Preparation of Organo-Functionalized Mesoporous Zeolites Supported Phosphine-Rhodium Complex and Their Catalytic Performance for Hexene-1 Hydroformylation

制备了表面有机官能团化的MCM 4 1和MCM 4 8介孔分子筛以及SiO2 等载体固载铑膦配合物催化剂 ,考察了所制备催化剂对液相己烯 1氢甲酰化的催化性能 ,并用X射线衍射、BET、红外光谱和原子吸收光谱等技术对载体和催化剂的组成和结构进行了表征 .结果表明 ,固载化铑膦配合物对烯烃氢甲酰化的催化性能与有机官能团的种类及载体的结构有关 ;固载于含胺基和腈基有机官能团化介孔分子筛载体的铑膦配合物表现出较高的催化活性和稳定性 .Organo-functionalized mesoporous zeolites MCM-41 and MCM-48, and amorphous SiO 2 were used as supports to prepare heterogenized phosphine-rhodium complex via anchoring for the hydrofomylation of hexene-1. The supports and the catalysts were characterized by means of XRD, BET, FT-IR and AAS. The MCM-41 and MCM-48 were functionalized with silanes containing (mono-, di-, tri-) amino-, mercapto- and nitrile- groups, respectively, without destruction of the mesoporous structure of the zeolites. The catalytic performance of the catalysts was related to the structure of organo-groups and also to the structural features of the supports. Higher catalytic activity and selectivity for n-C 6H 13CHO were obtained in the case of the catalysts using the mesoporous zeolites functionalized with amino- and nitrile-silanes as supports. No significant decrease in the catalytic performance of the phosphine-rhodium complex immobilized on the amino-functionalized mesoporous zeolites used repeatedly for 6 times was observed.国家自然科学基金 (2 0 0 2 3 0 0 1,2 0 0 2 10 0 2 );; 国家重点基础研究发展规划 (G2 0 0 0 0 480 0 8)资助项

Liquid Phase Selective Oxidation of Toluene and Ethylbenzene over V-based Catalysts in the Presence of Hydrogen Peroxide

研究了若干钒基催化剂在双氧水存在下对甲、乙苯的液相选择性氧化催化性能 .结果表明 :在乙腈为溶剂的反应体系中 ,所研究的钒基催化剂包括VPO ,VOPO4,V2 O5,VO(acac) 2 和NH4VO3 等均表现出以苯甲醛为甲苯选择性氧化主产物和以苯乙酮为乙苯选择氧化主产物的反应结果 ;从反应活性和主产物选择性来看 ,按以下顺序递减 :VPO >V2 O5>VOPO4>VO(acac) 2 >NH4VO3 .对于具有 (VO) 2 P2 O7晶相的VPO催化剂 ,在双氧水存在下对甲苯选择性氧化主产物苯甲醛的最高选择性为 5 8 8% ,乙苯选择性氧化主产物苯乙酮的最高选择性为 67 8% ;其催化性能与P/V比、焙烧条件、双氧水的使用量、反应溶剂等有关 .从已有的实验结果推测 ,钒基催化剂在双氧水存在下的甲、乙苯选择氧化反应与V5+ /V4+ 的“氧化 -还原”作用密切相关 .The selective oxidations of toluene and ethylbenzene using hydrogen peroxide over vanadium-based catalysts such as VPO, VOPO 4, V 2O 5, VO(acac) 2 and NH 4VO 3 have been studied. These catalysts were found to be active for the oxidation of toluene and ethylbenzene to benzaldehyde and acetophenone as main products in acetonitrile solvent, respectively. The activity and selectivity, however, in a sequence of decrease order, was found to be followed as: VPO>V 2O 5>VOPO 4>VO(acac) 2>NH 4VO 3. The highest selectivities to benzaldehyde from toluene and acetophenone from ethylbenzene were 58 8% and 66 1% over VPO catalyst with P/V=1 1 (molar ratio) in acetonitrile solvent, resepectively. The catalytic performance of VPO with (VO) 2P 2O 7 phase was affected by the molar ratio of P/V, hydrogen peroxide amount, solvent property and temperature. The active center for the oxidation was believed to be (VO) 2P 2O 7 sites (V 4+) in combination with dynamic V 5+ sites involving a reversible redox cycle.国家自然科学基金 (No.2 0 0 2 1 0 0 2 )资助项

Effect of Ti-Si mixed oxide support on gold catalysts for gas-phase epoxidation of propylene

