Micro-reaction system and method for continuously synthesizing clethodim intermediate 5-[2-(ethylthio) propyl]-3-hydroxy-2-cyclohexene-1-ketone

The invention discloses a micro-reaction system and method for continuously synthesizing a herbicide clethodim intermediate 5-[2-(ethylthio) propyl]-3-hydroxy-2-cyclohexene-1-ketone. The system is formed by sequentially connecting a feeding pump, a micro-channel mixer, a micro-channel reactor and a quenching system in series. The synthesis method comprises the following steps: micro-mixing dimethyl malonate and a methanol solution of sodium methoxide, then enabling the mixture to enter a micro-channel reactor for reaction to obtain a sodium salt solution of dimethyl malonate, micro-mixing the sodium salt solution and 6-ethylthio-3-ene-2-heptanone (heptenone for short), then enabling the mixture to enter the micro-channel reactor for cyclization reaction, the method comprises the following steps: carrying out vacuum desolvation on a cyclization product to remove a solvent methanol, adding sodium hydroxide to carry out a hydrolysis reaction, adding hydrochloric acid to carry out a decarboxylation reaction, addi