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分别采用不同的季铵盐四丁基氯化铵(Bu4NCl)、三辛基甲基氯化铵(C8H17)3CH3NCl和溴化十六烷基吡啶(π-C5H5NC16H33Br)与钨酸或钨酸钠、磷钨酸反应制得过氧化磷钨杂多酸季铵盐Q 3{PO4[W(O)O4]3[W(O)O4]}3-(Q :季铵盐正离子R4N ),以其为催化剂、二氯乙烷为溶剂、H2O2为氧化剂氧化苯乙烯,结果发现过氧化磷钨三辛基甲基铵有很好的催化活性,在反应温度55℃、pH=3.0、n(催化剂)∶n(苯乙烯)∶n(H2O2)=1∶100∶120时,苯乙烯的转化率为40.2%,环氧苯乙烷的选择性为39.2%. 相似文献
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磷钼杂多酸季铵盐催化氧化合成苯甲酸 总被引:2,自引:0,他引:2
采用四丁基溴化铵和磷钼酸反应合成了一系列Keggin型磷钼酸季铵盐催化剂,傅立叶红外光谱分析表明,所制备的催化剂具有典型的杂多阴离子结构.将其应用于冰乙酸作溶剂、30%过氧化氢作氧化剂催化氧化苯甲醛制苯甲酸的反应过程中,详细考察了反应条件对反应的影响.结果表明,催化剂中各组分在双氧水作用下催化活性较高,任一组分单独作用时催化活性较低,只有当催化剂中季铵盐与磷钼酸配比合适时,催化效果才会最优,其中[(C4H9)4N]H2PMo12O40的催化活性最优.在最佳合成条件下,即苯甲醛20 mmol、30%双氧水60 mmol、催化剂0.07 mmol、冰乙酸8 mL、反应温度75℃、反应时间6 h,苯甲酸收率达87.82%,且催化剂重复使用情况良好. 相似文献
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若干磷钼酸季铵盐的合成及其催化H2O2反应性能研究 总被引:1,自引:0,他引:1
以Keggin型杂多酸——磷钼酸(H3PMo12O40)酸根为阴离子,以具有不同有效碳原子数的季铵盐为反荷阳离子,合成出了一系列磷钼酸季铵盐,并用元素分析、红外光谱等技术进行了表征,检测结果表明所合成的磷钼酸季铵盐酸根部分均保持Keggin型磷钼酸结构特点,且具有Q3PMo12O40结构。以Q3PMo12O40为催化剂,Mo(Ⅵ)为催化活性组分,用于催化过氧化氢分解反应,考察了不同结构的磷钼酸季铵盐对催化过氧化氢分解反应活性的影响,结果表明所合成的Q3PMo12O40催化分解过氧化氢反应表观皆为一级反应,Q^ 中有效碳原子数在16~19间催化活性较好。此外,将不同活性的杂多酸盐用于催化过氧化氢环氧化环己烯反应,结果发现其催化环氧化活性与分解过氧化氢活性顺序具有可类比性。 相似文献
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季铵盐催化合成β-硝基对氯苯乙烯 总被引:2,自引:0,他引:2
以季铵盐PTCA作相转移催化剂,通过Henry反应,在醋酸铵/冰乙酸条件下,催化对氯苯甲醛与硝基甲烷缩合合成β-硝基对氯苯乙烯。考察了不同相转移催化剂的催化活性、最佳催化剂的用量、反应时间、反应温度、反应物料比等对反应的影响。在优化条件下,即以季铵盐PICA为相转移催化剂,反应物料比为对氯苯甲醛:硝基甲烷:PTCA=1:1.8:0.04,反应温度为78℃,反应时间为2h,在弱酸性条件下进行反应,产率达74.25%。实验结果表明:季铵盐PICA是一种优良的相转移催化剂。 相似文献
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通过酯交换反应合成了甲基丙烯酸异丁酯,并对反应条件进行优化;通过差式扫描量热法测定了磷钼钒杂多酸对甲基丙烯酸甲酯的阻聚性能,结果表明,随着杂多酸结构中钒钼比例数的增大、杂多酸用量的增加以及升温速率的提高,杂多酸的阻聚性能增强,且Dawson型杂多酸的阻聚性能高于Keggin型。在合成甲基丙烯酸异丁酯的反应中,经正交试验得到的最优反应条件为:醇酯物质的量比为1.2∶1,Dawson型磷钼钒杂多酸-V6催化剂(Dawson-V6)用量为反应物总质量的8%,反应时间7.5 h,磷钼钒杂多酸对不饱和酯的合成具有催化作用和较好的阻聚效果。 相似文献
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用稀土元素铈取代磷钼钒杂多酸合成了Keggin型稀土铈磷钼钒四元杂多酸盐(Ce HPMo11VO40·n H_2O),采用XRD和FTIR对该杂多酸盐的结构进行了表征。并将其作为催化剂应用于H_2O2氧化环己烷制备环己醇和环己酮的反应中,考察了催化剂用量、反应温度、反应时间、H_2O2用量对反应的影响。实验结果表明:反应最佳条件为n(环己烷)=0.1mol,n(Ce HPMo11VO40·n H_2O)=0.2 mmol、反应温度为75℃、反应时间为9 h、n(H_2O2)=0.2 mol(质量分数为30%),在此条件下,环己烷的转化率达到41.29%,环己醇和环己酮的总收率可达27.49%。 相似文献
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Jinjuan Xue Aili Wang Hengbo Yin Jingbo Wang Dongzhi Zhang Weiguang Chen Longbao Yu Tingshun Jiang 《Journal of Industrial and Engineering Chemistry》2010,16(2):288-292
A series of phosphotungstic quaternary ammonium salts, Q3 (PW12O40) and Q3(PW4O16) [Q = (C5H5)N+(C16H33), (C16H33)N+(CH3)3, (C4H9)4N+, and (CH3)4N+], were used as the catalysts in oxidation of cyclopentene. The catalysts [(C5H5)N(C16H33)]3(PW4O16) and [(C16H33)N(CH3)3]3(PW4O16) showed high catalytic activity in the selective oxidation of cyclopentene while using H2O2 (50%) as an oxidant and 2-propanol as a solvent. The oxidation products mainly consisted of glutaraldehyde, cis-1,2-cyclopentanediol and trans-1,2-cyclopentanediol. The above-mentioned two catalysts were dissolved completely in the reaction medium during the catalysis process and precipitated themselves from the reaction system after reaction, showing the characteristics of reaction-controlled phase-transfer catalysis. The types of quaternary ammonium cations and the phosphotungstic anions in phosphotungstic quaternary ammonium salts affected catalytic activity. 相似文献
