The Dow Chemical Company

Dow Global Technolgoies LLC

William J Rievert

Guo-shuh J Lee

Gary R Strickler

Von G Landon

Edward E Timm

Daniel J LaPrairie

The present invention relates to a catalytic process for the preparation of alkylene glycols from alkylene oxide and water. Further, the invention relates to a method of preservation of catalysts in alkylene oxide containing systems. More in particular, it has been found that particular acids have a positive effect on the lifetime of catalyst systems based on anion exchange resins, and particularly those in the bicarbonate form.

Process for the preparation of alkylene glycols

The present invention relates to a catalytic process for the preparation of alkylene glycols from alkylene oxide and water. Further, the invention relates to a method of preservation of catalysts in alkylene oxide containing systems. More in particular, it has been found that polycarboxylic acids, preferably oxalic acid, have a positive effect on the lifetime of catalyst systems based on anion exchange resins, and particularly those in the bicarbonate and oxalate forms.

A method for making glycol in an adiabatic reactor system including feeding water and an epoxide into at least one adiabatic reactor under conditions such that epoxide and the water react to form a glycol product stream. The adiabatic reactor contains a catalyst bed which undergoes swelling during its useful lifetime, and the adiabatic reactor operates under conditions sufficient to reduce the rate of catalyst swelling relative to a non-adiabatic reactor system. Other aspects of the invention include the combination of splitting the feed between multiple adiabatic reactors in combination with the cross exchange of heat between feeds and products with heat exchangers, such that an energy efficient process that provides long catalyst stability and minimal catalyst swelling results.

Method for making glycol in an adiabatic reactor system

A process for preparing alkylene glycols including reacting an alkylene oxide with water in the presence of a combination of additives and an anion exchange resin, wherein the combination of additives comprises carbon dioxide and an organic or inorganic base provided in an amount sufficient to maintain a pH of the reaction mixture between about 5.0 and 9.0, with the proviso that, when the base is bicarbonate or carbonate, then the anion exchange resin is a trimethyl benzyl ammonium anion exchange resin. A particularly preferred method of this invention is to react ethylene oxide with water in the presence of a halogenate or bicarbonate-type anionic exchange resin (such as a DOWEX.TM. MSA-1 type resin), carbon dioxide, and sodium hydroxide. Some advantages of this invention are that it provides desirable catalyst lifetime and activity, minimizes resin swelling, and provides a desirable, sustained selectivity to alkylene glycol.

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Beaverton, MI, United States of America

William J Rievert