hydrocarbons, thus limiting the overall efficiency of the Re/Pd based catalytic system.

Example 14

Used in SiO₂Initial catalyst screening of the silica-on-platinum (1%) cobalt catalyst (Co loading of 10 wt%) resulted in high acetic acid conversion and selectivity to ethanol of about 80%. Referring to FIGS. 11 and 12, wherein selectivity and activity are as previously defined, results are shown as squares for ethanol, circles for ethyl acetate, diamonds for acetaldehyde, and triangles for ethaneAnd (4) showing. However, it appears that the catalyst deteriorates as the acetic acid selectivity drops from about 80% to 42% over the course of 9 hours of reaction time. In addition, significant changes in yield were observed, as well as a decrease in ethanol selectivity with increasing selectivity to ethyl acetate and acetaldehyde. Similar results were obtained with 10% cobalt supported on silica.

Example 15

At a temperature of 250 ℃; GHSV of 6570h^-1(ii) a Vaporized acetic acid (0.09g/min HOAc) and hydrogen (160sccm/min H) at 200psig for 12 hours of reaction time₂；60sccm/min N₂) Passing through the hydrogenation catalyst of the present invention, the hydrogenation catalyst comprised 3 wt.% Pt and 1.8 wt.% Sn on a support comprising a hydrogen-form ZSM-5 molecular sieve. Diethyl ether was obtained with a selectivity of 96% and a yield of 2646g/kg/h, with 4% ethyl acetate, 78% acetic acid remaining unreacted.

Example 16

At 275 ℃; GHSV of 6570h^-1(ii) a Vaporized acetic acid (0.09g/min HOAc) and hydrogen (160sccm/min H) at 200psig for 12 hours of reaction time₂；60sccm/min N₂) Passing through the hydrogenation catalyst of the present invention, the hydrogenation catalyst comprises 2 wt.% Pt and 1 wt.% Sn on a support comprising high surface area graphite. The selectivity of ethyl acetate was 43%, the selectivity of ethanol was 57%, the yield of ethyl acetate was 66g/kg/hr, the yield of ethanol was 88g/kg/hr, and the conversion of acetic acid was 12%.

Although the present invention has been described in detail, various modifications within the spirit and scope of the invention will be apparent to those skilled in the art. In view of the above discussion, relevant knowledge in the art and references discussed above in relation to the background and detailed description, the disclosures of which are incorporated herein by reference in their entirety, other exemplifications are not deemed necessary. Furthermore, it is to be understood that various aspects of the invention as well as various portions of various embodiments and features recited below and/or in the appended claims may be combined or interchanged either in part or in whole. Furthermore, those skilled in the art will recognize that the foregoing description is by way of example only, and is not intended to limit the present invention.

Thus in order to provide an acetic acid based hydrogenation product, a novel process and catalyst are provided according to the present invention.

For example, embodiment #1 is a process for producing ethanol by reducing acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a gas phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst comprising platinum and tin dispersed on a silicon-containing support, wherein the amount and oxidation state of platinum and tin, and the ratio of platinum to tin, and the silicon-containing support are selected, configured, and controlled such that: (i) converting at least 80% of the converted acetic acid to ethanol; (ii) less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, and mixtures thereof; and when the pressure is 2atm, the temperature is 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 168 hours, the catalyst activity decreases by less than 10%.

Embodiment #2 is the method of embodiment #1, wherein the hydrogenation catalyst consists essentially of platinum and tin dispersed on a silicon-containing support and the silicon-containing support is a modified silicon-containing support comprising an effective amount of a support modifier selected from the group consisting of: (i) an alkaline earth metal oxide, (ii) an alkali metal oxide, (iii) an alkaline earth metal metasilicate, (iv) an alkali metal metasilicate, (v) zinc oxide, (vi) zinc metasilicate and (vii) a precursor of any of (i) - (vi), and any mixture of (i) - (vii).

Embodiment #3 is the method of embodiment #2, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #4 is the method of embodiment #2, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #5 is the process of embodiment #3, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #6 is the method of embodiment #2, wherein the support modifier is selected from the group consisting of sodium, potassium, magnesium, calcium, and zinc metasilicates, as well as precursors thereof and mixtures of any of the foregoing.

Embodiment #7 is the method of embodiment #5, wherein (a) the platinum is present in an amount from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #8 is the process of embodiment #6, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #9 is the method of embodiment #2, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #10 is the method of embodiment #9, wherein: (a) platinum is present in an amount of 0.5% to 5% by weight of the catalyst; (b) the tin is present in an amount of at least 0.5-10%.

Embodiment #11 is the process of embodiment #10, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #12 is the method of embodiment #2, wherein the support modifier is selected from the group consisting of metasilicates of magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #13 is the method of embodiment #12, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #14 is the process of embodiment #12, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #15 is the method of embodiment #2, wherein the support modifier is selected from the group consisting of calcium metasilicate, a precursor of calcium metasilicate, and a mixture of calcium metasilicate and a precursor thereof.

Embodiment #16 is the method of embodiment #15, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #17 is the process of embodiment #16, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #18 is the method of embodiment #2, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #19 is the method of embodiment #16, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #20 is the method of embodiment #18, wherein the support has a surface area of at least about 100m²/g。

Embodiment #21 is the process of embodiment #20, wherein the molar ratio of tin to platinum group metal is from about 1: 2 to about 2: 1.

Embodiment #22 is the process of embodiment #20, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #23 is the method of embodiment #20, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #24 is the method of embodiment #2, wherein the support has a surface area of at least about 150m²/g。

Embodiment #25 is the method of embodiment #24, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; (b) the tin is present in an amount of at least 0.5-5%.

Embodiment #26 is the method of embodiment #24, wherein the carrier comprises at least about 1% to about 10% by weight calcium silicate.

Embodiment #27 is the process of embodiment #24, wherein the molar ratio of tin to platinum is from about 1: 2 to about 2: 1.

Embodiment #28 is the method of embodiment #24, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #29 is the method of embodiment #24, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #30 is the method of embodiment # 2; wherein the support has a surface area of at least about 200m²/g。

Embodiment #31 is the process of embodiment #30 wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #32 is method #30 of an embodiment wherein the molar ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #33 is the process of embodiment #30 wherein the molar ratio of tin to platinum is from about 9: 10 to about 10: 9.

Embodiment #34 is the method of embodiment #33, wherein the modified silicon containing support has a surface area of at least about 250m²/g。

Embodiment #35 is the process of embodiment #2, which is carried out at a temperature of about 250 ℃ to 300 ℃, wherein (a) the modified siliceous support has a surface area of at least about 250m²(ii)/g; (b) platinum is present in the hydrogenation catalyst in an amount of at least about 0.75 wt.%; (c) the molar ratio of tin to platinum is from about 5: 4 to about 4: 5; (d) the modified siliceous support comprises a purity of at least about 95% of silica modified with at least about 2.5% to about 10% by weight of calcium metasilicate.

Embodiment #36 is the method of embodiment #35, wherein the platinum is present in an amount of at least 1 weight percent.

Embodiment #37 is the process of embodiment #2, which is carried out at a temperature of about 250 ℃ to 300 ℃, wherein (a) the surface area of the modified siliceous support is at least about 100 g/m; (b) wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2; (c) the modified siliceous support comprises silica modified with at least about 2.5% to about 10% by weight calcium metasilicate at a purity of at least about 95%.

Embodiment #38 is the method of embodiment #37, wherein the platinum is present in an amount of at least 0.75 wt.%.

Embodiment #39 is the method of embodiment #38, wherein the catalyst occupies the reactor volume and is in the gas phase for at least about 1000hr^-1Is passed through the reactor volume.

Embodiment #40 is the method of embodiment #38, wherein the catalyst occupies the reactor volume and is in the gas phase at least about 2500hr^-1Is passed through the reactor volume.

Embodiment #41 is the method of embodiment #40, wherein the amounts and oxidation states of platinum and tin, as well as the ratio of platinum to tin, and the modified siliceous support are controlled such that: (i) converting at least 90% of the converted acetic acid to ethanol: (ii) less than 2% of the acetic acid is converted to other than ethanol, ethylCompounds other than aldehydes, ethyl acetate and ethylene and mixtures thereof; and (iii) when at a pressure of 2atm, a temperature of 275 ℃ and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 336 hours, the catalyst activity decreases by less than 10%.

