MXPA99007915A - Improved catalysts for the hydrogenation of maleic acid to 1,4-butanediol - Google Patents

Abstract

Se describe un catalizador mejorado para la hidrogenación delácido maleico, anhídrido maleico u otro precursor hidrogenable que hidrogenan catalíticamente a 1,4-butanodiol y tetrahidrofurano. Este catalizador de hidrogenación comprende paladio, plata, renio y al menos uno de hierro, aluminio, cobalto y mezclas de los mismos, todos en un soporte de carbono.

Description

IMPROVED CATALYSTS FOR THE HYDROGENATION OF MALEIC ACID TO 1, 4-BTJTANODIOL Field of Invention This invention relates to an improved catalyst for the hydrogenation of maleic acid, maleic anhydride or other hydrogenatable precursor for 1-butanediol and tetrahydrofuran. The catalyst comprises palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof, all on a carbon support. The use of. This catalyst in processes for the hydrogenation of maleic acid, anhydride or other hydrogenatable precursor for 1, -bu t-anodiol and etrahydrofuran is characterized by a high overall activity for reaction products and by high yields of 1, -butenediol with minimum formations of by-products of range-but irol act ona.

Background of the Invention It is well known that tetrahydrofuran, gamma -bu thyrolactone and 1, -bunediol are obtained Ref: 031079 for the catalytic hydrogenation of maleic anhydride and related compounds. Tetrahydrofuran is a useful solvent for natural and synthetic resins and is a valuable intermediary in the manufacture of a number of chemicals and plastics. The gamma-butyrolactone is an intermediate for the synthesis of compounds of butyric acid, polyvinylpyrrolidone and methionine. The gamma-butyrolactone * is a useful solvent for acrylate and styrene polymers and also a useful ingredient for paint removers and textile assistants. 1,4-Butanediol (aka 1,4-butylene glycol) is useful as a solvent, a humectant, an intermediate for plasticizers and pharmaceuticals, a crosslinking agent for polyurethane elastomers, a precursor in the manufacture of tetrahydrofuran, and It is useful for making terephthalate plastics.

Of particular interest in the present invention are the hydrogenation catalysts comprising palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof, all on a carbon support, which are useful for the hydrogenation of the anhydride maleic, maleic acid and compounds related to tetrahydrofuran, gamma-butyrolactone and 1,4-but anodiol.

British Patent No. 1,534,232 teaches the hydrogenation of carboxylic acids, lactones or anhydrides using a hydrogenation catalyst consisting of palladium and rhenium on a carbon support. U.S. Patent Nos. 4,550,185 and 4,609,636 teach a process for making tetrahydrofuran and 1,4-bunediol by hydrogenated maleic acid, maleic anhydride or other hydrogenatable precursor in the presence of a catalyst comprising palladium and rhenium on a carbon support wherein the palladium and rhenium occur in the form of crystallites having an average size of palladium crystallites of about 10 to 25 nm and an average size of rhenium crystallites of at least 2.5 nm. The "preparation of this catalyst is characterized by the destitution of the palladium species in the carbon support followed by the removal and reduction of the rhenium species in the palladium by impregnating the carbon support.

U.S. Patent No. 4,985,572 teaches a process for the catalytic hydrogenation of a carboxylic acid or an anhydride thereof to the corresponding alcohol and / or carboxylic acid ester using a catalyst comprising rhenium, palladium and at least one other metal capable of mixing with palladium, all in a carbon holder. The preferred metal capable of mixing with palladium is silver but gold, copper, nickel, rhodium, tin, cobalt, aluminum, manganese, gallium, iron, chromium, and platinum are also taught. The preparation of this catalyst is characterized by the simultaneous deposition of palladium and silver on the carbon support followed by a high temperature (600 ° C) heat treatment. The rhenium is then deposited in the palladium / me mixed impregnated with carbon support. The resulting catalyst is then reduced.

