JPH04112862A - Production of 3-cyano-3,5,5-trimethylcyclohexanone - Google Patents

Abstract

PURPOSE:To industrially produce the subject compound of a fundamental raw material useful for industry in a good yield at a low cost by reacting isophorone with hydrocyanic acid in the presence of a basic catalyst in a solvent consisting of dimethyl sulfoxide and/or dimethylformamide. CONSTITUTION:In the process for producing 3-cyano-3,5,5-trimethylcyclohexanone from isophorone and hydrocyanic acid at 60-160 deg.C, the reaction is performed in the presence of a basic catalyst by the use of dimethyl sulfoxide and/or dimethylformamide as the solvent. By the process the reaction proceeds in an isophorone/hydrocyanic acid ratio of 1/1 and a high yield can be achieved. The subject compound is useful as a curing agent for epoxy resins and as a starting raw material for higher elastomers and polyurethane coatings.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing 3-cyano-3,5,5-trimethylcyclohexanone (hereinafter abbreviated as IPCN). In detail, the basic catalyst and the solvent dimethyl sulfoxide (hereinafter abbreviated as DMSO) and/or dimethylformamide (hereinafter abbreviated as DMF)
Highly productive IPC from isophorone and hydrocyanic acid in the presence of
The present invention relates to a method for producing N.

IPCN is converted to l-amino-3 through amination and hydrogenation.
1-Isocyanato-3- is derived from -aminomethyl-3,5,5-trimethylcyclohexane and is a curing agent for epoxy resins, high grade elastomers, and a raw material for polyurethane paints.
(Isocyanatomethyl)3.5.5-) An industrially useful basic raw material derived from trimethylcyclohexane,
Demand has been increasing rapidly in recent years.

(Prior Art) A method for producing IPCN using isophorone and hydrocyanic acid as raw materials has been known. For example, W, FJhi tmo
re and C, R, Robert, J, 0. C, 13
, 31 (1948), IPCN was obtained in a yield of about 45% by reacting isophorone and sodium cyanide in a mixed solvent of methanol, water, and glacial acetic acid at room temperature for one week. However, this method has a low yield and requires several days of reaction, so it is not a problem at all as an industrial method.

Furthermore, according to Japanese Patent Publication No. 40-7486, IPCN is continuously synthesized by supplying an isophorone hydrocyanic acid mixture containing about 10% by weight or less of hydrocyanic acid to isophorone on an alkali catalyst attached to a solid carrier. ing. However, this method is problematic as an industrial method because it requires recovery of a large amount of unreacted isophorone.

Further, according to West German Patent No. 1,085,871, IPCN is synthesized by reacting isophorone and hydrocyanic acid in a dimethylacetamide solvent using an alkali metal salt as a catalyst. However, the yield of IPCN by this method is as low as about 70%, and a large amount of expense is required for recovering the solvent.

Furthermore, according to West German Patent No. 1,240.854, rPCN is synthesized by reacting isophorone and hydrocyanic acid in the presence of an alkali metal salt catalyst using methanol as a solvent. However, this method is
According to Publication No. 16038, a large amount of hydrocyanic acid polymer is produced,
[The yield of PCN is as low as about 80%.

Next, according to JP-A-57-116038, in order to avoid the by-product of polymerization of hydrocyanic acid in the presence of an inorganic basic catalyst and glycols, a large excess of isophorone is reacted with hydrocyanic acid to form IPCN. are synthesized. However, it is necessary to recover a large amount of unreacted isophorone, which poses an industrial problem.

Furthermore, according to JP-A-61-33158, IPCN is synthesized by reacting isophorone with hydrocyanic acid in the presence of diaza-bicyclo-alkenes (organic base catalyst). However, this method requires the use of a large amount of expensive catalyst and the recovery of this catalyst, which poses problems for industrial use.

(Problems to be Solved by the Invention) Against this background, a method for industrially producing IPCN from isophorone and hydrocyanic acid with high yield and at low cost is desired.

(Means for Solving the Problem) The present inventors have conducted extensive studies on this method, and found that when the reaction is carried out in the presence of a basic catalyst using DMSO and/or DMF as a solvent, the isophorone/cyanic acid molar ratio It has been discovered that the reaction proceeds with equimolar amounts of 1 and 2, and that IPCN can be obtained in high yield, leading to the present invention.

That is, the method for producing IPCN of the present invention is characterized by reacting isophorone and hydrocyanic acid at a temperature of 60 to 160°C in the presence of a basic catalyst and DMSO and/or DMF.

Examples of the basic catalyst used in the present invention include alkali metals such as sodium and potassium, hydroxides and cyanides of alkali metals such as sodium and potassium,
Known basic catalysts such as carbonates, oxides, and alcolades are used. The amount of the catalyst to be used is not particularly limited, but it is preferably in the range of 0.05 to 1.5% by weight based on the isophorone used.

