JPH0436259A - Production of alkylketene dimer - Google Patents

Abstract

PURPOSE:To obtain the subject compound having high purity in high yield by reacting an aliphatic acid chloride a with lower tertiary amine, adding hydrochloric acid to the resultant reaction mixture by dividing two times, respectively adjusting to a specific pH and separating the aqueous solution of the lower tertiary amine hydrochloric acid salt. CONSTITUTION:Aliphatic acid chloride is made to react with a lower tertiary amine to obtain the corresponding alkyl ketene dimer. In said process, hydrochloric acid is added to the resultant reaction mixture and pH of the mixture is adjusted to 5-7 to divide into two layers. Then, hydrochloric acid is further added to adjust pH at <=2, thus the resultant mixture is further divided into two layers, and an aqueous solution of the lower tertiary amine salt is separated to afford the highly purified alkyl ketene dimer in high yield. By said method, the alkylketene dimer can be obtained without any special equipment nor special additive. Production of alkylketene dimer having >=36C is also industrially possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing highly pure alkyl ketene dimer with good yield.

[Prior Art] Long-chain alkyl ketene dimers (hereinafter simply referred to as alkyl ketene dimers) are produced by the dimerization reaction of alkyl ketenes generated in the dehydrochlorination reaction of fatty acid chlorides with tertiary amines (Japanese Patent Publication No. 1983-1999). 13620). Specifically, a fatty acid chloride is dissolved in an inert solvent such as benzene, and a lower tertiary amine is added dropwise to cause a reaction, thereby trimerizing the ketene produced. Thereafter, unreacted lower tertiary amines are treated with hydrochloric acid to remove them as a lower tertiary amine hydrochloride aqueous solution having a pH of 5 to 6.5, and then the solvent of the inert solvent solution of the alkyl ketene dimer is removed under reduced pressure to form alkyl ketene dimers. A common method is to produce dimers.

[Problems to be Solved by the Invention] In the above method for producing an alkyl ketene dimer, when the alkyl ketene dimer solution and the lower tertiary amine hydrochloride aqueous solution in the reaction mixture are separated, free lower tertiary ketene dimer is added to the alkyl ketene dimer solution. The triamine remains. Therefore, there was a problem that the purity of the alkyl ketene dimer obtained by removing the solvent of the alkyl ketene dimer solution under reduced pressure was low.

In order to solve the above problem, if the unreacted lower tertiary amine is treated with hydrochloric acid and the pH is adjusted to <2, no free lower tertiary amine remains, but the alkyl ketene dimer solution and the lower tertiary amine hydrochloric acid There was a problem in that emulsification with the salt aqueous solution occurred and the yield of alkyl ketene dimer decreased.

An object of the present invention is to provide a method for producing an alkyl ketene dimer that can obtain a highly pure alkyl ketene dimer in high yield.

[Means for Solving the Problem] As a result of analyzing the conditions for separating an alkyl ketene dimer solution and a lower tertiary amine hydrochloride aqueous solution after alkyl ketene dimer synthesis, the present inventors found that the alkyl ketene dimer solution and lower The present invention was completed based on the discovery that the separability from the tertiary amine hydrochloride aqueous solution depends on the pH adjustment method of the reaction mixture.

That is, the present invention synthesizes a corresponding alkyl ketene dimer by reacting a fatty acid chloride with a lower tertiary amine, adjusts the reaction mixture to pH 5 to 7 with hydrochloric acid, separates the reaction mixture into two layers, and then further reacts with hydrochloric acid. This is a method for producing an alkyl ketene dimer, which is characterized in that the reaction mixture is separated into two layers by adjusting the pH to <2, and then the lower tertiary amine hydrochloride aqueous solution is separated.

The fatty acid chloride that can be used in the present invention is not particularly limited as long as it has at least one hydrogen atom on the carbon adjacent to the carbonyl group. Specifically, saturated carboxylic acids include caproic acid, caprylic acid, capric acid,
Unsaturated carboxylic acids such as lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, and behenic acid include fatty acid chlorides derived from oleic acid, linoleic acid, linuric acid, etc., and fatty acid chlorides derived from mixtures thereof. It will be done.

