油溶性氧化剂对二苯并噻吩类的氧化脱硫研究

随着环保要求越来越严格,生产低硫燃料特别是超低硫燃料是大势所趋。氧化脱硫由于反应条件温和、不消耗大量氢气、投资少且对硫醇有很好的脱除效果等优点,是目前研究的热点。当前,无论是用过氧酸,三氟乙酸还是双氧水,最大的问题是它们都为水溶性氧化剂。在氧化过程中易使油品再次发生乳化或部分乳化现象;此外,水溶性氧化剂需要与油品充分混合才能使其反应,局限在锅式反应器中,不易连续工艺化。目前国内仅有对水溶性氧化剂的报道。实验中改用油溶性氧化剂,以氧化钼作为催化剂来进行氧化脱硫的研究。初步筛选出合适的油溶性氧化剂为过氧化叔戊醇(t-autyl hy-droperoxide,TAHP),取得了较好的脱硫效果。油溶性氧化剂TAHP的合成改进方面,考察了反应物的添加顺序、反应物配料比,WSHV及碱液浓度对合成精制的影响,得出了较佳的反应条件;产率从文献的38%提高到68%,时间从24h缩短到2h;为大批量生产此氧化剂奠定基础;产品通过红外表征;碘量法标定含量95%以上。以DBT的十氢蔡液作为含硫模拟油品,以油溶性的TAHP为氧化剂进行氧化脱硫的研究。考察了氧化剂用量、WHSV和催化剂等因素对DBT脱除率的影响。通过正交试验和单因素试验找到了最佳脱除条件,DBT的脱除率达87%以上,模拟油品回收率达99%。"D113"型丙烯酸系弱酸性阳离子交换树脂上负载三氧化铝作为非均相催化剂,加大了TAHP与MoO3岛的接触面积,催化剂用量显著降低。催化剂重复使用10次后,脱硫效果依然理想。探讨了TAHP在MoO3催化下的氧化机理。     

纳米技术在石化领域的应用及市场导向（续）

瑞士技术研究院开发了一种低费用、高效的纳米颗粒二氧化钛-二氧化硅催化剂，可应用于环氧化反应。环氧化物是生产许多聚合物、表面活性剂和医药的关键中间体。与传统的环氧化催化济相比，这种催化剂可大大提高转化率。它们基于相同的材料，但产生副产物很少，同时更高效和更稳定。     

纳米技术在石化领域的应用及市场导向（续）

英美研究人员采用纳米金并添加微量铋而开发的催化剂，可用于烃类的选择性氧化。该催化剂可在无溶剂条件下和仅采用氧作为氧化剂进行反应，使反应与采用氯气的工业过程相比更为环境友好，同时费用大大低于采用有机过氧化物的反应过程。该工艺也可望广泛用于有机中间体如酸类、醇类、醛类、环氧化物和酮类的工业生产。     

环氧化天然橡胶在胶乳及四氢呋喃体系中的降解研究

以天然橡胶为原料,经环氧化反应在天然橡胶分子链上引入环氧基制得环氧化天然橡胶;环氧化天然橡胶经高碘酸降解生成了端羰基遥爪型液体天然橡胶。探讨了在胶乳相和四氢呋喃溶剂中高碘酸用量和环氧化天然橡胶环氧化程度对遥爪型液体天然橡胶粘均分子量的影响,产物结构经红外和核磁表征。结果表明,增加氧化剂用量、提高环氧化天然橡胶的环氧化程度均可有效降低液体天然橡胶的分子量;在四氢呋喃溶剂中,环氧化天然橡胶的环氧化程度对液体天然橡胶的粘均分子量具有决定性作用;降解产物具有端羰基结构。     

钒基催化剂上丙烷氧化脱氢催化性能研究进展

低碳烷烃作为一种资源丰富且廉价的原料,利用其可制取具有高附加值的烯烃和含氧衍生物,对缓解丙烯和石油资源短缺具有重要的价值。但丙烷在高温下易深度氧化和深度裂解,且催化剂易积碳失活,使得丙烯选择性降低,故迫切需要开发低温高效的催化剂。简要介绍了丙烷氧化脱氢制丙烯的研究意义和钒基催化剂上丙烷氧化脱氢反应的机理,综述了负载型钒基催化剂的载体类型及性质、活性物种引入方式、表面钒物种的还原性能、钒负载量、氧化剂的选择对丙烷氧化脱氢催化活性及对丙烯选择性的影响。     

