Heat Capacity of a Synthetic Distillation Cut+n-Hexane System under Pressure

Isobaric heat capacities of synthetic mixtures were determined up to 40 MPa with a modified C-80 Setaram calorimeter equipped with cells designed for high pressures. The system investigated was a pseudo-binary hexane+synthetic cut, the latter consisting of compounds of the three chemical families that occur most frequently in natural effluents (paraffins, naphthenes and aromatics). The additional knowledge of density vs. pressure and temperature affords the specific heat γ ratio.     

全二维气相色谱用于轻质石油馏分中芳烃含量的测定

建立了采用全二维气相色谱(GC×GC)技术一次进样完成轻质石油馏分中非芳烃、一环芳烃和二环芳烃的分离、定性 和定量。通过对柱系统的选择和色谱条件的优化,实现了一次全二维气相色谱分析即完成轻质石油馏分的族组成分离以及 目标化合物的分离。方法的加标回收率为89.5%～106.1%;样品中各组分含量重复测定的相对标准偏差均不大于5.8%,能 够满足样品测定的精密度和准确性要求,且完成1次分析最多只需要30 min。     

Liquid–liquid equilibrium calculations for methanol–gasoline blends using continuous thermodynamics

This work presents the application of continuous thermodynamics to investigate the limited miscibility of methanol–gasoline blends. To predict the liquid–liquid equilibrium of these systems, the Gaussian distribution function was used to represent the composition of paraffins in the gasoline. The naphthenes and aromatics were represented by model compounds. A model has been developed using three different continuous versions of the UNIFAC model. Methanol is an associating component, and association affects phase equilibria. Therefore, the CONTAS (continuous thermodynamics of associating systems) model based on the Flory–Huggins equation, for multicomponent methanol–gasoline blends has also been investigated. The predicted results including the cloud point curve, shadow curve and phase separation data have been compared with experimental data and good agreement was found for the two UNIFAC and CONTAS models.     

重整生成汽油样品中烃的类别分析

用气相色谱以程序升温方式分析了重整生成汽油,并将各组分升温保留时间转换为恒温保留指数。以各组分在ＯＶ－１和ＳＥ－５４固定相上,同一柱温下的保留指数差及在各柱上的温度系数为三因素进行斜交因子分析和本征矢量旋转,给出了重整生成汽油样品中烷烃、烯烃、环烷烃、芳烃值,经气相色谱－质谱分析验证了结果的正确性,为重整成成汽油样品中烃的类别分析提供了一种新方法。     

全二维气相色谱-飞行时间质谱对催化裂化汽油的定性与定量分析

采用全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)对催化裂化汽油全馏分进行了定性与定量分析,建立了相应的分析方法.结果表明,汽油族组成中的烷烃、烯烃、环烷烃、芳烃在全二维点阵谱图中呈分区域、带状的分布特点.GC×GC-TOF MS根据催化裂化汽油组分内分子的沸点及极性差异对其进行两个维度分离,极大地避免了普通色谱法分析过程中沸点相似化合物共流的弊端,实现催化裂化汽油组分的精确分离和准确定性分析.通过引入响应因子,修正了不同性质的烃类在电离源上电离效率的差异,使得TOF对催化裂化汽油族组成的定量结果与普通气相色谱法的定量结果的相关性较好,且应用GC×GC-TOF MS方法获得了催化裂化汽油更为精确的族组成信息.GC×GC-TOF MS为催化裂化汽油精确表征提供了一种有效方法.     

Determination of alcohols in gasoline blends using a multi-dimensional switching system

Methanol, 2-Me-propanol-2, propanol-2, benzene, toluene and xylenes in gasoline blends were determined using a valveless multi-dimensional switching system (MDSS) with two packed columns and temperature programming. Compounds of interest, interfering with paraffins and naphthenes, were in a sequence of four heart cuts transferred onto the second column. The resulting baseline separation enabled precise quantitative measurement within a short analysis time. Instrument settings, times of switching and integration parameters were stored in an instrument memory file (user table) and thus high precision in the measurements was achieved.     

