MFI分子筛前驱体对Y型沸石分子筛表面的修饰及其催化性质

间、对-甲基异丙苯是生产间、对-苯酚的反应中间体,因此其制备受到国内外广泛关注．ZSM-5,Y型,betn等沸石分子筛和掺杂zn的Al-MCM-41介孔分子筛在此反应中表现出不同的择形性．近年来利用沸石分子筛前驱体自组装技术合成的新型介孔材料已显示出优异的催化性能,     

在H型分子筛上萘与正己醇的烷基化反应

制备了H型分子筛HY,Hβ和HM,通过XRD,NH₃-TPD和Py-IR对其进行了表征,考察了其对萘与正己醇的烷基化反应的催化性质.结果表明,HY可作为己基化反应的催化剂,较高的反应温度和较长的反应时间对β-己基萘的生成有利.     

Characterization and Catalytic Activity of Titanium-containing Aluminum Phosphate Prepared by Sol-gel and Nonuniform Precipitation for O-Alkylation of Catechol with Ethanol

IntroductionThe monoalkylethers of catechol,for exam-ple,guaiacol( O- methoxyphenol) and guathol( O-ethoxyphenol) are important synthetic intermedi-ates for the production of various perfumes,medicines,the antioxidants and the stablizers ofsynthetic resins[1— 4] ,especially,they are widelyused for the synthesis of vanillin[1,2 ] .It is conven-tionally synthesized by the alkylation of O- ni-trylphenol with an alkyl halide in the presence ofbenzyl trialkyl ammonium bromide as a phase tran-siti…     

Bismuth-catalyzed methylation and alkylation of quinone derivatives with tert-butyl peroxybenzoate as an oxidant

A bismuth-catalyzed methylation of quinones in the presence of tert-butyl peroxybenzoate (TBPB) was developed via a radical reaction mechanism. Particularly, TBPB was used not only as an efficient oxidant, but also as a green methyl source in such transformation. Moreover, this method could also be efficiently extended to the alkylation of quinones. This reaction tolerated a series of functional groups and prepared a series of derivatives of vitamin K₃ and benzoquinone. Notably, antimalarial parvaquone was synthesized by the reaction.     

在SO42-/ZrO2上苯与丙烯的烷基化反应

制备了SO42 -/ZrO2 催化剂并采用X射线衍射、红外光谱仪测定、Py IR测定等技术对其进行了表征 .反应在自制高压流动床 (具有控温和冷凝 )装置上进行 ,原料以苯∶丙烯为 8∶1的比例配置于贮罐中 ,4 .0MPaN2 恒压 ,压入计量器后 ,用 8.0MPaN2 恒压 .反应后收集的液相产物由气相色谱 质谱 (GC MS)分析 ,产物分析在SE 5 4型毛细管色谱议上进行 .考察了苯与丙烯气相流动烷基化反应以及制备条件对催化活性的影响 ,结果表明 ,适当条件下制得的SO42 -/ZrO2 催化剂可用于合成异丙苯反应 ,并有高的丙烷转化率 (99.2 % )和高的异丙苯选择性(93.3% ) .     

Alkylation of p-cresol with tert-butanol catalyzed by heteropoly acid supported on zirconia catalyst

Butylation of p-cresol by tert-butanol was catalyzed by 12-tungstophosphoric acid supported on zirconia (TPA/ZrO₂) under flow conditions. Catalysts prepared with different TPA loading (5–30 wt.%) were calcined at 1023 K and acidity was estimated by temperature programmed desorption (TPD) of NH₃. Fifteen percent TPA/ZrO₂ showed the highest acidity and found to be the most active catalyst in butylation of p-cresol. The effects of temperature, space velocity (LHSV) and molar ratio of the reactants on the conversion of p-cresol and products selectivities were optimized and the optimum reaction conditions evaluated were 403 K, tert-butanol/p-cresol (Bu/Cr) molar ratio 3 and LHSV 4 h⁻¹. Under the optimized conditions, conversion of p-cresol was found to be 61 mol% with product selectivity for 2-tert-butyl-p-cresol (TBC) 81.4%, 2,6-di-tert-butyl-p-cresol (DTBC) 18.1% and tert-butyl-p-tolyl ether (ether) 0.5%. Study of time on stream (TOS) performed as a function of time for 100 h showed that the loss in activity in terms of conversion of p-cresol was 6%.     

