癸二睛加氢制癸二胺骨架镍催化剂的研究

本文介绍了癸二脯加氢制癸二胺用骨架镍催化剂的制备方法、活化条件,以及反应温度、压力、接触时间等因素对转化率的影响,揭示了骨架镍催化剂的反应特性和用于癸二脑加氮的最佳操作条件。     

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.     

Raney镍上松香催化加氢反应动力学研究

以松香为原料、Raney镍为催化剂和200#油为溶剂进行松香催化加氢反应研究。在消除松香加氢过程内外扩散影响的条件下,利用毛细管气相色谱法在线跟踪分析压力为5.0 MPa、温度为423~453 K下反应物浓度随时间的变化关系,对反应过程进行拟均相动力学研究,结果表明,松香催化加氢的反应速率与枞酸浓度呈0.5级反应,其动力学方程为r=5.68×105e-7.T5997c0A.5,表观活化能为63.18 kJ/mol。     

Kinetics of Liquid‐Phase Hydrogenation of Iso‐valeraldehyde to Iso‐amyl Alcohol Over A Ru/Al2O3 Catalyst

The liquid‐phase catalytic hydrogenation of iso‐valeraldehyde to iso‐amyl alcohol was studied in a slurry reactor. The kinetics of liquid‐phase hydrogenation of iso‐valeraldehyde over a 5% Ru/Al₂O₃ catalyst was studied in the range of temperature 373‐393 K and H₂ pressure 0.68‐2.72 MPa using 2‐propanol as the solvent. The selectivity to iso‐amyl alcohol was 100%. The kinetic data were analyzed using a simple power law model. A single site Langmuir‐Hinshelwood type model suggesting dissociative adsorption of hydrogen and surface reaction as the rate‐controlling step provided the best fit of the experimental data. The catalyst could be reused thrice without any loss in activity.     

木糖Raney-Ni催化加氢本征反应动力学

用细粉末Ｒａｎｅｙ－Ｎｉ催化剂研究了木糖水溶液加氢的本征反应动力学。在考察的温度（３７３～３９３Ｋ）、压力（１～６ＭＰａ）和木糖浓度（０．０２～１．３ｍｏｌ／ｄｍ３）范围内,速率与木糖浓度成１级。氢压低于４～５ＭＰａ时,符合Ｌａｎｇｍｕｉｒ－Ｈｉｎｓｈｅｗｏｏｄ形式的方程,用非线性优化法关联其参数,得到本征速率方程。反应机理推测为吸附氢原子与吸附木糖分子反应,表面反应生成的中间物被木糖解吸而成产物是控制步骤。３７３Ｋ以上在高压区出现的速率剧增现象可能与低能吸附位的激活有关     

非晶态雷尼镍催化剂低温催化生物油模型化合物加氢的研究

采用非晶态雷尼镍催化剂,在高压反应釜内对二丙酮醇、糠醛、苯酚和愈创木酚等生物油模型化合物进行低温催化加氢实验,研究了模型化合物催化加氢特性、反应机理以及催化剂性质。实验结果表明:温度是影响此类催化剂活性的最主要因素,温度过高容易导致催化剂晶化而降低催化活性;在反应温度180℃、压力3MPa、反应时间4 h以及催化剂量8%(wt)时,模型化合物的转化率和饱和醇的选择性分别达到100.00%和97.74%以上;在此反应条件催化真实生物油的体系中,饱和醇的收率达到44.00%,p H从4.08升至5.13;通过对模型反应机理的探讨,得出模型主要通过两种加氢方式进行:即不同化合物分别以其O上的孤对电子选择性地与催化剂上的两种活泼态H(弱吸附的Ni-H、游离的原子态氢)进行加氢反应,完成催化加氢过程。     

采用骨架钴和骨架镍催化剂加氢还原制备糠醇的研究

从钼、铬、铜和铁中筛选金属铬和铁作为助催化剂加入骨架钴或骨架镍催化剂,铬和铁的量分别为催化剂质量的３％和１％。在１００～１２０℃、１０～１２ＭＰａ条件下,用上述骨架钴或骨架镍催化剂在乙醇溶剂中,氢化还原糠醛制备糠醇。用骨架镍催化剂,反应产物含有７８５％的糠醇和１９６％的四氢糠醇;用骨架钴催化剂,反应产物含有９８８％的糠醇和０８％的四氢糠醇,收率９４％。在无乙醇溶剂条件下,反应产物含有９０５％的糠醇、０３％的四氢糠醇和９２％的糠醛。在１８０℃条件下,反应产物含有９０８％的糠醇和８９％的四氢糠醇。     

Hydrogenation of m‐dinitrobenzene to m‐phenylenediamine over La2O3‐promoted Ni/SiO2 catalysts

