Patent ID: 8835692

Claim:
A method for preparing a polyol meeting the following general formula (I′): wherein: R′ 1 is a straight-chain or branched alkyl group comprising 1 to 14 carbon atoms, the said alkyl group optionally containing one or more side substituents —S-A 3 -OH, A l is a divalent alkylene radical, straight-chain or branched, comprising 2 to 14 carbon atoms, A 2 is a —O-A 4 -O— radical, A 4 is a divalent alkylene radical, straight-chain or branched, comprising 1 to 20 carbon atoms, optionally comprising one or more substituents, or A 2 is a radical of formula —(OCH 2 CH 2 ), n —O—, n representing an integer of between 1 to 100, A 3 is a divalent alkylene radical, straight-chain or branched, comprising 1 to 10 carbon atoms, optionally substituted, Y′ is a hydrogen atom or a group of formula (A′) A 1 , A 3 and R′ 1 being such as defined above in formula (I′), the said method comprising the following steps: a) a transesterification step of a compound of following formula (II′): A l being such as defined above in formula (I′), R″ 1 representing a straight-chain or branched alkyl group comprising 1 to 14 carbon atoms, the said alkyl group optionally containing one or two double bonds, and R 2 representing a straight-chain or branched alkyl group comprising 1 to 10 carbon atoms, with a diol of following formula (III): H-A 2 -H (III) A 2 being such as defined above in formula (I′), to obtain a compound of following formula (IV′): A 1 , A 2 and R″ 1 being such as defined above, and, Y″ representing a hydrogen atom or a group of formula (A″) A l and R″ 1 being such as defined above, b) a thiolation step of the compound of above-mentioned formula (IV′) to obtain a compound of formula (I′) such as defined above, and c) a step to collect the compound of formula (I′) such as defined above.