葡萄糖加氢制山梨醇催化剂研究及发展趋势

介绍了葡萄糖加氢生产山梨醇用催化剂的国内外研究现状,提出了催化剂的发展趋势是由Raney镍向多元改性Raney镍发展,由多元Raney镍催化剂向负载型贵金属催化剂发展,由晶态催化剂向非晶态催化剂发展,并指出非晶态储氢合金是一种很有发展潜力的催化剂。     

山梨醇用Raney 镍催化剂活化条件的研究

对葡萄糖加氢制山梨醇用Raney镍催化剂的活化条件进行了研究,用丙酮法测定催化剂的加氢活性,考察了活化时NaOH的用量、活化温度及活化时间对Raney 镍催化剂加氢活性的影响.实验结果表明,制备Raney镍催化剂较好的活化条件为:NaOH/Al(物质的量比)为4.5,活化温度50 ℃,活化时间为1.5 h.     

山梨醇用Raney镍催化剂活化条件的研究

对葡萄糖加氢制山梨醇用Raney镍催化剂的活化条件进行了研究，用丙酮法测定催化剂的加氢活性，考察了活化时NaOH的用量、活化温度及活化时间对Raney镍催化剂加氢活性的影响。实验结果表明，制备Raney镍催化剂较好的活化条件为：NaOH/Al（物质的量比）为4．5，活化温度50℃，活化时间为1．5h。     

钼改性雷尼镍催化剂的葡萄糖加氢性能

Mo改性雷尼镍是葡萄糖加氢制备山梨醇工业中重要的催化剂。考察了不同Mo含量雷尼镍催化剂的葡萄糖加氢性能。结果表明,Mo改性雷尼镍催化剂的活性和稳定性得到大幅提高,探讨了Mo改性雷尼镍催化剂活性和稳定性提高的原因。Mo改性雷尼镍催化剂活性和稳定性提高的原因是改性催化剂中氧化态的Mo可以作为L酸吸附中心,有利于葡萄糖在催化剂上的吸附,从而提高催化剂活性;Mo的存在,减少了雷尼镍催化剂在反应过程中Al的流失量,是催化剂稳定性提高的主要原因。     

己二腈加氢制备己二胺催化剂的研究进展

简述了己二腈催化加氢的反应机理;根据催化剂形式的不同;综述了己二腈加氢制备已二胺催化剂的研究进展;介绍了Zlegler型催化剂及贵金属络合物均相催化剂、雷尼镍(Raney Ni)型催化剂及非负载型多相催化剂在己二腈催化加氢制备己二胺的应用及其优缺点;详述了负载型催化剂的研究进展及加氢效果;指出工业生产中以Raney Ni型催化剂为主,但使用寿命及环保方面限制其发展,而负载型催化剂在己二腈催化加氢具有较好的应用前景;建议今后应进一步探索己二腈催化加氢中的不同产物生成机理,改进活体的负载方式及助催化剂的研究。     

镍基催化剂加氢还原氯代硝基苯时脱氯机制的研究

Ni-B/SiO2非晶态合金对一系列氯代芳烃硝基化合物进行加氢,脱氯顺序依次为:2-氯-5-硝基甲苯>邻氯硝基苯>间氯硝基苯=对氯硝基苯>2,5-二氯硝基苯。将Ni-B/SiO2非晶态合金和Raney Ni催化加氢邻氯硝基苯进行了对比,发现在—NO2转化成—NH2的反应终了之前,用非晶态镍催化剂的脱氯速度小于用Raney Ni催化剂的脱氯速度,但加氢反应终了之后,在非晶态镍催化剂上的脱氯速度大于Raney Ni催化剂上的脱氯速度。镍基催化剂的软硬度是催化剂选择性好坏的主要原因,镍基催化剂软度大有利于催化剂选择性的提高。     

纳米镍加氢催化剂的研究与发展

本文介绍了镍基在加氢反应中的催化原理,通过比较、分析纳米镍催化剂与传统的Raney镍催化剂,突出了纳米镍催化剂作为新型镍催化剂有着很大的发展前景,是未来镍催化剂的重要发展方向,重点介绍了溶胶-凝胶法等离子体法,以及工业中常用的制备镍催化剂的方法,如羰基法等,同时对这些制备方法进行了分析评价。     

