发明授权
US5545753A Process for preparing anilines, catalysts used therefor and process for preparing same 失效
制备苯胺的方法,所用的催化剂及其制备方法

Process for preparing anilines, catalysts used therefor and process for
preparing same
摘要:
The process for preparing anilines by reaction of phenols with an amination agent in accordance with the present invention is disclosed, which process is characterized by carrying out the reaction of phenols with an amination agent in the presence of a low alkali and weakly acidic alumina catalyst having the alkali oxide content of less than 0.5% by weight, said alumina catalyst being obtained by firing an alumina catalyst containing in a dry state more than 80% by weight of alumina and less than 20% by weight of silica at a temperature of 600.degree.-900.degree. C., followed by acid treatment. According to the present invention, there are obtained such excellent effects that even when the reaction is carried out at a temperature lower than those employed in the case of conventionally well-known catalysts, the desired anilines can be prepared in high yields and high selectivity and, moreover, a high catalyst activity can be maintained over a long period of time.The alumina catalyst used in the present invention is characterized by having the alkali metal oxide content of less than 0.5% by weight and pKa of from -3.0 to +6.8 as measured by Hammett's indicator, and containing in a dry state more than 80% by weight of alumina and less than 20% by weight of silica, and this catalyst is prepared by firing an alumina catalyst containing in a dry state more than 80% by weight of alumina and less than 20% by weight of silica at a temperature of 600.degree.-900.degree. C., followed by acid treatment.
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