镱钼钒磷四元杂多化合物催化苯酚羟化分应的研究

合成了具有Keggin结构镱钼钒磷杂多化合物,用IR,UV,XRD,ICP等手段对其结构进行了表征,并研究了该杂多化合物对苯酚过氧化氢羟化反应的催化活性。实验结果表明：以甲醇为溶剂,用镱钼钒磷杂多化合物为催化剂,当（n(phOH):n(H2O2)=1:2,反应体系的pH=5.0,反应时间4h,苯酚转化率为41．66％,对苯二酚产率可达到40．24％。     

(NH_4)_(11)Gd[Gd_4Mo_(29)O_(100)(H_2O)_(16)]·33H_2O杂多化合物

苯二酚 ( DHB)是一种重要的化工原料 ,由苯酚过氧化氢羟化制苯二酚的生产路线 ,反应工艺简单 ,不污染环境 ,被认为是 2 1世纪最有价值、最有前途的工艺路线之一 .其关键在于研制高活性、高选择性的催化剂以提高产率使之实现工业化 .迄今为止 ,用于催化苯酚过氧化氢羟化制苯二酚的杂多化合物尚仅限于具有 Dawson结构的钼钒磷、钨钒磷杂多化合物[1,2 ] .本文设计合成了含稀土元素钆的二元杂多化合物 ( NH4 ) 11Gd[Gd4 Mo2 9O10 0 ( H2 O) 16]· 33H2 O,添加适量 V2 O5后应用于苯酚过氧化氢羟化制苯二酚反应 ,取得较好的催化效果 .称取 …     

Co4HP2Mo15V3O62的合成及其催化乙苯氧化反应性能

合成了一系列Dawson型磷钼钒钴杂多酸盐Co<,n> H<,9-2n>P<,2>Mo<,15>V<,3>O<,62>(n=1-4),用傅立叶变换红外光谱表征了磷钼钒钴的结构.以乙苯为原料、H<,2>O<,2>为氧化剂、磷钼钒钴杂多酸盐为催化剂催化氧化乙苯制备苯乙酮.考察了催化剂种类及用量、助剂用量、H<,2>O<,2...     

Dawson结构钼钒磷杂多化合物对苯酚过氧化氢羟化作用的研究

Ｄａｗｓｏｎ结构钼钒磷杂多化合物对苯酚过氧化氢羟化作用的研究于剑锋，杨宇，吴通好，孙家锺（吉林大学化学系理论化学研究所，长春，１３００２３）关键词Ｄａｗｓｏｎ结构钼钒磷杂多化合物，苯酚羟化，过氧化氢苯二酚（ＤＢＨ）是重要的化工原料．由芳香化合物羟化制...     

纳米磷钼钒杂多酸盐催化苯羟基化合成苯酚

纳米磷钼钒杂多酸盐催化苯羟基化合成苯酚;苯; 羟基化; 苯酚; 纳米杂多化合物     

Dawson结构磷钼钒酸铯催化H_2O_2氧化苯合成苯酚

采用乙醚反萃取方法合成了Dawson结构磷钼钒酸H8P2Mo16V2O62,进而与碳酸铯反应得到Dawson结构磷钼钒酸铯催化剂CsnH8-nP2Mo16V2O62(n=1-5),利用X射线粉末衍射(XRD)、红外(FTIR)以及SEM等对催化剂进行分析,并以H2O2为氧化剂,评价其在苯液相氧化直接羟基化合成苯酚反应中的催化性能,系统的研究了反应时间、催化剂用量、H2O2用量、反应溶剂等反应条件对催化反应的影响。结果表明,合成Cs3H5P2Mo16V2O62在催化反应中表现出优良的催化活性,优化条件下,苯酚收率达到31.0%;催化剂回收方便,可多次重复使用,在反应过程中,催化剂的Dawson结构没有明显变化。     

钒钼杂多酸盐相转移催化环戊烯氧化制备戊二醛

设计合成了一系列含高价态钼、钒等金属的杂多酸类相转移催化剂,用于催化环戊烯(CPE)氧化制备戊二醛的反应,筛选出催化活性最优的咪唑基钼钒酸盐催化剂[C₄H₉N₂C₃H₃(CH₃)]₅VMo₇O₂₆,并对溶剂种类、H₂O₂用量、催化剂用量、反应温度、时间等进行了条件优化.在优化的反应条件[V(乙酸乙酯)∶V(水)=4∶1,n(Cat.)∶n(H₂O₂)∶n(CPE)=1∶170∶41.6,50℃,6 h]下,得到了88.7%的环戊烯转化率和62.1%的戊二醛选择性,并且催化剂在经过7次循环使用后仍能保持较高的催化活性.     

(NH4)15[Ce(PMO9V2O39)2]·5H2O杂多配合物合成及在苯酚羟化反应中的催化活性

合成了(NH4)15[Ce(PMo9V2O39)2]@5H2O杂多化合物,并用ICP,IR,UV,XRD等手段对其结构进行表征,结果表明该化合物是具有Keggin结构的杂多化合物.考察了该杂多化合物对苯酚过氧化氢羟化反应的催化活性,研究了反应介质、反应温度、反应时间、反应体系pH及molрhoH:molH2O2,对催化活性的影响.实验结果表明:以甲醇为溶剂,用标题化合物作催化剂,当molрhoH:molH2O2,=2:5.反应体系pH为5左右,反应温度70℃,反应时间4h时,苯酚转化率为43.30%,对苯二酚产率可达42.20%.     

Keggin结构稀土钼钒磷四元杂多配合物的合成、表征及苯酚羟化制苯二酚的催化活性

合成了5种通式为(NH₄)₁₅[RE(PMo₉V₂O₃₉)₂]·xH₂O(RE=La³⁺,Ce³⁺,Gd³⁺,Y³⁺,Yb³⁺)的稀土钼钒磷四元杂多配合物,并用IR,UV,XRD,ICP,TG-DTA和CV等手段对其结构和性能进行了表征.催化活性实验表明,标题化合物对苯酚过氧化氢羟化制苯二酚反应有良好的催化活性.     

9—钼—3钒硅酸钾的合成与表征

钼钒硅杂多化合物作为氧化还原型催化剂应用于某些有机合成反应已引起化学工作者的关注,其合成与分离均有一定的难度,一钒及二钒取代的钼钒硅杂多化合物已有文献报道,但三钒取代的钼钒硅杂多化合物尚未见报道,本文采用正交设计方法,成功地合成了标题杂多化合物,并通过IR、UV、TG-DTA、~(51)V NMR和ESR等测试手段进行了表征。     

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.     

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.     

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.     

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.