JP4486751B2 - Catalyst system for one-stage gas phase production of acetic acid from ethylene - Google Patents

Description

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【表２】

【００１８】
本発明を使用して示される上記の結果から、下記の驚くべき且つ予想外の利点を得ることができる。
１．エチレンの高い活性／転化は、アルケンの部分酸化の高い速度を反映している。
２．本発明は、酢酸へのエチレンの酸化の高い速度を与える。
３．本発明は、ＣＯｘ生成物への全酸化の低い速度を与える。
４．供給物の中に水を添加することによって、酸化生成物である酢酸への活性及び選択率が増加し、一方、ＣＯｘ生成物が減少し、この影響の大きさは、使用する水の量に依存する。
本発明の上記の説明は、例示であり限定でないことを意図する。説明した実施形態に於ける種々の変更又は修正は、当業者に生じ得る。これらは本発明の精神及び範囲から逸脱することなくすることができる。[0001]
(Background of the Invention)
(Field of Invention)
The present invention relates to an improved catalyst system containing MoVNbPd, MoVLaPd and combinations thereof and an improved catalytic process for the low temperature selective oxygenation of ethylene to acetic acid. More particularly, the present invention relates to a single step catalytic process using a novel catalyst to provide high ethylene conversion and acetic acid yield.
[0002]
(Description of related technology)
Several publications are referenced in this patent application. These references describe the state of the art to which this invention pertains and are incorporated herein by reference.
Acetic acid is generally produced by methanol carbonylation using an expensive rhodium catalyst in a liquid phase homogeneous reaction. This method requires complex procedures for catalyst recovery and product isolation. Furthermore, the presence of iodine at the ppm level in the final product has a negative impact on the use of acetic acid produced by this method.
Acetic acid is also produced by a two-stage acetaldehyde method using a manganese catalyst. Such methods are disclosed in U.S. Pat. Nos. 3,131,223, 3,057,915, 3,301,905 and 3,240,805. The first stage of the process involves the production of acetaldehyde from ethylene. The economics of this method are not advantageous due to the costs arising from the two stages. Furthermore, these methods produce large amounts of acetaldehyde as a by-product. Furthermore, large amounts of ethylene will be lost due to complete oxidation to carbon dioxide.
More recently, Showa Denko [European Patent No. 0 62 0205 A1] describes phosphorous, silicon, boron, aluminum, germanium, titanium, zirconium, cerium, cobalt, chromium and metallic palladium, and groups XI and XIV of the periodic table. Relates to a catalytic process for the conversion of ethylene to acetic acid using a catalyst containing a heteropolyacid with at least one element selected from the group XV, XV and XVI. One-pass conversion of ethylene has been reported to produce significant amounts of acetaldehyde that are very low on these heteropoly catalysts and can have a significant impact on separation costs. The catalyst system used in the present invention is different from the Showa Denko catalyst.
European Patent No. A0 29 4845 is in contact with a physical mixture of at least two catalyst systems comprising (A) a catalyst for oxydehydrogenation of ethane to ethylene and (B) a catalyst for hydration / oxidation of ethylene. And is concerned with a highly selective process for the production of acetic acid by oxidizing ethane or ethylene with oxygen. The ethaneoxy dehydrogenation catalyst has the formula MoxVyZz, where Z is metal, Nb, Sb, Ta, Ca, Sr, Ti, W, Li, Na, Be, Mg, Zn, Cd, Hg, Sc, Fe and Ni 1 type or 2 types or more). The catalyst for hydration / oxidation is selected from a molecular sieve catalyst, a palladium-containing oxide catalyst, a tungsten-phosphorus oxide catalyst or a tin or molybdenum-containing oxide catalyst. European Patent No. A0 29 4845 uses a catalyst produced by physical mixing of two catalysts.
Japanese Patent No. 46-6763 describes the following metal atom combinations: V-Pd-Sb, V-Rh-Sb, V-Pd-P, V-Rh-P, V-Rh-As, V- Use the special catalysts disclosed in the Examples, including Pd-As, Mo-Pd-Sb, Mo-Rh-Sb, Mo-Rh-As and Mo-P-W-Pd-Rh-Sb. Related to the catalytic oxidation of ethylene to acetic acid.
Japanese Patent 54-57488 relates to the use of a NaPdH2-PMoV catalyst for the oxidation of ethylene to acetic acid.