Titania-silica mixed oxides prepared by hydrolytic and one-step non-hydrolytic sol-gel routes using TICl4 and SiCl4 as precursors were employed as the gold catalyst supports for gas-phase epoxiclation of propylene in O-2 and H-2. Characterization studies of the supports and catalysts were performed by means of X-ray diffraction, ultraviolet-visible absorption spectroscopy, N-2 adsorption, and high-resolution transmission electron microscopy. The results indicated that the amorphous Ti-Si mixed oxides containing 6%-14% of Ti could be prepared by both sol-gel routes, but those by non-hydrolytic sol-gel afforded higher surface area and significant mesopores. A superior catalytic performance was obtained with the gold catalyst supported on the non-hydrolytic sol-gel Ti-Si mixed oxide containing 10% of Ti. The propylene conversion was 5.7% at the initial 60 min and 3.3% at 240 min of time on stream. The selectivity for propylene oxide was as high as 95%. The influences of aging time for the non-hydrolytic sol-gel and pH value for the Au deposition-precipitation on the performance of the Au catalyst were also discussed

Effect of Ti-Si Mixed Oxide Support on Gold Catalysts for Gas-Phase Epoxidation of Propylene

以TiCl4和SiCl4为原料,采用水解和非水水解溶胶-凝胶两种方法制备了一系列不同Ti含量的Ti-Si复氧化物载体,继而用沉积-沉淀法制得载金催化剂.采用X射线衍射、紫外-可见漫反射光谱、N2吸附和高分辨透射电镜对催化剂进行了表征,并考察了催化剂在氢气和氧气存在下的丙烯气相环氧化催化性能.研究表明,钛含量在6%~14%范围内时,两种方法制得的Ti-Si复氧化物均为无定形结构,但采用非水水解溶胶-凝胶法制得的载体比表面积较高.以非水水解溶胶-凝胶法制备的钛含量10%的Ti-Si复氧化物为载体得到的载金催化剂表现出较高的活性和选择性,反应60min时,丙烯转化率为5.7%,240min后降为3.3%,环氧丙烷的选择性稳定于95%左右.还考察了非水水解溶胶-凝胶的陈化时间和金沉积-沉淀溶液的pH值等对反应结果的影响.Titania-silica mixed oxides prepared by hydrolytic and one-step non-hydrolytic sol-gel routes using TiCl_4 and SiCl_4 as precursors were employed as the gold catalyst supports for gas-phase epoxidation of propylene in O_2 and H_2. Characterization studies of the supports and catalysts were performed by means of X-ray diffraction, ultraviolet-visible absorption spectroscopy, N_2 adsorption, and high-resolution transmission electron microscopy. The results indicated that the amorphous Ti-Si mixed oxides containing 6%-14% of Ti could be prepared by both sol-gel routes, but those by non-hydrolytic sol-gel afforded higher surface area and significant mesopores. A superior catalytic performance was obtained with the gold catalyst supported on the non-hydrolytic sol-gel Ti-Si mixed oxide containing 10% of Ti. The propylene conversion was 5.7% at the initial 60 min and 3.3% at 240 min of time on stream. The selectivity for propylene oxide was as high as 95%. The influences of aging time for the non-hydrolytic sol-gel and pH value for the Au deposition-precipitation on the performance of the Au catalyst were also discussed.国家自然科学基金(20021002,20473065,20433030);; 福建省科技重大专项(2005HZ01-3)资助项目

Advances for the Ruthenium Complexes-Based Homogeneous Catalytic Hydrogenation of Oxalates to Ethylene Glycol

草酸酯加氢是重要的有机化学反应,在工业制乙二醇生产中有着重要的应用.对钌金属配合物均相催化反应的研究进行了综述.以催化反应体系为焦点,探讨了多种; 因素如温度、氢气压力、催化剂浓度、反应时间、添加剂等对底物转化率以及产物选择性的影响,并讨论了催化反应机理,其中金属-配体协同促进的H_2分子异; 裂,进而完成对底物分子中酯基依次加氢的反应机理是探讨的重点,这为新型催化剂的设计和应用提供参考.Hydrogenation of oxalates is one of the important organic reactions, which has an ultimate use for the industrial production of ethylene glycol. The studies on the ruthenium complexes-based homogeneous catalytic reaction systems are herein summarized. With the focus on the catalytic reaction systems, the important factors with significant influences on the oxalate transformation efficiency as well as the product selectivity are discussed, including temperature, H-2 pressure, catalyst concentration, reaction duration, additives, and so on. The catalytic reaction mechanisms are also discussed in detail, where the mechanism for the H-2-heterolysis promoted under the metal-ligand cooperation for the oxalate hydrogenation to ethylene glycol is enhanced. This study would be useful for designing the new catalyst applicable in industry.National Natural Science Foundation of China [21473142, 91545115,; 21473145]; Innovative Research Team of China [IRT_14R31, J1310024

水溶性铑膦配合物HRh(CO)(TPPTS)_3及其相关体系的--1H-NMR研究

在液体高分辨nMr谱仪上， 测定并比较了具有高效烯烃氢甲酰化活性的水溶性铑膦配合物HrH（CO）（TPPTS）3 及与此有关的配体TPPTS和OTPPTS分别在d2O、混合溶剂d2O-THf（d8）-Cd3Od中的1H-nMr谱图， 并借助1H-1H COSy谱对上述3 种化合物的1H-nMr谱峰进行了指认； 讨论了影响化学位移和偶合常数的因素， 为水溶性铑膦配合物催化剂的结构与催化性能的关联及新催化剂设计研究提供了基础数据.国家自然科学基金;教育部优秀年轻教师基

