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. 20, 1981
Filed:
Mar. 12, 1980
Karl-Julius Schmidt, Wuppertal, DE;
Friedrich Schmidt, Wuppertal, DE;
Peter Siegle, Cologne, DE;
Gert Hansen, Sao Paulo, BR;
Bayer Aktiengesellschaft, Leverkusen, DE;
Abstract
In the preparation of a phosphoric acid alkyl ester dichloride by reacting phosphorus oxychloride with an aliphatic alcohol according to the equation ##STR1## in which R represents C.sub.1 -C.sub.5 -alkyl, the improvement which comprises carrying out the reaction continuously at a temperature of about 10.degree. to 50.degree. C. using an excess of phosphorus oxychloride of about 5 to 40%. The excess phosphorus oxychloride is reacted with the alcohol by continuous mixing, the reaction mixture is cooled, substantially all the hydrogen chloride formed is then separated off in a preliminary degassing stage, the reaction mixture is worked up in a distillation column, the unreacted phosphorus oxychloride and any diluent is separated off over the top and condensed, the condensate is recycled to the reaction and the corresponding alkyl ester dichloride is removed continuously as the bottom product.