Blends of chlorinated isotactic polypropylene with poly(ethylene-co-vinyl acetate) II. Phase studies of the miscible blends

By measuring T_g, T_m and T_c (cloud point) phase diagrams for the four miscible blends of chlorinated isotactic polypropylenes (chlorine content 39.2 (CPP-40) and 49.8 wt.-% (CP-50)) with Poly(ethylene-co-vinyl acetate)s (vinyl acetate contents 40 (EVA-40) and 45 wt.-% (EVA-45)) were investigated. The blend of CPP-50 with EVA-40 was the most compatible of the four blend pairs.     

Influence of current density on oxygen transfer in an electroflotation cell

The objective of this work is to study the transfer of oxygen from gas to liquid phase in an electroflotation cell. The measurements were performed in a laboratory scale cell using insoluble electrodes, titanium coated with ruthenium oxide as anode and stainless steel as cathode. The volumetric mass transfer coefficient K _L a, was characterized for clean tap water as liquid phase for different values of current density (J). The global coefficient of mass transfer based on the liquid film, K _L , and the specific interfacial area, a, were characterized. A model which relates K _L a to current density was established. Different evaluation criteria of oxygen transfer in electroflotation process were determined and compared with other aeration process.     

一种高度炼化一体化的乙烯发展方案

简要介绍了三种炼化一体化新技术,由此提出了一种高度炼化一体化的乙烯发展方案,与常规的炼化一体化方案进行了对比分析,表明该方案的乙烯原料更加优质且轻质化,其丙烯/乙烯比可达1.1以上。     

脂肪醇聚氧乙烯(3)醚低温浑浊原因的探讨

通过在AEO3中添加不同加成数的AEO进行低温浑浊试验，并分析比较AEO3低温分层后的上清液与下层浑浊物中AEO的分布，发现EO加成数在5以上的AEO是导致AEO3低温浑浊的原因之一。在AEO3及其上清液中分别添加不同质量分数的脂肪醇、水以及醋酸钠进行低温浑浊试验，发现脂肪醇、水分和醋酸钠不是造成AEO3低温浑浊的原因，但会使AEO3在低温下容易冻结。     

Continuous production of structured phospholipids in a packed bed reactor with lipase from <Emphasis Type="Italic">Thermomyces lanuginosa</Emphasis>

The possibilities of producing structured phospholipids between soybean phospholipids and caprylic acid by lipase-catalyzed acidolysis were examined in continuous packedbed enzyme reactors. Acidolysis reactions were performed in both a solvent system and a solvent-free system with the commercially immobilized lipase from Thermomyces lanuginosa (Lipozyme TL IM) as catalyst. In the packed bed reactors, different parameters for the lipase-catalyzed acidolysis were elucidated, such as solvent ratio (solvent system), temperature, substrate ratio, residence time, water content, and operation stability. The water content was observed to be very crucial for the acidolysis reaction in packed bed reactors. If no water was added to the substrate during reactions under the solvent-free system, very low incorporation corporation of caprylic acid was observed. In both solvent and solvent-free systems, acyl incorporation was favored by a high substrate ratio between acyl donor and phospholipids, a longer residence time, and a higher reaction temperature. Under certain conditions, the incorporation of around 30% caprylic acid can be obtained in continuous operation with hexane as the solvent. Presented at the 95th American Oil Chemists' Society Annual Meeting and Expo in Cincinnati, Ohio, May 10, 2004.     

NUMERICAL SIMULATION OF THE GAS-PARTICLE FLOW IN RISERS I: THE MACRO FLOW BEHAVIOR

The steady gas-particle flow in risers under variant operating conditions was predicted based on a k-ε-k_p-ε_p-Θ two-fluid model, which describes the dense turbulent gas-particle flow by the Eulerian method, considering the turbulence of both gas and particles as well as the particles' collisional effects. Much information on the macro flow behavior in risers, such as the profiles of local particle axial velocity, solids volume fraction, and solids mass flux in different operating regimes was obtained, and the predicted results show satisfactory agreement with experimental data. Further analysis of the predictions gives the comprehension of flow characteristics on the macro scale.     

