DE722464C - Process for the preparation of aliphatic saturated chlorine- or bromine-substituted monocarboxylic acid esters - Google Patents

Description

Process for the preparation of aliphatic saturated chlorine or Bromine-substituted monocarboxylic acid esters - a generally applicable process, that the production of halogen fatty acids or their esters in a simple manner and Permitted with good yields has not yet become known. Only the a-position bromine-substituted fatty acids are according to the classical method Easily accessible from H e 11-V o 1 h a r d - Z e 1 i n s ky. In, B or 7 position or halogen fatty acids substituted at an even greater distance from the carboxyl group are, however, very difficult to access, apart from special cases.

It has been found that aliphatic saturated chlorine or bromine-substituted monocarboxylic acid esters with different positions of the halogen can easily be produced by the action of chlorine or bromine on salts of acidic esters of saturated aliphatic dicarboxylic acids with metals of the first, second or third group of the periodic table of elements permit. The carboxyl group bound to the metal is split off as carbon dioxide and the metal as the metal halide, according to the following equation Me00C-R-COOR '+ Hlg2>Hlg-R-COOR' + C02 + MeHlg Here R is a divalent, saturated aliphatic hydrocarbon radical, if one disregards half-esters of oxalic acid in which R = O. R 'is the radical of the alcoholic component of the ester; Hlg means chlorine or bromine.

So you get z. B. from the silver salt of Adipinäthyl- or Adipinmethylesteräure the methyl oi-bromopentanoate or ethyl co-bromopentanoate in good yield. Any other esters can also be used in place of the methyl or ethyl esters.

The reaction is best carried out using an inert diluent, such as carbon tetrachloride, chloroform, ether or air. But you can also work with the pure substances, if one takes care that the dry ones are Do not overheat salts when exposed to chlorine or bromine, otherwise the reaction products continue to react with the still unchanged salts or else with excess halogen, more highly halogenated esters are formed.

The following examples illustrate the process of the invention. EXAMPLE II 76o g of the silver salt of adipic methyl ester acid are slurried in 21 dry carbon tetrachloride and, with occasional cooling and shaking, dry bromine (about 330 cc) is gradually added. When enough bromine has been added, which can be recognized by the pure yellow color of the silver brolriid which is precipitating, it is warmed to a gentle boil on the water bath for a while. The silver bromide is then filtered off, the silver bromide is well-washed with carbon tetrachloride, the carbon tetrachloride is distilled off, the residue is expediently taken up in any solvent and mixed with solid potassium carbonate or. but shaken out an aqueous bicarbonate solution to remove the acidic constituents. After the solvent has been driven off, the resulting methyl 5-bromopentanoate is distilled in a water-jet vacuum.

Bp "= 96 to 104 °, yield 881 g = 68.50 / 0 of theory.

EXAMPLE 2 A slurry of 4973 g of silver salt d-es-hexadecanedioic acid 1 # 16 monomethyl ester is treated with bromine in a manner similar to that described in Example 1. When the reaction is complete, the mixture is worked up in the same way as previously described and, after removal of the acidic constituents, the methyl 15-bromopentadecanoate is distilled in a high vacuum.

KP; [= 180 °, yield 3505 g = 85.5% of theory.

By saponification, 15-bromopentadecanoic acid is obtained as a pearlescent one Leaflets. F. = 66 °.

In a similar way, numerous other brominated or chlorinated esters and the corresponding acids could be prepared with consistently excellent yields, 7.B. Brinylacetic acid ethyl ester, b.p. 5 = 65 °, from this bromoacetic acid M.p. = 48 to 50 °, b.p. = 115 to 118 ', a-ethyl bromobutyrate bp, 8 = 75 to 78 ° (from ethylmalonic acid # monomethyl ester salts), I o-bromodecanoic acid methyl ester 1, #' - p ,, = 164 to 166 °, from this the io-bromodecanoic acid bp2 = 155 to 65 °, 12-bromododecanoic acid methyl ester Bp8 = 175 °, from this the 12-bromododecanoic acid F. = 5o, to 5o, 5 °, 1q.-bromotetradecanoic acid methyl ester bp "q = 162 to 168 °, from this the 1 q.-bromotetradecanoic acid F. . = 6 [to 66 °, 16-B.romhexadecanoic acid methyl ester, melting point = 23.5 °, 17-bromoheptadecanoic acid methyl ester, b.p.

The products of the process can be used for numerous syntheses, z. B. in the fragrance industry.

Claims (2)

PATENT CLAIMS: 1. Process for the preparation of aliphatic saturated chlorine- or bromine-substituted monocarboxylic acid esters, characterized in that salts of acidic esters of aliphatic saturated dicarboxylic acids with metals of the first, second or third group of the periodic table of the elements chlorine or bromine, if necessary with cooling , can act. 2. The method according to claim I, characterized in that the salts of the ester acids in the presence of indifferent Solvents or diluents, such as carbon tetrachloride, chloroform, ether or Air treated with chlorine or bromine.