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1.
具有中孔结构的SO2-4/Zr-HMS型固体超强酸的合成和结构表征   总被引:5,自引:0,他引:5  
用TEOS-Zr-HAD-H2O-Ethanol体系合成了Zr-HMS的中孔分子筛, 脱除模板剂后用0.5 mol/L硫酸处理和550 ℃高温焙烧3 h, 制得一种中孔SO2-4/Zr-HMS超强酸催化剂. 采用XRD对其结构进行表征. 用指示剂法、 TG和NH3-TPD对其酸性进行了表征. 结果表明, 经过一系列处理后制得的SO2-4/Zr-HMS催化剂具备HMS中孔分子筛的结构特征, 其酸强度可达H0=-13.75. 在锆及SO2-4含量远远低于SO2-4/ZrO2的条件下, SO2-4/Zr-HMS催化剂对于苯酐和正丁醇酯化反应的活性仍高于SO2-4/ZrO2催化剂.  相似文献   

2.
SO42-促进的中孔含锆分子筛催化合成乙酸松油酯的研究   总被引:12,自引:0,他引:12  
合成了中孔含锆分子筛Zr-MCM-41,用H2SO4对Zr-MCM-41进行修饰,得到SO4^2-促进的中孔含锆分子筛SO4^2-/Zr-MCM-41.通过XRD、FT—IR表征了其结构.结果表明:Zr—MCM-41和SO4^2-/Zr—MCM-41具有中孔分子筛的特征结构、良好的长程有序性和结晶度;SO4^2-已进入Zr—MCM-41骨架内部,并与骨架原子形成了化学键,从而产生强酸中心,将SO4^2-/Zr—MCM-41用于催化合成乙酸松油酯,考察了催化剂的种类、反应温度、反应时间及反应物配比对松油醇酯化反应结果的影响.  相似文献   

3.
以硅溶胶和氧氯化锆为硅源和锆源,采用水热合成的方法制得具有ZSM-5结构的Zr-Si分子筛;用0.5mol/L的硫酸处理该分子筛,并在550℃焙烧,制得具有ZSM-5结构的SO4^2-/ZrO2-SiO2分子筛型的固体超强酸。采用XRD、SEM、TG、IR、NH3-PHD和指示剂法对其结构和酸性进行表征。结果表明,该SO4^2-/ZrO2-SiO2具有ZSM-5结构和超强酸性,其酸强度大于-13.75,且具有良好的热稳定性。  相似文献   

4.
本文研究了固体酸烷基化反应催化剂H3PO4-BF3/ZrO2及H3PO4-BF3-H2SO4/ZrO2的酸性及其结构。用指示剂法及正丁胺滴定法测定了催化剂的酸强度及酸量;用吸附吡啶的红外光谱法研究了催化剂的表面酸类型;用FT-IR、XPS、XRD、DTA-TG及TPDE等方法研究了催化剂的结构。结果表明;两种催化剂表面均只有Broensted酸,酸强度为-8.2<H0≤-5.6。H3PO4-BF3/ZrO2中,活性组分强能是以H2PO4^-:BF3的形态存在,BF3通过与H2O4^-的络合作用是催化剂的活性增强。H3PO4-BF3/ZrO2中,存在H2SO4与ZrO2的成盐作用,同时亦有可能存在H2SO4与H3PO4、BF3之间的相互作用。催化剂在下焙烧失活的主要原因是H2PO4^-失水生成P2O7^4-,使催化剂表面质子酸量大幅度降低所致。  相似文献   

5.
新型固体超强酸催化剂的制备与裂解性能研究   总被引:7,自引:0,他引:7  
采用浸渍法,将活性超强酸SO4^2-/ZrO2引入Si-MCM-41介孔分子筛,得到一种新型的固体超强酸催化剂SO4^2-/ZrO2 /Si-MCM-41,其PKA值可达-12.7,酸度分布曲线表明强酸中心数量远低于弱酸中心,XRD结果显示,Si-MCM-41骨架部分塌陷,但保留了主要骨架结构,采用Py-IP法,测定SO4^2-/ZrO2 /Si-MCM-41上酸类型以L酸为主,在催化1,3,5-三异丙苯裂解反应中该催化剂的性能优于微孔分子筛。  相似文献   

