Hydrogenolysis of Glycerol to Propanediol Over Ru: Polyoxometalate Bifunctional Catalyst

Ruthenium-doped (5 wt%) acidic heteropoly salt Cs_2.5H_0.5[PW₁₂O₄₀] (CsPW) is an active bifunctional catalyst for the one-pot hydrogenolysis of glycerol to 1,2-propanediol (1,2-PDO) in liquid phase, providing 96% selectivity to 1,2-PDO at 21% glycerol conversion at 150 °C and an unprecedented low hydrogen pressure of 5 bar. Rhodium catalyst, 5%Rh/CsPW, although less active, shows considerable selectivity to 1,3-PDO (7.1%), with 1,2-PDO being the main product (65%).     

负载型Pt-Ni双金属催化剂上甘油氢解反应性能

甘油氢解转化是获得高附加值化学品的主要途径之一。通过浸渍法制备了γ-Al2O3负载Pt-Ni双金属的甘油氢解催化剂。采用X射线衍射(XRD)、氮气物理吸附、透射电子显微镜(TEM)、程序升温还原(TPR)以及X射线能谱分析(XPS)等手段对催化剂进行了表征。结果表明:在γ-Al2O3负载的Pt-Ni双金属催化剂中,Pt原子与Ni原子之间发生了相互作用并形成了Pt Ni合金簇,使得Pt-Ni双金属催化剂产生了协同作用,对乙二醇的选择性大大高于Pt/γ-Al2O3和Ni/γ-Al2O3等单金属组分催化剂。固定床反应器实验结果表明,在473 K和3.0 MPa氢气压力下,负载量为2%Pt-15%Ni/γ-Al2O3催化剂对乙二醇的选择性最高,达到28.4%,此时甘油的转化率为94.8%,1,2-丙二醇的选择性为58.2%。     

甘油氢解合成1,2-丙二醇铜锌铝催化剂的性能

采用共沉淀法制备了铜锌铝类水滑石前驱体,经焙烧和还原后制得铜基催化剂。采用XRD、H₂-TPR、H₂-TPD、NH₃-TPD和CO₂-TPD等表征手段并结合甘油氢解反应评价,研究了类水滑石前驱体的老化对催化剂结构和性能的影响,考察了反应条件对催化剂甘油氢解反应性能的影响。结果表明,老化有利于形成结构更为完整的类水滑石前驱体,但对铜物种的还原性能未造成显著影响。与由未老化前驱体制备的催化剂相比,由老化前驱体制备的铜锌铝催化剂具有较大Cu表面及较大酸量,但表面碱中心数量较低,从而该催化剂具有较好的甘油氢解活性及稳定性。在220 ℃、H₂压力3.0 MPa、n(H₂)/n(甘油)为18.9、甘油重时空速1.26 h^-1及质量分数为60%甘油水溶液的条件下,经老化前驱体制备的铜锌铝催化剂上甘油转化率接近100%、1, 2-丙二醇选择性约为96%。     

Influence of Parameters on Glycerol Hydrogenolysis over a Cu/Al2O3 Catalyst

The influence of technological parameters like hydrogen pressure, temperature, glycerol concentration in aqueous solution, amount of catalyst, stirring speed, and reaction time on glycerol hydrogenolysis to 1,2‐propanediol over a Cu/Al₂O₃ catalyst prepared by coprecipitation was investigated. Functions describing the process were glycerol conversion as well as selectivity to 1,2‐propanediol and to by‐products in the liquid and gas phase. The structure and properties of synthesized Cu/Al₂O₃ were characterized by X‐ray diffraction, energy dispersive X‐ray microanalysis, BET surface area, average pore volume, and pore diameter. Catalyst recycle studies were also performed.     

A Highly Efficient Catalyst Au/MCM-41 for Selective Oxidation Cyclohexane Using Oxygen

The liquid-phase highly efficient selective oxidation cyclohexane to cyclohexanol and cyclohexanone over Au/MCM-41 catalyst was carried out in a solvent-free system, which oxygen as the only oxidant and the reaction conditions are very moderate. The Au/MCM-41 was characterized by XRD, N₂adsorption/desorption, UV-Vis, XPS, and ICP-AES.     

The Promotion Effect of Cr on Copper Catalyst in Hydrogenolysis of Glycerol to Propylene Glycol

Binary Cu/Cr catalysts, containing various molar ratios of copper to chromium, were synthesized and their catalytic activities were examined for the hydrogenolysis of glycerol to propylene glycol. When catalyst containing Cu and Cr ratio of 1:2, it was mainly composed of CuCr₂O₄ phase. And it was found to have the highest catalytic activity in this reaction, due to its favorable reduction properties.     

