PROCESS FOR PREPARING HIGH PURITY MONOCARBOXYLIC PERFLUOROPOLYETHERS
申请人:Marchionni Giuseppe
公开号:US20090118550A1
公开(公告)日:2009-05-07
A process for preparing monocarboxylic perfluoropolyethers of formula: A-O-(R
F
)
z
-(CFY)
t
-C(O)OX (I) wherein: X is H, C
1
-C
10
alkyl, or an aryl group; Y=F, CF
3
; t=1, 2 or 3; A is a C
1
-C
4
perfluoroalkyl end group; z=0 or 1; R
F
is a perfluorooxyalkylene chain; having a number average molecular weight in the range 180-8,000; comprising the following steps: a) one or more distillations of perfluoropolyethers (PFPE) of formula T-O-(R
F
)
z
-T′ (II) wherein: z and R
F
are as above defined; T, T′, equal to or different from each other, are selected from acyl fluoride or carbonyl-containing functional end groups and non functional end groups to obtain one PFPE fraction of formula (II) wherein the difference between the minimum and the maximum molecular weight of the components is lower than or equal to 600; b) partial fluorination of the fraction obtained in a); c) esterification c1) and/or hydrolysis c2) of the mixture obtained in b); d) distillation of the product obtained in c2) or in c1).