V@CN催化的芳烃的氧气羟基化反应（英文）

制备了V@CN催化剂,并用于氧气条件下芳烃的直接羟基化反应.结果表明,在V@CN催化剂作用下,带有不同吸电子基团(CN,NO2,COOH,CF3和COCH3)的芳烃均可被O2氧化得到相应的酚,产率中等.含有卤素(F,Cl和Br)的芳烃也可在该催化体系作用下转化为相应的酚.     

改性活性炭催化羟基的四氢吡喃化保护及脱保护反应研究

以浓硫酸改性的活性炭为催化剂,催化二氢吡喃对醇(酚)羟基的保护,使其形成相应的四氢吡喃醚(2):2在催化剂作用下能顺利的脱除保护基团.     

Mo和Ni改性的HZSM-5催化剂对煤热解焦油的改质

考察了Mo和Ni改性的HZSM-5催化剂对煤热解焦油的改质性能,分析了催化改质前后焦油中轻质芳烃分布的变化规律。结果表明,经HZSM-5催化剂褐煤(XM)热解轻质芳烃总量的增加率为220%,这与煤热解产物在HZSM-5催化剂中发生烯烃和烷烃的芳构化以及酚羟基脱除等作用有关。负载活性金属Mo和Ni后,可以有效促进轻质芳烃的生成;Ni对焦油中带脂肪侧链化合物具有更强的裂解作用,而Mo则有利于带侧链化合物如甲苯和二甲苯的形成。焦煤(FX)热解过程中轻质芳烃的释放量分别是XM煤和年轻烟煤(PS)的2.2和2.4倍。经催化改质后,XM煤产物中轻质芳烃产率明显大于PS煤,并接近FX煤;这主要是因为XM煤结构中含有较多的含氧官能团和脂肪结构,在HZSM-5作用下可催化形成轻质芳烃。     

磷改性Cr2O3/Al2O3催化4-乙基酚转化制轻质芳烃

以烷基酚转化为轻质芳烃(苯和甲苯)为目标,制备了Cr_2O_3/Al_2O_3催化剂,并以4-乙基酚为模型化合物研究了其加氢反应性能。体积空速、氢油比、反应压力和温度升高时,脱烷基率、芳烃总选择性、轻质芳烃选择性呈先增大后减小的趋势,反应温度对转化率影响较大。以不同浓度磷酸对Cr_2O_3/Al_2O_3进行改性,随着磷酸用量的增大,催化剂酸量总体增大,主要是弱酸和中强酸,酸强度先增加后降低,磷酸用量较高时,弱酸增加幅度较大。与未改性相比,质量分数8%磷酸改性Cr_2O_3/Al_2O_3上4-乙基酚转化率99.5%,脱烷基率提升9.4%,达74.4%,轻质芳烃选择性提高4.0%,达到57.0%,以较高选择性实现了转化制轻质芳烃,同时,芳烃总选择性高达80.4%,较高程度保持了芳环不被破坏。提出了Cr_2O_3/Al_2O_3上4-乙基酚加氢反应的路径并对反应机理进行了研究。     

铬催化剂的组成对于庚烷芳烃化反应的影响

在不同组成的催化剂(K_2O-Cr_2O_3-Al_2O_3)上进行了庚烷芳烃化反应,研究了催化剂中钾、铬浓度的改变对于芳烃化活性和碳沉积性能的影响.铬浓度增加时,芳烃化活性和碳沉积性能平行增加,两者比值保持不变.催化剂中加入氧化钾后,芳烃化活性显著增加而碳沉积性能则显著降低.因此,氧化钾是铬铝催化剂的一个具有良好选择性的助催化剂.     

新型丹皮酚肟酯的高效合成

以丹皮酚为原料,与乙酸在N,N-二甲基乙酰胺(DMAc)和SOCl₂作用下反应制得乙酰丹皮酚酯（1）; 1中酮羰基与盐酸羟胺反应生成相应的丹皮酚肟（2）;在DMAc和CH₂Cl₂体系中,取代羧酸(3a～3l)与SOCl₂反应生成酰氯后随即与2反应合成了系列新型丹皮酚肟酯(4a～4l),产率80.9%～95.5%,其结构经¹H NMR、¹³C NMR、IR和MS表征。以苯甲酰丹皮酚肟酯（4a）的合成为例,对反应条件进了优化。最优反应条件为：以DMAc(2 mL)为催化剂,酰氯化反应时间为20 min,酯化反应时间为3 h,产率95.1%。并对DMAc促进丹皮酚肟酯合成反应的可能机理进行了探讨。     

