共查询到20条相似文献,搜索用时 781 毫秒
1.
固定床渣油加氢脱金属废催化剂上焦炭结构和组成沿床层变化研究 《燃料化学学报》2019,47(2):167-173
针对取自中石油某装置不同床层轴向位置的工业固定床渣油加氢脱金属废催化剂,采用元素分析、热重分析、X射线光电子能谱、傅里叶变换红外光谱和核磁共振碳谱等,研究了催化剂上沉积焦炭的结构组成特征参数。结果表明,不同轴向位置废催化剂上的焦炭具有某些共同特征,如相同的碳类型和官能团等,但其结构和组成各不相同。模拟建立了基于各种表征结果的焦炭结构组成模型,并利用可计算核磁共振波谱化学位移和预测核磁共振谱图的gNMR软件对所建立焦炭模型的精确性进行了验证,表明模型与实验结果具有很好的一致性。 相似文献
2.
针对取自中石油某装置不同床层轴向位置的工业固定床渣油加氢脱金属废催化剂,采用元素分析、热重分析、X射线光电子能谱、傅里叶变换红外光谱和核磁共振碳谱等,研究了催化剂上沉积焦炭的结构组成特征参数。结果表明,不同轴向位置废催化剂上的焦炭具有某些共同特征,如相同的碳类型和官能团等,但其结构和组成各不相同。模拟建立了基于各种表征结果的焦炭结构组成模型,并利用可计算核磁共振波谱化学位移和预测核磁共振谱图的gNMR软件对所建立焦炭模型的精确性进行了验证,表明模型与实验结果具有很好的一致性。 相似文献
3.
4.
5.
烷基甲基二烯丙基溴化铵共聚物是一种新型疏水改性的聚皂,应用多种核磁共振分析技术对其结构和共单体的组成进行了定量的讨论.研究结果表明,在测定化学结构和性质上比较接近的共单体组成时,核磁共振方法是一种有效的工具. 相似文献
6.
7.
8.
9.
10.
固体核磁共振技术是一种定量分析固体材料结构与组成的强有力手段,结合固体核磁共振和常规x-射线衍射(XRD)、 x-射线吸收谱(XAS)等表征方法可对锂/钠离子电池材料在电化学反应中的结构演化过程进行全面的分析. 例如通过固体核磁共振研究, 可获得不同合成与修饰条件下, 锂/钠离子电池电极和电解质材料体相以及电极/电解质界面层的化学组成、局域结构和离子扩散动力学等信息,为高性能电池材料的设计和研发提供重要的基础数据. 本文结合本课题组的研究工作,综述了近三年来国内外固体核磁共振技术在锂/钠离子电池电极、电解质材料以及固体电解质界面膜(SEI)研究中的应用和进展. 相似文献
11.
12.
A method of gas chromatography is described for the rapid qualitative and quantitative analysis of tar heavy oils: naphthalenic oils, wash oils, anthracenic oils, etc.The apparatus used can be easily constructed in an industrial laboratory. The results are calculated by a very simple method of internal normalization requiring no previous standardization.The composition of various oils, determined by the proposed method, is given. 相似文献
13.
14.
Francesca Capetti Arianna Marengo Cecilia Cagliero Erica Liberto Carlo Bicchi Patrizia Rubiolo Barbara Sgorbini 《Molecules (Basel, Switzerland)》2021,26(18)
The quality control of essential oils (EO) principally aims at revealing the presence of adulterations and at quantifying compounds that are limited by law by evaluating EO chemical compositions, usually in terms of the normalised relative abundance of selected markers, for comparison to reference values reported in pharmacopoeias and/or international norms. Common adulterations of EO consist of the addition of cheaper EO or synthetic materials. This adulteration can be detected by calculating the percent normalised areas of selected markers or the enantiomeric composition of chiral components. The dilution of the EO with vegetable oils is another type of adulteration. This adulteration is quite devious, as it modifies neither the qualitative composition of the resulting EO nor the marker’s normalised percentage abundance, which is no longer diagnostic, and an absolute quantitative analysis is required. This study aims at verifying the application of the two above approaches (i.e., normalised relative abundance and absolute quantitation) to detect EO adulterations, with examples involving selected commercial EO (lavender, bergamot and tea tree) adulterated with synthetic components, EO of different origin and lower economical values and heavy vegetable oils. The results show that absolute quantitation is necessary to highlight adulteration with heavy vegetable oils, providing that a reference quantitative profile is available. 相似文献
15.
G. Pérez-Caballero J. M. Andrade S. Muniategui D. Prada 《Analytical and bioanalytical chemistry》2009,395(7):2335-2347
The capability of single-reflection near-IR (NIR) spectroscopy to differentiate, characterize and monitor the fate of a set
of hydrocarbons spilled in the marine environment was compared with that of multiple-reflection horizontal attenuated total
reflection mid-IR (ATR-MIR) spectroscopy. Multivariate pattern recognition techniques [principal component analysis (PCA),
multivariate polynomial regression, cluster analysis and potential curves] were applied to unravel the major trends of the
weathering processes of four generic types of crude oils and two heavy fuel oils spilled under controlled conditions for almost
4 months. A chemical interpretation of the NIR spectra related the weathering processes and the PCA loadings, which had not
already been done in the literature. Weathering for both light and heavy products was characterized by a contrast among the
linear aliphatic structures (more volatile and easy to degrade) and the branched and aromatic structures (more recalcitrant).
