Patent ID: 8664353

Claim:
A process for the purification of a polyol (per)fluoropolyether derivative [polyol (P)] from a mixture of hydroxyl(per)fluoropolyether derivatives [mixture (M)], said polyol (P) comprising one or more hydroxyl(per)fluoropolyether derivatives [PFPEs (OH)] comprising at least one (per)fluoropolyoxyalkylene chain (chain R f ) and at least one end-group having formula (t 3 ): —CF 2 CH 2 OCH 2 CH(OH)CH 2 OCH 2 CH(OH)CH 2 OH said mixture (M) comprising said polyol (P) and at least one hydroxyl(per)fluoropolyether derivative [PFPE (OH)], said PFPE (OH) being different from said polyol (P) and comprising at least one (per)fluoropolyoxyalkylene chain (chain R f ) and at least one end-group selected from the group consisting of end-groups having formula (t 1 ): CF 2 CH 2 OH and end-groups having formula (t 2 ): CF 2 CH 2 OCH 2 CH(OH)CH 2 OH, said process comprising the following steps: step 1: reacting said mixture (M) with a ketone, an aldehyde, or a combination thereof so as to yield a corresponding mixture of cyclic ketal/acetal (per)fluoropolyether derivatives [PFPEs (OH) p ] [protected mixture (P)]; step 2: submitting said protected mixture (P) to adsorption on a silica gel so as to yield an adsorbed protected product [adsorbed product (P p )] and then recovering a desorbed protected product [desorbed product (P p )] by subsequent desorption from said silica gel of said adsorbed product (P p ); step 3: distilling said desorbed product (P p ) under reduced pressure so as to isolate a protected product residue [product (P r )]; and step 4: hydrolyzing said product (P r ) so as to obtain said polyol (P).