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排序方式: 共有103条查询结果,搜索用时 281 毫秒
1.
TiO2作为重要的功能性环保无机材料, 因具有特殊的光电性质和物化性能而广泛应用于介(压)电材料、涂料及催化等领域[1~3]. 戊二醛(Glutaraldehyde)是一种重要的精细化学品, 但其生产工艺复杂、条件苛刻. 邓景发等[4]成功开发了以环戊烯为原料, 双氧水为氧化剂, 均相钨酸为催化剂的新型一步法合成路线, 工艺操作简单, 降低了生产成本. 但由于均相催化剂分离复杂, 其固载化方法正在研究中[5~7]. 本文以TiCl4为前驱体, 在均相醇-水热体系中首次合成了高比表面积和规整中孔结构的TiO2微球(约3.6 μm), 其外壳约100 nm, 空隙壳层约300 nm. 考察了制备条件对TiO2微球结构的影响, 并采用孔分布, XRD, SEM及TEM等手段对该TiO2微球进行了表征, 同时考察了TiO2微球负载的WO3催化剂在环戊烯催化氧化合成戊二醛中的反应行为, 并与其它载体进行了比较. 相似文献
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Studies on ring-opening polymerization of chloromethyl thiirane with rare earth catalysts and functional resins synthesized therewith were reviewed. 相似文献
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Based on infrared absorption spectroscopy technique, a carbon monoxide sensor was developed using the fundamental absorption band of carbon monoxide molecule at the wavelength around 4.6 µm. The developed sensor consists of pulse-modulated wideband incandescence, open ellipsoid light-collector gas-cell, dual-channel detector, and control and signal-processing module. With the prepared standard carbon monoxide gas sample, sensing characteristics on carbon monoxide were investigated using the sensor. Experimental results reveal that the limit of detection is about 10 ppm, the relative error at the limit of detection point is less than 14%, and that is less than 7.8% within the low concentration range of 20~180 ppm. The maximum absolute errors of 50 min long-term measurement on the 0 and 14 ppm CO gas samples are about 3 and 3.17 ppm, respectively, and the standard deviations are as small as 0.18 and 1.25 ppm, respectively. Compared with the reported carbon monoxide detection systems utilizing quantum cascaded lasers and distributed feedback lasers, the proposed sensor shows potential applications in carbon monoxide detection under the circumstances of coal-mine and environmental protection, by virtue of high performance, low cost, simple optical structure, and so on. 相似文献
5.
CuCl has been successfully immobilized on a novel diamide modified SBA-15, and proven to be an efficient heterogenized catalyst for the oxidative carbonylation of methanol to dimethylcarbonate. 相似文献
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Employing the ionothermal synthesis approach, three new transition-metal-containing polyoxotungstate hybrids: [Dmim]2Na3[SiW11O39Fe(H2O)]·H2O (Dmim=1,3-Dimethylimidazole) (1), [Emim]9Na8[(SiW9O34)3{Fe3(μ2-OH)2(μ3-O)}3(WO4)]·0.5H2O(Emim=1-Ethyl-3-meth-ylimidazole) (2) and [Dmim]2[HMim]Na6[(AsW9O33)2{MnIII(H2O)}3]·3H2O (Dmim=1,3-Dimethylimidazole; Mim=1-Methylimidazole) (3) have been synthesized in 1-ethyl-3-methyl imidazolium bromide ([Emim]Br) ionic liquids (ILs). Compound 1 possesses a 3-D open framework constructed from the mono-ironIII-substituted α-Keggin-type anion and the organic cations [Dmim]+ through the hydrogen bond interactions. Compound 2 contains a [{FeIII3(μ2-OH)2(μ3-O)}3(μ4-WO4)] cluster surrounded by three [SiW9O34]10− ligands, eight sodium cations and nine dissociative [Emim]+ cations around the polyoxoanion. The polyoxoanion of 3 consists of a high-valent trinuclear-manganese (III)-substituted sandwiching polyoxoanion based on the [α-AsW9O33]9− units. All the compounds are characterized by elemental analyses, IR, UV-vis spectra, TG-DTA and XRD analyses. The XPS and EPR spectra of MnIII in 3 were studied. The photocatalytic and electrocatalytic properties, as well as the stabilities of 1-3 were also investigated. 相似文献
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Cu/SiO2 catalysts with different bimodal pore structures adjusted by the ratio of HMS and silica sol were prepared via modified impregnation method. Structure evolutions of the catalyst were systematically characterized by N2-physisorption, X-ray diffraction, H2 temperature-programmed reduction, N2O titration and X-ray photoelectron spectroscopy. The results show that the composite silica supported copper catalysts showed remarkably enhanced catalytic performance in the selective hydrogenation of dimethyl oxalate to ethylene glycol compared to the individual silica supported ones obtained by the same method. The dimethyl oxalate conversion and the ethylene glycol selectivity can reach 100% and 98% at 473 K with 2.5 MPa H2 pressure and 1.5 h−1 liquid hour space velocity of dimethyl oxalate over the optimized Cu/SiO2 catalyst. The remarkably enhanced catalytic performance of Cu/SiO2 catalysts might be attributed to the homogeneous dispersion and uniformity of the active copper species and to the larger copper surface areas attained on the HMS supports with large pore diameters and surface areas. 相似文献
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