GC-MS测定润滑油中的烃族组成

按ASTM方法分析油品中的烃族组成,将油品按馏程分为3部分进行分析,ASTM D2789方法分析轻馏分(＜210℃),ASTM D2425方法分析中间馏分(204～343℃),ASTM D2786 D3239方法分析重馏分(205～540℃).本文论述用GC-MS测定润滑油中的烃族组成的过程,并论述测定结果的重复性.     

全二维气相色谱/飞行时间质谱用于柴油组成的研究

将全二维气相色谱法(GC×GC)用于柴油馏分的组成分布研究,建立了两种GC×GC方法,一种用于柴油组成的详细表征,另一种用于柴油族组成的快速分离和定量,两种方法均不需要样品预处理。用前一种方法对柴油馏分中的烃类化合物、主要的含硫化合物与含氮化合物组成进行了研究;对催化裂解柴油中的27种含氮化合物和42种含硫化合物进行了定性;用后一种方法在70 min内即可完成柴油馏分族组成的定量分析,应用所建立的方法测定了4个不同来源的柴油馏分中非芳烃、一环芳烃、二环芳烃、三环芳烃的含量,定量结果与ASTM D2425法     

全二维气相色谱-飞行时间质谱分析焦化柴油中饱和烃的分子组成

建立了全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)分析柴油馏分中饱和烃的分子组成的方法。结合谱库检索、质谱图解析、沸点与分子结构关系和全二维谱图特征,定性(或归类)了焦化柴油饱和烃组分中1057个化合物单体,其中正构烷烃排列规律性最强,一环~三环环烷烃按照极性和沸点的差异呈瓦片状分布在其上方。另外,还准确区分了在一维气相色谱上共流出的正构烷基环己烷和正构烷基环戊烷,以及正构 α 单烯烃。根据质谱采集的总离子流色谱图,采用峰面积归一化法得到了饱和烃组分的碳数分布结果,并将该方法应用于研究不同类型柴油馏分饱和烃的分子组成特点。结果表明,催化裂化和焦化柴油馏分饱和烃组分的化合物类型和分布各不相同。分子组成分析能为油品加工工艺机理的研究提供方法支持。     

全二维气相色谱-质谱分析煤油基吸热型碳氢燃料烃族组成

采用全二维气相色谱-质谱联用（GC×GC-MS）考察了色谱柱系统、程序升温条件和调制周期3个主要因素对样品组分分离结果的影响,建立了煤油基吸热型碳氢燃料烃族组成的定性分析方法,并利用GC×GC-FID通过有效碳数校正因子对烃族组成进行定量。对选取的9种燃料的分析结果表明,该方法对链烷烃和环烷烃的定量结果与标准方法ASTM D2425的结果高度一致,相对误差基本均在±10%以内。利用该方法计算的碳含量结果与元素分析法相比误差均在0.5%以下。该方法无需复杂的前处理,稀释后可直接进样分析,操作简单,而且可直观地看出不同样品之间的差异,为改进燃料的性能提供了必要的分析手段。     

柴油低温流动性改进剂的研制及性能评价 Ⅰ. 低温流动性改进剂对柴油的感受性

在分析胜利石化总厂 0 #柴油和齐鲁石化 0 #柴油的烃族组成、蜡碳分布的基础上 ,进行分子设计 ,研制出一种柴油低温流动性改进剂。它主要由具有一定粘度的三元共聚物组成。实验结果表明 ,这种柴油低温流动性改进剂能十分有效地提高胜利石化总厂 0 #柴油的低温使用性能 ,而胜利石化 0 #柴油对目前国内外其它低温流动性改进剂的感受性较差。     

柴油低温流动性改进剂的研制及性能评价：Ⅰ. 低温流动性改进？…

在分析胜利石化总厂０＃柴油和齐鲁石化０＃柴油的烃族组成、蜡碳分布的基础上,进行分子设计,研制出一种柴油低温流动性改进剂。它主要由具有一定粘度的三元共聚物组成,实验表明,这种柴油低温流动性改进剂能十分有效地提高胜利石化总厂０＃柴油的低温使用性能,而胜利石化０＃柴油对目前国内外其它低温流动性改进剂的感受性较差。     

