| 摘要 |
An ether of a polyhydric alcohol is prepared by reacting the alcohol with a hydrocarbon monohalide and an amount of alkali metal hydroxide which is at least equivalent to the hydrocarbon halide in dimethyl sulphoxide solution at a temperature not above the boiling point of dimethyl sulphoxide. Polyhydric alcohols specified are: glycerol, trimethylol ethane, trimethylol propane, butane-1,2,4-triol, hexane-1,2,5- or 1,2,6-triol, pentaerythritol, dipentaerythritol, mannitol, sorbitol, 2,2,4-trimethylolpentanol, 2,5 - dimethylolhexane-1,6 - diol, hexane - 1,3,4,6 - tetrol, 3,3,3 - trimethylolpropane - 2 - ol, 1,1 - dimethylol-butane - 3 - ol, 3,3 - dimethylolbutane - 2 - ol, 2,2,2 - trimethylol - 1 - phenylethanol, 2,2,6,6-tetramethylolcyclopentane - 1 - ol, 2,2,6,6-tetramethylolcyclohexane - 1 - one or mixtures thereof. The hydrocarbon halide may be added at such a rate that reflux occurs. Halides specified are: ethyl, propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl, cyclopentyl, cyclohexyl, cyclopentenyl, cyclohexenyl, benzyl, a -phenylethyl, b -phenylethyl, allyl, a -methallyl, b -methallyl, crotyl and diphenylmethyl chlorides, bromides and iodides. The quantity of dimethyl sulphoxide may be 0.5-2 moles per mole of alcohol. The reaction temperature may be 50-180 DEG C. and the pressure may optionally be superatmospheric. The alkali metal halide formed may be filtered off and the water also formed may be distilled off under reduced pressure. Alternatively, an entrainer may be added to the mixture. Specified entrainers are: benzene, toluene, xylene, n-hexane, heptane, n-octane, or nonane, cyclohexane, chlorobenzene or mixtures thereof. The hydrocarbon halide may be added whilst the water azeotrope is being driven off from the alcohol/alkali/solvent/entrainer mixture. The dimethyl sulphoxide may be distilled under reduced pressure and the remaining ether mixture may be fractionally distilled. The recovered solvent may be re-used. The ether may contain free hydroxyl groups. |