钯金双金属催化剂的制备及其在燃料电池中的应用进展

与单金属原子催化剂相比，双金属原子催化剂可以打破反应中间体的吸附能和协同效应的比例关系，在燃料电池相关反应具有良好的活性。本文阐述了用于电催化反应的PdAu双金属催化剂的合成方法以及PdAu双金属催化剂的不同结构对性能的影响，并综述了PdAu双金属催化剂用于燃料电池相关反应(包括氧还原反应、甲醇氧化反应、乙醇氧化反应和甲酸氧化反应)的最新研究进展，最后提出了PdAu双金属催化剂存在的不足并对在燃料电池中高效利用的未来方向提出了个人观点。     

负载杂多酸簇的UiO-67的制备及其催化活性研究

利用溶剂热合成法制备了金属有机骨架材料UiO-67,采用后修饰法将多金属氧酸盐负载到其表面，得到UiO-67-bpy-NiMo₁₁复合材料。利用FT-IR、XRD、TGA、N₂物理吸附和SEM表征手段对制备的材料进行结构表征；利用自制的MOFs材料催化氧化二甲基硫醚制备二甲基亚砜，考察了五种UiO系列MOFs催化剂、溶剂种类、反应时间及氧化剂用量等对氧化反应的影响，确定最佳反应条件。结果表明，UiO-67-bpy-NiMo₁₁对二甲基硫醚的氧化反应具有优秀的催化活性，在循环使用五次后，仍然保持较好的催化活性。     

一种新型螺环酚醛树脂的制备及性能研究

以氮甲基苯胺和苯丙炔酸为原料合成了底物N-甲基-N-苯基-3-丙炔酰胺,叔丁基过氧化氢(TBHP)作氧化剂,三溴化铁作催化剂,通过串联反应发生分子内环化反应生成3-溴-螺[4,5]-三烯酮,进一步与低模量酚醛树脂反应生成螺环酚醛树脂。实验探讨并优化了影响合成反应的因素,对合成的螺环酚醛树脂进行了表征和性能测试,结果令人满意。     

钛柱撑蒙脱土光催化剂的制备及其深度脱硫性能的研究

采用溶胶-凝胶法制备出一种新型钛柱撑型光催化剂,并研究了它在模拟汽油体系中的光催化氧化深度脱硫性能.反应体系以氧气为氧化剂,自制光催化剂,紫外光激发,在正辛烷和乙腈两相中反应,硫化物被氧化为极性物质从正辛烷进入乙腈萃取相,从而达到深度脱硫的目的.采用X射线衍射、傅立叶变换红外光谱等对制备的催化剂进行了结构表征.对不同热处理条件下的催化剂催化性能、反应时间、催化剂用量以及剂油比等因素影响进行了考察.结果表明:经350℃热处理的催化剂具有较好的光催化性能,6小时内,可将模拟物系中的硫含量由400μg/g降到30μg/g.     

不同氧化条件下氧化马铃薯淀粉胶粘剂影响因素的研究

选用马铃薯淀粉为原料,双氧水为氧化剂,以淀粉用量、氧化剂用量、反应温度、反应时间和pH值为影响因素,按L25(56)正交实验表分别在一般氧化和高氧化条件下制备2组氧化淀粉,然后再配成胶粘剂,测定了粘度、快干性、耐水性,最后通过分析和讨论,总结出了在2种氧化条件下各正交因素对胶粘剂相关性能的影响规律,寻求到了性能相对较佳的氧化淀粉反应条件和配方.     

Catalytic activity of multi-wall carbon nanotube supported manganese (III) porphyrin: an efficient,selective and reusable catalyst for oxidation of alkenes and alkanes with urea–hydrogen peroxide

Manganese complex of meso-tetrakis(4-hydroxyphenyl)porphyrin immobilised onto functionalised multi-wall carbon nanotubes (MWCNT) has been synthesised and characterised by elemental analysis, Fourier transform infrared (FT-IR), ultraviolet-visible (UV-Vis) spectroscopy, powder X-ray diffraction and scanning electron microscopy. This catalyst, [Mn(THPP)OAc@MWCNT], was successfully applied for efficient epoxidation of alkenes and alkanes with urea–hydrogen peroxide. The role of the stoichiometric amounts of the acetic anhydride as an oxidant activator which introduce in situ peracetic acid has been discussed. This heterogeneous catalyst was highly reusable in the oxidation reactions and reused several times without significant loss of its catalytic activity.     

