酸催化二甘醇脱水环化反应研究

以硫酸、磷钨酸、ZRP-5分子筛为催化剂,研究了二甘醇(DEG)脱水环化的反应规律。结果表明,DEG发生分子内脱水环化反应,生成1,4-二氧六环(DOX),DEG分子间脱水不仅可以生成四甘醇、六甘醇等,同时可生成三甘醇、五甘醇等一系列的多甘醇(PEG)。不仅DEG可以脱水环化生成DOX,在反应中生成的PEG也同样可以进行生成DOX的反应。对于二甘醇(DEG)脱水环化反应,硫酸是性能优良的催化剂,反应可以在较低的温度下进行,馏出产物中DOX选择性大于95％。     

Fatigue Behavior of a Pavement Foundation with Recycled Aggregate and Waste HDPE Strips

A laboratory investigation was conducted to evaluate the fatigue behavior of an alternative pavement foundation material containing cement stabilized reclaimed crushed aggregate. Class C fly ash, and waste-plastic strip [high density polyethylene (HDPE)] reinforcement. The primary motivation for this research was to evaluate a composite that contained more than 90% recycled materials for use as an alternative foundation layer underneath conventional flexible or rigid pavement. The specific objectives of this study were (1) to evaluate the flexural fatigue behavior of the new composite, and (2) to evaluate the accumulation of fatigue damage in the material. The results indicate that the fatigue resistance of this material is similar to other traditional stabilized pavement materials. It was found that the dynamic elastic modulus remained approximately constant (degraded slowly) for most specimens up to the end of fatigue life. Fatigue damage computed using a dissipated energy approach showed that the damage accumulation in this material approximately follows Miner's rule for cumulative damage, which is often used in pavement engineering.     

Associative properties of perfluorooctyl end‐functionalized polystyrene–poly(ethylene oxide) diblock copolymers

The synthesis of 2,2,3,3‐tetrahydro‐perfluoroundecanoyl end‐functionalized polystyrene–poly(ethylene oxide) block (PS‐block‐PEO‐R_F) copolymers and their matching PS‐block‐PEO diblock copolymers was carried out by sequential anionic polymerization. Viscometry and ¹⁹F NMR studies show that the PS‐block‐PEO copolymers, in contrast to their matching PS‐block‐PEO‐R_F copolymers, exhibit a micellar rather than the associative behavior seen for the latter. However, the presence of an excess of fluorinated acid, used for end‐functionalization, produces a reduction of the associative behavior above the overlap concentration, with the fluorinated acid acting like a surfactant. A competition may also occur between PS—and R_F—mediated micellization. Copyright © 2004 Society of Chemical Industry     

以杂多酸为催化剂合成乙二醇-乙醚的研究

研究了杂多酸催化无水乙醇和环氧乙烷(EO)制备乙醇乙醚的醚化反应,考察了不同种类的杂多酸以及醚化反应工艺条件对反应活性和选择性的影响.结果表明,PW_(12)催化剂的反应活性高、反应温度低、选择性好,当用PW_(12)作催化剂,乙醇与环氧化乙烷之比为3.0(mol),反应温度45℃,反应时间1h时,转化率和选择性均超过97%.     

烃类在三甘醇和四甘醇中无限稀释活度系数的测定与关联

用气相色谱法分别测定了苯、甲苯、乙苯、正庚烷、正辛烷、正壬烷和正癸烷在三甘醇和四甘醇中的无限稀释活度系数 ,测定温度范围为 5 0～ 13 0℃。用修正的UNIFAC模型 (Dortmund)对上述不同温度下的无限稀释活度系数实验数据进行关联 ,得到了三甘醇和四甘醇与其它基团的相互作用参数 ,并将计算结果与实测值进行了比较。     

草酸二乙酯气相催化加氢合成乙二醇的研究

对草酸二乙酯气相催化加氢生成乙二醇反应进行了实验研究。研制了不含铬的铜基催化剂,并考察了催化剂的制备条件对反应结果的影响。结果表明,Cu/SiO_2质量比为0.67,活化温度为350℃时最佳。在上述催化剂制备的基础上,提出了最佳反应条件。     

Effect of antioxidant contained in poly(ethylene glycol) on cell fusion

The effect of antioxidants contained in poly(ethylene glycol) (PEG) on cell fusion was studied using L929 cells in the monolayer state. Hydroquinone monomethyl ether (HQME), 2-mercaptobenzimidazole (MB), butyl hydroxyanisole (BHA) and 2,6-di-(t-butyl)-4-methylphenol (BHT) were chosen from the antioxidants that have currently been used to protect commercially available PEG from oxidation. Cell culture was conducted in 40% w/w aqueous solution of PEG with a molecular weight of 3000 in the presence of different concentrations of antioxidants. BHA clearly enhanced membrane fusion of L929 cells with increasing concentration in PEG solution, whereas HQME, MB and BHT had no significant effect on cell fusion. The enhancement of cell fusion by BHA might be ascribed to balanced hydrophobicity and high water solubility in comparison with the other three antioxidants.     

Preparation of core–shell type nanoparticles of diblock copolymers of poly(L‐lactide)/poly(ethylene glycol) and their characterization in vitro

Core–shell type nanoparticles of poly(L ‐lactide)/poly(ethylene glycol) (LE) diblock copolymer were prepared by a dialysis technique. Their size was confirmed as 40–70 nm using photon correlation spectroscopy. The ¹H‐NMR analysis confirmed the formation of core–shell type nanoparticles and drug loading. The particle size, drug loading, and drug release rate of the LE nanoparticles were slightly changed by the initial solvents that were used. The drug release behavior of LE core–shell type nanoparticles showed an initial burst during the first 12 h and then a sustained release until 100 h. The degradation behavior of LE block copolymer nanoparticles was divided into three phases: the initial rapid degradation phase, the stationary phase, and the rapid degradation phase until complete degradation. It was suggested that lidocaine release kinetics were predominantly governed by the diffusion mechanism in the initial burst phase and after that by both of the diffusion and degradation mechanisms. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2625–2634, 2002     

Light scattering studies on crystallization in polyethylene terephthalate

The light scattering from the spherulites of polyethylene terephthalate grown near the glass transition temperature has been investigated. The Hv scattering profiles can be reproduced by the sum of the ideal spherulite scattering with the distribution of spherulite radius and the isotropic scattering from randomly oriented crystallites. The ratio of optical anisotropies in the isotropic scattering to the ideal spherulite scattering is obtained by the method established to eliminate the effects of the number density of spherulites and the coefficient depending on the experimental conditions. It is found that the anisotropy ratio is almost independent of the crystallization time and of temperature above 106 °C, while it is larger at a crystallization temperature of 103 °C. The spherulitic structure is discussed in terms of the anisotropy ratio.     

乙二醇合成工艺的研究进展

对国内外乙二醇合成的传统工艺:直接水合法、催化水合法和碳酸乙烯酯法进行了介绍;对乙二醇合成的新工艺,包括乙二醇和碳酸二甲酯联产法和C1化学法的工艺流程和发展前景进行了综述,其中,C1化学法主要分为乙烯合成法、合成气合成法和甲醛、甲醇合成法。作为合成气合成法之一的合成气偶联合成法,具有工艺要求不高、反应条件温和等优点,是目前最有希望大规模工业化生产乙二醇的工艺路线。