Syoji Tan et al. [J. Catal. 17: 132-142, 1970] reported that olefins oxidize to ketones over the two-component catalyst systems Co ₃ O ₄ —MoO ₃ and SnO ₂ —MoO ₃ . This document discloses the production of acetic acid as a by-product along with other compounds, and in particular the product of ethylene was only carbon dioxide.
Thus, any of the prior art is a bifunctional catalyst, from ethylene using a catalyst designed in such a way that it improves the activation function and the selectivity to the desired product acetic acid. It does not disclose or suggest the advantages of the catalyst system disclosed in the present invention for the selective production of acetic acid.
[0003]
(Object of invention)
The object of the present invention is to overcome the above-identified drawbacks.
Another object of the present invention is to provide an improved catalyst system for the production of acetic acid.
Yet another object of the present invention is to provide an improved process for the production of acetic acid with improved selectivity and yield of the desired product acetic acid.
Yet another object of the present invention is to provide an improved process for producing a catalyst for the production of acetic acid.
The foregoing and other objects and advantages of the invention will be set forth in or apparent from the description that follows.
[0004]
(Summary of the Invention)
The present invention is a gas phase reaction, with relatively high levels of conversion, selectivity and productivity, with molecular oxygen to acetic acid at temperatures in the range of 150 ° C. to 450 ° C. and pressures of 1 to 50 bar. It relates to the selective oxidation of ethylene. This is achieved by using mixed metal oxides, including supported or unsupported MoVNbPd or MoVLaPd oxide catalysts.
[0005]
(Description of Preferred Embodiment)
For the oxidation catalyst, the selectivity behavior to the desired partial oxidation product is determined by other physical reactions such as (a) hydrocarbon to oxygen ratio, (b) pressure, (c) reaction temperature and (d) contact time. In addition to the parameters, it depends on the type of active center in the catalyst.
In general, it is known that the selectivity for light oxidation products such as acetic acid increases when the reaction temperature decreases, while the yield decreases for total conversion. The active site involved in the reaction plays an important role in the direction of the reaction. Furthermore, the selectivity for the partial oxidation product depends on the reactivity of the lattice oxygen to form C—O bonds with the adsorbed hydrocarbons. For example, alkenes are more reactive and preferentially adsorb on metal oxide / acidic catalysts compared to alkanes. The mixed metal oxide phase of MoV is known to be responsible for the activity of hydrocarbons, and the activity of the catalyst depends on the relative number of V ⁺⁴ and V ⁺⁵ on the surface of the catalyst. In addition, palladium is known as a total metal oxide as well as a metal that helps facilitate the oxidation of alkenes. The optimum amount of Pd with a high degree of metal dispersion on the mixed metal oxide catalyst results in a high selectivity to acetic acid.
Furthermore, the addition of water as a co-feed plays an important role as a reaction diluent and as a heat regulator for the reaction, and as a desorption accelerator for reaction products in a vapor phase oxidation reaction or as an acetic acid. It acts to mask the sites responsible for the total oxidation resulting in an increased yield of.
In carrying out the partial oxidation of the ethylene process, the reaction mixture preferably contains 1 mol of ethylene, 0.01 to 2.0 mol of molecular oxygen (in the form of pure oxygen or air) and zero to 5 Contains water in the form of 0.0 moles of steam. Other gases such as helium, nitrogen and carbon dioxide can be used as reaction diluents or thermal modifiers.
The gaseous components of the reaction mixture preferably include ethylene, oxygen and diluent, and these components can be mixed uniformly before being introduced into the reaction zone. The components can be preheated individually or after mixing prior to introduction into the reaction zone, and the reaction zone must have a temperature of from about 150 ° C to about 450 ° C.
The reaction zone is preferably 1 to 50 bar, more preferably 1 to 30 bar pressure, about 150 ° C. to about 450 ° C., more preferably 200 ° C. to 300 ° C., about 0.1 sec to 100 sec, More preferably, the contact time between the reaction mixture and the catalyst of 0.1 seconds to 10 seconds and about 50 to about 50,000 hours ⁻¹ , more preferably 100 to 10,000 hours ⁻¹ , most preferably 200 to It has a time-based space velocity of 3,000 hours- ¹ .
Contact time is defined as the ratio between the apparent volume of the catalyst bed in units of time and the volume of the gaseous reaction mixture fed to the catalyst bed under the given reaction conditions.
