超临界CO2中的高分子合成研究进展

介绍了超临界二氧化碳的特殊性质，综述了超临界二氧化碳为介质的高分子合成方面的应用进展情况．皿示出超临界二氧化碳是一种对环境无污染且价廉的绿色介质，具有广阔的应用前景。     

Platinum-Containing Diamond-like Carbon Thin Films

This paper reports a composite thin film of platinum–diamond-like carbon (Pt-DLC). "Nonreactive" and reactive rf sputter deposition techniques were used for the preparation of these thin films under various ratios of Ar/CH₄. As-deposited thin films were characterized for microstructures using transmission electron microscopy and Raman spectroscopy, compositions using electron probe for microanalysis, surface morphology using scanning electron microscopy, and sheet resistance using four-point probe. Correlations among the growth parameter, film composition, and structure are presented. Such correlations were found to depend on the deposition technique. Improved electrical conductivity and reduced film stress were also found due to the addition of platinum to DLC.     

超临界二氧化碳化学

本文简要介绍了在超临界条件下，二氧化碳化学的新进展，开发研究动向及其发展趋势。     

超临界二氧化碳萃取低挥发性液体混合物的相平衡

在半连续式实验设备中分别测定了苯甲醇－２－苯乙醇和苯甲酸酯－苯甲醇的等摩尔混合物与超临界ＣＯ２三元系相平衡数据。实验温度分别为３０８．２Ｋ和３１８．２Ｋ，压力范围为８～２０ＭＰａ。实验结果表明：对第一个三元系，两种液体在超临界ＣＯ２中的溶解度与ＣＯ２在液相中溶解行为密切相关；对第二个三元系，较高压力下，超临界流体相中苯甲酸甲酯浓度突然增大，而苯甲醇浓度变化不明显。通过引入考虑分子体积差别的二元作用参数，用Ｐｅｎｇ－Ｒｏｂｉｎｓｏｎ方程对气液平衡数据进行了关联。     

超临界CO2萃取技术提取生理活性物质的研究进展

超临界CO2萃取技术主要是利用超临界CO2在其临界点附近所具有的一些独特的性质对物质进行提取分离的方法，作为一种高新分离技术，该技术具有能保持产品生物活性，提高产品的提取率和纯度等优点，该法操作简单可行，介绍超临界CO2萃取技术的基本原理及特点，综述用该技术提取生理活性物质的研究现状，并展望了其在这一领域的应用前景。     

超临界二氧化碳在聚合物共混中的应用

概述了超临界二氧化碳(SC-CO2)在聚合物熔体中的溶解度,SC-CO2对熔体黏度和共混物两相间黏度比以及界面张力的影响,介绍了SC-CO2对聚合物共混物微观形态的影响。     

基片上镀TiO2薄膜光催化降解有机磷农药

以基片上镀ＴiO2薄膜为光催化剂降解有机磷农药. 结果表明,基片为铜丝比基片为钛网和硅片时光催化降解率高;随光照时间延长,光降解率增大;当溶液pH值为2时,光降解率最高;对于钛网,当退火温度为450℃时光催化降解率最大;用HNO3调节溶液pH值比用H2SO4和HCl调节光降解率高;膜使用次数越多,光催化活性越小;硫杆磷酸酯类农药比磷酸酯类农药更容易发生光催化降解;农药浓度越稀,越容易进行光催化降解. 当用铜丝作为基底物、光照时间为60 min 时,光催化降解率可高于80%.     

Supercritical Carbon Dioxide Fractionation of Anhydrous Milk Fat

Supercritical carbon dioxide was used to fractionate anhydrous milk fat. Six fractions were produced at 40, 50 and 60 °C using pressure values of 10, 20, 25, 30, 33 and 36 MPa. The fractions were analyzed for fatty acids, thermal behavior, iodine and color values. Composition and yield of fatty acid methyl esters were evaluated at different fractionation conditions in relation to the original milk fat values. Short chain fatty acids (C₄–C₈), medium chain fatty acids (C₁₀–C₁₄) and total saturated fatty acids were decreased from fraction obtained in the order of 10–36 MPa, while long chain fatty acids (C₁₆–C_18:2) and total unsaturated fatty acids were increased. Fractions obtained in the raffinate stage of the fractionation exhibited higher melting behavior that obtained at the low CO₂ pressures. The higher iodine value of raffinate fraction indicated that fraction was richer in oleic acid. Fractions produced at low pressures had lower melting behavior than those obtained at high pressures. Yellowness Index and b* values increased in raffinate fraction due to concentration of carotenoids.     

