金属化合物催化的1,1′-联二萘酚-4,4′-二乙酸酯和二(2-乙基己醇)碳酸酯的酯交换

芳香族聚碳酸酯性能优良,其中双酚-A型聚碳酸酯是应用广泛的工程塑料,通常采用光气法或酯交换法来制备,但芳香双羟基化合物与二烷基碳酸酯的酯交换反应速度十分缓慢,需要使用催化剂,且反应温度较高,反应过程伴随着复杂的副反应。本文用金属化合物作催化剂进行1,1′-联二萘酚-4,4′-二乙酸酯和二(2-乙基己醇)碳酸酯的酯交换反应,评价了不同金     

酵母脂肪酶催化拆分外消旋2-甲基-1-丁醇

近年来,水相中酶催化拆分外消旋酯制备具有光学活性的手性酸或醇,其酶在非水体系的研究取得了重要进展,已发展到用含有微水或几乎无水的有机溶剂取代最初的水相,这样既可避免水参与有关的副反应,又有利于酶的回收。而且酶在某些有机溶剂中比在水中稳定,不会由于微生物污染而使酶失活。脂肪酶能够催化酯的     

固定化嗜热酯酶催化拆分(R,S)-2-甲基-1-丁醇

利用帆布固定化嗜热酯酶APE1547(3)在非水介质中催化转酯化反应进行酶促拆分(R,S)-2-甲基-1-丁醇制备(S)-2-甲基-1-丁醇(4).初步探讨了溶剂、酰基供体、温度及底物配比对3的催化活力(EA3)′与4对映选择性比率(E4)的影响.在最佳拆分条件下,EA3 =0.53 μmol·min-1·mg-1,E4=15.4.3套用8次后仍然保持较高的催化活性.     

2-乙基己基膦酸单2-乙基己酯铜(Ⅱ)萃合物的ESR谱和电子结构

有机酸性膦(磷)酸酯与二价铜离子的萃合物研究已有报导。文献[1]对该萃合物的结构做了初步讨论,认为由于在正庚烷溶剂中铜萃合物的吸收光谱呈一宽的吸收带,最大吸收峰位置在13600cm~(-1)处,难以推断该萃合物是四面体还是平面正方形结构。本文在291和77K下测定了萃合物的ESR谱,并用量子化学的CNDO/2方法对该萃合物的电子结构作了进一步研究。     

N-乙基-1，10-菲罗啉-2-甲胺镍(Ⅱ)配合物的合成、晶体结构及性质研究(英)

A novel ligand N-ethyl-1,10-phenanthroline-2-methanamine and its Ni(Ⅱ) complex have been synthesized. The crystal structure of the complex has been determined by X-ray diffraction method. The Ni(Ⅱ) is five-coordinated by three nitrogen atoms from the ligand and two Cl^- anions in a distorted trigonal bipyramidal environment: the N(2), Cl(1) and Cl(2) in equatorial plane; the N(1) and N(3) in axial positions. The UV-spectra and IR-spectra of the ligand and its Ni(Ⅱ) complex were recorded and discussed. The thermodynamic properties of the ligand with various bivalent metals were studied by potentiometric titrations and the order of the stability constants is in agreement with the Irving-Williams order in coordination chemistry. CCDC: 221750.     

(1S,2S)-1,2-二苯基乙二胺修饰Ir/HAP催化苯乙酮及其衍生物的不对称加氢反应

采用浸渍法在温和条件下制备了羟基磷灰石负载的铱催化剂(Ir/HAP), 并以X射线衍射(XRD), 透射电子显微镜(TEM), X射线光电子能谱(XPS), 比表面积测定(BET)以及附带能量散射X射线谱的扫描电子显微镜(SEM-EDS)等手段对载体和催化剂进行了表征. 以(1S,2S)-1,2-二苯基乙二胺((1S,2S)-DPEN)为手性修饰剂时, 该催化剂对苯乙酮及其衍生物不对称加氢反应表现出较高活性和对映选择性(ee). 在氢气压力为3.0 MPa、303 K条件下反应3 h, 苯乙酮及其衍生物的加氢转化率在94.7%以上, 其中生成2'-(三氟甲基)苯乙醇的对映选择性高达81.5%. 在不使用其它配体作稳定剂的情况下, 该结果比目前文献报道值高. 通过对比研究发现, 羟基磷灰石作为载体优于二氧化硅等其它无机载体. 催化剂通过简单离心分离可循环使用多次, 无明显的金属铱流失.     

N-乙基-1,10-菲罗啉-2-甲胺镍(Ⅱ)配合物的合成、晶体结构及性质研究

0IntroductionPhenanthrolinederivativescontainingaminegroupshavebothsoftandhardsitesandaregooddonorsformetalions.1,10鄄phenanthrolineanditsderivativeshavebeenextensivelyusedasligandsinbothanalyticalandpreparativecoordinationchemis鄄try[1].Mostoftheseworksh…     

载体对负载型Ni-B催化剂催化2-乙基蒽醌加氢制H2O2反应性能的影响

采用还原剂浸渍法将Ni-B非晶态合金负载到SiO2,γ-Al2O3和活性炭(AC)上,以2-乙基蒽醌选择加氧制H2O2为探针反应,系统研究了载体对Ni-B非晶态合金催化剂结构、热稳定性和催化性能的影响.结果表明,将Ni-B负载到载体上后,其晶化温度显著提高,各催化剂热稳定性依次为Ni-B/AC＞Ni-B/SiO2＞Ni...     

