Co-production preparation method of monoalkyl aliphatic tertiary amine and dialkyl aliphatic tertiary amine

The invention belongs to the field of chemical engineering, particularly relates to the field of production of fatty tertiary amines, and provides a co-production preparation method of monoalkyl fatty tertiary amines and dialkyl fatty tertiary amines, which comprises the following steps: mixing fatty alcohol and a catalyst, putting the mixture into a reaction device, and activating the catalyst; introducing methylamine mixed gas consisting of monomethylamine and dimethylamine into the reaction device, heating the reaction device to 190-230 DEG C while introducing the methylamine mixed gas, and controlling the flow rate of the methylamine mixed gas so that the methylamine mixed gas can be completely introduced within 4-6 hours; after the methylamine mixed gas is completely introduced, continuously carrying out heat preservation reaction for 1 +/-0.2 hours; and carrying out post-treatment on a crude product obtained by the reaction to respectively obtain the monoalkyl fatty tertiary amine and the dialkyl fatty