γ-Al_2O_3负载Cr促进SO_4~(-2)/ZrO_2固体超强酸研究

将 Cr促进的 SO2 - 4 /Zr O2 ( SZ)固体超强酸 Cr-SZ负载于 γ-Al2 O3载体上 ,制成 Cr-SZ/Al2 O3系列固体超强酸 ,利用探针反应考察了其超强酸性、中强酸性和弱酸性的变化情况 .详细研究了样品的比表面、硫含量、 Zr O2 晶化情况及正丁烷低温异构化反应活性 .结果发现 ,负载后部分 Cr-SZ的正丁烷低温异构化反应活性显著提高 .含铬样品酸强度和脱氢性能的增强对其正丁烷异构化反应活性的提高均有贡献 .样品酸性和脱氢性之间的合适匹配使 Cr-SZ/Al2 O3显示出很高的正丁烷异构化反应活性 .     

WO3/ZrO2固体酸催化剂的制备及应用研究进展

1979年,日本科学家Hino等人首先合成出SO4^2-／ZrO2固体超强酸并首次将其用于催化正丁烷异构化反应,发现其具有很好的异构化活性．但因在反应和再生处理过程中SO4^2-容易在H2和空气氛围中转变为H2S和SO2,     

脱铝超稳Y沸石的SiO2/Al2O3比与催化性能的研究

脱铝超稳Y沸石(简称DUSY)是八面沸石经脱铝改性后的固体酸催化材料,在石油化学工业和精细化学品合成中应用较广.我们曾报道了DUSY催化系列酯化反应,莰烯与乙酸的加成酯化反应[1],乙酸与β-苯乙醇的酯化反应[2],乙酸与烯丙醇的酯化反应[3],效果很好.克服了过去采用浓H2SO4作催化剂所带来的污染严重,设备腐蚀的问题,是具有应用前景的一类固体酸催化材料.谭志新等人曾报道α-蒎烯在固体超强酸上的异构化反应[4],王亚明等人报道了HMC-60催化α-蒎烯的异构化反应[5].与之相比较,用DUSY催化,其反应条件更温和.本文将DUSY的表面酸性与α-蒎烯异构反应相关联,探讨了硅铝比与催化性能的关系.     

制备条件及添加稀土对SO42- /ZrO2 -Al2O3固体超强酸酸性影响的研究

用共沉淀法制备了SO42-/ZrO2-Al2O3固体超强酸,并采用低温陈化和添加稀土La对其制备方法进行改进.通过样品催化正丁烷异构化反应考察了该固体超强酸中nZr和nAl的最佳配比为1∶ 2.该法制备的样品的IR显示,在1393 cm-1处的吸收峰强度较常温陈化样品大大增加.XRD分析表明,低温陈化和加入稀土添加剂的样品在650℃焙烧温度下,出现了亚稳态的ZrO2 四方晶相的晶体是表面酸性和催化活性增加的微观原因.样品催化合成八乙酸蔗糖酯反应结果同样证明,在相同的时间内,低温陈化和添加稀土添加剂的样品具有较好的催化活性.     

Sm2O3改性对S2O2-8/ZrO2-SiO2固体超强酸催化剂性能的影响

硫酸促进型固体超强酸催化剂具有极强的酸性,制备简单,在酯化、烷基化、酰基化等有机反应中催化活性高,可重复使用,对设备腐蚀小,环境友好,是一类具有广阔应用前景的新型绿色催化材料,已成为固体超强酸研究的热点之一。然而,目前该类催化剂使用成本高、比表面小、含硫基团容易流失、稳定性差,阻碍了其在工业上的推广和应用。为了探索和改善其催化性能,近年来多组分氧化物的固体超强酸开始引起人们的关注。     

SO42-/MxOy型固体超强酸催化剂研究(Ⅰ)

合成了一种新的SO₄^2-/M_xO_y型固体超强酸-SO₄^2-/ZrO₂-Fe₂O₅,研究了它对正戊烷反应的活性与选择性;制备并测定了SO₄^2-/TiO₂固体超强酸对正戊烷的异构化活性与裂解活性及其某些物性;重复合成了文献报导的SO₄^2-/ZrO₂固体超强酸并测定了它对正戊烷异构化的催化性能,表明所采用的测定方法与所得结果可与文献值相比较。     