The lower tertiary amine that can be used in the present invention has a dissociation constant of 9.
There is no particular limitation as long as it is above. Specific examples include triethylamine and tripropylamine, but triethylamine is most preferred from the viewpoint of handling and economical advantages.

The amount of lower tertiary amine used in the present invention is most preferably 1.03 to 1.20 times the mole of chlorine in the fatty acid chloride. If the amount is less than 1.03 times the mole, the reaction will not be completely completed, and if it exceeds 1.20 times the mole, it is not only economically disadvantageous, but also by-products such as alkyl ketene trimers and tetramers will increase.

The solvent that can be used in the present invention needs to be an inert solvent that dissolves at least the fatty acid chloride, lower tertiary amine, and alkyl ketene dimer, and does not induce hydrolysis of the alkyl ketene dimer. Specifically, lower ethers, hexane, cyclohexane, benzene,
Examples include toluene, chloroform, and carbon tetrachloride. These may be dehydrated in advance using various dehydrating agents, or they may be commercially available products as they are.

The concentration of hydrochloric acid that can be used in the present invention is not particularly limited as long as it dissolves the lower tertiary amine hydrochloride in the reaction mixture.

The temperature during pH adjustment according to the present invention is preferably 60° C. or lower, and a temperature higher than that induces hydrolysis of the alkyl ketene dimer.

The manufacturing method of the present invention is carried out, for example, as follows.

In the following, percentages represent weight % unless otherwise specified.

After the fatty acid chloride and the solvent are charged into a reaction vessel equipped with a stirrer, a thermometer, and a dropping device, an inert gas such as nitrogen or helium is introduced while stirring the contents. Next, a lower tertiary amine was added dropwise while maintaining the inside of the system at 20 to 60°C, and the temperature was kept at 20 to 60°C for 3 hours from the time the dropping was completed.
The reaction is matured. Thereafter, hydrochloric acid was added dropwise to adjust the reaction mixture to pH 5 to 7, and the reaction mixture was left to stand at 30 to 60'C to separate into two layers. Hydrochloric acid was further added dropwise with stirring until the reaction mixture reached a pH < 2. Stop dripping at this point. After completion of the dropwise addition, the reaction mixture is allowed to stand at 3°C to 60°C to separate into two layers, and then the lower tertiary amine hydrochloride aqueous solution is removed.

If the initial pH is greater than 7, the solution will not separate into two layers, an alkyl ketene dimer solution and a lower tertiary amine aqueous solution, even if the pH is then adjusted to <2. It is difficult to adjust the pH to 2 or more and less than 5 because this is near the neutralization equivalent point of lower tertiary amine and hydrochloric acid. Further, even if the pH is set to <2 from the beginning, the solution does not separate into two layers: the alkyl ketene dimer solution and the lower tertiary amine aqueous solution.

Target alkyl ketene dimer Tendimer obtained by.

[Effects of the Invention] According to the present invention, a highly pure and high quality alkyl ketene dimer can be obtained in high yield without using special equipment or special additives for the reaction.

That is, regardless of the type of fatty acid chloride.

The alkyl ketene dimer obtained has a purity of 90% or more, and the yield is 98% or more of the theoretical value.

Furthermore, even in the production of alkyl ketene dimers with carbon numbers exceeding 36, which have traditionally been difficult to produce industrially, emulsification is possible in the separation process of the alkyl ketene dimer solution and lower tertiary amine hydrochloride aqueous solution after the reaction. It doesn't happen at all.

[Examples] The present invention will be explained with reference to Examples and Comparative Examples. The purity of the alkyl ketene dimer can be measured according to "Oil Chemistry, 8, 2.
79 (1959) J.

Example 1 250 g of stearic acid chloride and 700 g of benzene were charged into a 2-liter four-bottle flask equipped with a stirrer, a thermometer, a dropping funnel, and a gas introduction tube. Nitrogen gas was introduced at a rate of 20 ml/min, and the mixture was stirred. It was kept at 30°C.

Next, 95 g of triethylamine (1.15 times the mole relative to the chlorine of stearic acid chloride) was added dropwise over 3 hours and the reaction was carried out at 30'C. After the dropwise addition, the temperature was raised to 50°C and the reaction was continued for 2 hours. It was matured.

