高速筛选技术在组合催化中的应用

介绍了近年用于组合催化技术研究中的几种使用高速筛选技术的反应器,包括红外温度记录型反应器、荧光检测型反应器、利用共振强化多光子离子化技术的反应器等等。     

Promising zeolite-type hydrocarbon trap catalyst by a knowledge-based combinatorial approach

Libraries consisting of more than 100 zeolite samples were prepared and examined for developing a promising HC trap catalyst. Parallel adsorptions of toluene onto the catalyst samples were conducted over a 10 × 10 array reactor under dry and wet conditions with or without a heating process three knowledge-based conditions for developing an automotive catalyst during the cold-start period. FAU and BEA type zeolites revealed a high performance of toluene adsorption under the dry condition. However, FAU type zeolite significantly decreased the amount of toluene adsorbed in the presence of water in the feed gas stream, mainly due to the hydrophobicity of the catalyst surface. Over Beta type zeolites, the toluene adsorbed was found to be considerably preserved, even after forced desorption temperature-ramping to the warm-up condition of an automotive engine. Li, K, or Ag ion-exchanged Beta zeolites seem to be particularly promising as an HC trap catalyst.     

Chemically sensitive parallel analysis of combinatorial catalyst libraries

This study demonstrates how Fourier transform infrared imaging (FTIR) can be employed as a powerful spectroscopic tool for the parallel investigation of multiple member heterogeneous catalyst systems. FTIR imaging combines the chemical specificity and high sensitivity of infrared spectroscopy with the ability to rapidly analyze multiple samples simultaneously. A new implementation, using a rapid-scan FTIR spectrometer instead of a step-scan FTIR spectrometer, allows much improved data collection times without sacrificing data quality. Using CO adsorption and CO oxidation as model systems, it was established that FTIR imaging is very well suited to high-throughput parallel analysis of adsorbates and reaction products from supported catalyst libraries.     

微波增强TiO2光催化降解染料和水杨酸

引言 作为一种先进的氧化技术,多相光催化在有机污染物的降解中发挥着重要的作用,已成为环境科学领域最为活跃的研究方向之一.利用多相光催化氧化反应可以消除和降解水中多种有机污染物,如染料、杀虫剂、表面活性剂等[1-3].然而,在光催化反应中,大部分光生空穴和电子在被OH·或O2捕获之前已经重组,这样导致量子效率较低(小于5%),而低量子效率导致了光催化降解率较低,以致应用光催化时需要大的反应器和较长的反应时间.     

磁性碳纳米管基催化剂TiO2/CNTs光降解氨比西林抗生素水溶液的研究

以磁性多壁碳纳米管(MWCNTs)为载体,钛酸四丁酯为钛源,采用表面溶胶包覆-醇热联用法制备TiO2/CNTs复合管光催化剂。以氨比西林溶液的降解为目标反应,考察了催化剂在紫外灯下的催化活性。结果表明,二氧化钛在MWCNTs表面分布均匀,提高了对光的吸收和利用,因此TiO2/MWCNTs复合光催化剂表现出较高的光催化活性,催化剂的活性随着pH值的增大而增大,并且磁性催化剂易从降解后的溶液中分离。     

Clean borrowing hydrogen methodology using hydrotalcite supported copper catalyst

The catalytic activity of Mg–Al hydrotalcite supported copper catalyst was investigated for clean CC and CN bond forming reactions using alcohols as alkylating agent via borrowing hydrogen methodology. The catalyst showed excellent conversion of ketone and amine substrates (71–99%) to alkylated products with high selectivity in alkylation reactions.     

Miniaturization of screening devices for the combinatorial development of heterogeneous catalysts

The present work is focused on the determination of the advantages, bottlenecks and challenges of miniaturized screening systems which are essential to the success of combinatorial high-throughput methodologies in heterogeneous catalysis. Two different reactor configurations with different degrees of miniaturization were developed for the parallel and fast screening of heterogeneously catalyzed gas phase reactions: a monolithic reactor system acting as a multichannel reactor and a microreaction system based on microfabrication techniques. In both cases, a scanning mass spectrometry technique was successfully applied for quantitative product analysis within 60 s per catalyst. Due to its flexibility and high spatial resolution, this three dimensional scanning MS can be used with different and highly parallel reactor arrays. Many experiments were carried out to study the efficiency and reliability of the different screening systems, with the oxidation of methane, the oxidation of CO, and the oxidative dehydrogenation of i-butane as model reactions. Moreover, chip modules in silicon–glass technology having a number of parallel microchannels were developed, each of them containing a different catalyst. Using this approach, “catalysis-on-a-chip” proved in methane oxidation was possible. Finally, a multibatch reactor consisting of a number of parallel mini autoclaves was developed and tested in the liquid-phase hydrogenation of citral in order to overcome the lack of parallel and fast screening procedures for heterogeneously catalyzed gas–liquid reactions widely spread in the chemical industry.     

