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对羟基苯甲酸乙酯合成新法 总被引:6,自引:0,他引:6
研究用固体超强酸SO2-4/TiO2代替硫酸作催化剂、3A或4A分子筛作脱水剂合成对羟基苯甲酸乙酯的工艺,讨论了催化酯化的各种影响因素,确定了最佳工艺条件 相似文献
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将强酸中心SO4^2--Fe2O3引入膨润土表面,制备出具有增强酸性的SO4^2--Fe2O3/膨润土固体酸催化剂,并用于苯酐和正丁醇的酯化反应。讨论不同氧化物改性、硫酸浓度、PH值、酐醇比及焙烧温度等对合成DBP反应的影响,并用Hammett指示剂正丁胺滴定法定量表征了催化剂表面的总酸度和酸强度分布。 相似文献
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沉淀剂的不同对固体超强酸SO^2—4/TiO2—NiO性能的影响 总被引:2,自引:0,他引:2
通过对固体超强酸的比表面测定,差热分析及催化酯化性能考察,研究了不同沉淀剂对固体超强酸SO^2-4/TiO2-NiO催化剂在物性和催化性的影响,认为尿素作沉淀剂可增强TiO2与NiO2之间相互作用,抑制Ni离子和SO^2-4生成盐,氨水作为沉淀剂则不能促使TiO2与NiO的强相经作用 相似文献
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L—半胱氨酸希夫碱及其铜,锌配合物的合成及表征 总被引:1,自引:0,他引:1
报道了由L-半胱氨酸与2,4-二羟基苯甲醛合成希夫碱N-2,4-二羟基苯甲醛-L-半胱氨酸(简称SCYS),并与过渡金属Cu(Ⅱ)、Zn(Ⅱ)形成配合物(简称SCYS-Cu、SCYS-Zn)。对所合成的化合物进行了组成及结构分析。结果表明,SCYS为NOS型三齿配体,配合物为四配位化合物。 相似文献
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分子筛在甲胺磷异构化反应中的应用 总被引:1,自引:0,他引:1
本文对几种类型的沸石分子筛在O,O-二在硫代磷酰胺异构化生成O,S--二甲基硫代磷酰胺中应用为助催化剂进行了研究,结果表明:A型沸石分子筛具有较好的助催化作用,比不加助催化剂的情况O,S-二甲基硫代磷酰胺含量和收率均提高5%左右。 相似文献
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SO_4~(2-)/TiO_2-Al_2O_3复合固体超强酸的结构表征 总被引:2,自引:0,他引:2
用Hammett指示剂、NH3-TPD、FT-IR、TG-DTA、XRD及SEM等分析手段对催化剂SO42-/TiO2-A12O3的结构进行了研究,结果表明:该催化剂为固体超强酸,其表面酸强度与焙烧温度有很好的对应关系;催化剂表面存在SO42-;催化剂的热稳定性较好,说明SO42-与金属氧化物之间的化学键较为牢固;催化剂经多次使用后主体结构未发生变化,有较长的使用寿命和良好的再生性能;催化剂的表面呈疏松状结构,具有很高的催化活性。 相似文献
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固体超强酸催化合成对羟基苯甲酸乙酯的研究 总被引:27,自引:0,他引:27
以固体超强酸SO42-/TiO2为催化剂,4A分子筛作脱水剂,合成了对羟基苯甲酸乙酯。应用该方法,酯化反应产率高达84%,同时对影响产率的诸因素进行了考察,其最佳反应条件为:醇酸摩尔比4∶1,催化剂用量9%,反应时间3h,反应温度115~135℃。 相似文献
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无机氟改性的HZSM—5分子筛催化1,2,4—三甲苯与甲醇烷基化合成… 总被引:1,自引:0,他引:1
用不同浓试的NH4F对HZSM-5分子筛进行改性制成偏三甲苯-甲醇烷基化反应的催化剂,考察反应时间、改性剂浓度、焙烧温度对其催化性能的影响。结果发现,无机氟改性使HZSM-5分子筛对偏三甲苯-甲醇烷基化合成均四甲苯反应的活性、选择性及催化剂的稳定性都有良好的促进作用,并且改性后的HZSM-5分子筛加入结合剂制成的催化剂仍具有良好的催化性能。采用SEM、IR及TPD等方法测试无机氟改性后HZSM-5 相似文献
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采用等体积浸渍法对Y分子筛进行了Zr修饰改性,系统考察了不同用量Zr对改性Y分子筛的结构、催化剂的理化性质和加氢裂化反应性能的影响规律。通过XRD、NH3-TPD、H2-TPR和TEM等方法对改性分子筛和催化剂进行表征分析。结果表明:Zr改性降低了Y分子筛的酸量,随着改性Zr用量的增加,这种变化趋势不断增大。同时,Zr改性有效地削弱了分子筛催化剂中金属活性组分与载体间的作用,提高了W物种在催化剂表面的分散程度。加氢裂化反应结果表明:与Y分子筛催化剂相比,Zr改性Y分子筛催化剂的减压馏分油(VGO)转化率降低,中间馏分油选择性提高约20%,随着改性Zr用量的增加,VGO的转化率不断降低,中间馏分油选择性略有增加。 相似文献
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以4种不同硅铝比的Y型分子筛作为吸附剂,在间歇式反应釜中对含喹啉的十二烷溶液进行静态吸附脱氮实验,考察分子筛的吸附脱氮性能;用不同浓度的草酸对Y分子筛进行改性,并进行吸附脱氮性能考察。结果表明,随着硅铝比的增加,Y型分子筛的总酸量和强酸量减少,弱酸量增加,脱氮率由50.43%降到37.32%;当草酸处理浓度为40%时,改性分子筛具有最高的脱氮率为57.83%。 相似文献
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Pier Parpot Catarina Teixeira António M. Almeida Cristina Ribeiro Isabel C. Neves António M. Fonseca 《Microporous and mesoporous materials》2009,117(1-2):297-303