NiMoP/γ-Al_2O_3催化剂的煤焦油加氢性能研究

采用分步浸渍法制备了一系列NiMoP/γ-Al_2O_3催化剂,并用电感耦合等离子体光谱、N_2吸附脱附、透射电镜、H_2程序升温还原等技术对NiMoP/γ-Al_2O_3催化剂进行了表征。在固定床反应器中,进行了模型化合物的加氢实验,确定了催化剂活性组分Ni的最佳含量(4%,质量分数),将最佳Ni含量的催化剂用于实际的煤焦油加氢研究,并对比分析了酚油的切除对加氢效果的影响,结果表明,酚油的切除可以促进S、N原子的脱除以及芳烃的饱和。     

FeCl3催化羰基化合物与芳烃的还原Friedel-Crafts烷基化反应

在二甲基氯硅烷作用下, FeCl3能催化羰基化合物(醛、酮)与芳烃及噻酚的还原Friedel-Crafts烷基化反应, 在温和的条件下一步实现羰基化合物的还原和C—C键的构造.     

离子液体水溶液中2-甲基氮杂芳烃苄位C(sp~3)—H官能化反应

以中性离子液体水溶液为反应介质,无需催化剂的条件下,通过2-甲基氮杂芳烃苄位C(sp~3)—H与缺电子烯烃之间的加成反应,以良好产率合成了一系列氮杂芳烃衍生物.该方法操作简单,条件温和,不仅拓展了离子液体在氮杂芳烃的C(sp~3)—H官能化反应中的应用,对绿色化学的发展也有积极的推动作用.     

杯芳烃衍生物的合成3

通过杯[4]芳烃的酚羟基的烷基化和苯环上的乙酰化制备了一系列的新的对乙酰基杯[4]芳烃烷基醚,烷基分别是n-C~4H~9(4a)、n-C~8H~1~7(4b)、n-C~1~2H~2~5(4c)和n-C~1~6H~3~3(4d)。核磁共振研究表明这些新的杯芳烃都是锥形(cone)构象。     

An efficient, catalytic, aerobic, oxidative iodination of arenes using the H5PV2Mo10O40 polyoxometalate as catalyst

Iodination of arenes was carried out by reacting 1 equiv of arene substrate with 0.5 equiv of iodine under an oxygen atmosphere with H5PV2Mo10O40 as oxidation catalyst. The synthesis is an inherently waste-free method for the preparation of iodoarenes.     

Iron‐Catalyzed Aminative Cyclization/Intermolecular Homolytic Aromatic Substitution Using Oxime Esters and Simple Arenes

Intermolecular C?H alkylation of simple arenes in the presence of an iron catalyst has been achieved in a cascade manner with an aminative cyclization triggered by N?O bond cleavage of an alkene‐tethered oxime ester. Various arenes, including electron‐rich and electron‐poor arenes, and heteroarenes can be employed in the reaction system. Regioselectivity and radical trapping experiments support the involvement of alkyl radical species, which undergo a homolytic aromatic substitution (HAS) to afford the arylation products.     

Surface Modification of a Supported Pt Catalyst Using Ionic Liquids for Selective Hydrodeoxygenation of Phenols into Arenes under Mild Conditions

The selective and efficient removal of oxygenated groups from lignin-derived phenols is a critical challenge to utilize lignin as a source for renewable aromatic chemicals. This report describes how surface modification of a zeolite-supported Pt catalyst using ionic liquids (ILs) remarkably increases selectivity for the hydrodeoxygenation (HDO) of phenols into arenes under mild reaction conditions using atmospheric pressure H₂. Unmodified Pt/H-ZSM-5 converts phenols into aliphatic species as the major products along with a slight amount of arenes (10 % selectivity). In contrast, the catalyst modified with an IL, 1-butyl-3-methylimidazolium triflate, keeps up to 76 % selectivity for arenes even at a nearly complete conversion of phenols. The IL on the surface of Pt catalyst may offer the adsorption of phenols in an edge-to-face manner onto the surface, thus accelerating the HDO without the ring hydrogenation.     