表征固体超强酸性的新方法--正丁烷异构化反应的原位13C MAS NMR谱

室温下SO2 -4/ZrO2 催化剂 (SZ)上13 C标记的正丁烷异构化反应的原位13 CMASNMR谱研究结果表明 :其反应动力学符合Langmuir Hinshelwood一级可逆表面反应动力学公式 ,由该动力学公式计算得到的反应速率常数可以用于衡量固体催化剂的表面超强酸性 .这种新的表征方法显示采用一步 -醇热 -超临界干燥综合技术合成的SZ催化剂不仅比表面和硫酸根含量高 ,而且其超强酸性和异构化反应活性均明显优于常规法合成的催化剂 ,具有良好的应用前景 .     

固体超强酸AlCl3.Fe2（SO4）3的研究

自60年代末Olah等人研究液体超强酸以来,超强酸的催化作用的研究迅速发展。由于多相催化比均相催化具有许多优越性,人们对固体超强酸催化剂进行了广泛的研究。Ma-gnatta等报道AlCl_3与聚苯磺酸络合物在85℃下,能使已烷裂解异构化。Olah等发展了全氟磺酸树脂Nafion-H固体超强酸催     

脱铝超稳Y沸石的SiO_2/Al_2O_3比与催化性能的研究

脱铝超稳Ｙ沸石 (简称ＤＵＳＹ)是八面沸石经脱铝改性后的固体酸催化材料 ,在石油化学工业和精细化学品合成中应用较广。我们曾报道了ＤＵＳＹ催化系列酯化反应 ,莰烯与乙酸的加成酯化反应[1] ,乙酸与β 苯乙醇的酯化反应[2 ] ,乙酸与烯丙醇的酯化反应[3] ,效果很好。克服了过去采用浓Ｈ2 ＳＯ4 作催化剂所带来的污染严重 ,设备腐蚀的问题 ,是具有应用前景的一类固体酸催化材料。谭志新等人曾报道α 蒎烯在固体超强酸上的异构化反应[4 ] ,王亚明等人报道了ＨＭＣ 60催化α 蒎烯的异构化反应[5] 。与之相比较 ,用ＤＵＳＹ催化 ,其反应条件更…     

低温陈化法制备SO42-/WO3-TiO2固体超强酸及性能研究

固体超强酸的研制是近20年来催化领域中的热点研究课题之一。起初，人们所研制的SO4^2-/MxOy型固体超强酸中，MxOy多为ZrO2。近年来，研究者们为得到高酸强度和高催化活性的固体超强酸催化剂，以ZrO2为主体，引入第二组分、第三组分组成复合型催化剂，这方面的研究者颇多，也取得了一     

丝光沸石负载SO~4^2^-/ZrO~2超强酸的研究

制备了一系列丝光沸石(HM)负载SO~4^2^-/ZrO~2(SZ)超强酸催化剂,并研究了它们比表面、孔容、硫含量及超强酸性的变化规律。结果发现,HM在负载SZ后超强酸性显著提高,可以在35℃条件下催化正丁烷异构化反应。吡啶吸附红外结果表明,适量负载SZ可增加HM的Lewis酸量和总酸量,从而使甲苯岐化和邻二甲苯异构化反应等酸催化反应活性显著提高。XRD结果证实,在HM上负载适量SZ不会破坏HM的结构,但负载量过大(>60%,质量分数)则会引起沸石结构的塌毁。     