Frying Performance of No-<Emphasis Type="Italic">trans</Emphasis>, Low-Linolenic Acid Soybean Oils

Two extruded-expelled physically refined soybean oils with reduced contents of linolenic acid, ultra-low- linolenic acid (ULL, 1.5%) and low-linolenic acid (LL, 2.6%), and a extruded-expelled physically refined control oil (control, 5.3% linolenic acid) were evaluated by frying French fries in a commercial-like setting for 6 h day⁻¹ during 23 days. The oils became darker, increased in yellow color at the beginning, and became redder and less green throughout the process. Free fatty acids levels were not different among the oils until day 14, after which, ULL was different from the control for the remainder of frying. The conjugated dienoic acid values were greatest in the control. Generally, ULL and LL oils had lower percentages of polar compounds than did the control, providing a frying life 2 days longer than the control and ~30% increase in frying time. A trained sensory panel evaluated the French fries on days 2, 5, and 6. Buttery and potato flavors decreased, and rancid and painty flavors increased over frying time for all products. Rancid flavor was highest in the fries from the control oil. Overall, the ULL and LL oils performed better than did the control oil and ULL tended to perform better than the LL.     

聚乙二醇对脂肪醇聚氧乙烯醚低温浑浊影响的研究

通过一系列低温浑浊试验考察了聚乙二醇含量与分子质量对脂肪醇聚氧乙烯醚(AEO3)低温浑浊的影响，并分析AEO3低温分层后的上清液和下层浑浊物中聚乙二醇的含量与分布，发现分子质量在600以上的聚乙二醇是影响AEO3低温浑浊的重要原因。     

六铝酸钙材料的合成及其显微结构研究

分别采用轻质碳酸钙和活性氧化铝 ,或纯铝酸钙水泥和活性氧化铝为初始原料 ,反应烧结合成了六铝酸钙 (CA6)材料 ,研究了原料和成型压力对合成材料的烧结性能和显微结构的影响 ,同时借助于XRD、TG -DSC、SEM和EDAX等测试手段对其反应过程、物相变化和显微结构进行了分析和观察。研究结果表明 :(1) 130 0℃时 ,合成材料的主晶相为刚玉相和CA2 ,并开始有CA6形成 ;温度升至14 0 0℃ ,CA6大量生成 ;15 0 0℃时反应完成 ,产物全部为CA6相。 130 0～ 15 0 0℃时 ,上述反应表现为体积膨胀过程 ,试样的体积密度和径向线收缩率随温度的变化不大 ;而高于 15 0 0℃时 ,试样明显趋向烧结 ,体积密度升高 ,线收缩率加大。采用纯铝酸钙水泥和活性氧化铝合成的试样的体积密度均高于采用轻质CaCO3 和活性氧化铝的 ,尤其在烧成温度高于 15 0 0℃时。坯体的成型压力对这两种合成试样的烧结性能均没有显著影响。 (2 )合成六铝酸钙材料的晶粒形貌与合成工艺有关 ,制备片状晶粒的六铝酸钙材料需满足两个条件 :一是晶核有足够的发育空间 ,二是从晶核生长形成片状结构需足够的物质扩散。采用纯铝酸钙水泥和活性氧化铝为原料的试样 ,其CA6晶核很容易发育成片状晶形 ,且随着坯体成型压力的增加 ,片状CA6有向等轴状发展的趋势 ;采用     

Study of the polymerization of 1-octadecene with different rnetallocene catalysts

Summary 1-Octadecene (C18) was polymerized by using different metallocene catalysts. The rac-Et(Ind)₂ZrC1₂/MAO (I) and rac-Me₂Si(Ind)₂ZrC1₂/MAO (III) presented the highest activity as compared with ra-Et(2-Me-Ind)₂ZrCl₂/MAO (II) and Ph₂C(Flu)(Cp)ZrC1₂/MAO (IV) catalysts. Catalyst IV produced polymers with highest molecular weights. The microstructure of the polymers was determined by ¹³C-NMR spectroscopy. Catalyst systems I, II and III produced isotactic polymers while catalyst IV produced polymers with mainly syndiotactic structures but with large amount of stereoregular error. Received: 21 June 2002/Revised version: 4 November 2002/ Accepted: 4 November 2002