酸处理Beta分子筛对十氢萘加氢开环反应影响

研究了酸处理过程对Beta分子筛Br nsted酸和Lewis酸分布及其作为载体催化十氢萘加氢开环反应的影响。采用XRD、BET、XRF、Py-FTIR等表征了不同浓度盐酸处理的分子筛,结果表明,酸处理后Beta分子筛结晶度及孔径无明显变化,比表面积先增加后降低。随盐酸浓度的增加,n（SiO₂）/n（Al₂O₃）增大,总酸量逐渐降低;在盐酸浓度大于0.1 mol/L时,酸处理主要改变了分子筛的B酸位。十氢萘加氢开环反应实验结果表明,B酸位对Beta分子筛催化十氢萘开环反应影响较大,酸性越强越易导致作为载体的Beta分子筛失活。0.1 mol/L盐酸处理得到的催化剂酸性适宜,比表面积最大,活性及开环异构产物的产率最高。     

Polymer interface changes in electrophoretic deposition

A Monte Carlo computer simulation model for the electrophoretic deposition of polymer chains on a discrete lattice is used to study the polymer density profile, interface growth, and its dependence on field, temperature, and molecular weight. The interface width (W) decreases WE^−1/2 on increasing the field (E). Width (W) depends non-monotonically on the temperature (T): a power-law decay is followed by a power-law increase on raising the temperature. Monotonic decay of the interface width with the molecular weight is possibly a stretched exponential. Conformation and dynamics of a tracer chain is used to probe its characteristics in interface to bulk region. The root mean square (rms) displacement of the center of mass of the tracer chain shows an ultra-slow motion, Rt^ν (ν0.1–0.01 at E=0.1–1.0) as the driven chain moves deeper from interface to bulk. Longitudinal compression of the radius of gyration (R_g) of the chain increases with the field; transverse components (R_gx, R_gy) are larger than the longitudinal component (R_gz). The transverse component (R_gx(y)) becomes oscillatory due to periodic squeezing at high fields as the field competes with the polymer barriers.     

Criteria and methodology for the evaluation of conservation interventions on treated porous stone susceptible to salt decay

Susceptibility of stone to salt decay is directly related to its microstructural and mechanical characteristics. In the present work, a porous stone from a quarry in Cyprus was examined. Samples of this stone were consolidated and protected with certain conservation materials. The modification of microstructural characteristics of the stone was evaluated by mercury intrusion porosimetry, while its mechanical characteristics were measured by compressive and bending strength tests. From these data, the susceptibility of Cyprus stone to salt (NaCl) decay was estimated. The values of crystallization pressure of NaCl were calculated and compared to the experimentally measured compressive and tensile strength of the stone, in order to examine the probability of stone disruption due to salt crystallization. The development of the phenomenon after coarse pores’ filling with crystals, i.e. crystallization of salts in capillaries or mechanical failure of the stone, was determined by thermodynamic analysis. Additionally, artificial weathering tests of marine salt spray were performed for the evaluation of stone’s durability after the conservation. The treated stone proved to be resistant to salt decay, as it presented ameliorated microstructural and mechanical characteristics, concerning decay due to soluble salt crystallization. The most possible thermodynamic scenario was small pores repletion with crystals, avoiding mechanical failure of the stone.     

Flow and Flow Decay of Refractory Castables

Installation of refractory castables depend not only on flow,but also on how soon the flow is lost because of setting.The loss of flow(flow decay)has always been one of the main problems of refractory castable manufacturers,a problem that has not been too well described in literature.The flow decay has been studied for a castable system based on alumina,pointing out some general trends.The flow decay was found very temperature sensitive,being strongly accelerated by temperature increases.To compensate for excessive flow loss,a retarder like citric acid may be used.Thus flow decay was measured as a function of citric acid(retarder) addition at 35℃.     

