查询词典 Chain Reaction

The factors which affect the average molecular weight of the polymer of AM and DMDAAC were investigated. The optimal reaction conditions are as follows: the concentration of monomer AM was 30%, while DMDAAC was 5%; the reaction temperature was 30℃, the amount of initiators at the low temperature stage was 0.05‰(compared to the weight of the monomers joining the polymerization), while V-50 was 0.025‰, the weight ratio of potassium persulphate to sodium bisulphite is 1:1, the amount of carbamide was 40‰, and complexing agent was 0.05‰, besides, aerate nitrogen gas for 8min, then the high molecular weight polymer (M=1.217×10^7) could be got after 16h reaction.

研究了影响AM与DMDAAC共聚物的平均分子量的因素，得到了优化条件为：单体浓度为30%，DMDAAC与AM摩尔比为5：95，聚合温度为30℃，低温段引发剂用量为0.05‰，K2S2O8与NaHSO3质量比为1：1，偶氮二异丁基脒盐酸盐(V-50)用量为0.025‰，尿素用量为40‰，乙二胺四乙酸二钠(EDTA-2Na)用量为0.05‰，在此优化条件下聚合反应16h后得到分子量为1.217×10^7的阳离子型聚丙烯酰胺。

The optimal measuring conditions were investigated. The results indicated that the catalytic reaction to Pt and bromocresol purple was the first-order reaction. The apparent activation energy was 217.4kJ/mol and the maximum absorption wavelength of fading reaction was at 434 nm. The linear range of Pt was 0.16-4.0μg/L and the detection limit was 2.5×10^(-11)g/mL. Most of common ions had no interference with the determination, while ten multiples of Ru, Rh and Os had interference with the determination of Pt. Therefore.

选择了最佳测定条件，实验结果表明，催化反应对铂和溴甲酚紫为一级反应，反应的表观活化能为217.4kJ/mol，褪色反应的最大吸收波长为434nm，方法测定R哪的线性范围为0.16~4.0μg／L，检出限为2.5×10^(-11)g/mL，大多数常见离子不干扰测定，10倍以上的Ru，Rh和Os对测定有干扰，可在测定前分离除去。

The structural and photocatalytic properties of TiO〓 as well as surface acidity were greatly improved by sulfation. SO〓〓/TiO〓 solid superacid with Hammett constant Ho less than -12.14 was prepared by treating the TiO〓 with 1.0mol. L〓 sulfuric acid solution and then calcining at 450℃ for 3h. When compared to unmodified TiO〓, the SO〓〓/TiO〓 superacid catalyst exhibited higher anatase content, smaller crystal size, higher specific surface area, centralized pore size distribution, and the blue-shifted band edge of uv-vis adsorption spectra. Furthermore, the SO〓〓/TiO〓 superacid also showed excellent reaction activity and stability for CH〓Br photocatalytic decomposition even under the moist reaction conditions. The apparent quantum efficiency of SO〓〓/TiO〓 was 10 times of that of TiO〓 catalyst for the photocatalytic degradation of bromomethane. Therefore, the SO〓〓/TiO〓 superacid catalyst is promising for practical application in environmental remediation.It was found that both L and B acid sites exist on SO〓〓/TiO〓 photocatalyst while only L acid sites on TiO〓 photocatalyst. On the basis of experimental results, the synergistic model of superacidic centers was proposed for SO〓〓/TiO〓 photocatalyst to explain the photocatalytic behavior and the mechanism of superacidifing effects, assuming that the adjacent L and B acid sites induced by SO〓〓 comprise cooperatively the superacidic center on superacid photocatalyst. The group cooperation of the superacidic center could strengthen the surface acidity, increase surface acid sites and the adsorbtion of O〓, promote separation of photogenerated electron-hole pair, enhance the interfacial transfer of charges and reversibility of water adsorption. Consequently the excellent photocatalytic activity, reaction stability and resistibility to humidity of SO〓〓/TiO〓 superacid photocatalyst may attributed to the group cooperated effect of the superacidic center on the photocatalyst.

