Determination of sulphur heterocycles in selected synfuels

A fractionation method for isolating the polycyclic aromatic sulphur heterocycles from complex mixtures of polycyclic aromatic compounds was evaluated with respect to recovery for selected standard compounds. It was found that recovery varied from 0 to 70% depending on the structure of the compound. Although quantitative recovery for all components was not obtained, isolation of the sulphur heterocycle fractions has allowed the identification of many new sulphur compounds previously not identified in coal liquids and shale oils. Capillary column gas chromatography with flame photometric detection and mass spectrometry were used for the identification of individual sulphur heterocycles.     

The relation between polycyclic aromatic compounds in diesel fuels and exhaust particulates

The polynuclear aromatic compound fractions (PAC) separated by column chromatography from five diesel fuels, a gas oil and sample of kerosene were analysed by capillary column gas chromatography with simultaneous parallel triple detection. The principal polynuclear aromatic hydrocarbons of the fuels are naphthalene, fluorene and phenanthrene and their alkyl derivatives; mutagenic compounds are present in significant concentrations. The principal polynuclear aromatic nitrogen and sulphur compounds of diesel fuel are carbazole and dibenzothiophene and their alkyl derivatives. The PAC of diesel exhaust particulates are similar to those of the fuel, and follow the overall trend of particulate emission with engine load. The 2 to 4-ring PAC in the exhaust are primarily unburnt fuel components. Between 0.2 and 1.0 wt% of these fuel PAC survive the combustion process and comprise a significant concentration of mutagenic compounds in the particulate.     

Sulphur heterocycles in coal-derived products: Relation between structure and abundance

Sulphur heterocycles in a coal tar and in a coal liquid vacuum residue were isolated by ligand exchange chromatography using PdCl₂ on silica gel. Subsequent fractions were analysed by capillary column gas chromatography and gas chromatography-mass spectrometry. Two new selective stationary phases (a smectic liquid-crystalline polysiloxane and a biphenyl polysiloxane), as well as a methylpolysiloxane, were used to resolve the numerous isomers. All major sulphur heterocycles with 3–6 rings were identified by comparison of retention times of mixture components with those of standard reference compounds. The structures and relative abundances of the major sulphur heterocycles were analogous to those of the major polycyclic aromatic hydrocarbons in the same or similar samples.     

Determination and mutagenic activity of nitrogen-containing thiophenic compounds in coal-derived products

Polycyclic aromatic compounds containing both nitrogen and sulphur heteroatoms in aromatic rings were determined in a coal-derived liquid and a coal tar by capillary column gas chromatography and gas chromatography-mass spectrometry. G.c. with a flame photometric detector was used to analyse the nitrogen-containing polycyclic aromatic compound fraction obtained by adsorption chromatography on neutral alumina. The four possible isomers of the azadibenzothiophenes, and various other azathiophenic compounds, were positively identified by comparison with retention data of newly synthesized standard compounds. The aminodibenzothiophenes were the major nitrogen/sulphur-containing heterocycles in the coal liquid, while the azathiophenic compounds were the major ones in the coal tar. The differences between the two coal-derived products were related to the reaction conditions during their production. The four isomers of the azadibenzothiophenes were assayed for mutagenicity using the Ames test and compared with the mutagenicities previously reported for the aminodibenzothiophenes. It was found that the azadibenzothiophenes were not mutagenic, as opposed to the aminodibenzothiophenes.     

Polycyclic Aromatic Sulfur Heterocycles in Desulfurized Diesel Fuels and Their Separation on a Novel Palladium(II)-Complex Stationary Phase

The lowering of the legal concentration of sulfur in fuels (in the European Union from 150 ppm at present to 50 ppm in 2004) not only affects the concentration but also the pattern of the polycyclic aromatic sulfur heterocycles (PASH) in the fuels. This pattern was studied for 12 diesel samples, most of which have been desulfurized. A separation of the PASHs and the polycyclic aromatic hydrocarbons becomes necessary at such sulfur levels. An efficient liquid chromatographic method for this is presented and involves a Pd(II)-containing complex based on 2-amino-1-cyclopentene-1-dithiocarboxylate covalently bonded to silica. The resultant PASH fraction can be analyzed by gas chromatography/flameionization detection.     