BACKGROUND: Liquid‐phase catalytic hydrogenation of m‐dinitrobenzene is an environmentally friendly routine for m‐phenylenediamine production. The key to increasing product yield is to develop catalysts with high catalytic performance. In this work, La₂O₃‐modified Ni/SiO₂ catalysts were prepared and applied to the hydrogenation of m‐dinitrobenzene to m‐phenylenediamine. The effect of La₂O₃ loading on the properties of Ni/SiO₂ was investigated. The reaction kinetic study was performed in ethanol over Ni/3%La₂O₃–SiO₂ catalyst, in order to clarify the reaction mechanism of m‐dinitrobenzene hydrogenation. RESULTS: It was found that the activity of the silica supported nickel catalysts is obviously influenced by La₂O₃ loading. Ni/3%La₂O₃–SiO₂ catalyst exhibits high activity owing to its well dispersed nickel species, with conversion of m‐dinitrobenzene and yield of m‐phenylenediamine up to 97.1% and 94%, respectively. The results also show that Ni/3%La₂O₃–SiO₂ catalyst can be reused at least six times without significant loss of activity. CONCLUSION: La₂O₃ shows strong promotion of the effect of Ni/SiO₂ catalyst for liquid‐phase hydrogenation of m‐dinitrobenzene. La₂O₃ loading can affect the properties of Ni/SiO₂ catalyst. Based on the study of m‐dinitrobenzene hydrogenation kinetics over Ni/3%La₂O₃–SiO₂ catalyst, a possible reaction mechanism is proposed. Copyright © 2009 Society of Chemical Industry     

缚酸剂对Raney Ni催化氢解TPD制1,3-丙二醇的影响

甘油的间接氢解是新近发展的制备1,3-丙二醇的方法.研究发现甘油的间接氢解中间体TPD(2-对甲苯磺酰氧基-1,3-丙二醇)加氢过程产生的对甲苯磺酸腐蚀催化剂,导致催化剂无法重复利用.为了避免催化剂被腐蚀,选用几种缚酸剂,研究了缚酸剂对TPD加氢反应的影响,通过单因素实验考察了温度、压力和催化剂(Raney Ni)用量对反应的影响,并对反应机理作了讨论.结果表明:三乙胺作为缚酸剂时较优的反应条件为:温度100℃,压力4 MPa,催化剂用量2.0 g(TPD质量的57%),在此反应条件下,TPD转化率为89.1%,1,3-丙二醇的选择性为33.7%.催化剂重复实验结果表明加入缚酸剂能在一定程度上保护催化剂.     

雷尼镍催化氢化法制备吲哚-2-甲酸

以邻硝基甲苯和草酸二乙酯为起始原料,合成邻硝基苯丙酮酸乙酯的乙醇碱性溶液,再用雷尼镍催化剂,在60~70℃、1.5 MPa压力下,用催化氢化法合成了吲哚-2-甲酸,总收率为70%(以邻硝基甲苯计算),用熔点、NMR、GC-MS谱图表征了该化合物。雷尼镍催化氢化方法合成吲哚-2-甲酸成本较低、后处理简单、无环境污染。     

改性Raney Ni催化剂用于加氢合成间苯二甲胺

采用改性RaneyNi催化剂 ,研究了溶剂、温度、压力、催化剂用量对间苯二甲腈 (IPN)加氢合成间苯二甲胺 (m XDA)反应的影响。结果表明 ,该催化剂在以甲醇、甲苯为混合溶剂 ,V(甲醇 )∶V(甲苯 )=1∶2 ,当m(溶剂 )∶m(IPN) =3∶1,反应温度 70℃、压力 6 0～ 7 0MPa、催化剂用量为原料质量 10 %时 ,IPN转化率接近 10 0 % ,m XDA收率达 97%。失活催化剂经再生 ,即能恢复其性能。     

糠醛液相加氢制糠醇骨架钴催化剂反应动力学研究

采用合金架钴催化剂在间隙高压反应釜中进行了糠醛液相加氢反应动力学及失活动力学的研究。提出了该反应的动力学及失活动力学的数学模型，并求得了该反应的反应级数、反应活化能值、反应速率常数及失活速率常数值，还测得了钴催化剂的使用寿命。     

在工业镍催化剂上苯气相加氢反应动力学

在常压下,应用内循环式无梯度反应器,研究了在国产工业镍催化剂上苯气相加氢的本征动力学.假设催化剂表面上存在两类不同的活性中心,氢及苯各自吸附在相邻的不同类型的活性中心上,设第一个氢原子加入苯环的步骤为反应速率控制步骤,据此以导出反应的动力学方程,与实验数据颇相符合,平均偏差6.1%.测得的本征反应活化能为13.1kcal/mol.苯的吸附热为9.84kcal/mol,与不存在化学反应时的测定结果相接近.     