Embodiment #42 is the method of embodiment #38, wherein the catalyst occupies the reactor volume and is in the gas phase for at least about 5000hr^-1Is passed through the reactor volume.

Embodiment #43 is the method of embodiment #42, wherein the amounts and oxidation states of platinum and tin, as well as the ratio of platinum to tin, and the modified siliceous support are controlled such that: (i) converting at least 90% of the converted acetic acid to ethanol; (ii) less than 2% of the acetic acid is converted to alkanes; (iii) when the pressure is 2atm, the temperature is 275 deg.C and the time is 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 168 hours, the catalyst activity decreases by less than 10%.

Embodiment #44 is the process of embodiment #43, which is carried out at a temperature of about 250 ℃ to 300 ℃, wherein (a) the modified siliceous support has a surface area of at least about 200m²(ii)/g; (b) the molar ratio of tin to platinum is from about 5: 4 to about 4: 5; (c) the modified siliceous support comprises silica modified with at least about 2.5% to about 10% by weight calcium silicate having a purity of at least about 95%.

Embodiment #45 is a process for producing ethanol by reducing acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a molar ratio of hydrogen to acetic acid of at least about 4: 1 in the vapor phase at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst comprising oxygenPlatinum and tin dispersed on a compound-based support, wherein the amount and oxidation state of platinum and tin, and the ratio of platinum to tin, and the oxide-based support are selected, configured and controlled such that: (i) converting at least 80% of the converted acetic acid to ethanol; (ii) less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, and mixtures thereof; and when the pressure is 2atm, the temperature is 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 500 hours, the catalyst activity decreases by less than 10%.

Embodiment #46 is the method of embodiment #45, wherein the hydrogenation catalyst consists essentially of platinum and tin dispersed on an oxide-based support and the oxide-based support is a modified oxide-based support comprising an effective amount of a support modifier selected from the group consisting of: (i) an alkaline earth metal oxide, (ii) an alkali metal oxide, (iii) an alkaline earth metal metasilicate, (iv) an alkali metal metasilicate, (v) zinc oxide, (vi) zinc metasilicate and (vii) a precursor of any of (i) - (vi), and any mixture of (i) - (vii).

Embodiment #47 is method #46 of embodiment, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #48 is the method of embodiment #47, wherein (a) platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #49 is the process of embodiment #47, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #50 is the method of embodiment #46, wherein the support modifier is selected from the group consisting of sodium, potassium, magnesium, calcium, and zinc metasilicates, as well as precursors thereof and mixtures of any of the foregoing.

Embodiment #51 is the method of embodiment #50, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #52 is the method of embodiment #51, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #53 is the method of embodiment #46, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #54 is the method of embodiment #53, wherein (a) the platinum is present in an amount from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #55 is the method of embodiment #54, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #56 is the method of embodiment #46, wherein the support modifier is selected from the group consisting of metasilicates of magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #57 is the method of embodiment #56, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #58 is the method of embodiment #57, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #59 is the method of embodiment #46, wherein the support modifier is selected from the group consisting of calcium metasilicate, a precursor of calcium metasilicate, and a mixture of calcium metasilicate and a precursor thereof.

Embodiment #60 is the method of embodiment #59, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #61 is the process of embodiment #60, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #62 is the method of embodiment #46, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #63 is the method of embodiment #62, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

Embodiment #64 is the method of embodiment #62, wherein the support has a surface area of at least about 100m²/g。

Embodiment #65 is the method of embodiment #64, wherein the molar ratio of tin to platinum group metal is from about 1: 2 to about 2: 1.

Embodiment #66 is the method of embodiment #64, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #67 is the method of embodiment #64, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #68 is the method of embodiment #46, wherein the support has a surface area of at least about 150m²/g。

Embodiment #69 is the method of embodiment #68, wherein (a) the platinum is present in an amount from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-5%.

Embodiment #70 is the method of embodiment #68, wherein the carrier comprises at least about 1% to about 10% by weight calcium silicate.

Embodiment #71 is the method of embodiment #68, wherein the molar ratio of tin to platinum is from about 1: 2 to about 2: 1.

Embodiment #72 is the method of embodiment #68, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #73 is the method of embodiment #68, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #74 is the method of embodiment #46, wherein the support has a surface area of at least about 200m²/g。

Embodiment #75 is method #74 of an embodiment, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #76 is the method of embodiment #74, wherein the molar ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #77 is the process of embodiment #74, wherein the molar ratio of tin to platinum is from about 9: 10 to about 10: 9.

Embodiment #78 is a process for producing ethanol by reducing acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid at a molar ratio of hydrogen to acetic acid of at least about 4: 1 in the vapor phase at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of platinum and tin dispersed on a modified stabilized siliceous support comprising silica modified with a stabilizer-modifier selected from the group consisting of: (i) an alkaline earth metal oxide, (ii) an alkali metal oxide, (iii) an alkaline earth metal metasilicate, (iv) an alkali metal metasilicate, (v) zinc oxide, (vi) zinc metasilicate and (vii) a precursor of any of (i) - (vi), and any mixture of (i) - (vii), wherein the amounts and oxidation states of platinum and tin, the ratio of platinum to tin, the relative proportions of stabilizer-modifier to silica in the modified stabilized siliceous support, and the purity of the silica in the modified stabilized siliceous support are controlled such that at least 80% of the converted acetic acid is converted to ethanol and less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, and mixtures thereof.

Embodiment #79 is the method of embodiment #78, wherein (a) the platinum is present in an amount from 0.5% to 5% by weight of the catalyst; and (b) tin is present in an amount of at least 0.5-10%.

Embodiment #80 is the method of embodiment #79, wherein the modified stabilized siliceous support has a surface area of at least about 100m²/g。

Embodiment #81 is the method of embodiment #80, wherein the molar ratio of tin to platinum group metal is from about 1: 2 to about 2: 1.

Embodiment #82 is the process of embodiment #80, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #83 is the method of embodiment #79, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #84 is the method of embodiment #78, wherein the modified stabilized siliceous support has a surface area of at least about 150m²/g。

Embodiment #85 is the method of embodiment #84, wherein (a) the platinum is present in an amount ranging from 0.5% to 5% by weight of the catalyst; (b) the tin is present in an amount of at least 0.5-5%.

Embodiment #86 is the method of embodiment #84, wherein the modified stabilized siliceous support comprises at least about 1% to about 10% by weight calcium silicate.

Embodiment #87 is the method of embodiment #84, wherein the molar ratio of tin to platinum is from about 1: 2 to about 2: 1.

Embodiment #88 is the method of embodiment #84, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #89 is the method of embodiment #84, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #90 is the method of embodiment #87, wherein the modified stabilized siliceous support has a surface area of at least about 200m²/g。

Embodiment #91 is the method of embodiment #90, wherein the molar ratio of tin to platinum is from about 9: 10 to about 10: 9.

Embodiment #92 is the method of embodiment #90, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #93 is the method of embodiment #90, wherein the molar ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #94 is the method of embodiment #90, wherein the modified stabilized siliceous support has a surface area of at least about 250m²/g。

Embodiment #95 is the process of embodiment #78, which is carried out at a temperature of about 250 ℃ to 300 ℃, wherein (a) the surface area of the modified stabilized siliceous support is at least about 250m²(ii)/g; (b) platinum is present in the hydrogenation catalyst in an amount of at least about 0.75 wt.%; (c) the molar ratio of tin to platinum is from about 5: 4 to about 4: 5; (d) modified stabilized siliceous carrier packageAt least about 2.5% to about 10% by weight calcium silicate.

Embodiment #96 is the method of embodiment #95, wherein the platinum is present in an amount of at least 1 weight percent.

Embodiment #97 is the process of embodiment #78, which is carried out at a temperature of about 250 ℃ to 300 ℃, wherein (a) the surface area of the modified stabilized siliceous support is at least about 100 g/m; (b) wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2; (c) the modified stabilized siliceous support comprises at least about 2.5% to about 10% by weight calcium silicate.

Embodiment #98 is the method of embodiment #97, wherein the platinum is present in an amount of at least 0.75 wt.%.

Embodiment #99 is the method of embodiment #98, wherein the catalyst occupies the reactor volume and is in the gas phase for at least about 1000hr^-1Is passed through the reactor volume.

Embodiment #100 is the process of embodiment #98, wherein the catalyst occupies the reactor volume and is in the gas phase for at least about 2500hr^-1Is passed through the reactor volume.

