申请人:Bayer Aktiengesellschaft
公开号:US04791229A1
公开(公告)日:1988-12-13
A process for the preparation of an aryl cyanamide comprising reacting an arylamine of the formula ##STR1## in which Ar is aryl, R is hydrogen or alkyl, and n is 1, 2 or 3, (excepting 2-nitroaniline, 4-nitroaniline and arylamines having a nucleophilic character equal to or lower than 2-nitroaniline and 4-nitroaniline), with cyanogen chloride in 1-2 times the molar amount per mole of amino group of the arylamine initially in a homogeneous liquid phase using as reaction medium acetic acid (which is optionally diluted with water and/or a water-miscible, organic auxiliary solvent) in the presence of 1-1.5 molar equivalents of an auxiliary base for each amino group of the arylamine, there being more cyanogen chloride than equivalents of auxiliary base present in the reaction mixture at any point in time of the reaction, the pH of the reaction mixture being maintained below 7.
一种制备芳基氰胺的方法,包括将具有以下结构的芳基胺进行反应:其中Ar为芳基,R为氢或烷基,n为1、2或3(不包括2-硝基苯胺、4-硝基苯胺和具有与2-硝基苯胺和4-硝基苯胺相等或更低亲核性的芳基胺),与氯化氰在1-2倍于芳基胺氨基的摩尔量中以均相液相的形式在反应介质乙酸中反应(可选地与水和/或水溶性有机辅助溶剂稀释),在每个芳基胺氨基的情况下,存在1-1.5摩尔当量的辅助碱,反应混合物中氰化氰的量始终多于反应过程中的辅助碱当量,反应混合物的pH值保持在7以下。