焦化汽油中硫化物类型分布的气相色谱-硫化学发光检测方法

建立了焦化汽油中硫化物类型分布的气相色谱-硫化学发光检测分析方法。考察了色谱条件对焦化汽油中各种硫化物分离的影响,定性了某焦化汽油中的74个硫化物。以硫化氢、乙硫醇、正丙硫醇、噻吩、2-甲基噻吩、2-乙基噻吩、2-丙基噻吩、碳四噻吩(tR=40.28 min)、苯并噻吩、甲基苯并噻吩(tR=58.13 min)的保留时间为尺度,计算了焦化汽油中各种硫化物的保留指数，并可推广到其他类型的汽油馏分中各种硫化物保留指数的计算,为仅能提供硫化物信息的仪器提供了可靠的定性依据。焦化汽油中几种主要硫化物(异丙硫醇、正丙硫醇、正丁硫醇、2-甲基噻吩、3-甲基噻吩、2,4-二甲基噻吩、2,3,4-三甲基噻吩)含量测定值的相对标准偏差均小于5%。当信噪比为3时,测得硫的检测限为0.05 mg/L。研究发现:同其他类型的汽油相比,焦化汽油的硫含量较高且所含硫醇比例明显偏高,2-甲基噻吩和3-甲基噻吩的含量差别较大。该法可为加氢脱硫催化剂和工艺的研究提供数据。

Determination and Distribution of Sulfur Compounds in Coked Gasoline by Gas Chromatography-Sulfur Chemiluminescence Detection

The method for the separation and determination of sulfur compounds in coked gasoline by gas chromatography-sulfur chemiluminescence detection(GC-SCD) was established.Seventy-four sulfur compounds including hydrogen sulfide,mercaptans,sulfides,disulfides,thiophene,alkyl thiophenes,benzothiophene,alkyl benzothiophenes in a coked gasoline sample were identified by standard samples and past identified results.The retention indexes of different sulfur compounds in coked gasoline under programmed temperature condition were calculated based on the retention times of hydrosulfide,ethyl mercaptan,n-propyl mercaptan,thiophene,2-methyl thiophene,2-ethylthiophene,2-propylthiophene,C4-thiophene(tR=40.28 min),benzothiophene,and methylbenzothiophene(tR=58.13 min).The relative standard deviations of the determination results of main sulfur compounds(isopropyl mercaptan,n-propyl mercaptan,n-butyl mercaptan,2-methylthiophene,3-methylthiophene,2,4-dimethylthiophene,2,3,4-trimethylthiophene) in coked gasoline were less than 5%,and the detection limit for sulfur was 0.05 mg/L.The linear range of sulfur was 0.2-400 mg/L for each sulfur compounds(r2=0.999).The contents of sulfur compounds,especially the content of mercaptan,are much more than those in the catalytic gasoline.There is also a big difference in the sulfur contents between 2-methylthiophene and 3-methylthiophene.The data can be useful for the study of hydrodesulfurizing catalyst and industrial process planning.