Embodiment #101 is the process of embodiment #100, wherein the amounts and oxidation states of platinum and tin, as well as the ratio of platinum to tin and the composition of the modified stabilized siliceous support are controlled such that at least 90% of the converted acetic acid is converted to ethanol and less than 2% of the acetic acid is converted to compounds other than compounds selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, and ethylene and mixtures thereof.

Embodiment #102 is the method of embodiment #98, wherein the catalyst occupies the reactor volume and is in the gas phase for at least about 5000hr^-1Is passed through the reactor volume.

Embodiment #103 is the method of embodiment #79, wherein the amounts and oxidation states of platinum and tin, as well as the ratio of platinum to tin and the composition of the modified stabilized siliceous support are controlled such that: at least 90% of the converted acetic acid is converted to ethanol and less than 2% of the acetic acid is converted to alkanes.

Embodiment #104 is the process of embodiment #79, which is carried out at a temperature of about 250 ℃ to 300 ℃, wherein (a) wherein the amount and oxidation state of platinum and tin, as well as the ratio of platinum to tin and the acidity of the modified stabilized siliceous support are controlled such that at least 90% of the converted acetic acid is converted to ethanol and less than 1% of the acetic acid is converted to alkanes; (b) the surface area of the modified stabilized siliceous support is at least about 200m²(ii)/g; (c) the molar ratio of tin to platinum is from about 5: 4 to about 4: 5; (d) the modified stabilized siliceous support comprises at least about 2.5% to about 10% by weight calcium silicate.

Embodiment #105 is a process for producing ethanol by reducing acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a molar ratio of hydrogen to acetic acid of at least about 4: 1 in the vapor phase at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of: a catalytic metal selected from the group consisting of Fe, Co, Cu, Ni, Ru, Rh, Pd, Ir, Pt, Sn, Re, Os, Ti, Zn, Cr, Mo and W, and mixtures thereof, in an amount of from about 0.1% to about 10% by weight; and an optional promoter dispersed on a suitable support, wherein the amount and oxidation of the catalytic metal is controlledThe composition of the carrier and optional promoter and the reaction conditions are such that: (i) converting at least 80% of the converted acetic acid to ethanol; (ii) less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, diethyl ether, and mixtures thereof; and when the pressure is 2atm, the temperature is 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 500 hours, the catalyst activity decreases by less than 10%.

Embodiment #106 is the method of embodiment #105, wherein the support is an oxide-based support modified with a modifier selected from the group consisting of: oxides and metasilicates of sodium, potassium, magnesium, calcium, scandium, yttrium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #107 is the method of embodiment #105, wherein the support is a carbon support and the catalytic metal comprises platinum and tin.

Embodiment #108 is the method of embodiment #107, wherein the carbon support is modified with a reducible metal oxide.

Embodiment #109 is a process for producing ethanol by hydrogenating acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of a metal component dispersed on an oxide-based support, the hydrogenation catalyst having a composition of:

Pt_vPd_wRe_xSn_yAl_zCa_pSi_qO_r，

wherein v and y are from 3: 2 to 2: 3; w and x are 1: 3 to 1: 5, wherein the relative positions of p and Z and the aluminum atoms and calcium atoms present are controlled such that Bronsted acid sites present on the surface thereof are balanced by calcium silicate; p and q are selected such that p: q is from 1: 20 to 1: 200, wherein r is selected to satisfy valence requirements, and v and w are selected such that:

embodiment #110 is the process of embodiment #109, wherein the hydrogenation catalyst has at least about 100m²A surface area per gram, and wherein z and p are controlled such that p ≧ z.

Embodiment #111 is the method of embodiment #110, wherein p is selected to ensure that the support surface is substantially free of bronsted acid sites, taking into account any minor impurities present.

Embodiment #112 is a process for hydrogenating acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of: a catalytic metal selected from the group consisting of Fe, Co, Cu, Ni, Ru, Rh, Pd, Ir, Pt, Sn, Re, Os, Ti, Zn, Cr, Mo and W, and mixtures thereof, in an amount of from about 0.1% to about 10% by weight; and an optional promoter dispersed on a suitable support, wherein the amount and oxidation state of the catalytic metal is controlled, the composition of the support and optional promoter, and the reaction conditions are such that less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, diethyl ether, and mixtures thereof; and when the pressure is 2atm, the temperature is 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 500 hours, the catalyst activity decreases less than 10%, with the other conditions being: (i) wherein the support is an oxide-based support modified with a modifier selected from the group consisting of: oxides and metasilicates of sodium, potassium, magnesium, calcium, scandium, yttrium, and zinc, and precursors thereof, and mixtures of any of the foregoing; (ii) (ii) the support is a carbon support and the catalytic metal comprises platinum and tin or (iii) the support is a carbon support modified with a reducible metal oxide.

Embodiment #113 is a process for hydrogenating alkanoic acids comprising passing a gaseous stream comprising hydrogen and alkanoic acid in a molar ratio of hydrogen to alkanoic acid of at least about 2: 1 in the vapor phase at a temperature from about 125 ℃ to 350 ℃ over a hydrogenation catalyst comprising: a platinum group metal selected from platinum, palladium and mixtures thereof on a siliceous support selected from silica, calcium metasilicate and calcium metasilicate promoted silica; and a promoter selected from the group consisting of tin, rhenium, and mixtures thereof, wherein the silicon-containing carrier is optionally promoted with a promoter selected from the group consisting of: (a) a promoter selected from the group consisting of alkali metals, alkaline earth elements and zinc in an amount of 1-5% by weight of the catalyst; (b) selected from WO in an amount of 1-50% by weight of the catalyst₃、MoO₃、Fe₂O₃And Cr₂O₃A redox type accelerator of (a); and (c) TiO in an amount of 1-50% by weight of the catalyst₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃The acidic modifier of (1).

Embodiment #114 is the method of embodiment #113, wherein the alkanoic acid is acetic acid, and wherein (a) at least one of platinum and palladium is present in an amount ranging from 0.25% to 5% by weight of the catalyst; (b) the total amount of platinum and palladium present is at least 0.5% by weight of the catalyst; and (c) the total amount of rhenium and tin present is at least 0.5 to 10 weight percent.

Embodiment #115 is the method of embodiment #114, wherein the silicon containing support has a surface area of at least about 150m²/g。

Embodiment #116 is the method of embodiment #115, wherein (a) the amounts and oxidation states of the platinum group metal, rhenium, and tin promoters are controlled, and (b) the molar ratio of the platinum group metal to the total moles of rhenium and tin present is controlled; and (c) the number of bronsted acid sites on the silicon containing support is such that at least 80% of the converted acetic acid is converted to a compound selected from the group consisting of ethanol and ethyl acetate and at the same time less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene and mixtures thereof.

Embodiment #117 is the method of embodiment #115, wherein (a) at least one of platinum and palladium is present in an amount ranging from 0.5% to 5% by weight of the catalyst; (b) the total amount of platinum and palladium present is at least 0.75% to 5% by weight of the catalyst; and (c) the total amount of tin and rhenium present is at least 1.0% by weight of the catalyst.

Embodiment #118 is the process of embodiment #117 wherein (a) the amounts and oxidation states of (i) the platinum group metal, (ii) the rhenium and tin promoters, and (iii) the ratio of the platinum group metal to the rhenium and tin promoters are controlled; and (iv) the siliceous support has an acidity such that at least 80% of the converted acetic acid is converted to ethanol and less than 4% of the acetic acid is converted to compounds other than compounds selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, and mixtures thereof.

Embodiment #119 is the process of embodiment #118, wherein the combined weight of rhenium and tin present is from about 1 to 10 percent by weight of the catalyst.

Embodiment #120 is the method of embodiment #119, wherein the molar ratio of the platinum group metal to the total moles of rhenium and tin is from about 1: 2 to about 2: 1.

Embodiment #121 is a process for hydrogenating acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of a metal component dispersed on an oxide-based support, the hydrogenation catalyst having a composition of:

Pt_vPd_wRe_xSn_yCa_pSi_qO_r，

wherein the ratio of v to y is 3: 2 to 2: 3; w: x is from 1: 3 to 1: 5, p and q are selected such that p: q is from 1: 20 to 1: 200, wherein r is selected to satisfy valence requirements, and v and w are selected such that:

embodiment #122 is the method of embodiment #121, wherein the process conditions and values of v, w, x, y, p, q, and r are selected such that at least 90% of the converted acetic acid is converted to a compound selected from the group consisting of ethanol and ethyl acetate, and at the same time less than 4% of the acetic acid is converted to alkanes.