SO4^2—／ZrO2的相结构和超强酸性及其对丁烷异构化反应的催化活性

通过沉淀、回流和掺杂等方法制备了ZrO2呈四方相及单斜相的SO4^2-／ZrO2（SZ），并用XRD，TEM，低温N2－BET和吡啶吸附IR等技术定量测量地测定和探讨了SZ的结构特征和表面超强酸性及其对丁烷异构化反应的催化活性，结果表明，ZrO2呈单斜相结构的SZ表面Broensted（B）酸与Lewis（L）酸的浓度比[B]/[L]较ZrO2以四方相为主的SZ高约40％，但其对丁烷异构化反应的比催化活性则较后者低约31％，由掺Mg^2 所制备的ZrO2呈四方相的SMZ具有与ZrO2呈纯单斜相的SZ非常接近的[B]/[L]比，且表现出比末掺Mg^2 的ZrO2以四方相为主的SZ更高的比催化活性，从催化剂晶结构对表面B酸浓度及强度影响的角度进行了讨论。     

Effect of Mn and Fe on the reactivity of sulfated zirconia toward H2 and n-butane: a diffuse reflectance IR spectroscopic investigation

Sulfated zirconia (SZ) and sulfated zirconia promoted with 2 wt % manganese (MnSZ) or iron (FeSZ), all active in n-butane isomerization, were investigated using diffuse reflectance Fourier transform IR spectroscopy (DRIFTS). By adsorption of H(2) at 77 K or of n-butane at room temperature, it was found that the promoters neither enhance the Lewis nor the Br?nsted acid strength. SZ and promoted SZ do not exhibit higher acid strength than zeolites. In a batch experiment using 70 hPa of H(2), SZ did not react at 473 K. Reaction of H(2) with MnSZ produced water (band at 5242 cm(-1)) and a decrease in the sulfate groups (multiple bands). Heating of SZ in 10 hPa n-butane to 573 K caused total reduction of sulfate to H(2)S (2583, 2570 cm(-1)) and partial and total oxidation of butane to olefinic species (3062 cm(-1)), CO(2), and water. MnSZ and FeSZ reacted with n-butane already at 373 K; products of skeletal isomerization (methyne CH vibration at 2910 cm(-1)) were detected and sulfate groups were consumed. Rather than increasing the acidity, the promoters enhance the oxidation potential of sulfate and facilitate alkane activation via oxidative dehydrogenation.     

Butane isomerization over platinum promoted sulfated zirconia catalysts

The isomerization of n-butane to i-butane has been studied at 11 bar in a microflow reactor over sulfated zirconia (SZ) and platinum containing sulfated zirconia (Pt-SZ) catalysts. In the presence of H₂ a significantly higher temperature is required for isomerization over SZ than in its absence. The rate over SZ is higher with n-butane containing 33 ppm butene as an impurity than with a feed that is pre-equilibrated over a Pt/SiO₂ catalyst to a much lower butene content. Over Pt-SZ the reaction rate is higher, because any butene consumed is rapidly regenerated; the conversion is perfectly stable in 83 h runs, selectivity to i-butane is 95%; i-pentane and propane are the main byproducts. The activation energy is 53 kJ mol⁻¹. Upon increasing the pressure of H₂ from 1.1 to 6.6 bar, the reaction rate was found to decrease in a perfectly reversible fashion. Kinetic analysis reveals that the reaction order is negative in H₂ (−1.1 to −1.3 depending on the temperature) and positive in n-butane (+ 1.3 to +1.6), indicating that the mechanism of this isomerization is intermolecular: butene is formed and reacts with adsorbed C₄-carbenium ions to adsorbed C₈ intermediates which isomerize and undergo β-fission to fragments with i-C₄ structure. This mechanism is confirmed over Pt-SZ by isotopic labelling experiments, though at much lower pressure, using double labelled ¹³CH₃---CH₂---CH₂---¹³CH₃. The primary reaction product consists of i-butane molecules, containing zero, one, two, three and four ¹³C atoms in a binomial distribution.     