无水AlCl_3作用下EPDM的交联与接枝性能

以无水AlCl3为催化剂,在溶液体系考察了温度、催化剂用量、溶剂品种等因素对乙丙三元橡胶(EPDM)交联与接枝性能的影响。结果显示,无水AlCl3可以引发EPDM间产生交联反应;温度较低时,EPDM交联反应困难,但乙丙三元橡胶与聚苯乙烯(PS)间产生了接枝反应;在苯与二甲苯溶剂中不易形成活性正碳离子;催化剂用量增大,凝胶含量与交联密度增大;PS进入EPDM凝胶网络,使PS相热稳定性提高,玻璃化温度提高。     

Tetra-substituted cobalt (II) phthalocyanine/multi-walled carbon nanotubes as new efficient catalyst for the selective oxidation of styrene using tert-butyl hydroperoxide

Abstract

A novel tert-butyl hydroperoxide tetrasubstituted cobalt phthalocyanine (CoPc(OC₁₀H₁₄N)₄) was synthesized by the classical phthalonitrile method. Subsequently, the cobalt phthalocyanine (CoPc) was immobilized on the multi-walled carbon nanotubes (MWCNTs) by ultrasonic impregnation method to obtain CoPc(OC₁₀H₁₄N)₄/MWCNTs composites. The obtained composites were characterized by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscope (SEM) and diffuse reflectance spectra (DRS) techniques. Using tert-butyl hydroperoxide (TBHP) as an environmentally friendly oxidant, CoPc(OC₁₀H₁₄N)₄/MWCNTs composites can be used as effective catalysts for the epoxidation of styrene. The effects of various variables, such as the mass ratio of CoPc(OC₁₀H₁₄N)₄/MWCNTs, reaction time, temperature, molar ratio of substrate/oxidant and the amount of catalyst on the catalytic capability were evaluated. The conversion of styrene reached 97.15%, and the epoxidation product achieved the selectivity of 84.44% under the optimal reaction conditions.     

A new type of heterogeneous epoxidation catalysts polyamines molybdenum (VI) complexes grafted on zirconium oligo-styrenyl phosphonate hydrogen phosphate

A new type of inorganic-organic hybrid materials — zirconium oligo-styrenyl phosphonate hydrogen phosphate (ZSPP) was designed and synthesized. Four kinds of new heterogeneous catalysts for olefin epoxidation were obtained by grafting polyamines on ZSPP and subsequently coordinating with MoO₂(acac)₂. The catalysts were characterized by IR, Raman, XPS, XRD and elemental analysis. The catalytic activities of the prepared catalysts were evaluated through the epoxidation of cyclohexene using TBHP as oxidant. The results revealed that these catalysts possessed high conversion, selectivity and reusability, but with increasing numbers of nitrogen atoms in ligands, the conversion and selectivity gradually decreased.     

Iron(III) porphyrin anchored onto organosilylated multiwalled carbon nanotubes as an active catalyst for epoxidation reactions under mild conditions

The immobilization of an efficient iron(III) porphyrin catalyst onto multiwalled carbon nanotubes (MWCNT) is reported through a quaternization reaction between the dimethylamine-tetrafluorophenyl groups of the metalloporphyrin and the bromoalkyl moieties attached on the nanotubes surface. Prefunctionalization of MWCNT considered its direct reaction with 4-hydroxyaniline to introduce hydroxyphenyl groups on the nanotube sidewalls, followed by silylation with a bromoalkylorganosilane. The preparation of the catalysts was performed in conventional and microwave heating, and the obtained materials were characterized by XPS, TGA, FTIR, and XRD. Although the two procedures led to similar functionalization degree, the microwave-assisted synthesis allowed the anchoring reaction to be performed in 1 h, reducing significantly the reaction time relatively to conventional heating. For both materials, the catalyst loading was 76 μmol g^?1 based on the iron content obtained by XPS. The materials were tested as recyclable catalysts in the epoxidation of cis-cyclooctene by hydrogen peroxide as a green oxidant at room temperature, and in ethanol as a cheap and environmental compatible solvent with no need of other additives. A 95 % conversion and 100 % selectivity towards the epoxide were obtained after 5 h of reaction time, and the reutilization of the catalysts, upon three cycles, was more efficient when the rate of H₂O₂ addition was 0.5 molar equivalents h^?1.     

