新型Brønsted-Lewis双酸位碳基固体酸的制备及其催化生物柴油的合成

以羧甲基纤维素钠（CMC）与硫酸铁螯合反应生成的螯合物为碳前驱体，以浓硫酸为磺化试剂，制备新型碳基固体酸催化剂。采用红外（FT-IR）、X射线衍射（XRD）、吡啶红外、扫描电子显微镜（SEM）、热重分析仪（TGA）、能谱仪（EDS）对催化剂进行表征。结果表明，该催化剂同时具有Brønsted和Lewis酸位点，是具有双酸位的碳基固体酸催化剂。将其应用到油酸与甲醇的酯化反应制备生物柴油体系中，考察了不同反应条件对油酸转化率的影响。在反应温度为70℃，反应时间为6h，油酸与甲醇物质的量比为1：10，催化剂用量为油酸质量7.5%条件下，油酸的转化率可达到96.8%。此外，对该催化剂的稳定性进行研究发现该催化剂有着良好的重复使用性和疏水性。

Preparation and application of a novel carbon-based solid acid with Brønsted-Lewis double acid sites for synthesis of biodiesel

A novel carbon-based solid acid catalyst was prepared with chelates of sodium carboxymethyl cellulose and iron sulfate as a carbon precursor, and with concentrated sulfuric acid as sulfonation agent. The physical and chemical properties of prepared catalyst were characterized by Fourier transform infrared (FT-IR), X-ray diffraction (XRD), pyridine-FTIR, scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and energy dispersive spectroscopy (EDS). It was used to catalyze the esterification of oleic acid with methanol to prepare biodiesel, and the influence of different reaction conditions on the conversion of oleic acid was investigated. The results show that the catalyst is a solid acid one with both Lewis and Brønsted acid sites. The conversion of oleic acid reaches 96.8% at the reaction temperature of 70℃, the reaction time of 6 h, the molar ratio of oleic acid to methanol of 1:10, and the catalyst dosages of 7.5% based on oleic acid. In addition, the stability performance of the catalyst tested indicates that the catalyst has a good reusability and hydrophobicity.