Vapor-phase synthesis of ethyltert-butyl ether on heteropoly acid-polymer composite film catalysts

H₃PMo₁₂O₄₀-polysulfone and H₃PMo₁₂O₄₀-polyphenylene oxide composite film catalysts were prepared by a membrane preparation technique. They showed the higher catalytic activities than H₃PMo₁₂O₄₀ in the vapor-phase synthesis of ethyl tert-butyl ether.     

丁二酸二(二乙二醇单甲醚)酯的制备及其应用

以二乙二醇单甲醚和丁二酸酐为原料,对甲苯磺酸为催化剂,在二甲苯中经开环反应合成了丁二酸二(二乙二醇单甲醚)酯(1),其结构经1H NMR和IR确证。采用恒电流充电法、循环伏安扫描和充放电性能测试了电解质溶液[1.2 mol·L-1双三氟甲基磺酰亚胺锂(LiTFSI)/V(1)∶V(EC)∶V(DEC)=3∶3∶4]在锂离子电池中的电化学性能。结果表明:1与石墨负极有较好的相容性,在0 V~2 V,0.1 C下充放电20次后放电比容量为346.2 mAh·g-1,容量保持率为111.10%。     

网络型聚醚酯弹性体聚柠檬酸二甘醇酯的合成与性能

用一缩二乙二醇(二甘醇)和柠檬酸通过熔融缩聚的方法,合成了一种新型的网络型聚醚酯弹性体—po-ly(diethylene glycol citrate)(PDGC).用FTIR初步表征了预聚物的结构;通过ATR-FTIR、DSC、XRD等表征了PDGC的结构;测试了材料的静态水接触角、力学性能以及体外降解性能,考察了单体的摩尔比以及后期交联时间对材料上述性能的影响.     

Quantitation of diethylene glycol monoethyl ether in citrus oils

The use of diethylene glycol monoethyl ether as a flavor solvent is restricted. Since existing methods of quantitation are tedious or require sophisticated multi-dimensional GC instrumentation, a simple method has been developed using low cost GC-MS. Monitoring of ions 31 and 45 enables quantitation of DEGEE in essential oils at levels down to 1 μg/g with accuracy equal to or better than 15%.     

Identification and quantification of polyethylene glycol types in polyethylene glycol methyl ether and polyethylene glycol vinyl ether

Quantitative determination of polyethylene glycol (PEG) impurities in two monofunctional polyglycol types, PEG methyl ether (M-PEG) and PEG vinyl ether (V-PEG), has been carried out by reversed-phase liquid chromatography with evaporative light scattering detection (ELSD). In addition to optimizing the resolution between PEG and monofunctional PEG peaks, the major focus has been to determine the molecular weights of PEG impurities in M-PEG and V-PEG of diverse molecular weights. The latter is achieved by examining liquid chromatography–mass spectrometry (LC–MS) mass spectra of both monofunctional PEG and PEG in several cases, and matching peak retention times with those of available PEG standards for all M-PEG and V-PEG sample types. This information is helpful in selecting the appropriate PEG standard to determine PEG content in each sample type. ELSD response factors for various PEG standards have also been compared. It has been found that PEG standards with molecular weights from 1000 Da to 8000 Da show responses that are within 10% of each other. However, a low molecular weight PEG such as PEG 400, provides approximately 30% less response compared to its higher molecular weight counterparts.     

Viscosity of binary mixtures of 2-ethoxyethanol with ethylene glycol,diethylene glycol,triethylene glycol and tetraethylene glycol systems at T = (293.15, 298.15 and 303.15) K

Viscosities, at T = 293.15, 298.15 and 303.15 K, in the binary mixtures of 2-ethoxyethanol with ethylene glycol, diethylene glycol, triethylene glycol and tetraethylene glycol have been measured as a function of composition. From the experimental data the deviations in the viscosity have been calculated. The viscosity data, at T = 298.15 K, were correlated with equations of Hind et al., Grunberg and Nissan, and Frenkel. The results are discussed in terms of intermolecular interactions and structural properties of studied binary mixtures.     

