催化的
- 与 催化的 相关的网络例句 [注:此内容来源于网络,仅供参考]
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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。
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And the mechanism of ATRP is discussed from the view of complex-catalytic reaction. It is deduced that the active center in ATRP is not pure radical but complex active center, which maybe a complex with radical and complex ion. The structure of active center may have a "bridge"structure formed through propaganating radical and transition metal ion, and the active center exists in a"cage"generated by ligand-transition metal ion-organic halide and monomer or solvent.
论文运用基团贡献理论对一些实验现象和结果进行了讨论和分析,并结合研究结果对络合催化引发原子转移自由基聚合反应的机理进行了初步的探讨,认为:过渡金属化合物与有机配体参与的络合催化引发原子转移自由基聚合反应中,聚合反应的活性中心不是纯粹的自由基活性中心,而是与过渡金属相结合的、有着某种"笼"结构存在的复合式活性中心,同时该活性中心以自由基特性为主,同时兼具某种程度的其它活性中心特征(如阳离子和络合聚合活性中心)。
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SiO〓 crystal transformation was improved by adding Na〓SO〓, alpha cristobalite but not tridymite was catalytic active support. C〓 selectivity was improved by adding W and P, and suppressed deep oxidation property of SiO〓. W-O in catalyst surface was not active species. The support combined with S, W, P show low activity and high C〓 selectivity.
Na〓SO〓的加入促进了SiO〓晶型的转化,α-方石英是催化活性载体成分,而鳞石英没有甲烷氧化偶联反应活性。W和P的加入改善了C〓烃的选择性,抑制了SiO〓的深度氧化特性;W-O物种不是催化活性物种;由S、W、P及SiO〓组成的载体反应活性较差,但选择性较好;同时S元素对C〓烃的选择性的贡献有限。
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Using the one-atom theory, the electronic structures of Pt-electrocatalyst with fcc structure was determined as follows:(5dn)6.48 (5dc)2.02 (6sc)1.48(6sf)0.02. Compared to the result obtained by the first-principle method such as FP-LMTO, CASTEP, their results are in good agreement with each other. Comparing the calculations of physical properties such as lattice constants, cohesive energy and bulk modulus by OA method and first-principle method, the result obtained by OA method is in excellent agreement with experimental value, but the result obtained by first-principle method is not accordable. The relationship between the electronic structures and catalytic performance was explained qualitatively by OA method and first principle method according to its electronic structures. Because the d-orbital vacancies increases and static density is high around Fermi energy band, Pt has good catalytic performance.
摘 要:依据纯金属单原子理论确定面心立方结构电催化剂Pt的电子结构为(5dn)6.48(5dc)2.02-(6sc)1.48(6sf)0.02,与采用第一原理的FP-LMTO和CASTEP等方法所计算的电子结构相比较,其结果非常相近;由OA理论和第一原理方法计算的晶格常数、结合能、体弹性模量等物理参数进行比较,OA理论计算的结果与实验值较符合,而第一原理方法计算的结果与实验值相差较大;在此基础上用OA理论和第一原理方法研究了Pt的电子结构与催化性能的关系,由于d带空穴增多和费米能级附近态密度较高,导致金属Pt的催化性能很好。
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We make chloroacetylaion to N-terminal of Asp, and then convert this compound to GD dipeptide by aminolysis. Followed the lipase -catalyzed peptide synthesis of RGD in aqueous water-miscible organic cosolvent is studied. We set up a new efficient reaction method to synthesize RGD tripeptide. The problem that peptide containing polar amino acid can not be synthesized readily in organic solvent was solved. We offer a new experimental proof for PPL-catalyzed peptide synthesis and make a more general analysis for the effect of some factors in theory.
