铈铝柱撑蒙脱土的制备及其负载钴催化剂的费托反应性能

以钠化改型后的内蒙古兴和县蒙脱土为原料, 按照不同的Ce/Al摩尔比合成柱化液,制备铈铝柱撑蒙脱土. 使用XRD, BET, TGA-DTA, ICP和FTIR等方法对柱撑后的蒙脱土进行了表征, 结果表明, 所制备的铈铝柱撑蒙脱土具有高热稳定性, 较大的层间距和高比表面积. 以铈铝柱撑蒙脱土为载体, 使用浸渍法制备了负载钴的柱撑蒙脱土催化剂, 用于费托反应性能评价. 实验结果表明, 交联柱中Ce的引入改变了柱撑蒙托土负载的钴催化剂的性质, 提高了催化活性, 催化剂具有优良的费托合成性能.     

氧化铝柱层状磷酸锡的制备和表征

采用分步交换法制备铝Keggin离子柱层状磷酸锡。产物经500℃焙烧处理,得到层间距为1．35nm的氧化铝柱层状材料(比母体α-SnP的层间距高出0．57nm),而且Al13^7 柱化程度大大优于直接法合成的产物。比较了不同柱化方法的柱化效果,以有机胺水解Alcl3制备的含铝Keggin离子柱化剂的柱化效果明显好于无机碱水解体系.XRD,IR,TG-DTA等分析结果证实有机胺在铝Keggin离子柱化过程中起重要作用。     

新型无机/有机复合柱撑粘土材料的合成与表征

以无机TiCl4／HCl制成的钛基柱撑液和十六烷基三甲基溴化胺(CTAB)为有机改性液,通过控制两种柱撑液的加入顺序以及相对含量,利用蒙脱石粘土矿物层间域的特殊化学反应场所的特性,合成得到三类复合柱撑蒙脱石材料．X射线衍射结果表明,d001晶面由于CTAB与钛基水合离子的相互作用形成粒度不同的柱撑空间而表现为两个峰值．与FT-IR光谱相比,FT-Raman光谱能够更加有效地表征和鉴定复合柱撑粘土的结构差别．采用原土无机柱撑后再有机柱撑,可以合成层间距更大的复合柱撑粘土材料．经热处理后得到锐钛型氧化钛的改性粘土材料,并且可以重新合成得到无机／有机复合柱撑的新型改性粘土材料．这些合成手段为制备新型改性粘土材料应用于环保以及化工等方面提供了借鉴．     

铝柱撑蒙脱石负载纳米金催化剂的结构表征及其CO催化活性研究

以铝柱撑蒙脱石为载体,用沉积沉淀法在其表面负载金属Au后制备了Au负载铝柱撑蒙脱石高效负载型催化剂。以XRD,TEM,XPS等手段对催化剂的结构进行了表征,并研究了铝柱撑蒙脱石负载前后CO催化氧化活性的变化规律。结果证明,Au是以高度分散的状态均匀分布在铝柱撑蒙脱石载体表面,且以Au0和Au3+的混合价态形式存在。CO催化氧化活性表征结果表明,负载后催化剂的催化活性有了显著提高,且其催化活性随着负载量的增加而不断增强,但当负载量增大到一定程度后,其催化活性不再继续增加,且有所下降。     

羟基铝柱撑二硫化钼的制备及其催化加氢性能

 采用单分子层技术将羟基铝聚合物Al7+13阳离子嵌入到二硫化钼板层间,得到层间距为1.488～1.599 nm的柱撑复合材料. X射线粉末衍射等研究表明,羟基铝聚合物Al7+13经60 ℃恒温陈化2 d即可作为稳定的柱撑液使用; 在柱撑反应体系中,较小的Al/Mo摩尔比有利于获得客体物种较均一和结晶度较好的柱撑复合材料. 与原料 2H-MoS2 相比,柱撑二硫化钼的层间距增大,晶粒变小,比表面积增加. 差示扫描量热分析结果表明,柱撑材料具有较好的热稳定性. 选择苯饱和加氢反应为探针,测定了柱撑材料的催化活性. 气相色谱测定结果表明,柱撑二硫化钼的催化性能显著优于未柱撑的 2H-MoS2 和Raney Ni催化剂. 这与柱撑材料比表面积的增大、可能存在的缺陷增多而导致活性位增多以及对氢气的有效吸附增加有关.     

