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生物柴油的催化改性对其冷滤点的影响 总被引:4,自引:1,他引:3
利用HZSM-5型分子筛作为催化剂,在250℃~350℃、0.01MPa~0.04MPa的条件下,对生物柴油的主要组分油酸甲酯、棕榈酸甲酯、硬酯酸甲酯、亚油酸甲酯、月桂酸甲酯进行催化改性,以达到降低生物柴油冷滤点(CFPP)的目的。实验研究了反应温度和反应真空度对各脂肪酸甲酯产物的冷滤点、结炭率、碘值的影响,以该实验数据为依据,将动物油经过酯交换制备的生物柴油(AFE)进行催化改性。结果表明,在300℃~350℃,对饱和脂肪酸甲酯改性有很好的降凝效果,产物碘值升高;油酸甲酯通过改性,也取得了很好的降凝效果,产物碘值下降,在该反应条件下改性饱和脂肪酸甲酯和油酸甲酯催化剂的结炭率保持在5%以下;而亚油酸甲酯仅在350℃时改性才有降凝效果,且结炭率在10%以上。生物柴油(AFE)催化改性达到最佳降凝效果的条件为300℃~325℃,0.01MPa,改性后的的酸值小于0.6mg/g,冷滤点下降了19℃,碘值(I.V)为44.32g/100g,运动黏度(μt)为4.397mm2/s,并且催化剂结炭率保持在5%以下。 相似文献
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设计了以柴油中饱和烃含量及碳数分布测定、聚丙烯酸高级醇酯(PTA)的合成与纯化、PTA的红外表征与分子量测定、PTA降凝性能评价等4个模块组成的综合实验,作为化工专业实验的考核及成绩评定平台。这种考核方式将过程考核与结果考核融合,将笔试、操作、设计融合,可以全面准确地考核学生的有机合成、仪器分析等基础实验技能,同时考核综述、数据处理、实验设计等综合实验能力和实验室工作素质。此外,还能够有效训练学生的学习能力、解决问题能力、实践能力和创新能力,并促进了实验教学水平提高。 相似文献
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聚氯乙烯/聚丙烯酸丁酯/白泥纳米复合材料的研究 总被引:6,自引:0,他引:6
通过多步交换反应及扩散-聚合的方法,使聚丙烯酸丁酯被嵌入到改性层状结构的白泥层间,得到白泥-聚丙烯酸丁酯纳米复合物的微米粒子;然后将聚氯乙烯与白泥-聚丙烯酸丁酯进行熔融共混,制得具有一一特性的有机-无机纳米复合材料,并对复合材料的缺口冲击强度及动态力学性能进行了研究,结果表明,白泥-聚丙烯酸酯含量为5.0wt%时,复合材料的力学性能最佳;聚氯乙烯与高含量的白泥-聚丙烯酸丁酯(分别为25.0wt%和50.0wt%)形成的复合材料,在聚氯乙烯的玻璃化转变温度之前,储能模量出现先降低而后增加的过程。 相似文献
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以富马酸和十六醇为原料、对甲苯磺酸为催化剂、对苯二酚为阻聚剂、甲苯为溶剂,采用直接酯化法制备了富马酸十六醇酯单体(DHF);以富马酸十六醇酯和苯乙烯为聚合单体、过氧化苯甲酰为引发剂,通过自由基聚合制备了富马酸十六醇酯-苯乙烯二元共聚物(FOS)。用IR、1H-NMR对DHF单体及FOS共聚物进行了表征,分析了张家港0# 柴油和胜利海科5# 柴油的正构烷烃分布,考察了共聚物的降滤效果,讨论了降滤作用机理。结果表明,当添加剂量为0.1%时,FOS能使张家港0# 柴油冷滤点降低6℃,胜利海科柴油5# 柴油冷滤点降低3℃;FOS对不同柴油表现出了不同的感受性;与2种商业降凝剂复配后,表现出良好的协同效应,作为商业降凝剂的优良助剂,FOS具有一定的应用前景。 相似文献
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聚氨酯一聚丙烯酸酯共聚乳液的合成研究 总被引:4,自引:0,他引:4
以甲基丙烯酸β-羟乙酯封端的聚氨酯大分子单体与丙烯酸酯类单体进行乳液共聚,合成了以聚丙烯酸酯(PA)为主链、聚氨酯(PU)为侧链的接枝共聚物(PA-g-PU)乳液,用IR光谱和^1H NMR光谱对该聚氨酯大分子单体及PA-g-PU接枝共聚物进行了表征,并对影响聚氨酯-聚丙烯酸酯共聚合的因素进行了探讨。结果表明:聚氨酯大分子单体的加入对乳液聚合的速率造成较大的影响。该体系的表观活化自由能为99.39KJ/mol,Rp∝[I]^0.87,Rp∝[S]^0.12。 相似文献
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两类非线性光学性质稳定的交联极化聚合物 总被引:5,自引:0,他引:5
报道了两类新型含对硝基苯偶氮苯胺发色团的热交联型二阶非线性光学聚合物的合成和极化工艺,双端丙为烯酸酯的分解红(DR)-19热聚合合生成交联型聚丙烯酸酯;双端苯酚封闭异氰酸酯端基的DR-19与含多羟茏牟(丙烯酸-β-羟丙酯-DR-1-MAS)共聚物反应生成交联聚氨酯,DSC测得两者的玻璃化转变温度为125℃和160℃,旋转涂膜后在160℃电晕极化1h可制得良好光学性质的极化膜,采用可见光吸收光谱测定 相似文献
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核/壳结构聚丙烯酸酯塑料增韧剂的制备与结构控制 总被引:8,自引:1,他引:8
核/壳结构聚丙烯酸酯塑料增韧剂的制备与结构控制张会轩戴英杨海东*冯之榴(吉林工学院化工系长春130012)(中国科学院长春应用化学研究所130022)关键词聚丙烯酸酯,增韧剂,制备,种子乳液聚合1996-08-28收稿,1997-01-06修回国家自... 相似文献
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The binary system of water and didecyldimethylammonium bromide (DDeAB), having a double hydrocarbon chain, was found to exhibit exhibit an azeotropic-like phase transition from lamellar liquid crystal to micellar solution. That is, the maximum limiting value of temperatures where the present system is allowed to exist in a lamellar liquid crystal corresponds to the socalled azeotropic point (AZP) or congruent melting point. At this temperature, the compositions of the liquid crystal and micellar solution phases become identical. Upon addition of a small amount of NaBr, the AZP shifts to a high temperature, but the point disappears above 0.375 wt% NaBr in water. The AZP is also increased by adding cholesterol. On the other hand, the transition enthalpies at AZPs are extremely small and almost constant, even if NaBr and cholesterol are added. The sharp DSC peak is observed in the presence of salt, whereas it is broad in the presence of cholesterol. It is considered that salt induces a closely packed state of the liquid crystal phase. Although cholesterol also has an ordering effect on the surfactant aggregates its hydrophobic property increases the phase transition temperature. The phase transition occurs due to a packing change of the hydrocarbon chains of DDeAB molecule from the lamellar to micellar states. The correlation between the movement of AZP and the phase behavior in the presence of salt is also discussed. 相似文献
