Patent ID: 7087800

Claim:
A process for producing a polyol by reacting an aliphatic aldehyde represented by formula (i): wherein R 1 and R 2 each represent hydrogen atom or an aliphatic alkyl group having 1 to 6 carbon atoms, with formaldehyde in a presence of a basic catalyst, which process comprises (1) a step of concentration which comprises removing water and unreacted formaldehyde from a reaction liquid by distillation; (2) a step of extraction which comprises extracting the polyol from a concentrated reaction liquid with an extracting reagent; and (3) a step of washing with water which comprises washing an extract liquid with water and separating the liquid into an oil layer containing the polyol and an aqueous layer; wherein an aliphatic aldehyde represented by formula (ii): wherein R 3 represents hydrogen atom or an aliphatic alkyl group having 1 or 2 carbon atoms and R 4 represents an aliphatic alkyl group having 1 to 5 carbon atoms is used as the extracting reagent, and the extracting reagent is recovered after adjusting pH of the oil layer containing the polyol which is separated in the step of washing with water, the pH being adjusted in a range of 6.0 to 9.0.