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采用密度泛函理论中的B3LYP方法研究了气相中过渡金属La在二、四重态势能面上催化C2H4的反应机理。全参数优化了二、四重态势能面上各个驻点的几何构型,同时对过渡态进行了频率分析,使用内禀反应坐标(IRC)方法验证了过渡态的准确性,通过AIM理论和NBO分析方法对主要的驻点进行了键分析,并对2IM1、2IM3进行了态密度分析。结果表明:La与C2H4的反应存在两种可能的路径,反应在二重态势能面上进行且均为放热反应。键分析表明初始复合物中La与C2H4分子之间为共价作用。 相似文献
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漆酚钼螯合高聚物的合成及表征 总被引:13,自引:3,他引:10
采用漆酚与四氯氧化钼反应制得兼具螯合物特点和生漆固有性能的漆酚钼螯合高聚物 (PUM) .对不同反应条件下制备的高聚物的含钼量进行了测定 .并通过元素分析、红外光谱、电子顺磁共振谱、光电子能谱、质谱、高效液相色谱和热失重分析探讨高聚物的生成过程、结构特征和热性能 .结果表明 ,漆酚与四氯氧化钼首先发生氧化还原反应和配位反应生成螯合物 ,然后进一步聚合成为高聚物 ;该高聚物中存在漆酚钼螯合物结构单元且具有很好的热稳定性 ,其耐热性能比生漆和传统黑推光漆好得多 . 相似文献
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Chung-Jen Wu Chuh-Yung Chen Eamor Woo Jen-Feng Kuo 《Journal of polymer science. Part A, Polymer chemistry》1993,31(13):3405-3415
Maleation of a thermoplastic elastomer, styrene-[ethylene-butylene]-styrene (SEBS) triblock copolymer, was carried out by a solution grafting reaction with maleic anhydride initiated by dicumyl peroxide. The reaction products from the graft reaction in xylene, commonly chosen as the solvent for maleation graft reactions, were identified using liquid chromatograph (LC), IR, and 13C-NMR. Side products from the graft reaction were identified by the LC analysis and, it was concluded that xylene affected the graft reaction through its active methyl groups. Reaction mechanisms were investigated by performing free radical kinetics analysis. The reaction orders and the apparent rate constant were estimated. It was concluded that a proper choice of the solvent might favor better graft efficiency. © 1993 John Wiley & Sons, Inc. 相似文献
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The mechanism of collision reaction among protons, N2 and water vapor was theoretically studied using Density Functional Theory. The geometries of reactants, transition states, intermediates and products were optimized at the B3LYP/6-311 G^** level by the BERNY gradient analysis method. Transition states and intermediates have been identified by vibrational frequency analysis. The relationship among reactants, intermediates, transition states and products was affirmed by IRC calculation. The variations of energy and geometry along the IRC-determined reaction paths were described. The possible reaction pathways were represented and the optimal one was decided from the viewpoint of energy. 相似文献
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Liana Fanurovna Nurislamova Irek Marsovich Gubaydullin 《Journal of mathematical chemistry》2017,55(9):1779-1792
This paper proposes a procedure for simplifying the mathematical model of a chemical reaction by reducing the number of steps and species in the reaction scheme. This procedure is based on the sensitivity analysis of the model functional to the change in the model parameters. The application of this procedure makes it possible to accelerate and improve the construction of mathematical models for chemical reactions, as this does not require the calculation of sensitivity coefficients at various time points or sensitivity matrix analysis. This scheme was predicted the same behavior of the main reaction components as the detailed reaction scheme but includes much fewer steps. The efficiency of using this procedure was demonstrated by comparative results of modeling of formaldehyde oxidation and hydrogen oxidation in terms of detailed and reduced schemes. The sensitivity analysis was performed by Sobol’s method. 相似文献
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金属醋酸盐催化合成聚丁二酸乙二醇酯预聚体和碳酸二甲酯 总被引:3,自引:0,他引:3
研究了醋酸盐催化碳酸乙烯酯(EC)和丁二酸二甲酯(DS)同时合成聚丁二酸乙二醇酯 (PES) 预聚体和碳酸二甲酯(DMC)的耦合反应新工艺。 采用气相色谱-质谱联用定性分析馏分组成;红外光谱、核磁共振表征了预聚物的结构;采用乌式粘度计测试了预聚物的特性粘数;气相色谱定量测定馏分碳酸二甲酯的收率以考察耦合反应的进度。 以对该反应催化效果最佳的无水醋酸锂为催化剂考察了物料配比、反应温度、反应时间、催化剂用量对耦合反应的影响,结果表明,最佳的工艺条件为:反应温度195~200 ℃,n(EC)∶n(DS)=2∶1,n(cat)∶n(EC+DS)=0.02∶1,反应时间为2 h,耦合反应所得的DMC收率为48.0%,聚丁二酸乙二醇酯预聚物的特性粘数为0.3787。 相似文献
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Xiaoliu Li Yongmei Wang Daming Du Zhong Wen Guoxiang Xiong Jiben Meng 《中国科学B辑(英文版)》1997,40(3):270-277
Solid state Michael addition reaction of indole with α, β-unsaturated carbonyl compounds was carried out, by which a series
of compounds containing three different heterocyclic groups binding to one carbon atom were ob-tained. In the presence of
Lewis acid, indole could undergo the solid state condensation reaction with aromatic ketones and aldehydes or quinones. The
solid state reaction showed higher selectivity and yield than solution reaction. The structures of products were identified
by IR,1H NMR, MS. elemental analysis and X-ray crystal analysis. The reac-tion mechanism was also proposed.