纳米碳化硅对染料罗丹明B的光降解性能研究

以石墨作为碳源,正硅酸乙酯作为硅源,硝酸钴作为催化剂,采用溶胶-凝胶法和碳热还原法制备纳米碳化硅,并对其光催化性能进行研究。讨论了不同Si C用量、不同p H值、不同光源下纳米碳化硅对罗丹明B的光催化降解效果。结果表明：在250W紫外灯照射条件下,当p H=1,催化剂量为100mg时,罗丹明B的光降解效果最好,最高降解率可达58.52%。     

Digital screening methodology for the directed evolution of transglycosidases

Engineering of glycosidases with efficient transglycosidasesactivity is an alternative to glycosyltransferases or glycosynthasesfor the synthesis of oligosaccharides and glycoconjugates. However,the engineering of transglycosidases by directed evolution methodologiesis hampered by the lack of efficient screening systems for sugar-transferactivity. We report here the development of digital imaging-basedhigh-throughput screening methodology for the directed evolutionof glycosidases into transgalactosidases. Using this methodology,we detected transglycosidase mutants in intact Escherichia colicells by digital imaging monitoring of the activation of non-or low-hydrolytic mutants by an acceptor substrate. We screenedseveral libraries of mutants of β-glycosidase from Thermusthermophilus using this methodology and found variants withup to a 70-fold overall increase in the transglycosidase/hydrolysisactivity ratio. Using natural disaccharide acceptors, thesetransglycosidase mutants were able to synthesise trisaccharides,as a mixture of two regioisomers, with up to 76% yield.     

云铜公司催化剂筛分装置简介

催化剂筛分是硫酸厂大修中一项比较难的工作 ,催化剂筛分装置运行的好坏直接影响到整个检修任务能否按时完成。多年以来 ,催化剂筛分一直是困扰我公司的一大难题。硫酸一系列催化剂筛分装置经过多次改进与完善 ,仍然存在抽吸催化剂速度慢的问题。我公司新建硫酸四系列时 ,自行设计、新建了 1套 7ｍ3/ｈ催化剂筛分装置 ,解决了抽吸催化剂困难的问题 ,使用效果良好。1　催化剂筛分工艺流程和主要设备硫酸四系列采用 5段转化 ,催化剂装填量为2 0 8 1 1ｍ3。新建催化剂筛分装置 ,需兼顾正在改造的硫酸三系列。根据这些情况 ,首先确定筛分装置的…     

Photodegradation of ethylene/propylene/polar monomers,co‐, and terpolymers. II. Prepared by Ni catalyst systems

The copolymers of ethylene/propylene as well as their terpolymers with polar monomers were prepared by Ni‐catalyst systems and their photodegradation behavior was studied by Fourier transform infrared spectroscopy. The polar monomers used to synthesize co‐ and terpolymers of ethylene/propylene/polar monomer were 5‐hexen‐1‐ol, 10‐undecen‐1‐ol, acrylamide, methylmethacrylate, acrylonitrile, and methylvinyl ketone. The morphological changes of the irradiated samples were determined by scanning electron microscopy. The photodegradation kinetics has also been studied. The surface damage caused by polychromatic irradiation (λ ≥ 290 nm) at 55 °C in atmospheric air is presented in different micrographs. The rate of photo‐oxidative degradation is very fast in terpolymers containing polar monomers as compared with copolymers and homopolymers. The morphological study of the photodegraded samples showed a very good correlation with the photodegraded results. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 104: 1783–1791, 2007     

