查询词典 catalyst

After pretreating of carrier by vapour the catalytic performance of this catalyst was improved.The products have better viscosity and lower bromic bond when the new catalyst has been used.The products are good base oil for producing high quality lubricating oil.

同时载体经水蒸气预处理，酸性有所变化，催化剂的各项性能均有显著的提高，产品具有较好的粘度和较低的溴价。

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。

Stannous caprylate was selected as the catalyst. Under certain vacuum, we investigate the relation of both the dose of catalyst, the temperature of reaction, the time of reaction and the molecular weight of the PLA.Furthermore we investigate how the purity of lactide and the circumstance of vacuum affect the molecular weight of the PLA.

实验中选用辛酸亚锡Sn(oct_2为催化剂，在一定的真空度下考察了催化剂用量、反应温度、反应时间与聚乳酸分子量的关系；并考察了丙交酯纯度及真空度对聚乳酸分子量的影响。

The effect of zeolites ion-exchanged by transition metals on thermal catalytic cracking reaction is studied. The product distributions of the cracking reactions catalyzed by theβor ZSM-5 zeolites exchanged with transition metals are different from that catalyzed by corresponding Hzeolites, which means the mechanism of cracking reactions has varied. Group Ⅷ metals Fe, Co, Ni and Cu, Zn are shown to be of strong catalytic activity of oxidative dehydrogenation, while Ti and Cr are not of oxidative activity. Catalyzed by zeolites or catalyst containing Ag, conversion of thermal catalytic cracking reactions and the yield of ethylene increase while the yield of propylene does not decrease. Silver can not only promote the formation of carbonium ion, but also convert carbonium ion into free-radical via redox reaction. The weak adsorption of olefins on silver reduces the occurrence of hydrogen transfer and dehydrogenation. As a result, the yield of light olefins is favored by silver in the catalyst.

采用过渡金属交换的分子筛作为催化剂，进行催化热裂解制取乙烯的反应，研究发现，在β沸石分子筛和ZSM-5分子筛中引入过渡金属后，催化热裂解反应的产物分布与相应的氢型分子筛相比有了较大的变化，说明过渡金属的加入对于催化热裂解反应的机理具有影响，Ⅷ族金属如Fe、Co、Ni和第Ⅰ、Ⅱ副族Cu、Zn表现出较强的氧化脱氢活性，产物中氢气、焦炭的产率很高，Ti、Cr则未表现出氧化作用：分子筛及催化剂中引入银后，催化热裂解反应的转化率和乙烯的产率有了提高，丙烯产率没有很大的变化，说明银在催化热裂解反应中能够促进正碳离子的生成，又有可能通过氧化-还原作用部分改变反应机理，促进了自由基的生成，并且由于银对烯烃的吸附很弱，其氢转移反应和脱氢、加氢活性比较低，有利于烯烃产率的提高。

The influence of reaction condition on the yield of isopropyl chloroacetate as investigated such as catalyst loading, molar ratio of chloracetic acid to isopropanol, reaction time and repeated use of the catalyst.

考察了催化剂的用量、反应物物质的量比、反应时间和催化剂的重复使用等因素对收率的影响。

In this paper, the applications of the environmental friendly solid acid catalysts for esterification were studied and the activities of these catalysts were discussed, by which the solid acid ferric sulfate x-hydrate was used first as catalyst in the synthesis of dimethyl fumarate and ethyl chloroacetate and solid super acid SO42-/Fe2O3 was used first as catalyst in the synthesis of ethyl p-nitrobenzoate.

本文研究了对环境友好的固体酸催化剂在酯化反应中的应用，首次以固体酸Fe_2(SO_4)_3·xH_2O为催化剂合成了新型防霉剂富马酸二甲酯和化工原料氯乙酸乙酯，以固体超强酸5O_4~(2-)／Fe_2O_3为催化剂合成了医药中间体对硝基苯甲酸乙酯，并探讨了这些催化剂的催化活性。

A mathematical model is established, which considers multicomponent diffusion, chemical reaction, pore size distribution of the catalyst and capillary condensation of condensable components within the catalyst pellet.

将多组分扩散、化学反应、催化剂孔径分布以及反应组分在催化剂内部的毛细冷凝等因素结合在一起，建立了描述催化剂处于内部部分润湿状态下的反应动力学的数学模型。

As hydrogen atoms and catalyst atoms are normally found bound together as molecules or are bound in other compositions of matter, BlackLight has invented a solid fuel that uses conventional chemical reactions to generate the catalyst and atomic hydrogen at high reactant densities that in turn controllably achieves very high power densities.

通过分离出该进程中的能量产物，用外界元素中电解水。使用水作为燃料，不可见光发电机的可用成本是不昂贵的，而且，他不会带来空气污染或者放射性废物，还具有商业使用价值的氢成分作为氢产物。

The explanation for this is that ethylene oligomerized in the Ni catalyst active site and the oligomers containing vinyl end group served as comonomers to in situ copolymerize with the growing polyethylene chain in the active site of titanium catalyst.

催化剂的摩尔比、Al/摩尔比和聚合温度等聚合条件对催化活性及聚合物的结构与性能有明显影响。

The new preparation method of catalyst soak precipitation method is originated Used of new surfactant APG as a assistants, mixed salt soak sotution and coprecipitant with low surface tension and strong permeate and weted force coprecipitate active composition to the inner micropore of prepreparated supporter with hight mechanical strength and large pore diameter This method solve the problem of the low mechaniceal strength of coprecipitated catalyst.

开创了一种新的催化剂制备方法。

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。