糠醛加氢制2-甲基呋喃催化剂的研究进展

本文综述了糠醛加氢制2-甲基呋喃所用的3类催化剂铬铜催化剂、无铬铜类催化剂、非晶态合金催化剂的近期研究进展。重点介绍了各类催化剂的制备及其催化性能,并对相关研究进行了评述。同时对糠醛加氢制备2-甲基呋喃催化剂的研究进行了展望。     

挂式四氢双环戊二烯合成工艺研究进展

以双环戊二烯为原料,通过加氢、异构化两个过程得到一种高能量密度燃料——挂式四氢双环戊二烯(exo-THDCPD)。综述了exo-THDCPD制备过程涉及的技术现状,包括反应原理、工艺路线、主要技术参数等内容。重点介绍了加氢与异构化催化剂种类及制备方法、加氢与异构化工艺流程的研究进展。总结出非贵金属合金催化剂为加氢催化剂的研究重点;延长固载化Al Cl3催化剂的使用寿命、提高分子筛催化剂的抗积碳能力、降低离子液体催化剂的生产成本是异构化催化剂的3个研究方向;提高双功能催化剂的选择性对"一锅法"制备exo-THDCPD意义重大;液相串联工艺有望实现exo-THDCPD的连续化工业生产。     

The hydrogenation of triglycerides using supported alloy catalysts. I. Silica-supported Ni—Ag catalysts

Silica-supported Ni-Ag catalysts with a loading of 2·1·0.6% (w/w) total metal have been prepared using the precursors nickel dimethylglyoxime and silver nitrate by means of a simple impregnation method. The resulting catalysts were activated by calcination at 260°C in air, followed by hydrogen reduction at 450°C. They were then employed for soyabean oil hydrogenation at 1 bar H2 pressure and 160°C in a stirred batch reactor. Characterisation of the catalysts using temperature-programmed reduction and electron microscopy indicated that alloying of nickel and silver had occurred, but metal particle composition, for a given overall composition, varied with metal particle size and smaller metal particles were nickel rich. The hydrogenation activity and selectivity measurements revealed that the catalysts were more active and selective than a commercial nickel catalyst. Furthermore, the specific activities of the alloy catalysts were a maximum for alloys in the range 70–90 at. % Ni. However, the supported alloy catalysts also gave rise to greater trans isomerisation than the commercial catalyst. This is attributed to hydrogen deficiency caused by large triglyceride molecules blocking hydrogen chemisorption on small nickel particles (10–50 Å in diameter), leading to enhanced cis-trans isomerisation.     

油脂在镍基催化剂上氢化性能的研究

研究由共沉淀方法制备的镍基催化剂上大豆色拉油加氢活性,测定氢化反应温度180℃,反应压力0．8MPa,反应时间120min,催化剂用量4％g／mL、搅拌转速360r／min条件下氢化油脂的碘值、折光指数、熔点数据,考察改变镍铝比、添加助剂铜铁镧等对催化剂在油脂氢化过程中活性的影响,镍基催化剂有较好的加氢活性。     

Catalyst preparation and support effects for triglyceride hydrogenation over supported nickel

Nickel catalysts have been prepared by impregnation and precipitation methods on silica and charcoal. Metal loadings were in the range 1–40% w/w Ni on the support. The catalysts were investigated by temperature programmed reduction (TPR) and subsequently reduced in the temperature range 200–500°C. Metal surface areas were measured via H₂ and CO chemisorption and limited studies of the catalysts were carried out using X-ray photon spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) to determine the chemical and physical state of the nickel after reduction. Reduced catalysts were employed for triglyceride (soya bean oil) hydrogenation (1 atmos H₂, 160°C) in a stirred reactor (1000 rpm) and reaction rates (catalyst activity) and product distributions were determined. Charcoal supported catalysts were active and zero valent nickel was detected after reduction. However, surface areas were variable, the performance of such catalysts being affected by pore effects, agglomeration and possibly nickel–charcoal interaction. Silica supported precipitated catalysts were of relatively high activity and metal surface if methanol washed before activation and inactive (irreducible) if only water washed. Although silica supported precipitated catalysts were more active per unit weight of metal than charcoal supported counterparts, they were less active per unit metal area and gave rise to greater trans-acid production. This may be due to triglyceride molecules excluding hydrogen from small nickel crystallites.     

