γ-Al2O3对NiB合金的催化及表面性能的影响

集），Dalian（大连）：1994，p.262||8LiuWeicheng（刘伟成），YanJingqing（晏荆青），JiangBingnan（姜炳南）．CuihuaXuebao（催化学报），1990，||11（2）：929HuCW，WangWZXuGY，etal．J．Nat．GasChem，1994,（3）：194||     

Reaction Engineering Aspects of α-l,4-D-Glucan Phosphorylase Catalysis

Some important process properties of α-l,4-D-ghican phosphorylases isolated from the bacteriumCorynebacterium callunae and potato tubers (Solatium tuberosum) were compared. Apart from minor differences in their stability and specificity (represented by the maximum degree of maltodextrin conversion) and a 10-fold higher affinity of the plant phosphorylase for maltodextrin (K _M of 1.3 g/L at 300 mM of orthophosphate), the performances of both enzymes in a continuous ultrafiltration membrane reactor were almost identical. Product synthesis was carried out over a time course of 300–400 h in the presence or absence of auxiliary pullulanase (increasing the accessibility of the glucan substrate for phosphorolytic attack up to 15–20%). The effect of varied dilution rate and reaction temperature on the resulting productivities was quantitated, and a maximum operational temperature of 40°C was identified.     

中空纤维催化膜反应器中环戊二烯的选择加氢反应

将聚乙烯吡咯烷酮（ＰＶＰ）负载钯催化剂（ＰＶＰ－Ｐｄ）镶嵌到三种醋酸纤维（ＣＡ）中空膜（ＣＡ－Ｉ，ＣＡ－Ⅱ，ＣＡ－Ⅲ）内制各中空纤维催化膜，并进一步制成催化膜反应器，在４０℃和０．１ＭＰａ的反应条件下，在催化膜反应器中进行了环戊二烯的选择加氢反应，考察了具有不同氢气渗透率的醋酸纤维丝组成的三种膜反应器对反应的转化率及选择性的影响，并在此基础上考察了各种反应参数对反应的影响，ＣＡ中空纤维催化膜对环戊     

担载Ru_3（CO）_（12）－Fe_2（CO）_9混合簇的脱羰基作用和表面加氢反应

担载于ＺｒＯ２上的Ｒｕ３（ＣＯ）１２－Ｆｅ（ＣＯ）９混合簇的红外光谱表明，Ｒｕ３（ＣＯ）１２以Ｒｕ（ＣＯ）２Ｏ２表面络合物存在．混合族在真空中随温度升高而发生脱羰基作用，５００℃左右羰基完全脱掉；以Ａｌ２Ｏ３为载体者其羰基不易脱除，升高温度出现多种羰基带．混合簇中的Ｆｅ２－（ＣＯ）９极易脱羰基．担载混合簇在Ａｒ气中进行ＴＰＤＥ时，低温时以脱羰基为主，高于１５０℃时发生表面歧化反应而生成ＣＯ２；在Ｈ２气中，低温时仍以脱羰基为主，高于１５０℃时发生表面加氢反应而生成ＣＨ４．混合簇的脱羰基和表面反应能力与Ｒｕ／Ｆｅ比及载体有关．担载混合簇在ＣＯ加氢反应中以Ｒｕ（ＣＯ）２Ｏ２和分散Ｆｅ存在，还出现－ＣＨｘ多种表面物种．     

Ni-B非晶态合金催化苯丙酮酸加氢合成苯丙氨酸

通过化学还原法制备了纳米非晶态Ni-B合金催化剂,考察了其对苯丙酮酸胺化加氢合成苯丙氨酸的催化性能.结果表明,相对于传统雷尼镍和漆原镍催化剂,非晶态合金催化剂表现出更为优异的活性和选择性,并且当非晶态Ni-B合金负载在SiO2载体上时,其活性和选择性均得到较大提高(高达97.67%).非晶态合金催化剂对苯丙氨酸合成反应表现出较好活性和选择性的原因主要是硼提供部分电子给镍的效应以及非晶态合金颗粒的纳米尺寸效应.     

潜手性Schiff碱不对称催化还原反应研究进展

对近年来潜手性Schiff碱的不对称催化氢化的发展状况按照均相、非均相及氢转移催化氢化三种类型进行了较为详尽的综述.     

Preparation of Layer Structure-Controlled Ru-Sn-Al2O3 Catalysts and Their Reactivity

In order to achieve functional group selective hydrogenation, the layer structure of Ru-Sn-Al2O3 catalysts was controlled by using sol-gel, powder impregnation and combined sol-gel impregnation methods. The properties of the catalysts and effectiveness in hydrogenation of dimethyl terephthalate were examined. The surface Sn contents of the catalysts characterized by X-ray photoelectron spectroscopy depended on the preparation method, in spite of almost the same bulk Ru and Sn compositions measured by X-ray fluorescence analyses. TPR and CO adsorption of the catalysts also depended on the preparation method. With regard to the conversion rate of dimethyl terephthalate and the rate of product conversion from methyl 4-hydroxy methylbenzoate to p-xylene via methyl p-toluate, Ru impregnation catalysts had higher rates than the other catalysts.     

高分子稳定的钌纳米金属簇选择性催化氢化巴豆醛

以聚乙烯吡咯烷酮稳定的钌纳米金属簇(PVP-Ru)为催化剂,进行了巴豆醛的选择性催化氢化。结果表明,反应体系中水和氢氧化钠的引入,可提高催化活性,但降低了选择性。某些金属阳离子对PVP-Ru的修饰作用使选择性有所提高,但降低了催化活性。尤其是经Co2 修饰后,巴豆醇的最高产率为5.5%,而催化活性由150.4 mol巴豆醛/mol Ru.h降至96.7 mol巴豆醛/mol Ru.h。     

Existence of finitely optimal solutions for infinite-horizon optimal control problems

In this paper, we investigate the existence of finitely optimal solutions for the Lagrange problem of optimal control defined on [0, ) under weaker convexity and seminormality hypotheses than those of previous authors. The notion of finite optimality has been introduced into the literature as the weakest of a hierarchy of types of optimality that have been defined to permit the study of Lagrange problems, arising in mathematical economics, whose cost functions either diverge or are not bounded below. Our method of proof requires us to analyze the continuous dependence of finite-interval Lagrange problems with respect to a prescribed terminal condition. Once this is done, we show that a finitely optimal solution can be obtained as the limit of a sequence of solutions to a sequence of corresponding finite-horizon optimal control problems. Our results utilize the convexity and seminormality hypotheses which are now classical in the existence theory of optimal control.This research forms part of the author's doctoral dissertation written at the University of Delaware, Newark, Delaware under the supervision of Professor Thomas S. Angell.