Direct immobilization of phosphine-rhodium complex on MCM-41 for propene hydroformylation

MCM-41 molecular sieve supported Rh-PPh3 catalysts were prepared by the in-situ assembling of the metal complex from smaller moieties of Rh(acac) (CO)(2) and ligand of PPh3. The resulted guest/host materials (Rh-PPh3/MCM-41) were characterized by X-ray powder diffraction, FTIR and P-31 (H-1.) NMR, and served as catalysts for propene hydroformylation. The results showed negligible change in MCM-41 framework after propene hydroformylation at 393 K. Higher hydroformylation activities were obtained on Rh-PPh3/MCM-41 catalysts compared to that on Rh-PPh3/SiO2,

Selective Oxidation of Methane to Methanol in Oleum over Pd/C Catalyst

以PdCl2为前驱体,采用浸渍法制备了Pd/C催化剂,并在发烟硫酸中考察了其催化甲烷选择氧化反应的性能,采用X射线粉末衍射、X射线光电子能谱、高分辨透射电镜和CO吸附等方法对催化剂进行了表征.甲烷选择氧化反应得到的主产物硫酸单甲酯经水解后得到甲醇,在5%Pd/C催化剂、Pd用量30μmol、反应温度180℃、反应压力4.0 MPa、反应时间4 h和发烟硫酸中SO3含量为50%的优化工艺条件下,甲烷转化率为23.6%,甲醇的选择性和收率分别为69.5%和16.4%,在一定程度上可实现催化剂的多次重复使用.Pd/C催化剂上的甲烷选择氧化反应可能遵循亲电取代机理,催化性能与Pd负载量、Pd粒子尺寸和分散度等有关.The selective oxidation of methane to methanol over Pd/C catalysts generated from a PdCl2 precursor was investigated in oleum.Characterization of the catalysts was performed by X-ray diffraction,X-ray photoelectron spectroscopy,high-resolution transmission electron microscopy,and CO adsorption.The major product in the oxidation reaction was methyl bisulfate,which was then hydrolyzed into methanol.Methane conversion of 23.6% with methanol selectivity of 69.5% and yield of 16.4% was achieved under the optimum conditions of 5%Pd/C,30 μmol Pd,reaction temperature 180 ℃,methane pressure 4.0 MPa,reaction time 4 h,and 50% sulfur trioxide concentration.After facile separation with the reactants and pretreatment,the catalyst could be reused several times with considerable stability.The selective oxidation of methane catalyzed by Pd/C catalysts in oleum possibly involved an electrophilic substitute mechanism.The catalytic performance was related to the Pd loading,dispersion,and particle size.国家自然科学基金(20473065);; 福建省科技重大专项(2005HZ01-3

利用本科生科研训练平台培养高素质人才

通讯联系人, Em ai:l yax ian@ xmu. edu. cn厦门大学化学人才培养基地十分重视本科生科研训练,依托化学学科优势,从2003年起设立了"化学人才基地育苗基金",制定了一系列政策鼓励学生进入科研课题组,通过科研训练发展个性、培养创新能力、提高综合素质,建立了一个较完善的本科生科研训练平台。国家基础科学人才培养基

丙烯氢甲酰化HRh(CO)(PPh_3)_3/SiO_2催化剂的NMR研究

用固定床加压气相连续流动微反－气相色谱组合装置评价了ＳｉＯ２负载铑膦配合物催化剂上丙烯氢甲酰化反应．通过溶液（或液膜）３１Ｐ（１Ｈ）ＮＭＲ谱表征，发现配合物ＨＲｈ（ＣＯ）（ＰＰｈ３）３负载于硅胶载体上之后，原负载前驱苯溶液３１Ｐ（１Ｈ）ＮＭＲ谱在４１．１ｐｐｍ处的特征峰消失，但在化学位移为３７．０ｐｐｍ附近出现一新的宽峰，后者可能缘于配合物与载体表面发生相互作用．反应４ｈ后工作态催化剂的ＮＭＲ测试表明，在丙烯氢甲酰化反应条件下，铑的三膦配合物发生部分解络；工作态催化剂表面上主要的铑膦催化活性物种是含双膦的配合物物种，并暗示存在着含双羰基或羰、酰基的反应中间态；同时也观察到可归属于解络后的游离三苯基膦物种的相应谱峰．反应９０ｈ后催化剂的ＮＭＲ谱显示，铑配合物催化剂中膦配体含量已相当低；反应过程中膦配位体被氧化及铑、磷组份的流失是负载型催化剂活性下降乃至失活的主要原因