两种甲酯化法比较微波辅助及超临界CO2提取琼榄果实油的成分

以南药琼榄果实为原料,采用微波辅助提取法(MAE)和超临界CO2提取法(SFE-CO2)提取琼榄果实油,并用气-质联用仪(GC-MS)比较了琼榄油经碱催化和BF3-MeOH催化甲酯化后的脂肪酸成分及其相对质量分数。结果表明,两种方法所提取琼榄油的脂肪酸成分大致相同。GC-MS分析MAE(碱催化法)、SFE-CO2(碱催化法)、MAE(BF3-MeOH催化法)、SFE-CO2(BF3-MeOH催化法)这4种方法所得的琼榄果实油,其中相对质量分数最高的是十八碳烯酸(69.44%、69.04%、64.92%、64.69%),次之为棕榈酸(20.82%、21.01%、21.45%、21.70%),再次是亚油酸(6.33%、6.03%、6.33%、6.13%)。不饱和脂肪酸占脂肪酸总量分别高达76.75%、75.91%、74.77%、74.30%。     

Contribution of agro‐waste material main components (hemicelluloses,cellulose, and lignin) to the removal of chromium (III) from aqueous solution

BACKGROUND: Agro‐waste materials can be used as biosorbents of heavy metals in aqueous solution. However, it is necessary to further study the contribution of agro‐waste materials components (i.e. hemicelluloses, cellulose, and lignin) to the heavy metal ions removal from aqueous solution to better understand the biosorption mechanism, and also based on the biosorbents main components, to predict their potential to remove heavy metals. RESULTS: Cellulose is contained in major proportion (greater than 46%) in the agro‐waste materials reported herein compared with hemicelluloses (from 12% to 26%), lignin (varying from 3% to 10%), and other compounds (22% to 30%) that were removed after the neutral detergent fiber procedure. The identified functional groups in agro‐waste materials and their fractions included hydroxyl, carboxyl, and nitrogen‐containing compounds. Lignin contributed in higher proportion than hemicelluloses to Cr (III) adsorption capacity in both sorghum straw and oats straw. On the other hand lignin was the main fraction responsible for Cr (III) adsorption in agave bagasse. CONCLUSION: Hemicelluloses and lignin were the main contributors to Cr (III) removal from aqueous solution, and cellulose contained in the agro‐waste adsorbents studied did not seem to participate. Copyright © 2009 Society of Chemical Industry     

Low‐temperature clean preparation of poly(lactic acid) foams by combining ethyl lactate and supercritical CO2: correlation between processing and foam pore structure

This study reports the low‐temperature and clean fabrication of porous poly(lactic acid) (PLA) through solid‐state foaming using various mixtures of ethyl lactate (EL) and supercritical CO₂ (scCO₂) as the blowing agent. Results showed that adding a small amount of EL (up to 0.2% molar fraction) to scCO₂ enhanced the plasticizing effect of the blowing agent mixture. As a direct consequence, at an operating temperature of 35 °C, PLA foams could be manufactured with homogeneous morphology, density as low as 0.09 ± 0.01 g cm^?3, mean pore sizes up to 519.0 ± 205.0 µm and pore densities in the range 2.0 × 10⁵ to 3.4 × 10⁸ pores cm^?3. Conversely, at a temperature of 40 °C, an increase of plasticizer concentration in the blowing agent mixture up to 0.2% promoted the crystallization of the polymer during sorption stage and, consequently, foaming was slightly reduced. © 2013 Society of Chemical Industry     

Silica Supported Sodium Hydrogen Sulfate and Amberlyst‐15: Two Efficient Heterogeneous Catalysts for Facile Synthesis of Bis‐ and Tris(1H‐indol‐3‐yl)methanes from Indoles and Carbonyl Compounds[1]

Bis‐ and tris(1H‐indol‐3‐yl)methanes are synthesized in high yields by an electrophilic substitution reaction of indoles with carbonyl compounds under mild reaction conditions using two efficient heterogeneous catalysts, silica supported sodium hydrogen sulfate (NaHSO₄⋅SiO₂) and amberlyst‐15. The second catalyst can be reused.