WO 92/02298 describes a hydrogenation catalyst comprising palladium and rhenium and one or more metals selected from the group consisting of rhodium, cobalt, platinum, ruthenium, iron, thulium, cerium, yttrium, neodymium, aluminum, praseodymium, holmium, hafnium, manganese, vanadium, chrome, gold, terbium, lutetium, nickel, scandium and niobium, in a support.

Generally, in the hydrogenation of maleic acid, maleic anhydride or other hydrogenatable precursor the catalysts discussed above are prone to produce more tetrahydrofuran and gamma-butyrolactone than 1,4-butanediol. An object of this invention is a process and a catalyst that can maximize the production of 1,4-but anodiol and minimize the production of gamma-butyiolactone.

BRIEF DESCRIPTION OF THE INVENTION The present invention is a catalyst comprising palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof, all on a carbon support and the use of this catalyst in a process for the production of 1, -butanediol comprising catalytically hydrogenating a hydrogenatable precursor in contact with a gas containing hydrogen.

Another embodiment of the present invention is a method for making such a catalyst for the production of 1-butanediol comprising: (i) oxidizing a carbon support by contacting the carbon support with an oxidizing agent; (ii) impregnating in one or more impregnation steps comprising contacting a carbon support with a source of palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof; (iii) drying the impregnated carbon support to remove the solvent after each impregnation step; and (iv) heating the impregnated carbon support from room temperature to a temperature between about 100 ° C and about 350 ° C "under reduced conditions.

Detailed description of the invention A catalyst comprising palladium, rhenium, silver and at least one of iron, aluminum, cobalt 1 and mixtures thereof, all on a carbon support, are employed in the hydrogenation of a hydrogenatable precursor to provide high yields of 1, 4 -butanediol and small yields of tetrahydrofuran with minimal formation of gamma-butyrolactone.

The Reagents In the process of the present invention, at least one hydrogenatable precursor reacts with a hydrogen containing gas in the presence of the catalyst. As used herein, a "hydrogenatable precursor" is any carboxylic acid or anhydride thereof, carboxylic acid ester, lactone or mixture thereof when producing hydrogenated 1,4-butanediol. Representative hydrogenatable precursors include maleic acid, maleic anhydride, fumaric acid, succinic anhydride, succinic acid, succinate ester such as dimethyl succinate, maleate esters such as dimethyl maleate, gamma-butyrolactone or mixtures thereof. Preferred hydrogenatable precursors are maleic acid, maleic anhydride, succinic acid, succinic anhydride or mixtures thereof.

The most preferred hydrogenatable precursor is maleic acid which is typically obtained by reaction of n-butane or benzene in an oxygen-containing gas in the presence of a catalyst to oxidize the n-butane or benzene to the maleic anhydride in the vapor phase, and then Collect maleic anhydride by quenching water to produce maleic acid in an aqueous solution. The oxidation of n-butane or benzene is typically operated at a temperature of about 300 ° C to 600 ° C and a pressure of about 0.5 to 20 atmospheres (50 to 2000 kPa).

Typically, hydrogen (H2) containing gas is commercially pure hydrogen with undiluted gases. However, the hydrogen containing gas for addition to the hydrogen (H2) may also contain nitrogen (N2), any gaseous hydrocarbon (for example methane), as well as gaseous carbon oxides, (for example carbon monoxide, carbon dioxide).

The Catalyst.

The catalyst employed in the present invention comprises palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof, all supported on carbon. The carbons for use in this invention have a BET surface area of at least 200 m2 / g, and preferably are in the range of 500-1500 m2 / g.

The catalyst composition comprises from about 0.1 to about 20 weight percent palladium, preferably from about 2 to about 8 weight percent palladium, more preferably from about 2 to about 4 weight percent palladium; about 0.1 to about 20 weight percent silver, preferably about 1 to about 8 weight percent silver, more preferably about 2 to about 4 weight percent silver; about 0.1 to about 20 weight percent rhenium, preferably about 1 to about 10 weight percent rhenium, more preferably about 5 to about 9 weight percent rhenium; and about 0.01 to about 10 weight percent of at least one of iron, aluminum, cobalt and mixtures thereof, preferably about 0.1 to about 5 weight percent of at least one of iron, aluminum, cobalt and mixtures thereof, more preferably from about 0.2 to about 0.6 weight percent of at least one of iron, aluminum, cobalt and mixtures thereof. The ratio of palladium to silver is between 10 to 1 and 1 to 10. The catalyst composition can also be further modified through the incorporation of a metal or metals selected from Groups IA, HA or VIII.