采用氯乙酰基保护天冬氨酸,然后进行氨解生成GD二肽,利用猪胰脂肪酶催化合成RGD三肽,着重解决了亲水氨基酸/肽片段底物的溶解性与合成产率低的问题,建立了一种新的有效合成RGD三肽的反应模型,并探索解决了极性较强的氨基酸的酶促肽合成的问题,对脂肪酶催化合成肽的影响因素从理论上作了较全面的分析,为肽片段的缩合反应提供了一种新思路。
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3A series of C_2-symmetric chiralβ-amino alcoholsⅢ-6 andⅢ-10were synthesized in several steps from natural amino acids,and applied in the asymmetric borane reduction of prochiral ketones.The catalytic activity ofⅢ-6 was better thanⅢ-10.
3以天然氨基酸为起始原料,经过简单的几步反应合成了开链冠醚类C_2-对称的手性β-氨基醇Ⅲ-6以及Ⅲ-10,将其应用于硼烷对前手性酮的不对称还原反应中,含有脯氨醇结构单元Ⅲ-6的催化效果要好于由其他氨基酸衍生的Ⅲ-10,THF为溶剂,回流,催化量为10 mol%时,最高得到85%的ee值。
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It was found during the experiment:the influence of gas flux under lower bound was distincter for benzene thanformaldehyde; there was no reaction heat produced during the process, so the temperature did not changed much; the relative humidity changed differently becauseof gas flux, absorbency and water vapor produced during experiment.
实验发现:低流量范围内流量对苯的降解效率影响比对甲醛的影响明显;光催化降解过程中,温度变化不大,反应生成热很少;由于气体流量、催化剂对气体的吸附以及反应生成的水蒸气的影响,光催化降解过程中,反应系统气相体系的相对湿度会有所变化。
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The 1%-Ni-doped TiO_2 calcined at 400℃has the best photocatalic ability.An indigo carmine solution of 10 mg/L was completely photodegraded in 50 minutes in the presence of as-obtained photocatalyst under visible light.A series of structure analysis,such as XPS,TEM,are employed to investigate the structure of the Ni/TiO_2 composite in details.The results indicate that at the lower temperature,instead of the simple interface compounding reported by some references,the Ni ions could be inserted into the crystal lattice of TiO_2,and form the innovative material.
通过XPS、TEM等多种表征手段对镍掺杂纳米二氧化钛的结构与光(来源:6414A41BC论文网www.abclunwen.com)催化性能进行了深入分析研究,发现在较低温度下煅烧可以获得镍离子晶格掺杂而不是表面复合的新型材料,通过镍离子缺陷能级的引入改变了二氧化钛的能级结构,提高了材料可见光下的光催化氧化的效率。
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Points of knowledge: To know the definition, performance, category and preparation of solid catalyst; characteristic of solid catalyst, basic course of gas-solid catalytic reaction, physical construction of catalyst; to understand the derivation of intrinsic kinetics of gas-solid catalytic reaction by using the Langmuir 's adsorption isothermal line.
知识要点:了解并掌握固体催化剂的定义、性能要求、种类和催化剂的制法;固体催化剂的特性,气-固相催化反应进行的基本过程,催化剂的物理结构;掌握朗哥缪尔吸附等温线推导气固相催化反应本征动力学的方法。
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The Research about the Synthesis of Phenylsulfonyl α,β-unsaturated Ketones and Their Applications in Asymmetric Diels-Alder Reaction Catalyzed by Lewis Acid and Chiral Titanium Reagents.
苯磺酰基取代的α,β-不饱和酮的合成及其在不对称催化Diels-Alder反应中的研究中文名称:苯磺酰基取代的α,β-不饱和酮的合成及其在不对称催化Diels-Alder反应中的研究
- 推荐网络例句
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Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).
呼气,收缩臀部肌肉;拱起身体,尽量抬起头来,右腿伸直朝向天花板(膝微屈,以避免肌肉紧张)。
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The cost of moving grain food products was unchanged from May, but year over year are up 8%.
粮食产品的运输费用与5月份相比没有变化,但却比去年同期高8%。
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However, to get a true quote, you will need to provide detailed personal and financial information.
然而,要让一个真正的引用,你需要提供详细的个人和财务信息。