排序方式: 共有31条查询结果,搜索用时 15 毫秒
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Orlando David Henrique dos Santos Maria Fernanda Pires de Camargo Fernanda Frota de Andrade Pedro Alves da Rocha Filho 《Journal of Dispersion Science and Technology》2013,34(7):997-1001
During evaporation, the rate between volatile and nonvolatile components in an emulsion changes. In this study, emulsions of marigold and canola oil were made according to a phase diagram, simulating the decreasing water amount that happens when the water evaporates from an emulsion. In addition, two basic emulsions were submitted to evaporation and then to microscopic analysis to compare the results of both tests. It was observed that when the water rate decreases, the liquid‐crystalline phase changes its organization, reaching a proportion that it is not hydrated anymore, having a solid aspect. Moreover, these emulsions submitted to evaporation remained to show lamellar phase even when there was no water in the formulation. This is interesting to understand the behavior of an emulsion after it is applied under the skin. 相似文献
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Determination of capsaicinoids in peppers by microwave-assisted extraction-high-performance liquid chromatography with fluorescence detection 总被引:2,自引:0,他引:2
In this study, a simple method for the determination of free fatty acids, phytosterols, tocopherols, mono and diglycerides present in canola oil deodorizer distillate (DD) and soapstock samples was developed. Analytes were derivatized “in situ” using a mixture of hexamethyldisilazane (HMDS), pyridine and trifluoroacetic acid; separated by gas chromatography (GC) with mass spectrometry (MS) for final detection. Two drying procedures were evaluated for drying deodorizer distillate samples before derivatization: freeze drying and drying at 100 °C for 24 h. The use of high temperatures caused the degradation of tocopherols and phytosterols, while lyophilization did not affect the substances negatively. The chromatographic conditions used in this work allow for the separation and quantification of oleic, linoleic and linolenic acids, monoolein and monolinolein in both samples, and brassicasterol and α-tocopherol in deodorizer distillate samples. MS provided an accurate identification for the compounds which were at very low concentrations (>0.09%). Oleic acid was the most abundant compound in both samples. Deodorizer distillate was an important source of tocopherols which were not detected in the soapstock samples. 相似文献
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桦甸页岩油柴油馏分加氢精制生产清洁燃料油的研究 总被引:3,自引:0,他引:3
柴油馏分(200℃~360℃)在桦甸页岩油中约占41%。其中,硫、氮及不饱和烃含量较高,含硫化合物以苯并噻吩类及二苯并噻吩类化合物为主,而氮化物中的碱性氮化物和非碱性氮化物的含量相当。实验中分别以硫化态的CoMo/Al2O3及NiW/Al2O3为催化剂,利用固定床小型加氢反应装置,考察了不同工艺条件对桦甸页岩油柴油馏分加氢脱硫及加氢脱氮效果的影响。结果表明,反应温度升高,增大反应压力,降低体积空速,对脱硫、脱氮都是有利的,特别是对加氢脱氮影响最为明显,而氢油体积比的影响相对较小。两种催化剂活性比较发现,对于该页岩馏分油而言,两种催化剂的加氢脱硫效果相差不大,而NiW/Al2O3的加氢脱氮效果却明显好于CoMo/Al2O3。在选择的工艺条件下,对桦甸页岩油柴油馏分进行加氢精制得到的产品油中杂原子和不饱和烃含量低,密度小,芳香烃含量少,可作为优质清洁柴油直接使用。 相似文献
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Summary The application of capillary supercritical fluid chromatography (SFC) to the analysis of a middle distillate fuel is described. Small diameter (50m i.d.) fused-silica capillary columns coated with crosslinked 50% phenyl polymethylphenyl siloxane provided high separation efficiency and good compatibility with flame ionization detection. High resolution separations of the chemical class fractions obtained by adsorption chromatography on alumina were obtained using carbon dioxide as the supercritical mobile phase and simple pressure programming techniques. In addition to the less polar fuel components, supercritical carbon dioxide allowed chromatography of the nitrogen-containing polycyclic aromatic hydrocarbon fraction and the hydroxylated polycyclic aromatic materials. 相似文献
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This paper describes the use of multidimensional capillary gas chromatography for analysis of individual components in a C9? C10 aromatic hydrocarbon pyrolysis distillate containing substantial amounts of aromatic olefins. By coupling this GC-GC system on-line to a mass spectrometer difficulties in identifying overlapping compounds were overcome. No coelution of different types of compound was observed, but a few isomeric compounds such as methylstyrenes were poorly separated. 相似文献
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渣油窄馏分的加氢转化特性 总被引:2,自引:3,他引:2
利用超临界流体萃取分馏装置,获得了大港常压渣油,沙特阿拉伯轻质原油和中质原油的减压渣油的窄馏分,并分析了SFEF窄馏分的性质。在100ml的高压反应釜内,利用破碎的工业Ni-Mo/Al2O3加氢裂化催化剂,在氢初压8.5MPa,反应温度400℃,反应时间240min的条件下,研究了渣油窄馏分的催化加氢转化特性及春变化规律。结果表明,随SFEF馏分变量,其脱硫和脱氮效果明显变差,裂化反应生成汽油,柴 相似文献
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酱香型酒香气成分研究:1.珍酒,茅台酒空杯香分离及官能色谱探索 总被引:4,自引:0,他引:4
本文系统地研究了酱香型酒主体香的分离方法,摸索出“溶剂萃取-自然挥发-溶解”的酱香型酒空杯香的分离方法,首次从珍酒、茅台酒中分离出典型的空杯香。用在线色谱闻香系统研究了酱香型酒空杯香的化学成分,同时进行色谱测定及嗅闻。结果表明,空杯香是多种成分构成的复合香。 相似文献
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酱香型酒香气成分研究:2.珍酒,茅台酒空杯香成分的GC/MS分析 总被引:1,自引:0,他引:1
用色质联用(GC/MS)法测定酱香型酒空杯香的化学成分,鉴定出13种化合物,并测定了它们的相对含量,其中以十六酸乙酯、油酸乙酯、亚油酸乙酯为主。 相似文献