利用双模板剂的多级孔ZSM-11分子筛的合成、表征和催化性能

ZSM-11与ZSM-5分子筛具有相似的孔道结构,通常表现出相似的催化性能,但近年来的研究发现,ZSM-11分子筛在某些反应过程具有明显优于ZSM-5的催化性能,因而逐渐引起科研界和工业界的广泛重视.但受其微孔尺寸的限制,在使用过程中往往容易积碳,并导致快速失活.为此,向微孔体系引入介孔制备多级孔ZSM-11分子筛是一种规避上述问题的有效方式.我们研究组前期已对分子筛进行碱处理脱硅及在该体系中加入CTAB制备多级孔分子筛进行了系统研究.在此基础上本文通过改变介孔模板剂十六烷基三甲基溴化铵(CTAB)和微孔模板剂四丁基溴化铵(TBABr)的摩尔比(R),采用一步法制备了一系列多级孔ZSM-11分子筛材料,并通过多种表征手段对材料的性质进行了系统研究.随着R值的增加,广角XRD测试结果表明,产物的结晶度逐渐下降,同时小角XRD测试结果表明产物中逐渐产生有序介孔相; XRF测试结果表明,产物的总包硅铝比呈上升趋势; SEM表征结果表明,首先棒状纳米晶团聚体形貌的ZSM-11分子筛的晶粒尺寸逐渐降低,随后晶粒之间插入无定形样品,直至最终产物几乎完全为无定形材料构成; TEM图片与上述表征结果一致,样品初始晶格条纹清晰且晶粒边缘规整,随后晶粒边缘开始弯曲不平,接着晶体样品中开始产生有序介孔材料,最终几乎完全变为有序介孔材料.综合上述表征结果和相关文献可推测,该有序介孔材料为类MCM-41材料.另外,我们采用N2物理吸附对材料的织构性质进行了考察,发现随着R值增大,产物的微孔减少,介孔增多.然而TEM结果表明,在类MCM-41产生之前,样品中介孔的增多并非来源于晶内孔,而是来源于晶粒之间的堆积孔,这是由于在合成过程中CTAB胶束嵌入ZSM-11的晶粒之间所导致.合成体系的碱度对产物的物化性质和织构性质也起了非常重要的作用.我们将这个体系与NaOH+CTAB对分子筛进行脱硅后处理体系进行了对比,发现虽然前者只能产生晶间孔而后者可产生晶内孔,但碱度对两者的作用相似,即降低碱度均可导致类MCM-41有序介孔相的产生.此外,还通过NH3-TPD和Py-IR技术对材料的酸性进行了考察.基于上述研究结果,提出了多级孔ZSM-11分子筛的形成机理.随着R值的变化,CTAB分别起了覆盖效应、胶束效应和模板效应.这些效应在合成多级孔ZSM-11分子筛过程中相互协同,同时又与TBABr的结构导向效应相互竞争,进而影响合成产物的孔结构、形貌、酸性以及用于二甲醚和苯烷基化的催化性能.     

Transalkylation of alkyl aryl sulfides with alkylating agents

The reaction of methyl iodide with tert-butylphenylsulfide in DMF leads to a transalkylation that produces methylphenylsulfide. This transalkylation reaction was further studied by ¹H NMR spectroscopy. The polarity of the solvent, the electron density on the sulfur atom, and the strength of the alkylating agent (MeI, EtI, BuI, dimethyl sulfate, or dimethyl carbonate) played important roles in the reaction. The suggested mechanism of the reaction involves the formation of a dialkyl aryl sulfonium salt that subsequently eliminates the radical. This mechanism was supported by the observation of higher conversion rates for compounds with more branched alkyl groups on the sulfur atom, which may lead to the formation of more stable radicals.     

含硫套索冠醚的合成

将二氮杂１８－冠－６的乙腈溶液分别与２－氯乙基烷基硫醚、２－氯乙基烯丙基硫醚、［２－（２－ｒ氯乙基）硫乙基］烷基硫醚在无水碳酸钾存在下反应制得５种新型侧链上含硫原子的双臂套索冠醚和５种新型单臂套索冠醚。它们的收率分别为３７％－７２％和１３％－３７％。此法比其它制备单臂套索冠醚的方法操作简单。     

树脂固载的β—酮砜的烷基化反应

Samuelsson等由季铵盐、碱和β-酮砜化合物制得相应的β-酮砜阴离子季铵盐,可直接用于烷基化反应。此法较经典方法虽有条件温和,产率较高的优点,但分离麻烦,季铵盐用量大且不能回收.聚合物负载的季铵盐作为相转移催化剂和反应底物的载体,已用于含活泼亚甲基化合物的烷基化反应.本文用离子交换法制得了大孔季铵盐离子固载的β-酮砜阴离子试剂,探索了这种试剂的烷基化反应条件,制得了一系列β-酮砜化合物的衍生物。