催化氢酯基化反应的研究进展

介绍了氢酯基化反应及其特点,分别综述了均相催化氢酯基化反应和多相催化氢酯基化反应的研究现状,并对不对称催化氢酯基化的研究提出了建议。     

Palladocarbosilane dendrons in supercritical carbon dioxide. Catalytic behaviour in the asymmetric hydrovinylation of styrene

The palladocarbosilane dendrons 1 and 2, containing the P-stereogenic phosphine fragment at the focal point are soluble in supercritical CO₂ medium and capable to catalyze the asymmetric hydrovinylation of styrene with good activity and enantiomeric excesses.     

岩蔷薇超临界二氧化碳萃取研究

采用超临界二氧化碳萃取技术 ,研究了岩蔷薇的萃取工艺。探讨了温度、压力、时间及CO2 流量等因素对萃取物得率的影响 ,采用四因素四水平的正交设计 ,得出超临界二氧化碳萃取最佳工艺条件为 :压力 2 8MPa、温度 40℃、时间 3h、流量 3 0L/h ,萃取物得率为 6.6%。产品质量优于有机溶剂萃取法。     

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。     

超临界二氧化碳中的胶束催化技术进展

介绍了超临界二氧化碳(scCO2)胶束催化技术的研究进展：scCO2胶束及其相特征、CO2表面活性剂及scCO2胶束催化技术的应用与工艺开发。scCO2胶束及其相特征对于设计高效的亲CO2表面活性剂及研究scCO2胶柬催化作用具有重要指导意义。scCO2胶束的相特征主要是温度、压力和胶束含水比的函数。指出了开发亲CO2表面活性剂的一些基本原则,其中降低表面活性剂在H2O／CO2表面的界面张力和提高活性剂的吸附能力要比提高溶解度更为重要。scCO2胶束催化技术可以明显提高催化反应活性,适合于开发原位分离反应工艺。建议加强scCO2胶束催化技术的研究及相关工艺开发。     

二氧化碳在化学合成中的应用

二氧化碳是有机物氧化的最终产物,如何将其转化为有用的化工资源,十分重要.综述了近年来二氧化碳在合成及制备高附加值化工原料等方面的进展.     

天然香料植物的超临界CO2萃取及应用问题

本文结合我国天然香料植物资源的利用情况及超临界流体技术在天然香料植物提取方面的应用和存在的问题进行讨论。提出为加快我国天然香料资源的利用 ,发展边远地区的经济和香料经济作物的种植 ,应充分发挥联合的优势 ,应用新技术 ,开发新产品 ,提高资源的利用率和经济效益     

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。     

Pd-catalyzed allylic amination in supercritical carbon dioxide: Synthesis of carborane-containing terpenoids

Pd-catalyzed amination of allylic carbonates with N-(ortho-carboran-3-yl)-N-methylamine was carried out in supercritical CO₂. It has been demonstrated that complete conversion of allylic carbonates to the corresponding carborane amines with excellent regioselectivity may be achieved in scCO₂ (170 atm, 60 °C) using NaHCO₃ as the acceptor base. The reaction offers a selective method for the preparation of allylic amines and provides a useful approach to new terpenoids.     

超临界二氧化碳萃取器萃取分离香茅油

本文介绍了利用现有１５０Ｌ高压釜（压力２０ＭＰａ）改造的超临界二氧化碳萃取器萃取分离香茅油,探讨了压力、温度、时间对萃取分离效果的影响。结果表明,采用超临界二氧化碳萃取器萃取分离香茅油时应选择一个适宜的压力、温度和萃取时间,产品的色、香味、纯度均优于常规的减压蒸馏法。     

超临界二氧化碳中的不对称合成研究进展

主要介绍了超临界二氧化碳中的不对称合成反应,如不对称氢甲酰化反应、碳-碳双键的不对称催化氢化、亚胺不对称催化还原、烷基化反应、不对称D-A反应、醇醛缩合反应、不对称酶催化反应等的研究现状,同时对离子液体与超临界二氧化碳构成的混合介质中的不对称合成研究进展作了介绍,对这一领域中若干基本问题的研究发展趋势进行了分析讨论。     

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.     

超临界CO2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。     

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.     

超临界二氧化碳萃取蛋黄油实验研究

介绍了超临界二氧化碳萃取技术提取蛋黄洫的工作原理及工艺流程。设计了正交实验.考察萃取压力、萃取温度、萃取时间等参数对萃取率的影响,确定了最佳工艺条件。     

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.     

Polymerization of acrylonitrile in supercritical carbon dioxide

A series of fluorinated diblock copolymers, consisting of styrene (St)-acrylonitrile (AN) copolymer [poly(St-co-AN)] and poly-2-[(perfluorononenyl)oxy]ethyl methacrylate, with various compositions as well as with different molecular weights were synthesized by atom transfer radical polymerization and characterized. Dispersion polymerization of acrylonitrile in supercritical carbon dioxide (scCO₂) at 30 MPa and at 65 °C with this kind of amphiphilic block copolymer as a stabilizer and 2,2′-azobisisobutyronitrile as an initiator was investigated. The experimental results indicated that, in the presence of a small amount of poly(St-co-AN) (5 wt% to AN), spherical particles of polyacrylonitrile (PAN) were prepared with small diameter and narrow polydispersity (d_n = 153 nm, d_w/d_n = 1.12), resulting from the high stabilizing efficiency of this fluorinated block copolymer. Furthermore, the polymerization of AN in scCO₂ under different initial pressures especially under low pressure (<14 MPa) was studied. When the polymerization was carried out around the critical pressure of CO₂ (7.7-7.8 MPa), the PANs with high molecular weight (M_ν ≈ 130,000-194,000) were synthesized at high monomer conversion (>90%) no matter whether the stabilizer was added, compared to those synthesized by dispersion polymerization at 30 MPa. It was also found that the crystallinity of PAN synthesized at 7.7-7.8 MPa was somewhat higher than that synthesized at 30 MPa, while its crystallite size did not change.     

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。