苯酚加氢制环己酮用高效Pd/MgAl-LDO@Al2O3催化剂的制备及性能研究

环己酮是合成尼龙等材料的重要中间体, 但苯酚直接加氢反应制备环己酮容易生成环己醇而降低收率. 采用原位生长策略制备Pd/MgAl-LDO@Al₂O₃催化剂, 并用于苯酚选择性加氢反应, 获得的催化剂在高底物比条件具有良好的催化性能, 相较于Pd/Al₂O₃催化剂, Pd/MgAl-LDO@Al₂O₃催化剂使苯酚转化率显著增加, 苯酚转化率在97%时环己酮选择性可达88%. 利用X射线衍射(XRD)、程序升温脱附(TPD)、高分辨透射电子显微镜(HRTEM)和X射线光电子能谱(XPS)等手段对催化剂结构进行表征发现在氧化铝上原位生长类水滑石结构能够优化催化剂孔结构并提高活性组分分散度, 且增加了载体表面碱位点的强度, 碱位点的存在影响了苯酚的吸附形式, 从而大幅增加环己酮的选择性. 此外, 当将Ni引入层状结构时, 通过NaBH₄的还原可获得PdNi合金结构. 动力学研究表明, 由于PdNi合金的形成, Pd/NiAl-LDO@Al₂O₃催化剂苯酚加氢反应的能垒低于Pd/MgAl-LDO@Al₂O₃, 同时合金结构导致环己酮选择性的明显降低.     

十聚钨酸季铵盐催化H2O2氧化环己醇为环己酮

研究了十聚钨酸十六烷基三甲基季铵盐H₂O₂体系催化氧化环己醇直接合成环己酮的反应,环己醇的转化率为89.6%～96.4%,环己酮产率为82.4%～89.1%.实验结果表明,该催化剂能促使H₂O₂的活性氧转移,有效地把环己醇氧化为环己酮.     

气质联用法在有机化学实验教学中的应用

从环境保护和产物收率2方面对比本科教学实验中次氯酸钠氧化法和重铬酸钠氧化法制备环己酮的优劣，利用气相色谱质谱联用法对环己醇氧化制备环己酮的产物进行定性定量分析，结果表明次氯酸钠氧化法在产物收率上明显优于重铬酸钠氧化法。不但能让学生了解当有多种方法合成同一化合物时最佳方法的选择，而且使学生的实验操作能力得到提高并对现代物质分析的技术及仪器有一定了解。     

Functionalized CoFe2O4/lamellar mesopore silica anchored to melamine nanocomposite as a novel catalyst for synthesis of 4H-chromenes under mild conditions

In this research, it was displayed an efficient method for the one-pot reaction of cyclohexanone, benzaldehyde and malononitrile for the synthesis of 4H-chromenes by using CoFe₂O₄/lamellar mesopore silica anchored to melamine as a magnetic nanocatalyst. This nanocatalyst was prepared in several steps and discriminated by XRD, FT-IR, SEM, VSM, TGA and BET techniques. The catalyst has a large active base site that has functionalized in both the surface and the pore of nanostructure. The advantages of magnetic nanocatalyst were simple accessible, heterogeneous nanocatalyst, easy work up and reusability. The various derivatives of 4H-chromenes were synthesized in the presence of CoFe₂O₄/lamellar mesopore silica/melamine magnetic nanocatalyst with the excellent yields and appropriate times. The products were identified by the melting point, FT-IR, ¹H NMR, ¹³C NMR and C.H.N techniques.     

Pd(OAc)2-catalyzed orthogonal synthesis of 2-hydroxybenzoates and substituted cyclohexanones from acyclic unsaturated 1,3-carbonyl compounds

A Pd-catalyzed orthogonal synthesis of substituted 2-hydroxybenzoates and substituted cyclohexanones was developed for the first time. The substituted 2-hydroxybenzoates were obtained from acyclic unsaturated 1,3-carbonyl compounds using a combination of catalytic Pd(OAc)₂ and Cu(OAc)₂. On the other hand, the substituted cyclohexanones were produced from similar substrates via catalytic Pd(OAc)₂ and hydrogen chloride. Each transformation was clean, easy to work up, provided the desired compounds in good purities, and did not require column chromatography purification.     

