TiSiW_(12)O_(40)/TiO_2催化合成苯甲酸戊酯

首次报道了以固载杂多酸盐TiSiW12 O4 0 /TiO2 为多相催化剂 ,对以苯甲酸和正戊醇为原料合成苯甲酸戊酯的反应条件进行了研究 ,实验表明 :TiSiW12 O4 0 /TiO2 是合成苯甲酸戊酯的良好催化剂 ,最佳反应条件为 :醇酸摩尔比为 4∶1,催化剂用量为反应物料总量的 1 5 % ,反应时间为 2 5h。上述条件下 ,苯甲酸戊酯的产率可达 96 7%。     

CO_(2)催化加氢制甲醇技术研究进展

CO_(2)的高效转化利用对缓解能源危机以及实现“碳中和”目标具有重要的战略意义。利用CO_(2)加氢制甲醇是减少碳排放、增加产品价值的一条重要途径。本文从CO_(2)加氢产物,CO_(2)加氢合成甲醇反应机理、催化剂和工艺几个方面论述CO_(2)加氢合成甲醇的研究现状,开发高活性的催化剂是CO_(2)加氢制甲醇实现工业化的关键技术手段。     

高稳定性金红石型TiO_(2)-SiO_(2)载体的制备及表征

采用均匀沉淀法制备金红石TiO_(2)纳米颗粒,再通过溶胶-凝胶法制备一系列不同TiO_(2)含量的金红石型TiO_(2)-SiO_(2)纳米复合物载体,利用比表面积及孔径分析仪、XRD、SEM、FT-IR、UV-vis DRS等对载体结构进行表征,考察TiO_(2)-SiO_(2)载体的高温稳定性。结果表明,TiO_(2)-SiO_(2)载体具有较大的比表面积和典型的SiO_(2)凝胶孔结构,其中的TiO_(2)晶型和晶粒尺寸与纯TiO_(2)相同。高温焙烧后,与纯TiO_(2)发生严重烧结相比,TiO_(2)-SiO_(2)载体表现出优异的高温稳定性,复合材料中的SiO_(2)发生轻微烧结,比表面积和孔容基本不变,其中的TiO_(2)仍保持高分散性,晶粒尺寸不变。TiO_(2)-SiO_(2)载体中未生成Ti-O-Si化学键,而且复合结构对金红石TiO_(2)的能带结构影响较小,TiO_(2)和SiO_(2)只是纳米尺度上的混合,所以SiO_(2)的空间结构是提高TiO_(2)颗粒高温稳定性的主要原因。     

TiSiW_(12)O_(40)/TiO_2催化合成葡萄糖五乙酸酯

介绍了杂多酸 (盐 )型催化剂 Ti Si W1 2 O40 / Ti O2 的制备方法。以自制的Ti Si W1 2 O40 / Ti O2 作为催化剂 ,通过葡萄糖和冰乙酸反应合成了葡萄糖五乙酸酯 ,并探讨了诸因素对产率的影响。实验表明 :Ti Si W1 2 O40 / Ti O2 具有良好的催化活性 ,糖酸摩尔比 1∶ 6 .5 ,催化剂的用量为反应液的 2 .0 % ,酯化反应时间为 2 h,反应温度1 0 2～ 1 0 4℃ ,反应产率可达 89.7%。     

TiSiW_(12)O_(40)/TiO_2催化合成氯乙酸乙酯

首次以固载杂多酸盐TiSiW_(12)O_(40)/TiO_2为多相催化剂,通过氯乙酸和乙醇反应合成了氯乙酸乙酯,并探讨了诸因素对产率的影响。实验表明:TiSiW_(12)O_(40)/TiO_2具有良好的催化活性,醇酸物质的量比为1.4:1,催化剂用量为反应物料总质量的2.0％,反应时间2.0h,反应温度89～96℃,产率可达43.02％。     

固体超强酸TiO_2/SO_4~(2-)催化合成富马酸二甲酯

研究了以ＴｉＯ２／ＳＯ２－４固体超强酸催化富马酸与甲醇合成富马酸二甲酯（ＤＭＦ）的反应,探讨了催化剂制备条件,原料配比,反应时间,催化剂用量等工艺参数对ＤＭＦ收率的影响。在适宜的工艺条件下ＤＭＦ收率达到９０％,催化剂的重复使用实验表明ＴｉＯ２／ＳＯ２－４是ＤＭＦ合成的一个较适宜的催化剂     