全二维气相色谱法用于不同石油馏分的族组成分布研究

一直以来采用化学法、色谱法或质谱法等多种方法联用分析不同石油馏分中一 些目标化合物和芳烃含量，但这些方法操作繁琐，迫切需要改进。作者采用全二维 气相色谱方法（GC×GC）研究不同沸程范围的蒸馏汽油、煤油柴油和裂化柴油的烷 烃（P）、烯烃＋环烷烃（O＋N）和1－4环芳烃（A）的族分离新方法。经过对柱系 统进行选择和对色谱条件进行优化，一个GC×GC方法即可实现对不同石油馏分的族 组成分离和目标化合物分离。用标准物对油品中一些特征组分进行定性，并对特征 组分和不同沸程的石油馏分的P，（O＋N），A族组成进行定量和比较，定量结果的 相对标准偏差（RSD）≤2.3。一个GC×GC方法便可完成原来要几个美国测试和材料 协会（ASTM）方法才能完成的任务。     

石油饱和烃分子组成分析方法综述

高效利用石油资源和生产高质量石油产品要求从分子水平认识石油化学组成,而饱和烃作为石油中最主要的一类组分,其分子组成分析是石油化学研究的重要课题.总结了石油饱和烃的分子组成分析方法并简要介绍其应用,主要包括基于气相色谱技术的单体烃分析方法和基于质谱技术的分子/族组成分析方法.针对石油饱和烃的质谱电离技术,总结了各方法的技术优势及存在的问题,对相关技术和方法的发展前景给予展望.     

初馏~523℃馏分油的碳、硫元素模拟蒸馏方法研究

采用气相色谱-原子发射光谱检测器（GC-AED），建立了同时测定减压馏分油（初馏～523℃）中碳、硫收率随沸点变化的色谱模拟蒸馏分析方法．优化了减压馏分油模拟蒸馏的色谱条件和光谱条件．以C5～C40正构烷烃为试样，建立了正构烷烃的沸点与保留时间的校正曲线，进而得到硫色谱图的保留时间与沸点之间的校正曲线．扣除空白实验下碳、硫的基线后，采用自行研制的切片积分软件，得到减压馏分油中碳、硫的收率随沸点变化的关系曲线，并将碳的模拟蒸馏计算结果与ASTMD2887标准方法进行了对比，结果具有较好的一致性．已将该方法用于催化裂化原料中碳、硫分布随沸点变化的研究中．     

石油中间馏分中异构烷烃的分子识别

以石油加氢异构中间馏分及直馏柴油为研究对象,采用气相色谱/质谱联用技术对异构烷烃的分子形态进行了研究。实验表明各碳数异构烷烃组分在毛细管气相色谱柱上表现出明显的按取代基个数簇分离的现象。对异构烷烃的异构程度进行了表征,得到不同取代基个数的异构烷烃的保留指数(RI)定性表;同时根据化合物的质谱断裂规律,参考文献数据并结合碳数及沸点规律,对73种甲基取代的异构烷烃及10种生物标记的化合物单体进行了结构定性,并计算了保留指数。为在分子水平上认识航空煤油及柴油等石油中间馏分中的异构烷烃提供了基础。定性结果表明:在研究的加氢异构中间馏分中,异构烷烃主要由单取代基和二取代基的异构烷烃组成;而在直馏柴油中,单取代基异构烷烃和类异戊二烯类生物标记化合物丰度较高。     

Characterisation of middle-distillates by comprehensive two-dimensional gas chromatography (GC x GC): A powerful alternative for performing various standard analysis of middle-distillates

The detailed characterisation of middle distillates is essential for a better understanding of reactions involved in refining process. Owing to higher resolution power and enhanced sensitivity, comprehensive two-dimensional gas chromatography (GC x GC) is a powerful tool for improving characterisation of petroleum samples. The aim of this paper is to compare GC x GC and various ASTM methods -- gas chromatography (GC), liquid chromatography (LC) and mass spectrometry (MS) -- for group type separation and detailed hydrocarbon analysis. Best features of GC x GC are demonstrated and compared to these techniques in terms of cost, time consumption and accuracy. In particular, a new approach of simulated distillation (SimDis-GC x GC) is proposed: compared to the standard method ASTM D2887 it gives unequal information for better understanding of conversion process.     

