Patent ID: 6187894
Filing Date: 2001-02-13
Classification: C08G

Abstract:
A process for obtaining (per)fluoroether acylperoxides having an average equivalent weight (EW) in the range 350-5000, having the formula:Y'--(CF.sub.2 --CF(CF.sub.3)O).sub.m --(CX'FO).sub.n --CF.sub.2 CO--O--O--CO--CF.sub.2 --(OCX'F).sub.n --(OCF(CF.sub.3)--CF.sub.2)--Y' (I)whereinY'=Cl, OR.sub.f wherein R.sub.f is a C.sub.1 -C.sub.3 perfluoroalkyl;m, n are integers such that the average equivalent weight of (I) is in the range of 350-5000 and m/n.gtoreq.40;X'=F, CF.sub.3 ;T--CF.sub.2 --O--[(CF.sub.2 CF.sub.2 O).sub.p --(CF.sub.2 O).sub.q CF.sub.2 --CO--O--O--CO--CF.sub.2 (OCF.sub.2).sub.q --(OCF.sub.2 CF.sub.2).sub.p ].sub.y --OCF.sub.2 --COOH (II)whereiny is an integer comprised between 1 and 5;p and q are integers such as to give the above mentioned EW and p/q=0.5 to 2.0;T=COOH, F with the proviso that when T=COOHy=1-5, when T=F then y=1;starting from perfluoroether acylhalides having number average molecular weights (MV) in the range of 350-5000, having, respectively, the formula:Y'--(CF.sub.2 ---CF(CF.sub.3)O).sub.m --(CX'FO).sub.n --CF.sub.2 CO--Y"" (I')wherein Y', X', m and n have the meaning defined in (I);Y""=Cl, F;Y'""CF.sub.2 --O--(CF.sub.2 CF.sub.2 O).sub.p --(CF.sub.2 O).sub.q --CF.sub.2 --CO--Y"" (II')whereinY"" has the meaning defined in (I'); Y'""=CO--Y"", F;by reaction with H.sub.2 O in basic conditions at a temperature in the range -5.degree. C. to 5.degree. C. in a mixture formed by two immiscible liquid phases having a total volume equal to at most 2/3 of that of the reactor, kept under stirring so that no emulsions are formed, said liquid phases being:an organic phase formed by (per)fluorinated solvents selected from C.sub.6 -C.sub.10 linear chain perfluoroalkanes, perfluoropolyethers having perfluoroalkylic end groups, optionally containing at one or both end groups a hydrogen atom, said perfluoropolyethers having a number average molecularweight in the range of 400-1000;an aqueous alkaline solution containing an excess of hydrogen peroxide relative to the halide added;said process comprising the following steps:a) adding a (per)fluoropolyether monoacyl or diacyl-halide, to a reactor having an internal volume in the range 50-250 ml cooled with a 2 liter volume cryogenic bath having a temperature comprised between -40.degree. C. and -80.degree. C., so that the .DELTA.T thermal rise is in the range 6.degree. C. to 20.degree. C., and such that when the addition is complete the temperature decreases to the initial temperature in a time period in the range of 0.1-5 minutes;b) conducting the ensuing reaction with stirring at the initial temperature, for a time (t.sub.max) to obtain the conversion of 75% of the acyl-halide of formula (I') or (II'), said conversion determined by quantitative FTIR; andc) interrupting the reaction by stopping stirring and allowing the phases to be separated by maintaining the system at the initial temperature, and subsequently recovering the organic phase containing the perfluoropolyether diacyl/polyacyl-peroxides.