固相萃取-气相色谱-质谱法测定费-托合成油中间馏分的烃类组成及碳数分布

采用SiO₂/Ag-Al₂O₃双柱固相萃取技术将费-托合成油中间馏分分离为饱和烃、烯烃、芳烃、氧化物等组分，利用气相色谱-质谱/氢火焰离子化检测器（GC-MS/FID）和气相色谱-场电离-飞行时间质谱（GC-FI TOF MS）表征各组分的类型和碳数分布。结果表明：低温费-托合成油中间馏分以正构烷烃、正构α-烯烃、正构醇为主，分别为41.0%，30.3%，8.8%，其他化合物基本为异构化合物；高温费-托合成油中间馏分组成复杂，正构化合物含量减少，异构化合物含量明显增加，其饱和烃中存在环烷烃，烯烃中出现双烯烃、三烯烃或环烯烃，芳烃以单环芳烃为主。

DETERMINATION OF HYDROCARBON COMPOSITION AND CARBON NUMBER DISTRIBUTION IN THE MIDDLE FRACTION OF FISCHER-TROPSCH SYNTHETIC OIL BY SOLID PHASE EXTRACTION AND GAS CHROMATOGRAPHY-MASS SPECTROMETRY

SiO₂/Ag-Al₂O₃ double column solid phase extraction was used to separate the middle fraction of Fischer-Tropsch synthetic oil（F-T oil） into saturated hydrocarbons, olefins, aromatics and oxides etc. , and gas chromatography-mass spectrometry/hydrogen flame ionzation detector (GC-MS/FID) and gas chromatography field ionization time of flight mass spectrometry (GC-FI TOF MS) were used to characterize the type and carbon number distribution of each component. The results show that the middle fraction of low temperature F-T oil is mainly composed of n-alkanes, α-olefins and normal alcohols, whose contents are 41.0%, 30.3% and 8.8%, respectively, and other compounds are basically isomeric compounds. The middle fraction of high temperature F-T oil is complex, and the normal compounds are reduced while the proportions of isomeric compounds are significantly increased. Cycloalkanes were found in saturated hydrocarbons, dienes, trienes or cycloalkenes were found in olefins, and monocyclic aromatics were main aromatics.