L-脯氨酸催化下甲基酮和1-芳基-2,2,2-三氟乙酮的不对称Aldol反应

Direct asymmetric aldol addition of methyl ketones to 2,2,2-trifluoro-1-phenylethanone and its ring-substituted derivatives was achieved using L-proline as a chiral promoter. Various optically active β-trifluoromethyl-β-hydroxy ketones were obtained in almost quantitative yields with moderate enantioselectivities up to 64 % ee.     

碱性条件下顺(2-乙酰胺基-1-溴-2-(对-甲氧基苯基)乙基)膦酸二乙酯的1,2消除反应

碱性条件下顺(2-乙酰胺基-1-溴-2-(对-甲氧基苯基)乙基)膦酸二乙酯的1;2消除反应;消除反应; 胺基溴化反应; 膦酸酯; 二维核磁共振谱     

Catalytic transformations of 1-octanol and 2-ethyl-1-hexanol over oxide catalysts, 1. Transition metal oxides as catalysts

A comparative study of 1-octanol and 2-ethyl-1-hexanol transformations over silica supported NiO, MnO₂, Cr₂O₃, Fe₂O₃, and ZnO has been performed. Zinca containing catalyst was found to be the most active in dehydrogenation and dehydration of the alcohols studied. ZnO dehydrogenating activity increased with supported oxide load.     

Catalytic transformations of 1-octanol and 2-ethyl-1-hexanol over oxide catalysts, part II. Promoted zinc oxide as a catalyst

Silica supported ZnO was modified with alkaline promoters to reduce its dehydrating activity towards 1-octanol and 2-ethyl-1-hexanol. Neutralization of zinca acidic centers led to the significant decrease of the yields of alkenes formed during dehydration. Simultaneously, the enhancement of ZnO dehydrogenating activity was observed. The effect of modifier diminished in the sequence: K₂CO₃>KOH>Na₂CO₃.     

Phase equilibria in ternary aqueous mixtures of 1,3-butanediol with 2-ethyl-1-hexanol at T = (298.2, 303.2 and 308.2) K

Experimental tie-line data for ternary system of (water + 1,3-butanediol (1,3-BD) + 2-ethyl-1-hexanol (2EH)) were determined at T = (298.2, 303.2 and 308.2) K under atmospheric conditions. This ternary system exhibits type-1 behavior of LLE. The experimental ternary LLE data were correlated using the NRTL model, and the binary interaction parameters were obtained. The average root-mean-square deviation between the observed and calculated mole fractions was 1.38%. Distribution coefficient and separation factor were measured to evaluate the extracting capability of the solvent. The separation factor values for the solvent used in this work were then compared with literature values obtained in our previous works for other butanediols.     

CuMgAlO_x复合氧化物催化甲醇乙醇Guerbet反应:M~(2+)/Al~(3+)比的影响

以类水滑石为前驱体,通过调控M~(2+)/Al~(3+)比制备了系列具有不同表面性质的MgAlO_x(MA)和CuMgAlO_x(CMA)催化剂,并分别应用于甲醛乙醛缩合反应(甲醇乙醇Guerbet反应的第二步反应)和甲醇乙醇Guerbet反应。采用NH_3/CO_2-TPD、XPS、H_2-TPR和H_2-TPD技术对催化剂表面酸碱性以及铜物种的性质进行了表征。结果表明,甲醇乙醇Guerbet反应性能与催化剂表面Cu~0比表面积和中强碱数目有关,提高Cu~0比表面积有利于甲醇乙醇脱氢生成甲醛和乙醛,增强中强碱数目能促进甲醛乙醛缩合反应。     

Viscosity of the systems m-xylene, +1-propanol, +2-propanol, +1-butanol, +t-butanol

Viscosities, η, of the systems, m-xylene, +1-propanol, +2-propanol, +1-butanol and +t-butanol have been measured for the whole range of composition at 303.15, 308.15, 313.15, 318.15 and 323.15?K. The variation of viscosities has been plotted against mole fraction of alkanols. Viscosities have been found to increase slowly up to a considerable concentration of alkanols, followed by a rapid rise of viscosities at higher concentrations. The slow rise of viscosity is attributed to dissociation of alkanols in m-xylene, while the rapid rise of viscosity is ascribed to self-association of alkanols. Excess viscosities, η^E, have been plotted as a function of mole fraction of alkanols. The curves show negative values for the whole range of composition, with minima occurring in alkanol-rich region.?η?and η^E have been fitted to appropriate polynomial equations. The study shows the effect of branching and chain length of alkanols on?η?and η^E.     

