Toward rational design of hierarchical beta zeolites: An overview and beyond

The ever-growing need to increase the efficiency of crude oil refining raises the prospects for utilizing advanced catalytic materials to supply increasing global demands for fine chemicals and petrochemicals. Zeolites have been used as indispensable catalysts in many commercial refining processes. Among them, zeolite beta is one of the most widely produced zeolite materials with industrial significance due to its large micropores and three-dimensional pore structures. This article discusses recent progress on hierarchical beta zeolites from various synthetic strategies. Using zeolite beta as a representative case, we provide an overview on key aspects that are applicable to different zeolites via a variety of topics, such as selection of different template materials, tailoring of mesopore sizes by base leaching, organotemplate-free synthesis of hierarchical zeolites, and selective desilication. This article concludes with a perspective on the design of scalable hierarchical zeolites that are more relevant as industrial catalysts in commercial processes.     

乙烯选择性四聚制1-辛烯催化剂及工艺技术研究进展

综述了近年来乙烯选择性四聚制1-辛烯技术的发展现状。介绍了乙烯选择性四聚制1-辛烯催化剂研究的最新进展及发展趋势;重点阐述了影响乙烯选择性四聚制1-辛烯催化体系中的两个重要组分,即助催化剂和配体;从技术和经济方面对比了现有技术制1-辛烯的可行性。     

Chromium catalysts supported on mesoporous silica for ethylene tetramerization: Effect of the porous structure of the supports

Supported chromium catalysts were prepared by loading Cr(acac)₃ and N-isopropyl bis(diphenylphosphino)amine (PNP) onto methylaluminoxane-modified MCM-41 and SBA-15. The structure of supported catalysts was characterized and the influence of the pore structure of supports on the reactivity for ethylene tetramerization was investigated. The results revealed that the chromium was immobilized on the mesoporous silica in different supported patterns, which was affected by the pore size of the supports and affected catalyst performance. The highest selectivity toward 1-octene was provided by the SBA-15-supported Cr(acac)₃/PNP catalyst, and this value was higher than that of the homogeneous analogs.     

乙烯四聚制1-辛烯的研究

研究了乙烯选择性四聚制1-辛烯的催化剂体系,利用氯化二苯基膦与胺反应生成二苯基膦胺配体,它与乙酰丙酮铬在助催化剂的存在下显示出较高的催化乙烯四聚的活性和较高的1-辛烯选择性;考察了不同溶剂、温度、压力、n(Al)/n(Cr)及第四组分对催化剂体系的影响,确定了适宜的条件,当n(Cr)/n(PNP)/n(Al)为1∶2∶300,反应温度为30℃,压力为3 MPa时,反应时间为30 min,进行乙烯四聚实验,催化剂活性达58.10 kg/(g·h),1-辛烯的选择性接近70%。     

乙烯四聚催化体系双膦胺配体的结构与性能

简述了乙烯四聚反应制备1-辛烯催化体系的最新研究进展.指出乙烯四聚制1-辛烯催化体系中配体的结构和电子性是影响催化体系的活性和目的产物1-辛烯的选择性的主要因素.PNP配体中N取代基和P取代基的空间位阻和给电子效应都会对催化体系的活性和1-辛烯选择性产生影响.分析了由于取代基空间体积的增大和电负性的增强均使乙烯的进一步...     

Toward rational design of ceramic coatings generated on valve metals by plasma electrolytic oxidation: The role of cathodic polarisation

Plasma electrolytic oxidation (PEO) has attracted significant attention as a promising eco-friendly technology for the deposition of ceramic-like oxide coatings with superior wear- and corrosion resistance as well as biomedical, catalytic, magnetic, dielectric and optical properties. However, the industrial implementation of PEO has been hindered by a poor understanding of the mechanisms underlying plasma-assisted electrochemical coating formation. This study compares the characteristics of PEO processes on different valve metals in a dilute aqueous solution of NaOH and Na₂SiO₃ under pulsed unipolar and bipolar polarisation conditions. The focus is given to the influence of the nature of the valve metal on the transition to the soft sparking regime characterised by reduced energy consumption whilst yielding sintered coating materials enriched with crystalline phases. In-situ dynamic voltammetry analysis was employed to study the effects of the net current ratio and local negative charge injection using diagnostic pulses embedded in the polarisation signal. It has been demonstrated that soft sparking is a characteristic feature of valve metals such as Mg, Al, Zr and Ta that form insulating surface oxides with negligible electronic conductivity, whereas Ti and Nb form semiconducting oxides, which do not exhibit a characteristic voltage drop, although some features of spark softening were detected. This generalisation paves a way for implementation of a model known as ‘digital twin’ to the rational design of the PEO processes for deposition of the functional ceramics.     

