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71.
The numerous applications of dextrins resulting from the heating of potato starch with α-amino acids prompted me to check the thermal reactions of starch with hydroxy acids and their lactones, such as citric acid, lactic acid, tartaric acid, and coumarine. The course of reactions was observed by means of Simultaneous TG/DSC Thermal Analyser. The thermal reactions were carried out on convectional and microwave heating. The course of reactions under such conditions was compared and properties of resulting dextrins were recognized. The structure and properties of products were obtained from FTIR spectra, water solubility tests, and pH measurements. It was found, that hydroxy acids and/or products of their thermal transformations reacted with starch and/or resulting dextrins producing esters or crosslinking esterification of dextrins took place. The properties of new dextrins were presented in order to check, in further studies, their application for selective flotation of complex metal ores and their suitability as prebiotics. 相似文献
72.
Biodiesel has emerged as one of the most promising renewable energy to substitute existing petroleum-derived diesel fuel being used in transportation sectors. Among the various feedstocks reported for biodiesel production, Moringa oleifera oil is becoming a promising replacement for conventional diesel fuel. Therefore, this work provides a comprehensive overview of the recent progress in biodiesel production from Moringa oleifera oil. The physicochemical properties, fatty acid composition of oil and methyl esters, oil extraction methods, esterification, and transesterification process, and purification methods employed in the biodiesel production have been discussed. 相似文献
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74.
A new approach for isolation and identification of elecrtophilic mutagens from complex matrix was developed.Thiosulfonic anion was immobilized onto polystyrene beads and used as separation media.Potassium polystyryl-thiosulfonate,prepared from polystyryl- sulfonyl chloride and KHS,was observed to selectively react with model electrophilic mutagens such as alkyl halides,α-chloroketones andα-chloroesters to produce polystyryl-thiosulfonic esters.After separation from other nonreactive organic compounds,the beads then reacted with ethanethiol to produce unsymmetrical ethyl disulfides which are easily detected by GC/MS.For one mutagenic compound,only one unsymmetrical disulfide was found to contain its structure part.Thus,the structure of the parent mutagens could be deduced from that of the unsymmetrical disulfides.The degree of functionaiization of the potassium polystyryl-thiosulfonate resin was 1.11 mmol/g.Its reactivity was discussed and its recycling method was reported here. 相似文献
75.
文章在比较研究了几种草酸铁络合物体系对两种酞酸酯DBP和DEHP的光催化降解情况.结果表明:草酸铁络合物和草酸铁络合物/H2O2体系在遮光条件下对DBP和DEHP没有降解作用.在中性pH值条件下,DBP和DEHP在几种反应体系中的降解速率依次为:UV/草酸铁络合物/H2O2>UV/H2O2>UV/草酸铁络合物>UV>太阳光/草酸铁络合物.UV与草酸铁络合物对DBP和DEHP光降解的协同作用不强,增强因子f分别为1.20和1.07.UV、草酸铁络合物与H2O2的对DBP光降解协同作用也不明显,增强因子f=1.18. UV与H2O2对DBP光降解存在明显的协同作用,增强因子f=8.78. 相似文献
76.
77.
土壤中酞酸酯的分析方法研究 总被引:8,自引:2,他引:8
经过系统研究,建立了以正已烷/丙酮(V/V:2/1)为溶剂,对土壤进行超声萃取,然后以浓H_2SO_4进行纯化的分析土壤中酞酸酯的方法。本方法具有省时、省溶剂、空白低及纯化效果好的特点,具有很强的实用性。 相似文献
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79.
Two closely related forms ofOphrys insectifera were observed in the field to attract different pollinator species selectively.O. i. ssp.insectifera attracted males of two species ofArgogorytes (Sphecidae, Hymenoptera Aculeata) andO. i. ssp.aymoninii attractedAndrena combinata males (Andrenidae, Apoidea, Hymenoptera Aculeata). A third form,O. aff.i. ssp.insectifera, attracted none of these three species. Volatile compounds from flowers and inflorescences of the three forms (originating from Öland, Sweden, and Aveyron, France) were collected, using entrainment, enfleurage, and solvent extraction techniques, and identified by gas chromatography — mass spectrometry. Scent differences between the three forms were confirmed in the amounts of aliphatic hydrocarbons (C11–C19), methyl esters (C14–C18), short chain aliphatic 1-alcohols (C6–C12), and monoterpene alcohols (C10). 相似文献
80.