The space velocity is calculated by determining the total reactor outlet gas equivalent in liters of total emissions generated over 1 hour divided by liters of catalyst in the reactor. This chamber temperature volume is converted to a volume at 1 bar at 0 ° C.
The reaction pressure is initially provided by the gaseous reactant and diluent feed and should be maintained by using an appropriate back pressure regulator installed in the reactor outlet stream after the reaction has begun. Can do.
The reaction temperature can be provided by installing the catalyst bed in a tubular converter having walls installed in a circulating sand bath furnace heated to the desired reaction temperature.
The oxygen concentration in the feed gas mixture can vary widely from 0.1 to 50% or more of the feed mixture by applying an appropriate measure to avoid explosion problems. Air is a preferred source of oxygen in the feed. The amount of oxygen present may be a stoichiometric amount of hydrocarbons in the feed or less.
This process is generally carried out in one step with oxygen and all of the reactants fed as a single feed and the unreacted initial reactant is recycled. However, it is also possible to use a multistage addition of oxygen to the reactor with an intermediate hydrocarbon feed. This will improve productivity to acetic acid and avoid potential hazardous conditions.
[0006]
(Example)
The following examples are illustrative of some of the products that fall within the scope of the present invention and how to make them. Of course, these should not be considered a limitation of the present invention in any way. Numerous changes and modifications can be made with respect to the present invention.
In order to illustrate the present invention, several examples were carried out using the two catalyst compositions shown below.
Catalyst A Mo ₁ V _0.396 Nb _0.128 Pd _{3.84 E-04}
Catalyst B M _o 1V _0.628 Pd _{2.88 E-04} La _{1.0 E-05}
[0007]
Manufacturing Procedure for Catalyst A: An amount of 11.4 grams of ammonium metavanadate (Aldrich Chemicals, analysis = 99.0%) was added to 120 mL of distilled water and stirred at 90 ° C. Until heated. 2.5 grams of oxalic acid was added to give a clear yellow solution (solution A) having a pH between 5 and 6. 19.4 grams of niobium oxalate (21.5% Nb2O5, Niobium Products Company, USA) was added to 86 mL of water and heated to 65 ° C. with continuous stirring. A clear white solution (solution B) having a pH of was obtained. Solution B was then combined with Solution A. The resulting solution was heated at 90 ° C. and 28 grams of oxalic acid was added very slowly with continuous stirring to obtain Solution C. An amount of 43.2 grams of ammonium paramolybdate tetrahydrate (Aldrich Chemicals, Inc. AC 12054-85-2) was added to 45 mL of water and heated to 60 ° C. A colorless solution (solution D) having a pH between 0.0 and 6.5 was obtained. Solution D was slowly combined with Solution C to give a dark blue to dark gray precipitate (mixture E). The required amount of palladium was added slowly to allow the mixture to gel. The black combination was stirred vigorously to obtain a uniform gel mixture, which was then slowly dried to initial dryness with continuous stirring at 95-98 ° C. within 60-120 minutes.
The resulting solid was placed in a porcelain dish and further dried in an oven at 120 ° C. for 16 hours. The dried material was allowed to cool to room temperature and placed in a furnace. The temperature was increased from room temperature to 350 ° C. at a rate of 2 ° / min and then maintained at 350 ° C. for 4 hours.
The calcined catalyst was blended into uniform particles of 40-60 mesh size and evaluated for ethane oxidative dehydrogenation.
[0008]
Manufacturing Procedure for Catalyst B: An amount of 6 grams of ammonium metavanadate (Aldrich Chemicals, analysis = 99.0%) was added to 65 mL of distilled water and heated to 90 ° C. with stirring. 6 grams of oxalic acid was added to the above solution. At 80 ° C. at pH 2 to 2.5, the color of the solution changes from yellowish green to dark brown (Solution A). A quantity of 14.4 grams of ammonium paramolybdate tetrahydrate (Aldrich Chemicals, Inc. AC 12054-85-2) was added to 16.7 mL of water and heated to 60-65 ° C. A colorless solution (solution B) having a pH between 5.0 and 6.0 was obtained. Solution A was slowly mixed with solution B to give a dark blue to dark gray precipitate (mixture E). The required amount of palladium followed by lanthanum nitrate was added slowly to allow the mixture to gel. The black combination was stirred vigorously to obtain a uniform gel mixture, which was then slowly dried to initial dryness with continuous stirring at 95-98 ° C. within 60-120 minutes.
