| 摘要 |
<p>1,204,599. Stabilizing and purifying glycollide and lactide. AMERICAN CYANAMID CO. 6 Nov., 1968 [16 Nov., 1967], No. 52690/68. Heading C2C. Glycollide and lactide are stabilized by immersion in t-amyl alcohol and/or t-butyl alcohol, the composition containing 15-75% lactone and the liquid being essentially anhydrous and free from lactone reactive impurities prior to immersion of the lactone therein. Glycollide and lactide may be purified by immersing an impure lactone distillate in agitated t-amyl and/or t-butyl alcohol maintained at a temperature below the melting-point of the lactone, and then, if desired, after a storage period, adding additional alcohol and heating to dissolve the lactone, cooling to produce lactone crystals, and repeating the crystallization as required. The lactone may be derived from thermal cracking of low polymers. t-Amyl and t-butyl alcohols are purified by standing overnight with a small proportion of glycollide or lactide, distilling and drying the distillate with a molecular sieve.</p> |
