Patent GB-978753-A (GB)
Title: Process for oxyalkylating polyols
IPC: C07H15/08
Filed: 1961-03-23
Abstract: Solid polyols having 3 to 8 hydroxyl groups per molecule and a melting point of at least 100 DEG C. are oxalkylated by heating, in a water-free system, with a vicinal alkylene oxide and an oxyalkylation catalyst and an adduct of a polyol having 3 to 8 hydroxyl groups per molecule and a melting point of at least 100 DEG C. with from 1 to 4 mols. of at least one vicinal alkylene oxide. The temperature is preferably 80 to 160, especially 125 DEG C. The adduct is made by heating the polyol with the alkylene oxide in an aqueous medium in the presence of an oxyalkylation catalyst at preferably not above 115 DEG C. especially at 90-100 DEG C., after which it is stripped of water and other volatile compounds. Preferably 1-2 mols. of alkylene oxide are used per mol of polyol and the quantity of water present is sufficient to dissolve at least 2% of the polyol charge. The adduct may be made from the same or a different polyol from the one to be oxyalkylated. All reactions are preferably effected under autogenous pressure in closed reaction vessels. Specified alkylene oxides are ethylene, propylene, 1, 2- and 2, 3-butylene, isobutylene, styrene, butadiene mono- and di- and cyclohexene oxides, and methyl and phenyl glycidyl ethers. Mixtures of alkylene oxides may be used. Preferably the alkylene oxides have at least 3 carbon atoms. Polyols specified are pentaerythritol, di- and tri-pentaerythritol, inositol, trimethylolethane, sucrose, glucose, fructose and sorbitol.  The catalysts are preferably basic e.g. amines and alkali metals and their hydroxides and alcoholates. When amines are used products with molecular weights of less than 600 are obtained. Indicated catalyst concentrations range from 1 to 15 mol per cent of alkali metal hydroxide based on polyol.  High concentrations of catalyst give high molecular weight products e.g. 1,000 to 10,000. In a continuous form of the process polyol and 2 to 4 mols of an alkylene oxide containing at least 3 carbon atoms, are treated with a preformed water-free adduct, from polyol and an alkylene oxide containing at least 3 carbon atoms, in the presence of the catalyst and the adduct product is withdrawn and partly recycled whilst the rest is treated with an alkylene oxide to form the oxyalkylated product. Examples describe the treatment of pentaerythritol, dipentaerythritol, trimethylol ethane and sorbitol with propylene oxide. Specifications 831,900 and 832,601 are referred to.ALSO:Solid polyols having 3 to 8 hydroxyl groups per molecule and a melting point of at least 100 DEG C. are oxyalkylated by heating, in a water-free system, with a vicinal alkylene oxide and an oxyalkylation catalyst and an adduct of a polyol having 3 to 8 hydroxyl groups per molecule and a melting point of at least 100 DEG C. with from 1 to 4 moles of at least one vicinal alkylene oxide. The temperature is preferably 80 DEG  to 160 DEG C. The adduct is made by heating the polyol with the alkylene oxide in an aqueous medium in the presence of an oxyalkylation catalyst at preferably not above 115 DEG C., after which it is stripped of water and other volatile compounds. Preferably 1-2 mols of alkylene oxide are used per mol of polyol and the quantity of water present is sufficient to dissolve at least 2% of the polyol charge. The adduct may be made from the same or a different polyol from the one to be oxyalkylated. All reactions are preferably effected under autogenous pressure.  Alkylene oxides specified are ethylene, propylene, 1,2- and 2,3-butylene, isobutylene, styrene, butadiene mono- and di- and cyclohexene oxides, and methyl and phenyl glycidyl ethers. Mixtures of alkylene oxides may be used. Preferably the alkylene oxides have at least 3 carbon atoms. Polyols specified are pentaerythritol, di- and tri-pentaerythritol, inositol, trimethylolethane, sucrose, glucose, fructose and sorbitol. The catalysts are preferably basic, e.g. amines and alkali metals and their hydroxides and alcoholates. When amines are used, products are obtained with molecular weights of less than 600. High concentrations of catalyst give high molecular weight products e.g. 1,000-10,000. In a continuous form of the process, polyol and 2 to 4 mols of an alkylene oxide containing at least 3 carbon atoms, are treated with a preformed water-free adduct, from polyol and an alkylene oxide containing at least 3 carbon atoms, in the presence of the catalyst and the adduct product is withdrawn and partly recycled whilst the rest is treated with an alkylene oxide to for the oxyalkylated product. Examples describe the treatment of pentaerythritol, dipentaerythritol, trimethylolethane and sorbitol with propylene oxide.  Specifications 831,900 and 832,601 are referred to.