JPH1059899A - Production of aliphatic carboxylic acid tertiary butyl ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an aliphatic carboxylic acid tertiary butyl ester, enabling to obtain the desired t-butyl ester only by mixing methyl tertiary butyl ester with target carboxylic acid. SOLUTION: An aliphatic carboxylic acid of formula I (R is an alkyl, a halogenated alkyl) is reacted with methyl tertiary butyl ether(MTBE) to obtain an aliphatic carboxylic acid tertiary butyl ester of formula II. The MTBE is preferably used in an amount of >=1 mole, preferably several ten-fold moles to several hundred-fold moles, that of the carboxylic acid. The reaction is preferably carried out in a temperature range from room temperature to the refluxing temperature of MTBE. The objective compound can thereby simply be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a t-butyl ester of an aliphatic carboxylic acid.

[0002]

2. Description of the Related Art Conventionally, a carboxyl group of a carboxylic acid is replaced with t.
Method for protecting as -butyl ester 1: Method of reacting with isobutylene in the presence of a Lewis acid [J. Am.
Chem. Soc. , 60 (1938). 657,],
2: Method of reacting with t-butyl alcohol in the presence of a metal oxide [IND. Quimina, 7, (194
5), 393], 3: a method of reacting with t-butyl chloride in the presence of a metal oxide (Tetrahedron,
38, (1982), 12, 1843). However, isobutylene and t-butyl chloride are easily decomposed, and their preparation and handling are difficult.
In addition, since it is necessary to add a metal oxide or a Lewis acid in any of the methods, a separation operation from the product after the reaction is required.

Further, a method of converting carboxylic acid into acid chloride or acid anhydride and then reacting with butyl alcohol (Org. Synth. Coll. Vol III
[1955, 142; Am. Chem. Soc. ,
58, (1936), 1346], but this is not an example of using a carboxylic acid as it is.

[0004] Accordingly, as a result of various studies on protecting agents for protecting as a simple t-butyl ester, MT
It has been found that by using BE, the desired t-butyl ester can be obtained only by mixing with the carboxylic acid of interest.

[0005]

In a method for synthesizing a compound represented by Chemical Formula 2 from a compound represented by Chemical Formula 1 and methyl tertiary butyl ester (hereinafter referred to as MTBE), R in the compound represented by Chemical Formula 1 is an alkyl group ( A chain or branched alkyl group having 1 to 8 carbon atoms and a halogen-substituted alkyl group (a chain or branched alkyl group having 1 to 8 carbon atoms, wherein at least one hydrogen atom is a halogen atom (Cl or Br) )
Alkyl group substituted with a).

[0006]

DETAILED DESCRIPTION OF THE INVENTION The amount of MTBE used is not critical as long as it is at least 1 mol with respect to the carboxylic acid, but it is preferable to use several tens to several hundred mols in order to improve the reaction rate. . There is no problem if the temperature of the protection reaction is not higher than the decomposition point of the carboxylic acid used as a raw material, but the reaction is usually carried out within the range of room temperature or higher to the reflux temperature of MTBE. The purified t-butyl ester can be purified from the reaction mixture by distillation or other methods.

[0007]

【Example】

Example 1 A mixture of acetic acid / MTBE = 1/1 by weight was heated at normal pressure and refluxed for 66 hours. (Liquid temperature 85-88
C), the reaction solution was sampled during the reaction, and the reaction was followed by GC analysis. Table 1 shows the analysis results.

[0008]

[Table 1] Example 2 Instead of the MTBE / acetic acid = 1/1 mixed solution of Example 1, a mixed solution of MTBE / acetic acid = 87/13 (wt ratio) was heated while maintaining the liquid temperature at 57 to 58 ° C. ,
The reaction was performed for 78 hours. The liquid for mixing contained about 5% of water. Table 2 shows the analysis results.

[0009]

[Table 2] Example 3 The same reaction was carried out in Example 1 except that monochloroacetic acid was used instead of acetic acid. As a result, 1-mol% of monochloroacetic acid was formed in the reaction solution based on the amount of charged monochloroacetic acid. .

Example 4 A similar reaction was carried out in Example 1 except that dichloroacetic acid was used instead of acetic acid. In the reaction solution, monochloroacetic acid t-butyl ester was added in an amount of 0 to the amount of charged dichloroacetic acid. 0.5 mol% was produced.

Claims (1)

[Claims] 1. A compound obtained by reacting an aliphatic carboxylic acid shown in Chemical Formula 1 with methyl tertiary butyl ether.
The method for producing an aliphatic carboxylic acid tertiary butyl ester shown in (1). Embedded image Embedded image R: alkyl group halogen-substituted alkyl group