After the reaction was completed, 2% hydrochloric acid was added until the pH of the reaction mixture reached 5.5, and the mixture was left standing at 50° C. until the reaction mixture separated into two layers (0.5 hours). Next, while stirring the reaction mixture, 2% hydrochloric acid was added until the pH reached 1.5, and then
The reaction mixture was allowed to stand at 0.degree. C. until the reaction mixture separated into two layers (1.5 hours). The state of separation between the alkyl ketene dimer solution and the lower tertiary amine hydrochloride aqueous solution was good.

Next, the lower tertiary amine hydrochloride aqueous solution was separated to obtain a benzene solution of the alkyl ketene dimer.

This benzene solution was concentrated at 40° C. under reduced pressure to obtain an alkyl ketene dimer.

The purity of the alkyl ketene dimer obtained was 94.

The yield was 99.1% at 4%.

Example 2 250 g of behenoyl chloride and 700 g of benzene were charged into the same apparatus as in Example 1, and nitrogen gas was introduced at 20 m
l/min and kept at 30°C with stirring.

Next, 80 g of triethylamine (1.15 times the mole relative to the chlorine of behenoyl chloride) was added dropwise over 3 hours to carry out the reaction at 30°C, and after the dropwise addition was completed, the temperature was raised to 50"C.
The reaction was aged for 2 hours.

After the reaction was completed, 2% hydrochloric acid was added until the pH of the reaction mixture reached 5.4, and the mixture was left standing at 50° C. until the reaction mixture separated into two layers (0.5 hours). Next, while stirring the reaction mixture, 2% hydrochloric acid was added until the pH reached 1.5, and then 50
The reaction mixture was allowed to stand at 0.degree. C. until the reaction mixture separated into two layers (1.0 hour). The state of separation between the alkyl ketene dimer solution and the lower tertiary amine hydrochloride aqueous solution was good.

Next, the lower tertiary amine hydrochloride aqueous solution was separated to obtain a benzene solution of the alkyl ketene dimer.

This benzene solution was concentrated at 40° C. under reduced pressure to obtain an alkyl ketene dimer.

The purity of the obtained alkyl ketene dimer was 93.

The yield was 98.7% at 6%.

Example 3 250 g of behenoyl chloride and 700 g of benzene were charged into the same apparatus as in Example 1, and nitrogen gas was introduced at 20 m
l/min and kept at 30°C with stirring.

Next, 83 g of triethylamine (1.20 times the mole relative to the chlorine of behenoyl chloride) was added dropwise over 3 hours to carry out a reaction at 30°C. After the dropwise addition, the temperature was raised to 50°C, and 2
Time reaction aging was performed.

After the reaction was completed, 2% hydrochloric acid was added until the pH of the reaction mixture reached 6.0, and the mixture was left standing at 50° C. until the reaction mixture separated into two layers (0.5 hours). Next, while stirring the reaction mixture, 2% hydrochloric acid was added until the pH reached 1.4, and then 50
The reaction mixture was allowed to stand at 0.degree. C. until the reaction mixture separated into two layers (1.0 hours). The state of separation between the alkyl ketene dimer solution and the lower tertiary amine hydrochloride aqueous solution was good.

Next, the lower tertiary amine hydrochloride aqueous solution was separated to obtain a benzene solution of the alkyl ketene dimer.

This benzene solution was concentrated at 40° C. under reduced pressure to obtain an alkyl ketene dimer.

The purity of the alkyl ketene dimer obtained was 98.8%, and the yield was 94.0%.

The manufacturing conditions and results of Examples 1 to 3 are summarized in Table 1. As is clear from Table 1, the separation state of the reaction mixture was good, the purity of the obtained alkyl ketene dimers was 90% or more, and the yield was 98% of the theoretical value.
% or more.

Comparative Example 1 Stearic acid chloride 300 was added to the same apparatus as in Example 1.
and 700g of benzene, and 20ml of nitrogen gas.
/min and maintained at 30° C. with stirring.

Next, 114 g of triethylamine (1.15 times the mole relative to the chlorine of stearic acid chloride) was added dropwise over 3 hours to carry out the reaction at 30°C. After the dropwise addition, the temperature was raised to 50°C and the reaction was aged for 2 hours. went.

