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C. N. Cacaval E. C. BuruianÎ D. Rou E. Rusu G. E. Grigoriu V. Brboiu 《Polymer International》1985,17(4):343-346
Thermogravimetry and pyrolysis in combination with gas chromatography and infrared spectroscopy were the experimental techniques applied to the thermal degradation of cinnamoylated poly(vinyl alcohol) samples, constituted from vinyl alcohol-vinyl cinnamate photocrosslinkable copolymers. The thermal decomposition products include gases, liquids and solids. The gases are formed from saturated and unsaturated volatile hydrocarbons C1? C4, carbon monoxide and carbon dioxide. The liquid fraction includes aromatic hydrocarbons and some oxygenated organic compounds. The solid product identified in the greatest amount was cinnamic acid. The content in the thermal decomposition products varies considerably both with copolymer composition and temperature. 相似文献
54.
讨论了以硫化氢和十二碳烯为原料 ,以固体酸为催化剂 ,采用滴流床反应器连续法合成叔十二碳硫醇工艺中叔十二碳硫醇合成液 (粗硫醇 )的快速分析方法。对采用毛细管柱气相色谱和填充柱气相色谱分析粗硫醇的方法进行了比较。结果表明 ,采用填充柱气相色谱法分析粗硫醇 ,方法简便、快速、可靠 ;完成一次分析只需 1min ,相对标准偏差小于 1%。 相似文献
55.
Ke-Shun Liu 《Journal of the American Oil Chemists' Society》1994,71(11):1179-1187
Theoretically, preparation of fatty acid methyl esters (FAMEs) deals with reversible chemical reactions in a complex system.
Methodologically, there are numerous ways, generally characterized by the type of catalysts used and steps involved. Although
there are more than a half dozen common catalysts, the majority fall into either acidic (HCl, H2SO4 and BF3) or alkaline types (NaOCH3, KOH and NaOH), with each having its own catalytic capability and application limitations. In terms of steps, many conventional
methods, including those officially recognized, consist of drying, digestion, extraction, purification, alkaline hydrolysis,
transmethylation/methylation and postreaction work-up. Although these methods are capable of providing reliable estimates
if some precautions are taken, they are cumbersome, time-consuming and cost-inefficient. A new approach has been to transmethylate
lipidsin situ. Due to its simplicity, high sensitivity, comparable reliability and capability to determine total fatty acids, the method
of direct transmethylation is finding a unique place in lipid determination. Regardless of which method is used, quantitative
methylation requires chemists to take precautions at every step involved, particularly during FAME formation and subsequent
recovery steps. Evidently, there is an urgent need for more systematic studies, guided by the chemical principle of reactions
involved and physicochemical properties of regents and end products, into factors affecting these steps. Hopefully, this will
lead to an improved method, which measures lipid composition in biological materials not only with high accuracy but also
with high efficiency and minimum costs. 相似文献
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介绍了用气相色谱分析叔丁醇两步氧化制甲基丙烯酸液相产物的组成,该分析方法能够分析液相产物中的醛类,酮类和酸类化合物共计9个组分,C2-C4有机酸无记忆效应,其色谱峰不拖尾,该分析方法的相对标准偏差≤8.5%,回收率在94.5%-103.7%之间,是一种快速,准确,操作简单的分析方法。 相似文献
58.
A rapid and easy analysis method for polymers is presented. The method involves sample preparation by SFE, separation of the extracted compounds by SFC and simultaneous quantitative detection by FID, as well as identification of unknowns by MS. The applications illustrate how structural research work and routine polymer analysis can be done with this time saving method. 相似文献
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Sylvia V A Uzochukwu Esther Balogh Owen G Tucknot Mervyn J Lewis Patrick O Ngoddy 《Journal of the science of food and agriculture》1994,64(4):405-411
Palm wine and pasteurised palm sap volatiles were collected, concentrated on a Tenax GC and analysed by gas chromatography and gas chromatography-mass spectrometry. Eighty-two components were identified: 47 esters, 9 alcohols, 5 acids, 6 carbonyls, 2 acetals, 4 terpenes and 9 hydrocarbons. These had all been found previously in conventional wines. Odour evaluation of the separated palm wine components as they eluted suggested that no one compound is responsible for the characteristic palm wine odour. The acetates of higher alcohols and the ethyl esters of straight-chain aliphatic C6-C10 acids seemed to be important and may play a big role in imparting the fruity nuances of characteristic palm wine odour. Their association with alcohols seemed also to be necessary for the expression of typical palm wine odour. The qualitative difference between palm sap aroma and palm wine aroma appeared to be due mainly to the presence of these esters and alcohols in palm wine and their apparent absence from palm sap, as well as to the presence of some low-boiling esters and alcohols in palm sap and their apparent absence from palm wine. 相似文献