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. 03, 1977
Filed:
Apr. 18, 1975
Noboru Shimizu, Takatsuki, JA;
Sadao Yoshida, Suita, JA;
Kunihiro Kubota, Takatsuki, JA;
Takashi Ohara, Nishinomiya, JA;
Nippon Shokubai Kagaku Kogyo Co., Ltd., Osaka, JA;
Abstract
A method for inhibiting the polymerization of acrylic acid or acrylic esters during the distillation for separating or purifying the acrylic acid obtained by the vapor phase catalytic oxidation of propylene or acrolein, or the acrylic esters derived from said acrylic acid, said method comprising carrying out the distillation operation in the presence of (A) at least one compound selected from the group consisting of hydroquinone, hydroquinonemonomethyl ether, cresols, phenols, t-butyl catechol, diphenylamine, phenothiazines and methylene blue (B) at least one compound selected from the group consisting of copper dimethyldithiocarbamate, copper diethyldithiocarbamate copper dibutyldithiocarbamate and copper salicylate: and (C) molecular oxygen.