Patent · US Expired

Continuous preparation of phosphoric acid alkyl ester dichlorides

US4296047A · kind A · utility

1Cited by

4References

7Claims

0Family size

Assignee

BAYER HEALTHCARE LLC · DE

Inventors

Karl-Julius Schmidt
Friedrich Schmidt · Wuppertal, DE
Peter Siegle · Cologne, DE
Gert Hansen · São Paulo, BR

Key dates

Filing date	Mar 12, 1980
Grant date	Oct 20, 1981
Priority date	—
Expiry date	Mar 12, 2000

Classification

Technology area (CPC C)Chemistry; Metallurgy
CPC primaryC07F9/14
WIPO fieldOrganic fine chemistry
WIPO sectorChemistry

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.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.