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Fluorescent method is a powerful tool for genotyping point mutations. Current existing methods usually need cost labeled fluorescent probes, which causes great limitation to their applications in clinic. Here, a fidelity method for genotyping point mutations has been developed based on melting‐point difference without labeled fluorescent probes. The method employs ligase to ligate two specific probes to produce a high melting temperature. The homozygotes and heterozygotes are scored accurately by obvious melting‐point difference among genotypes. This method would provide an accurate and economical‐cost tool for point mutation genotyping. 相似文献
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介绍英国政府化学家研究所(LGC)研制的五种熔点标准物质的熔点和凝固点的定值方法、定值结果及不确定度的估计。 相似文献
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闭杯闪点法测定氢化三丁基锡的闪点 总被引:1,自引:0,他引:1
使用MINIFLASH FLA全自动中温八杯闪点仪(闭杯闪点法)测定了氢化三丁基锡的闪点。探讨了诸多因素如样品的储存状态、点火次数、升温速率、大气压的校正、仪器保养方法等对闪点测定的影响。 相似文献
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Qualitative analysis of the trends in melting temperatures T
m
and boiling temperatures T
b
of organic compounds and related substances supports a concept of van der Waals symmetry suggested earlier by the authors.
Data for substituted methanes, ethanes, ethylenes, benzenes and cyclohexanes, reveal linear T
b
versus M
α patterns but usually non-uniform T
m
versus M
α patterns (where M is the molecular mass, α varies from 0.5 to 1). In the same set of isomers, T
m
and T
b
often change in different succession. To explain the observed trends, a local van der Waals field U that acts on a molecule in a solid or liquid phase, was represented by a sum of an averaged long-range field U
0 from all molecules, and a short-range “contact” term W determined by a molecular shape. Variations of T
m
and T
b
among closely related substances correspond to different strength of perturbation of U
0
(C) (in a crystal) and U
0
(L) (in a liquid) by W. Higher T
b
of isomers with medium-symmetry molecules (like 1,2-disubstituted benzenes and cyclohexanes) reflect the better fitting of their molecules to a local molecular environment in
a liquid (that contains vacancies). Highly symmetrical quasispherical molecules (e.g., C2Cl6 or C6F12) produce a stabilised solid and destabilised liquid state, hence their molecular crystals easily sublime rather than melt
at ambient pressure.
Dedicated in memory of Professor Petr M. Zorky 相似文献
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A melting point measurement facility for the UK has been developed and accredited to ISO/IEC 17025 Calibration status for
the determination of the liquefaction temperature of pure substances from 35 to 250°C.
The facility is based upon a commercial instrument, i.e. an oil bath fitted with an aluminium block (Isotech, model 798 EHT),
a precision multimeter (Isotech TTI-7), a thermocouple directly inserted in the sample under investigation and a platinum
resistance thermometer (PRT) tracking the block temperature. The homogeneity of temperature bath/block was investigated and
the PRT used for the traceability of the measurements was calibrated by NPL and traceable to ITS-90. The process was validated
using four current LGC Certified Reference Materials (CRMs):
相似文献
• | Phenyl salicylate; material number: LGC2411, batch number: 001; liquefaction point: 41.85±0.05°C |
• | 4-Nitrotoluene; material number: LGC2401, batch number: 007; liquefaction point: 51.71±0.21°C |
• | Benzoic acid; material number: LGC2405, batch number: 005; liquefaction point: 122.37±0.21°C |
• | Carbazole; material number: LGC2409, batch number: 007; liquefaction point: 245.58±0.07°C |
• | Different approaches were used to identify reproducible features of the melting point (time-temperature) curves of these four CRMs. Excellent correlation was observed between the certified values for the liquefaction point of the four CRMs and the temperature at the end of their respective melting point curve plateau, determined using a temperature differential approach. An uncertainty budget was derived and the expanded uncertainty at the 95% confidence interval (k=2) was found to be |
• | Phenyl salicylate: ±0.20°C; 4-Nitrotoluene: ±0.17°C; Benzoic acid: ±0.24°C; Carbazole: ±0.27°C |