水平油气两相流中液滴分布的衰减系数

引　言在石油、天然气的开发过程中 ,在通常的操作条件下 ,水平管线中的两相分离流 (指分层流和环状流 )是常见的流动结构 在较高的气相流速时 ,液滴可从液膜表面上被撕破而进入到中心气核中去 .液滴和其携带流体间的相互作用和相间滑移的存在强烈地影响着流动时的压降特性 ,而液滴浓度在管截面上的不均匀分布 ,也影响气相速度的分布以及对相份额的准确计算和测量 .众所周知 ,管路的压降和相份额数据是两相或多相流输送管线和管路终端处理设备的设计及安全、经济运行的最重要依据 .由此可见 ,在两相输送过程中对液滴传输特性研究的重要性 .…     

Flame retardancy,antifungal efficacies,and physical–mechanical properties for wood/polymer composites containing zinc borate

This work aimed to examine flame retardancy, antifungal performance and physical–mechanical properties for silane‐treated wood–polymer composites (WPCs) containing zinc borate (ZnB). ZnB with content from 0.0 to 7.0 wt% was added to WPCs, and silane‐treated wood contents were varied. The polymers used were poly(vinyl chloride) (PVC) and high‐density polyethylene (HDPE). The decay test was performed according to the European standard EN 113. Loweporus sp., a white‐rot fungus, was used for antifungal performance evaluation. Antifungal performance was observed to decrease with wood content. Incorporation of ZnB at 1.0 wt% significantly increased the antifungal performance of WPCs. ZnB content of greater than 1.0 wt% lowered the antifungal properties of WPCs. The results suggested that the wood/PVC composite exhibited better antifungal performance than the wood/HDPE composite. The addition of wood flour to PVC and HDPE decreased flame retardancy, whereas the incorporation of ZnB retained the flame retardancy. ZnB was found to be more appropriate for wood/PVC than wood/HDPE as a result of hydrogen chloride generated from the dehydrochlorination reaction of PVC. The results indicated that the addition of ZnB did not affect the physical‐mechanical properties of neat polymers and the composites. Copyright © 2016 John Wiley & Sons, Ltd.     

The modelling and experimental study on molecular diffusion coefficient of CO2 in N-methyl pyrolidone

In this study, batchwise absorption of CO₂ in N-methyl pyrolidone (NMP) was experimentally performed at different conditions using pressure decay method, and as a result, the equilibrium data, Henry’s law constants, and kinetic data were reported. It was shown that solubility and diffusivity are two important factors affecting the kinetic behaviour of the system. This absorption system was mathematically modelled using Fick’s second law accompanied by a time-dependent boundary condition. Thus, the diffusion coefficients of CO₂ in NMP were calculated under different operating conditions by means of the experimental kinetic data. Furthermore, the influence of temperature and pressure on the diffusion coefficient of CO₂ in NMP was analysed.     

Siting and Distribution of Framework Aluminium Atoms in Silicon-Rich Zeolites and Impact on Catalysis

Siting of Al atoms in the framework T sites, in zeolite rings and channel/cavity system, and the distribution of Al atoms between single Al atoms and close Al atoms in various Al-O-(Si-O)_n-Al sequences in Si-rich zeolites represent key parameters controlling properties of counter ion species. Framework Al siting and distribution is not random or controlled by simple rules and depends on the conditions of the zeolite synthesis. Al in Al-O-(Si-O)₂-Al in one 6-MR and single Al atoms predominate in Si-rich zeolites and their population can be varied to a large extent. The siting and distribution of framework Al atoms dramatically affect catalytic activity/selectivity both of protonic and transition metal ion-containing zeolite catalysts.     

Beyond shape selective catalysis with zeolites: Hydrophobic void spaces in zeolites enable catalysis in liquid water

Zeolites confine active sites within void spaces of molecular dimension. The size and shape of these voids can be tuned by changing framework topology, which can influence catalytic reactivity and selectivity via coupled reaction‐transport phenomena that exploit differences in transport properties among reactants and/or products that differ in size and shape. The polarity and solvating properties of intrazeolite void environments can be tuned by changing chemical composition and structure, ranging from hydrophobic defect‐free pure‐silica surfaces to silica surfaces containing hydrophilic defect sites and/or heteroatoms. Here, we discuss how the polarity of zeolite voids influences catalytic reactivity and selectivity via the partitioning of reactant, product, and solvent molecules between intrazeolitic locations and external fluid phases. These findings provide a conceptual basis for developing selective catalytic processes in aqueous media using hydrophobic zeolites that are able to adsorb organic reactants while excluding liquid water from internal void spaces. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3349–3358, 2013     

萘酚偶氮颜料

该文介绍了β-萘酚颜料的发展历史、化学性质及制作过程,β-萘酚颜料的性能及应用;并介绍了目前市场上的商用,该颜料系列色谱有橙、红、蓝相红直到紫红,其中颜料橙P.0.5以及颜料红P.R.3因为有较好的性价比,仍然保有一定的市场份额。