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Abstract

A two-stage, gas phase process for manufacturing alkylene glycol (e.g., ethylene glycol) from an alkene (e.g., ethylene), oxygen and water, the process comprising the steps of:

(A) Contacting under gas phase, oxidation conditions gaseous alkene and oxygen over a heterogeneous oxidation catalyst to produce a gaseous oxidation product comprising alkylene oxide, water and unreacted alkene;(B) Contacting under gas phase, hydrolysis conditions the gaseous oxidation product of (A) with added water over a heterogeneous hydrolysis catalyst to produce a gaseous alkylene glycol and unreacted alkene; and(C) Recycling the unreacted alkene of (B) to (A).The hydrolysis catalyst is selected from the group consisting of hydrotalcites, metal-loaded zeolites, phosphates, and metal-loaded ion-exchanged molecular sieves. The process improves over the conventional two-stage process by the elimination of steps and equipment to recover and refine alkylene oxide, the use of less water in the hydrolysis reaction, and the elimination of the entire evaporation train used in the recovery of alkylene glycol.

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