查询词典 catalyst

After the oxidative polymerization of DMP,styrene was in-situ polymerized under the initiation of dibenzoyl peroxide and dicumyl peroxide,finally thermodynamically compatible PPO/PS alloy was prepared.When styrene content was 50 wt%,for the synthesized PPO/PS alloy the yield and the weight-average molecular weight were determined to be 95%and 1.7×10~5 for PPO,93%and 2.0×10~5 for PS,respectively.The influence of the concentration of DMP and catalyst,molar ratio of N/Cu, oxygen partial pressure,NaOH concentration and temperature on the initial polymerization rate(R_0) of DMP was studied.It was found that the initial polymerization rate of DMP increased with the concentration of DMP and catalyst. The initial polymerization rate increased with the molar ratio of N/Cu at first and then decreased.

通过测定DMP氧化聚合过程中氧气吸收量随时间的变化，研究了DMP和催化剂浓度、N/Cu摩尔比、氧气分压、氢氧化钠浓度及温度对水介质中DMP氧化聚合初始速率的影响，发现DMP氧化聚合初始速率与氧气分压的0.1次方成正比；DMP氧化聚合初始速率随DMP和催化剂浓度及温度的增加而增加；随氢氧化钠浓度和N/Cu摩尔比的增加DMP氧化聚合初始速率先增加后降低。

Single-component samarium diiodide catalyst system was first used with polymerization of acrylonitrile. Adding of hexamethylphosphoramide could greatly improve reaction activity of the catalyst system. AN/Sm12 and l{IVIPA1 Sm12 molar ratios, reaction time and temperature were mainly investigated with yields and molecular weights of resultant PAN.

研究发现HMPA的加入可以极大地提高催化活性；考察了单体与催化剂(SmI2)的摩尔比例、第二组分与催化剂(SmI2)的摩尔比例、反应温度、反应时间等因素对相应聚合物的产率和分子量的影响，通过对聚合物的红外和核磁的分析，提出了&单电子转移-双阴离子引发&机理。

The disubstituted ureas and the catalyst could be separated by addition of water and the catalyst could be reused without deactivation.

新型高效的菲咯啉钯-离子液体含氮化合物羰化催化剂体系，以苯胺为反应物时该体系的转化频率可以达到6000mol/mol/h；氢氧化铯-离子液体催化剂体系，可以在不加入化学计量脱水剂的条件下活化二氧化碳与脂肪族胺反应得到二取代脲，反应结束后可以通过加入水实现产品和催化剂体系的分离，催化剂体系可以重复使用。

It showed that the ammonium ferric sulfate dodecahydrate was an excellent catalyst,the yield of the n-butyl lactate could reach over 95.0% under molar ratio of n-butyl alcohol and lactic acid 2.25∶1,the reaction temperature of 110～125℃,reaction time of 1.5 h and amount of the ammonium ferric sulfate dodecahydrate catalyst of 2.5%.

实验表明：NH4Fe(SO4)212H2O是合成乳酸正丁酯的良好催化剂。最佳反应条件为：醇酸物质的量比2.25∶1，催化剂的用量为反应物料总量的2.5％，酯化反应时间为1.5 h，反应温度110～125℃，酯化率可达95.0％。

The process industrial synthsis of tert-dodecyl mercaptan from dodecylene and hydrogen sulfide with aluminium trichloride as catalyst was introduced, which consists of four units including the preparation of catalyst, purification of raw dodecylene, additive reaction and separation of reaction product.

介绍了以无水三氯化铝络合物为催化剂，十二烯和硫化氢直接加成法生产叔十二烷基硫醇的工业试验工艺。

To improve the selectivity, the Co/Mn/Br catalyst system with ethanal as an additive was studied and the reaction conditions were also optimized, which were as follows:the amount of ethanal 10%(mole ration base on the substrate), reaction temperature 100℃,reaction time 30min,the oxygen pressure 0.2MPa, the amount of the composite catalyst Co/Mn/Br 7%,the mass ration of different ingredients 2:2:1. Under these conditions, the yield comes to 24.10% and the selectivity reaches 75.03%.

为了提高反应的选择性，论文初步研究了以乙醛作为添加剂条件下各工艺参数的影响，并进行正交优化，得出最佳条件为：乙醛加入量1：10，反应温度100℃，反应时间30min，氧气压力0.2MPa， Co/Mn/Br混合催化剂加入量7%，质量比2：2：1，在此条件下，反应产率为24.10%，选择性可达75.03%。

The catalytic performance of all the amorphous alloy catalysts mentioned above was measured during liquid phase hydrogenation of furfural to furfuryl alcohol, together with the kinetic studies. The relationship between the catalyst performance and the structure of catalyst, surface electronic state of the amorphous alloy has been systematically studied based on a series of characterization of catalysts . Meanwhile, the promoting effects of the support on the thermal stability and catalytic activity of the amorphous alloy catalysts have been discussed.

本文采用一系列的表征方法(XRD、XPS、TEM、BET、氢吸附、TPD等)进一步研究非晶态合金催化剂的表面结构、表面电子态和催化性能之间的关系，探索电子效应和几何效应对催化剂活性中心结构的影响，探索非晶态合金的晶化失活和载体对非晶态结构的稳定化作用，以及修饰剂对催化性能的改善作用等。

The THFA yield and selectivity were 2.0%higher than those by using catalyst Ⅰ without promoter,3.0%higher than those by using Raney nickel catalyst under the same reaction conditions and furfuryl alcohol conversion.

在相同反应条件和糠醇转化率条件下，四氢糠醇收率和选择性均比没有助剂的镍催化剂Ⅰ高2.0%，比骨架镍催化剂高3.0%。

Firstly, D,L-lactide was synthesized from D,L-lactic acid with zinc powder as catalyst,and glycolide from glycolic acid using Sb2O3 as catalyst.

首先以乳酸为原料，锌粉为催化剂合成了丙交酯；以乙醇酸为原料，三氧化二锑为催化剂合成了乙交酯。

Nano-TiO2/SiO2 was used as catalyst to investigate the influence of different calcined temperatures on the photocatalytic activity of the catalyst for the photocatalytic degradation of heptene.

以TiO2/SiO2纳米粒子为催化剂，研究了催化剂不同焙烧温度对二氧化硫与庚烯光催化反应的影响。

There are different types of personal loans available.

有许多不同类型的个人贷款优惠。

The above mentioned teaching model of spiral rising can be used to avoid rigidness in teaching.

上述螺旋式上升的教学模式，可以避免教学形成模式後的僵化现象。