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以钨酸钠、磷酸、过氧化氢(H_2O_2)和十六烷基三甲基氯化铵为原料制备了过氧磷钨酸季铵盐催化剂。通过FT-IR、TG对催化剂进行了结构和热稳定性的表征。在H_2O_2为氧化剂,无溶剂条件下,采用过氧磷钨酸季铵盐催化α-柏木烯环氧化合成环氧柏木烷。考察了各反应条件对环氧化反应的影响。结果表明,在反应温度60 ℃,反应时间3.5 h,H_2O_2与α-柏木烯摩尔比为1∶2,催化剂过氧磷钨酸季铵盐用量3.0% (以H_2O_2质量计,下同),助剂Na_2HPO_4用量1.6%条件下,环氧柏木烷的收率为65.7%,α-柏木烯的转化率为90.1%,环氧产物选择性可达72.9%。 相似文献
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Piao Cao Yuan Yuan Chizhou Huang Weizhen Sun Ling Zhao 《American Institute of Chemical Engineers》2020,66(8):e16979
Seven typical quaternary ammonium ionic liquids, amino acid ionic liquids, and imidazolium ionic liquids were synthesized, characterized, and investigated as co-catalyst for the sulfuric acid catalyzed isobutane alkylation. The results show that the introduction of [OPSIm][HSO4] or [Pr3NPS][HSO4] both leads to a better catalytic performance and higher quality of alkylate products. The molecular dynamic simulation indicates that the [OPSIm][HSO4] can promote the dissolution of isobutane molecules at interface, further improving the ratio of isobutane to olefin from 1.02 to 1.18. Differently, the [Pr3NPS][HSO4] can significantly increase the interface width from 0.66 to 0.97 nm and reduce the interface tension from 28.49 to 14.62 mN/m, thereby enhancing the reaction area and improving the ion transfer. The [Pro][HSO4] and [Gly][HSO4] result in a worse quality of alkylate products due to no positive effect on the interfacial properties such as interfacial solubility of isobutane. 相似文献
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Emulsifier‐free emulsion binary copolymerizations of styrene with four types of quaternary ammonium cationic monomers, diallyldimethylammonium chloride (DADMAC), (3‐(methacryloylamino) propyl) trimethyl ammonium chloride (MAPTAC), (2‐methacryloyloxy) ethyl) trimethyl ammonium chloride (MATMAC), and vinylbenzyl trimethyl ammonium chloride (VBTMAC), were conducted at 70°C. 2, 2'‐azobis (2‐methylpropionamidine) dihydrochloride (V50) and potassium persulphate (KPS) were used as cationic and anionic initiator, respectively. Ternary copolymerizations were also carried out in the presence of acrylamide as a second comonomer. Monomer conversions were followed by ultraviolet spectroscopy and the polymer microparticles were characterized using photon correlation spectroscopy, electrophoresis, colloid titration, and scanning electron microscopy. The results indicated that VBTMAC and MATMAC were highly reactive in the copolymerization with styrene whereas the incorporation of DADMAC was slow. MAPTAC had an intermediate reactivity. Binary copolymerization with VBTMAC, MATMAC, and MAPTAC produced particles smaller in size, but higher in surface‐charge density, than styrene homopolymer particles. However, significant agglomerates were detected in the VBTMAC and MATMAC‐containing latexes. In contrast, DADMAC‐containing polymer particles were almost identical to styrene particles. Continuous nucleation took place in the binary copolymerizations with VBTMAC and with MATMAC when using V50 initiator. In the case of using KPS, VBTMAC‐containing particles grew continuously to a mean size much larger than the corresponding particles initiated by V50. The presence of acrylamide reduced DADMAC‐containing particle size and diminished the agglomeration in the VBTMAC‐ and MATMAC‐containing latexes. The results were interpreted via particle formation mechanism. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1129–1140, 2000 相似文献