表征固体超强酸性的新方法-正丁烷异构化反应的原位~(13)CMASNMR谱

室温下SO_4~(2-)/ZrO_2催化剂（SZ）上~(13)C标记的丁烷异构化反应的原位 ~(13)C MAS NMR谱研究结果表明：其反应动力学符合Langmuir-Hinshelwood一级可 逆表面反应动力学公式，由该动力学公式计算得到的反应速率常数可以用于衡量固 体催化剂的表面超强酸性。这种新的表征方法显示采用一步-醇热-超临界干燥综合 技术合成的SZ催化剂不仅比表面和硫酸根含量高，而且其超强酸性和异构化反应活 性均明显优于常规法合成的催化剂，具有良好的应用前景。     

Highly effective sulfated zirconia nanocatalysts grown out of colloidal silica at high temperature

A large surface-to-volume ratio is a prerequisite for highly effective catalysts. Making catalysts in the form of nanoparticles provides a good way to achieve the aim. However, agglomeration of nanoparticles during the preparation and utilization of nanocatalysts remains a formidable problem. Here, we present a novel approach in which nano units of catalysts are formed in the matrix of a colloidal carrier, with assistance of a cross-linking agent, and then grow out of the carrier upon calcination at high temperature. This ensures that the catalysts not only do not agglomerate, but also have a low cost and high catalytic efficiency due to the large surface-to-volume ratio and the absence of carbon deposition. The technique is demonstrated by the successful preparation of a binary nanocatalyst that consists of a silica nanoparticle core and a sulfated zirconia (SZ) nanocrystal shell (JML-1). The synthesis was achieved by converting sulfated zirconia (SZ) and silica solutions into a composite gel by means of sol-gel processing in the presence of triethoxysilane as the cross-linking agent, followed by heating at 50 degrees C and calcining at 550 degrees C. Relative to other catalysts, such as pure SZ, non-nanodispersed SZ over silica (SZ/SiO2), and zeolites Y, Beta, and ZSM-5, JML-1 exhibits superior catalytic activity in many reactions. For example, the activity of JML-1 in the production of gasoline by alkylation of 1-butene with isobutene remained at 95% or higher after 20 h of reaction and was over 90% after being regenerated five times. In sharp contrast, SZ and SZ/SiO2 give a high activity only for 2 h and the initial activity of zeolites Beta and ZSM-5 are about 88 and 60%, respectively. These findings demonstrate that non-agglomerated nanoparticles anchored onto a carrier surface can be prepared and the technique provides a versatile route to new highly effective nanocatalyst systems.     

静电纺丝法制备硫酸化的二氧化锆/二氧化硅复合纤维

将电纺丝技术与溶胶-凝胶技术相结合, 制备了SZ粒子分布于SiO2纤维外壁的硫酸化的二氧化锆/二氧化硅复合纤维. 与常见的SZ复合催化剂相比, 采用SiO2纤维负载SZ不仅可以解决粉体材料带来的难以与反应体系分离等弊病, 同时功能粒子SZ分布与纤维外壁的结构也提高了功能粒子的利用率.     

New process to control hydrolysis step during sol-gel preparation of sulfated zirconia catalysts

Sulfated zirconia catalysts were prepared by sol-gel process using a new method allowing the control of the hydrolysis step of zirconium alkoxides. Prepared samples were characterized by N₂ adsorption (desorption) at 77 K, XRD, chemical analysis of total sulfur and XPS. Catalytic properties have been evaluated in n-butane and n-hexane isomerization reactions. Obtained results show that time necessary for gelation is significant and depends considerably on the nature of the zirconium precursor. Concerning the properties of the solids obtained by this method, it has been noted that the use of the zirconium propoxide led to a better retention of the sulfate species, which improves activity during isomerization reactions. It has been found also that an initial S/Zr molar ratio equal to 0.5 allowed to obtain an optimal sulfur content and a high specific surface area.     

Comparative study of regioselective synthesis of beta-aminoalcohols under solventless conditions catalyzed by sulfated zirconia and SZ/MCM-41

Sulfated zirconia and SZ/MCM-41 were used as catalysts for the synthesis of beta-aminoalcohols via epoxide aminolysis. Sulfated zirconia was prepared by sol-gel and SZ/MCM-41 was obtained by impregnation. Solid catalysts were characterized by XRD, SEM-EDS, UV-Vis, FT-IR pyridine desorption and Nitrogen physisorption. Both acid materials were useful as catalysts, even when they were recycled several times. The beta-aminoalcohols were characterized by FT-IR, (1)H- and (13)C-NMR and GC-MS.