PROCESS FOR THE PURIFICATION OF POLYOL PFPE DERIVATIVE

摘要

The invention pertains to a process for the purification of a tetraol PFPE derivative [tetraol (T)] of formula (I): HO-CH2-CH(OH)-CH2-O-CH2-CF2-O-Rf-CF2-CH2O-CH2-CH(OH)-CH2OH (I), wherein Rf represents a fluoropolyoxyalkene chain (chain Rf), i.e. a fluorocarbon segment comprising ether linkages in main chain, from a mixture of hydroxyl (per)fluoropolyether derivatives [mixture (M)], said mixture comprising said tetraol (T) and at least one hydroxyl (per)fluoropolyether [PFPE (OH)] comprising a chain Rf terminated with at least one end group of formula: -CF2CH2OH) -CF2CH2O-CH(OH)-CH2-O-CH2-CH(OH)-CH2OH; said process comprising: step 1 : reacting the mixture (M) with ketones and/or aldehydes so as to selectively protect couples of hydroxyl groups on vicinal carbon atoms by forming corresponding cyclic ketal/acetal derivatives, so as to yield a protected mixture [mixture (P)]; step 2: reacting residual hydroxyl groups of the mixture (P) with suitable functionalizing agents enabling substantial volatility modification, so as to obtain a functionalized protected mixture [mixture (Pf)]; step 3: fractional distillation of the mixture (Pf) so as to isolate the cyclic acetal/ketal derivatives of tetraol (T); step 4. hydrolyzing the acetal/ketal derivatives of tetraol (T) so as to recover pure tetraol (T).