JPS5929182B2 - Manufacturing method of adipic acid diester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing an adipic acid diester by hydroesterifying a 3-pentenoic acid ester.

Conventionally, as a method for producing adipic acid diester by reacting 3-pentenoic acid ester, carbon monoxide, and alcohol, a method is known in which the reaction is carried out in a homogeneous system using cobalt carbonyl as a catalyst in the presence of a tertiary amine. .

However, when such existing methods are implemented industrially, complicated steps are required to recover the catalyst.

That is, the catalyst containing cobalt carbonyl is unstable and cannot be recovered in a form that maintains its activity. Therefore, it is necessary to recover the cobalt component from the reaction product solution as an inorganic or organic acid salt and then re-prepare the cobalt carbonyl, which increases the cost of catalyst recovery and is by no means a satisfactory method. As a result of extensive research in order to avoid the above-mentioned disadvantages, the present inventor has conducted a hydroesterification reaction of 3-pentenoate ester in a heterogeneous system using insoluble cobalt sulfide as a catalyst, unlike the conventionally used soluble cobalt carbonyl. The present invention was completed based on the discovery that if carried out, the catalyst could be easily recovered and adipic acid diester could be produced with high selectivity.

As the 3-pentenoic acid ester in the present invention, lower alkyl esters of 3-pentenoic acid such as methyl ester, ethyl ester, propyl ester, and butyl ester are preferable, and among these, methyl ester can be optionally selected by exchange reaction with other alcohols. It is particularly useful as it is used to make esters of The alcohol used in the present invention is preferably a lower alcohol such as methanol, ethanol, propanol, butanol, etc. The same alcohol as the alcohol source of the raw material 3-pentenoic acid ester may be used, or a different alcohol may be used depending on the purpose. It is okay to use.

The amount of alcohol used is at least equimolar to the 3-pentenoic acid ester, preferably in the range of 1 to 5 moles. Below this range, the proportion of unreacted 3-pentenoic acid ester increases and the space-time yield of adipic acid diester decreases. Further, if the content is above this range, the hydroesterification reaction rate of 3-pentenoic acid esters becomes slow, and the above range is practical. The tertiary amines used in the present invention include pyridine, picolines, lutidines, quinolines, and isoquinolines, and two or more of these may be used in combination.

Examples of these are pyridine, α-picoline, β-vicoline, r-picoline, 2,3-lutidine, 2,4-lutidine, 2,5-lutidine, 2,6-lutidine, 3,4-lutidine, 3,5-lutidine. -lutidine, 4-benzylpyridine, 4-
Examples include vinylpyridine, quinoline, isoquinoline and the like. The amount of tertiary amine is 0.05 to 1.0 mol, preferably 0.1 to 0.0 mol, per 1 mol of 3-pentenoic acid ester.
The amount is 5 mol, and although the reaction proceeds outside this range, the reaction rate becomes slow.

The cobalt sulfide used as a catalyst in the present invention may be any cobalt compound containing sulfur, such as cobalt sulfide 89, cobalt sulfide, cobalt 72 sulfide, cobalt 4 trisulfide, and the like. Cobalt sulfide can be used as a powder and dispersed in the reaction system, or it can be molded into an appropriate size and used as a packed layer. It can also be used in a state where it is supported on a carrier such as activated carbon, silica, alumina, diatomaceous earth, or zeolite. The amount of cobalt sulfide used in the present invention cannot be generally defined depending on the form of use, but it is from 10 to 500 milliatoms, preferably from 20 to 20 milliatoms as metallic cobalt per mole of 3-pentenoic acid ester.
This is the amount containing 0 milliatoms.

If the amount is less than this, the reaction will proceed, but the reaction rate will be slow, and if it is more than this range, there will be no adverse effect on the reaction, but the above range is practically sufficient. In the present invention, the following solvents can be used in combination with the tertiary amine.

For example, hydrocarbons include hexane, octane, cyclohexane, benzene, toluene, and the like, and oxygen-containing compounds include ether, tetrahydrofuran, dioxane, methyl acetate, and the like. The amount of solvent used is from 0 to 20 moles per mole of 3-pentenoic acid ester.

Even if it is more than this, there is no problem with the reaction, but it is not economical. The reaction temperature in the present invention is in the range of 150 to 220°C, preferably 160 to 200°C. Although the reaction proceeds at lower temperatures, the reaction rate is slow, and at higher temperatures side reactions tend to occur, which is not preferable. The carbon oxide partial pressure in the present invention is 50 kg/i or more, and although there is no particular restriction on the upper limit, it is practically 100 to 4001
A range of <g/CiA is preferable.

If the method of the present invention is carried out while satisfying these conditions, the amount of by-products can be reduced and adipic acid diester can be obtained from 3-pentenoic acid ester with high selectivity, and the catalyst used can be a simple A-filtering operation. It can be separated, recovered and reused, making it possible to industrially advantageously produce adipic acid diester.
The method of the present invention can be carried out either batchwise or continuously.

In addition, in the case of a continuous type, if a method is adopted in which the catalyst is retained in the reaction system or in a packed bed, the catalyst recovery operation becomes unnecessary. Example 1 Methyl 3-pentenoate 10% was placed in a stainless steel shaking autoclave with an internal volume of 100 m1. (0.0876 mol), methanol 3.5r (0.1092 mol), pyridine 11 (0.126 mol) and cobalt sulfide powder 17, and carbon monoxide 200 kg/Cr! The reaction was carried out at 185° C. for 3 hours under pressure.

As a result, the reaction rate of methyl 3-pentenoate was 95 mol%, and the selectivity to dimethyl adipate was 70.5 mol%.
It was hot.

Others dimethyl 2-ethylsuccinate 2.2 mol%, 2
-8.3 mol% of dimethyl methylglutarate and 8.9 mol% of methyl n-monovalerate were produced as by-products. Example 2 A reaction was carried out under exactly the same conditions as in Example 1, except that the catalyst used in Example 1 was separated by filtration and reused as it was.

As a result, the reaction rate of methyl 3-pentenoate was 94.6 mol%, and the selectivity to dimethyl adipate was 70.7 mol%.

Others dimethyl 2-ethylsuccinate 2.3 mol%, 2
8.0 mol% of dimethyl -methylglutarate and 8.2 mol% of dimethyl n-monovalerate were produced as by-products. Example 3 Methyl 3-pentenoate 10r (0.0876 mol), methanol 3.57 (0.1092 mol), r-picoline 57 (0.0537 mol), hexane 10f (0.11 mol)
60 mol) and 1 t (0.01 mol) of cobaltous sulfide powder (0.01 mol)
1 mol) and reacted under the same conditions as in Example 1.

As a result, the reaction rate of methyl 3-pentenoate was 93.0 mol%, and the selectivity to dimethyl adipate was 72.2 mol%.

Claims (1)

[Claims] 1. A method for producing an adipic acid diester, which comprises reacting a 3-pentenoic acid ester, carbon monoxide, and an alcohol in the presence of a tertiary amine using cobalt sulfide as a catalyst.