The catalyst of this invention can conveniently be prepared by oxidizing the carbon support (however this treatment step is optional) followed by the impregnation of the carbon support, either in simple or multiple impregnation steps, with a solution or solutions containing at least a palladium, silver, rhenium or a compound of iron, aluminum, or cobalt.

Preferably, the carbon support is first oxidized by contact with the carbon support, prior to removal of the metals, with an oxidizing agent. Catalysts prepared in this manner show a dramatic improvement in activity and selectivity over catalysts prepared with a non-oxidizing carbon support. A number of oxidizing agents such as nitric acid, hydrogen peroxide, sodium hypochlorite, ammonium persulfate, perchloric acid, and oxygen, can be effective in this process. The liquid phase oxidizing agents are preferred. Nitric acid at elevated temperatures is found to be especially effective for this procedure. The gas phase oxidizing agents include any gas containing oxygen, for example, air. The gaseous oxidizing agents are contacted with the carbon support at temperatures of about 200 ° C or higher and at pressures around atmospheric or higher. Optionally one or more metals, such as iron, nickel, palladium, rhenium, silver, gold, copper, rhodium, tin, cobalt, manganese, gallium, and platinum, can be mixed with the oxidizing agent and subsequently deposited on the carbon support during the pre-treatment of the oxidizing agent of the carbon support.

As a first state, the catalysts of this invention are prepared by impregnation of the carbon support, either in simple or multiple impregnation steps, with a solution or solutions containing at least one palladium, silver, rhenium, iron, aluminum or cobalt compound . As used herein, impregnation of the carbon support means causing the carbon support to be filled, impregnated, permeated, saturated or coated. The impregnation solution may optionally contain complex agents to help solubilize one or more of the metal compounds. The impregnation solution can also optionally be combined with the oxidizing agent before or in situ by contacting the carbon support. The catalyst is dried after each impregnation step to remove any carrier solvent. The drying temperatures are between about 80 ° C and about 150 ° C.

The palladium compound solutions, composed of silver, rhenium compound, iron compound, aluminum compound, cobalt compound or mixtures thereof may be applied to the carbon by immersion or suspension of the support material in the solution or by spraying the solution into the carbon. The solution containing the palladium compound is typically an aqueous solution containing an amount of palladium compound to produce a catalytic product with the required amount of palladium. The palladium compound may be palladium nitrate or a palladium compound such as a chloride, carbonate, carboxylate, acetate, acetyl acetone, or amine. The solution containing the silver compound is typically an aqueous containing an amount of silver compound to produce a catalytic product with the required amount of silver. The palladium and silver compounds can be thermally decomposed and reduced to metals. The solution containing the rhenium compound is typically an aqueous containing an amount of rhenium compound to produce a catalytic product with the required amount of rhenium. The rhenium compound is typically perrhenic acid, ammonium perrhenate or an alkali metal perrhenate. The solution containing the iron compound is typically an aqueous containing an amount of iron compound to produce a catalytic product with the required amount of iron. The iron compound is typically ferric nitrate, but other suitable iron-containing compounds include, but are not limited to, ferrous acetate, ferric acetate, ferrous chloride, ferrous fumarate, and ferric fumarate. The solution containing the aluminum compound is typically an aqueous solution containing an amount of aluminum compound to produce a catalyst product with the required amount of aluminum. The aluminum compound is typically aluminum nitrate, but other suitable aluminum-containing compounds include, but are not limited to, aluminum acetate and aluminum chloride. The solution containing the cobalt compound is typically an aqueous containing an amount of cobalt compound to produce a catalytic product with the required amount of cobalt. The cobalt compound is typically cobalt nitxate, but other suitable cobalt-containing compounds include, but are not limited to, cobalt acetate, cobalt chloride, cobalt maleate, and cobalt fumarate.

