Calorimetric analysis of the ethanolysis of 1,2-epoxybutane

Polyethers, which are produced by alcoholysis of oxiranes, are often used as solvents in chemical plants. The spectra of the products can be influenced by the choice of the catalyst (acid or base). The results of the base-catalyzed ethanolysis of 1,2-epoxybutane are displayed. The reaction was investigated calorimetrically by varying the molar ratio between ethanol and 1,2-epoxybutane, the starting temperature and the concentration of the catalyst sodium hydroxide. Additionally, the influence of the used alcohol will be shown in one example. To determine the activation parameters, the experiments were evaluated by the nonlinear software package TA-kin v3.3.     

Comparative reactivity of glycols in PET glycolysis

The kinetics of poly(ethylene terephthalate) (PET) glycolysis by diethylene glycol (DEG), dipropylene glycol (DPG), glycerol (Gly) and mixtures of these glycols have been studied with two experimental procedures: uncatalysed at 220 °C and catalysed at 190 °C. An experimental device was set up allowing the isothermal kinetics to be monitored. A precise initial reaction time was obtained by separately warming the glycol and the polyester at the temperature of reaction before mixing them.The reactivity order of different glycols varies according to the conditions of temperature and catalysis. Schematically, the global reactivity does depend not only on the chemical reactivity of the glycol but also on its physico-chemical properties: ability to solvate the solid polyesters and polarity of the reaction mixture. Attempts to find synergic effects failed for almost all mixtures, except the mixture DPG + Gly in which the PET is digested more quickly than in pure DPG or Gly.     

The Synthesis and Characterization of Cycloalkoxy-Linear Phosphazenes

The reactions of N -dichlorophosphoryl- P -trichlorophosphazene, Cl 3 P=N--P(O)Cl 2 with the sodium salts of cyclopentanol, cyclohexanol, 4-methylcyclohexanol, 3-methylcyclohexanol, 3-methylcyclopentanol are discussed. Pentacycloalkoxy-substituted phosphazenes were obtained from cyclopentanol, 4-methylcyclohexanol, 3-methylcyclohexanol, 3-methylcyclopentanol. Tetrasubstituted derivative also was obtained from cyclohexanol at the same conditions. The structure of products was defined by IR, 1 H, 13 C, 31 P NMR, and mass spectroscopy.     

Ring opening of epoxides with alcohols using Fe(Cp)2BF4 as catalyst

Fe(Cp)₂BF₄ is an efficient catalyst for the alcoholysis of aromatic, aliphatic, and cyclic epoxides giving excellent yields of the corresponding β-alkoxy alcohols under ambient conditions. The methanolysis of styrene oxide using Fe(Cp)₂BF₄ as a catalyst (5 mol %) gave excellent yield of 2-methoxy-2-phenylethanol with complete regio-selectivity. The ring opening of cyclic epoxides gave 77–97% yields of trans-β-methoxy alcohols, in 0.5–6 h. The use of 1,2-epoxyhexane and 1,2-epoxydodecane as substrates gave both regioisomers in excellent yields. The first order rate of reaction with respect to catalyst was observed for the kinetics of ring opening of 1,2-epoxyhexane with methanol.     

二氧化碳间接转化制化学品的研究进展

二氧化碳直接利用较为困难, 因此先将其转化为环碳酸酯等二氧化碳衍生物, 进而间接转化为其它化学品是实现二氧化碳资源化利用的重要手段之一, 具有良好的应用前景. 本文综合评述了二氧化碳转化为环碳酸酯继而间接利用的近期研究进展, 重点介绍了环碳酸酯的加氢反应、 醇解反应和氨解反应中的均相和多相催化体系, 对反应机理进行了阐述, 并展望了该领域仍待解决的问题和发展前景.     

An Fe3O4 nanoparticle-supported Mn (II)-azo Schiff complex acts as a heterogeneous catalyst in alcoholysis of epoxides

In this paper, an azo-containing Schiff base complex of manganese [Mn²⁺-azo ligand@APTES-SiO₂@Fe₃O₄] immobilized on chemically modified Fe₃O₄ nanoparticles has been used as a magnetically retrievable catalyst for the alcoholysis of different epoxides to their corresponding alkoxy alcohols with methanol, ethanol and n-propanol. The newly magnetic nanoparticles (MNPs) were characterized by Fourier transform infrared spectroscopy (FT-IR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and vibrating sample magnetometry (VSM).     

尿素羰基化作用研究进展

综述了尿素作为羰基化试剂合成氨基酸酯或碳酸酯类化合物及脲类化合物的研究进展,详细讨论了合成反应中所涉及的催化剂、反应机理和工艺条件,指出通过尿素醇解或胺解反应合成相应化合物是一条绿色工艺路线,具有广阔应用前景.     

A mild and efficient rhenium-catalyzed transfer hydrogenation of terminal olefins using alcoholysis of amine-borane adducts as a reducing system

[ReBr₂(NO)(CH₃CN)(PTA)₂] (PTA = 1, 3, 5-triaza-7-phosphaadamantane) catalyzes the alcoholysis of ammonia-borane and amine-boranes and the catalytic transfer hydrogenations of various terminal olefins. Excellent yields were achieved at 70 °C in isopropanol using tBuOK as a co-catalyst affording TOF values up to 396 h⁻¹.     

The alcoholysis of acetonitrile prompted by Br(o)nsted acidic ionic liquid [HSO3-pmim]HSO4

Br(o)nsted acidic ionic liquids based on imidazolium cation were employed as a series of environmentally benign catalysts and mediums in the alcoholysis of acetonitrile to synthesize ester. The results showed that Br(o)nsted acidic ionic liquid [HSO3-pmim]HSO4 was an efficient catalyst and medium for the alcoholysis of acetonitrile which could be recycled easily without obvious decline in catalytic activity, the highest yield could reach 85%.