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).
一种制备单羧基
全氟聚醚的方法,
化学式为:A-O-(RF)z-(CFY)t-C(O)OX(I)其中:X为H、C1-C10烷基或芳基;Y=F、
CF3;t=1、2或3;A为C1-C4
全氟烷基端基;z=0或1;RF为全
氟氧烷基链;具有分子量在180-8,000范围内的平均数;包括以下步骤:a) 对
化学式为T-O-(RF)z-T′(II)的
全氟聚醚(
PFPE)进行一次或多次蒸馏,其中:z和RF如上定义;T、T′,相等或不同,从酰
氟或含羰基末端基团和非功能末端基团中选择,以获得
化学式(II)的一个
PFPE分数,其中组分的最小和最大分子量之间的差异小于或等于600;b) 对步骤a)中获得的分数进行部分
氟化;c) 对步骤b)中获得的混合物进行酯化c1)和/或
水解c2);d) 对步骤c2)或c1)中获得的产物进行蒸馏。