| 摘要 |
Salts of thioether dicarboxylic acids are obtained by heating lactones with alkali metal or alkaline earth metal sulphides or hydrosulphides to 150-300 DEG C. in the presence of an inert organic diluent boiling in the said temperature range and in which the said sulphides and hydrosulphides are insoluble. If the sulphides or hydrosulphides used contain water they are first mixed with the diluent and the mixture is then heated until the water has distilled off before the lactone is added. Specified lactones are gamma-butyrolactone, gamma- or delta-valerolactone, beta-propiolactone, angelic lactone, and the lactone of benzyl alcohol orthocarboxylic acid. Suitable organic siluents are tetrahydronaphthalene, diethylbenzene, triethylbenzene and mixtures thereof. When commercial hydrated sodium sulphide (Na2 S.9H2O) is used the reaction may be carried out by covering the sulphide with tetrahydronaphthalene and heating to boiling so as to distil off the water of crystallization. The lactone can then be allowed to flow in gradually while water of crystallization is still being split off but it is preferred to heat the mixture until the water of crystallization has been completely distilled off before the lactone is added. A similar procedure may be followed when using sodium hydrosulphide instead of hydrated sodium sulphide. The free dicarboxylic acids may be obtained from the salts by acidification. In examples: (1) a suspension of commercial sodium sulphide containing 98 per cent Na2S, 1 per cent H2O and 1 per cent NaOH in tetrahydronaphthalene is boiled under reflux and gamma-butyrolactone allowed to flow in. After boiling and allowing to cool the precipitate formed is filtered off, dried, and acidified with hydrochloric acid to yield thiodipropyl ether gamma, gamma1-dicarboxylic acid; (2) hydrated sodium sulphide (Na2S.9H2O) is introduced into a mixture of tri- and polyethyl benzenes and after boiling to remove water gamma-butyro lactone is added while the mixture is still boiling. After further boiling the mixture is cooled and water is added and the aqueous layer formed is separated from the non-aqueous layer, filtered, and acidified with hydrochloric acid to yield the same product as in (1); (3) and (4) the same product is obtained by reacting commercial sodium hydrosulphide and commercial sodium hydrosulphide dihydrate respectively with gamma-butyrolactone, the diluents being tetrahydronaphthalene and a polyethyl benzene mixture as used in (2) respectively. Specification 639,679 is referred to. |
