| 摘要 |
<p>The new macromolecular telomers are used as stabilising agents for concentrated aqueous formaldehyde solutions. These telomers are obtained by a process which consists: a) in telomerising vinyl acetate by means of a nonhalogenated telogen agent in the presence of a free-radical generator, the telogen/vinyl acetate molar ratio being between 0.01 and 4, then, b) after optional distillation of the unreacted vinyl acetate and telogen agent, in partially acetalising the telomer formed in an organic solvent by means of formaldehyde in the presence of a strong inorganic acid, the formaldehyde/initially charged vinyl acetate molar ratio being between 0.2 and 1, preferably between 0.3 and 0.8, and finally c) in isolating the partially acetalised telomer thus obtained, by precipitation in alkaline water. Very small amounts of these stabilising agents make it possible to stabilise aqueous formaldehyde solutions.</p> |
