用超临界气体抽提方法研究抚顺烟煤的组成和结构——Ⅰ.抽出物的分离及GC、GC/MS分析

将抚顺烟煤用甲苯作溶剂,在半连续抽提装置上,于350℃、20MPa条件下,进行超临界气体抽提。抽出物先分离成油、沥青烯及前沥青烯三个族组份,再用离子交换树脂、硅胶柱色谱作进一步分离。GC和GC/MS的分析结果表明,油段分中存在正构烷烃(C_(13)—C_(31))、类异戊二烯化合物及长链烷基苯系列,这些化合物可提供抚顺烟煤的地球化学信息。     

Electrochemical oxidation of 6-hydroxy-1,2,3,4-tetrahydro-β-carboline in aqueous solution

The electrochemical oxidation of 6-hydroxy-1,2,3,4-tetrahydro-β-carboline (1), an alkaloid which occurs naturally in the mammalian brain, has been studied in aqueous solution particularly at physiological pH. The first voltammetric oxidation peak of 1 observed at the pyrolytic graphite electrode generates a radical intermediate which dimerizes to give 5,5′-bi-(6-hydroxy-1,2,3,4-tetrahydro-β-carboline) (3). However, the putative radical intermediate can also be further oxidized (1e) to give a C(5)-centered carbocation which can either dimerize in an ion-substrate reaction to give 3 or be attacked by water to give 5,6-dihydroxy-1,2,3,4-tetrahydro-β-carboline (8) which is rapidly oxidized further to 1,2,3,4-tetrahydro-β-carboline-5,6-dione (9). In the presence of glutathione dione 9 forms the 8-S-glutathionyl conjugate of 8 which is easily oxidized to the 8-S-glutathionyl conjugate of 9. It is suggested that 1 might be an alkaloid which is elevated in the brain as a result of chronic alcoholism, and the roles of the oxidative transformations of this compound in some of the addictive and neurophathological consequences of ethanol consumption are discussed.