The impregnation solution (s) may optionally contain metal complexing agents to help solubilize one or more of the metal compounds. The addition of acetonitrile to the impregnating solution mixes the compounds Pd, Ag, and Re to be added in a simple step. Nitric acid or other oxidizing agent can be added to the impregnating solution.

After impregnation with palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof and then drying the impregnated carbon support, the catalyst is activated by heating the impregnated carbon support under reduced temperature conditions. environment (this is typical four temperature) up to a temperature between about 120 ° C and 350 ° C, preferably between about 150 ° C and about 300 ° C. The hydrogen, or a mixture of hydrogen and nitrogen, in contact with the catalyst, can be conveniently used for the reduction of the catalyst. The reduction of the impregnated carbon support is only after the carbon support has been impregnated with palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof. In the case of multiple and multiple dried impregnation steps, the reduction of the catalyst is made after the final drying.

The palladium in the catalyst of the present invention is present in the crystallite form having an average crystallite size of less than 100 angstroms (10 nm). More specifically, when fresh reduced palladium / silver / rhenium samples on a carbon support as used herein are analyzed by X-ray diffraction (XRD) and Random Transmission Electron Microscopy (STEM), the palladium containing particles (that is, palladium particles, palladium and silver particles, or palladium and rhenium particles) in the catalyst, are finely dispersed and have an average crystallite size of less than about 50 angstroms (5 nm). As used herein, the "particle size distribution" and "average particle size" are as defined in "Structure of Metals Catalyst" by JR Anderson, pages 358-359, Academic Press (1975), which is incorporated herein for reference.

Finally, the preparation of the catalyst described here does not employ large amounts of excess water that can be removed during the drying step or the high temperature treatment step (ie, around 600 ° C) is employed as taught in 1. -US Patent 4,985, 572.

During the completion of the catalytic preparation described herein, iron, aluminum or cobalt are present in the catalyst. However, during the hydrogenation of the maleic acid and depending on the conditions in the hydrogenation reactor, some iron, aluminum or cobalt can be leached from the catalyst. In the case of PdAgReFe in carbon catalyst, the iron leaching of the catalyst is observed to be occasionally extensive, so that it does not detect iron in the catalyst after several weeks of current.

The process The method for carrying out the process comprises reacting a hydrogenatable precursor with a gas containing hydrogen in the presence of the hydrogenation catalyst, and coating and purifying the reaction products by distillation.

The liquid phase hydrogenation of this invention can be run using conventional apparatus and techniques in a stirred tank reactor or in a flexible bed reactor. Single or multiple stage reactor can be used. The amount of catalyst required can be very varied and will depend on the number of factors such as reactor size and design, contact time and the like.

The gas containing hydrogen is fed continuously, generally with hydrogen in a considerable stoichiometric excess for the other reagents. The unreacted hydrogen can be returned to the reactor as a recycled stream. The precursor solution, for example, maleic acid solution, is continuously fed at concentrations in the range from diluted solutions to levels close to maximum solubility, typically about 30 to about 50 weight percent.

Preferably, the hydrogenation step runs at a temperature of about 50 ° C to 350 ° C, and a hydrogen pressure of about 20-400 atmospheres with hydrogen for hydrogenable precursor (H2 / P) ratio of between 5 to 1 and 1000 to 1 and contact times of 0.1 minute to 20 hours. For a maximum production of 1,4-butanediol, the reaction temperature is between about 50 ° C and 250 ° C and more preferably between about 80 ° C and 200 ° C.

The reaction products, 1, 4 -bunediol, tet ahydrofuran, gamma-butyrolactone or mixtures thereof, are advantageously separated by fractional distillation. The by-products that are formed in small amounts or feed without reaction, such as for example, succinic anhydride or succinic acid, are optionally returned to the hydrogenation state. The gamma-butyrolactone can also be recycled to the hydrogenation reactor.

