PROMOTION EFFECT OF Mo IN AMORPHOUS Ni-P CATALYSTS FOR THE LIQUID-PHASE CATALYTIC HYDROGENATION OF NITROBENZENE TO ANILINE

Amorphous Ni-P catalysts were prepared by a chemical reduction method, and the promotional effects of Mo on the hydrogenation of nitrobenzene to aniline on Ni-P catalyst were investigated. However, the two crystallization temperatures of the 1% Ni-Mo-P catalyst were 644 K and 723 K, which were 15 K and 43 K higher, respectively, than those of the Ni-P catalyst itself; these results indicate that the presence of Mo increased the thermal stability of the Ni-P catalysts. SEM results showed that the particle size of the active component of Ni-P in the 1.0% Ni-Mo-P catalyst was smaller than that in the amorphous Ni-P catalyst. The N₂ adsorption isotherms for the amorphous Ni-Mo-P catalysts were the III-type, and the N₂ isothermal adsorption-desorption curves exhibited H₃-type hysteresis loops. H₂-TPR results showed that the addition of Mo had no effect on the reduction of NiO in the catalyst but negatively affected the reduction of Ni-P-O. H₂-TPD results showed that the hydrogen adsorption capacity of the amorphous Ni-P catalysts can be enhanced through the addition of Mo, and the optimal amount of Mo was determined to be 1.0%. The XPS results indicated the presence of a small amount of free metallic Mo in the amorphous Ni-Mo-P catalysts in addition to the Mo in MoO₃. The use of 1% amorphous Ni-Mo-P catalyst at 383 K and under 1.0 MPa of hydrogen for 3.0 h resulted in a nitrobenzene conversion rate and aniline selectivity of 64.5% and 98.8%, respectively.     

延长裂解汽油加氢催化剂使用寿命的探讨

根据LY-8602C型催化剂在中国石化齐鲁石化股份有限公司烯烃厂裂解汽油加氢装置的使用经验，对影响加氢催化剂的使用寿命的因素（如原料性质、催化剂再生、催化剂装填、进料温度、氢油比、循环操作等）进行了系统的分析，并提出了改进措施。     

在加压积分反应器上气相苯加氢Pt／Al2／O3催化剂的活性评价

采用加压积分反应器装置,对研制的 Pt/Al_2O_3催化剂应用于气相苯加氢反应进行了研究,得到了该催化剂使用的最适工艺条件为:t=220～270℃、P=0.6～1.0MPa、液相苯空速=0.8～3.2h~(-1)、氢苯比=4～5(摩尔比),在上述条件下操作,苯的转化率达100%,环己烷的收率也在99.6%以上。在此基础上,进一步考察了催化剂的耐热性、抗硫中毒性及经反复开停车的试验,证实 Pt/Al_2O_3催化剂在这些方面均比 Pd/C 及目前工业上应用的 Ni/Al_2O_3催化剂为优,是具有工业应用前景的一种负载型贵金属催化剂。     

气相苯加氢制环己烷pt/Al_2O_3催化剂的研究

采用常压、固定床,连续流动的反应装置,研究了气相苯加氢的 Pt/Al_2O_3催化剂的制备方法、制备条件、载体上铂的负载量及不同方法制得的载体对催化活性的形响。在评价催化活性时,采用的工艺条件为:温度240℃、液相苯空速0.8时~(-1)、氢:苯=4(摩尔比),并用转化率来表征催化剂的活性。结果发现,用离子交换法制备的负载型 Pt/Al_2O_3催化剂,对苯的气相加氢显出很高的活性,当铂的负载量为0.55%时,苯的转化率已达100%,环己烷的产率也达99%以上,将活性与用 H_2—O_2滴定和 Auger 电子能谱测得的金属分散度数据进行关联,得到了一致的结果。金属分散度高,催化剂的活性也佳,说明金属的分散度是直接影响到催化剂的活性,而寻找制备金属高分散度的催化剂制备方法,是研究工作成功的关键。     

HYDROGEN DIFFUSIVITY ENHANCEMENT IN ALUMINA PELLETS DUE TO IMPREGNATED PALLADIUM

Single-pellet moment technique was used for the evaluation of effective diffusivities and adsorption equilibrium constants of hydrogen, carbon dioxide, and helium in pure alumina and palladium-impregnated alumina pellets. It was found that hydrogen was strongly adsorbed on palladium of Pd-alumina pellets, and significant enhancement of hydrogen diffusivity was observed due to impregnated palladium at 40°C. On the other hand, for carbon dioxide and helium, effective diffusivities obtained in Pd-alumina pellets were smaller than the corresponding values in pure alumina due to higher tortuosity factor values of Pd-alumina pellets.     