Analysis of femtosecond laser ionization/dissociation of polyatomic molecule C6H10O from one-colour pump-probe measurement

This paper reports that a one-colour fs pump-probe measurement has been carried out for studying photoionization/photodissociation of cyclohexanone (C6H10O) in intense laser field. Two of the fragments from cyclohexanone, C2H3+ and C3H3+ , are studied under 800 nm laser pump-probe and the results obtained show similar time evolutions. It proposes a feasible model for analysing the experimental observations of the one-colour fs pump-probe measurement. The results demonstrate that as an intermediate product, the excited molecular parent ions play a very important role in photionization/photodissociation processes in intense laser field.     

间歇电沉积法制备纳米MnOx/Ti膜电极及其催化氧化环己烷性能

高选择性氧化环己烷（CHA）制备环己酮和环己醇（KA油）具有重要的工业价值和应用前景. 本文提出采用间歇电沉积法制备纳米MnO_x催化剂负载多孔管式钛膜,构建电催化膜反应器（ECMR）催化氧化环己烷制备环己醇和环己酮. 利用场发射扫描电子显微镜（FESEM）、X射线衍射仪（XRD）和电化学工作站等表征手段对催化剂的结构与性能进行表征. 结果表明,间歇电沉积法制备的催化剂为纳米花球状γ-MnO₂. 与基体钛膜相比,MnO_x/Ti膜电极具有更优的电化学性能和传质性能. 此外,以MnO_x/Ti电催化膜为阳极,不锈钢网为阴极构建ECMR. 当环己烷初始浓度30 mmol·L^-1、反应温度30^oC、停留时间34.3 min、电流密度2.3 mA·cm^-2等条件下,ECMR环己烷转化率达25.6%,KA油总选择性高于99%. 同时,ECMR重复使用8次后表现较高催化稳定性.     

Crystal structures of two substituted key intermediates of phenothiazine derivatives

The key intermediates, in the synthesis of phenothiazines, 5-hydroxy-5-methyl 3(phenyl) 2,4-N-dimethylcarbamoyl cyclohexanone, C₁₇H₂₂O₄N₂ (I), and 5-hydroxy-5-methyl 3(2-methylphenyl) 2,4-N-dimethylcarbamoyl cyclohexanone, C₁₈H₂₄O₄N₂ (II), contain essentially substituted cyclohexanone rings in chair conformation with approximately perpendicular oriented phenyl rings. The carbamoyl groups are aligned in opposite directions to facilitate the formation of intramolecular C–HO interaction and O–HO hydrogen bonding. The molecules are linked in helical fashion by an N–HO type intermolecular hydrogen bonding framework. Crystal data: [I], orthorhombic, space group Pbca, a = 9.278(1), b = 19.094(2), c = 19.802(2) Å, V = 3508.0(6) ų, Z = 8 and d = 1.206 Mg m^–3, R = 0.074 (wR = 0.137) for 208 parameters and 1190 observed reflections with I 2 (I); [II], monoclinic, space group P2₁/n, a = 10.523(1), b = 9.005(1), c = 19.771(2) Å, = 94.96(6)°, V = 1866.5(3) ų, Z = 4 and d = 1.183 Mg m^–3, R = 0.062 (wR = 0.131) for 217 parameters and 2276 observed reflections with I 2 (I).     

Decyclization of chiorocyclohexanone hydroperoxides under the action of ferrous salts

The decomposition of 2-chloro-, 2,2-dichloro-, and 2,6-dichloro-substituted cyclohexanone hydroperoxides on treatment with ferrous chloride and sulfate to give chloro-substituted aliphatic acids was investigated. A method for the synthesis of 2,6,6-trichlorohexanoic and 2,6,7,11-tetrachlorododecane-1,12-dioic acids was elaborated.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 143–146, January, 1996.