The resulting solid was placed in a porcelain dish and further dried in an oven at 120 ° C. for 16 hours. The dried material was allowed to cool to room temperature and placed in a furnace. The temperature was increased from room temperature to 350 ° C. at a rate of 2 ° / min and then maintained at 350 ° C. for 4 hours.
The calcined catalyst was blended into uniform particles of 40-60 mesh size and evaluated for ethane oxidative dehydrogenation.
Catalyst A was used for Examples 1-5, while Catalyst B was used for Examples 6 and 7.
The reaction product was analyzed by gas chromatography online. Oxygen, nitrogen, and carbon monoxide were analyzed using a 13 × molecular sieve 2.5 m × 3 mm column. Carbon dioxide and ethylene were analyzed using a 0.5 m × 3 mm column packed with material sold under the trade name PORAPACK® N. Acetic acid and water were analyzed using a 1.5 m × 3 mm column packed with material sold under the trade name HAYASEP® Q. In all cases, conversion and selectivity calculations were based on the following stoichiometry.
C ₂ H ₄ + O ₂ → C ₂ H ₄ O ₂
C ₂ H ₄ + 2O ₂ → 2CO + 3H ₂ O
C ₂ H ₄ + 3O ₂ → 2CO ₂ + 3H ₂ O
The acetic acid yield was calculated by multiplying the selectivity to acetic acid by the ethylene conversion.
[0009]
Example 1
A stainless steel tube reactor measuring 0.760 cm (inner diameter) × 46 cm (length) is charged with 1 g of calcined catalyst A (40-60 mesh) and diluted with 3 g of silicon dioxide of the same mesh size. did. The reactor was then heated to 285 ° C. in a sand bath thermostatic oven and pressurized to 200 psi with nitrogen. A gas feed containing 14.79% ethylene and 85.21% air by volume was fed to the reactor at a flow rate of 58.30 cc / min. The liquid product was condensed in a cold trap and the gas product was analyzed with an on-line GC system.
[0010]
Example 2
A stainless steel tube reactor measuring 0.760 cm (inner diameter) × 46 cm (length) is charged with 1 g of calcined catalyst A (40-60 mesh) and diluted with 3 g of silicon dioxide of the same mesh size. did. The reactor was then heated to 285 ° C. in a sand bath thermostatic oven and pressurized to 200 psi with nitrogen. A gas feed containing 14.94% ethylene and 85.06% air by volume was fed to the reactor at a flow rate of 60.40 cc / min. Water (8.85 cc / min, calculated as gas at STP) was also fed to the reactor inlet. The liquid product was condensed in a cold trap and the gas product was analyzed with an on-line GC system.
[0011]
Example 3
A stainless steel tube reactor measuring 0.760 cm (inner diameter) × 46 cm (length) is charged with 1 g of calcined catalyst A (40-60 mesh) and diluted with 3 g of silicon dioxide of the same mesh size. did. The reactor was then heated to 285 ° C. in a sand bath thermostatic oven and pressurized to 200 psi with nitrogen. A gas feed containing 15% ethylene and 85% air by volume was fed to the reactor at a flow rate of 91.33 cc / min. The liquid product was condensed in a cold trap and the gas product was analyzed with an on-line GC system.
[0012]
Example 4
A stainless steel tube reactor measuring 0.760 cm (inner diameter) × 46 cm (length) is charged with 1 g of calcined catalyst A (40-60 mesh) and diluted with 3 g of silicon dioxide of the same mesh size. did. The reactor was then heated to 285 ° C. in a sand bath thermostatic oven and pressurized to 200 psi with nitrogen. A gas feed containing 15% ethylene and 85% air by volume was fed to the reactor at a flow rate of 90.60 cc / min. Water (9.17 cc / min, calculated as gas at STP) was also fed to the reactor inlet. The liquid product was condensed in a cold trap and the gas product was analyzed with an on-line GC system.
[0013]
Example 5
A stainless steel tubular reactor measuring 0.760 cm (inner diameter) x 46 cm (length) was charged with 7 g of calcined catalyst A (40-60 mesh) and diluted with 3 g of silicon dioxide of the same mesh size. did. The reactor was then heated to 240 ° C. in a furnace with a sand bath thermostat and pressurized to 250 psi with nitrogen. A gas feed containing 10.10% ethylene and 89.9% air by volume was fed to the reactor at a flow rate of 35.33 cc / min. The liquid product was condensed in a cold trap and the gas product was analyzed with an on-line GC system.