Embodiment #123 is method #122 of embodiment, wherein the process conditions and values of v, w, x, y, p, q, and r are selected such that at least 90% of the converted acetic acid is converted to ethanol and less than 2% of the acetic acid is converted to alkanes.

Embodiment #124 is the method of embodiment #122, wherein p is selected to ensure that the support surface is substantially basic, taking into account any minor impurities present.

Embodiment #125 is a process for hydrogenating acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of a metal component dispersed on an oxide-based support, the hydrogenation catalyst having a composition of:

Pt_vPd_wRe_xSn_yAl_zCa_pSi_qO_r，

wherein v and y are from 3: 2 to 2: 3; w and x are 1: 3 to 1: 5, wherein p and z and the relative positions of the aluminum atoms and the calcium atoms present are controlled such that Bronsted acid sites present on the surface thereof are balanced by calcium silicate; p and q are selected such that p: q is from 1: 20 to 1: 200, wherein r is selected to satisfy valence requirements, and v and w are selected such that:

embodiment #126 is the method of embodiment #125, wherein the hydrogenation catalyst has at least about 100m²A surface area per gram, and wherein z and p are controlled such that p ≧ z.

Embodiment #127 is the method of embodiment #125, wherein p is selected to ensure that the support surface is substantially free of bronsted acid sites, taking into account any minor impurities present.

Embodiment #128 is a process for hydrogenating alkanoic acids which comprises hydrogenating alkanoic acid in the vapor phase at a molar ratio of hydrogen to alkanoic acid of at least about 5: 1 at a temperature of about 125 deg.C to 350 deg.C for at least about 1000hr^-1Passing a gaseous stream comprising hydrogen and alkanoic acid over a hydrogenation catalyst at a pressure of at least 2atm, the hydrogenation catalyst comprising: (a) a platinum group metal selected from platinum, palladium and mixtures thereof on a siliceous support selected from silica, calcium metasilicate and calcium metasilicate promoted silica; and (b) a metal promoter selected from the group consisting of tin, rhenium, and mixtures thereof, (c) a silicon-containing support optionally promoted with a second promoter selected from the group consisting of: (i) a donor promoter selected from alkali metals, alkaline earth elements and zinc in an amount of 1 to 5% by weight of the catalyst; (ii) selected from WO in an amount of 1-50% by weight of the catalyst₃、MoO₃、Fe₂O₃And Cr₂O₃A redox type accelerator of (a); (iii) selected from TiO in an amount of 1-50% by weight of the catalyst₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃An acidic modifier of (1); and (iv) combinations of i, ii and iii.

Embodiment #129 is the process of embodiment #128, wherein the alkanoic acid is acetic acid, and wherein (a) platinum, if present, is present in an amount from 0.5% to 5% by weight of the catalyst; (b) palladium (if present) is present in an amount of 0.5% to 5% by weight of the catalyst; and (c) a metal promoter is present in an amount of at least 0.5-10%.

Embodiment #130 is the method of embodiment #129, wherein the silicon containing support has a surface area of at least about 150m²/g。

Embodiment #131 is the method of embodiment #130, wherein (a) the platinum is present in an amount of 1% to 5% by weight of the catalyst; (b) palladium (if present) is present in an amount of 0.25% to 5% by weight of the catalyst; and (c) the total amount of platinum and palladium present is at least 1.25% by weight of the catalyst.

Embodiment #132 is the method of embodiment #131, wherein the tin is present in an amount of 1 to 3% by weight of the catalyst.

Embodiment #133 is method #132 of an embodiment wherein the molar ratio of tin to platinum group metal is from about 1: 2 to about 2: 1.

Embodiment #134 is the process of embodiment #132, wherein the molar ratio of tin to platinum is from about 5: 4 to about 4: 5.

Embodiment #135 is the method of embodiment #132, wherein the siliceous support is substantially free of bronsted acid sites not neutralized by calcium metasilicate and has a surface area of at least about 200m²/g。

Embodiment #136 is method #132 of an embodiment, wherein the weight ratio of tin to platinum group metal is from about 2: 3 to about 3: 2.

Embodiment #137 is the method of embodiment #128, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

Embodiment #138 is a process for hydrogenating acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of: a catalytic metal selected from the group consisting of Fe, Co, Cu, Ni, Ru, Rh, Pd, Ir, Pt, Sn, Os, Ti, Zn, Cr, Mo and W, and mixtures thereof, in an amount of from about 0.1% to about 10% by weight; and an optional promoter dispersed on a suitable support, wherein the amount and oxidation state of the catalytic metal is controlled, the composition of the support and optional promoter and the reaction conditions are such that less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, diethyl ether and mixtures thereof; and when the pressure is 2atm, the temperature is 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 500 hours, the catalyst activity decreases by less than 10%.

Embodiment #139 is the method of embodiment #138, wherein the carrier is selected from the group consisting of: a molecular sieve support; a modified siliceous support modified with a modifying agent selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, scandium, yttrium, and zinc, and precursors thereof and mixtures of any of the foregoing, and a carbon support.

Embodiment #140 is the method of embodiment #139, wherein the catalytic metal comprises platinum and tin, and the selectivity to diethyl ether is greater than 80%.

Embodiment #141 is the method of embodiment #107, wherein the support is a zeolite support and the selectivity to diethyl ether is greater than 90%.

Embodiment #142 is a process for producing ethanol and ethyl acetate by reducing acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a molar ratio of hydrogen to acetic acid of at least about 4: 1 in the vapor phase at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst comprising: (a) a platinum group metal selected from platinum and mixtures of platinum and palladium on a siliceous support selected from silica and silica promoted with up to about 7.5 calcium metasilicate, the platinum group metal being present in an amount of at least about 2.0% and the platinum being present in an amount of at least about 1.5%; and (b) a metal promoter selected from rhenium and tin in an amount of from about 1% to 2% by weight of the catalyst, the molar ratio of platinum to metal promoter being from about 3: 1 to 1: 2; (c) a siliceous support optionally promoted with a second promoter selected from (i) a donor promoter selected from the group consisting of alkali metals, alkaline earth elements and zinc in an amount of 1 to 5% by weight of the catalyst; (ii) selected from WO in an amount of 1-50% by weight of the catalyst₃、MoO₃、Fe₂O₃And Cr₂O₃A redox type accelerator of (a); (iii) selected from TiO in an amount of 1-50% by weight of the catalyst₂、ZrO₂、Nb₂O₅、Ta₂O₅And Al₂O₃An acidic modifier of (1); and (iv) combinations of i, ii and iii.

Embodiment #143 is the method of embodiment #142, wherein the molar ratio of metal promoter to platinum group metal is from about 2: 3 to about 3: 2.

Embodiment #144 is the process of embodiment #142, wherein the molar ratio of metal promoter to platinum group metal is from about 5: 4 to about 4: 5.

Embodiment #145 is the method of embodiment #142, wherein the silicon containing support has a surface area of at least about 200m²(iv) g, and the amount of calcium metasilicate is sufficient to render the surface of the siliceous support substantially free of Bronsted acidity.

Embodiment #146 is the process of embodiment #145, wherein the molar ratio of metal promoter to platinum group metal is from about 2: 3 to about 3: 2.

Embodiment #147 is the method of embodiment #146, wherein the silicon containing support has a surface area of at least about 200m²(iv)/g, and the number of moles of bronsted acid sites present on the surface thereof is not greater than the number of moles of bronsted acid sites present on the surface of Saint-Gobain NorPro SS61138 silica.

Embodiment #148 is the method of embodiment #142, wherein the silicon containing support has a surface area of at least about 250m²(iv)/g, and the number of moles of bronsted acid sites present on the surface thereof is not more than half of the number of moles of bronsted acid sites present on the surface of Saint-Gobain NorPro HSA SS61138 silica.

Embodiment #149 is the process of embodiment #142, which is carried out at a temperature of about 250 ℃ to about 300 ℃, wherein (a) the hydrogenation catalyst comprises palladium on a siliceous support selected from the group consisting of silica and silica promoted with up to about 7.5 calcium metasilicate, the palladium being present in an amount of at least about 1.5%; and (b) the metal promoter is rhenium in an amount from about 1% to 10% by weight of the catalyst, the molar ratio of rhenium to palladium being from about 3: 1 to 5: 1.