二硝基甲苯加氢制甲苯二胺催化剂的研究进展

综述了二硝基甲苯液相加氢合成甲苯二胺催化剂的研究进展,并介绍了(Pd+Pt)/C等贵金属催化剂、雷尼镍催化剂、负载型镍基催化剂、非晶态镍催化剂和漆原镍催化剂的最新研究成果。通过对比上述各催化剂在生产成本、制备工艺及催化二硝基甲苯加氢性能等方面的优缺点,发现非晶态镍催化剂不但价格低廉,而且在1 MPa低压二硝基甲苯液相加氢的反应中表现出与(Pd+Pt)/C工业催化剂相似的活性和选择性,是替代二硝基甲苯液相加氢贵金属和雷尼镍工业催化剂的首要选择;漆原镍催化剂制备工艺简单,价格低廉,且在众多的加氢反应中表现出与骨架镍催化剂相似的催化性能,也具有较大的工业化潜质。     

钌基催化剂在加氢反应中的应用

钌基催化剂在低温和低压等温和条件下具有优异的催化性能,因而广泛应用于各种反应中。文章介绍了钌基催化剂的研究现状,着重探讨了其在加氢反应中的应用和研究进展,包括载体材料、前驱体和助剂对催化剂性能的影响。所涉及的反应包括:CO2加氢合成甲酸、CO/CO2甲烷化、苯加氢制环己烯、苯胺加氢制环己胺与二环己胺、多元醇加氢制备二元醇、葡萄糖加氢合成山梨醇等,并对它的应用前景进行了展望。     

含聚双烯烃链节聚合物的加氢

介绍了目前用于含聚双烯烃链节的聚合物加氢的催化剂的种类,讨论了SBS加氢的机理及加氢动力学的研究进展。     

Acetylene Hydrogenation on Au-Based Catalysts

Hydrogenation of acetylene has been investigated on Au/TiO₂, Pd/TiO₂ and Au-Pd/TiO₂ catalysts at high acetylene conversion levels. The Au/TiO₂ catalyst (avg. particle size: 4.6 nm) synthesized by the temperature-programmed reduction-oxidation of an Au-phosphine complex on TiO₂ showed a remarkably high selectivity to ethylene formation even at 100% acetylene conversion. Au/TiO₂ prepared by the conventional incipient wet impregnation method (avg. particle size: 30 nm), on the other hand, showed negligible activity for acetylene hydrogenation. Although the Au catalysts showed a high selectivity for ethylene, the acetylene conversion activity and catalyst stability were inferior to the Pd-based catalysts. Au-Pd catalysts prepared by the redox method showed high acetylene conversions as well as high selectivity for ethylene. Interestingly Au-Pd catalysts prepared by depositing Pd via the incipient wetness method on Au/TiO₂ showed very poor selectivity (comparable to mono-metallic Pd catalysts) for ethylene. High-resolution transmission electron microscopy (TEM) studies coupled with energy dispersive X-ray spectroscopy (EDS) showed that while the redox method produced bimetallic Au-Pd catalysts, the latter method produced individual Pd and Au particles on the support.     

Silica-supported alloy catalysts for triglyceride hydrogenation: The preparation and properties of Pd–Ag and Pd–Ni systems

The binary metal systems Pd–Ag and Pd–Ni have been prepared on a silica support with a total metal loading of 2.5% (w/w). About a dozen catalysts were prepared in each series covering the range 0–100 at. % Pd. The catalysts were characterised by a number of techniques, principally temperature programmed reduction, differential scanning calorimetry and metal surface area measurement. The catalyst activity and selectivity were measured for the hydrogenation of soya bean oil in both stirred and shaken batch reactors at 1 atm H₂ pressure in the temperature range 100–160°C. The characterisation techniques provided strong evidence of alloying for both series of catalysts. The activity and selectivity measurements also provided supporting evidence of alloying, and the Pd–Ag system exhibited an activity maximum in the 90–100 at. % Pd range, while the Pd–Ni system maintained constant activity for alloys containing 0–60 at. % Ni. Trans-acid formation was suppressed by lower reduction temperature, and linolenate removal was improved at lower temperatures. However, it also appears that reaction rates were dominated largely by triglyceride diffusion effects.     

