Crystallization of chiral compounds 3. 3-phenoxypropane-1,2-diol and 3-(2-halophenoxy)propane-1,2-diols
作者:D. V. Zakharychev、S. N. Lazarev、Z. A. Bredikhina、A. A. Bredikhin
DOI:10.1007/s11172-006-0243-x
日期:2006.2
Specific features of melting of crystalline samples of 3-(2-R-phenoxy)propane-1,2-diols with different enantiomeric compositions were studied by differential scanning calorimetry. The melting points and enthalpies of melting for the racemate and individual stereoisomers were determined. Binary phase diagrams were constructed. The entropy of mixing of individual enantiomers in the liquid phase and the free energy of formation of the racemic compound were calculated. The thermochemical data indicate that the racemates are formed upon the crystallization of phenoxy-and 2-fluorophenoxy-containing compounds, while crystallization of the chloro-, bromo-, and iodo-substituted analogs would form racemic conglomerates.
通过差示扫描量热法研究了具有不同对映体成分的 3-(2-R-苯氧基)丙烷-1,2-二醇晶体样品熔化的具体特征。确定了外消旋体和单个立体异构体的熔点和熔焓。构建了二元相图。计算了各对映体在液相中的混合熵和外消旋化合物的形成自由能。热化学数据表明,含苯氧基和 2-氟苯氧基的化合物结晶时会形成外消旋体,而氯代、溴代和碘代类似物结晶时会形成外消旋混合物。