| 摘要 |
<p>1,181,772. Recovering formaldehyde. SOC. ITALIANA RESINE S.p.A. 26 July, 1968 [1 Aug., 1967], No. 35910/68. Heading C2C. [Also in Division C3] The vapours obtained in the stabilization of polyoxymethylenes by degradative reaction with anhydrides in an appropriate solvent are rectified in a fractionation column, the anhydride-solvent mixture being obtained at the base and the solvent-formaldehyde mixture being obtained at the top. The latter mixture may then be treated, e.g. with water or cyclohexanol to extract the formaldehyde as formalin or cyclohexanolhemimethylal. A suitable solvent is toluene.</p> |
