Patent ID: 7683221

Claim:
A process for manufacturing alkylene glycol, the process comprising: subjecting a reaction mixture to suitable reaction conditions to thereby form a reaction product, wherein the reaction mixture comprises alkylene oxide, water and a soluble catalyst consisting essentially of a bicarbonate salt wherein the soluble catalyst has a solubility in monoethylene glycol exceeding about 5 weight percent at 25° C. and are sufficiently soluble in the product and the feed and any byproducts that said salts may be recycled without precipitating out of the recycle stream, and wherein the reaction product comprises alkylene glycol, water, the soluble catalyst and at least one reaction by-product; separating the reaction product by distillation into an alkylene glycol product stream and a first recycle stream, wherein the alkylene glycol product stream comprises alkylene glycol, and wherein the first recycle stream comprises the soluble catalyst, decomposed soluble catalyst, and the at least one reaction by-product wherein the catalyst does not precipitate out of said first recycle stream; contacting the first recycle stream with a gas comprising carbon dioxide under suitable conversion conditions to convert at least a portion of the decomposed soluble catalyst in the first recycle stream to the soluble catalyst; and subsequently combining the first recycle stream with the reaction mixture.