Abstract: Disclosed herein relates to pharmaceutical engineering, and more particularly to a micro reaction system and a method for preparing 2-methyl-4-amino-5-cyanopyrimidine using the same. An acetamidine hydrochloride solution and an (dimethylaminomethylene)malononitrile solution are separately pumped into the micro reaction system including a micromixer and an agitating microchannel reactor in communication at the same time for a continuous condensation-cyclization reaction to obtain 2-methyl-4-amino-5-cyanopyrimidine.

Abstract: A micro-reaction system and a method for preparing 2-methyl-4-amino-5-aminomethyl pyrimidine. A Raney nickel catalyst is modified with formalin, and the modified Raney nickel catalyst is filled into a micro-channel reactor of the micro-reaction system. A substrate solution containing 2-methyl-4-amino-5-cyanopyrimidine and a base and hydrogen are transported to the micro-mixer and the micro-channel reactor in sequence for continuous catalytic hydrogenation to obtain 2-methyl-4-amino-5-aminomethyl pyrimidine.

Abstract: A multi-layered micro-channel mixer includes a base plate and a cover plate. Two inlet fluid reservoirs, two inlet channels, two groups of fluid distribution channel networks, two groups of process fluid channels, an impinging stream mixing chamber, a fluid mixing intensification channel and an outlet buffer reservoir are provided on the base plate. Two fluids are fed into the two inlet fluid reservoirs, respectively. The fluids then flow into the process fluid channels via the inlet channels and the multi-stage fluid distribution channel networks, respectively. Then the two fluid streams ejected from the opposing process fluid channels impinges upon each other in the impinging stream mixing chamber. The mixed fluid is subjected to vortex or secondary flow generated by the baffles or the internals in the impinging stream mixing chamber and fluid mixing intensification channel, and finally the mixed fluid is discharged through the outlet buffer reservoir.

Abstract: A method for preparing L-carnitine using a micro-reaction system. (R)-4-halo-3-hydroxybutyrate was subjected to quaternization and hydrolysis in an aqueous trimethylamine solution in the presence of an inorganic base in a micro-channel reactor to produce the L-carnitine.

Abstract: This disclosure relates to organic synthesis, and more particularly to a method for preparing 3-chloro-4-oxopentyl acetate using a fully continuous-flow micro-reaction system. In this method, chlorine and an acetylbutyrolactone-containing liquid are simultaneously transported to a first micro-channel reactor for continuous chlorination to obtain ?-acetyl-?-chloro-?-butyrolactone. The reaction mixture is simultaneously transported to a micro-mixer and a second micro-channel reactor together with a mixed solution of glacial acetic acid, hydrochloric acid and water, and the continuous acylation is carried out to obtain 3-chloro-4-oxopentyl acetate. After quenched with a quenching agent, the reaction mixture was subjected to extraction and separation to obtain the 3-chloro-4-oxopentyl acetate.