Using the products of this invention, more specifically using the hydrogenation catalyst described herein, the maleic acid is converted virtually quantitatively into a simple reaction. The 1/4-butanediol and tetrahydrofuran yields are about 80 mole percent or more, typically about 90 mole percent or more, with a major yield portion being 1, -butanediol. The reaction of the by-products may include n-butanol, n-butyric acid, n-propanol, propionic acid, methane, propane, n-butane, carbon monoxide, and carbon dioxide. However, the formation of unusable byproducts is slight.

Preferred Modalities.

In order to illustrate the present invention, the following examples are provided.

Comparative Example A: Preparation of PdAgRe in carbon. 45 g of concentrated nitric acid (70% by weight) was diluted to 50 cc with deionized water. This solution was used to impregnate 74.6 g of ECSC 1.5 mm extruded carbon ACL40. During the impregnation the flask was cooled occasionally. The mixture was allowed to stand for 80 minutes, and then dried at 130 ° C for 3 hours. This procedure was distributed with a rest time of 35 minutes and a drying time of 16 hours. . 1 g of a palladium nitrate solution (8.5% by weight of Pd), 11.95 g of perrhenic acid solution (53.3% by weight of Re) and 7.9 g of concentrate (70% by weight of nitric acid) were diluted up to 50 ce with deionized water. The ACL40 was then impregnated gradually with the Pd + Re solution. The flask was cooled occasionally during the impregnation. The mixture was allowed to stand for 2 hours, and then dried at 130 ° C for 2 hours. 4. 7 g of silver nitrate and 7.9 g of concentrated nitric acid was diluted to 50 cc with deionized water. The Pd / Re / ACL40 was then gradually impregnated with the silver nitrate solution with occasional cooling of the flask. The mixture was allowed to stand for 3.5 hours, and then dried at 130 ° C for 64 hours. The resulting catalyst was 3.3% by weight Pd / 3.3% by weight Ag / 7.1% by weight Re.

Example 1: Preparation of PdAgReFe in carbon 45 g of concentrated nitric acid (70% by weight) and 1 g of ferric nitrate (Fe (N03) 3 '9H20) were diluted to 50 cc with deionized water. This solution was used to impregnate 74.6 g of ECSC 1.5 mm extruded carbon ACL40. During the impregnation, the flask was cooled occasionally, the mixture allowed to stand for 65 minutes, and then dried at 130 ° C for 2 hours. This procedure was repeated with 65 minutes of resting time and about 2.4 hours of drying time. . 1 of palladium nitrate solution (8.5% by weight of Pd), 11.95 g of perrhenic acid solution (53.3% by weight Re), 7.9 g of concentrated nitric acid (70% by weight), was diluted to 50 ce with deionized water. The ACL40 was gradually impregnated with the Pd / Re solution. The flask was cooled occasionally during the impregnation. The mixture was allowed to stand for 2.5 hours, and then dried at 130 ° C for 2.25 hours. 4. 7 g of silver nitrate and 7.9 g of concentrated nitric acid are diluted to 50 cc with deionized water. The Pd / Re / ACL40 is then impregnated gradually with the silver nitrate solution with occasional cooling in the flask. The mixture was allowed to stand for 80 minutes, and then dried at 130 ° C for 69 hours. The resulting catalyst was 3.3% by weight Pd 3.3% by weight Ag / 7.1% by weight Re / 0.3% by weight Fe.

E xemplo 2: Hydrogenation of Aqueous Maleic Acid and Catalyst Test.

The catalyst of Comparative Example A and the Example 1 were each tested in two reactors Hasteloy C276 connected in series using a Hasteloy C276 heat pipe. The reactors had an internal diameter of 0.516", and each was adapted with an axis of 1/8" Hasteloy C276 thermal. / Each catalyst was mixed with 50/70 quartz cutting mesh (0.625 g quartz per gram of catalyst) before charging to the reactor. 20 cc (12.15 g) of the catalyst were placed in the first reactor, and 40 cc (24.3 g) in the second reactor. Before the test, the catalyst was reduced to atmospheric pressure in a hydrogen flow (400 sccm) with the following temperature elevations: Ambient Temperature up to 30 ° C for 5 hours 30 ° C up to 100 ° C for 2 hours 100 ° C up to 230 ° C for 11 hours maintaining 230 ° C for 5 hours.

