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Publication numberUS2782243 A
Publication typeGrant
Publication dateFeb 19, 1957
Filing dateMar 29, 1954
Priority dateMar 29, 1954
Publication numberUS 2782243 A, US 2782243A, US-A-2782243, US2782243 A, US2782243A
InventorsLawrence G Hess, Helmut W Schulz
Original AssigneeUnion Carbide & Carbon Corp
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Hydrogenation of esters
US 2782243 A
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Description  (OCR text may contain errors)

United States Patent HYDROGENATION 0F ESTERS Lawrence G. Hess and Helmut W. Schulz, Charleston,

W. Va., assignors to Union Carbide and Carbon Corporation, a corporation of New York No Drawing. Application March 29, 1954,

Serial No. 419,575

7 Claims. (Cl. 260-638) This invention relates to the production of lower aliphatic alcohols by the hydrogenation of esters under the influence of a catalyst and more particularly this invention is directed to a process for the production of loweraliphatic monohydric alcohols from esters embodying the same by the hydrogenation of these esters in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and containing from 1 to 5 parts of chromium per 100 parts of copper.

One of the significant features of this invention is that now a process is available commercially which will permit the production of ethanol and methanol in substantial yield by the vapor phase hydrogenation of methyl acetate at a temperature above its critical temperature and at an elevated pressure in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and containing from 1 to 5 parts of chromium per 100 parts of copper.

Heretofore, ethanol and methanol have not been produced by the reaction of hydrogen with methyl acetate, but it is known that alcohols of higher molecular weight may be produced by the catalytic hydrogenation of esters of aliphatic carboxylic acids, utilizing various catalysts such as, for example, copper oxide preferably promoted with an oxide of an alkali or alkaline earth metal; chromium oxide alone or in conjunction with tungstates, vanadates or molybdates; cobalt salts of metal acids deposited on a carrier; reduced copper oxide alone or in conjunction with oxides of zinc, magnesium, manganese and the like. All of these heretofore known processes are essentially liquid phase operations and although vapor phase operations have been proposed they have not been eflicient and the yields of products are low.

While the processes of hydrogenating esters of aliphatic monocarboxylic acids are thoroughly discussed in the literature, the particular processes for hydrogenating methyl acetate to ethanol and methanol are few in number. The reason appears to be that methyl acetate and methanol are subject to gaseous decomposition during the hydrogenation processes utilized by the prior art. Thus, no suitable commercial processes exist for the conversion of methyl acetate to ethanol and methanol.

Therefore, it is one of the purposes of this invention to provide an essentially vapor phase process for the conversion of methyl acetate to ethanol and methanol which is highly efficient and results in substantial yields of products.

The process of this invention, however, in its broader aspects comprises the reaction of lower aliphatic esters in the presence of hydrogen at. an elevated temperature and pressure in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and con- Theoretically, the reaction calls for two mols of hydrogen per mol of ester but from a practical standpoint the ester is charged to the reaction vessel and reacted in a large excess of hydrogen.

The lower aliphatic esters which may be employed in the process of this invention can be esters such as, methyl acetate, ethyl acetate, methyl and ethyl propionate, methyl and ethyl butyrate and the like.

The hydrogenolysis conditions which may be advantageously employed in the process of this invention are similar to those conditions of hydrogenation which are generally employed in established hydrogenation techniques and are widely known as involving the use of elevated temperatures and pressures.

More specifically, though, it is preferred to employ an elevated temperature which is in the range of 250 C. to 400 C.

Pressures above 5,000 pounds per square inch are employed, excellent results being obtained when pressures in the range of 10,000-l5,000 pounds per square inch are utilized.

. it is then roasted to produce a finished catalyst containing from 1 to 5 parts of chromium per 100 parts of copper.

A detailed example of the preparation of the catalyst in a preferred form involves the addition of approximately 6.6 parts by weight of copper scrap overa three and until the acidity falls below 2.0 percent.

taining from 1 to 5 parts of chromium per 100 parts 7 of copper.