Potential curves were applied to model each product and determine objectively whether unknown samples could be classified
correctly. Polynomial regression on the PCA scores was employed to evaluate the time elapsed from the oil spillage to its
sampling; this represents a new approach to assess the age of a hydrocarbon lump. In general, NIR spectroscopy yielded good
results when light crude oils were studied, whereas ATR-MIR spectroscopy led to satisfactory results for both light and heavy
products. 相似文献
16.
A method is proposed for the sample preparation of heavy oil residues characterized by viscosity of more than 700 mm2/sec at 100°C to study their elemental composition. It is shown that a wide range of elements can be determined in heavy oil residues by inductively coupled plasma atomic emission spectrometry (IC-AES) when the sample dissolved in an organic solvent is injected into the instrument. The optimal parameters for the determination of metals in heavy oil residues by ICP-AES are selected, including an organic solvent and the method of sample dilution. The results of elemental analysis of heavy residues of oils from Chernigovskoe, Shpakovskoe, and Samarskoe deposits are compared. The developed method for determining metals in heavy oil residues significantly reduces the analysis time and does not require complex sample preparation. 相似文献
17.
The chemical composition of 27 oil samples of Myrtus communis isolated from leaves collected in three locations in north-eastern Algeria was investigated by GC(RI) and 13C NMR spectroscopy. Yields ranged between 0.2-1.2% (w/w). The chemical composition of the oils was largely dominated by monoterpene hydrocarbons, with alpha-pinene (40.5-64.0%), 1,8-cineole (10.9-29.1%) and limonene (6.7-8.2%) being the major compounds. In all the samples, 3,3,5,5,8,8-hexamethyl-7-oxabicyclo[4.3.0]non-1(6)-ene-2,4-dione was identified (0.8-1.5%). The composition is similar to that reported for myrtle oils from Corsica, Sardinia and Tunisia, but differed from that of Moroccan and Spanish myrtle oils. 相似文献
18.
Silva SL Silva AM Ribeiro JC Martins FG Da Silva FA Silva CM 《Analytica chimica acta》2011,707(1-2):18-37
The state of the art in the characterization of heavy crude oil mixtures is presented. This characterization can be done by different techniques, such as gas chromatography (GC), high performance liquid chromatography (HPLC), thin layer chromatography (TLC), infrared spectroscopy (IR), Raman spectroscopy, nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). Nuclear magnetic resonance spectroscopy is the technique of choice due to its capability to provide information on the chemical nature of individual types of hydrogen and carbon atoms in different and complex mixtures of crude oils. The progress made in the interpretation of the NMR spectra with the development of new NMR techniques and different multivariate data analyses could give relevant information about the identification and characterization of hydrocarbons and their physical and chemical properties. These progresses can improve the refining industries operation as a result of the better knowledge on the crude composition that is fed in the refining process, as well as in the prediction of better operating conditions to obtain refined products with desired specifications and in quantities desirable to meet the market demands. The improvement in the refining operation conditions is reflected in economical benefits. 相似文献
19.
Michelle Gonçalves Mothé Cheila Gonçalves Mothé Carlos Henrique Monteiro de Carvalho Marcia Cristina Khalil de Oliveira 《Journal of Thermal Analysis and Calorimetry》2013,113(2):525-531
Present study investigates thermal behavior of two heavy crude oils with different °API values by simultaneous thermogravimetry–differential scanning calorimetry–fourier transform infrared spectroscopy (TG–DSC–FTIR), and an evaluation of the chemical element levels present in the oils’ ashes was done by energy dispersive X-ray fluorescence spectrometry. TG and DSC curves were obtained for two samples in nitrogen atmosphere. Among all inorganic components evaluated, the highest concentration in the two oils was SO3. Thus this study may contribute to a better understanding of the thermal behavior of heavy crude oils and their composition. 相似文献
20.
Andersson Barison Caroline Werner Pereira da Silva Francinete Ramos Campos Fabio Simonelli Cesar Antonio Lenz Antonio Gilberto Ferreira 《Magnetic resonance in chemistry : MRC》2010,48(8):642-650
A simple methodology for the determination of the fatty acid composition of edible oils through 1H NMR is proposed. The method is based on the fact that all fatty acid chains are esterified to a common moiety, glycerol, and the quantification is done directly in the 1H NMR spectra through the relationship between the areas of a characteristic signal of each fatty acid and a signal of the glycerol moiety, without the use of mathematical equations. The methodology was successfully applied to determine the fatty acid composition of several edible oils, with equivalent results to those given by the AOAC Official method by gas chromatography. Its main advantages are simplicity and the lack of need for sample pre‐treatment such as derivatization or extraction. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献