INTRAPARTICLE CONVECTION,DIFFUSION AND ZERO ORDER REACTION IN POROUS CATALYSTS

An assessment is made of the influence of convective effects in the behaviour of calalyst pellets with large pores

Concentration profiles and effectiveness factors are calculated for zero order reactions in isothermal regimes using a model which involves convective transport as well as diffusion and reaction processes in the pellet

Errors made in current reactor design are discussed. A predictive method for calculating the intraparticle fluid velocity in industrial cases is reported. Finally, the analysis is applied to the design of biological reactors.     

Raney－Ni浸取方法对木糖加氢活性的影响

在木糖加氢反应中，考察了浸取（Ｌｅａｃｈｉｎｇ）方法对Ｒａｎｅｙ－Ｎｉ催化剂活性的影响。合金原料是１６０～２００目及＜３２０目的Ｎｉ－Ａｌ－Ｔｉ。实验表明，温度（５０～９３℃）及ＮａＯＨ浓度（２～６ｍｏｌ／Ｌ）越高，催化剂活性越好。但是，若先在低温和稀碱下浸取，再继以高温和浓碱的后处理，则比单一条件浸取时活性好。浸取起始１０～２０ｍｉｎ的反应剧烈程度，对合金破碎情况和催化剂活性均有显著影响；而后处理使活性提高的主要原因是对催化剂微孔的扩孔作用。     

INTRAPARTICLE CONVECTION, DIFFUSION AND ZERO ORDER REACTION IN POROUS CATALYSTS

An assessment is made of the influence of convective effects in the behaviour of calalyst pellets with large pores

Concentration profiles and effectiveness factors are calculated for zero order reactions in isothermal regimes using a model which involves convective transport as well as diffusion and reaction processes in the pellet

Errors made in current reactor design are discussed. A predictive method for calculating the intraparticle fluid velocity in industrial cases is reported. Finally, the analysis is applied to the design of biological reactors.     

SBS及相关聚合物的均相催化加氢进展

对SBS及相关聚合物加氢的各种均相催化体系作了全面的介绍与评述。重点介绍了近年来发展的茂金属催化剂和贵金属催化剂，同时介绍了水／有机两相催化和离子液体两相催化体系用于聚合物加氢的最新动态，指出寻找催化活性高，催化剂易于分离和循环使用的新催化体系是实现聚合物均相催化加氢工业应用突破的关键。     

CATALYSTS DESIGNED FOR USE IN THE WENTWORTH PROCESS FOR METHANOL AND HIGHER ALCOHOL SYNTHESIS

I would like to begin this paper with a personal accolade for Donald Othmer. It has been my pleasure to work with him for the last twelve to fifteen years and with T.O. Wentworth who, together with the author, are co-inventors of the process as described in U.S. Patent 4,235,799. Don has been a very devoted advocate to the research resulting in the generation of the patent. In meetings with him and Ted Wentworth, Ted and I were always amazed at the speed with which Don comprehended any new concept and immediately was able to respond with his own extension of the ideas. In addition to his mental skills, which are legendary, he also has ways with people. Always having a ready smile and quick wit and ready humor, his generosity is exceptional and is well known. As stated above our association was primarily in the derivation, researching and patenting of the unique methanol synthesis process covered by the above numbered patent which was assigned to Wentworth Bros. Inc. Wentworth Bros. Inc., in addition to other areas of expertise, are designers of methanol synthesis processes and have been in this business for at least fifty years.     

