Process for the preparation of aromatic mercapto compounds

• Main Authors: HAHN WILLI, GOLIASCH KARL
• Format: Patent
• Language: English
• Published: 27.09.1966

Aromatic mercapto compounds are made by reacting a phenol or a phenol ether, which contains at least one hydrogen atom in ortho or para position to the -OH group or ether group, with a sulphur chloride and hydrogen sulphide at a temperature in the range of from -50 DEG C. and + 200 DEG C., recovering the poly-sulphide formed and reducing the polysulphide to the mercaptan. The phenols used are mono or polyhydroxy phenols of mono- or poly-nuclear aromatic systems in which the hydroxy groups may be etherified partly or entirely with aliphatic or aromatic radicals. They can be substituted by alkyl or aryl radicals or by halogen, mercapto- and alkyl(aryl)-mercapto groups. Suitable examples are given. The process may be effected with or without solvents. A Lewis acid or proton acid may be used as a catalyst, particularly FeCl3,AlCl3, ZnCl2, SnCl3, BF3, H2SO4 and H3PO4. The polysulphide may be reduced to the mercaptan by reaction with nascent or catalytically activated hydrogen, with hydrogen sulphide and its alkali metal salts, with grape sugar and with alkali metals or alkali metal amalgams. Examples describe the preparation of o- and p-mercapto-m-cresol and dicresol sulphide; 4-mercapto-anisole; 6-mercapto - 3 - methoxy - 1 - methylbenzene; 4-mercapto - 1,2 - dimethoxybenzene; 4 - mercaptophenol; 4-mercapto-2-chlorophenol; 4-mercapto - 2 - sec. butyl - phenol; 4 - mercapto - 2,6 - di - tert. butyl phenol; 2 - methoxy - 5 - mercapto - 1 - methylbenzene; 6-mercapto - 3 - methoxy - 1 - methyl - benzene; 4 - mercapto - 1 - ethoxybenzene; 2 - methoxy- 5 - mercapto - 1 : 3 - diisopropyl - benzene; 5-methoxy - 2 - mercapto - 1 : 3 - dimethylbenzene; 4 - mercapto - and 1 - isopropoxybenzene. Specifications 577,013 and 635,129 are referred to.