Microemulsion polymerization of styrene stabilized by sodium dodecyl sulfate and diethylene glycol monoalkyl ether

The effects of the cosurfactants diethylene glycol monoalkyl ether [C _i H_{2 i +1}O(CH₂CH₂O) _j OH (C _i E _j ; i=4, 6 and j=1, 2)] on the formation of an oil-in-water styrene (ST) microemulsion and the subsequent free radical polymerization were studied. For comparison, the data for the C _i H_{2 i +1}OH (C _i OH; i=4, 6) systems obtained from the literature were also included in this work. Sodium dodecyl sulfate was used as the surfactant. The pseudo three-component phase diagram (macroemulsion, microemulsion and lamellar gel phases) was constructed for each cosurfactant. The primary parameters selected for the polymerization study are the concentrations of cosurfactant and styrene. The number of latex particles nucleated is much smaller than that of the microemulsion droplets initially present in the reaction system. Limited flocculation of the latex particles occurs to some extent during polymerization. Among the cosurfactants investigated, the C₄OH-containing polymerization system is the least stable. By contrast, the diethylene glycol monoalkyl ether group of C _i E _j tends to enhance the latex stability. C _i E _j is more effective in stabilizing the ST microemulsion and the subsequent polymerization in comparison with the C _i OH counterpart. Received: 24 December 1999 Accepted: 9 February 2000     

Terpolymerization of methyl methacrylate, poly(ethylene glycol) methyl ether methacrylate or poly(ethylene glycol) ethyl ether methacrylate with methacrylic acid and sodium styrene sulfonate: determination of the reactivity ratios

Materials bearing ionic monomers were obtained through free radical terpolymerization of methyl methacrylate (MMA), poly(ethylene glycol) methyl ether methacrylate (PMEM) or poly(ethylene glycol) ethyl ether methacrylate (PEEM) with methacrylic acid (MA) and sodium styrene sulfonate (NaSS). The reactions were carried out in dimethyl sulfoxide using azobis(isobutyronitrile) as initiator. The reactivity ratios of the different couple of monomers were calculated according to the general copolymerization equation using the Finnemann-Ross, Kelen-Tüdos and Tidwell-Mortimer methods. The values of the reactivity ratios indicate that the different monomer units can be considered as randomly distributed along the chains for terpolymerizations of MMA, PMEM or PEEM with MA and NaSS. The average composition of the comonomers in the different terpolymers were calculated, showing a good agreement between the experimental and theoretical compositions. The instantaneous compositions are constant until about 70% of conversion. For higher conversions, the insertion of ionic monomers increases or decreases according to the system studied.     

Synthesis of superparamagnetic and thermoresponsive hybrid nanoparticles via surface‐mediated RAFT polymerization of di(ethylene glycol) ethyl ether acrylate and (oligoethylene glycol) methyl ether acrylate

A reversible addition‐fragmentation chain transfer (RAFT) agent was directly anchored onto superparamagnetic Fe₃O₄ nanoparticles (SPNPs) in a simple procedure using a ligand exchange reaction of 2‐[(dodecylsulfanylcarbonylthiolsulfanyl) propionic acid] (DCPA) with oleic acid initially present on the surface of Fe₃O₄ nanoparticles. The DCPA‐modified SPNPs were then used for the surface‐mediated RAFT polymerization of di(ethylene glycol) ethyl ether acrylate and (oligoethylene glycol) methyl ether acrylate to fabricate structurally well‐defined hybrid SPNPs with temperature‐responsive poly[di(ethylene glycol) ethyl ether acrylate‐co‐(oligoethylene glycol) methyl ether acrylate] shell and magnetic Fe₃O₄ core. Evidence of a well‐controlled surface‐mediated RAFT polymerization was gained from a linear increase of number‐average molecular weight with overall monomer conversions and relatively narrow polydispersity indices of the copolymers grown from the SPNPs. The resultant hybrid nanoparticles exhibited superparamagnetic property with a saturation magnetization of 55.1–19.4 emu/g and showed a temperature‐responsive phenomenon as the temperature changed between 25 and 40 ^°C. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 3420–3428     

A new catalyst for direct synthesis of dimethyl ether from synthesis gas

A new catalyst has been prepared by coprecipitation sedimentation method developed in our laboratory. It exhibits excellent catalytic activity, selectivity and stability for conversion of synthesis gas to dimethyl ether: conversion of CO 92%, selectivity of dimethyl ether 98%. Catalytic properties of the catalyst show no evident change after being used for 100 h.     

