Method for online synthesis of N-(5-sucrose ester valeryl)metoprolol by means of catalysis of lipase

The invention discloses a method for online synthesis of N-(5-sucrose ester valeryl)metoprolol by means of catalysis of lipase. The method comprises the following steps: putting N-(5-vinyl ester valeryl)metoprolol and sucrose, which is taken as raw materials, as well as dimethyl sulfoxide (DMSO) and tert-amyl alcohol, taken as reaction solvents, into an injector, wherein the ratio of amount of substance of the N-(5-vinyl ester valeryl)metoprolol to the sucrose is equal to 1 to (1-10); evenly filling a reaction channel of a microfluidic channel reactor with the lipase Lipozyme TL IM taken as a catalyst; continuously injecting the raw materials and the reaction solvents into the reaction channel under the propelling of an injection pump, and carrying out an esterification reaction, wherein the inner diameter of the reaction channel of the microfluidic channel reactor is 0.8-2.4mm, and the length of the reaction channel is 0.5-1.0m; controlling the temperature of the esterification reaction to be 20-60 DEG C and