GRAIN GROWTH AND DENSIFICATION IN PALLADIUM OXIDE PARTICLES DURING SPRAY PYROLYSIS

A model for aerosol-phase densification of particles during their synthesis by spray pyrolysis is presented. The model was used to describe the evolution of the specific surface area of PdO powders synthesized at temperatures between 400 to 800 °C (residence times 27.9 to 22.7 s). Surface areas and grain sizes ranged between 56 m²/g and 4 nm at 400 °C to 3.2 m²/g and 40 nm at 800 °C The characteristic coalescence lime was determined as: τ= 1.7 x 10¹³T d³ exp(1.3 x 10⁵/RT) [for lattice diffusion] and t = 2.7 x 10¹⁹Td⁴exp (1.6 x 10⁵/RT) [for grain boundary diffusion] (τ is in seconds, Tin degrees Kelvin, R is 8.314J/(mol.K)and d is in meters), but the data and model did not allow identification of the specific mechanism. The model provides a general approach for correlating changes in particle surface area with reactor operating conditions that is applicable to a wide variety of materials.     

Hydrogenation of Cinnamaldehyde over Pt‐Modified Molecular Sieve Catalysts

The catalytic properties of various Pt‐modified molecular sieves were tested in liquid‐phase hydrogenation of cinnamaldehyde and compared to Pt/MgO and commercial Pt/C catalysts. The type of support considerably influenced the catalytic properties. The superior selectivity performance of microporous catalysts was confirmed; the highest selectivity to allyl alcohol of about 40 % was obtained over the beta support whereas the mesoporous MCM‐41‐supported catalyst was unselective. The highest activity was obtained over the Pt/mordenite catalyst. In order to clarify the performance of catalysts, several characterization methods (XRD, XRF, FTIR, surface measurements) were employed.     

Selective Hydrogenation of Citral in an Organic Solvent,in a Ionic Liquid,and in Substance

It is investigated whether the catalyst system Ag‐In/SiO₂ can be applied in the selective hydrogenation of citral, with the aim of synthesizing the acyclic, allylic terpene alcohols geraniol/nerol with high selectivity and space‐time yield. In addition, as liquid‐phase hydrogenations are often also influenced by the choice of solvent, it is of interest to know how the solvent, in particular in terms of its polarity and hydrogen solubility, affects the activity and the selectivity of catalysts during hydrogenation of the α,β‐unsaturated aldehyde citral.     

负载型钯酞菁催化剂上CCl2F2的选择性加氢脱氯反应

负载型钯酞菁能有效催化CCl₂F₂的选择性加氢脱氯反应,在氟化物为载体的钯酞菁催化剂上,CCl₂F₂转化成CH₂F₂的选择性可达75％以上.对比研究表明,负载型钯酞菁催化剂上CCl₂F₂选择性加氢脱氯的稳态催化活性要高于普通的负载型金属钯催化剂.在钯活性中心引入环状酞菁配体能有效提高催化剂在高腐蚀性反应条件下的稳定性.红外光谱、X射线衍射和紫外-可见光谱表征揭示了负载型钯酞菁催化剂具有良好催化活性和催化稳定性的可能原因.     

气液固三相磁稳定流化床的操作状态对反应结果的影响

以氮气、水、铁粉为气液固三相研究了三相磁稳定流化床的床层操作状态；以重整生成油的烯烃饱和加氢过程为体系，研究了铁粉与大比表面非晶态合金催化剂混合颗粒为固相的磁稳定流化床中床层操作状态对反应结果的影响。找到了有利于气液固三相反应的磁稳定流化床床层操作状态     

硝基苯催化加氢制苯胺的技术概况

介绍了硝基苯加氢制苯胺的技术概况,包括固定床加氢法、液相加氢法和流化床加氢法,对各工艺的优缺点进行了评述,并叙述了硝基苯加氢制苯胺催化剂的发展情况。     

SULFUR UPTAKE AND RELEASE BY Mo AND Co-Mo CATALYSTS AS STUDIED BY H235S RADIOTRACER

Sulfur uptake by reduced Mo0₃ and CoMoO₄ catalysts when passing H₂³⁵S pulses was measured. Also, the release of labelled sulfur was monitored when thiophene and cyclohexanol pulses were reacted over these catalysts. The sulfur release was about 20% of the retained amount in the H₂S/thiophene system. Here the conversion of thiophene in HDS was inversely proportional with the amount of irreversibly retained sulfur. A few pulses of cyclohexanol could stop sulfur uptake indicating that oxygen can be more firmly held by the catalyst than sulfur. All these arc in favor of interpreting the active sites as anion vacancies. @KEYWORDS: Catalysts, Sulfur, Radiotracer, Mo and Co-Mo Catalysts.