Comparison of the performance of different hybrid catalysts for direct synthesis of dimethyl ether from synthesis gas

Nine hybrid catalysts have been prepared, characterized and tested in a micro reactor for the direct synthesis of dimethyl ether. The physical mixtures of H-MFI-90 with ICI or KMT catalysts showed better performance.     

Densities and relative permittivities of binary mixtures containing dipropylene glycol monomethyl ether

Relative permittivities () and densities () of numerous binary mixtures of dipropylene glycol monomethyl ether (1)+propylene glycol mono n-butyl ether (2) and dipropylene glycol monomethyl ether (1)+dipropylene glycol mono n-butyl ether (2) at five temperatures, between (293.15 and 313.15) K, are reported. The excess molar volumes (V ^E) and the relative permittivity deviations () were calculated from these experimental data. The results are discussed in terms of intermolecular interactions in the bulk of studied the binary mixtures.     

Design of novel catalyst imbedding heteropoly acids in polymer films: Catalytic activity for ethanol conversion

Membrane-like H₃PMo₁₂O₄₀ or H₅PMo₁₀V₂O₄₀-imbedded polymer films were prepared by blending these materials using a chloroform-methanol mixture as solvent, and they were tested as catalysts for the ethanol conversion reaction in a continuous flow fixed-bed reactor. It was found that the chloroform-methanol mixture itself gave no influence on the catalytic activity of bulk H₃PMo₁₂O₄₀ and H₅PMo₁₀V₂O₄₀. Polysulfone, polyethersulfone and polyphenylene oxide were used as blending polymers in this study. H₃PMo₁₂O₄₀-imbedded polymer films showed a higher catalytic activity than H₃PMo₁₂O₄₀ itself due to uniform and fine dispersion of H₃PMo₁₂O₄₀ through polymer films, but the extent of activity and selectivity was varied according to a kind of polymer materials. It was revealed that H₃PMo₁₂O₄₀ or H₅PMo₁₀V₂O₄₀-imbedded polyphenylene oxide film showed much higher oxidation catalytic activity than the corresponding bulk heteropoly acids. This may be due to the interaction (or bonding) of proton of heteropoly acid with polyphenylene oxide, judging from the fact that glass transition temperature of polyphenylene oxide was increased after blending with heteropoly acid. The catalytic activity of the heteropoly acid imbedded in the same polymer was greatly affected by the composite of heteropoly acid. The permeabilities of reactants through polymer films also affected the product selectivity.     

Ternary diffusion coefficients of diethylene glycol and lithium chloride in aqueous solutions containing diethylene glycol and lithium chloride

In this work, ternary diffusion coefficients of diethylene glycol and lithium chloride in aqueous solutions containing diethylene glycol and lithium chloride were reported for temperatures (303.2, 308.2, and 313.2 K) using the Taylor dispersion method. The investigated ternaries contained total glycol–salt concentrations of 10, 15, and 20 wt%. The main diffusion coefficients (D₁₁ and D₂₂) and the cross-diffusion coefficients (D₁₂ and D₂₁) were discussed as function of temperature and concentration. A modified equation originally proposed by Batchelor [1] for mixture of hard spheres in a continuum solvent was used to correlate the present diffusion coefficient data and the results are satisfactory.     