Structure and catalytic properties of Cu-Ni bimetallic catalysts for hydrogenation

The dependence of catalytic activity and selectivity of Cu-Ni bimetallic catalysts for oil hydrogenation on CuNi ratios have been investigated while they were reduced at low temperature (230 °C). Two maxima occurred at Cu₂Ni₁ and Cu₁Ni₃ in the activity-CuNi curve. Cu riched catalysts have higher selectivity than Ni riched ones, and may cause dehydrogenation and isomerization of linoleate at the beginning of the reaction. The structures of the catalysts reduced at different temperatures have been studied by means of XRD, XPS, EXAFS and FMR et al. The structure of the catalysts reduced at 230 °C can be described as an aggregate of Cu particles inlaid with Ni atoms and unreduced NiO, and the easily reduced Cu always segregates on the surface, while homogeneous solid solution particles can be formed in the case 400 °C being used as reduction temperature.     

预硫化加氢催化剂钝化的研究进展

钝化是预硫化加氢催化剂的一个重要处理步骤,介绍了预硫化催化剂的气体钝化、含氧烃钝化和涂覆剂钝化3种工艺,以及预硫化催化剂钝化的应用和研究进展。经过上述钝化工艺处理后．有效抑制了催化剂的自热或自发燃烧的特性,使预硫化催化剂的运输、存放、保管变得简单安全,这对大规模推广使用器外预硫化催化剂有着重要的意义。     

脂肪酸（或酯）加氢制脂肪醇催化剂进展及评述

论述了脂肪酸（或酯）加氢传统的工业催化剂，以及近年来开发进展的温和条件下的中压催化性能及评述。     

Parallel hydrogenation of 2,2‐dimethylol‐1‐butanal and formaldehyde over supported NiCr and CuCr catalysts

The hydrogenation kinetics of 2,2‐dimethylol‐1‐butanal (TMP‐aldol) and formaldehyde were studied over two commercial supported catalysts; NiCr on silica and CuCr on alumina. Both catalysts hydrogenated the aldol selectively to triol, but the kinetic trends differed widely. With the nickel catalyst, the aldol hydrogenation was not started before almost all of the formaldehyde was consumed from the bulk phase, whereas the copper‐containing catalyst hydrogenated aldol and formaldehyde in parallel. Rate equations for the hydrogenation of aldol and formaldehyde were derived from a competitive surface mechanism. Since formaldehyde retarded significantly the hydrogenation rate of aldol over NiCr, the kinetic model was modified in order to take into account the inhibitory effect of formaldehyde. With the modified model, the experimental data produced over the NiCr catalyst were rather well described. The data from the experiments over the CuCr catalyst followed pseudo‐first order kinetics remarkably well. Furthermore, the kinetic model without the inhibitory effect of formaldehyde was able to describe the governing trends of the data obtained over the CuCr catalyst. © 2002 Society of Chemical Industry     

Effect of Ag‐promotion on Pd catalysts by XANES

Pd L₃ near‐edge absorption measurements (XANES) were performed on four commercial acetylene hydrogenation catalyst samples, with and without the Ag promoter. The Pd L₃ edge XANES spectra showed that the Ag‐promoted catalysts have relatively weaker absorption peaks and they follow the same order as the relative commercial performances of the four catalysts studied in terms of selectivity in ethylene purification, which indicates that there are increases in the Pd d‐band electron densities due to the addition of Ag. These results provide a reasonable explanation for the observed improvement in selectivity of the Ag‐promoted acetylene hydrogenation catalysts. The Ag L₃ XANES spectra of the supported Pd–Ag catalysts indicate the absence of a white‐line feature which seems to suggest that the charge transferred from Ag to Pd may not be the d‐type. This revised version was published online in July 2006 with corrections to the Cover Date.     