石油树脂应用与改性研究进展

介绍了C_5~C_9石油树脂的分类、制备、应用及发展概况,综述石油树脂的催化加氢改性技术和化学改性技术,石油树脂的催化加氢改性是近年来发展较迅速的领域,其技术的关键是针对树脂原料的不同类型找到合适的催化加氢催化剂和加氢条件,重点介绍石油树脂催化加氢工艺和使用的催化剂。目前,研究的树脂加氢催化剂主要有贵金属钯系列催化剂、负载型镍系列催化剂和新型磷化物系列催化剂,而石油树脂的化学改性技术关键在于向石油树脂分子中引入合适的活性基团。石油树脂经改性后,应用范围扩大,经济效益大幅增加。     

3种镍基催化剂对苯乙酮的催化加氢对比研究

制备了Ni—B／SiO2非晶态催化剂、Raney Ni催化剂和漆原镍催化剂,采用XRD、SEM等对非晶态特征进行表征。分别用这3种镍基催化剂对苯乙酮进行催化加氢实验,实验表明,Ni—B／SiO2非晶态催化剂的催化活性和稳定性明显优于其他两种镍基催化剂。     

葡萄糖催化加氢制山梨醇的动力学研究

本文进行了葡萄糖在拉内镍(Raney nickel)存在下的加氢反应动力学研究,反应温度383～413K,反应压力2.0～6.OMPa.根据实验结果筛选出一个合适的反应模型,即为吸附在催化剂表面上的葡萄糖分子和氢分子间进行的反应,产物山梨醇的脱附为速度控制步骤.本征动力学方程为;r=kK_Gc_GaK_Hp_H/(1+K_Gc_G+aK_Hp_H)     

Sn改性Raney Ni催化分解N,N-二甲基甲酰胺的研究

为了研究Sn含量和还原温度对Sn-RaneyNi催化剂的物理化学结构和催化分解N,N-二甲基甲酰胺(DMF)活性的影响,利用沉淀法制备了一系列不同Sn含量的Sn-RaneyNi催化剂,采用N2物理吸附、X射线衍射(XRD)和氢气程序升温还原(H2-TPR)等方法对不同Sn含量和不同还原温度制得的Sn-RaneyNi催化剂的比表面积、物相组成和还原性能进行了表征。以N,N-二甲基甲酰胺(DMF)为模型化合物,对Sn-RaneyNi催化剂的催化分解活性进行了评价。XRD表征结果表明,n(Sn)/n(Ni)为0.1的催化剂分别在723K和823K下还原生成Ni3Sn4和Ni3Sn合金晶相;n(Sn)/n(Ni)为0.15的催化剂在723K下还原形成Ni3Sn2合金晶相。H2-TPR结果表明,Ni-Sn合金的形成削弱了Sn和Ni与氧的结合能,使得Sn和Ni的还原峰向低温移动。催化分解DMF实验结果表明,当n(Sn)/n(Ni)为0.1、还原温度为723K时,Sn修饰RaneyNi催化剂能够将高浓度DMF(5%(wt))完全分解(分解率达100%),氢气的选择性达到86.8%。     

Raney Ni催化剂降解含酚废水制氢研究

为了实现生物难降解高毒性的含酚废水的活性和资源化利用,利用碳氢有机化合物与水之间的水相重整反应技术降解含酚废水制氢。考察了温度、酚浓度和液体空速等对Raney Ni催化剂或Sn修饰的Raney Ni（Sn—Raney Ni）降解含酚废水制氢性能的影响。结果表明,在温度543K,压力5．5MPa,酚浓度1mmol／L和液体空速1．42h^-1。下,含酚废水通过水相重整过程可以一步生成H。和CO2等气相小分子,酚的降解率和制氢的选择性分别达到100％和98．6％：Sn修饰的Raney Ni比Raney Ni催化剂具有更好的降解含酚废水制氢的性能。为生物难降解有机废水的处理和含酚废水制氢资源化提供了一种新的方法。     

载体对Ni基催化剂催化蒽醌加氢活性的影响

研究了载体对Ni基催化剂用于蒽醌法制备H₂O₂加氢活性的影响,同时对比了骨架镍的催化活性,考察Ni负载量对催化剂活性的影响。结果表明,负载在SiO₂上的催化剂比负载在γ-Al₂O₃上的催化活性高,对于Ni/SiO₂催化剂,Ni负载质量分数28.57%～50%时,加氢活性较高,按单位质量纯Ni上H₂O₂产量计算,Ni/SiO₂优于骨架镍催化剂,Ni负载量过高时,加氢活性降低。2-乙基蒽醌在Ni/SiO₂催化剂上的加氢为结构敏感型反应,当Ni在SiO₂的分散度达到约18%时,催化活性较佳。     

Hydrogenation of stigmasterol

Hydrogenations of stigmasterol over 5% Pd/C, 5% Ru/C, Pt, Raney Ni, Raney Co, Ni/kieselguhr, and tris(triphenylphosphine)chlororhodium catalysts and with diimide generated from hydrazine andp-toluenesulfonylhydrazide were studied to determine the best conditons for the selective reduction of the Δ²² double bond. The best results (maximum stigmasterol reduction, minimum stigmastanol formation) were obtained with Raney nickel at room temperature and atmospheric pressure. Contribution No. 1889 University of Arizona Agricultural Experiment Station.     

