Patent number: H604
Abstract: A process for preparing 1,4,4,5,5,6,6-heptafluoro-2-trifluoro-3-oxaheptan,7-diol polyformal by the following steps in order:(1) reacting 2,4,4,5,5,6,6-heptafluoro-2-trifluoromethyl-3-oxaheptane-1,7-diol with formaldehyde in 80-90% (w/w) sulfuric acid in the presence of methylene chloride to produce 2,4,4,5,5,6,6-heptafluoro-2-trifluoromethyl-3-oxaheptane-1,7-diol polyformal;(2) treating the reaction mixture with aqueous H.sub.2 O.sub.2 to destroy free formaldehyde;(3) removing methylene chloride from the reaction mixture;(4) extracting the product 2,4,4,5,5,6,6-heptafluoro-2-trifluoromethyl-3-oxaheptane-1,7-diol polyformal from the reaction mixture with ether;(5) agitating the ether extract with an aqueous solution of (a) H.sub.2 O.sub.2, (b) KOH or NaOH, and (c) NaCl or KCl to convert hemiformal end groups into hydroxy end groups; and(6) isolating the product 2,4,4,5,5,6,6-heptafluoro-2-trifluoromethyl-3-oxaheptane-1,7-diol polyformal.
Type:
Grant
Filed:
July 27, 1988
Date of Patent:
March 7, 1989
Assignee:
The United States of America as represented by the Secretary of the Navy
Inventors:
Robert E. Farncomb, Horst G. Adolph