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:
Aug. 10, 1993
Filed:
Sep. 16, 1991
Rudolf Maul, Lorsch/Hessen, DE;
Volker Schenk, Bensheim, DE;
Ciba-Geigy Corporation, Ardsley, NY (US);
Abstract
A process for the preparation of tris-(2,4-ditert-butylphenyl) phosphite from 2,4-ditert-butylphenol and phosphorus trichloride in the presence of catalysts, which comprises carrying out the reaction in an at least three-stage process in which the 2,4-ditert-butylphenol and 40-100% of the catalyst are combined in a preliminary stage and are brought together with the phosphorus trichloride in a first stage, these being allowed to react under normal pressure and at temperatures of 55.degree. to 70.degree. C. for a dwell time of 15 to 40 minutes, the reaction mixture is then reacted in a second stage under normal pressure and at temperatures of over 140.degree. C., remaining amounts of catalyst being added to the first and/or second reaction stage, the reaction mixture is then kept under reduced pressure at temperatures of at least 186.degree. C. in a third reaction stage, and the tris-(2,4-ditert-butylphenyl) phosphite is then isolated from the reaction mixture, the process being carried out in the absence of solvents.