6.
一硝基氯苯的区域选择性合成研究   总被引:5,自引:0,他引:5  
制备了SO4^2-/TiO2、SO4^-/ZrO2和一系列钛锆原子比不同的SO4^2-/TiO2-ZrO2固体酸催化剂,并通过XRD、FTIR和TG-DTA等进行了表征;研究了这些催化剂上硝酸硝化氯苯的区域选择性。结果表明,在醋酐存在下,氯苯与等物质量的硝酸反应,其产物具有强位选择性,在SO4^2-/TiO2-ZrO2(原子比1:2)催化剂上,氯苯一硝化产物中邻/对硝基氯苯异构体的质量比达0.29,较硝友混酸消化的0.57显著降低,产物得率可达70.2%,该反应快速且催化剂可循环使用。  相似文献   

7.
 制备了Mo-MCM-41中孔分子筛,并将BO3-3引入到分子筛中制得BO3-3/Mo-MCM-41催化剂.采用XRD,FT-IR,ESR,BET和NH3-TPD对分子筛催化剂的结构及酸强度进行了表征.结果表明,Mo-MCM-41和BO3-3/Mo-MCM-41具有中孔分子筛的特征,有良好的长程有序 性和结晶度;但Mo并未进入分子筛骨架内部而是在分子筛表面以MoO2的形式存在;BO3-3附着于Mo-MCM-41分子筛上形成强酸中心.将BO3-3/Mo-MCM-41用于催化2-甲氧基萘乙酰化反应,考察了催化剂用量、Si/Mo比及BO3-3的引入方式对该反应性能的影响,发现BO3-3/Mo-MCM-41对2-甲氧基萘乙酰化反应具有良好的催化性能.  相似文献   

8.
通过沉淀、回流和浸渍法制备了镓掺杂的纳米级固体超强酸SO4^2-/Ga2O3/ZrO2,并用X射线衍射、透射电镜、热重、吡啶吸附红外光谱、低温N2-BET及化学分析等技术对SO4^2-/Ga2O3/ZrO2的结构、表面性质及其对正丁烷异构化反应的催化活性进行了研究.结果表明,掺杂Ga2O3可以抑制制备过程中ZrO2晶粒长大,有利于抑制高温下催化剂由四方相转变为单斜相.与未掺杂的催化剂相比,Ga2O3的掺杂提高了催化剂表面SO4^2-的分解温度,有利于催化剂表面形成更多的酸中心.SO4^2-/Ga2O3/ZrO2对正丁烷异构化反应显示出优异的催化性能.其中,含3%Ga2O3的样品的活性最高,220℃下其初活性为59.1%;反应1h后,其活性基本保持稳定,稳态转化率大于51%,接近该反应条件下正丁烷的平衡转化率.  相似文献   

9.
 以HMS,MCM-41,AlHMS和ZrO2/HMS等中孔分子筛为载体,采用孔体积浸渍法制备了系列负载型钴催化剂.XRD测定结果表明,Co氧化物完全分散于分子筛内表面,载体仍保持中孔分子筛的特征;低温N2吸附测定结果表明,表面负载金属钴后,分子筛的比表面积和孔体积下降,孔径减小,孔壁增厚.比较了不同中孔分子筛负载Co催化剂在F-T反应中的催化性能,以短程六角对称的HMS为载体,有利于F-T反应中的链增长,烃类产物主要为微晶蜡;以ZrO2/HMS为载体可抑制CH4的生成,提高C5+的选择性.  相似文献   

10.
低温陈化超声波共沉淀法制得SO4^2-/ZrO2-La2O3前驱体,经H2SO4处理,在不同温度下焙烧得到纳米晶催化剂SO4^2-/ZrO2-La2O3;用Hammett指示剂法测定其酸性.用XRD、BET、TEM、IR和XPS对样品进行表征,其催化活性用醋酸和甘油的酯化反应进行了评价.结果表明经超声波搅拌和低温(-15℃)陈化,650℃焙烧4h得到的固体超强酸表现出较高催化活性.  相似文献   

11.
A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.  相似文献   

12.
The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp3)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp2)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp2)?H and aliphatic 1,5- and 1,6-C(sp3)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp3)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp2)?H insertion.  相似文献   

13.
N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).  相似文献   

14.
An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y1 and Y2. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.  相似文献   

15.
In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.  相似文献   

16.
Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.  相似文献   

17.
用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.  相似文献   

18.
19.
A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu0 as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than CuI in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).  相似文献   

20.
(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C60, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.  相似文献   

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