The reactors were operated with recycled hydrogen. A small portion of the hydrogen was vented to prevent the accumulation of non-condensable gases. The concentration of maleic acid in the liquid feed was 35.5% by weight. The process conditions for the catalyst tested were as the following process conditions: Pressure: 2500 psig H2 / Maleic Acid Feeding Ratio • H2 Tap for Recycling Ratio: 0.083 • First Reactor: Average Temperature in place: 100 ° C LHSV; 1.6 hours "" 1 • Second Reactor: Average Temperature in place: 153- 162 ° C LHSV: 0.8 hours "1.

Table 1 summarizes the results of the test on the PdAgRe / C and PdAgReFe / C catalysts. The selective products were calculated on a molar basis C.

Table 1 - Catalyst Performance Data Catalyst Hours in Temp. % BDO% THF% GBL% BuOH% SAC (C) sel. sel. sel. sel. sel. Current PdAgReFe / C 185 153 89.5 5.6 0.6 4.0 0.05 (E j us 1) PdAgRe / C 185 162 86.3 8.8 0.9 3.8 0.08 (Comparative Example) "Table 1 illustrates" that the performance of BDO is significantly greater for PdAgReFe / C. Table 1 also illustrates that the iron-containing catalyst (Example 1) is more active than the non-iron-containing species (Comparative Example). This is evidenced by better global conversions at the lowest reaction temperature.

Example 3: Preparation of PdAgReM in carbon, where M is Fe, Al, or Co. a) Preparation of the Precursor PdRe / Norit RXl .5 Extra. 584 g of carbon extruded Norit RXl .5 Extra (purchased from Norit Americas Inc. located in Atlanta, Georgia) was impregnated with 719 g of concentrated nitric acid (70% by weight). The material was allowed to stand for 90 minutes, and then dried in an oven at 130 ° C overnight. 218. 1 g of a palladium nitrate solution (8.5 wt% of Pd in 10 wt% of HN03), 114 g of perrhenic acid ^ 56.36 wt% of Re), 234.6 g of concentrated nitric acid, and 151 g of deionized water, mixed together. The carbon was impregnated with 96% of the Pd / Re solution, and the mixture was allowed to settle for 2 hours. After drying overnight at 130 ° C, 671.7 g of the material was obtained, with a Pd content of 2.6% by weight, and a Re content of 9.2% by weight. The moisture content (low weight% at 150 ° C) was 3.4% by weight. The material was slit into eight portions of ~ 84 g. b) Preparation of PdAgReM / Nori t RXl .5 Extra Three catalysts were prepared as described below, with M = Fe, Al or Co. The Table below summarizes the materials used for the different catalyst preparations: Table 2 The preparation of M = Fe is as follows: 2.5 g of silver nitrate, 6.9 g of concentrated nitric acid, and 2 g of Fe (N03) 3 '9H20, was added to 38 g of deionized water, and the mixture was stirred until the solids are dissolved. Then 63.4 g (140 c e) of PdRe / Norit (Slot Lot 1) was impregnated with the Ag / Fe solution, and the mixture was allowed to settle for about 2.5 hours. The material was then placed in an oven at 130 ° C, and dried for 4.5 hours. The other catalysts (M = A1 or Co) were prepared in a similar manner.

Example 4: Hydrogenation of Aqueous Maleic Acid PdAgReM in Carbon Catalyst, where M is Fe, Al, or Co.

The test catalyst was carried out using two Hasteloy C276 reactors connected in series using a Hasteloy C276 heat pipe. The reactors had an internal diameter of 0.516", and each was adapted with one with an axis of 1/8" Hasteloy C276 thermal.