高效分离乙烷/乙烯的烷烃选择性吸附剂研究进展

乙烯是石油化学工业的基础原材料,聚合级乙烯工业纯化的关键挑战是去除其中的乙烷杂质,这一步骤难度大、能耗高。近年来,以乙烷选择性吸附剂为核心的吸附分离纯化技术快速发展,并得到学术界和工业界的关注。该技术可在温和工况下高选择性分离出乙烯中的乙烷杂质,显现出巨大潜力。本文总结了近年来乙烷选择性吸附剂（特别是乙烷选择性MOFs）的研究进展,并归纳阐释其选择性吸附机理。同时,在前人研究成果的基础上,总结可行的乙烷选择性吸附剂的设计策略,指出当前开发高效乙烷选择性吸附剂面临的挑战和未来的研究方向。     

高效分离乙烷/乙烯的烷烃选择性吸附剂研究进展

乙烯是石油化学工业的基础原材料,聚合级乙烯工业纯化的关键挑战是去除其中的乙烷杂质,这一步骤难度大、能耗高。近年来,以乙烷选择性吸附剂为核心的吸附分离纯化技术快速发展,并得到学术界和工业界的关注。该技术可在温和工况下高选择性分离出乙烯中的乙烷杂质,显现出巨大潜力。本文总结了近年来乙烷选择性吸附剂（特别是乙烷选择性MOFs）的研究进展,并归纳阐释其选择性吸附机理。同时,在前人研究成果的基础上,总结可行的乙烷选择性吸附剂的设计策略,指出当前开发高效乙烷选择性吸附剂面临的挑战和未来的研究方向。     

Reviewing ligand-based rational drug design: the search for an ATP synthase inhibitor

Following major advances in the field of medicinal chemistry, novel drugs can now be designed systematically, instead of relying on old trial and error approaches. Current drug design strategies can be classified as being either ligand- or structure-based depending on the design process. In this paper, by describing the search for an ATP synthase inhibitor, we review two frequently used approaches in ligand-based drug design: The pharmacophore model and the quantitative structure-activity relationship (QSAR) method. Moreover, since ATP synthase ligands are potentially useful drugs in cancer therapy, pharmacophore models were constructed to pave the way for novel inhibitor designs.     

Toward a CO2-free ethylene oxide process: Homogeneous ethylene oxide in gas-expanded liquids

Among industrial chemical processes, ethylene oxide manufacture emits the largest amount of CO₂ (∼2-3 million tons/yr), as byproduct from the burning of both the ethylene (feed) and ethylene oxide. Further, the conventional silver-based catalytic process presents safety challenges due to the formation of explosive ethylene oxide/O₂ mixtures in the gas phase. By judicious choice of the catalyst (methyltrioxorhenium), oxidant (H₂O₂) and reaction medium (methanol/water), a homogeneous liquid phase catalytic system has been demonstrated that eliminates CO₂ formation while producing ethylene oxide at >90% selectivity at near-ambient temperatures. Given its high volatility, the ethylene oxide is easily recovered from the reaction phase by distillation. The vicinity of the gaseous ethylene feed to its critical temperature (9 °C) is exploited to significantly increase its solubility in the liquid reaction phase by facile compression beyond the critical pressure of ethylene (∼50 bar). Since H₂O₂ is stable at typical reaction temperatures (40 °C or less), potentially explosive ethylene oxide/O₂ mixtures are avoided in the gas phase. In addition to the potential of arresting the carbon footprint of a large-scale industrial process, the demonstrated process concept shows how gas-expanded liquids can be generally exploited in homogeneous catalysis to enhance productivity.     

用于乙丙橡胶生产的钒醇配体催化剂的制备研究

从乙丙橡胶催化剂需要出发,以含钒浓度高的盐酸溶液为初始水相,高浓度脂肪醇溶液为初始有机相,控制适当游离酸度,采用萃取的方法制备出钒醇配合物的己烷溶液用于乙丙共聚的催化剂,经实验研究其存放稳定性及催化性能均优于工业VOC13催化剂,且制备条件温和、成本低。     

Cybernetic modeling of metabolism: towards a framework for rational design of recombinant organisms

Most cybernetic modeling efforts to date have taken a minimalist viewpoint of metabolism, relying heavily upon process lumping and pathway abstraction to simplify the underlying reaction network. However, such models are unsuitable for metabolic engineering applications because they do not incorporate the level of biological detail that is needed to predict the effects of genetic perturbation. In this paper, we inquire into the formulation and analysis of structured cybernetic models as tools for metabolic engineering. We present fresh theoretical developments leading to a more systematic treatment of global cybernetic variables based on conservation of metabolic resources. Finally, we illustrate these concepts with a cybernetic model-based analysis of anaerobic Escherichia coli metabolism. The model is able to accurately describe the growth of wild-type and acetate knockout strains when fitted to experimental data. Although it adequately predicts the end-of-batch concentrations for a strain with intermediate pta-ackA activity, it overestimates the measured growth and glucose uptake rates.     

集成CO2高效利用的煤制乙二醇过程设计与系统分析

为减少传统煤制乙二醇过程资源利用效率低和CO₂排放量高等问题，提出了一种集成CO₂高效利用的煤制乙二醇过程，并对其进行了全流程建模及系统分析。与传统过程不同，新过程利用焦炉气来提高其资源利用率和能量效率，集成甲烷干重整与湿重整技术降低CO₂排放。在全流程建模的基础之上，对新工艺的关键操作参数进行了分析与优化。结果表明，焦炉气的最佳进料比和甲烷蒸汽重整反应的分配比为0.68和0.74。与传统过程相比，新工艺的CO₂排放降低了94.05％，同时?效率提高了15.17％。     

乙烯装置控制室的安全设计防护

乙烯装置中的控制室，是整个生产过程的重要组成部分。在高温、高压、易燃、易爆的乙烯生产装置中，既要保证控制室内的仪表设备安全正常运转，又要保证人员的安全，是整个控制室设计要考虑的关键问题。     

裂解炉对流段的模块化设计

通过对某乙烯装置12万t/a裂解炉对流段的模块化设计,从设计角度对模块化程度选择、模块规格的确定和模块化图纸的风格和特点等方面进行了简要的阐述.