可磁性回收纳米级负载型杂多酸催化剂用于水中生物活性化合物的绿色合成(英文)

12‐Tungstophosphoric acid supported on aerosil silica and silica‐coated γ‐Fe2O3 nanoparticles was prepared and characterized using transmission electron microscopy,scanning electron microscopy,and inductively coupled plasma atomic emission spectroscopy.The catalytic activity of the two prepared catalysts was compared in the synthesis of 1,8‐dioxo‐9,10‐diaryldecahydroacridines in water.12‐Tungstophosphoric acid was highly dispersed on the silica‐coated γ‐Fe2O3 nanoparticles and showed higher activity and a higher reuse number compared with the acid supported on aerosil silica.The catalyst could be recovered simply by using an external magnetic field and could be reused several times without appreciable loss of its catalytic activity.     

Microwave-assisted NaHSO4-catalyzed synthesis of ricinoleic glycol ether esters

The synthesis of several ricinoleic acid glycol ether esters by high-pressure microwave radiation is described. Ricinoleic acid which is from castor oil reacted fastly with glycol ethers in the presence of NaHSO₄?·?H₂O and dichloromethane (DCM) in special microwave reactor. The influences of reaction factors such as catalyst and solvent type, reaction temperature, and time were investigated and the optimal reaction conditions were obtained. The activity of catalyst had a higher performance up to the 10th cycle and the excellent values of turnover numbers and turnover frequency were obtained. Compared with the traditional esterification in reflux heating systems., the microwave-assisted process has many advantages such as shorter reaction time, less side effects, higher yield, which is a great potential for the development of green chemistry.     

A Facile and Efficient synthesis for A Series of Bis(N-imidazolylethyl) Ethers

Multi-dentateligandssuchasopen-chainandcycliccrownethershavereceivedextensiveintCrestsandbeenmuchstudiedinhost-guestinteraction,supramolecularandbioorganicchemistry".Asabindingand/orcatalyticsiteintheactivecenterofmetalloenzymesandnon-metalloenzymes,imidazoleplaysaveryimportantroleinbiologicalsystem.Imidazole-basedbiomimeticmodelsandmacrocycles,especiallyrecentimidazoliumcyclophaneshavebeenpaidincreasingattention5-ll.Inspiteofthis,onlyoneliteratUre,toourknowledge,reportedthesynthesisofbis(N-i…     

Kinetics of liquid-phase synthesis of ethyl tert-butyl ether from tert-butyl alcohol and ethanol catalyzed by ion exchange resin and heteropoly acid

Synthesis of ethyl tert-butyl ether (ETBE) from ethanol (EtOH) and tert-butyl alcohol (TBA) in the liquid phase was studied by using ion exchange resin, Amberlyst 15 (A15) in the H⁺ form and heteropoly acid, H_0.5Cs_3.5SiW₁₂O₄₀(HPA). Experiments were carried out in a stirred batch reactor with different temperatures under atmospheric pressure. It was found that water will inhibit the reaction rates greatly and the dehydration of TBA could not be neglected in this study. A kinetics model which considered the inhibition of water and the decrease of volume was proposed. The experimental results agreed well with the model. © 1995 John Wiley & Sons, Inc.     

一步法合成二甲醚整体式催化剂的制备及反应性能研究

以蜂窝陶瓷为载体、γ-Al₂O₃为惰性涂层、C301/HZSM-5为活性组分制备出一种整体式合成二甲醚催化剂。BET、XRD和SEM分析结果表明,活性组分均匀负载在载体表面上,催化剂具有良好的结构和织构特点。在固定床反应器中考察了整体式催化剂上CO加氢一步法合成二甲醚的反应性能,并与C301/HZSM-5颗粒（粉末）催化剂进行了比较。在温度260℃、压力4.0MPa、合成气空速1500mL/(g·h)的条件下,整体式催化剂上CO转化率达到79.62%,二甲醚选择性为70.58%,分别比C301/HZSM-5颗粒催化剂高出7.78%和9.44%。100h的稳定性实验结果表明,整体式催化剂可以保持较高的活性和选择性,而颗粒状催化剂的活性有明显的下降。