具有十二元环空旷骨架的Mn3Al6(PO4)12·4tren·11H2O的水热合成与表征

自从1982年美国联合碳化公司(U.C.C.)开发出系列磷酸铝分子筛(AlPO4-n,n代表不同的骨架类型)[1]以来,新型微孔结构磷酸铝的开发一直吸引着人们的广泛关注[2].与此同时,杂原子磷酸铝分子筛的研究受到了人们的高度重视,许多元素(Fe,Mn,Co,Zn等)可以作为杂原子进入磷酸铝的分子筛骨架[3～5].其中,含有特殊催化活性的过渡金属离子Mn的磷酸铝备受关注[6,7].1999年,徐耀华等[8]合成出具有新颖三维开放骨架的磷酸铝Al9(PO4)12(C24H91N16)·17H2O.最近,Beitone等[9,10]研究了Zn和Fe元素在此骨架中的取代情况.本文中,我们首次将Mn元素引入…     

异金属铜-氧MAZ分子筛催化甲烷部分氧化反应DFT研究

已有研究证明了 Cu-MAZ分子筛催化甲烷部分氧化的优异性且实验表征得出其活性结构含有三核铜结构.为进一步提高部分氧化活性,采用MAZ分子筛作为载体体系,用于[Cu3(μ-O)3]2+结构,分别掺杂Pd、Pt、Fe、Co、Ni、Au和Ag,构建[Cu2MO3]2+异金属活性位.通过密度泛函理论(DFT)研究不同金属对C...     

C4烃在FAU、BEA、LTL型分子筛中吸附的蒙特卡罗研究

应用蒙特卡罗(MC)模拟方法研究了1,3-丁二烯、1-丁烯、正丁烷三种C4烃在FAU、BEA、LTL三种分子筛中的吸附行为. 模拟分别得到了298 K时这些C4烃的纯组分在分子筛中的吸附等温线、吸附质分布和吸附热. 结果表明, 在饱和吸附状态下这些C4烃在FAU分子筛中的吸附量最大, 在BEA分子筛中的吸附量居中, 在LTL分子筛中的吸附量最少. 对于同一种分子筛来说, 正丁烷在其中的等量吸附热最大, 1-丁烯居中, 1,3-丁二烯最小. 对于同一种C4烃来说, 它在LTL分子筛中的吸附热与在BEA分子筛中的吸附热相近, 并且高于在FAU分子筛中的吸附热. 还模拟了543 K、2.0 MPa时这些C4烃的三元混合组分在分子筛中的吸附, 发现正丁烷的吸附量占的比例最大, 1-丁烯居中, 1,3-丁二烯最少.     

2D层状焦磷酸锰髤[NH_4]_2[Mn_3(P_2O_7)_2(H_2O)_2]的结构和磁性研究

由于具有开放骨架的金属磷酸盐在催化、吸附、主客体组装以及光学、磁学等方面的应用[1~3],因此合成具有开放骨架的金属磷酸盐一直吸引着人们的广泛关注。自从1982年美国联合碳化公司(U.C.C.)开发出系列磷酸铝分子筛AlPO4鄄n[4]以来,大量具有开放骨架的金属磷酸盐(金属=Ga,In,F     

一种具有最大空穴的新分子筛

最近,欧洲的研究人员 C.Baerlocher 等人合成了一种新的分子筛,其超笼的宽度为30(?),大大超过目前所知的其它任何一种笼的尺寸[Nature,352,     

杂原子Y分子筛的二次合成及其吸附脱硫性能(Ⅱ)

Breck等[1]发表了用NH4SiF6溶液对分子筛进行脱铝补硅的二次合成方法,提高了骨架的硅铝比,从而改变了分子筛的热稳定性、酸性以及催化活性.作为该方法的扩展,已有将Ti、Te、Cr、Zr、Ga等元素引入分子筛骨架的报道[2～4].目前,已经有杂原子分子筛应用到工业生产中,但采用杂原子分子筛吸附脱硫的报道还较少.前文[5]采用液-固相同晶取代反应制备了骨架含Ga的Y型分子筛,并对其吸附脱硫性能进行了初步研究.本研究进一步对[Ga]AlY的吸附脱硫机理、再生性能等方面进行了深入研究.……     

