The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 26, 1998
Filed:
Aug. 28, 1996
Hodogaya Chemical Co., Ltd., Kanagawa-ken, JP;
Abstract
An industrially advantageous process described below has been established wherein tetrahydrofuran and a cyclic ether copolymerizable therewith are copolymerized by the use of a very small amount of a commercially available heteropolyacid as it is untreated, the heteropolyacid of the catalyst is recovered, recycled and reused in a simple way, and a high quality polyether substantially free from catalyst contaminants is obtained. A process for producing a polyether, comprising the steps of copolymerizing tetrahydrofuran and at least one cyclic ether copolymerizable therewith by the use of an untreated heteropolyacid as a catalyst in the presence of a hydroxy compound to form a reaction liquid, contacting the resulting reaction liquid with an anion exchange resin so that the heteropolyacid contained in the reaction liquid adsorb to the anion exchange resin to remove the heteropolyacid, desorbing the removed heteropolyacid from the anion exchange resin to reuse it as the catalyst, and reusing the anion exchange resin after the desorption as it is, thus to recycle and reuse both the catalyst and the anion exchange resin.