Union Carbide Corporation

John W Crandall

Louis A Kapicak

Charles A Gibson

Bernard C Ream

Fedor Poppelsdorf

Donald C Best

David P Higley

James E Deitzler

Gary L Culp

Scott M Farquhar

A process is described for recovering polyester-grade ethylene glycol from crude ethylene glycol containing at least one component which has a normal boiling point below that of ethylene glycol, and which can form a UV absorber in the presence of ethylene glycol which comprises supplying to an ethylene glycol distillation system, preferably comprising a fractional distillation zone having an upper portion, a lower portion and an intermediate portion a crude ethylene glycol stream at a determined pH of less than about 7.5; maintaining within the intermediate portion of the fractional distillation zone a diluent having a boiling point below that of the at least one component, such as methanol, at a concentration sufficient to reduce the formation of UV absorber in the intermediate portion wherein at least ethylene glycol, the at least one component and the diluent, are present, and withdrawing ethylene glycol substantially free of the at least one component from the lower portion of the fractional distillation zone.

Process for refining ethylene glycol

A method is disclosed for separating alkyleneamines from a mixture of by-product alkali or alkaline earth metal chloride salt and alkyleneamines comprising the sequenced combination of the steps of: (a) washing said amine-chloride salt mixture with an aqueous alkali or alkaline earth metal hydroxide solution to form a washed amine-chloride salt mixture; and (b) treating a mixture of the amino and chloride salt to physically separate chloride salt from said amine of said mixture.

Recovery of amines from by-product chloride salts

A process is provided for the utilization of dialkyl carbonates formed as by-products in a continuous process for the synthesis of oxalic acid esters from nitrous acid esters and carbon monoxide and wherein the esters are subsequently used as intermediates in the production of commercially useful products, such as ethylene glycol. The process comprises contacting a mixture containing the by-product comprised of a dialkyl carbonate with an aqueous solution of a metal carbonate under hydrolyzing conditions whereby the dialkyl carbonate is converted to the corresponding alkanol and the metal carbonate is converted to metal bicarbonate. Upon distillation of the alkanol from the mixture the bicarbonate is converted back to the metal carbonate which can then be recycled from the bottoms to the hydrolyzing zone for use in further hydrolysis of by-product. The alkanol is recycled for use in the continuous process.

Process for the hydrolysis of dialkyl carbonates

A process is provided which may be run continuously for producing polyethylene polyamines having improved color characteristics which comprises treating discolored polyethylene polyamines with polyethylene polyamine hydrochloride in the presence of water at elevated temperatures for the time necessary to reduce the color of said polyethylene polyamines and then flash evaporating the decolorized polyethylene polyamines from the treating mixture.

Method of preparing polyethylene polyamines having improved color

This invention is concerned with a continuous process for separating higher boiling, heat sensitive components from a liquid product stream. It involves a rapid evaporation of the desired product of the stream in an evaporator which minimizes residence time, such as a falling film evaporator, and feeding the vapors and the remainder of the stream to a separation column where the vaporized products rise in the column. Part of the vaporized products are removed after condensation and then recycled back to the column as a reflux. This reflux after contacting one or more trays is collected and recycled to the evaporator and mixed with the product feed being treated. The liquid remainder of the feed stream is collected at the bottom of the column. The bottom of the column can be kept at a temperature which minimizes any breakdown of the heat sensitive components present therein and, if desired, the bottoms in the column can be quickly withdrawn for treatment elsewhere or for recycling back to the process. A desirable embodiment is to recycle a portion of the residue at the bottom of the column back to the evaporator.

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Charleston, WV, United States of America

John W Crandall