The catalyst was mixed with 50/70 quartz cutting mesh (0.625 quarts per gram of catalyst) before charging to the reactor. 20 ce (12.15 g) of the catalyst were placed in the first reactor, and 40 c (24.3 g) in the second reactor. Before the test, the catalyst was reduced to atmospheric pressure in a hydrogen flow (400 sccm) with the following temperature elevations: Ambient Temperature up to 30 ° C in 5 hours 30-100 ° C in 2 hours 100-230 ° C in 11 hours @ 230 ° C in 5 hours.

The reactors were operated with recirculated hydrogen. A small portion of the hydrogen was vented to prevent the accumulation of non-condensable gases. The concentration of maleic acid in the aqueous liquid feed was 35.3% by weight. The process conditions for the test catalyst were as follows: • Pressure: 2500 psig • H2 / (MAC + FAC) Feed Ratio: 88 • H2 Recycling Ratio: 0.083 • First Reactor: Average Temperature in place 110 ° C LHSV; 1.6 hours "1 • Second Reactor: Average Temperature in place: 153- 162 ° C LHSV: 0.8 hours" 1.

Table 3 summarizes the results of the test for the catalyst PdAgReM / Norit RXl .5 Extra.

Table 3 Catalyst Performance Data TOS = Time in Current (hours) Place T = Temperature of the Reactor in Place (° C) Mass Bal = Balance of Mass BDO sel =% of Selectivity for 1, -bu tanodiol THF sel =% Selectivity for Tetrahydrofuran GBL sel =% Selectivity for Gamma-butyrolactone BuOH sel =% Selectivity for Butanol PrOH sel =% Selectivity for Propanol SAC sel =% Selectivity for Succinic Acid.

It will be understood that the object of the invention is not limited by the examples given herein. These are provided merely to demonstrate the operability, and the selection of catalysts, sources of metals, carbon supports, concentrations, contact times, filled with solids, raw materials, reaction conditions, and products, if any, can be determined from the description of the total specification provided, without departing from the spirit of the invention disclosed and described herein, the scope of the invention includes modifications and variations that "fall within the scope of the api indications rei.

It is noted that in relation to this date, the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description "of the invention.

Having described the invention as above, the content of the following is claimed as property.

Claims (25)

Claims

1. A catalyst, characterized in that it consists essentially of palladium, silver, rhenium and at least one of aluminum, cobalt and mixtures thereof on a carbon support.

2. The catalyst of claim 1, characterized in that it comprises between about 0.1 to about 20% by weight of palladium, between about 0.1 to about 20% by weight of silver, between about 0.1 to about 20% by weight of rhenium, and between about 0.1 to about 5% by weight of at least one of aluminum, cobalt and mixtures thereof.

3. The catalyst of claim 2, characterized in that it comprises about 2 to 4% by weight of palladium, about 2 up to 4% by weight of silver, about 5 to 9% by weight of rhenium, and about 0.2 to 0.6% by weight of at least one of aluminum, cobalt and mixtures thereof.

4. A process for the production of 1/4-butanediol, characterized in that it comprises catalytically hydrogenating a hydrogenatable precursor in contact with a gas containing hydrogen and a hydrogenation catalyst comprising palladium, silver, rhenium and at least one of aluminum, cobalt and mixtures of them, on a carbon support.

5. The process of claim 4, characterized in that the hydrogenatable precursor is selected from the group consisting of maleic acid; maleic anhydride, fumaric acid, succinic acid, succinic anhydride, maleate esters, succinate esters, gamma-butyrolactone and mixtures thereof.

6. The process of re-indication 4, characterized in that the hydrogenatable precursor is at least one of maleic acid, succinic acid, or gamma-butyrolactone.

7. The process of claim 4, characterized in that the catalyst comprises between about 0.1 to about 20% by weight of palladium, between about 0.1 to about 20% by weight of silver, between about 0.1 to about 20% by weight. rhenium weight, and between about 0.1 to about 5% by weight of at least one of aluminum, cobalt and mixtures thereof.

8. The process of claim 7, characterized in that the catalyst comprises about 2 to 4% by weight of palladium, about 2 to 4% by weight of silver, about 5 to 9% by weight of rhenium, and about 0.2 to about -0.6% by weight of at least one of aluminum, cobalt and mixtures thereof.

