Refined metolachlor continuous asymmetric hydrogenation reaction process

The invention relates to a refined metolachlor continuous asymmetric hydrogenation reaction process, which adopts a chirality dual phosphine ligand-transition metal composite catalyst, and has the advantages of high activity and good enantio-selectivity, namely S/C is up to 105, the activity is greatly improved compared with an existing process, and a catalyst e.e percent is up to 99 percent. A production process adopts a continuous circulation reaction manner, through an automatic control technology, reaction pressure is reduced to 2.0-5.0MP (the reaction pressure is 10.0MPa in a traditional reaction process), the problems of difficult control over continuous asymmetric high pressure catalytic hydrogenation and safety are solved, a stable, safe, clean and efficient industrialized production is realized, and product quality, raw material consumption, three wastes and safety achieve the international advanced technical economic level. An asymmetric hydrogenation e.e percent value is up to 91 percent.