铝柱撑二硫化钼的制备及其催化氧化性质

本文采用单分子层技术将聚合羟基铝簇离子嵌入到二硫化钼板层间，得到层间距为1.481至1.519 nm的柱撑二硫化钼复合材料。XRD、DSC等研究表明，柱化液的滴加浓度越稀、柱撑反应体系中Al∶MoS₂物质的量之比越小越有利于获得层间距较大的柱撑材料。与原料2H-MoS₂相比，柱撑材料的层间距增大，颗粒度变小，比表面积增加。在氧气条件下，对Na₂S的催化氧化实验表明，柱撑材料较原料2H-MoS₂的催化氧化活性提高3～4倍，且光催化活性大于催化活性。这与柱撑材料的比表面积增加所导致催化活性部位的增多，以及光致电子-空穴对的产生有关。     

硅铝柱撑磷酸锆的合成及在大豆油甲酯环氧化反应中的催化性能

基于模板剂导向组装的方法制备了硅铝柱撑磷酸锆.对材料结构进行了表征,分析了硅铝柱撑结构的形成机制.结果表明,材料中铝分别以四面体与八面体的形式嵌入在柱撑结构的内部和层板表面.通过大豆油甲酯的环氧化反应考察了所得硅铝柱撑磷酸锆的催化性能,其催化选择性可达91.7%.反应历程的分析结果表明良好的层板柱撑结构使大分子的反应物能与层间活性位充分接触.硅铝柱撑磷酸锆的酸位特点及催化反应的动力学分析表明,铝源的引入提高了柱撑材料的Lewis酸含量,改善了柱撑磷酸锆对大豆油甲酯环氧化的催化性能.     

羟基铬柱撑二硫化钼的制备及其对苯加氢反应的催化活性

 采用单分子层技术将羟基铬聚合离子[Cr4(OH)6(H2O)10]6+嵌入到二硫化钼板层间,得到层间距为1.319～1.341 nm的柱撑复合材料. X射线粉末衍射表明,羟基铬聚合物溶液经70 ℃恒温下陈化4 d即可作为稳定的柱撑液使用; 在柱撑反应体系中,较小的n(Cr)/n(Mo)比和较低的Cr3+浓度有利于获得结晶度较好的柱撑材料. 与原料2H-MoS2相比,柱撑材料的层间距增大,晶粒变小,比表面积增加并且热稳定性提高. 对催化苯饱和加氢反应表明,柱撑材料Cr-MoS2的催化活性明显优于未柱撑的2H-MoS2和Raney Ni催化剂,且结晶度较好的柱撑材料更具有较高的催化活性和较好的可重复性.     

Al/Fe多核羟基阳离子柱撑膨润土的制备及其对Cr(Ⅵ)的吸附

以云南砚山膨润土为原料,Al~(3+)和Fe~(3+)为柱化剂,采用水热离子交换法,在不同B值(OH-/M~(3+)物质的量之比)和不同Al/Fe条件下制备Al/Fe多核羟基阳离子柱撑膨润土,并用其作为吸附剂吸附Cr(Ⅵ)离子含量为100 mg/L的模拟废水。结果表明,原土的吸附率较低,柱撑后的膨润土有很好吸附效果,吸附率均在90%以上,其中B值为2.5,Al/Fe为1∶10条件下,Cr(Ⅵ)的吸附率达到99.81%。     

介孔锆柱撑钛酸盐材料的制备、表征及光催化性能

采用单分子层剥离-重堆积技术将聚合羟基锆离子嵌入到钛酸盐板层间,制得层间距为1.92~2.01nm的介孔钛酸盐柱撑复合材料。X-射线衍射(XRD)、热重-示差扫描热分析(TG-DSC)、扫描/透射电镜(SEM/HR-TEM)和N2吸附等手段对材料物化性质进行了分析。结果表明,客体锆离子主要以[Zr4(OH)16-n(H2O)8+n]n+(记为Zr4)的形式存在于主体层间域中,且柱撑体系中nZr/nTi比越小,越有利于获得层间距和比表面积较大的柱撑材料。紫外光降解亚甲基蓝实验表明,柱撑材料对亚甲基蓝降解率为钛酸盐主体的3.5倍,这与柱撑形成的介孔结构以及主客体间的电子耦合有关;350℃热处理后材料对亚甲基蓝的降解率进一步提高,说明主客体间形成了更有效的欧姆接触。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.