Determination of PAHs in Combustion-Related Samples and in SRM 1597, Complex Mixture of PAHs from Coal Tar

Three types of combustion sample extracts, smokeless coal, smoky coal, and wood, were analyzed for a range of polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic sulfur heterocycles (PASH). Standard Reference Material (SRM) 1597, Complex Mixture of PAHs from Coal Tar, was also analyzed as a control sample and for the determination of a larger number of PAHs relative to those determined previously. Target analytes included many alkyl-substituted PAHs such as dimethylphenanthrenes, methylfluoranthenes, and methylpyrenes. The analytical methods included sample clean-up and the selection of specific stationary phases to accomplish unique separations of PAHs. Clean-up involved the use of normal-phase liquid chromatographic isolation of PAHs based on the number of aromatic carbons and a total PAH fraction, PAHs in the resulting fractions were separated by gas chromatography using two stationary phases with different selectivities and analyzed using mass spectrometry. These methods are discussed below and results are presented with an emphasis on the relative concentrations and distribution of PAHs in the combustion samples.     

Aromatic and hetero-aromatic compositional changes during catalytic hydrotreatment of shale oil

Oil shale from the Kimmeridge Clay, of Jurassic age from the UK was pyrolysed in a 5 kg fixed bed reactor at 525°C in a nitrogen atmosphere. The derived shale oil was then hydrotreated at 15.0 Mpa pressure and 400°C in a stirred reactor with a nickel–molybdenum (Ni–Mo) catalyst and residence times from 8 to 56 h. The shale oils were analysed for polycyclic aromatic hydrocarbons (PAH) and for nitrogen-PAH (PANH) and sulphur-PAH (PASH), before and after hydrotreatment. The results showed that generally the higher molecular weight three and four ring PAH decreased with increasing hydrotreatment time, however, single ring aromatic compounds and two ring PAH were increased. Nitrogen and sulphur containing PAH were significantly reduced in concentration in the oils with increasing hydrotreatment time to reach negligible concentrations after 56 h. The reduction in PANH and PASH coincided with a reduction in the overall nitrogen and sulphur contents of the oils.     

重整生成油C_8馏分中芳烯烃的分析

采用毛细管气相色谱-氢火焰离子化检测器(CGC-FID)和气相色谱-质谱法(CGC/MS)分析了重整生成油C8馏分中的芳烯烃。实验使用HP-FFAP毛细管色谱柱(50m×0.32mm×0.50μm)和ATTM-WAX毛细管色谱柱(50m×0.32mm×0.30μm),根据烃类化合物在这两种色谱柱上的保留规律,用CGC/MS联用技术和UOP方法744-06以及标准样品相结合的方法对重整生成油C8馏分中的芳烯烃进行了定性定量分析,从12O多种组分中鉴定出18种烯烃,对其中的15种烯烃组分进行了定量分析,对其它3种烯烃组分进行了半定量分析。本法操作简单、重复性好,适用于重整生成油C8馏分和二甲苯塔塔顶液的烯烃检测,也可用于芳烃厂同类产品质量控制分析。     

Characterization of pyrolysis tars from Canadian coals

Tars produced by rapid pyrolysis of several Canadian coals have been characterized. Raw tars were separated into solvent fractions which were analysed by a combination of PONA separation by high-performance liquid chromatography, high-resolution capillary gas chromatography and chromatography-mass spectrometry. The alkane-alkene pairs and poly nuclear aromatics found in hexane and benzene fractions are reported for four coals pyrolysed under a range of conditions. The predominance of C₈ to C_14–18 alkane-alkene pairs together with alkyl-substituted benzenes and naphthalenes in the hexane-soluble oils, and three-to five-membered ring aromatics in the benzene-soluble asphaltenes from bituminous coal tars was established. Effects of pyrolysis temperature on aromatic homologues and key nitrogen, sulphur and oxygen heterocyclic homologues are shown.     

气相色谱法测定氯化苯的纯度

介绍采用氢火焰检测器的气相色谱法测定氯化苯产品中的氯化苯、苯及多氯苯含量的方法,并比较了采用热导池检测器的气相色谱法分析与采用毛细管色谱柱分析两者的效果.     