Activation of C-H bonds of arenes: selectivity and reactivity in bis(pyridyl) platinum(II) complexes

The reaction of [PtMe2(NN)] and B(C6F5)3/H2O in CF3CH2OH with arenes Ar-H gives [PtAr{HOB(C6F5)3}(LL)] if the bis(pyridyl) ligand NN forms a six-membered, but not five-membered, chelate ring; methyl-substituted arenes give selectivity for metalation of meta > para > ortho, but methoxy-substituted arenes give ortho > meta, para.     

C−O Activation by a Rhodium Bis(N‐Heterocyclic Carbene) Catalyst: Aryl Carbamates as Arylating Reagents in Directed C−H Arylation

Despite recent progress in the catalytic transformation of inert phenol derivatives as alternatives to aryl halides and triflates, attempts at the cross‐coupling of inert phenol derivatives with the C−H bonds of arenes have met with limited success. Herein, we report the rhodium‐catalyzed cross‐coupling of aryl carbamates with arenes bearing a convertible directing group. The key to success is the use of an in situ generated rhodium bis(N‐heterocyclic carbene) species as the catalyst, which can promote activation of the inert C(sp²)−O bond in aryl carbamates.     

Selective Halogen-Lithium Exchange Reaction of Bromine-Substituted 25,26,27,28-Tetrapropoxycalix[4]arene

Methods are described for the selective bromine-lithium exchange reaction of bromine-substituted calix[4]arenes with either n-BuLi or t-BuLi in THF. Quenching of the lithiated calix[4]arenes with MeOH, D(2)O, CH(3)SSCH(3), B(OCH(3))(3), DMF, or CO(2) as electrophiles resulted in 5-monosubstituted, 5,17-disubstituted, or 5,11,17,23-tetrasubstituted calix[4]arenes with H, D, SCH(3), B(OH)(2), CHO, or COOH functionalities.     

Friedel-Crafts amidoalkylation via thermolysis and oxidative photocatalysis

Friedel-Crafts amidoalkylation was achieved by oxidation of dialkylamides using persulfate (S(2)O(8)(2-)) in the presence of the visible light catalyst, Ru(bpy)(3)Cl(2), at room temperature, via a reactive N-acyliminium intermediate. Alternatively, mild heating of the dialkylamides and persulfate afforded a metal and Lewis acid-free Friedel-Crafts amidoalkylation. Alcohols and electron-rich arenes served as effective nucleophiles, forming new C-O or C-C bonds. In general, photocatalysis provided higher yields and better selectivities.     

Double-coupling of dibromo arenes with aryltriolborates for synthesis of diaryl-substituted planar frameworks

A new method for simple and practical synthesis of diaryl-substituted arenes using potassium aryltriolborates was developed. Double-cross-coupling of dibromo arenes with aryltriolborates was carried out in the presence of a palladium catalyst, such as Pd(OAc)₂, Pd(PPh₃)₄ or Pd(OAc)₂/BIPHEP. The use of CuCl (40 mol %) with a palladium catalyst was found to be highly effective to give diaryl-substituted aromatic compounds in good yields.     

Chemo‐ and Regioselective Hydrogenolysis of Diaryl Ether C−O Bonds by a Robust Heterogeneous Ni/C Catalyst: Applications to the Cleavage of Complex Lignin‐Related Fragments

We report the chemo‐ and regioselective hydrogenolysis of the C?O bonds in di‐ortho‐substituted diaryl ethers under the catalysis of a supported nickel catalyst. The catalyst comprises heterogeneous nickel particles supported on activated carbon and furnishes arenes and phenols in high yields without hydrogenation. The high thermal stability of the embedded metal particles allows C?O bond cleavage to occur in highly substituted diaryl ether units akin to those in lignin. Preliminary mechanistic experiments show that this catalyst undergoes sintering less readily than previously reported catalyst particles that form from a solution of [Ni(cod)₂].     

Catalytic hydroarylation of alkynes with arenes in the presence of FeCl3 and AgOTf

Hydroarylation of propiolic acids with various arenes in TFA proceeded efficiently in the presence of FeCl₃/AgOTf catalyst system. In the case of electron-rich arenes, the iron-catalyzed hydroarylation gave cinnamic acids in moderate to high yields. The hydroarylation of phenylacetylene was observed but the catalyst was not effective under the same conditions.