Embodiment #150 is the acetic acid reduction process of embodiment #142, wherein the hydrogenation catalyst consists essentially of platinum present in an amount of at least about 1.0% on a siliceous support consisting essentially of silica promoted with about 3 up to about 7.5% calcium silicate, the tin promoter being present in an amount of about 1% to about 5% by weight of the catalyst, the molar ratio of platinum to tin being about 9: 10 to 10: 9.

Embodiment #151 is the method of acetic acid reduction of embodiment #142, wherein the platinum group metal is present in an amount of at least about 2.0%, the platinum is present in an amount of at least about 1.5%, the tin promoter is in an amount of about 1% to 5% by weight of the catalyst, and the molar ratio of platinum to tin is from about 9: 10 to 10: 9.

Embodiment #152 is the process of embodiment #151, carried out at a temperature of about 250 ℃ to 300 ℃, wherein the hydrogenation catalyst comprises: at a surface area of at least 200m²2.5-3.5 wt.% platinum, 2-5 wt.% tin dispersed on/g of high surface area silica promoted with 4-7.5% calcium metasilicate.

Embodiment #153 is a process for producing a stream comprising ethanol and at least about 40% ethyl acetate by reducing acetic acid, the process comprising passing a gaseous stream comprising hydrogen and acetic acid in a gas phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of a metal component dispersed on an oxide-based support, the hydrogenation catalyst having a composition of:

Pt_vPd_wRe_xSn_yAl_zTi_nCa_pSi_qO_r，，

wherein the ratio of v to y is from 3: 2 to 2: 3; w and x are in a ratio of 1: 3 to 1: 5, wherein p, z and p, q and n are selected such that:

wherein r is selected to satisfy valence requirements, and v and w are selected such that:

embodiment #154 is the process of embodiment #153, wherein the hydrogenation catalyst has at least about 100m²Surface area in g.

Embodiment #155 is a process for hydrogenating acetic acid comprising passing a gaseous stream comprising hydrogen and acetic acid in a vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of: a catalytic metal selected from the group consisting of Fe, Co, Cu, Ni, Ru, Rh, Pd, Ir, Pt, Sn, Os, Ti, Zn, Cr, Mo and W, and mixtures thereof, in an amount of from about 0.1% to about 10% by weight; and on a suitable carrierA dispersed optional promoter, wherein the amount and oxidation state of the catalytic metal is controlled, the composition of the support and optional promoter and the reaction conditions are such that: i) converting greater than 50% of the converted acetic acid to ethyl acetate; (ii) less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, diethyl ether, and mixtures thereof; and when the pressure is 2atm, the temperature is 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 500 hours, the catalyst activity decreases by less than 10%.

Embodiment #156 is a particulate catalyst for the hydrogenation of an alkanoic acid to the corresponding alkanol, the particulate catalyst comprising: (a) a platinum group metal selected from platinum, palladium and mixtures thereof on a siliceous support selected from silica and silica promoted with about 3.0 up to about 7.5 calcium metasilicate, the siliceous support having a surface area of at least about 150m²(ii)/g; and (b) a tin promoter in an amount of about 1% to about 3% by weight of the catalyst, the molar ratio of platinum to tin being about 4: 3 to about 3: 4; (c) the composition and structure of the silicon-containing carrier is selected such that the surface thereof is substantially free of bronsted acid sites that are not counteracted by the calcium metasilicate.

Embodiment #157 is the hydrogenation catalyst of embodiment #156, wherein the total weight of platinum group metals present is 2 to 4%, the amount of platinum present is at least 2%, the weight ratio of platinum to tin is 4: 5 to 5: 4, and the amount of calcium silicate present is 3 to 7.5%.

Embodiment #158 is a particulate hydrogenation catalyst consisting essentially of: a silicon-containing carrier having dispersed thereon a platinum group metal selected from platinum, palladium and mixtures thereof and a promoter selected from tin, cobalt and rhenium, the silicon-containing carrier having at least about 175m²Per gram surface area and selected from the group consisting of silica, calcium metasilicate, and calcium metasilicate promoted silica (having metasilicate located on a surface thereof)Calcium) the surface of the silicon-containing support is substantially free of bronsted acid sites due to alumina not being equilibrated by calcium.

Embodiment #159 is the hydrogenation catalyst of embodiment #158, wherein the total weight of platinum group metals present is from 0.5% to 2%, the amount of palladium present is at least 0.5%, the promoter is rhenium, the weight ratio of rhenium to palladium is from 10: 1 to 2: 1, and the amount of calcium metasilicate is from 3 to 90%.

Embodiment #160 is the hydrogenation catalyst of embodiment #159, wherein the total weight of platinum group metals present is from 0.5 to 2%, the amount of platinum present is at least 0.5%, the promoter is cobalt, the weight ratio of cobalt to platinum is from 20: 1 to 3: 1, and the amount of calcium silicate is from 3 to 90%.

Embodiment #161 is the hydrogenation catalyst of embodiment #158, wherein the platinum group metals are present in a total weight amount of 0.5 to 2%, the palladium is present in an amount of at least 0.5%, the promoter is cobalt, the weight ratio of cobalt to palladium is 20: 1 to 3: 1, and the calcium silicate is present in an amount of 3 to 90%.

Embodiment #162 is a hydrogenation catalyst comprising: at a surface area of at least 200m²2.5-3.5 wt.% platinum and 3-5 wt.% tin dispersed per gram of high surface area fumed silica, said high surface area silica promoted with 4-6% calcium metasilicate, the molar ratio of platinum to tin being 4: 5 to 5: 4.

Embodiment #163 is a hydrogenation catalyst comprising: 0.5 to 2.5 wt.% palladium, 2 wt.% to 7 wt.% rhenium, and a rhenium to palladium weight ratio of at least 1.5: 1.0, wherein both rhenium and palladium are dispersed on a silicon-containing support comprising at least 80% calcium metasilicate.

Embodiment #164 is a particulate catalyst for the hydrogenation of an alkanoic acid to the corresponding alkanol, the particulate catalyst comprising: (a) a platinum group metal selected from platinum, palladium and mixtures thereof on a siliceous support selected from modified stabilized siliceous supports, the siliceous support being modified and stabilized with a stabilizer-modifier selected from the group consisting of: (i) an alkaline earth metal oxide, (ii) an alkali metal oxide, (iii) an alkaline earth metal metasilicate, (iv) an alkali metal metasilicate, (v) zinc oxide, (vi) zinc metasilicate and (vii) a precursor of any of (i) - (vi), and any mixture of (i) - (vii), the modified stabilized siliceous support having a surface area of at least about 150m²(ii)/g; and (b) a tin promoter in an amount of from about 1% to about 3% by weight of the catalyst, the molar ratio of platinum to tin being from about 4: 3 to about 3: 4.

Embodiment #165 is the hydrogenation catalyst of embodiment #164, wherein the total weight of platinum group metals present is from 2 to 4%, the amount of platinum present is at least 2%, the weight ratio of platinum to tin is from 4: 5 to 5: 4, and the amount of stabilizer-modifier present is from 3 to 7.5%.

Embodiment #166 is the hydrogenation catalyst of embodiment #165, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #167 is the hydrogenation catalyst of embodiment #165, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #168 is the hydrogenation catalyst of embodiment #165, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #169 is the hydrogenation catalyst of embodiment #165, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #170 is the hydrogenation catalyst of embodiment #165, wherein the support modifier is selected from the group consisting of calcium metasilicate, a precursor of calcium metasilicate, and a mixture of calcium metasilicate and a precursor thereof.

Embodiment #171 is the hydrogenation catalyst of embodiment #164, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #172 is the hydrogenation catalyst of embodiment #164, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #173 is the hydrogenation catalyst of embodiment #164, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #174 is the hydrogenation catalyst of embodiment #164, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof and mixtures of any of the foregoing.

Embodiment #175 is the hydrogenation catalyst of embodiment #164, wherein the support modifier is selected from the group consisting of calcium metasilicate, a precursor of calcium metasilicate, and a mixture of calcium metasilicate and a precursor thereof.