判别分析用于烃类化合物分类及汽油样品的族组成分析

研究了判别分析用于烃类化合物分类的可行性，以198个烃类化合物在BD－1和BD－5固定相上同一柱温下的保留指数差及其在各柱上的温度系数为判别变量，成功地建立了烷烃、环烷烃、芳烃和烯烃的判别函数，以此对裂化汽油，重整生成汽油、石脑油和蒸馏常顶汽油进行了族组成分析，经气相色谱－质谱分析验证了结果的正确性，为汽油产品的族组成分析提供了一种新的方法。     

Measurement and prediction of phase equilibria in the extraction of aromatics from naphtha reformate by tetraethylene glycol

The extraction of aromatics from naphtha reformate was carried out by the solvent tetraethylene glycol at six temperatures and three solvent to feed ratios. The concentrations of paraffins, naphthenes and aromatics in the extract and raffinate phase were measured and compared to values predicted by the UNIFAC group contribution model. It was shown that the UNIFAC model is capable of predicting the concentrations in this multicomponent system with an overall RMSD of 1.27 mol.%.     

Characterization of military fog oil by comprehensive two-dimensional gas chromatography

The most commonly used military fog oil is characterized by comprehensive two-dimensional gas chromatography (GC×GC) coupled to either Flame Ionization Detection (FID) or Time-of-Flight Mass Spectrometric Detection (TOFMS) to advance the knowledge regarding the complete chemical makeup of this complex matrix. Two different GC×GC column sets were investigated, one employing a non-polar column combined with a shape selective column and the other an inverse column set (medium-polar/non-polar). The inverse set maximizes the use of the two-dimensional separation space and segregates aliphatic from aromatic fractions. The shape selective column best separates individual polycyclic aromatic hydrocarbons (PAHs) from the bulk oil. The results reveal that fog oil (FO) is composed mainly of aliphatic compounds ranging from C₁₀ to C₃₀, where naphthenes comprise the major fraction. Although many different species of aromatics are present, they constitute only a minor fraction in this oil, and no conjugated PAHs are found. The composition of chemically similar aliphatic constituents limits the analytical power of silica gel fractionation and GC–MS analysis to characterize FO. Among the aliphatic compounds identified are alkanes, cyclohexanes, hexahydroindanes, decalins, adamantanes, and bicyclohexane. The aromatic fraction is composed of alkylbenzene compounds, indanes, tetrahydronaphthalenes, partially hydrogenated PAHs, biphenyls, dibenzofurans and dibenzothiophenes. This work represents the best characterization of military fog oil to date. As the characterization process shows, information on such complex samples can only be parsed using a combination of sample preprocessing steps, multiple detection schemes, and an intelligent selection of column chemistries.     

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。     

吸热型碳氢燃料的核磁共振和色谱/质谱分析及热力学性质

测定两种吸热型碳氢燃料的^1H和^13C NMR谱,从NMR等实验数据计算得到平均分子结构参数。以基团贡献法为桥梁,总结定量结构—性能关系,从NMR结构信息预测了燃料的蒸发焓和燃烧焓,与热力学实验结果吻合良好。用GC/MS分析燃料的化学组成,检出主要由脂肪烃、芳烃和环烷烃3类构成的60余种烃类化合物,为吸热型碳氢燃料的结构和特性表征以及燃料的开发提供重要信息。     

Hydrocarbon type analysis by gas chromatograph using a single capillary column and a multi-column valve system

Summary Two different gas chromatographic methods are used for the determination of hydrocarbon type distribution in naphtha and gasoline samples with final boiling points up to 275 °C. The methods are based either on a single capillary column or on a valve-switched packed column system. Both methods give extensive information on paraffins, olefins, naphthenes and aromatics in total as well as by carbon-number. In each case the analysis is fully automated with a computer controlling the entire analysis from injection to results presentation. The advantages and limitations of both methods are discussed.Presented at the 14th International Symposium on Chromatography London, September, 1982     

Formation of aromatics during the pyrolysis of oligocyclic naphthenes: Indications for a mechanistic alternative

It is known that aromatics are formed in much higher yields in the pyrolysis of di- and oligocyclic naphthenes than in that of alkanes and monocyclic naphthenes. To study the mechanisms of the formation of aromatics from naphthenes, the thermal decomposition of dicyclohexyl, decalin, dodecahydrofluorene, tetradecahydroanthracene, hexadecahydropyrene and [9,10-¹⁴C]tetradecahydroanthracene was studied in different laboratory tubular furnaces from 800 to 850°C. The reaction products were analysed by conventional and radio gas chromatography. As an important consequence of the results, a new hypothesis for the formation of aromatics via acyclic, multiply unsaturated hydrocarbon species as precursors is presented.     