The amount of the solvent DMSO and/or DMF used is:
Amount and weight of isophorone used in reaction! The ratio is preferably in the range of 5 to 50%. If it is less than 5%, the reaction will be difficult to proceed and it will take a long time to complete the reaction, which is not preferable. Moreover, if it exceeds 50%, the recovery of the solvent will increase, which is not preferable in terms of cost.

The molar ratio of isophorone to hydrocyanic acid used in the reaction is from 0.8 to 1.5, preferably around 1. If it is less than 0.8, a large amount of unreacted hydrocyanic acid remains, resulting in increased post-treatment and increased prussic acid loss. If it exceeds 1.5, the amount of unreacted isophorone increases, which increases the expense for recovery, which is not preferable.

The reaction temperature is 60-160°C, preferably 100-140°C.
It is ℃. Below 60°C, the reaction is slow;
Above this, side reactions increase and the yield decreases.

Although the reaction time is not particularly limited, the target reaction rate can be obtained in 1 to 10 hours.

In carrying out the method of the present invention, fPcN can be produced by heating and stirring a mixture of isophorone, a basic catalyst, and a solvent, and supplying hydrocyanic acid to the mixture to cause the mixture to react.

As a method of supplying hydrocyanic acid, a method of dropping liquid hydrocyanic acid, a method of feeding hydrocyanic acid using an inert gas as a carrier, etc. are used.

(Examples) Hereinafter, the present invention will be specifically explained using Examples, but the present invention is not limited only to these Examples.

As is clear from the examples, when the molar ratio of isophorone/cyanic acid used in the reaction is 1, the yield of IPCN is extremely high, and this has a great effect on industrial implementation.

Example 1 427.7 parts by weight of isophorone, 5.6 parts by weight of potassium carbonate, and 21.3 parts by weight of DMSOI were charged into a reaction apparatus equipped with a stirrer, a cooling tube, a thermometer, and a dropping spout with a cooling tube, and the mixture was heated without stirring. and heated on an oil bath. Prussic acid 8 in the dropping funnel
3.6 parts by weight was added thereto, and while the reaction solution was kept at 110°C, hydrocyanic acid was added dropwise over 3 hours with stirring (isophorone/cyanic acid molar ratio = 1.0). After dropping hydrocyanic acid, reaction was carried out at 110'C for 1 hour, and then 7.1 parts by weight of 80% phosphoric acid was added. Unreacted hydrocyanic acid was removed to less than 0.01% by passing N2 gas. After cooling to room temperature, the salt was filtered off, and the reaction solution was analyzed by gas chromatography.

As a result, the reaction rate of isophorone was 87%, the selectivity to IPCN was 99%, and the yield of IPCN was 86%. In addition, the reaction solution is distilled under reduced pressure to obtain IPC with a purity of 99%.
420 g of N was obtained.

Example 2 Into the same apparatus as in Example 1, 528.3 parts by weight of isophorone, 6.6 parts by weight of potassium carbonate, and 45.5 parts by weight of DMF were charged, and 103.2 parts by weight of hydrocyanic acid was added at a temperature of 110"C while stirring.
Parts by weight were added dropwise over 3 hours to react (isophorone/cyanic acid molar ratio = 1.0). After dropping, heat at 110°C.
After reacting for an hour, 7.1 parts by weight of 80% phosphoric acid was added.

Unreacted hydrocyanic acid was removed to 0.01% or less by passing N2 gas. After cooling to room temperature, the salt was filtered off, and the reaction solution was analyzed by gas chromatography. As a result, the reaction rate of isophorone was 92%, the selectivity to IPCN was 89%, and I
The yield of PCH was 82%. The reaction solution was separated by vacuum distillation to obtain 491 g of IPCN with a purity of 99%.

Comparative Example 1 Into the same apparatus as in Example 1, 528.0 parts by weight of isophorone, 5.1 parts by weight of sodium carbonate, and 37.6 parts by weight of ethylene glycol as a solvent were charged, and 102.0 parts by weight of hydrocyanic acid was added at a temperature of 110°C with stirring. 9 parts by weight was added dropwise over 3.5 hours to react (isophorone/cyanic acid molar ratio = 1.0)
. After completing the dropwise addition, the reaction was carried out at 210″C for 1 hour, and then
9.8 parts by weight of 80% phosphoric acid was added. Unreacted hydrocyanic acid was removed to 0.01% or less by passing N2 gas. After cooling to room temperature, the salts were filtered off and the reaction solution was analyzed. As a result, the reaction rate of isophorone was 47%, and the selectivity to IPCN was 88%.
%, and the yield of IPCN was 41%.

Self + (1 person)

Claims (1)

[Claims] In the presence of a basic catalyst and a solvent, isophorone and hydrocyanic acid are reacted at a temperature of 60 to 160°C to form 3-cyano-3,5,5
- A method for producing 3-cyano-3,5,5-trimethylcyclohexanone, which comprises using dimethyl sulfoxide and/or dimethylformamide as a solvent.