纳米二氧化钛陶瓷球光催化降解菲研究

采用纳米TiO2陶瓷球为光催化剂处理含菲水溶液,考察了温度、不同光源、pH、Ca2+、Fe3+等因素对降解的影响。结果表明,在高压汞灯下该陶瓷球具有良好的光催化效果,温度、pH、Ca2+均对其光催化降解菲没有明显影响;表面覆盖率和光降解呈负一级反应动力学关系;在0.3~1.5 mmol/L浓度下Fe3+能促进其光催化降解速率;过硫酸钾能提高其降解速率;二氧化钛陶瓷球经过8次重复回收利用后,光催化降解率由最初的96.09%逐渐下降至73.97%。通过GC-MS检测到一些菲降解中间产物,推测了菲光降解的途径。     

Mg掺杂TiO_2光催化降解孔雀绿染料的研究

采用溶胶-凝胶法制备的Mg掺杂TiO2光催化剂降解孔雀石绿(MG)染料废水,考察了MG初始浓度、催化剂加入量等因素对其降解的影响。结果表明,Mg的掺杂显著提高了TiO2光催化降解孔雀石绿的活性,当催化剂用量为1.0 g/L,经120 min紫外光照射后,可使30 mg/L孔雀石绿溶液降解率达到84%,同时讨论了光催化机制。     

In situ generation and screening of a dynamic combinatorial carbohydrate library against concanavalin A

Dynamic combinatorial chemistry (DCC) is a recently introduced approach that is based on the generation of combinatorial libraries by reversible interconversion of the library constituents. In this study, the implementation of such libraries on carbohydrate-lectin interactions was examined. The dynamic carbohydrate libraries were generated from a small set (four or six compounds) of initial carbohydrate dimers through mild disulfide interchange, and selection was performed under two conditions defining either adaptive or pre-equilibrated libraries. Upon initiation, libraries were formed that contained comparable amounts of 10 or 21 individual dimeric species, dynamically interchanging during the scrambling process. They were probed with respect to binding to the plant lectin concanavalin A, either present during library generation or added after equilibration. The libraries could be generated easily both in the presence and absence of the receptor, and a bis-mannose structure was preferentially bound and selected from the mixture. Scrambling of the library in the presence of the receptor resulted in slightly higher yields than when the receptor was added after scrambling, indicating that the receptor to some extent acts as a thermodynamic trap during library generation. The present results illustrate the extention of the DCC approach to carbohydrate recognition groups, the generation of isoenergetic dynamic libraries, and the implementation of either adaptive or pre-equilibrated procedures.     

Selective oxidation of alcohols by combinatorial catalysis

High-throughput synthesis and screening of polyoxometalate (POM) and supported-metal libraries have been developed for the selective aerobic oxidation of alcohols to the corresponding aldehydes/ketones in the liquid phase. Libraries consisting of 96 catalysts were prepared in multi-well reactors and screened for catalytic activity using TLC, GC and NMR detection methods. Promising hits identified in the high-throughput primary screens were successfully scaled up and optimized in conventional laboratory test units. Isolated yields confirm high selectivities of more than 90% with quantitative conversions. Substrates tested include primary and secondary alcohols. Specific results will be presented for hydroxymethyl-substituted heterocycles and bicyclo-octanols.     

Catalytic conversion of urea to biuret: A catalyst screening study

Biuret was synthesized from urea in a batch reactor using various homogeneous and heterogeneous catalysts, with the aim of searching for efficient catalyst in converting non-catalytic reaction to catalytic reaction. For this purpose, zeolite, heteropolyacid, organic acid and base, multicomponent bismuth molybdate, and multicomponent bismuth molybdate-alumina mixed catalysts were tested. It was revealed that the performance of catalytic reaction was better than that of non-catalytic reaction in the synthesis of biuret from urea. Among the homogeneous acid and base catalysts tested, thionyl chloride (SOCl₂) showed the best catalytic performance. Among the heterogeneous catalysts tested, on the other hand, a mixed catalyst comprising multicomponent bismuth molybdate (Co₈Fe₃Bi₁Mo₁₂O₅₀) and alumina showed the best catalytic performance.     

烟嘧磺隆废水的光降解研究

本文主要研究了烟嘧磺隆废水的光降解特性,考察了照射光源、烟嘧磺隆初始浓度、溶液初始p H值等因素对烟嘧磺隆光降解的影响。结果表明,汞灯照射的光解效果优于氙灯照射;汞灯照射下,p H值为7时光解效果最好,并且随着烟嘧磺隆初始浓度的增加,光解的半衰期增大。