An automatic PNA analyser for the under 200°C fraction contained in a higher boiling product

Summary We present a modified circuit for the PNA-analyser, which allows analysis for paraffins, naphthenes and aromatics in the under 200°C fraction of a sample having a final boiling point above 200°C. The modified separation scheme gives, in addition, improved type separation. By the introduction of adapted instrumentation the analyser has been suited to fully automated serial analysis. The new concept will eventually be commercialized.A glossary of abbreviations has been included at the end of this paper.     

Comprehensive two-dimensional gas chromatography for enhanced analysis of naphthas: new column combination involving permethylated cyclodextrin in the second dimension

A new column association using comprehensive two-dimensional gas chromatography for the detailed molecular analysis of hydrocarbon mixtures is reported in this paper. In order to compare the impact of two different secondary columns, a novel column combination relying on a GC x 2GC system was used. This system is based on a non-polar first column (PONA) combined with both a permethylated beta-cyclodextrin (beta-Dex 120) stationary phase and a polysilphenylensiloxane (BPX 50) in the second dimension. Compared to BPX 50 stationary phase, the implementation of beta-cyclodextrin columns as the second dimension was found to improve the resolution between paraffins and naphthenes in the naphtha range but not in the middle distillate range. Attempts to improve the results and to understand the interaction mechanism remained unsuccessful. Therefore, the benefits of the beta-Dex 120-column are only demonstrated on heavy naphtha cut for the quantitation of hydrocarbons.     

Multidimensional gas chromatography for the detailed PIONA analysis of heavy naphtha: hyphenation of an olefin trap to comprehensive two-dimensional gas chromatography

A multidimensional method providing the composition of a heavy naphtha in paraffins, isoparaffins, olefins, naphthenes, and aromatics (PIONA) in the C8-C14 range is presented. The analytical set-up consists in a silver modified silica olefin trap on-line coupled to comprehensive two-dimensional gas chromatography (GC x GC). In this configuration, hydrocarbons are separated, in gaseous state, in two fractions, saturate and unsaturate, each fraction being subsequently analysed by GC or by GC x GC. The resolution between saturates and olefins was found to be improved compared to a single GC x GC run. The characterisation of the olefin trap highlights the benefits and the limits related to the use of that stationary phase as a double bond selective fractionation medium.     

催化裂化汽油中含硫化合物的分离氧化脱硫研究

以负载氧化铜的氧化铝层析柱对催化裂化(FCC)汽油全馏分进行分离,使其中的烷烃、烯烃与芳烃、含硫化合物分离成极性不同的两组,含硫化合物在芳烃组分中得以分离富集。分离后对芳烃组分中的含硫化合物进行氧化,脱硫率达72%。氧化后的芳烃组分与分离出来的烷烃、烯烃组分混兑,可使FCC汽油的总脱硫率达71·3%。     

An extended saturated liquid density equation

The recently developed saturated liquid density correlation of Iglesias-Silva and Hall for halogenated paraffins is extended to other classes of compounds involving paraffins, cycloparaffins, olefins, diolefins, cyclic-olefins, aromatics, alcohols, ethers, liquefied inorganic gases, and others. The two adjustable parameters of the correlation are optimized and reported for 126 compounds. The average error for 5377 experimental data points was 0.27%. The correlation is extended to multicomponent mixtures. A set of mixing rules is proposed. The correlation with this set of mixing rules is used to predict the saturated liquid density of 86 multicomponent systems consisting of LNG, heavy hydrocarbons, CO₂, H₂S, alcohols and halogenated paraffins. The average of error for 1378 experimental data points was 1.03% with 0 bias with respect to experimental data. These values compare well with the values from well-known correlations. For polar compounds or multicomponent systems containing polar compounds, the computation of saturated liquid density by this correlation shows superiority with respect to the other correlations.     

Synthesis and some aspects of the formation mechanism of carbon structures under hydrothermal conditions

The formation of carbon structures upon the reactions of organic compounds with strong mineral acids under hydrothermal conditions was studied. The reactions were found to give amorphous carbon, microcrystalline graphite, nanodiamonds, diamond-like carbon, diamonds, C₆₀ and C₇₀ fullerenes, and carbolite. Hydrocarbons of various compositions including aromatics and naphthenes were detected among the reaction products. A possible mechanism of the formation of carbon structures with sp ² bond hybridization under hydrothermal conditions was proposed.