TWO-STEP METHOD FOR PREPARING N-METHYLANILINE Russian patent published in 2004 - IPC

FIELD: organic chemistry, chemical technology.

SUBSTANCE: invention proposes two-step method for preparing N-methylaniline by paraphase catalytic N-alkylation of aniline with methanol. On the first step aniline and methanol are fed in the mole ratio = 1:2 and process is carried out at temperature 230-260 C and contact loading value 0.7-0.9 h^-1 up to the conversion degree of aniline to N-methylaniline 85-95%. Catalysate is fed to the second step (additional alkylation) and process is carried out at 220-240 C up to the conversion degree of aniline to N-methylaniline above 98%. In both steps copper oxides-base catalysts are used promoted with metal oxides from the group including manganese, iron, chrome, nickel, cobalt. The depleted catalyst from the first step can be used as a catalyst on the second step and its activity is 60-70% of the initial activity. Invention provides preparing catalysate with mass part of N-methylaniline in oily fraction above 98% that provides possibility to isolate the marketing product by simplified schedule of rectification, reducing energy consumption, prolonged time for catalyst exploitation.

EFFECT: improved preparing method.

2 cl, 1 sch, 2 tbl