Characterization of polynuclear aromatic hydrocarbons in bitumen,heavy oil fractions boiling above 350 °C by g.c.-m.s.

The separation and characterization of polynuclear aromatic hydrocarbons of five fractions of bitumen, heavy oils and synthetic fuels boiling > 350 °C were performed using a combination of Chromatographic techniques. The polynuclear aromatic hydrocarbon fractions were obtained by liquid-solid chromatography and prior to the high performance liquid chromatography and gas chromatography/mass spectrometry techniques, the fractions were subjected to an acid/base extraction procedure to remove polar material. In total, 97 polynuclear aromatic hydrocarbons were tentatively identified by a correlation of their mass spectra and retention indices with those of 25 model polynuclear aromatic compounds.     

Analysis of polycyclic aromatic sulfur heterocycles in Egyptian petroleum condensate and volatile oils by gas chromatography with atomic emission detection

Eight Egyptian petroleum condensates and two volatile oils were analyzed by gas chromatography. The condensate oils range in color from colorless to yellow and brown. The samples are composed mainly of saturates hydrocarbons (C₃ to C₃₅). The polycyclic aromatic sulfur heterocycles (PASH) were isolated through use of a silica bonded palladium(II)-complex and their distribution investigated by gas chromatography (GC) with atomic emission detection (AED) in the sulfur-selective mode. The condensate oils show distinctly different distributions of the PASHs, some containing mainly benzothiophenes, and others both benzo- and dibenzothiophenes and a third group in which the dibenzothiophenes strongly dominate. The alkyl substituted sulfur compounds are quantified. The distribution patterns of the PASHs are correlated to the type of reservoir source rocks.     

Effects of oxygenate concentration on species mole fractions in premixed n-heptane flames

Atmospheric pressure, laminar, premixed, fuel-rich flames of n-heptane/oxygen/argon and n-heptane/oxygenate/oxygen/argon were studied at an equivalence ratio of 1.97 to determine the effects of oxygenate concentration on species mole fractions. The oxygen weight percents in n-heptane/oxygenate mixtures were 2.7 and 3.4. Three different fuel oxygenates (i.e. MTBE, methanol, and ethanol) were tested. A heated quartz micro-probe coupled to an on-line gas chromatography/mass spectrometry has been used to establish the identities and absolute concentrations of stable major, minor, and trace species by the direct analysis of samples, withdrawn from the flames. The oxygenate addition has increased the maximum flame temperatures and reduced the mole fractions of CO, low-molecular-weight hydrocarbons, aromatics, and polycyclic aromatic hydrocarbons. The reduction in mole fractions of aromatic and polycyclic aromatic hydrocarbon species by an increase in oxygenate concentration was more significant.     

Thermal reactions of methyl linoleate. I. Heating conditions,isolation techniques,biological studies and chemical changes

Methyl linoleate, diluted with an equal weight of methyl laurate, was heated without exclusion of air at 200C for 200 hours. The reaction mixture was separated by means of molecular distillation, urea adduction, column chromatography, and gas chromatography. Cyclic and aromatic materials were detected in the nonurea adductable monomer fractions. The dimer was separated into polar and nonpolar fractions. Analytical data for the nonpolar dimer are consistent with a cyclic Diels-Alder product. Bioassays showed the nonadductable monomer, the polar dimer, and a fraction of intermediate boiling point to be toxic when administered to weanling male rats. Urea-adductable fractions, nonpolar dimer, and polymer were not toxic. The concentrations of the toxic components were so low that the heated linoleate, before fractionation but after removal of the laurate, was not toxic.     

0.8%四氟菊酯驱蚊药液的毛细管柱气相色谱分析

描述了用毛细管气相色谱对0．8%四氟菊酯驱蚊药液的定量分析方法。样品溶于含内标物邻苯二甲酸二正戊酯的异丙醇中，用DB-1毛细管分离并用带有火焰离子化检测器的气相色谱测定四氟菊酯。气化室温度：230℃；检测器温度：300℃；柱箱温度：起始温度100℃；升温速率15℃／min；终止温度28℃，保持时间10min。方法的变异系数为6．4%，回收率在92%～108%之间。     

