Chemical Structures and Chemical Modification of Condensed Tannin.

1.缩合单宁的化学组成和性质。选择合适的苯核交换试剂组成、反应温度和反应时间来评价缩合单宁的性质或酚类模式。此外，还讨论了用去甲苯单宁中分离出的黄酮醇二聚体进行NE法测定其纯度和酚性时应注意的问题。然后，对连续提取的卡拉松树皮提取物进行了表征，并与金合欢单宁和奎布拉乔单宁进行了比较。用NE法和另一种分析方法得到的结果表明，外层树皮含有大约两倍于重量的萃取物，但涉及的破坏性A环的数量多于内层树皮。单体模型的酚化和NE-反应机理。研究了(+)-儿茶素在苯酚-BF_3体系中的酚化反应和NE-反应行为，并分离和鉴定了反应过程中形成的三个化合物。根据实验结果，讨论了酚化反应和NE-反应的机理，并在温和的反应条件下发现了开环和酚化柔性化合物的形成，说明了通过酚化反应将单宁的刚性结构转化为柔性多价酚聚合物的可能性。缩合单宁的化学修饰为了通过酚化反应将刚性单宁分子转化为柔性的、更均匀的亲核苯酚聚合物，考察了一种酚醛介质和酸催化剂的加入量对酚化反应行为的影响。最佳反应条件为：间苯二酚100g，H_2SO_4 0.05摩尔，反应温度120℃-2小时。在此条件下得到的酚化单宁的电离速度和与亲核试剂的反应速度比原始单宁快得多。

1. Chemical Analysis and Characteristics of Condensed Tannins. Appropriate compositions of the phenyl Nucleus-Exchange (NE) reagent, reaction temperature and the time were selected to evaluate the characteristics or the phenolic patterns of condensed tannins. Furthermore, the necessary care to be taken on determining the purity and the phenolic characteristics by the NE method were discussed by the use of a flavonol dimer isolated from Quebracho tannin. After then, Karamatsu barks extractives by the successive extraction were characterized, compared with Wattle and Quebracho tannins. The results obtained by the NE-method and the other analytical method indicated that the outer bark contained about twice of the extractives by weight, but involved the more amount of the destructive A-rings than the inner bark.2. Mechanisms of the Phenolation and the NE-reaction for a Monomeric Model. The behavior of the phenolation and the NE-reaction in the phenol -BF_3 system for (+)-catechin was followed and further, three compounds formed during the reaction were isolated and identified. From the results, we discussed the mechanisms of the phenolation and the NE- reaction, and recognized the formation of the ring opening and phenolated flexible compound under the mild reaction conditions, indicating the convertible possibility of rigid structure of tannins to the flexible polyvalent phenol-polymers by the phenolation.3. Chemical Modification of Condensed Tannin. In order to convert the rigid tannin molecules into the flexible and more uniform nucleophilic phenol-polymer by the phenolation, the effects of a kind of phenolic medium and the added amount of acid catalyst on the behavior of the phenolation were examined. The selective condition was 100g of resorcinol and 0.05mols of H_2SO_4, and 120C-2hrs. The rate of ionization and the reaction with a nucleophilic reagent of phenolized tannin obtained by such the conditions was much faster than that of original tannin preparation.