Light gasoil of catalytic cracking: A quantitative description of the physical properties by joint use of chromato-mass-spectrometry and molecular dynamics

In the present work, the composition and relative density of light gasoil of catalytic cracking (LGCC) were studied using chromato-mass-spectrometry and its key physical properties were numerically simulated using molecular dynamics. We have studied the distribution of hydrocarbon compounds over narrow fractions of LGCC. We have applied the ASTM D2892-11a standard distillation to find the component composition of LGCC and its narrow fractions obtained from a mixture of West Siberian oils. Molecular dynamics simulations were performed using the GROMOS96 54a7 force field for the ensemble of constant number of particles (N), pressure (P) and temperature (T) (NPT) ensemble under the constant temperature and constant pressure conditions. The topologies of the structures under study were generated by the automated topology builder (ATB) service. Both the chromatographic mass spectrometry experiments and molecular dynamics simulations indicate the contents of aromatic hydrocarbons in LGCC from the mixture of West Siberian oils up to 80 wt%.     

Packed column SFC of gas oils part I: Hydrocarbon group separation using pure carbon dioxide

In this paper, the critical application of the ASTM method to hydrocarbon group separation in gas oils using conventional packed column SFC coupled to FID is described. Resolution of model compounds is studied using a recent commercial apparatus and the chromatographic conditions such as pressure, temperature, and density of the mobile phase and the nature of the stationary phase after FID detection conditions have been selected to give the best sensitivity. Three gas oils differing in composition (ratio arimatic/non-aromatic hydrocarbons)have been selected to evaluate the method for separation of the non-aromatic hydrocarbon group from mono-, di-, and polyaromatic hydrocarbons groups (sub-aromatic groups). The ASTM requiements for this analysis are very easy to obtain in adsorption chromatography. However, in adsorption or normal phase chromatography, SFC results cannot be perfect either for the quantification of aromatic and non-aromatic hydrocarbon fractions because there is still an overlap between the two groups (the separation is better in adsorption chromatography than in normal phase chromatography) or for sub-aromatic fractionation (the separation is better in normal phase chromatography than in adsorption chromatography); combination of both separation techniques only improves the sub-aromatic group fractionation. Thus, further enhancement of resolution for group and sub-group separation is needed.     

Molecular characterization of organically-bound sulfur in crude oils. A feasibility study for the application of Raney Ni desulfurization as a new method to characterize crude oils

Five crude oils with varying sulfur contents (0.1 – 4.7%) were characterized on a molecular level for organically-bound sulfur. Aromatic fractions were analyzed by GC-(MS) and asphaltene and polar fractions were analyzed by flash pyrolysis-GC-(MS). The polar fractions were also desulfurized with Raney Ni and the hydrocarbons formed were analyzed by GC-MS. Major sulfur compounds in the aromatic fractions were identified as alkylbenzo- and alkyldiben-zothiophenes. The flash pyrolyzates of the asphaltene contained alkylthiophenes and alkylbenzothiophenes as major compounds, depending on the thermal maturity of the oil. Generally, the sulfur-rich crude oils contained relatively more sulfur compounds. The flash pyrolyzates of polar fractions contained a variety of sulfur compounds (alkylthiolanes, alkylthianes, terpenoid sulfides, alkylbenzothiophenes) with substantial differences between different crude oils. Raney Ni desulfurization of the polar fraction yielded hydrocarbons dominated by n-alkanes, but isoprenoid alkanes, n-alkylcyclohexanes, mid-chain methylalkanes, tricyclic terpanes, hopanes and steranes were also present. These hydrocarbons show a potential to fingerprint crude oils since their distribution patterns are more characteristic than those of the hydrocarbons present in the saturated hydrocarbon fraction.     