A Tuneable Bifunctional Water‐Compatible Heterogeneous Catalyst for the Selective Aqueous Hydrogenation of Phenols

A water‐tolerant bifunctional heterogeneous catalyst is able to effectively catalyse the selective hydrogenation of phenol to cyclohexanone in water at atmospheric pressure and room temperature with >99.9% selectivity to cyclohexanone at phenol conversions >99.9%. The catalyst was found to be highly active and reusable, giving identical activities and selectivities after >5 uses. Moreover, this reported simple bifunctional catalyst is also able to hydrogenate a range of substituted phenols in high yields under the investigated aqueous conditions.     

甘油氢解制二元醇的研究进展

近年来,随着国内外生物柴油产业的快速发展,生成大量副产物甘油,合理利用过剩的甘油将有助于整个生物柴油产业的经济效益。本文针对以甘油为底物,催化氢解合成高附加值二元醇的研究进行了综述,介绍了甘油催化氢解成二元醇的反应机理和研究现状,并对发展前景作了展望。     

Direct Hydrogenolysis of Highly Concentrated Glycerol Solutions Over Supported Ru,Pd and Pt Catalyst Systems

Abstract  

The evaluation of supported precious metal catalysts, in combination with and without solid acids, for the hydrogenolysis of highly concentrated glycerol solutions, with the aim to produce lower alcohols, in particular 1-propanol was studied. GCMS analysis of the product mixtures obtained has shed some light on the possible mechanism leading to unwanted condensation products, as well as the composition of these compounds.     

Resin-Based Catalysts for the Hydrogenolysis of Glycerol to Propylene Glycol

Three alkysulfonic resins were obtained by co-polymerization of 2-acrylamido-2-methyl-propansulfonic acid with N,N-dimethylacrylamide and ethylene dimethacrylate (the cross-linker), with respectively 4, 20 and 40 mol% cross-linking degree (DAE26-4, DAE26-20, DAE26-40). These resins were employed as acidic components in physical mixtures with Ru/C (5 %, w/w) or as supports for bifunctional ruthenium and copper catalysts, to be used in the hydrogenolysis of glycerol (20 %, w/w, in water). The physical mixtures were more efficient than the bifunctional catalysts, but temperatures as high as 200 °C are required to obtain an appreciable activity. However, in view of their relatively high thermal stability in comparison with the sulfonated polystyrene-divinylbenzene ion-exchange catalysts employed so far they can withstand this temperature, while Amberlyst 70 cannot be employed above 180–190 °C. Interestingly, the catalytic systems based on physical mixtures of DAE with Ru/C resins at 200 °C are much more selective towards propylene glycol than those containing A70 are at 180 °C.     

Gas‐Phase Hydrogenolysis of Glycerol Catalyzed by Cu/MOx Catalysts

The catalytic activities of Cu/MO_x (MO_x = Al₂O₃, TiO₂, and ZnO) catalysts in the gas‐phase hydrogenolysis of glycerol were studied at 180–300 °C under 0.1 MPa of H₂. Cu/MO_x (MO_x = Al₂O₃, TiO₂, and ZnO) catalysts were prepared by the incipient wetness impregnation method. After reduction, CuO species were converted to metallic copper (Cu⁰). Cu/Al₂O₃ catalysts with high acidity, high specific surface areas and small metallic copper size favored the formation of 1,2‐propanediol with a maximum selectivity of 87.9 % at complete conversion of glycerol and a low reaction temperature of 180 °C, and favored the formation of ethylene glycol and monohydric alcohols at high reaction temperature of 300 °C. Cu/TiO₂ and Cu/ZnO catalysts exhibited high catalytic activity toward the formation of hydroxyacetone with a selectivity of approx. 90 % in a wide range of reaction temperature.     

Selective Monolaurin Synthesis through Esterification of Glycerol Using Sulfated Zirconia-Loaded SBA-15 Catalyst

The selective conversion of lauric acid to glycerol monolaurin over sulfated zirconia SBA prepared under various conditions was investigated in this study. The structural properties of the prepared catalysts were characterized using different characterization techniques. Sulfated zirconia was successfully incorporated with improved properties, such as larger mesopore surface area; the mesoporous structure was preserved as well. The highest yield of 79.1% was obtained during reaction over SZSBA-15 catalyst with 16 wt.% zirconium oxychloride loading and 3 h of reflux time. About 83.4% selectivity toward monolaurin was achieved at a high conversion of lauric acid (94.9%), a lauric acid-to-glycerol molar ratio of 4.0, within 6 h, and at 160°C. Product distribution was successfully elucidated. High selectivity to monolaurin was influenced by molecular sieving effects.     