苯及苯磺酸基官能化的中孔分子筛的合成及催化应用

近年来 ,通过对介孔分子筛 (如 MCM,HMS,MSU-X)结构及组成的化学“裁剪”,制备具有特定结构和表面性质的催化材料成为该领域的研究热点之一 [1～ 5] .许多文献报道了 MCM-4 1的有机官能化中孔材料的制备技术 [5～ 8] ,并将其应用于有机合成反应 ,取得了较好的结果 [7,8] .其中 MSU-X介孔分子筛结构具有三维排列“Worm-like”孔道特征 ,有利于物料传输 ;相对于 MCM-4 1分子筛在合成方面具有以中性表面活性剂作模板剂且模板剂容易去除等诸多优点[9] .本文采用非离子表面活性剂 C11— 15H2 3— 31(CH2 CH2 O) 9H(AEO9)为模板剂 ,…     

六方沸石分子筛催化剂用于异丁烷与丁烯的烷基化

异构烷烃与烯烃的烷基化是炼油装置制备高辛烷值汽油添加剂的重要途径.目前传统工艺仍使用矿物酸如硫酸或氢氟酸作催化剂,由于该工艺存在着产物分离困难、设备腐蚀严重及环境污染问题,从60年代起国内外开始致力于新型固体酸催化剂的研究与开发工作,已报道的有离子交换树脂[1]、分子筛催化剂[2]及SO=4/MxOy型催化剂[3]等,在分子筛催化剂中已报道的有立方沸石[4]β-分子筛[5]、ZSM系列[5]、分子筛[5]、蒙脱石[5]及MCM-22[6]等,这些催化剂的共性是催化活性较高,但失活较快.目前对分子筛催化剂的研究主要集中在改进的立方沸石体系,而六方沸石催化剂催化异丁烷与丁烯烷基化反应尚未见报道.     

碱改性ZSM-5分子筛及脱硫性能的研究

用4 mol·L-1Na2CO3溶液处理ZSM-5分子筛[HZSM-5(C)],处理后的分子筛采用n(TPAOH)∶n(Si O2)=0.2∶1的TPAOH溶液进行二次晶化[HZSM-5(C-T)]。制备了Ni-Mo/HZSM-5(原粉)、Ni-Mo/HZSM-5(C)和Ni-Mo/HZSM-5(C-T)催化剂。在小型连续固定床反应器上,考察了Ni-Mo/HZSM-5,Ni-Mo/HZSM-5(C)和Ni-Mo/HZSM-5(C-T)催化剂的硫醚化反应性能。结果表明:Na2CO3处理形成了微-介孔多级孔HZSM-5分子筛,提高了硫醇转化率;TPAOH二次晶化,修复了分子筛的孔道,增加了介孔的数量,进一步提高了硫醇的转化率。考察了TPAOH二次晶化前后,HZSM-5分子筛的热稳定性和水热稳定性。结果表明:Na2CO3处理降低了HZSM-5分子筛的热稳定性和水热稳定性,而TPAOH二次晶化,提高了HZSM-5分子筛的热稳定性和水热稳定性。     

杂原子取代型磷酸铝分子筛上丁烯异构化反应

采用水热法合成了Si、Zr杂原子取代的磷酸铝分子筛（APO-11）.研究发现,它们(SAPO-11、ZAPO-11)与APO-11分子筛骨架结构相同（AEL型）；三者表面形貌不同,SAPO-11与APO-11分子筛同为球形颗粒,而ZAPO-11则为棒状晶粒.杂原子的取代能改变APO-11分子筛的酸性质以及微孔分布.反应评价显示,异构化活性SAPO-11>> ZAPO-11 > APO-11；其中SAPO-11分子筛,当Si/Al=0.15时,异构化性能最佳.异构化反应的因子（时间、分压、温度）系统考察发现,主要副产物C3、C5＋与i-C4=的浓度呈现不同的变化趋势,从而证实丁烯选择性异构是通过单分子机理实现的,C3、C5＋是通过双分子历程生成的.     

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%.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.