光离子化气相色谱法对空气中挥发性有机物的测定研究

采用光离子化气相色谱仪新技术测定了室内空气中典型的挥发性有机化合物。研究了气相色谱仪柱温、载气压力对色谱峰的分辨率、保留时间和强度的影响,确定了光离子化气相色谱法测试苯系物的最佳条件,通过与传统FID气相色谱法的比对,结果表明:光离子化气相色谱法测定苯系物的灵敏度(检出限)比氢火焰离子化气相色谱法优于100倍以上,前者的分辨率也比后者的高。     

Bituminous impurity in the elemental sulphur from the Mishraq deposit

The bituminous impurity incorporated with the elemental sulphur in the Mishraq deposit was separated by solvent extraction. The extract was further fractionated by column chromatography and the fractions were studied spectroscopically (i.r. u.v., and p.m.r.) The observation that the bituminous material is basically asphaltic (ca. 80% of the total weight, precipitated by straight-chain pentane) with no detection of light components, coupled with the p.m.r. results on carbon type distribution, may add support to the existing theories about the origin of elemental sulphur in the Mishraq region. Elemental analysis of bitumen samples isolated from Frasch sulphur when compared with those isolated from borehole samples using identical isolation techniques may indicate that a reaction between elemental sulphur and the bituminous impurity is taking place under the thermal conditions of the Frasch Process.     

Chemical composition and toxicological activity of liquefaction materials derived from different feed coal ranks

Samples of recycle solvent from the bottoms recycle mode of the EDS direct coal liquefaction process using bituminous, sub-bituminous, and lignite coal feeds were chemically characterized and tested for toxicological response. The H-Coal heavy fuel oils derived from bituminous and sub-bituminous coals were also analyzed. Chemical methods of analysis included adsorption column chromatography, high-resolution gas chromatography, gas chromatography/mass spectrometry, and low-voltage probe-inlet mass spectrometry. The toxicological activity of selected samples was evaluated using the standard histidine reversion microbial mutagenicity assay, an initiation/promotion assay for mouse-skin tumorigenicity, and a static bioassay with Daphnia magna for aquatic toxicity of the water-soluble fractions. Both materials derived from the bituminous coals had the following chemical characteristics as compared to their sub-bituminous coal and/or lignite-derived counterparts: higher concentrations of polycyclic aromatic hydrocarbons (PAH), nitrogen-containing polycyclic aromatic compounds, and hydroxy-substituted PAH; lower concentrations of aliphatic hydrocarbons; and a generally increased molecular weight distribution of approximately ten atomic mass units. Toxicological testing indicated a general trend of increased biological activity of the coal liquefaction products with increasing feed coal rank.     

Lipids in sea water

Acidified and filtered sea water samples which were extracted with petroleum ether and ethyl acetate have been shown to contain a variety of lipid compounds in trace amounts. Concentrations of these solvent-soluble substances ranged from 0.5 to 6.0 mg/liter, the lower concentrations being found in offshore waters. The solvent extracts of the sea water were separated into eight lipid classes by column chromatography on silicic acid. The fractions eluted with solvents of increasing polarity were characterized by thin-layer chromatography, infrared and ultraviolet absorption and gas chromatography. These techniques revealed a complex mixture of alkanes, alkenes, fatty acids, steroids, phospholipids and many as yet unidentified components. Twenty to thirty alkanes were present as indicated by gas chromatography. No aromatic hydrocarbons were detected. Chromatography of the methyl esters of the fatty acids indicated the presence of acids with chain lengths varying from 14 to 22 carbons, both saturated and unsaturated. In many samples the unsaturated fatty acids containing 18 to 22 carbons predominated. The lipid components varied somewhat in composition as well as concentration from location to location and with season and depth.     

高效微型液相色谱与高温气相色谱联合测定润滑油族组成

采用填充毛细管液相色谱 (PC -HPLC)与高温毛细管气相色谱 (CGC)在线联用技术分析润滑油全组分。PC -HPLC柱 ( 0 .32mmi.d .)用于样品族分离 (烷烃、单环芳烃、双环芳烃、三环芳烃和胶质 )。经PC -HPLC分离后的各族组分被依次存放在多位储存接口内 ,然后分别转入GC作单个族组分的定量分析。该方法是解剖进口润滑油基础油及新产品开发中强有力的分析手段。