Synthesis Of N, N-Dimethylcyclohexanamine With Cyclohexane And Methanol

N,N-Dimethylcyclohexanamine is a kind of important raw material in organicchemical engineering. It can be used as ideal catalyst of producing plastic, additive ofoil, bactericide, disinfector, dyestuff and anlistatig so on. So high purityN,N-Dimethylcyclohexanamine can bring us considerable benefit. This paper hasstudied the synthesis of N,N-Dimethylcyclohexanamine by N-methylation withcyclohexane and methanol. Selection of catalyst and the optimal condition of reactionare the most important content in this paper.A series of different content AlPO₄-Al₂O₃ catalysts are prepared by gel method.It shows that as the catalyst of N-methylation with cyclohexane and methanol,AlPO₄-Al₂O₃ including 25wt% Al₂O₃ possesses very high activity and selectivity toN,N-Dimethylcyclohexanamine. The optimal condition of reaction is that reactiontemperature is 300 ℃, LHSV is 0.8h-1 and the molar rate of cyclohexane andmethanol is 1:5. Under the optimal condition of reaction, the conversion ofcyclohexane is 77%, the selectivity of N,N-Dimethylcyclohexanamine is 70% and thetotal selectivity of N-methyl Cyclohexylamine and N,N-Dimethylcyclohexanaminecan be more than 97%.By the characterization on the catalyst, it finds that AlPO₄-Al₂O₃ including25wt% Al₂O₃ belongs to the catalyst with moderate acidity and possesses amorphousstructure.