Characterization and quantification of the hydrocarbons fraction of the subcutaneous fresh fat of Iberian pig by off-line combination of high performance liquid chromatography and gas chromatography

Hydrocarbons in fresh subcutaneous fat of Iberian pig have been analyzed by GC-MS after fractionation of the unsaponifiable fraction with a new off-line combination of HPLC and GC method. The new method proposed improves the recovery and simultaneous quantification of terpenic hydrocarbons in comparison to the traditional LC method. When necessary and for identification purposes, selective ion monitoring (SIM) was used as acquisition mode in GC-MS. To determine the position of the double bonds in the unsaturated hydrocarbon chain the dimethyl disulfide derivatives (DMDS) were obtained. To elucidate the structure of the branched 1-alkenes the hydrocarbon fraction was submitted to hydrogenation. Thirty-five compounds have been identified, including n-alkanes, n-alkenes, branched (n-1,n-2-dimethyl-1-alkenes) and terpenic hydrocarbons, being the most abundant n-alkenes and n-alkanes of even chain of n-C12-n-C26. Besides the hydrocarbons already described in bibliography, a new diterpenic hydrocarbon, ent-kaurene, have been identified for the first time. The compound reported as Neophytadiene by other authors, has been identified as a 20 atoms hydrocarbon with two double bonds, the 7,11,15-trimethyl-heptadeca-1,4-diene.     

Multidimensional gas chromatographic determination of naphthenes, paraffins, olefins, and aromatics in reformed gasolines

Increasing demand for gasoline, changing regulations concerning the reduction of environmental impact, and new refining technologies have led to the refinement of its composition. Nowadays, gasoline is a complex mixture of different fractions deriving from processes of reforming, cracking, isomerization, and alkylation, with the addition of both oxygenated compounds and butanes. There are regulations governing the mixing of various fractions and it is necessary to analyse the composition of these fractions to ensure that the final composition of commercial gasoline satisfies the required specifications. Moreover, analysis of the composition of each fraction enables the technological process of the fraction examined to be modified as appropriate. In this work some reformed gasolines were analysed by multidimensional gas chromatography. This technique allows good separation of the hydrocarbon types in a single analysis and gives the carbon number distribution within each hydrocarbon type.     

Detailed Hydrocarbon Class Composition Analysis and Trace Level BTEX Estimation in Raffinate Column Bottom (RCB) Using GC×GC–TOFMS

A two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC–TOFMS) method was developed for the hydrocarbon class composition analysis and benzene, toluene, ethylbenzene, and xylene (BTEX) estimation of raffinate column bottom (RCB), which is generated as a by-product from linear alkyl benzene (LAB) plants. The molecular level characterization of RCB is important to generate value-added products for the petrochemical industry. GC×GC–TOFMS was found to be an excellent tool for estimation of hydrocarbon class composition (paraffins, naphthenes, monoaromatics, diaromatics, and polyaromatic hydrocarbons) and trace level BTEX in a single run. The hydrocarbon class composition was validated with the standard method based on HPLC (ASTM D6591) and good correlation was obtained. Finally, RCB is anticipated to be a useful nonhazardous safe by-product which could be used further for generating added value.     

Multidimensional Gas Chromatography–Mass Spectrometry Method for Fingerprinting Polycyclic Aromatic Hydrocarbons and Their Alkyl-Homologs in Crude Oil

The composition of polycyclic aromatic hydrocarbons in crude oil is usually too complex to use standard capillary gas chromatography to separate all of the components. In this study, a multidimensional gas chromatography–mass spectrometry (GC-MS) technique was used to analyze polycyclic aromatic hydrocarbon fractions of crude oil collected from the Dongying oil field in the Bohai Sea. A DB-17MS column (30?m?×?0.25?mm?×?0.25?µm) was used as a prefractionating column and only selected heart-cuts were transferred to the second chromatographic dimension (HP-5MS, 15?m?×?0.25?mm?×?0.25?µm) by a pressure-adjusted continual flow-type switching device for quantification of the polycyclic aromatic hydrocarbons. The chromatographic elements and parameters, such as detector selection and column combinations, were optimized. Naphthalene, phenanthrene, fluorene, dibenzothiophene, chrysene, and their C₁–C₄ alkyl homologs were identified. The profile of the polycyclic aromatic hydrocarbons obtained using the multidimensional GC-MS method was compared with the results obtained by traditional one-dimensional GC-MS.