Foaming of Homogeneous Polypropylene and Ethylene-Polypropylene Block Copolymer Using Supercritical Carbon Dioxide

A new process was used to foam homogeneous polypropylene (HPP) and ethylene-polypropylene block copolymer (CPP). Many different foaming behaviors of these two kinds of PP were observed. The HPP and CPP were characterized by Differential Scanning Calorimetry (DSC), and Capillary Rheometry. We find that the melt shear viscosity of CPP is more sensitive to the temperature variation than that of HPP, thus leading to larger change of cell diameter of CPP with foaming temperature. Cell size of CPP is the result of competition between cell nucleation and cell growth. When the saturation pressure is lower or higher than 25 MPa, cell nucleation or cell growth plays a dominant role, which leads to the increase or decrease of cell size, respectively. Because of its low melting temperature and crystallinity, cell diameter of CPP increases with the infiltration temperature increasing, which is opposite to those of HPP. And at the foaming temperature of 152°C or 158°C, cell diameter of CPP increases or decreases with an increase in foaming time, while that of HPP decreases with foaming time increasing at both foaming temperatures.     

Dimensionless Empirical Model to Correlate Pharmaceutical Compound Solubility in Supercritical Carbon Dioxide

The accurate experimental determination of pharmaceutical compound solubilities at various temperature and pressure ranges in supercritical carbon dioxide (ScCO₂) is a challenging and time‐consuming task. Therefore, prediction or correlations of solute solubilities are essential for implementation of ScCO₂ technologies to pharmaceutical industries. Solubilities of 41 pharmaceutical compounds in ScCO₂ are correlated by an empirical model, which is developed based on the degree of freedom analysis. Its correlating ability is compared with existing solubility models elaborated by other authors and evaluated in terms of global mean absolute relative deviation, sum of squares due to error, root mean square deviation, R², and Adj. R². The proposed model is found to correlate better than existing models.     

超临界CO_2辅助UHMWPE/PP挤出成型研究

对超临界CO2辅助UHMWPE/PP共混体系的挤出成型进行了研究。结果表明,在挤出成型过程中,超临界CO2对UHMWPE/PP体系起到一定的增韧作用,使其力学性能有所改善。同时超临界CO2作为一种增塑剂,降低了UHMWPE/PP体系的黏度,改善了体系的流动性和加工性能。     

Bioactive Components of Commercial and Supercritical Carbon Dioxide Processed Wheat Germ Oil

Wheat germ oil (WGO) is a specialty product with a very high nutritional value. The chemical composition of both commercial and pilot scale supercritical carbon dioxide (SC-CO₂) processed WGO was examined. This study showed that methods used for oil extraction and refining did not have a significant effect on the fatty acid composition of the oil. SC-CO₂ extracted oil had a higher tocopherol content than that of commercially hexane extracted oil. The phospholipid content of the SC-CO₂ extracted oil was very low indicating that the SC-CO₂ extraction method could eliminate the degumming step from edible oil refining processes. Although the conventional chemical oil refining technique reduced the tocopherol content of the WGO, it was possible to concentrate tocopherols in WGO by using physical refining methods such as molecular distillation. Published with approval of the Director, Oklahoma Agricultural Experiment Station.     

超临界流体色谱法测定固体在二氧化碳中的溶解度

开发了一种测定超临界二氧化碳中大分子溶质的溶解度的方法。这一方法将微型超微界流体萃取直接与超临界色谱相耦合，超临界流体色谱采用ＦＩＤ作为检测器。实验中两者具有同一压力、温度及同样的ＣＯ２流速度。     

金属络合物在超临界CO_2中的溶解度研究

在温度为308.15～328.15 K、压力为10～30 MPa的条件下,用超临界萃取装置测定了8-羟基喹啉铅、8-羟基喹啉汞、二乙基二硫代氨基甲酸铅、二乙基二硫代氨基甲酸汞4种络合物在超临界CO2(SC-CO2)中的溶解度,分析了压力和温度对溶解度的影响.     