Embodiment #176 is a particulate hydrogenation catalyst consisting essentially of: a modified stabilized siliceous support having dispersed thereon a platinum group metal selected from the group consisting of platinum, palladium and mixtures thereof and a promoter selected from the group consisting of tin, cobalt and rhenium, the siliceous support comprising a silica having a purity of at least 95% and at least about 175m²(ii) silica modified and stabilized with a stabilizer-modifier selected from the group consisting of: (i) an alkaline earth metal oxide, (ii) an alkali metal oxide, (iii) an alkaline earth metal metasilicate, (iv) an alkali metal metasilicate, (v) zinc oxide, (vi) zinc metasilicate and (vii) a precursor of any of (i) - (vi), and any mixture of (i) - (vii), the surface of the silicon-containing support being substantially free of bronsted acid sites due to the alumina not being equilibrated by the stabilizer-modifier.

Embodiment #177 is the hydrogenation catalyst of embodiment #176, wherein the total weight of platinum group metals present is from 0.5% to 2%, the amount of palladium present is at least 0.5%, the promoter is rhenium, the weight ratio of rhenium to palladium is from 10: 1 to 2: 1, and the amount of the support-modifier is from 3 to 90%.

Embodiment #178 is the hydrogenation catalyst of embodiment #177 wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof and mixtures of any of the foregoing.

Embodiment #179 is the hydrogenation catalyst of embodiment #177, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #180 is the hydrogenation catalyst of embodiment #177, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #181 is the hydrogenation catalyst of embodiment #177, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #182 is the hydrogenation catalyst of embodiment #177, wherein the support modifier is selected from the group consisting of calcium metasilicate, a precursor of calcium metasilicate, and a mixture of calcium metasilicate and a precursor thereof.

Embodiment #183 is the hydrogenation catalyst of embodiment #176 wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof and mixtures of any of the foregoing.

Embodiment #184 is the hydrogenation catalyst of embodiment #176 wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #185 is the hydrogenation catalyst of embodiment #176 wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof and mixtures of any of the foregoing.

Embodiment #186 is the hydrogenation catalyst of embodiment #176 wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof and mixtures of any of the foregoing.

Embodiment #187 is the hydrogenation catalyst of embodiment #176 wherein the support modifier is selected from the group consisting of calcium metasilicate, a precursor of calcium metasilicate, and a mixture of calcium metasilicate and a precursor thereof.

Embodiment #188 is the hydrogenation catalyst of embodiment #176, wherein the total weight of platinum group metals present is from 0.5 to 2%, the amount of platinum present is at least 0.5%, the promoter is cobalt, the weight ratio of cobalt to platinum is from 20: 1 to 3: 1, and the amount of support modifier is from 3 to 90%.

Embodiment #189 is the hydrogenation catalyst of embodiment #188, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof and mixtures of any of the foregoing.

Embodiment #190 is the hydrogenation catalyst of embodiment #188, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #191 is the hydrogenation catalyst of embodiment #188, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #192 is the hydrogenation catalyst of embodiment #188, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #193 is the hydrogenation catalyst of embodiment #188, wherein the support modifier is selected from the group consisting of calcium metasilicate, a precursor of calcium metasilicate, and a mixture of calcium metasilicate and a precursor thereof.

Embodiment #194 is the hydrogenation catalyst of embodiment #176, wherein the total weight of platinum group metals present is from 0.5 to 2%, the amount of palladium present is at least 0.5%, the promoter is cobalt, the weight ratio of cobalt to palladium is from 20: 1 to 3: 1, and the amount of support modifier is from 3 to 90%.

Embodiment #195 is the hydrogenation catalyst of embodiment #194, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #196 is the hydrogenation catalyst of embodiment #194, wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

Embodiment #197 is the hydrogenation catalyst of embodiment #194, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #198 is the hydrogenation catalyst of embodiment #194, wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium, and zinc, and precursors thereof, and mixtures of any of the foregoing.

Embodiment #199 is the hydrogenation catalyst of embodiment #194, wherein the support modifier is selected from the group consisting of calcium metasilicate, a precursor of calcium metasilicate, and a mixture of calcium metasilicate and a precursor thereof.

Embodiment #200 is a hydrogenation catalyst comprising: at a surface area of at least 200m²2.5-3.5 wt.% platinum and 3-5 wt.% tin dispersed per gram of high surface area fumed silica, said high surface area silica promoted with 4-6% calcium metasilicate, the molar ratio of platinum to tin being 4: 5 to 5: 4.

Embodiment #201 is a hydrogenation catalyst comprising: 0.5 to 2.5 wt.% palladium, 2 wt.% to 7 wt.% rhenium, and a rhenium to palladium weight ratio of at least 1.5: 1.0, wherein the rhenium and palladium are both dispersed on a silicon-containing support comprising at least 80% calcium metasilicate.

Embodiment #202 is a hydrogenation catalyst incorporating a catalytic metal selected from the group consisting of Fe, Co, Ni, Ru, Rh, Pd, Ir, Pt, Os, Ti, Zn, Cr, Mo and W in an amount of from about 0.1 wt% to about 10 wt% on a stabilized modified oxide-based support incorporating alkaline earth metals, alkali metals, oxides and metasilicates of zinc, scandium, yttrium, precursor forms of these oxides and metasilicates, and mixtures thereof, a basic non-volatile stabilizer-modifier on the surface thereof in an amount sufficient to counteract the presence of acid sites thereon; imparting resistance to shape change at temperatures encountered with acetic acid hydrogenation (shape change due primarily to sintering, grain growth, grain boundary migration, defect and dislocation migration, plastic deformation, and/or other temperature-induced microstructural changes, among other things); or both.

Embodiment #203 is the hydrogenation catalyst of embodiment #202, wherein the amount and location of the basic modifier-stabilizer is sufficient to reduce the number of acid sites present per square meter on the surface of the oxide-based support to below the number of acid sites found per square meter on the surface of the fumed silica having a purity of at least about 99.7 weight percent.

Embodiment #204 is the hydrogenation catalyst of embodiment #202, wherein the amount and location of the basic modifier-stabilizer is sufficient to reduce the number of acid sites present per square meter on the surface of the oxide-based support to below the number of acid sites found per square meter on the surface of Saint-Gobain norproahsa SS61138 having a purity of at least about 99.7 wt.%.

Embodiment #205 is the hydrogenation catalyst of embodiment #202, wherein the amount and location of the basic modifier-stabilizer is sufficient to reduce the number of acid sites present per square meter on the surface of the oxide-based support to less than half of the number of acid sites found per square meter on the surface of the fumed silica having a purity of at least about 99.7 weight percent.

Embodiment #206 is the hydrogenation catalyst of embodiment #202, wherein the amount and location of the basic modifier-stabilizer is sufficient to reduce the number of acid sites present per square meter on the surface of the oxide-based support to less than half of the number of acid sites found per square meter on a Saint-Gobain norproahsa SS61138 surface having a purity of at least about 99.7 wt.%.

Embodiment #207 is the hydrogenation catalyst of embodiment #202, wherein the amount and location of the basic modifier-stabilizer is sufficient to reduce the number of acid sites present per square meter on the surface of the oxide-based support to less than 25% of the number of acid sites found per square meter on the surface of the fumed silica having a purity of at least about 99.7 weight percent.

Embodiment #208 is the hydrogenation catalyst of embodiment #202, wherein the amount and location of the basic modifier-stabilizer is sufficient to reduce the number of acid sites present per square meter on the surface of the oxide-based support to less than 25% of the number of acid sites found per square meter on a Saint-Gobain norproahsa SS61138 surface having a purity of at least about 99.7 wt%.

Embodiment #209 is the hydrogenation catalyst of embodiment #202, wherein the amount and location of the basic modifier-stabilizer is sufficient to reduce the number of acid sites present per square meter on the surface of the oxide-based support to less than 10% of the number of acid sites found per square meter on the surface of the fumed silica having a purity of at least about 99.7 weight percent.

Embodiment #210 is the hydrogenation catalyst of embodiment #202, wherein the amount and location of the basic modifier-stabilizer is sufficient to reduce the number of acid sites present per square meter on the surface of the oxide-based support to less than 10% of the number of acid sites found per square meter on a Saint-Gobain norproahsa SS61138 surface having a purity of at least about 99.7 wt%.

In the foregoing description of the various embodiments, the embodiments that refer to another embodiment may be combined with other embodiments as appropriate, as will be recognized by those skilled in the art.

Claims

1.A process for producing ethanol by reducing acetic acid, the process comprising passing a gaseous stream comprising hydrogen and acetic acid in a vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst comprising platinum and tin dispersed on a silicon-containing support, wherein the amount and oxidation state of platinum and tin, and the ratio of platinum to tin, and the silicon-containing support are selected, configured and controlled such that: (i) converting at least 80% of the converted acetic acid to ethanol; (ii) less than 4% of the acetic acid is converted to a compound other than acetic acid selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene andcompounds other than compounds of mixtures thereof; and when the pressure is 2atm, the temperature is 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 168 hours, the catalyst activity decreases by less than 10%.

