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:
Oct. 09, 1990
Filed:
Apr. 05, 1989
Asahi Kasei Kogyo Kabushiki Kaisha, Osaka, JP;
Abstract
A process for producing formaldehyde having high purity is disclosed, which comprises: (A) feeding crude formaldehyde containing water and methanol to the middle or lower part of a distillation column, and feeding a polyalkylene oxide compound which is inert to formaldehyde to the upper part of the column in an amount at least 10 times the total weight of the water and methanol contained in the crude formaldehyde; (B) carrying out distillation; and (C) recovering purified formaldehyde gas from the top of the column while withdrawing a solution containing the polyalkylene oxide compound, water and methanol from the bottom of the column. Using this process, formaldehyde having stable high purity can be obtained continuously through simplified steps at low cost.