Nanocolumnar Preferentially Oriented PSZT Thin Films Deposited on Thermally Grown Silicon Dioxide

We report the first instance of deposition of preferentially oriented, nanocrystalline, and nanocolumnar strontium-doped lead zirconate titanate (PSZT) ferroelectric thin films directly on thermal silicon dioxide. No intermediate seed or activation layers were used between PSZT and silicon dioxide. The deposited thin films have been characterised using a combination of diffraction and microscopy techniques.     

Heterogeneous Catalysis in Supercritical Media: 1. Carbon Dioxide

Over the past few years, supercritical fluids have received considerable interest as reaction media. Supercritical fluids combine properties of gases and liquids. Densities are lower than in the liquid phase, but significantly higher than in the gas phase. This makes supercritical fluids excellent solvents for a variety of substances. The good dissolution capacity exists only in or near the supercritical range. Reaction products can be separated, for instance, simply by decreasing temperature and pressure. This may be used to intensify the process as complex separation processes, like distillation, are avoided.     

Column Fractionation of Canola Oil Deodorizer Distillate Using Supercritical Carbon Dioxide

Semi-continuous column fractionation of canola oil deodorizer distillate using supercritical CO₂ (SCCO₂) was carried out to determine the feasibility of value-added processing of this feed material for the recovery of bioactive components such as sterols and tocopherols and to determine the effect of operating conditions [pressure (20, 25 MPa using a temperature gradient of 70–100 °C), temperature (70, 100 °C) and a linear temperature gradient (70–100 °C at 25 MPa)] on extract yield and separation efficiency. Total extract yield increased significantly (p ≤ 0.05) with pressure, whereas at isobaric conditions (25 MPa) the highest yield was obtained at the lowest temperature tested (70 °C). Fractionation efficiency was reflected in the composition of fractions and was affected by operating conditions. Residue composition was determined by extract yield in addition to selectivity. Use of the thermal gradient (70–100 °C) decreased the content of volatiles, free fatty acids and tocopherols while increasing sterol content significantly (p ≤ 0.05) to a level of 40% (GC area %) in the residue obtained at 25 MPa. The findings indicate the potential of canola oil deodorizer distillate as a source of sterols and warrant further research on the countercurrent column fractionation to improve the separation efficiency.     

Hydrogenation of Nitrobenzene with Supported Transition Metal Catalysts in Supercritical Carbon Dioxide

Transition metal catalysts such as Pd, Pt, Ru, and Rh supported on carbon, silica and alumina have been examined for the hydrogenation of nitrobenzene (NB) in supercritical carbon dioxide (scCO₂) and in ethanol. The order of hydrogenation activity is Pt>Pd>Ru, Rh in scCO₂ and in ethanol. The effectiveness of the support is C>Al₂O₃, SiO₂ for either Pt or Pd in scCO₂. For all the catalysts, higher selectivity to aniline has been obtained in scCO₂ compared with ethanol. Hydrogenation of nitrobenzene catalyzed with Pd/C and Pt/C catalysts was successfully conducted in scCO₂ with a 100% yield to aniline at a lower reaction temperature of 35 °C. The product aniline (organic phase) can be easily separated from the side‐product water (aqueous phase), solvent (scCO₂), and catalyst (solid) by a simple phase separation process. The hydrogenation of NB is a structure‐sensitive reaction in ethanol as well as in scCO₂ except for a few Pt/C catalysts in which the degree of metal dispersion is small (<0.08).     

碳钢基体镍-磷合金镀层表面沉积TiO2薄膜

采用电沉积法在碳钢镀镍一磷合金镀层表面制备了TiO2薄膜,研究了溶液pH值、沉积时间和电流密度对薄膜增重的影响,分析测定了薄膜的成分及表面形貌。所得最佳工艺条件：pH值为4;时间为40min;电流密度为40-50mA／cm^2。在最佳工艺条件下成功制备了与基体结合良好、致密、均匀的TiO2薄膜。浸泡试验表明TiO2薄膜提高了镍一磷合金镀层在质量分数为10％硫酸和10％氯化钠溶液中的耐蚀性。