研究结果表明：SO〓〓与TiO〓表面的结合为螯合式双配位结构；TiO〓光催化剂表面经H〓SO〓浸渍处理后，提高了表面酸性，改善了催化剂结构和光催化性能，当H〓SO〓浸渍浓度为1.0mol.L〓、烧结温度为450℃时，可制得SO〓〓/TiO〓超强酸催化剂(H〓＜-12.14)，其结构和光催化活性得到明显改善，与TiO〓相比，SO〓〓/TiO〓光催化剂的锐钛矿含量高、晶粒小、BET比表面积大、孔径分布集中、光谱吸收边蓝移，具有优异的光催化氧化活性、稳定性及抗湿性能，光催化降解溴代甲烷的表观量子效率比TiO〓催化剂提高了一个数量级，是一种有实际应用前景的高效光催化剂；由此提出了SO〓〓/TiO〓超强酸催化剂表面集团协同作用的超强酸中心模型，认为在SO〓〓/TiO〓超强酸催化剂表面，由SO〓〓诱导的相邻L酸中心和B酸中心组成了集团协同作用的超强酸中心，其集团协同作用显著地增强了催化剂表面酸性、增大了表面酸量及O〓吸附量、促进了光生电子和空穴的分离及界面电荷转移，具有可逆吸附水的性能，是SO〓〓/TiO〓超强酸催化剂具有优异的光催化氧化活性、很好的活性稳定性及抗湿性能的重要原因。

In this paper isopropyl -γ- chlorobutyrate was prepared from γ- butyrolactone by one - step. The effects of molar ratio of reactants, reaction temperature, reaction time on the yield of product were discussed, the optimum reaction condition was obtained.

一氯代丁酸异雨酯是合成新型拟除虫菊酯中间体环丙烷较酸及高效抗菌新药丙氟见酸和环丙氟院酸中间体环丙胺的重要原料［''］。

It was increased ethyl hexanoate synthesis substrate concentration mediated by Rhizopus chinensis 2113 whole-cell lipase after improved synthetic activity and optimized reaction condition. The reaction condition were: caproic acid concentration 2.4mol/L, substrate molar concentration ratio 1:1.1, initial water content ≤0.2%, lipase water activity 0.3~0.66, enzyme amount 16%, reaction temperature 30℃, agitation speed 150 r/min.

通过合成酶活的提高及反应条件的优化，提高了华根霉2113全细胞脂肪酶催化己酸乙酯合成的反应底物浓度，其反应条件为：己酸浓度为2.4mol/L；酸醇摩尔浓度比1：1.1；反应体系含水量≤0.2%；脂肪酶水活度0.3～0.66；加酶量16%；反应温度30℃；150r/min振荡反应。

The results show that isobutene oligomerization is fast liquid-solid reaction. Under the temperature of 80 ℃～120 ℃ and pressure of 2.0 MPa, the products of oligomerization are mainly dimers and trimers of isobutene. The yield of trimers is higher than that of dimers and the mass fraction of trimers decreases with reaction temperature increasing. The yield of tetramers is much lower than that of dimmers and trimers. The tetramers are formed by reaction of isooctenes and C8 carbonium ion.

结果表明，异丁烯齐聚反应为快速液固相催化反应，在80 ℃～120 ℃，2.0 MPa的实验条件下，反应产物主要是异丁烯的二聚物和三聚物，且三聚物的收率远高于二聚物，两者的浓度比值随反应温度的升高而下降；少量四聚物的生成主要源于碳八烯烃与碳八正碳离子的反应。

The experiments for determining the mechanism and kinetics of catalytic pyrolysis reaction for a simple petroleum feedstock, were carried out in a batch micro-reactor using Daqing light gas oil. The results showed that carbonium and free radical reactions were the key reactions in catalytic pyrolysis. The carbonium ions were induced by catalytic reaction, whereas free radical reaction was predominantly due to thermal cracking.

首先在重油微反装置上考察大庆减压馏分油催化裂解反应产品分布，并将反应结果与相同温度范围内的热裂解反应相比较，二者的产品分布随温度等操作参数的变化规律明显不同，进而推断催化裂解反应过程为正碳离子反应机理和自由基反应机理并存；并建立了大庆减压馏分油催化裂解消失动力学模型，求得了化学反应速率常数。