The reaction whereby the alcohols are produced in accordance with this invention may be represented, in the case of methyl acetate, by the following equation:

hour period to 100 parts by weight of a 34 percent aqueous nitric acid solution maintained at a temperature of C. When the acidity of the resulting copper nitrate solution is below 20 percent, calculated as nitric acid, 0.45 part of chromium is added as a concentrated aque ous chromium acetate solution. Then 6.5 additional parts of copper scrap are added over a period of three hours. The solution temperature is maintained at 90 C. by cooling or heating as required during all additions The copper-chrome solution is then concentrated by evaporation until a specific gravity of 1.70-1.75 is obtained.

Preferably, a catalyst support should be employed in which case a suitable porous basket containing 0.375 x 0.261 mesh Filtros is immersed for 15 minutes in the impregnating solution having a specific gravity of 1.70- 1.75 at the boiling temperature. After dipping and drainage the impregnated Filtros is roasted in a stream of air for a period of two hours at 350 C.

The catalyst is then dipped and roasted until the copper content is 12 percent and the chromium content is 0.3 to 0.4 percent, giving a weight ratio of 2.5-3.5 parts of chromium per parts of copper.

The amount of catalyst necessary to promote the hydrogenation of methyl acetate is not a critical feature of this invention. An amount of catalyst suificient to promote the reaction is all that is necessary. For batchwise reactions, however, a preferred range of catalyst concentration based on copper oxide is an amount equivalent to l to 5 percent, by weight, of the ester charged to the reaction vessel. The catalyst may or may not be supported by an inert carrier and may be charged in a loose form to the reaction vessel or suspended in a porous basket within the reaction vessel; :For continuous reactions the amount of catalyst required depends upon the desired conversion and production rate, the supported catalyst being heated within a high pressure reactor and the vaporized lower aliphatic esters being passed together with hydrogen through the catalyst bed.

In carrying out the process of this invention, a rockertype reaction vessel similar to those used in established techniques for laboratory hydrogenations can be utilized although, as indicated above, the process can be operated in a continuous or semi-continuous manner. Methyl acetate, or the other lower aliphatic esters, may be hydrogenated in solution with one of the expected alcohols or an inert diluent by passing the reactants over a supported catalyst in the vapor phase.

In batchwise experiments the reaction vessel is charged with liquid and solid components and hydrogen is introduced at approximately 500 pounds per square inch pressure and expelled three times to purge the system completely. Hydrogen is then added to the reaction vessel to a pressure calculated to give the desired reaction pressure and the reaction vessel is heated to the desire-d operating temperature, the reaction system being maintained at the desired operating pressure. When the reaction conditions have been maintained for a sufficient period of time, the heating is discontinued and the reaction vessel and its contents cooled. The products are then discharged from the reaction vessel and recovered by any suitable means, such as for example, by fractional distillation.

The following examples will serve to illustrate the practice of the invention:

Example I Methyl acetate, as an 82 percent solution with methanol, was reacted in a pressure-resistant reaction vessel with hydrogen at a pressure of 15,000 pounds per square inch for a period of two hours at a temperature of 270 C. using 2 percent by weight, based on contained copper, of the supported catalyst described above. A methyl acetate conversion of 89.5 percent was obtained with an efiiciency to methanol and ethanol of 91.4 percent and 96.4 percent, respectively. The production ratio based on the methanol and ethanol recovered was equivalent to 175 pounds of product per cubic foot of catalyst volume per hour.

Example II Methyl acetate, as an 82 percent solution with methanol, was reacted in a pressure-resistant reaction vessel with hydrogen at a pressure of 10,000 pounds per square inch for a period of two hours and at a temperature of 270 C. using 3 percent by weight, based on contained copper, of the supported catalyst described above. A methyl acetate conversion of 81.8 percent was obtained with an efficiency to methanol and ethanol of 82.6 percent and 83.5 percent, respectively. The production ratio based on the combined Weight of methanol and ethanol produced was 90 pounds per cubic foot of supported catalyst per hour.

