| 摘要 |
1,133,841. Production of phenylhydrazine. BADISCHE ANILIN- & SODA-FABRIK A.G. 18 March, 1966 [20 March, 1965], No. 11918/66. Heading C2C. Phenylhydrazine or salts thereof are obtained by the reduction of phenyl diazonium salts by means of sulphurous acid or salts thereof in aqueous medium wherein the reaction is commenced at from - 5‹ to + 50‹ C. and substantially an alkali or alkaline earth metal hydrogen sulphite (i.e. which may contain sulphurous acid or sulphite) is used as reducing agent in at least a 30 mole per cent stoichiometric excess and the reaction is completed by maintaining the reaction mixture at a higher temperature in the range of from 10‹ to 150‹ C. The sulphite solution preferably does not contain more than 25 mole per cent of free sulphurous acid or 60 mole per cent of sulphite (based on hydrogen sulphite) and the reduction is completed by maintaining the reactive mixture at 10‹ to 150‹ C., optionally with the addition of a mineral acid. The process may be effected batchwise or continuously, in the latter case the sulphur dioxide liberated during the reaction being absorbed, e.g. in caustic soda solution, and the sulphite and hydrogen sulphite solution thus formed may be recycled.
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