查询词典 catalysts

Therelationship of the amount of catalyst and the ee% of product was seen to be negative nonlin-ear. Catalyst 3 was used in the enantioselective addition of diethylzinc to aromatic aldehydesand gave good results. The configuration of products was determined by the configuration ofthe catalysts' chiral carbon linked with hydroxy group. Using β- amino alcohols bearing only one chiral center as catalysts for the enantiose-lective addition were studied. D-N, N-dialkyl-2-amino butanol gave poor catalytic effect be-cause of their structure. The configuration of the product is the same as the catalyst. Anotherkind of β- amino alcohols - phenylglycine derivatives and valine derivatives have chiralcenter on the carbon linked with amino group. Catalyzed by-phenylglycine derivatives 6,7, 9, 10, the reactions gave satisfied results. The optical yields exceeded 80%.

在探讨了含有两个手性中心的β-氨基醇之后，选择了只有一个手性中心的β-氨基醇，一是手性中心为连羟基的手性碳原子：D-N，N-二烷基-2-氨基丁醇；二是手性中心为连氨基的手性碳原子：D-苯基甘氨酸衍生物和L-缬氨酸衍生物。D-2-氨基丁醇的催化效果不太好，这与其结构的空间位阻较小有关系，反应产物与连羟基手性碳构型一致；由苯基甘氨酸和缬氨酸出发合成五种β-氨基醇6-10，研究了不同ee％的-6作用下的二乙基锌-苯甲醛加成反应，发现该催化剂具有不对称放大效应；-7，9，lO的催化效果也比较令人满意，光学产率80％以上，所得产物构型与催化剂构型一致。

Catalysts in three synthesis routes,the hydroxylation of 4-tert-butyl-phenol,the alkylation of pyrocatechol by tert-butyl alcohol and the alkylation of pyrocatechol by isobutene,were discussed in detail in terms of reaction conditions,catalysts,temperature,reaction time etc.

论述了对叔丁基苯酚羟基化法、邻苯二酚与叔丁醇烷基化法和邻苯二酚与异丁烯烷基化法生产对叔丁基邻苯二酚的合成路线的催化剂。

The structure of the catalysts has been investigated by XRD technique and the effect of thermal treatment on the reducibility of the catalysts by TPR technique.

用XRD研究了不同Ag含量催化剂的结构变化情况，利用程序升温还原技术考察了热处理温度对催化剂还原性能的影响。

A lot of work have to be done in modification of ruthenium catalysts before the "precious-metal" catalysts become commercially feasible.

由于钉的稀有和昂贵，要在工业上广泛应用，还需要做大量的研究。

PO〓 was used as promote for the V〓O〓/SiO〓 or MoO〓/SiO〓 catalysts, which exists in tetrahedral symmetry on surface of catalysts and form to P-O-M bond.

PO〓在催化剂表面以四配位形式存在，通过与金属氧化物形成P-O-M键，可降低催化剂中M〓的Lewis酸强度。

The catalysts such as tetraphenyl tin,aluminium isopropoxide and boron trifluoride etherate complex were used to catalyze the copolymerization.In addition,the copolyester can be given by copolycondensation after monomers were hydrolyzed by phosphoric acid.Boron trifluoride etherate complex was chosen as the catalyst because the catalytic activity was the best among the catalysts.

由于γ-戊内酯为五元环结构，难以进行开环聚合，因此分别考察了四苯基锡、异丙醇铝、三氟化硼乙醚络合物等催化剂，以及以磷酸为催化剂的水解缩聚反应，结果发现三氟化硼乙醚络合物的催化活性最高，因此选择三氟化硼乙醚为本体开环聚合的催化剂。

Characterization of the catalysts indicates that the Cu species is more stable in the VCe1-xCux-NaCl than those in the supported catalysts, and the reduced copper species with low valance might be the active sites.

通过各种表征手段表明，在复合氧化物中铜物种能够以孤立的状态稳定存在，经过还原后，还原态的低价态铜物种可能是反应的活性中心。

In order to study the effects of acid catalysts on wood liquefaction in phenol, the liquefaction of wood powder from Chinese fir and poplar in the presence of phenol using several relatively weak acids as catalysts, such as phosphoric acid (85%), sulfuric acid (36%), hydrochloric acid (37%) and oxalic acid (99%), were investigated.

为了探讨酸性催化剂对木材苯酚液化的影响，该研究采用磷酸(85%)、低浓硫酸(36%)、盐酸(37%)、草酸(99.5%)4种弱酸性无机酸，在不同温度下进行了木材的液化试验。

Instructed by this method, the structure-reactivity relation of the oxidation reaction catalysts was found and a way was proposed to enhance the catalytic ability of traditional acetylacetone catalysts by supporting them on ionic liquid.

在该方法的指导下，发现了氧化催化剂结构活性关系，提出了一套用离子液体支载来提高乙酰丙酮金属催化剂催化氧化活性的方案。

This paper contains three parts: 1 Synthesis of novel titanium complexes; 2 Polymerization behaviors of alkoxyl substituted Cp Titanocenes as catalysts for styrene syndiotactic polymerization; 3 Polymerization behaviors of alkenyl substituted Cp Lanthanocenes as Methyl Methacrylate polymerization catalysts.

中文题名新型茂钛、噁唑啉钛络合物的合成、表征以及茂钛、茂稀土络合物催化性能的研究副题名外文题名 Synthesis，characterization of novel Cp，oxazoline titanium complexes and polymerization behaviors of titanocenes and lanthanocenes 论文作者张浩导师钱延龙黄吉玲学科专业应用化学研究领域\研究方向金属有机与均相催化学位级别博士学位授予单位华东理工大学学位授予日期2003 论文页码总数148页关键词金属有机化学稀土络合物噁唑啉类钛络合物茂钛络合物馆藏号BSLW /2003 /O627 /27 本论文包括三部分内容：1）有机金属钛络合物的合成；2）烷氧基取代茂钛络合物催化苯乙烯间规聚合的研究；3）烯基取代茂稀土络合物催化甲基丙烯酸甲酯聚合的研究。

With Death guitarist Schuldiner adopting vocal duties, the band made a major impact on the scene.

随着死亡的吉他手Schuldiner接受主唱的职务，乐队在现实中树立了重要的影响。

But he could still end up breakfasting on Swiss-government issue muesli because all six are accused of nicking around 45 million pounds they should have paid to FIFA.

不过他最后仍有可能沦为瑞士政府&议事餐桌&上的一道早餐，因为这所有六个人都被指控把本应支付给国际足联的大约4500万英镑骗了个精光。