Example III Approximately 350 grams of ethyl propionate were heated to 290 C. in a pressure-resistant vessel in the presence of 125 grams of the supported copper-chrome catalyst described above and under an initial hydrogen pressure of 5300 pounds per square inch. A temperature of 290 C. and a pressure t 15,000 pounds per square inch were maintained for a period of one hour. After the vessel and its contents had been cooled, the crude reaction product was discharged. Distillation and analysis of the fractions showed an ethyl propionate conversion of 80.4 percent and an efficiency to ethanol and npropanol of 82.5 percent and 90.4 percent, respectively, based on the ethyl propionate charged. The production ratio based on the combined weight of ethanol and propanol produced was 125 pounds per cubic foot of supported catalyst per hour.

What is claimed is: t

1. A process for the production of alcohols from esters which comprises reacting a lower aliphatic ester with hydrogen under hydrogenating conditions in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and containing from 1 to 5 parts of chromium per parts of copper.

2. A process for the production of methanol and ethanol which comprises reacting methyl acetate with hydrogen under hydrogenating conditions in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and containing from 1 to 5 parts of chromium per 100 parts of copper.

3. A process for the production of ethanol and propanol which comprises reacting ethyl propionate with hydrogen under hydrogenating conditions in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and containing from 1 to 5 parts of chromium per 100 parts of copper.

4. A process of the production of alcohols from esters which comprises reacting a lower aliphatic ester with hydrogen at a temperature in the range 250 C. to 400 C. and a pressure in the range 5,000 to 15,000 pounds per square inch in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and containing from 1 to 5 parts of chromium per 100 parts of copper.

5. A process for the production of methanol and ethanol which comprises reacting methyl acetate with hydrogen at a temperature in the range 250 C. to 400 C. and a pressure in the range 5,000 to 15,000 pounds per square inch in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and containing from 1 to 5 parts of chromium per 100 parts of copper.

6. A process for the production of ethanol and propanol which comprises reacting ethyl propionate with hydrogen at a temperature in the range 250 C. to 400 C. and a pressure in the range 5,000 to 15,000 pounds per square inch in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and containing from 1 to 5 parts of chromium per 100 parts of copper.

7. In a process of hydrogenating a lower aliphatic ester to the corresponding alcohol, the improvement which comprises reacting the lower aliphatic ester with hydrogen at an elevated temperature and pressure in the presence of a catalyst consisting of copper oxide promoted with chromium oxide and containing from 1 to 5 parts of chromium per 100 parts of copper.

References Cited in the file of this patent UNITED STATES PATENTS 1,302,011 Christiansen Apr. 29, 1919 1,605,093 Bouvier et al. Nov. 2, 1926 1,977,750 Young Oct. 23, 1934 2,004,135 Rothrock June 11, 1935 2,040,944 Lazier May 9, 1936 2,079,414 Lazier May 4, 1937 2,091,800 Adkins Aug. 31,1937 2,544,771 Young et al. Mar. 13, 1951 2,575,403 Young et al. Nov. 20, 1951 FOREIGN PATENTS 844,891 Germany July 24, 1952 OTHER REFERENCES Adkins et al.: I. A. C. 8., vol. 72 (1950).