To be different from the already chloromethylation catalyst, it has a certain amount of moisture wet, which will not produce huge amounts of doughtic cancerogenic chloromethyl methyl ether during and after the reaction.4,4\'-bisbiphenyl, 1,4-bisbenzene, 1,4-bis(chloro- methyl)-2,5-dimethylbenzene, 1,5-bis-2,4-dimethylbenzene, 4-(chlor- omethyl)-1,2-dimethylbenzene, 1,2-bis-4,5-dimethylbenzene, 5,8-bis-1,2,3,4-tetrahydronaphthalene, 3,3\',5-tris-4,4\'-bisbiphenyl and 3,3\', 5,5\'-tetrakis-4,4\'-bisbiphenyl were synth- esized by using this new catalyst. Results indicated that when the reaction temperature was 55～60℃, the reaction time was 12h, the catalyst which consists of the concentration of 80%H_2SO_4, HAc and Lewis acid, the amount of Lewis acid 0.15 mol(nLewis:nbiphenyl=1.5:1), yield of biphenyl chloromethylation product 4,4\'-bis(chrolomethylbiphenyl can reach a maximum 85%.

采用这种催化体系完成了4，4′-二氯甲基联苯、对二氯甲基苯、1，4-二氯甲基-2，5-二甲基苯、1，5-二氯甲基-2，4-二甲基苯、4-氯甲基-1，2-二甲基苯、1，2-二氯甲基-4，5-二甲基苯、5，8-二氯甲基-四氢萘、3，3'，5-三氯甲基-4，4'-二甲基苯和3，3'，5，5'-四氯甲基-4，4'-二甲基苯的合成，结果表明：在反应条件为：反应温度55～60℃，反应时间12h，选择80%H_2SO_4、冰醋酸和Lewis酸为催化剂，反应最佳反应Lewis酸用量是0.15mol(和原料比为1.5：1)，反应效果最好，联苯氯甲基化产物(4，4′-二氯甲基联苯)收率为85%；在反应条件为：反应温度70℃，反应时间8h，80%H_2SO_4、冰醋酸和Lewis酸为催化剂，反应最佳反应Lewis酸用量是0.1mol(和原料比为1：1)时，反应效果最好，苯的氯甲基化产物收(来源：ABd0C论文eded网www.abclunwen.com)率为75%；在反应条件为：在反应条件为：反应温度40℃，反应时间10h，60%H_2SO_4和Lewis酸为催化剂，反应最佳反应Lewis酸用量是0.1mol(和原料比为1：1)时，反应效果最好，对二甲苯氯甲基化产物(1，4-二氯甲基-2，5-二甲基苯)收率为78.5%；在反应条件为：反应温度35℃，反应时间10h，60%H_2SO_4、冰醋酸和Lewis酸为催化剂，反应最佳反应Lewis酸用量是0.1mol(和原料比为1：1)时，反应效果最好，间二甲苯氯甲基化产物(1，5-二氯甲基-2，4-二甲基苯)收率为81.5%。

Analyse and compare what adopt a variety of pair of methods, the Michael addition reaction of ester of acerbity second of second of hydroxyl of protection of benzyl of the response of close nucleus addition that uses second nitrile and ester of formic acid second certainly, chloridize, cyanogen, reaction that take off carboxyl generates 3- benzyl oxygen radical the fifth of the ten Heavenly Stem the method of 2 nitrile, detailed discussion the action that wait and the by-product that arise possibly reach the reactant in each pace reaction, activator, dissolvent avoid a method.

通过对多种方法的分析和比较，确定采用乙腈和甲酸乙酯的亲核加成反应、氯化苄保护羟基、氰乙酸乙酯的Michael加成反应、脱羧反应生成3-苄氧基戊二腈的方法，并具体的讨论了每一步反应中反应物、催化剂、溶剂等的功能和可能产生的副产物及避免方法。

The result shows that the best reaction conditions for synthesizing CMC with a high degree of substitution (1.68) are that the ratio of chitosan to sodium chloroacetate is 1:5, reaction temperature is 90℃, reaction time is 5h, and the amount of catalyst is 3%.

研究了投料比、反应温度、反应时间、催化剂等单因素对取代度的影响，合成高取代度的最佳反应条件为m：m=1：5、温度90℃、时间5h、催化剂量为3%，可制得取代度为1.68的羧甲基壳聚糖。

The receding calculations and experiment analyses in this subject are built on the blood cast of pig tongue.

本研究课题的前期工作是采用猪舌血管铸型模拟人舌而进行的数值计算与实验分析。

"Each human infection constitutes an opportunity for genetic modification of the virus through reassortment, mutation, or both...."

&每一次人类的感染都暗藏着一次基因修改的机会，无论是通过病毒的整合、突变或者兼而有之。。。。&