Structured Raney Nickel Catalysts for Liquid‐Phase Hydrogenation

Structured catalysts consisting of metal sheets on which Raney nickel was deposited by the thermal spraying method were tested for the liquid‐phase hydrogenation of glucose to sorbitol and 2‐nitrotoluene to 2‐methylaniline, used as model reactions. Catalytic tests performed in a bench‐scale (1 L) reactor showed that the catalytic activity of Raney Ni sheets is significantly higher than the one of the pellets used for fixed‐bed applications, but lower than the activity of the powder catalyst used in slurry mode. The activity could be significantly improved when applying a two‐phase co‐current flow through a monolith. In this case, the activity was superior to the one obtained with the slurry catalyst. These results confirm the potential of Raney Ni monoliths as structured catalysts.     

间苯二甲腈液相加氢制间苯二甲胺催化剂的研究

间苯二甲腈液相催化加氢制间苯二甲胺的Ｒａｎｅ６Ｎｉ催化剂用化学 原法进行改性,经过大量催化剂筛选,结果表明,在同时引入ａ、ｇ双元素改性后,反应速率明显加快,ｍ－ＸＤＡ的收率从改性前的８５．１％提高到９７．０％,寿命由原来的１－２次提高到５次;失活的催化剂经再生,可恢复其活性。     

H2 production by selective decomposition of hydrous hydrazine over Raney Ni catalyst under ambient conditions

A noble metal‐free catalyst, Raney Ni, exhibited > 99% selectivity toward H₂ for hydrous hydrazine decomposition in basic solution at 30^°C. The particle size of the initial Ni‐Al alloy and the concentration of additional alkali influenced the H₂ selectivity on Raney Ni catalysts. This convenient route provides great potential for industrial application of hydrous hydrazine as a promising hydrogen storage material. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4297–4302, 2013     

Physicochemical and catalytic properties of iron‐promoted Raney‐nickel catalysts obtained by mechanical alloying

Raney‐type catalysts were prepared by means of a two‐step procedure: (i) mechanical alloying of the metals and (ii) alkaline aluminum leaching. Mechanical alloying is a novel alternative related to the synthesis of skeletal Ni catalysts. Catalysts characterization was performed by atomic absorption, X‐ray diffraction, electron microscopy, and Mössbauer spectroscopies. Textural studies were also carried out. Binary Al–Ni and ternary Al–Ni–Fe alloys were produced by mechanical alloying from pure metallic powders; in particular, the intermetallic α‐(AlNi) phase was formed with a fine microstructure as a non‐equilibrium phase; then, aluminum was selectively removed. After aluminum leaching the α‐(AlNi) phase was transformed into the more stable nickel fcc structure. The effect of iron addition to the Ni–Al catalysts depends on iron concentration and reduction temperature; both parameters determine catalysts composition and activity. This work reports physicochemical properties and benzene hydrogenation activity of these materials, compared with conventional catalysts obtained by melting and leaching.     

Raney Ni catalysts derived from different alloy precursors Part II. CO and CO2 methanation activity

Catalytic activity, in conjunction with reaction mechanism, was studied in the methanation of CO and CO₂ on three Raney Ni catalysts derived from different Ni-Al alloys using different leaching conditions. Main products were CH₄ and CO₂ in CO methanation, and CH₄ and CO in CO₂ methanation. Any other hydrocarbon products were not observed. Over all catalysts, CO methanation showed lower selectivity to methane and higher activation energy than CO₂ methanation. The catalyst derived from alloy having higher Ni content using more severe leaching conditions, namely higher reaction temperature and longer extraction time, showed higher specific activity and higher selectivity to methane both in CO and CO₂ methanation. In CO and CO₂ methanation on Raney Ni catalyst, catalytic activity was seen to have close relation with the activity to dissociate CO This paper was presented at the 2004 Korea/Japan/Taiwan Chemical Engineering Conference held at Busan, Korea between November 3 and 4,2004.