The electroactivity of zeolite-encapsulated redox-active transition metal complexes was explored for copper(II)-PAN (PAN = 1-(2-pyridylazo)-2-naphthol) complex encaged in the supercages of Y zeolite. Copper(II)-PAN complex and the zeolite boundary were investigated electrochemically by dispersion with a Nafion/water solution on carbon Toray as supporting electrode. Encapsulation was achieved by: (i) ion exchange of copper(II) in NaY zeolite and (ii) coordination of the intrazeolite metal ion with the PAN ligand using an L:copper(II) molar ratio of 2:1. The resulting materials were characterized by cyclic voltammetry in zeolite modified electrodes, surface analysis (XPS, SEM and XRD), spectroscopic methods (EPR and FTIR) and chemical analysis, which indicated that the copper(II)-PAN complex was effectively encapsulated inside the supercages of NaY, without any modification of the morphology and structure of the zeolite. The coordination geometry of Y-encapsulated copper(II)-PAN complex has been obtained with preferentially 1:1 stoichiometry analogous to the model complex, [CuCl(PAN)], by molecular simulations. For the cyclic voltammetry studies, the electrochemical behavior of free complex was compared with copper(II)-PAN complex encapsulated in Y zeolite. The results show evidence for electroactivity restricted to the boundary associated to the copper(II)-PAN complex. 相似文献
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改性分子筛催化乳酸甲酯的脱水反应 总被引:2,自引:0,他引:2
通过生物基路线制备丙烯酸及酯具有潜在的经济效益.同时对化石资源的绿色替代具有重要意义.考察了X.Y.ZSM-5等沸石分子筛经过钾、钙、钻等金属离子交换改性后,在乳酸甲酯脱水制备生物基丙烯酸甲酯过程中的催化性能.试验结果表明K离子改性Y沸石分子筛对产物的选择性高,而ZSM-5类具有较高的转化率,但是选择性低.分析结果说明:Y分子筛催化剂的高选择性与其特有的骨架结构相关.沸石分子筛催化剂需要通过金属离子的交换才能调整到适当的酸碱性实现最佳催化的效果.在上述结论的基础上.以钾离子改性的NaY分子筛为催化剂,对反应温度.反应空适等反应条件进行了优化得到了较高的丙烯酸甲酯得率. 相似文献
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Xuejun Zhang Fuqiang Zhang Xuewu Yan Zhihua Zhang Famin Sun Zongxian Wang Dongyuan Zhao 《Journal of Porous Materials》2008,15(2):145-150
A series of Y/Al-SBA-15 composites were prepared by a two-step synthesis procedure in mild acidic medium. The materials were
characterized by powder X-ray diffraction (XRD), N2 sorption isotherms and TEM techniques. Catalytic cracking of cumene and 1,3,5-tri-isopropylbenzene was carried out as the
probing reactions on these composites. The XRD results showed that these materials are composites of Al-SBA-15 and Y zeolite.
N2 sorption isotherms and TEM displayed that these composites were abundant in micropores and mesopores. At the same time, the
mesopores may communicate with the␣micropores in some domains, which may result in the high catalytic activities of Y/Al-SBA-15
composites for the␣cracking of both small-molecule (cumene) and large-molecule (1,3,5-tri-isopropylbenzene) hydrocarbons.
The existence of mesopores may also make the acid sites easily accessible for reactants. Catalysts of W–Ni supported on Y/Al-SBA-15
and modified Y zeolites with mesopores were prepared by impregnation method, and the hydrocracking of heavy oil was performed
on these catalysts. The catalyst using zeolite Y/mesoporous Al-SBA-15 composites as support gave higher yield of diesel compared
to the catalysts using modified zeolite Y as support. In addition, the higher aromatics potential of heavy naphtha and the
significantly lower BMCI (U.S. Bureau of Correlation Index) of tail oil revealed Y/Al-SBA-15 composite catalyst possessed
integrated performance in the hydrocracking of heavy oil. These results proved that the combination of Y zeolites and mesoporous
Al-SBA-15 plays a great role in improving the performance of catalysts for hydrocracking heavy oils. 相似文献