Michael加成衍生化结合气相色谱-质谱法测定汽油馏分中的硫醇化合物

Analysis of Thiols in Naphtha With Michael Addition Derivatization Followed by Gas Chromatography-Mass Spectrometry

建立了基于Michael加成反应结合气相色谱-质谱测定汽油中硫醇化合物的方法。以苯基乙烯基砜(PVS)为衍生化试剂,4-二甲氨基吡啶(DMAP)为催化剂,甲醇为溶剂,反应迅速且各硫醇单体转化率均在99%以上。采用气相色谱-质谱(GC-MS)测定汽油中硫醇化合物单体,并对C1~C8烷基硫醇进行定量分析,同时对焦化汽油、催化裂化汽油中的烷基硫醇化合物进行定量分析。结果表明:该测定方法对于13种烷基硫醇的定量标准方程在其质量浓度为1~200 mg/L范围内呈现良好的线性关系,相关系数在0.9985~0.9997之间,加标回收率处在74.1%~124.6%,相对标准偏差(RSD)均小于5%。汽油中硫醇化合物集中分布在C2~C3的低碳数硫醇中,占总硫醇化合物的60%以上。焦化汽油中硫醇化合物含量较高,含较多的正构硫醇;而催化裂化汽油硫醇化合物含量相对较低,同碳数异构硫醇的相对含量多大于正构硫醇含量。

An analysis method based on Michael addition reaction for analyzing thiols in naphtha by gas chromatography-mass spectrometry was established.Phenyl vinyl sulfone(PVS)was selected as derivatization reagent,4-dimethylaminopyridine(DMAP)was used as catalyst,and methanol was used as solvent.The conversions of thiols are all above 99%.Quantitative analysis of 13 types alkyl thiol monomers of C1-C8 shows a good linear correlation in the range of 1-200 mg/L by GC-MS.The correlation coefficients are between 0.9985-0.9997,and the recoveries reach 74.1%-124.6%.The relative standard deviation(RSD)is less than 5%.Quantitative analysis of thiols in coker and FCC naphtha shows that the thiols of naphtha concentrate in C2-C3 of low carbon number thiols,accounting for more than 60%.Coker naphtha has a high content of the total thiols and contains more normal-alkyl thiols.Meanwhile,FCC naphtha has a lower content of thiols than that of coker naphtha.The relative content of isomeric thiols at the same carbon number is much higher than that of normal-alkyl thiols in the FCC naphtha.