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排序方式: 共有181条查询结果,搜索用时 31 毫秒
1.
Transesterification of waste fryer grease (WFG) containing 5–6 wt.% free fatty acid (FFA) was carried out with methanol, ethanol, and mixtures of methanol/ethanol maintaining the oil to alcohol molar ratio of 1:6, and initially with KOH as a catalyst. Mixtures of methanol and ethanol were used for transesterification in order to use the better solvent property of ethanol and rapid equilibrium using methanol. Formation of soap by reaction of FFA present in WFG with KOH instigated difficulty in the separation of glycerol from biodiesel ester. To untangle this problem, two-stage (acid and alkali catalyzed) method was used for biodiesel synthesis. More than 90% ester was obtained when two-stage method was used compared to ∼ 50% ester in single stage alkaline catalyst. In the case of mixed alcohol, a relatively smaller amount of ethyl esters was formed along with methyl esters. Acid value, viscosity, and cetane number of all the esters prepared from WFG were within the range of the ASTM standard. Esters obtained from WFG showed good performance as a lubricity additive.  相似文献   
2.
Different amounts (50-170 php--parts per hundred parts of EVA, 33-63 wt%) of two tackifiers (hydrogenated rosin ester, polyterpene resin) were added to an ethylene vinyl acetate (EVA) copolymer containing 28 wt% vinyl acetate. The EVA and the tackifier were characterized using infrared (IR) spectroscopy, DSC measurements, and stress-controlled plate-plate rheology. The properties and compatibility of the EVA-tackifier mixtures were studied using DSC, DMTA, and stress-controlled plate-plate rheology. Immediate adhesion was measured as a quantification of tack, and the T-peel strength of roughened styrene-butadiene rubber/EVA-tackifier adhesive joints was also obtained. The increase in the amount of tackifier noticeably changed the crystallinity of polyethylene blocks in the EVA, and the temperature at the cross-over between the curves of the storage and loss moduli as a function of the temperature was displaced to a lower value. Whereas the hydrogenated rosin ester was compatible with the amorphous ethylene vinyl acetate copolymer regions of the EVA (Tg value increased) reducing its crystallinity, the polyterpene resin was compatible with the polyethylene blocks of the EVA (T g value was not modified), increasing its crystallinity. Immediate adhesion of the EVA-tackifier mixtures was improved by adding both hydrogenated rosin ester and polyterpene tackifiers. On the other hand, there was an optimum tackifier content at which the maximum T-peel strength value was obtained.  相似文献   
3.
混合指示剂单相滴定法测定烷基磷酸酯钾盐   总被引:1,自引:0,他引:1  
本研究用混合指示剂单相滴定法测定ISO标准方法所不能测定的磷酸盐阴离子表面活性剂的浓度.测定PK、E502A、昆山PK的常数K分别为355.lg/M、420.7g/M和344.0g/M,变异系数分别为1.45%、0.59%和1.26%,测定实际试样的加标回收率为98.2~103.9%.方法准确、简单、快速,不需用毒性较大的有机溶剂,本法适用于化纤油剂和涤纶短纤维上油率等的测定.  相似文献   
4.
A Life Cycle Assessment (LCA) study of HidroBioDiésel (HBD) was carried out. This partly renewable diesel fuel is obtained from the co-processing of soybean vegetable oil with conventional fossil fuel in hydrotreating facilities of crude oil refineries. The environmental profile of HBD was assessed for the fossil energy use and climate change impact categories. The production systems of equivalent fuels -blends of Fatty Acid Methyl Ester (FAME, a biofuel obtained by means of transesterification of vegetable oil) and mineral diesel with sulphur content below 10 ppm were also assessed for comparison purposes. The environmental performance of HBD systems compares favourably to those of FAME and diesel blends for the selected impact categories. The estimated environmental benefits of HBD (assuming a 13% renewable blend) include reductions of up to 2% in fossil energy use and 9% in climate change impacts.  相似文献   
5.