Anodic oxidation of sodium 2-mercaptobenztiazolate anion in the presence of 5-methyl-2-hexanol

The anodic oxidation of the sodium 2-mercaptobenztiazolate anion in alkaline solution yields a finely dispersed difficultly filterable form of di-(2-benztiazolyl)disulfide, an accelerant of the rubber sulfur vulcanization. A crucial problem in the establishing of the continuous di-(2-benztiazolyl)disulfide electrosynthesis is the choice of reaction mixture, which ensures easy filtration of the target product. It was found by using oscillographic voltammetry at platinum microelectrode that the sodium 2-mercaptobenztiazolate anion in aqueous alkaline solution in the presence of 5-methyl-2-hexanol is oxidized to a radical that undergoes dimerization, thus yielding easily filterable form of di-(2-benztiazolyl)disulfide. The obtained result is explained by assuming that the dimer formation occurs in the 5-methyl-2-hexanol adsorption layer at the electrode surface. A reaction scheme of the process is suggested.     

Esterification of phthalic anhydride with 1-butanol and 2-ethylhexanol catalyzed by heteropolyacids

Esterification of phthalic anhydride with 2-ethylhexanol and 1-butanol and ester decomposition of dioctyl phthalate (DOP) in presence of Keggin; H₃PW₁₂O₄₀, H₄SiW₁₂O₄₀, H₄SiMo₁₂O₄₀, Wells–Dawson; H₆P₂W₁₈O₆₂, H₆P₂W₁₇MoO₆₂ and Preyssler; H₁₄[NaP₅W₂₉MoO₁₁₀], H₁₄[NaP₅W₃₀O₁₁₀], type heteropolyacids have been investigated. The heteropolyacids with Preyssler and Wells–Dawson structures and their molybdenum substituted derivatives show higher activity in esterification and ester decomposition reactions than Keggin type heteropolyacids. A complete conversion of phthalic anhydride to dioctyl phthalate and dibutyl phthalate are achieved in 2 h in presence of molybdenum substituted Preyssler heteropolyacid. In the decomposition of dioctyl phthalate in the presence of Preyssler heteropolyacid, 2-ethylhexene is formed in quantitative yield.     

Solubility of carbon dioxide in 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate

Experimental results for the solubility of carbon dioxide in the ionic liquid 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate are not reported in the literature. To this end, we present in this work new solubility data for carbon dioxide in 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate for temperatures ranging from (303.2 to 343.2) K and pressures up to 6.7 MPa using a thermogravimetric microbalance. The carbon dioxide solubility was determined from absorption saturation (equilibrium) data at each fixed temperature and pressure. The buoyancy effect was accounted in the evaluation of the carbon dioxide solubility. Highly accurate equations of states for carbon dioxide and for ionic liquids were employed to determine the effect of buoyancy on carbon dioxide solubility. The solubility measurements are presented as a function of temperature and pressure. The present experimental solubility results have been successfully correlated using an extended Henry’s law equation.     

Dielectric relaxation studies of 1-hexanol and 1,2-hexanediol in heptane

Solutions of 1-hexanol and 1,2-hexanediol in heptane have been investigated tigated by means of dielectric time domain spectroscopy (TDS). The permittivity spectrum of 1-hexanol in heptane is characterized by a model function containing a sum of three elementary Debye dispersions, while 1,2-hexanediol in heptane is best described by a Cole-Davidson model function. It is shown that dilute solutions of 1-hexanol in heptane have a completely different behavior to that of 1,2-hexanediol. For the diol, the relaxation time levels off at a high value indicating an existence of higher hydrogen bonded complexes. It is possible to quantify the relative amount of monomeric 1-alcohol molecules from the dielectric spectrum. The monomerization rate for 1-hexanol upon dilution with heptane is initially low, but increases rapidly for mole fractions of heptane exceeding 0.4.     

Effect of 1-hexanol on the phase behavior of SDS/CTAB/NaBr/H2O system

Abstract

The influence of 1-hexanol on the phase behavior of sodium dodecyl sulfate (SDS)/cetyltrimethyl ammonium bromide (CTAB)/NaBr/H₂O system has been systematically investigated in this paper. The results showed 1-hexanol effectively dissolved the precipitate formed by the CTAB and SDS surfactants, while liquid crystal (LC) and aqueous two phase system (ATPS) were formed in a wider range. When the molar ratio of 1-hexanol to surfactant is higher than 1, the precipitation in the system disappeared completely and was transformed into ATPS and LC, indicating that alcohol inserted at least evenly between every two surfactant molecules and hence effectively weakened the electrostatic interaction between the anionic and cationic surfactants and limited the formation of precipitation. Polarizing microscope (POM) with crossed polarizers was employed to investigate the textures of liquid crystals. It was shown that the existence of lamellar LC was confirmed by “Maltese crosses” textures. Additionally, we showed that the thermal stability of LC was promising. The ATPS and LC regions remained stable and changed slightly when the temperature was increased from 40 to 70?°C. The results indicated that ATPS and LC of the system were quiet resistant to temperature with the addition of 1-hexanol.