Hydrofluoroethers having at least one hydrogenated -OCFX'CH3 end group wherein X'=F, CF3 and their preparation process

Abstract

Hydrofluoroethers of formula:

T-CFX′—O—R_f—CFX-T′  (II)

wherein:

• T=CH₃;
• X, X′, equal to or different from each other, are selected between F, CF₃;
• T′=F, Cl, H, C₁—C₃ perfluoroalkyl, CH₃, CH₂0H, COC₁, CHO, CO₂H;
• R_f is a perfluoroalkylene or a perfluoropolyoxyalkylene and respective preparation process by reduction with hydrogen in the presence of a platinum catalyst supported on metal fluorides of the corresponding compounds with at least one —COCl end group.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This is a Divisional Application, which claims the benefit of pending U.S. patent application Ser. No. 10 / 630,697, filed Jul. 3, 2003. The disclosure of the prior application is hereby incorporated herein in its entirety by reference.BACKGROUND OF THE INVENTION [0002] The present invention relates to hydrofluoroethers characterized in having at least one hydrogenated —OCFX′CH3 end group wherein X′=F, CF3 and their preparation process. [0003] More specifically, the preparation process relates to the reduction with H2, in the presence of platinum catalysts (Pt), of the corresponding fluorinated acylchloride precursors. [0004] Hydrofluoroethers prepared by direct fluorination with F2 or electrochemical fluorination of an ether compound or by alkylation of fluorinated alcohols are known. [0005] In patent application WO 99 / 47,480 it is shown that hydrofluoroethers can be obtained by alkylation of fluorinated carbonyl compounds. The above meth...

AI Technical Summary

Problems solved by technology

The above methods employ starting compounds having a low molecular weight with a number of carbon atoms equal to or lower than 12, besides they give low yields and selectivity, and do not give hydrofluoroethers having at least one OCFX′CH3 end group with X′=F, CF3.

The reaction shows the limitation that to obtain acceptable conversions it is necessary to use CH3F as alkylating agent, has the drawback to require the use of Lewis acids which are aggressive and need the use of pressure resistant equipments built in special substances.

Furthermore HF forms, producing further problems in the equipment choice.

Since the alkylation reaction is an equilibrium reaction, it does not allow the obtainment of hydrofluoroethers with a high yield.

Besides they found application for the wide range of utilization temperatures as substituents of HFCs which in some cases have a limited application as refrigerants due to their very low boiling temperature or their very high freezing point.