| 摘要 |
Gaseous monomeric formaldehyde is prepared by pyrolysing paraformaldehyde in an inert organic carrier liquid having a boiling point above the decomposition temperature of the paraformaldehyde, in the presence of an organic acid compound having at least 8 carbon atoms, which acid compound is soluble in the inert carrier liquid and is non-volatile under the pyrolysis conditions. It is preferred that the weight ratio of carrier liquid to paraformaldehyde be 0.5: 1 to 10: 1 and the organic acid compound be employed as 0.001 to 0.1 acid gram equivalents per kg. of paraformaldehyde. Specified carrier liquids are those aliphatic and cycloaliphatic saturated hydrocarbons. With 8 or more carbon atoms, halogenated benzenes, alkylbenzenes, ethers, esters, and polyethers and polyesters of molecular weight 1000-5000 that are liquid under the pyrolysis conditions. Specified acid compounds are stearic acid, palmitic acid, aliphatic dicarboxylic acids, hydroxycarboxylic acids, paraffin-sulphonic acids, alkyl-aryl-sulphonic acids, esters of sulphuric and phosphonic acids and monoesters of aliphatic and cycloaliphatic polycarboxylic acids with fatty alcohols, thiophosphoric acid esters and phosphoric acid thiol esters of fatty alcohols, sulphimides, and sulphates and phosphates of tertiary amines which contain more than 10 carbon atoms. |
