Charakterisierung eines schweren Kohleverflüssigungsproduktes durch kombinierte Hochleistungsflüssigkeitschromatographie/Massenspektrometrie

Zusammenfassung Ein Recycleöl wurde semipräparativ auf einer Tetrachlorphthalimidopropylsilan-modifizierten Säule hochleistungsflüssigkeitschromatographisch in 23 Fraktionen getrennt. Zur Identifizierung der Hauptkomponenten wurden die Fraktionen mit einer einfachen Präparationstechnik in das Massenspektrometer eingebracht und die Molekülionenspektren unter Benutzung der Low Voltage-Technik gemessen. Vorteilhaft für die Charakterisierung hochsiedender technischer Gemische ist die Tatsache, daß die chromatographische Trennung streng nach der Anzahl der aromatischen Ringe im Molekül erfolgt, weitgehend unabhängig von der Alkylsubstitution.

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Characterization of a heavy coal liquefaction product by combined high-performance liquid chromatography/mass spectrometry

Summary A recycle-oil was separated on a semi-preparative scale into 23 fractions by means of HPLC with a tetrachlorophthalimidopropylsilane-modified column. Mass spectrometry enabled a more or less complete identification of the main components. For this, the fractions were introduced into the mass spectrometer by a simple preparation technique, followed by measurement of the molecule ion spectra by the low voltage technique. An advantage of HPLC for the characterization of high-boiling oil mixtures is that separation takes place almost exclusively accoding to the number of aromatic rings in the molecule and is largely independent of the degree of alkylation.

     

Catalytic hydrogenation of benzo(a) and benzo(e) pyrenes. Analysis of the hydrogenated products by charge transfer chromatography and HPLC on amino bonded phase

Summary Hydroaromatics (partially hydrogenated polycyclic aromatic hydrocarbons) generated in the course of the process play an important role in the catalytic hydroliquefaction of coal. A difficult analytical task is to identify and to quantify these hydroaromatics among the preponderant polycyclic aromatic hydrocarbons. Generally speaking, the method carried out uses the specific separation of hydroaromatic by charge transfer chromatography. Structural identification is effected by using gas chromatography, alone or coupled with mass spectrometry, and HPLC on amino bonded phase with UV detection.As an aid to obtaining the standard compounds that are essential in that work, this paper describes the application of the above analytical procedure to the catalytic hydrogenation products (RhCl₃/NaBH₄ and Pd/C) of benzo(a) and benzo(e)pyrenes.     

Cellulose liquefaction in acidified ethylene glycol

Wood pulp cellulose was used in a study of its catalyzed liquefaction in the presence of ethylene glycol, p-toluene sulfonic acid monohydrate or sulphuric acid being the catalysts. For this study, microcrystalline cellulose, Whatman filter paper no. 1 and cotton linters with molar masses of 76,000, 699,000 and 1,910,000 g mol⁻¹, respectively were used. This liquefaction was studied by gravimetric determinations, by X-ray diffraction analysis of the residual cellulose and by monitoring of the molar mass decrease over different time intervals, using size-exclusion chromatography. The disordered regions, even of cellulose with the highest molar mass degraded in the initial minute of liquefaction. However, the highly ordered cellulose regions remained relatively stable for a longer time. None the less, partial degradation of the highly ordered regions of the cellulose was achieved.     

N-叔丁基-α-苯基硝酮对纤维素超临界乙醇液化产物分布的影响

以N-叔丁基-α-苯基硝酮(PBN)为自由基结合剂,采用间歇式高温高压反应釜对玉米秸秆纤维素进行超临界乙醇液化,考察PBN用量(浓度)和反应温度(活性)对纤维素液化产物及生物油中主要化合物分布的影响。结果表明,在320℃,仅有超临界乙醇作用,生物油收率为37.17%,挥发分收率高达50.08%;随着PBN用量增加到0.4 g,生物油收率最高提升至48.35%,挥发分最低下降到35.65%。在超临界乙醇和PBN作用下,随着反应温度从250℃升高至340℃,纤维素转化率从23.10%急剧增加至88.92%,生物油收率从19.18%上升到最高48.35%(320℃)后略有下降,挥发分也从6.03%急剧上升至50.28%。GC-M S结果显示,酯类、酮类、烃类、醇类、酸类及苯类化合物是生物油的主要成分,各组分的最高相对含量分别为27.91%、15.77%、13.44%、12.42%、16.07%、19.81%。实验结果证实了PBN对纤维素超临界乙醇液化产物及生物油组分分布产生了较明显的影响,尤其能通过与含苯基、乙基等活性碎片结合促进挥发分与生物油之间的转化,且PBN用量及液化温度的改变可以促使生物油中主要化合物发生不同程度的相互转化。     