Chemoselective Hydrogenation of α,β‐Unsaturated Nitriles

The chemoselective hydrogenation of cinnamonitrile to 3‐phenylallylamine proceeds with up to 80% selectivity at conversions of >90% with Raney cobalt and up to 60% selectivity with Raney nickel catalysts. Best results were obtained with a doped Raney cobalt catalyst (RaCo/Cr/Ni/Fe 2724) in ammonia saturated methanol at 100 °C and 80 bar. Major problems are the formation of hydrocinnamonitrile and of secondary amines, and overreduction to 3‐phenylpropylamine. Important parameters are the catalyst type and composition, the solvent type and the presence and concentration of ammonia. The catalytic system tolerates functional groups like OH, OMe, Cl, CO, but not aromatic nitro groups. Preliminary experiments indicate that other unsaturated nitriles with di‐ or trisubstituted CC bonds are also suitable substrates.     

Maltose hydrogenation to maltitol over industrial Raney Ni catalyst: Kinetics and mechanism

The kinetics and mechanisms of selective maltose hydrogenation over Raney Ni remain poorly understood, which hinders the industrial advancement of maltitol production for biorefining. Herein, the impact of hydrogenation conditions and in-depth mechanistic characterizations were carefully investigated in this research. Optimization of reaction conditions illustrated that maltitol formation was favored by moderate reaction temperatures (≤130°C), high hydrogen pressures (>7 MPa), and near-neutral sodium phosphate buffer (pH = 6.47). Kinetic studies demonstrated the E_a of 45.5 kJ/mol for the hydrogenation of maltose. The in situ IR revealed that the hydrogenation of maltose over Raney Ni occurs in the order of ring opening and adsorption via CO of the aldose form followed by hydrogenation. The UV–vis spectra demonstrated the near-neutral setting (pH = 6.47) promoted the production of open-chain aldose conformation and selective CO hydrogenation to the corresponding alcohols. The present study on concentrated-maltose hydrogenation paves the way for the industrial development of maltitol manufacturing.     

以Pd/C为催化剂的松香加氢本征动力学

在温度403~433K,压力3.0～7.0MPa下,研究了以Pd/C为催化剂的松香催化加氢本征动力学,为工业反应过程的开发和操作提供了理论依据.通过减少催化剂粒度和提高搅拌转速,以消除内外扩散的影响,在松香加氢反应过程中,在线跟踪了反应物和产物浓度随反应时间的变化关系.根据实验数据,采用EVIEWS软件对10个可能的反应机理模型进行筛选,认为最可几的反应机理为松香中的主要成分枞酸分子不吸附,枞酸分子与催化剂表面上被吸附的氢原子进行反应,氢原子的吸附为控制步骤;其反应动力学方程为, 据此导出反应速率常数和吸附平衡常数分别为 (Hk =5.695exp((2498.5/T), bs =9.4(10(3exp(1920.8/T).     

KT-02负载型镍催化剂用于对硝基苯酚催化加氢

以KT-02新型Ni/SiO2催化对硝基苯酚加氢制备对氨基苯酚,考察了温度、压力、搅拌速度等因素对反应的影响,并对催化剂进行了套用实验。实验表明,以甲醇为溶剂,加入8%催化剂,在90-95℃、1.5 MPa氢压条件下反应4.5 h,对硝基苯酚转化率和对氨基苯酚选择性均可达98%,催化剂套用8次以上。     

Cr-Cu硅胶催化间硝基甲苯气相制备间甲苯胺

用固定床反应器作为气相加氢装置,将自制Cu硅胶催化剂用于间硝基甲苯催化加氢制备间甲苯胺的反应。通过考察Cu含量以及助剂N i、Co、Cr、Mn对催化剂性能的影响,筛选出催化性能最佳的Cr-Cu硅胶催化剂。分析了各反应因素对间甲苯胺产率的影响:当反应时间1.5 h,反应温度270℃,氢气与间硝基甲苯摩尔比为9∶1时,间甲苯胺的产率达到最大值99.4%,此时Cr-Cu硅胶催化剂的最大负荷为1.1 mL/(h.mL-cat.),满足工业化应用水平。目前该工艺的中试生产线正在805厂调试中。     

Hydrogenation of heptaldehyde to heptyl alcohol with nickel catalysts

Hydrogenation of heptaldehyde to heptyl alcohol was studied with W2 Raney nickel catalyst, prepared in the laboratory, commercial Raney nickel catalyst and Rufert nickel catalyst by varying temperature, catalyst concentration, hydrogen pressure and reaction time. The products were analyzed by gas-liquid chromatography on SE-30 column. The optimum conditions found for quantitative conversion (99.6%) of heptaldehyde to heptyl alcohol were: temperature, 100°C, W2 Raney nickel catalyst concentration, 2% based on heptaldehyde (w/w), hydrogen pressure, 145 psig and reaction time, 1 h. IICT Communication No. 3085.     

雷尼镍催化剂在己二胺生产中的应用研究

介绍了己二胺生产中用高活性雷尼镍催化剂的制备过程,确定了催化剂活性与水洗水流量、活化合金粉用量的对应关系。并探讨了在己二胺生产中最佳的催化剂浓度。