Project supported by the National Natural Science Foundation of China 相似文献
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煤催化气化工艺中碱金属腐蚀刚玉质耐火材料的实验研究 总被引:1,自引:0,他引:1
针对煤催化气化反应器设计中遇到的材料问题,采用碳酸钾及催化气化工况富含碱金属气化灰渣为实验原料,进行了碱金属腐蚀刚玉质耐火材料的实验研究。着重考察了有氧空气气氛和无氧还原性气氛、反应温度、反应时间、碱金属存在形态对腐蚀行为的影响,并结合SEM-EDX、XRD、核磁Al谱等表征手段,研究了反应前后碱金属和刚玉质耐火材料的成分、物相及结构变化。结果表明,碱金属对耐火材料腐蚀行为受反应的温度、气氛、时间及碱金属存在形态等因素影响较大。分析表明,有氧空气气氛下腐蚀尤为严重的原因是,原料中存在的钾与刚玉耐火材料发生化学反应生成新的钾的铝酸盐物相,且其含量随温度升高、反应时间延长而增加。 相似文献
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dppm与CH2Cl2在Pd(OAc)2作用下反应stopped—flow动态学研究 总被引:1,自引:0,他引:1
dppm与CH2Cl2在Pd(OAc)2作用下反应stopped_flow动态学研究韦凤萍黄永仁(华东师范大学分析测试中心上海200061)汪汉卿(中国科学院物理研究所兰州730000关键词动态学Pd(OAc)2dppmCH2Cl2停-流中图分类号O... 相似文献
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高取代度淀粉醋酸酯的制备 总被引:12,自引:0,他引:12
改善淀粉热塑性的方法主要是用塑化剂对其进行处理和用化学方法制备淀粉衍生物,使羟基被长链取代,减弱淀粉分子间的氢键,大分子可在较低温度下运动,从而达到降低熔融温度的目的。近年来,对高取代度淀粉醋酸酯已有报道^[1-5],Sagar等^[2]认为,粉酯的取代度越高,侧链越长,热塑性和亲水性的改变就越明显,而且酯基可起到内增塑作用,可塑性的提高反映在材料的流变学,热学及力学性能的改变上,Maheras等^[3]用高取代度的淀粉醋酸酯和纤维素醋酸酯共混,制成了纤维和塑料制品,由于高取代度淀粉醋酸酯熔点较高,Brochers等^[4]提出通过加入分子量为100-1000的增塑剂,如甘油三醋酯等,可使熔融温度降到150℃左右,Tanaka等^[6]将淀粉和乙烯类化合物在酯化催化剂的作用下反应,得到的淀粉酯性能较为理想,分子量高,具有相当好的机械性能和耐水性,国外专利报道了以甲磺酸(MSA)为催化剂制备淀粉醋酸酯的方法^[7},但对其结构和性能尚未作系统的研究,本文以冰醋酸和醋酸酐为混合酸,MSA为催化剂,制得了具有较高取代度的高直链淀粉醋酸酯,并系统研究了反应温度,反应时间,反应物比例等不同反应条件对取代度的影响,通过红外分析,特性粘度测试,溶解性等分析手段,表征了高直链淀粉醋酸酯的结构与性能。 相似文献
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