氢解用Pd/C催化剂的工艺研究

优化了氢解用5%Pd/C催化剂的制备工艺,主要讨论了载体预处理、浸渍工艺、还原工艺以及助剂对催化剂活性的影响。研究结果表明:不同载体对催化剂活性的影响很大,以C1为载体,当浸渍液pH值=7,助剂用量为Ni,还原剂为氢气时,制备的催化剂在N-苄基苯胺模型反应中的活性P20为0.200MPa,助剂的使用能够精确控制催化剂的活性。     

Glycerol Hydrogenolysis to 1,2-Propanediol by Cu/ZnO/Al2O3 Catalysts

The effect of preparation methods on the Cu/ZnO/Al₂O₃ catalyst structure and catalytic activity on liquid glycerol hydrogenolysis to 1,2-propanediol has been investigated. The physicochemical properties of the catalysts were characterized by BET, XRD, TG/DTA, NH₃-TPD and TPR. The experimental results showed that the catalyst prepared by an oxalate gel–coprecipitation had the highest activity. At 200 °C and 400 psi hydrogen pressure, the glycerol conversion and 1,2-propanediol selectivity catalyzed by the Cu/ZnO/Al₂O₃ catalyst prepared via oxalate gel–coprecipitation were 92.3 and 94.5 % respectively. It was found that the 1,2-propanediol selectivity was dependent on hydrogen pressure and the un-desired by-products were mainly due to the side reactions caused by the presence of the intermediate acetol.     

Glycerol Hydrogenolysis to 1,2-Propanediol by Cu/ZnO/Al2O3 Catalysts

The effect of preparation methods on the Cu/ZnO/Al₂O₃ catalyst structure and catalytic activity on liquid glycerol hydrogenolysis to 1,2-propanediol has been investigated. The physicochemical properties of the catalysts were characterized by BET, XRD, TG/DTA, NH₃-TPD and TPR. The experimental results showed that the catalyst prepared by an oxalate gel–coprecipitation had the highest activity. At 200 °C and 400 psi hydrogen pressure, the glycerol conversion and 1,2-propanediol selectivity catalyzed by the Cu/ZnO/Al₂O₃ catalyst prepared via oxalate gel–coprecipitation were 92.3 and 94.5 % respectively. It was found that the 1,2-propanediol selectivity was dependent on hydrogen pressure and the un-desired by-products were mainly due to the side reactions caused by the presence of the intermediate acetol.

     

多孔ZSM-5沸石负载Ni2P催化剂对苯乙炔的选择性加氢性能

以酸性多孔ZSM-5沸石(HZSM-5-M)和高比表面积的氧化硅(SiO2)为载体，采用等体积浸渍法制备了负载Ni2P催化剂(Ni2P/HZSM-5-M和Ni2P/SiO2)，对比研究了它们在苯乙炔选择性加氢反应中的催化性能。采用XRD、N2吸附-脱附、NH3-TPD、H2-TPR、SEM和TEM对载体及其负载的Ni2P催化剂进行了表征。催化剂活性结果为：当反应时间为2 h，苯乙炔在Ni2P/HZSM-5-M催化剂的转化率为98.5%，而在Ni2P/SiO2催化剂上仅为45.6%。说明Ni2P/HZSM-5-M催化剂的加氢活性显著高于Ni2P/SiO2催化剂。这是因为，与Ni2P/SiO2催化剂相比，在Ni2P/HZSM-5-M催化剂上形成了小颗粒的Ni2P活性相。同时，Ni2P/HZSM-5-M催化剂的活性具有良好的重复性。     

气相色谱法分析甘油氢解制备丙二醇反应液组成

建立甘油催化氢解制备丙二醇产物的气相色谱定性定量分析方法.该分析方法能够准确地定量分析氢解产物乙醇,1,2-丙二醇,1,3-丙二醇,乙二醇和未反应的甘油,相对标准偏差为1.14％～2.65％,平均回收率在93.05％～103.91％之间,方程的线性相关性良好,是一种简单迅速、准确的分析方法.同时,通过分析数据能够计算反...