GB475296A - Improvements in process for manufacture of mercapto aryl thiazoles - Google Patents

Abstract

An increased yield of mercapto-aryl-thiazole is obtained, due to a diminution in the amount of byeproducts formed if in an equilibrium reaction in which byeproducts are formed, the byeproducts are extracted from the crude reaction product and added to succeeding batches of reaction ingredients. The preferred process to which the invention is applied is that in which mercapto-aryl-thiazoles are formed by the interaction of carbon bisulphide, sulphur and a primary aromatic amine. The tars which form the byeproducts are leached out of the reaction product with carbon bisulphide, benzene, toluene, or other hydrocarbon solvent, and added to a succeeding batch. In the process just referred to it is preferred to use carbon bisulphide as the leaching agent since it need not be removed as must a hydrocarbon solvent, but allowed to remain as a constituent of the succeeding batch. The process of the present invention may be applied to both batch processes and continuous processes. The application of the process of the present invention is illustrated by an example in which the byeproducts from the interaction of aniline, sulphur and carbon disulphide were leached out with carbon bisulphide, and added to a second batch. The aniline may be replaced by another primary aromatic amine having a replaceable hydrogen on an ortho carbon atom such as the toluidines and naphthylamines. Specification 283,679, [Class 2 (iii)], is referred to.