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1302011 *Dec 6, 1918Apr 29, 1919Jens Anton ChristiansenMethod of producing methyl alcohol from alkyl formates.
US1605093 *Sep 18, 1923Nov 2, 1926Ste Chim Usines RhoneProcess for the reduction of alkyl esters
US1977750 *Dec 7, 1931Oct 23, 1934Carbide & Carbon Chem CorpProcess for making acetaldehyde and a catalyst therefor
US2004135 *Dec 23, 1932Jun 11, 1935Du PontProduction of polyhydric alcohols
US2040944 *Sep 22, 1933May 19, 1936Du PontProcess for producing polyhydroxy alcohols
US2079414 *Aug 20, 1932May 4, 1937Du PontProcess for producing alcohols from esters of nonaromatic carboxylic acids
US2091800 *Sep 15, 1931Aug 31, 1937Rohm & HaasMethod of hydrogenating esters
US2544771 *Oct 14, 1943Mar 13, 1951Union Carbide & Carbon CorpCopper-chromium hydrogenation catalyst
US2575403 *Jun 14, 1947Nov 20, 1951Union Carbide & Carbon CorpCatalytic hydrogenation of acetophenone to phenyl methyl carbinol
DE844891C *Jul 19, 1944Jul 24, 1952Basf AgVerfahren zur Herstellung von primaeren Alkoholen
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2965562 *Dec 9, 1957Dec 20, 1960Phillips Petroleum CoHydrocracking hydrocarbon oils with a catalyst composite, comprising chromium sesquioxide and reduced cupric oxide
US3180898 *Apr 17, 1961Apr 27, 1965Metallgesellschaft AgProcess for the production of fatty alcohols by catalytic hydrogenation of fatty acids and their derivatives
US4199479 *Feb 24, 1978Apr 22, 1980Chevron Research CompanyHydrogenation catalyst
US4398039 *May 18, 1981Aug 9, 1983The Standard Oil CompanyHydrogenation of carboxylic acids
US4443639 *Sep 13, 1982Apr 17, 1984The Standard Oil Company (Indiana)Vapor phase, water, mixed oxide catalyst with ruthenium and cobalt and/or nickel
US4454358 *Jan 7, 1982Jun 12, 1984Basf AktiengesellschaftContinuous production of ethanol and plural stage distillation of the same
US4990682 *Nov 21, 1989Feb 5, 1991Huels AgProcess for the preparation of 5-chloro-2-pentanone
US5134108 *May 22, 1991Jul 28, 1992Engelhard CorporationHydrogenation catlaysts
US5155086 *Apr 2, 1991Oct 13, 1992Engelhard CorporationPowder of copper, zinc, aluminum oxides
US5345005 *Sep 18, 1992Sep 6, 1994Engelhard CorporationHydrogenation catalyst, process for preparing and process of using said catalyst
US6054627 *May 27, 1992Apr 25, 2000Engelhard CorporationHydrogenation catalyst, process for preparing and process of using said catalyst
US7351559Jun 29, 2005Apr 1, 2008Zeachem, Inc.Process for producing ethanol
US7507562Jan 24, 2006Mar 24, 2009Zeachem, Inc.yeast fermentation of corn to produce ethanol, then distilling the ethanol to produce bottoms, hydrolyzing the bottoms, separating the hydrolyzed bottoms into a solids fraction and liquid hydrolyzates and culturing microorganism in the liquid hydrolyzate to produce acetic acid, esters and/or mixtures
US7601865Jan 28, 2005Oct 13, 2009Zeachem, Inc.Introducing tertiary amine and CO2 to dilute salt solution to form acid/amine complex and insoluble carbonate salt, introducing water immiscible solvent to dilute salt solution to form reaction phase, continuously drying reaction phase and forming product
US7682812Mar 19, 2008Mar 23, 2010Zeachem, Inc.Process for producing ethanol
US7888082Nov 26, 2008Feb 15, 2011Zeachem, Inc.Process for producing ethanol from corn dry milling
US7964379Jan 26, 2010Jun 21, 2011Zeachem, Inc.Process for producing ethanol
US8048655Aug 26, 2009Nov 1, 2011Zeachem, Inc.Recovery of organic acids
US8236534May 5, 2011Aug 7, 2012Zeachem, Inc.Process for producing ethanol
US8252567Feb 9, 2009Aug 28, 2012Zeachem, Inc.Method for the indirect production of butanol and hexanol
US8329436Feb 11, 2008Dec 11, 2012Zeachem, Inc.Thermochemical conversion of biomass
EP0056488A2 *Dec 23, 1981Jul 28, 1982BASF AktiengesellschaftContinuous process for the production of ethanol
EP2011879A2Mar 10, 2000Jan 7, 2009Zeachem, Inc.Process for producing ethanol
Classifications
U.S. Classification568/885, 502/318
International ClassificationC07C29/149
Cooperative ClassificationC07C29/149
European ClassificationC07C29/149