用S-甲基化反应和~2H NMR、^(13)C NMR表征石油中有机硫的结构

STRUCTURAL CHARACTERIZATION OF ORGANIC SULFUR COMPOUNDS IN PETROLEUM BY S METHYLATION AND 2H NMR, 13 C NMR

提出用衍生物－ＮＭＲ表征石油中的有机硫结构的方法。在四氟硼酸银的存在下，分别用２Ｈ或１３Ｃ同位素富集的碘甲烷，把石油中的有机硫定量地转变为相应的甲基锍盐，然后用２ＨＮＭＲ和１３ＣＮＭＲ表征硫化物的结构。给出了一些模型甲基锍盐的２ＨＮＭＲ和１３ＣＮＭＲ化学位移值。分析结果表明，石油中噻吩类为苯并噻吩型等结构；硫醚为脂肪硫醚、二苯硫醚及α－萘基甲基硫醚等；阿拉伯原油样品中，大约７０％的硫化物为噻吩类化合物，其余为硫醚类化合物；有机硫化物的甲基化转化率为６５％～８７％。

A derivatization NMR method for characterization of organic sulfur compounds in petroleum and its residuum was described.The method relies on the conversion of sulfur functions to their corresponding methylsulfonium salts following by 2H NMR and 13 C NMR analysis.In the presence of silver tetrafluoroborate,twentyone sulfides and thiophenes were methylated with methyl iodide to form model methylsulfonium salts and 1H NMR and 13 C NMR chemical shift of added methyl groups (relative to TMS) were given.This S methylation was almost quantitatively except simple thiophenes such as thiophene,2 methylthiophene and 2,2′ bithiophene.Three petroleum samples,Arabian Light (ABL),Arabian Extra Light (ABX) and Arabian Residuum (ABR) were methylated with ordinary methyl iodide, 13 C enriched methyl iodide and D enriched methyl iodide,respectively,in the same reaction condition as model sulfur compounds and then analyzed by 2H NMR and 13 C NMR.The results show that benzothiophene type,dibenzothiophene type,benzonaphthothiophene type,naphthothiophene type and diaryl sulfide type structures were identified in ABL,ABX,ABR by making compa risons with model sulfonium salts.In the organic sulfur of these samples there were about 70% thiophenes and 30% sulfides.About 65%～87% of organic sulfur functions in the samples were methylated by this technique.