磷、柠檬酸改性对MoW/Ni/Al2O3催化剂性质及加氢脱氮性能的影响

采用等体积浸渍法制备了以γ-Al₂O₃为载体,Ni、Mo、W为活性金属组分的三金属催化剂,考察了磷改性、柠檬酸改性以及磷-柠檬酸组合改性对催化剂性质、加氢脱氮性能和脱氮选择性的影响。通过NH₃-TPD、Py-IR、H₂-TPR、XPS和HRTEM对催化剂进行表征,结果表明：磷改性不但提高了催化剂的表面弱酸量,而且提高了金属的硫化性能,促进碱性氮和非碱性氮的脱除,但磷改性导致金属活性相的堆垛层数偏高、分散度下降;柠檬酸改性降低了催化剂活性金属氧化物的硫化温度,提高了催化剂的加氢活性,但对氢解性能基本没有影响,表现为非碱性氮脱除性能的提高;而磷-柠檬酸组合改性,不但提高了催化剂的氢解性能,而且改善了其加氢活性,使催化剂对焦化蜡油中碱性氮和非碱性氮的脱除率均得到大幅提升,分别达到80.1%、54.9%。     

Co/SiO2 catalysts prepared from Co2(CO)8 for CO hydrogenation into alcohols and hydrocarbons: characterization by magnetic methods and temperature-programmed hydrogenation

The hydrogenation of carbon monoxide over Co/SiO₂ catalysts obtained by reduction of precursors prepared by the reaction of dicobaltoctacarbonyl with silica gives rise to a mixture of alcohols and hydrocarbons. The chain growth probability for hydrocarbon synthesis is similar to that observed over conventional catalysts prepared by the ammonia method (=0.74) with a comparable metal dispersion (metal particle size 4 nm). Alcohol formation yields a smaller chain growth probability (=0.42). Magnetic measurements have shown that in the latter catalyst, small cobalt clusters (1 nm) are likely to be present together with the cobalt particles (4 nm), this observation reconciles apparently conflicting results from the literature. It has been speculated that alcohol formation might be related to the presence of these clusters according to a concerted mechanism. Furthermore, the observation of large amounts of acetates by temperature-programmed hydrogenation, not detected in hydrocarbon selective catalysts, suggests that they may play a role in ethanol synthesis.     

非晶态合金催化剂用于葡萄糖加氢制山梨醇的研究

采用石油化工科学院研制的非晶态合金催化剂进行葡萄糖加氢,考察了温度、压力、ｐＨ 值、剂糖比和反应时间等因素对加氢反应的影响,并与其它Ｒａｎｅｙ Ｎｉ 类催化剂进行了对比。结果表明,使用ＳＲＮＡ－３ 非晶态合金催化剂进行葡萄糖加氢,当反应温度为１３０ ～１４０℃、压力为５ ～９ＭＰａ、ｐＨ值为８．３５、剂糖质量比为１％ 、反应时间为７０～１２０ｍｉｎ 时,转化率可达１００％ ,产品色度好。ＳＲＮＡ－３ 催化剂的葡萄糖加氢活性好于Ｒａｎｅｙ Ｎｉ 催化剂,重复使用时,也可保持较高活性。     

国内清洁柴油加氢催化剂研究进展

综述了国内清洁柴油国Ⅴ标准加氢催化剂研究进展情况,目前,国内多家研究机构在柴油清洁生产方面都有自己独特的加氢催化剂及工艺,且达到了国际先进水平。中科院大连化物所的最新柴油加氢催化剂从性能到制备技术达到了国际领先水平。     

炔烃及二烯烃选择加氢催化剂的研究进展

综述了在炔烃和二烯烃选择加氢制烯烃过程中的催化剂的应用研究进展。