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:
Jun. 09, 1987
Filed:
Aug. 28, 1984
Heinz Wallisch, Eltville, DE;
Uth H Felcht, Bad Soden-Neuenhain, DE;
Michael Kostrzewa, Wiesbaden, DE;
Hoechst Aktiengesellschaft, Frankfurt, DE;
Abstract
Disclosed is a process for the purification treatment of liquid reaction and/or washing media obtained in the preparation of cellulose ethers which comprises distilling and subsequently ultrafiltering the media. In the distilling step, the low-boiling organic by-products of the reaction, the residual, non-reacted, low-boiling organic reaction components and/or the optionally used organic solvents are separated in the form of a distillate. The aqueous distillation residue, which particularly comprises salts, a cellulose constituent and possibly medium and/or high-boiling organic by-products of the reaction and/or non-reacted organic reaction components, is thereafter subjected to ultrafiltration. Ultrafiltration results in a permeate, in which the COD values are, for example, reduced by about 20% by weight.