The influence of polyesters end-groups on cyclic oligoester formation is investigated using a series of hydroxy-, carboxy- and methylester-terminated aliphatic polyesters, in the presence of various ester interchange catalysts. The presence of hydroxy end-groups is the preponderant factor on cyclodepolymerization kinetics. This indicates that the main reaction is the intramolecular hydroxy–ester interchange reaction between hydroxy end-groups and ester functions in the chain. Carboxy-ester and ester–ester interchanges play a minor role, as the cycle-chain equilibrium is reached only very slowly when carboxy- or ester-terminated polyesters are reacted. High temperature and the presence of tin catalysts are also favorable factors, while, as expected, dilution shifts the equilibrium toward the formation of high yields of cyclic oligoesters. A mechanism is proposed, based on the reverse of the “coordination-insertion” mechanism established for the ring-opening polymerization of lactones.  相似文献   
6.
关于酱油香型的探讨   总被引:2,自引:0,他引:2  
该文通过对低盐固态发酵法和高盐稀态发酵法生产酱油所用原料和工艺条件的差别,分别论述了所产酱油香气成分的特点。即高盐稀态酱油中醇类、酚类、酯类含量高,而低盐固态酱油中HEMF和各种吡嗪物质含量较多,并分析论述了酱油香型中酱香和酯香的区别。  相似文献   
7.
通过同步法制备了一系列聚氨酯/乙烯基酯树脂互穿聚合物(PU/VER-IPN),研究了PU/VERIPN性能的影响因素。结果表明:随着PU含量的增加,IPN的热稳定性能有一定程度的提高;而VER的含量增加,PU/VER-IPN的剪切强度提高。实验还发现:当PU/VER-IPN为部分相容的多相微区结构时,对增加IPN的力学损耗更有利  相似文献   
8.
酯固化碱性酚醛树脂粘结剂及其固化机理的研究   总被引:3,自引:0,他引:3  
研究了酯固化碱性酚醛树脂的合成工艺,得到了高强度的粘结剂;分析了硅烷偶联剂对粘结强度的影响,并对酯的固化机理作了初步探讨。  相似文献   
9.
环境友好润滑剂的特点及发展   总被引:26,自引:3,他引:26  
阐述了绿色友好润滑剂的生物降解性和摩擦化学特点,提出了环境友好润滑剂在发展过程中存在的主要问题,并对未来的发展趋势进行了预测。  相似文献   
10.
The purpose of this research is an experimental study of Calophyllum inophyllum (CI)-based trymethylolpropane (TMP) ester as an energy-saving and biodegradable lubricant and compare it with commercial lubricant and paraffin mineral oil using a four-ball tribometer. CI-based TMP ester is a renewable lubricant that is nonedible, biodegradable, and nontoxic and has net zero greenhouse gases. The TMP ester was produced from CI oil, which has high lubricity properties such as higher density, higher viscosity at both 40°C and 100°C and higher viscosity index (VI). Experiments were conducted during 3,600 s with constant load of 40 kg and constant sliding speed of 1,200 rpm at temperatures of 50, 60, 70, 80, 90, and 100°C for all three types of lubricant. The results show that CI TMP ester had the lowest coefficient of friction (COF) as well as lower consumption of energy at all test temperatures, but the worn surface roughness average (Ra) and wear scar diameter were higher compared to paraffin mineral oil and commercial lubricant. Before 80°C, CI TMP ester actually has a higher flash temperature parameter (FTP) than paraffin mineral oil and as the temperature increases, the FTP of TMP ester decreases. The worn surfaces of the stationary balls were analyzed by scanning electron microscopy (SEM) and results show that CI TMP ester has the highest wear compared to paraffin mineral oil and lowest wear compared to commercial lubricant. However, CI TMP ester is environmentally desired, competitive to commercial lubricant, and its use should be encouraged.  相似文献   
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