After the reaction was completed, 2% hydrochloric acid was added until the pH of the reaction mixture became 1.6, and then the reaction mixture was allowed to stand at 50°C. Even after one hour, the reaction mixture was only separated into two layers: an organic layer of alkyl ketene dimer solution and an emulsified layer consisting of lower tertiary amine hydrochloride and some alkyl ketene dimer.

Next, the lower tertiary amine hydrochloride aqueous solution containing the emulsified layer was separated to obtain a benzene solution of the alkyl ketene dimer.

This benzene solution was concentrated at 40° C. under reduced pressure to obtain an alkyl ketene dimer.

The purity of the alkyl ketene dimer obtained was 93.1%, and the yield was 9Q, 1%.

Comparative Example 2 250 g of behenic acid chloride and 700 g of benzene were charged into the same apparatus as in Example 1, and nitrogen gas was introduced at 20 m1/m.
The mixture was introduced at 30° C. and maintained at 30° C. with stirring.

Next, 80 g of triethylamine (1.15 times the mole relative to the chlorine of behenoyl chloride) was added dropwise over 3 hours to carry out the reaction at 30°C, and after the completion of the dropwise addition, the temperature was raised to 50°C and 2
Time reaction aging was performed.

After the reaction was completed, 2% hydrochloric acid was added until the pH of the reaction mixture reached 1.5, and then the reaction mixture was allowed to stand at 50°C. Even after one hour, the reaction mixture was only separated into two layers: an organic layer of alkyl ketene dimer solution and an emulsified layer consisting of lower tertiary amine hydrochloride and some alkyl ketene dimer.

Next, the lower tertiary amine hydrochloride aqueous solution containing the emulsified layer was separated to obtain a benzene solution of the alkyl ketene dimer.

This benzene solution was concentrated under reduced pressure at 40''C to obtain an alkyl ketene dimer.

The purity of the alkyl ketene dimer obtained was 90.5%, and the yield was 88.5%.

Comparative Example 3 250 g of behenic acid chloride and 700 g of benzene were charged into the same apparatus as in Example 1, and nitrogen gas was introduced at 20 m1/m.
The mixture was introduced at 30° C. and maintained at 30° C. with stirring.

Next, 83 g of triethylamine (1.20 times the mole relative to behenic acid chloride) was added dropwise over 3 hours.
The reaction was carried out at .degree. C., and after the dropwise addition was completed, the temperature was raised to 50.degree. C., and the reaction was aged for 2 hours.

After the reaction was completed, 2% hydrochloric acid was added until the pH of the reaction mixture became 1.0, and then the reaction mixture was allowed to stand at 50°C. Even after one hour, the reaction mixture was only separated into two layers: an organic layer of alkyl ketene dimer solution and an emulsified layer consisting of lower tertiary amine hydrochloride and some alkyl ketene dimer.

Next, the emulsified layer containing the lower tertiary amine hydrochloride was separated to obtain a benzene solution of the alkyl ketene dimer. This benzene solution was concentrated at 40° C. under reduced pressure to obtain an alkyl ketene dimer.

The purity of the alkyl ketene dimer obtained was 91.1%, and the yield was 88.0%.

The manufacturing conditions and results of Comparative Examples 1 to 3 are summarized in Table 1.

As is clear from Table 1, the yields of the alkyl ketene dimers obtained are lower than those of the Examples. That is,
In the comparative example, significant emulsification of the alkyl ketene dimer solution and lower tertiary amine hydrochloride aqueous solution occurs, resulting in a decrease in the purity and yield of the alkyl ketene dimer.

Patent applicant: NOF Corporation

Claims (1)

[Claims] The corresponding alkyl ketene dimer was synthesized by reacting a fatty acid chloride with a lower tertiary amine, the reaction mixture was adjusted to pH 5 to 7 with hydrochloric acid, the reaction mixture was separated into two layers, and then the pH was adjusted to <2 with hydrochloric acid. A method for producing an alkyl ketene dimer, which comprises adjusting the reaction mixture to separate into two layers, and then separating a lower tertiary amine hydrochloride aqueous solution.