磷酸硼固体酸催化合成邻苯二甲酸二乙酯的性能研究

以邻苯二甲酸酐和无水乙醇为原料,固体磷酸硼为催化剂,在醇酐比为4：1,催化剂用量为苯酐用量的20．3％,反应时间8h,反应温度80℃条件下合成邻苯二甲酸二乙酯（DEP）,探讨了影响催化剂催化效果的各个因素。实验表明,催化剂最佳的制备条件为：磷酸、硼酸和硫酸的摩尔比为1：1：1,焙烧温度为300℃,焙烧时间为3．5h。DEP最高产率可达75％。     

固体酸催化合成邻苯二甲酸二戊酯的研究

以苯酐和正戊醇为原料,采用自制的固体酸SO4^2-／SiO2、SO4^2-／Fe2O3、SO4^2-／SnO2及SO4^2-／TiO2作为催化剂合成邻苯二甲酸二戊酯（DAP）,分别考察固体酸催化剂的种类、固体酸催化剂的用量、醇酐比、反应时间等因素对合成DAP产率的影响。实验结果表明,其优化的工艺操作条件为：苯酐0．1mol,固体酸催化剂SO4^2-／SiO2 1．7g,醇酐比2．4：1,带水剂二甲苯20mL,反应时间3．5h,其产品收率达91．3％以上。SO4^2-／SnO2作为该反应的催化剂具有催化活性高、寿命长、可多次重复使用、产物易纯化分离且产品色泽浅等优点,可望代替传统的浓硫酸作催化剂应用于DAP的合成。     

用新方法催化合成6-乙酰基-1-甲基环己烯

室温下用HY沸石取代传统催化剂通过1-甲基环己烯与乙酐的酰基化反应合成了6-乙酰基-1-甲基环己烯，考察了HY沸石的SiO2／Al2O2摩尔比、用量和活化时间以及反应时间对该酰化反应的影响．当1-甲基环己烯／乙酐／HY沸石(SiO2／Al2O3摩尔比=29)=1mmol／10mmol／0．200g、反应温度25℃、反应时间3h时，所得酰化产品的产率为60％，HY沸石能够回收和重新使用，显示出与新鲜催化剂几乎相同的催化活性．     

糠酸加氢负载型催化剂的制备及催化性能

选用不同的贵金属钌、铑、钯、铂，不同的金属担载量，不同的催化剂载体氧化硅、活性炭（AC）、γ-三氧化二铝等，制备了多种负载型催化剂，采用连续操作的固定床微型反应器评价了它们的糠酸加氢催化性能．研究表明，金属钯的性价比最好，钯的最佳担载量为0．8％，最适宜的催化剂载体是γ-三氧化二铝．催化剂0．8％Pd／γ-Al2O3，具有良好的催化活性和选择性．优化了该催化剂上糠酸加氢的反应条件，结果表明，在1．0MPa、150oC、氢气空速2000h^-1、糠酸的乙酸乙酯溶液的空速4．0h^-1的条件下，糠酸转化率达100％，四氢糠酸选择性为99．0％．     

Br(o)nsted酸性离子液体催化合成阿司匹林

用Brcnsted酸性离子液体[Hmim]BF4、[bmim]HSO4和[bmim]H2PO4代替浓H2SO4为催化剂催化乙酸酐对水杨酸的乙酰化，合成阿司匹林。考察了反应温度、反应时间、催化剂用量、酐／醇摩尔比对水杨酸酰化反应产率的影响和离子液体的重复使用性能。选择了最佳反应条件，以[bmim]H2PO4作为催化剂，催化剂用量为0．28g（1．18×10^-3mol），水杨酸2．762g（0．02mol），乙酸酐4．083g（0．04mol），n（酐）：n（醇）=2：1，反应时间30min，反应温度70℃，产率最高达63．43％，并且[bmim]H2PO4溶于水后通过过滤和旋蒸脱水，重复使用3次，产率无明显变化。     

固体铌酸催化下甲苯的硝化

在不同焙烧温度下制备了一系列固体铌酸催化剂。测定了固体铌酸催化剂的比表面积、表面酸强度及表面酸量。研究了催化剂焙烧温度、硝化反应时间、硝化反应温度、有无醋酐存在、硝酸浓度、催化剂的重复使用等因素对甲苯硝化反应影响。实验结果表明,当反应温度为40℃,反应时间为60 min时,以CCl4为溶剂,以质量分数为95%的硝酸为硝化剂,在醋酐存在条件下,以经300℃焙烧3 h后的铌酸作为催化剂,甲苯硝化产物中异构体的邻对比达1.26,较硝硫混酸的1.67显著降低,产物得率达99.3%。且该催化剂循环使用5次,催化活性基本不变,是一种极具应用前景的绿色硝化反应催化剂。     

固体酸ZrO2-Ce2O3／SO4^2-催化合成丙二酸二丁酯

以含铈固体超强酸ZrO2-Ce2O3／SO4^2-为催化剂，丙二酸和正丁醇为原料合成了丙二酸二丁酯。最佳反应条件为：催化剂活化温度500℃，丙二酸100mmol，n(酸)：n(醇)=1．0：2．5，催化剂用量1g,反应时间2h，酯化率达95．8％。结果表明，加入铈有助于提高固体超强酸的使用寿命。     

取代氨乙基膦酸的简便合成

以2-氯乙基膦酸和胺为原料，经一步反应合成了3种取代氨乙基膦酸，合成工艺条件为：2-氯乙基膦酸200mmol，n(2-氯乙基膦酸)：n(胺)=1：1．1，反应温度18℃，反应时间120h，pH8～10，KI作催化剂，收率78．2％～91．0％。用元素分析，IR和^1H NMR表征了标题化合物。     

铁系固体酸催化剂的制备及催化合成水杨酸酯

制备了铁系固体酸催化剂(Ⅰ)并将其用于催化合成水杨酸酯，优化了反应条件：当Ⅰ用量为投料质量的6．1％，mol酸：mol醇=1：4，适当提高反应温度，合成水杨酸戊酯的反应时间可缩短至3h，产率达91．3％。合成其它水杨酸酯时也取得很高的产率。通过对比，Ⅰ的催化酯化能力优于Fe2O3／SO4^2-固体超强酸催化剂，套用6次后催化性能基本保持不变。     

复合型固体超强酸SO4^2-／SnO2-TiO2催化合成乙酸松油酯的研究

采用溶胶-凝胶法制备了新型复合固体超强酸SO4^2-／SnO2-TiO2，通过XRD和IR对其结构进行了表征。以该固体酸为催化剂、松油醇和乙酸酐为原料合成乙酸松油酯，考察了影响反应的因素。结果表明：反应温度40-50℃、催化剂用量1．8-—2．2％、醇酐摩尔比1：1．6、反应时间4-5h是最适宜的反应条件，其松油醇转化率达到98％以上，产物中乙酸松油酯含量为88％。与普通单氧化物固体酸比较，该复合型固体酸有更高的催化活性和选择性。     

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%.     

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.     

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.     

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.