2. The process of claim 1 wherein the hydrogenation catalyst consists essentially of platinum and tin dispersed on a silicon-containing support and the silicon-containing support is a modified silicon-containing support comprising an effective amount of a support modifier selected from the group consisting of: (i) alkaline earth metal oxides, (ii) alkali metal oxides, (iii) alkaline earth metal metasilicates, (iv) alkali metal metasilicates, (v) zinc oxide, (vi) zinc metasilicate and (vii) precursors of (i) - (vi), and mixtures of (i) - (vii).

3. The process of claim 2 wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof and mixtures of the foregoing.

4. The method of claim 2, wherein:

a. platinum is present in an amount of 0.5% to 5% by weight of the catalyst; and

b. the tin is present in an amount of at least 0.5-10%.

5. The process of claim 3 wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

6. The process of claim 2 wherein the support modifier is selected from the group consisting of sodium, potassium, magnesium, calcium and zinc metasilicates and their precursors and mixtures of the foregoing.

7. The method of claim 5, wherein:

b. the tin is present in an amount of at least 0.5-10%.

8. The process of claim 6 wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

9. The process of claim 2 wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium and zinc, and precursors thereof and mixtures of the foregoing.

10. The method of claim 9, wherein:

b. the tin is present in an amount of at least 0.5-10%.

11. The process of claim 10, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

12. The process of claim 2 wherein the support modifier is selected from the group consisting of metasilicates of magnesium, calcium and zinc, and precursors thereof and mixtures of the foregoing.

13. The method of claim 12, wherein:

b. the tin is present in an amount of at least 0.5-10%.

14. The process of claim 12, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

15. The process of claim 2, wherein the support modifier is selected from the group consisting of calcium metasilicate, precursors of calcium metasilicate, and mixtures of calcium metasilicate and its precursors.

16. The method of claim 15, wherein:

b. the tin is present in an amount of at least 0.5-10%.

17. The process of claim 16, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

18. The method of claim 2, wherein:

b. the tin is present in an amount of at least 0.5-10%.

19. The process of claim 16, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

20. The method of claim 18, wherein the surface area of the support is at least about 100m²/g。

21. The method of claim 20, wherein the molar ratio of tin to platinum group metal is from about 1: 2 to about 2: 1.

22. The method of claim 20, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

23. The method of claim 20, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

24. The process of claim 2 wherein the support has a surface area of at least about 150m²/g。

25. The method of claim 24, wherein:

b. the tin is present in an amount of at least 0.5-5%.

26. The method of claim 24, wherein the carrier comprises at least about 1% to about 10% by weight calcium silicate.

27. The method of claim 24, wherein the molar ratio of tin to platinum is from about 1: 2 to about 2: 1.

28. The method of claim 24, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

29. The method of claim 24, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

30. The process of claim 2 wherein the support has a surface area of at least about 200m²/g。

31. The method of claim 30, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

32. The method of claim 30, wherein the molar ratio of tin to platinum is from about 5: 4 to about 4: 5.

33. The method of claim 30, wherein the molar ratio of tin to platinum is from about 9: 10 to about 10: 9.

34. The method of claim 33, wherein the modified siliceous support has a surface area of at least about 250m²/g。

35. The process of claim 2, carried out at a temperature of about 250 ℃ to 300 ℃, wherein:

a. the modified siliceous support has a surface area of at least about 250m²/g；

b. Platinum is present in the hydrogenation catalyst in an amount of at least about 0.75 wt.%;

c. the molar ratio of tin to platinum is from about 5: 4 to about 4: 5; and

d. the modified siliceous support comprises silica modified with at least about 2.5 wt.% to about 10 wt.% calcium metasilicate at a purity of at least about 95%.

36. The method of claim 35, wherein the platinum is present in an amount of at least 1 wt.%.

37. The process of claim 2, carried out at a temperature of about 250 ℃ to 300 ℃, wherein:

a. the modified siliceous support has a surface area of at least about 100 g/m;

b. wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2; and

c. the modified siliceous support comprises silica modified with at least about 2.5 wt.% to about 10 wt.% calcium metasilicate at a purity of at least about 95%.

38. The method of claim 37, wherein the platinum is present in an amount of at least 0.75 weight percent.

39. The method of claim 38, wherein the catalyst occupies the reactor volume and is in the gas phase for at least about 1000hr^-1Is passed through the reactor volume.

40. The method of claim 38, wherein the catalyst occupies the reactor volume and is present in the gas phase for at least about 2500hr^-1Is passed through the reactor volume.

41. The method of claim 40 wherein the amount and oxidation state of platinum and tin, and the ratio of platinum to tin and the modified siliceous support are controlled such that: (i) converting at least 90% of the converted acetic acid to ethanol; (ii) is less than2% of the acetic acid is converted to compounds other than those selected from the group consisting of ethanol, acetaldehyde, ethyl acetate and ethylene and mixtures thereof; and (iii) when at a pressure of 2atm, a temperature of 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 336 hours, the catalyst activity decreases by less than 10%.

42. The method of claim 38, wherein the catalyst occupies the reactor volume and is in the gas phase for at least about 5000hr^-1Is passed through the reactor volume.

43. The method of claim 42 wherein the amount and oxidation state of platinum and tin, and the ratio of platinum to tin and the modified siliceous support are controlled such that: (i) converting at least 90% of the converted acetic acid to ethanol; (ii) less than 2% of the acetic acid is converted to alkanes; (iii) when the pressure is 2atm, the temperature is 275 deg.C and the time is 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 168 hours, the catalyst activity decreases by less than 10%.

44. The process of claim 43, carried out at a temperature of about 250 ℃ to 300 ℃, wherein:

a. the modified siliceous support has a surface area of at least about 200m²/g；

b. The molar ratio of tin to platinum is from about 5: 4 to about 4: 5;

c. the modified siliceous support comprises silica having a purity of at least about 95% and the modifying agent comprises at least about 2.5% by weight to about 10% by weight calcium silicate.

45. A process for producing ethanol by reducing acetic acid, the process comprising passing a gaseous stream comprising hydrogen and acetic acid in a molar ratio of hydrogen to acetic acid of at least about 4: 1 in the vapor phase at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst comprising a catalyst that is oxidized to produce ethanolPlatinum and tin dispersed on a support of the species, wherein the amount and oxidation state of platinum and tin, and the ratio of platinum to tin, and the support of the oxide species are selected, configured and controlled such that: (i) converting at least 80% of the converted acetic acid to ethanol; (ii) less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, and mixtures thereof; and when the pressure is 2atm, the temperature is 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 500 hours, the catalyst activity decreases by less than 10%.

46. The process of claim 45, wherein the hydrogenation catalyst consists essentially of platinum and tin dispersed on an oxide-based support and the oxide-based support is a modified oxide-based support comprising an effective amount of a support modifier selected from the group consisting of: (i) alkaline earth metal oxides, (ii) alkali metal oxides, (iii) alkaline earth metal metasilicates, (iv) alkali metal metasilicates, (v) zinc oxide, (vi) zinc metasilicate and (vii) precursors of (i) - (vi), and mixtures of (i) - (vii).

47. The process of claim 46 wherein the support modifier is selected from the group consisting of oxides and metasilicates of sodium, potassium, magnesium, calcium, and zinc, and precursors thereof and mixtures of the foregoing.

48. The method of claim 47, wherein:

b. the tin is present in an amount of at least 0.5-10%.

49. The method of claim 47, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

50. The method of claim 46, wherein the support modifier is selected from the group consisting of sodium, potassium, magnesium, calcium, and zinc metasilicates, and precursors thereof and mixtures of the foregoing.

51. The method of claim 50, wherein:

c. platinum is present in an amount of 0.5% to 5% by weight of the catalyst; and

d. the tin is present in an amount of at least 0.5-10%.

52. The method of claim 51, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

53. The process of claim 46 wherein the support modifier is selected from the group consisting of oxides and metasilicates of magnesium, calcium and zinc, and precursors thereof and mixtures of the foregoing.

54. The method of claim 53, wherein:

b. the tin is present in an amount of at least 0.5-10%.