分子动力学模拟压水反应堆中联氨对水的影响

本文采用分子动力学方法模拟在常温常压下(1 atm,298 K)和在压水堆环境下(155 atm,626 K),水分子数为256,联氨(N₂H₄)分子数为0,25,50,75等不同数目时,水和联氨粒子系统的动力性质和微观结构.同时探讨了联氨分子的引入对水中溶解氧的影响.从模拟结果可知,在常温常压下,当联氨的分子数为0,25,50,75时,粒子系统的均方位移会随联氨分子数的增加而增加;联氨分子数为0与为25,50,75比较时会少一个数量级;压水堆环境下,联氨分子数 关键词： 分子动力学 压水堆 联氨     

有压腔式吸热器复杂耦合换热机理数值研究

本文建立了有压腔式太阳能吸热器(PVSR)轴对称计算模型,运用蒙特卡罗光线追踪法(MCRT)模拟了二次聚光器(SC)与有压腔式吸热器(PVR)系统内聚光过程与光热转换过程,进而与计算流体与传热的有限容积方法(FVM)结合研究了高温高压吸热器内复杂耦合传热过程.在此基础上,进一步对比考察了考虑不同换热过程的换热机理,分析...     

Reaction kinetics of stover liquefaction in recycled stover polyol

The purpose of this research was to study the kinetics of liquefaction of crop residues. The liquefaction of corn stover in the presence of ethylene glycol and ethylene carbonate using sulfuric acid as a catalyst was studied. It was found that the liquefaction yield was a function of ratio of solvent to corn stover, temperature, residence time, and amount of catalyst. Liquefaction of corn stover was conducted over a range of conditions encompassing residence times of 0–2.5 h, temperatures of 150–170°C, sulfuric acid concentrations of 2–4% (w/w), and liquefaction reagent/corn stover ratio of 1–3. The liquefaction rate constants for individual sets of conditions were examined using a first-order reaction model. Rate constant increased with the increasing of liquefaction temperature, catalyst content, and liquefaction reagent/corn stover ratio. Reuse of liquefied biomass as liquefying agent was also evaluated. When using recycled liquefied biomass instead of fresh liquefaction reagent, the conversion is reduced. It appeared that 82% of liquefaction yield was achieved after two times of reuse.     

模糊识别模式在粉土液化判别中的应用

基于模糊数学的基本原理和方法,分析了粉土液化的影响因素,选取粉土的平均粒径,相对密度,标准贯入击数和上覆有效压力作为评价指标,构造粉土液化的模糊识别模式。验证和应用结果表明,模糊识别模式具有很好的映射能力,是粉土液化势预测的有效手段。     

水电站坝的砂层地基地震液化可靠度研究

对四川地区江河上数座水电站坝基砂层的26组动力三轴试验资料进行了统计分析,基于动剪应力比法的液化判别方法推导了的地震液化的极限状态方程,使用蒙特卡洛随机抽样的方法计算了砂层液化的失效概率,并对某水电站的厂房地基砂层的液化可靠度进行了计算分析。研究表明,统计按粉砂样总体和中细砂样总体划分较为合理;砂层的动剪应力比可采用正态分布;电站砂层地基地震液化的最危险工况为,闸坝盖重加稳定的向上渗流及遭遇Ⅶ度地震荷载,为高液化风险,其液化概率随埋深加大而增大,最危险部位为砂层底板,对坝基砂层应进行抗液化处理。     

Selective pressurized liquid extraction of estrogenic compounds in soil and analysis by gas chromatography-mass spectrometry

A selective pressurized liquid extraction (SPLE) method, followed by gas chromatography–mass spectrometry (GC–MS), for the simultaneous extraction and clean-up of estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), estriol (E3) and bisphenol A (BPA) from soil samples is described. The on-line clean-up of soil by SPLE was achieved using different organic matter retainers, including silica, alumina and Florisil, the most effective being silica. Thus, different amounts of silica, in conjunction with different extraction solvents (acetone, ethyl acetate, isohexane and dichloromethane), either alone or in combination, were used to extract the target chemicals from spiked soil samples. It was shown that 3 g silica resulted in satisfactory rates of recovery of target compounds and acetone:dichloromethane (1:3, v/v) was efficient in extracting and eluting estrogenic compounds for SPLE. Variables affecting the SPLE efficiency, including temperature and pressure were studied; the optimum parameters were 60 °C and 1500 psi, respectively. The limits of detection (LODs) of the proposed method were 0.02–0.37 ng g⁻¹ for the different estrogenic chemicals studied. The outputs using the proposed method were linear over the range from 0.1 to 120 ng g⁻¹ for E1, E2, EE2, 0.2–120 ng g⁻¹ for E3, and 0.5–120 ng g⁻¹ for BPA. The optimized method was further verified by performing spiking experiments in natural soil matrices; good rates of recovery and reproducibility were achieved for all selected compounds and the method was successfully applied to soil samples from Northeast Scotland, for the determination of the target compounds.