Preparation method of polyethylene glycol fatty acid ester

The present invention discloses a method for preparing a polyethylene glycol fatty acid esters, comprising the steps of: polyethylene glycol with a fatty acid methyl ester in a molar ratio of 1: 1-2.5 transesterification, the reaction temperature is 70-160 pressure ℃, the reaction of -0.95 to -0.98MPa, the reaction time is 1-10h. The reaction conversion rate of the present invention, the resulting less polyethylene glycol fatty acid ester impurities, high purity, while the reaction temperature is low, time is short, the process saves energy, but also to avoid the presence of the agent with ester there is the disadvantage of the reaction, reducing the operational aspects of the safety and economy have greatly improved.