RuO2 supported on V2O5–Al2O3 material as heterogeneous catalyst for cyclohexane oxidation reaction

RuO₂ supported on V₂O₅–Al₂O₃ mixed oxide material was prepared by impregnation method and characterized by XRD, nitrogen adsorption–desorption, SEM, UV-visible and FT–IR spectroscopic techniques. The catalytic activity of the prepared catalyst was evaluated for the liquid-phase oxidation of cyclohexane under mild conditions. In this reaction, conversion of cyclohexane to cyclohexanol and cyclohexanone and the selectivity ratio of cyclohexanol to cyclohexanone were greatly affected by the solvent and the oxidant agent used. The results show that the catalyst exhibit good conversion in polar solvents. The use of acetic acid gives more than 26% conversion in presence of TBHP as oxidant and an ~40% conversion with hydrogen peroxide as oxidant in presence of an initiator, with 92% selectivity for cyclohexanol product.     

Multi-wall carbon nanotubes supported molybdenyl acetylacetonate: Efficient and highly reusable catalysts for epoxidation of alkenes with tert-butyl hydroperoxide

Efficient epoxidation of olefins catalyzed by MoO₂(acac)₂ supported on amines functionalized MWCNTs is reported. The MWCNTs bearing carboxylic acid groups were modified with 2-aminophenol and 2-aminothiophenol. These amine–MWCNTs act as bidentate ligand for attachment of Mo catalyst. These catalysts were characterized by elemental analysis, scanning electron microscopy, FT-IR and diffuse reflectance UV–Vis spectroscopic methods. The prepared catalysts were used for efficient epoxidation of different alkenes such as cyclic and linear ones with tert-butyl hydroperoxide in refluxing 1,2-dichloroethane. These heterogeneous catalysts can be reused several times without significant loss of their catalytic activity.     

Enhanced catalytic performances of Ag nanoparticles supported on layered double hydroxide for styrene epoxidation

Catalysts or support to catalysts based on layered double hydroxides (LDHs) have been widely investigated in the last few years. Supported Au nanoparticles (NPs), prepared typically by a homogeneous deposition–precipitation technique, have been utilized as catalysts with high activity and selectivity for styrene epoxidation. We herein present a preparation of chemically reduced and cost-saving Ag NPs on the LDH support used as catalyst for styrene epoxidation. A proper reaction condition is optimized, for example, a loading of 2.67 wt% Ag, a conversion temperature of 82 °C, and a conversion time of 8 h. The Ag/LDH catalyst exhibits enhanced reaction selectivity and product yield in comparison with the Au/LDH reported previously. Our results may initiate a facile framework appropriate for noble metallic NPs supported on layered inorganic crystal compounds.     

Synthesis of tetra-aminophthalocyanine/graphite composites by chemical grafting method for styrene oxidation

1,8,15,22-Tetra-aminophthalocyanine/graphite (ZnTAPc/Gr) composites were prepared by chemical grafting method. The property of styrene oxidation in the presence of tert-butyl hydroperoxide (TBHP) as an oxidant was studied. The prepared catalysts were characterized by UV-Vis spectroscopy (UV-Vis), X-ray diffraction (XRD), infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), Raman spectroscopy, UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The obtained ZnTAPc/Gr composites were employed as catalyst for styrene oxidation in presence of tert-butyl hydroperoxide (TBHP) as oxidant. The results showed that styrene was oxidized efficiently in the ZnTAPc/Gr-TBHP system. The enhancement of the catalytic activity of ZnTAPc/Gr composites was investigated in terms of different oxidation conditions. It was found that the optimum oxidation condition was 0.04 g catalyst, 10 h reaction time and reaction temperature of 100°C. Under this condition, the conversion and the selectivity of styrene oxide was up to 73% and 84%.     

丙烯腈-三元乙丙橡胶-苯乙烯接枝共聚物的合成与表征

以正已烷／苯为溶剂，过氧化二苯甲酰（BPO）为引发剂，溶液法合成了丙烯腈－三元乙丙橡胶－苯乙烯接枝共聚物（AES）。用傅立叶变换红外光谱仪对其结构进行表征，用称量法计算接枝参数，并就接枝机理进行了讨论；研究了反应时间、引发剂浓度、EPDM含量及St/AN质量比等条件对接枝反应的影响。结果表明，选择适当的引发剂浓度及EPDM用量可得到具有较高接枝参数的AES。用热重分析法表征了产物的热性能，表明AES耐热性优于ABS。