| 摘要 |
Formaldehyde is polymerized in an inert solvent with 1 to 50% based on the monomer mixture of a cyclic formal in the presence of 0.01 to 1.0% of a cationic catalyst at +20 to +100 DEG C. Specified cyclic formals are 1,3-dioxolane, 4 - phenyl - 1,3 - dioxolane, 1,3-dioxane, 5 - dimethyl - 1,3 - dioxane, 1,3-dioxoacyclopeptane, 1,3,6 - trioxyacyclooctane, 1,4 - butane diol formal and diethylene glycol formal. Specified catalysts are the halides of boron, aluminium, titanium, zinc, iron and especially antimony or tin and their complex compounds with, e.g. ethers or organic acids and the oxonium compounds of these halides, e.g. triethyl oxonium fluoroborate or their diazonium complex compounds, e.g. p-nitrophenyl diazonium fluoroborate-preferred catalysts are SbCl5 and SnCl4 and [(C6H5)3O] SbCl6 and [(C2H5)3O]SnCl6. The polymerization may take place in a mixture of solvents. Specified are aliphatic or aromatic hydrocarbons, halogenated hydrocarbons and ethers. The formaldehyde may be added and the polymerization batch then stirred for 10 minutes to 5 hours at 20 DEG to 100 DEG C., the polymer sucked off, and treated with a base before or after washing with a solvent. |