含CO2合成气低温合成甲醇的研究

以含CO₂的合成气为原料,Cu-Zn基催化剂,醇溶剂,低温、低压（443 K、3.0 MPa）下合成甲醇。考察了时间、溶剂和催化剂对反应的影响。结果表明,随着反应时间的增加,碳的总转化率、甲醇选择性及收率均逐渐增加;醇溶剂参与反应,但并不被消耗,起到助催化作用,且2-丁醇溶剂表现出较高的反应活性;ZnO、Y₂O₃、La₂O₃、MgO和Al₂O₃作为载体制得的Cu/M_xO_y催化剂,Cu/ZnO呈现出较高的反应活性;稀土元素La作为助剂,能提高Cu-Zn基催化剂的活性,当使用n(Cu)∶n(Zn+La)=1∶1,且n(Zn)∶n(La)=3∶2的Cu/ZnO/La2O3催化剂进行甲醇合成反应时,碳总转化率、甲醇的选择性和收率均高于Cu/ZnO催化剂。     

铜锌铝催化剂的制备及其甲醇重整催化性能研究

以碱式碳酸铜、碳酸镁、碳酸铈、碳酸锰、碳酸铵和水泥-75为原料,以氨水为溶剂,采用新型湿法和共沉淀法制备了铜锌铝催化剂.将相同组分的湿法催化剂和共沉淀法的催化剂在同一条件下进行对比,在气-固相固定床催化反应装置上评价催化剂的甲醇裂解性能.两种制备工艺中,共沉淀法较湿法简单.分析实验数据发现,成分相同时,湿法催化剂的活性...     

Fe~(3 )对TiO_2的自然光催化降解性能影响

采用溶胶—凝胶法制备了TiO2 光催化材料 ,在太阳光的照射下进行了加有Fe3 的染料溶液的光催化降解。实验结果表明 ,加有Fe3 后 ,TiO2 的自然光催化活性显著高于未加Fe3 的染料溶液 ,其与TiO2 在紫外灯下的催化活性相当。并对其催化机理进行了讨论。     

TiSiW_(12)O_(40)/TiO_2在酯合成中的应用

介绍了固载杂多酸盐 TiSiW_(12)O_(40)/TiO_2在催化合成酯(如一元羧酸酯、二元羧酸酯、羟基酸酯、氯乙酸酯、芳香酸酯、葡萄糖酯)中的研究进展。     

Methanol synthesis from CO2-rich syngas over a ZrO2 doped CuZnO catalyst

ZrO₂-doped CuZnO catalyst prepared by successive-precipitation method was investigated by ICP-AES, BET, TEM, XRD, EXAFS, H₂-TPR and CO/CO₂ hydrogenation. The active phase of copper in CuZnO catalyst prepared by co-precipitation method was well-crystallized. The presence of ZrO₂ led to a high copper dispersion, which was distinctive from CuZnO. Though the activity for carbon monoxide hydrogenation was little lower than that of CuZnO catalyst, ZrO₂-doped CuZnO catalyst showed much higher activity and selectivity towards methanol synthesis from carbon dioxide hydrogenation. Moreover, ZrO₂-doped CuZnO catalyst showed high performance for methanol synthesis from CO₂-rich syngas.     

In situ IR studies on the mechanism of methanol synthesis from CO/H2 and CO2/H2 over Cu-ZnO-Al2O3 catalyst

Methanol synthesis from CO/H₂ and CO₂/H₂ was carried out at atmospheric pressure over Cu/ZnO/Al₂O₃ catalyst. The formation and variation of surface species were recorded by in situ FT-IR spectroscopy. The result revealed that both CO and CO₂ can serve as the primary carbon source for methanol synthesis. For CO/H₂ feed gas, only HCOO-Zn was detected; however, for CO₂/H₂, both HCOO-Zn and HCOO-Cu were observed, and without CH₃O-Cu. HCOO-Zn was the key intermediate. A scheme of methanol synthesis and reverse water-gas shift (RGWS) reaction was proposed.     

Performance characteristics of fluidized bed syngas methanation over Ni-Mg/Al2O3 catalyst

The performance characteristics of isothermal fluidized bed syngas methanation for substitute natural gas are investigated over a self-made Ni–Mg/Al2O3 catalyst. Via atmospheric methanation in a laboratory fluidized bed reactor it was clarified that the CO conversion varied in 5% when changing the space velocity in 40–120 L·g?1·h?1 but the conversion increased obviously by raising the superficial gas velocity from 4 to 12.4 cm·s?1. The temperature at 823 K is suitable for syngas methanation while obvious deposition of uneasy-oxidizing Cγoccurs on the catalyst at temperatures around 873 K. From a kinetic aspect, the lowest reaction temperature is suggested to be 750 K when the space velocity is 60 L·g?1·h?1. Raising the H2/CO ratio of the syngas increased proportionally the CO conversion and CH4 selectivity, showing that at enough high H2/CO ratios the active sites on the catalyst are sufficient for CO adsorption and in turn the reaction with H2 for forming CH4. Introducing CO2 into the syngas feed suppresses the water gas shift and Boudouard reactions and thus increased H2 consumption. The ratio of CO2/CO in syngas should be better below 0.52 because varying the ratio from 0.52 to 0.92 resulted in negligible increases in the H2 conversion and CH4 selectivity but decreased the CH4 yield. Introducing steam into the feed gas affected little the CO conversion but decreased the selectivity to CH4. The tested Ni–Mg/Al2O3 catalyst manifested good stability in structure and activity even in syngas containing water vapor.     