9. The process of claim 4, characterized in that the ratio of hydrogen to hydrogenatable precursor is between about 5 to 1 and about 1000 to 1.

10. The process of claim 4, characterized in that the pressure of the nitrogen-containing gas is between about 20 and 400 at a time.

11. The process of claim 4, characterized in that the contact time is between about 0.1 minute and 20 hours.

12. A method for making a catalyst for the production of 1,4-butanediol, characterized in that it comprises: (i) oxidizing a carbon support by contacting the carbon support with an oxidizing agent; (ii) impregnating in one or more impregnation steps comprising contacting a carbon support with a source of palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof; (iii) drying the impregnated carbon support to remove the solvent after each impregnation step; and (iv) heating the impregnated carbon support from room temperature to a temperature between about 100 ° C and about 350 ° C under reduced conditions.

13. The method of claim 12, characterized in that the carbon support is in contact with an oxidizing agent at about the same time as the impregnation of the carbon support with the source of palladium, silver, rhenium and at least one of aluminum, cobalt and mixtures of the same.

14. The method of the rei indication 12, characterized in that the oxidizing agent is selected from the group consisting of nitric acid, hydrogen peroxide, sodium hypochlorite, ammonium persulfate, perchloric acid, and oxygen.

15. The method of claim 12, characterized in that after step (iv) the catalyst is contacted with a hydrogenatable precursor and hydrogen, and heated from room temperature to between about 40 ° C and about 250 ° C.

16. The process of claim 12, wherein the hydrogenatable precursor is selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, succinic acid, succinic anhydride, dimethyl succinate, gamma-butyrolactone, and mixtures of the same.

17. A process for the production of tetrahydrofuran and 1, -bunediol, characterized in that it comprises catalytically hydrogenating a hydrogenatable precursor in contact with a hydrogenation catalyst comprising palladium, silver, rhenium and at least one of aluminum, cobalt and mixtures thereof, in a carbon support wherein the catalyst is prepared by the steps of (i) oxidizing a carbon support by contacting the -carbon support with an oxidizing agent; (ii) impregnating in one or more impregnation steps comprising contacting a carbon support with a source of palladium, silver, rhenium and at least one of iron, aluminum, cobalt and mixtures thereof; (iii) drying the impregnated carbon support to remove the solvent after each impregnation step; and (iv) heating the impregnated carbon support from room temperature to a temperature between about 100 ° C and about 350 ° C under reduced conditions.

18. The process of claim 17, characterized in that the hydrogenatable precursor is selected from the group consisting of maleic acid, maleic anhydride, fumaric acid, succinic acid, succinic anhydride, maleate esters, succinate esters, gamma-butyrolactone and mixtures. thereof.

19. The process of claim 17, characterized in that the hydrogenatable precursor is at least one of maleic acid, succinic acid, or gamma-butyrolactone.

20. The process of claim 17, characterized in that it comprises between about 0.1 to about 20% by weight of palladium, between about 0.1 to about 20% by weight of silver, between about 0.1 to about 20% by weight of Rhenium, and between about 0.1 to about 5% by weight of at least one of aluminum, cobalt and mixtures of the same.

21. The process of claim 17, characterized in that the catalyst comprises about 2 to 4% by weight of palladium, about 2 to 4% by weight of silver, about 5 to 9% by weight of rhenium, and about 0.2 to about -0.6% by weight of at least one of aluminum, cobalt and mixtures thereof.

22. The process of claim 17, characterized in that the ratio of hydrogen to hydrogenatable precursor is between about 5 to 1 and about 1000 to 1.

23. The process of claim 17, characterized in that the pressure of the hydrogen-containing gas is between about 20 and 400 atmospheres.

24. The process of claim 17, characterized in that the contact time is between about 0.1 minute and 20 hours.

25. The method of claim 17, characterized in that the oxidizing agent is selected from the group consisting of nitric acid, hydrogen peroxide, sodium hypochlorite, ammonium persulfate, perchloric acid, and oxygen.