55. The method of claim 54, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

56. The process of claim 46 wherein the support modifier is selected from the group consisting of metasilicates of magnesium, calcium and zinc, and precursors thereof and mixtures of the foregoing.

57. The method of claim 56, wherein:

b. the tin is present in an amount of at least 0.5-10%.

58. The method of claim 57, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

59. The method of claim 46, wherein the support modifier is selected from the group consisting of calcium metasilicate, a precursor of calcium metasilicate, and a mixture of calcium metasilicate and a precursor thereof.

60. The method of claim 59, wherein:

b. the tin is present in an amount of at least 0.5-10%.

61. The method of claim 60, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

62. The method of claim 46, wherein:

e. platinum is present in an amount of 0.5% to 5% by weight of the catalyst; and

f. the tin is present in an amount of at least 0.5-10%.

63. The method of claim 62, wherein the molar ratio of platinum to tin is from 4: 5 to 5: 4.

64. The method of claim 62, wherein the support has a surface area of at least about 100m²/g。

65. The method of claim 64, wherein the molar ratio of tin to platinum group metal is from about 1: 2 to about 2: 1.

66. The method of claim 64, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

67. The method of claim 64, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

68. The process of claim 46 wherein the support has a surface area of at least about 150m²/g。

69. The method of claim 68, wherein:

b. the tin is present in an amount of at least 0.5-5%.

70. The method of claim 68, wherein the carrier comprises at least about 1% to about 10% by weight calcium silicate.

71. The method of claim 68, wherein the molar ratio of tin to platinum is from about 1: 2 to about 2: 1.

72. The method of claim 68, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

73. The method of claim 68, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

74. The process of claim 46 wherein the support has a surface area of at least about 200m²/g。

75. The method of claim 74, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

76. The method of claim 74, wherein the molar ratio of tin to platinum is from about 5: 4 to about 4: 5.

77. The method of claim 74, wherein the molar ratio of tin to platinum is from about 9: 10 to about 10: 9.

78. A process for producing ethanol by reducing acetic acid, the process comprising passing a gaseous stream comprising hydrogen and acetic acid at a molar ratio of hydrogen to acetic acid of at least about 4: 1 in the vapor phase at a temperature of about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of platinum and tin dispersed on a modified stabilized siliceous support comprising silica modified with a stabilizer-modifier selected from the group consisting of: (i) an alkaline earth metal oxide, (ii) an alkali metal oxide, (iii) an alkaline earth metal metasilicate, (iv) an alkali metal metasilicate, (v) zinc oxide, (vi) zinc metasilicate and (vii) precursors of (i) - (vi), and mixtures of (i) - (vii), wherein the amounts and oxidation states of platinum and tin, the ratio of platinum to tin, the relative proportions of stabilizer-modifier and silica in the modified stabilized siliceous support, and the purity of the silica in the modified stabilized siliceous support are controlled such that at least 80% of the converted acetic acid is converted to ethanol and less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, and mixtures thereof.

79. The method of claim 78, wherein:

b. the tin is present in an amount of at least 0.5-10%.

80. The method of claim 79, wherein the surface area of the modified stabilized siliceous support is at least about 100m²/g。

81. The method of claim 80, wherein the molar ratio of tin to platinum group metal is from about 1: 2 to about 2: 1.

82. The method of claim 80, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

83. The method of claim 79, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

84. The method of claim 78, wherein the modificationHas a surface area of at least about 150m²/g。

85. The method of claim 84, wherein:

b. the tin is present in an amount of at least 0.5-5%.

86. The method of claim 84, wherein the modified stabilized siliceous support comprises at least about 1% to about 10% by weight calcium silicate.

87. The method of claim 84, wherein the molar ratio of tin to platinum is from about 1: 2 to about 2: 1.

88. The method of claim 84, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

89. The method of claim 84, wherein the weight ratio of tin to platinum is from about 5: 4 to about 4: 5.

90. The method of claim 87, wherein the modified stabilized siliceous support has a surface area of at least about 200m²/g。

91. The method of claim 90, wherein the molar ratio of tin to platinum is from about 9: 10 to about 10: 9.

92. The method of claim 90, wherein the molar ratio of tin to platinum is from about 2: 3 to about 3: 2.

93. The method of claim 90, wherein the molar ratio of tin to platinum is from about 5: 4 to about 4: 5.

94. The method of claim 90, wherein saidThe surface area of the modified stabilized siliceous support is at least about 250m²/g。

95. The process of claim 78, which is carried out at a temperature of about 250 ℃ to 300 ℃, wherein:

a. the surface area of the modified stabilized siliceous support is at least about 250m²/g；

c. the molar ratio of tin to platinum is from about 5: 4 to about 4: 5; and

d. the modified stabilized siliceous support comprises at least about 2.5% to about 10% by weight calcium silicate.

96. The method of claim 95, wherein the platinum is present in an amount of at least 1 weight percent.

97. The process of claim 78, which is carried out at a temperature of about 250 ℃ to 300 ℃, wherein:

a. the surface area of the modified stabilized siliceous support is at least about 100 g/m;

c. the modified stabilized siliceous support comprises at least about 2.5% to about 10% by weight calcium silicate.

98. The method of claim 97, wherein the platinum is present in an amount of at least 0.75 weight percent.

99. The method of claim 98, wherein the catalyst occupies the reactor volume and is in the gas phase for at least about 1000hr^-1Is passed through the reactor volume.

100. The process of claim 98, wherein the catalyst occupies the reactor volume and is in the gas phaseAt least about 2500hr^-1Is passed through the reactor volume.

101. The method of claim 100 wherein the amount and oxidation state of platinum and tin, as well as the ratio of platinum to tin and the composition of the modified stabilized siliceous support are controlled such that: at least 90% of the converted acetic acid is converted to ethanol and less than 2% of the acetic acid is converted to compounds other than compounds selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, and ethylene, and mixtures thereof.

102. The method of claim 98, wherein the catalyst occupies the reactor volume and is in the gas phase for at least about 5000hr^-1Is passed through the reactor volume.

103. The method of claim 79 wherein the amount and oxidation state of platinum and tin, as well as the ratio of platinum to tin and the composition of the modified stabilized siliceous support are controlled such that: at least 90% of the converted acetic acid is converted to ethanol and less than 2% of the acetic acid is converted to alkanes.

104. The process of claim 79, carried out at a temperature of about 250 ℃ to 300 ℃, wherein:

a. wherein the amount and oxidation state of platinum and tin, as well as the ratio of platinum to tin and the acidity of the modified stabilized siliceous support are controlled such that: converting at least 90% of the converted acetic acid to ethanol, less than 1% of the acetic acid to alkanes;

b. the surface area of the modified stabilized siliceous support is at least about 200m²/g；

c. The molar ratio of tin to platinum is from about 5: 4 to about 4: 5;

105. By adding acetic acidA process for the reductive production of ethanol, the process comprising passing a gaseous stream comprising hydrogen and acetic acid in a vapor phase at a hydrogen to acetic acid molar ratio of at least about 4: 1 at a temperature of from about 225 ℃ to 300 ℃ over a hydrogenation catalyst consisting essentially of: a catalytic metal selected from the group consisting of Fe, Co, Cu, Ni, Ru, Rh, Pd, Ir, Pt, Sn, Re, Os, Ti, Zn, Cr, Mo and W, and mixtures thereof, in an amount of from about 0.1% to about 10% by weight; and an optional promoter dispersed on a suitable support, wherein the amount and oxidation state of the catalytic metal is controlled, the composition of the support and optional promoter and the reaction conditions are such that: (i) converting at least 80% of the converted acetic acid to ethanol; (ii) less than 4% of the acetic acid is converted to a compound other than a compound selected from the group consisting of ethanol, acetaldehyde, ethyl acetate, ethylene, diethyl ether, and mixtures thereof; and when the pressure is 2atm, the temperature is 275 deg.C and 2500hr^-1Is exposed to a vaporous mixture of acetic acid and hydrogen at a molar ratio of 10: 1 for a period of 500 hours, the catalyst activity decreases by less than 10%.

106. The method of claim 105, wherein the support is an oxide-based support modified with a modifier selected from the group consisting of: oxides and metasilicates of sodium, potassium, magnesium, calcium, scandium, yttrium, and zinc, as well as precursors thereof, and mixtures of any of the foregoing.

107. The process of claim 105, wherein the support is a carbon support and the catalytic metal comprises platinum and tin.

108. The method of claim 107, wherein the carbon support is modified with a reducible metal oxide.