[0014]
Example 6
A stainless steel tube reactor measuring 0.760 cm (inner diameter) × 46 cm (length) is charged with 1 g of calcined catalyst B (40-60 mesh) and diluted with 3 g of silicon dioxide of the same mesh size. did. The reactor was then heated to 285 ° C. in a sand bath thermostatic oven and pressurized to 200 psi with nitrogen. A gas feed containing 14.16% ethylene and 85.84% air by volume was fed to the reactor at a flow rate of 59.80 cc / min. Water (9.16 cc / min, calculated as gas at STP) was also fed to the reactor inlet. The liquid product was condensed in a cold trap and the gas product was analyzed with an on-line GC system.
[0015]
Example 7
A stainless steel tube reactor measuring 0.760 cm (inner diameter) × 46 cm (length) is charged with 1 g of calcined catalyst B (40-60 mesh) and diluted with 3 g of silicon dioxide of the same mesh size. did. The reactor was then heated to 285 ° C. in a sand bath thermostatic oven and pressurized to 200 psi with nitrogen. A gas feed containing 14.31% ethylene and 85.69% air by volume was fed to the reactor at a flow rate of 59.90 cc / min. The liquid product was condensed in a cold trap and the gas product was analyzed with an on-line GC system.
The results of tests on catalysts A and B under the reaction conditions described above are shown in Table I, and a typical analysis of condensed products containing impurities is shown in Table II.
[0016]
[Table 1]

[0017]
[Table 2]

[0018]
From the above results shown using the present invention, the following surprising and unexpected advantages can be obtained.
1. The high ethylene activity / conversion reflects the high rate of partial oxidation of alkenes.
2. The present invention provides a high rate of ethylene oxidation to acetic acid.
3. The present invention provides a low rate of total oxidation to the COx product.
4). The addition of water into the feed increases the activity and selectivity to the oxidation product acetic acid while reducing the COx product, the magnitude of this effect being dependent on the amount of water used. Dependent.
The above description of the present invention is intended to be illustrative and not limiting. Various changes or modifications in the described embodiments may occur to those skilled in the art. These can be made without departing from the spirit and scope of the invention.

Claims (17)

A reaction mixture containing ethylene and oxygen or a compound capable of providing oxygen in the reaction zone are converted from ethylene to acetic acid in the presence of a supported or unsupported mixed metal oxide catalyst consisting of MoVLaPd. comprising contacting in a sufficient reaction temperature for conversion, stage-step process for ethylene selective oxidation to acetic acid.   The process of claim 1 wherein the catalyst is in the form of a fixed bed or fluidized bed.   The method according to claim 1, wherein the mixture further contains steam.   The method according to claim 1, wherein the reaction mixture further contains air.   The process of claim 1 wherein the reaction contains oxygen.   The process of claim 1, wherein the mixture is a feed mixture introduced into the reaction zone.   The process according to claim 1, wherein the mixture contains molecular oxygen in the range of 0.1 to 50% by volume of the feed mixture.   The method of claim 1, wherein the mixture is diluted with an amount of water / steam in the range of 0-50% by volume of the feed mixture.   The process of claim 1 wherein the ethylene is in vapor form.   The method according to claim 1, wherein the reaction temperature is 150 to 450 ° C.   The process according to claim 1, wherein the reaction zone is under a pressure of 1 to 50 bar.   The process of claim 1 wherein the contacting provides a contact time between the reaction mixture and the catalyst of 0.1 to 10 seconds.   The process of claim 1, wherein the oxidation provides a 70% yield of acetic acid per pass through the reaction zone.   The process of claim 1 wherein the oxidation provides 1400 STY (g acetic acid / L catalyst / hour) per pass through the reaction zone.   The method of claim 1, wherein the oxidation of ethylene produces less than 5 ppm acetaldehyde.   The process according to claim 1, wherein the mixture contains more than 10% by volume of ethylene.   The method of claim 1 further comprising multiple stages of introduction of air or oxygen into the reaction zone to increase acetic acid yield, selectivity, or a combination of yield and selectivity.