Catalytic Hydrogenation

This is a continuation of the application Ser. U.S. Patent No. 874,805, filed on Jun. 13, 1986, which is hereby incorporated herein. U.S. Patent No. 659,904, filed on Oct. 11, 1984, it is the continuation of the application Ser. U.S. Patent No. 409,933, filed on August 20, 1982, which is incorporated herein by reference. US Patent No. 294,519, filed on August 20, 1981 completely waived.

 

This invention relates to catalytic hydrogenation, and more particularly to the catalytic hydrogenation of aliphatic aldehydes.

 

Catalytic hydrogenation of aldehydes to form the corresponding alcohols is a well known reaction and has been widely practiced on a commercial scale. For example, n-butyraldehyde, which is usually synthesized by oxo synthesis of propylene, is subjected to large-scale catalytic hydrogenation to form n-butanol, and 2-ethylpropyl acrolein is formed, for example, by aldol condensation of n-butyraldehyde to form 2-ethyl group. The -3-hydroxyhexanal is subsequently dehydrated and reduced by a considerable amount per ton per year to form the plasticizer alcohol 2-ethylhexanol.

 

The gas phase hydrogenation of an aliphatic aldehyde such as 3,5,5-trimethylhexanal using a catalyst comprising reduced copper plus zinc oxide is described in U.S. Patent No. 5,200,5,000. The temperature is from 150 ° C to 250 ° C and the pressure is from 200 to 600 p.s.i.g. (Absolute pressure is about 15 to 43 kg / cm2). 3,5,5-trimethylhexanal is usually obtained by using a cobalt naphthenate catalyst for diisobutylene (ie 2,4,4-trimethyl-1-pentene and 2,4,4-trimethyl- The resulting crude product obtained by hydroformylation of a mixture of 2-pentene contains 63% of the desired aldehyde, 12% of the impurities, 12% of isooctane and 13% of unreacted diisobutylene. It is then distilled to produce a substantially pure aldehyde, or treated by steam or vacuum distillation to produce 77% of 3,5,5-trimethylhexanal and 7.3% of 3,5,5-trimethyl. Semi-refined aldehyde fraction of caproic acid. Crude, semi-refined or refined aldehydes are used as starting materials for the hydrogenation process. The prior art teaches to increase the alcohol yield by using a crude or semi-refined fraction comprising a substance other than the aldehyde itself which is converted to the desired alcohol by hydrogenation, ie 3 , 5,5-trimethylhexanol; these substances include 3,5,5-trimethylhexanoic acid and 3,5,5-trimethylhexylcarboxylic acid and "other various esters, acetal, etc." However, "other various esters" have not been determined, although it is speculated that they are also formate esters, possibly derived from, for example, an alcohol that is isomerized to the desired 3,5,5-trimethylhexanol. No specific ester component is mentioned for the specific composition given for the crude and semi-refined aldehyde fractions, and it is concluded that the ester content of any one of the compositions must be minimal. Furthermore, it is taught that the copper-zinc oxide catalyst has a longer life when using a purified aldehyde. This concludes that one or more minor components of the crude or semi-refined aldehyde fraction may be one of 3,5,5-trimethylhexylformate or "a variety of other esters" Acts as a catalyst poison or deactivator. As taught in Example 1, the hydrogenation of the refined aldehyde fraction contains, in addition to 3,5,5-trimethylhexanal, from 1% to 3% of 3,5,5-trimethylhexanoic acid, wherein the catalyst life exceeds There was no loss of catalyst activity for 300 hours, and it appears that 3,5,5-trimethylhexanoic acid is not a substance that causes poisoning or inactivation of the catalyst. Among the other materials mentioned as components of the crude or semi-refined aldehyde fraction, acetaldehyde (unstable adduct of aldehydes and alcohols) seems unlikely to be a compound which causes a decrease in catalyst activity. Thus, one skilled in the art can infer that the ester component of the crude or semi-refined fraction is the chief culprit in shortening the life of the catalyst. Hydrogenolysis of esters is described in U.S. Patent No. 2,794,414. It teaches the use of copper catalysts which can be promoted with oxide promoters such as manganese oxide, zinc oxide, magnesium oxide or chromium oxide. In one embodiment, n-butyl butyrate is converted to n-butanol using a mixture of copper oxide, zinc oxide and magnesium oxide in an 8:1:1 weight ratio, wherein the ester conversion is about 50%. The hydrogen ester molecular ratio was about 10:1 at a temperature of 322 ° C and a pressure of 2680 lbs. Per square inch (about 189.4 kg / cm 2 ). It is taught that the optimum conversion to alcohol can be obtained at the highest pressures available in the equipment available and at the lowest temperatures consistent with the actual reaction rates obtained. Although the operation in the "vapor phase" is mentioned, it is apparent that it is intended to operate at temperatures above the critical temperature of the ester. This is confirmed by the teaching that, when operating in the gas phase, it is preferred to use the temperature at room temperature.

 

Angenechem offers numbers of Aldehydes: 

939757-47-8	939758-80-2	939758-81-3
939759-36-1	939759-12-3	939760-42-6
939760-83-5	939761-36-1	939761-35-0
939761-80-5	939807-27-9	939807-28-0
939807-75-7	939807-79-1	939819-21-3
93982-60-6	939973-20-3	939986-34-2
939999-37-8	939999-58-3	939999-41-4
939999-67-4	94019-86-0	940215-81-6
94053-73-3	940616-19-3	940639-22-5
940865-87-2	940879-48-1	940881-63-0
940927-35-5	940959-16-0	941119-19-3
94155-78-9	941319-37-5	94128-94-6
941472-59-9	941571-79-5	941667-77-2
941685-08-1	941669-94-9	941686-18-6
941706-66-7	941710-21-0	941710-22-1