| 摘要 |
<p>The prepn. of polycarboante oligomers by reacting an aq. alkali soln. of bisphenol A with phosgene in the presence of methylene chloride, is improved by carrying out the reaction in the presence of 1-10 mole% of an inert gas (those which have no reactivity and are gaseous at -30 to 170 degrees C at 1-10 atms. such as N2, CO, etc.) based on the phosgene. Polycarbonate oligomers having a uniform quality can be obtd.</p> |