TiSiW_(12)O_(40)/TiO_2催化合成丙酸异丁酯

以TiSiW12O40/TiO2为催化剂,对以丙酸和异丁醇为原料合成丙酸异丁酯的反应条件进行了研究。实验表明:TiSiW12O40/TiO2是合成丙酸异丁酯的良好催化剂,适宜的反应条件为:醇∶酸(摩尔比)=1.2∶1,催化剂用量为反应物料总质量的2.0%,反应时间1.0h,反应温度106～125℃。上述条件下,丙酸异丁酯的收率可达79.1%。     

Ag掺杂V2O5/TiO2催化氧化3-甲基吡啶 脱甲基效应

浸渍法制备了不同Ag掺杂的Ag-V/TiO2催化剂,考察其催化部分氧化3-甲基吡啶脱甲基性能。采用X射线衍射（XRD）,X射线光电子能谱（XPS）,H2程序升温还原（H2-TPR）对催化剂进行了表征。表征表明,Ag的掺杂提高催化剂中表面氧和 4价态的钒物种的含量,有效的加快了催化剂的还原过程,提高了氧化活性。3-甲基吡啶氧化反应表明,Ag掺杂使反应选择性发生根本性变化,主产物由烟酸变成吡啶,选择性84.7%,烟酸几乎不产生。该脱甲基氧化反应的过程是V4 /V5 （O2-）在攻击侧链的C-H键的同时Ag在O2的作用下形成了含有亲电子型氧（O-和O2-）的Agp O活性物种,攻击侧链和苯环相连的C-C键,Ag和V共同作用将侧链的甲基以氧化形成COx的形式脱除。     

Methanol synthesis over a Zn-deposited copper model catalyst

Methanol synthesis by the hydrogenation of CO₂ over Zn-deposited polycrystalline Cu was studied using surface science techniques. The Zn sub-monolayer was oxidized by the reaction mixture during the reaction at 523 K, leading to the formation of ZnO species. The kinetic results definitely showed that the ZnO species on the Cu surface promoted the catalytic activity of methanol formation, where the activity of Cu increased by a factor of 6 at the Zn coverage of 0.17. A volcano-shaped curve was obtained for the correlation between the Zn coverage and the catalytic activity, which was very similar to the correlation curve between the oxygen coverage and the specific activity for methanol formation previously obtained for the Cu powder catalysts. The role of ZnO in Cu/ZnO based catalysts was ascribed to the stabilization of Cu⁺ species by the ZnO moieties on the Cu surface.     

Au-Ru/TiO2催化硝基苯和苯甲醛一锅法合成N-苄基苯胺

采用沉积-沉淀法制备出一系列Au-Ru/TiO2双金属催化剂,用于硝基苯与苯甲醛一锅法加氢反应合成N-苄基苯胺。考察了Ru负载量对Au-Ru/TiO2加氢性能的影响,并采用X射线衍射和扫描电镜等方法对催化剂进行表征。结果表明,Au和Ru产生协同作用共同促进加氢作用。负载Ru质量分数为1.5%的催化剂具有最好的加氢活性和N-苄基苯胺选择性。优化的N-苄基苯胺合成工艺条件为：催化剂用量占硝基苯质量的15%,溶剂为甲苯,氢压1.1 MPa,反应温度80 ℃。此条件下,硝基苯转化率100%,N-苄基苯胺选择性88.2%     

溶胶-凝胶法制备掺杂型V2O5/TiO2脱硝催化剂

以十二胺表面活性剂为模板剂,钛酸四丁脂为无机母体源,采用溶胶-凝胶法制得稳定的TiO₂凝胶,经焙烧得到掺杂型V₂O₅/TiO₂脱硝催化剂粉末。分别用热重分析、X射线衍射、拉曼光谱和氮气吸附脱附法对催化剂进行了结构、比表面积和孔径的表征。在固定反应床,对氮氧化物的脱除活性进行了考察。结果表明,催化剂为锐钛矿,呈介孔结构,比表面积为118.5 m^₂·g^_-1,孔径（6～8） nm。钒以V=O键形式单层分布于TiO₂中。催化活性评价结果表明,制备的催化剂在空速10 000 h^-1和温度（180～450） ℃有较好的催化活性,空速对催化活性的影响主要在270 ℃以下。