活性炭模板制备的多孔固体碱催化酯交换反应  

Preparation of Porous Solid Bases with Active Carbon as Template and Their Use as Catalyst in Transesterification

作　　者：刘水刚[1] 黄世勇[1] 李军平[1] 赵宁[1] 魏伟[1] 孙予罕[1] 

机构地区：[1]中国科学院山西煤炭化学研究所

出　　处：《石油化工》2007年第12期1250-1254,共5页Petrochemical Technology

摘　　要：以活性炭为模板制备出了多孔固体碱。通过将相应的前体盐溶液浸渍到经适当预处理的活性炭中,并在真空或惰性气氛中加热,使前体分解,再经焙烧除去活性炭,使产物基本保留了活性炭的多孔形貌特征。采用X射线衍射、扫描电子显微镜、CO2程序升温脱附、热重分析和BET法对多孔固体碱进行了表征。表征结果显示,多孔固体碱具有发达的孔道结构和较高的比表面积,经600℃焙烧后,多孔CaO和多孔MgO的比表面积可分别达139,178m2/g;多孔CaO和MgO的碱强度与常规CaO和MgO基本一致。将制备的多孔固体碱用于甲醇与碳酸丙烯酯酯交换合成碳酸二甲酯反应时,多孔固体碱的催化性能好于常规固体碱,可减少催化剂用量,缩短反应时间,提高反应效率。Porous solid bases such as porous CaO and porous MgO were prepared by employing active carbon as hard template. The active carbon was impregnated in precursor salt solutions of CaO and MgO in advance and then the salts decomposed in vacuum or inert gas at high temperatures. Porous framework of active carbon was successfully retained in the products. The samples were characterized by means of XRD, SEM, CO2 - TPD,nitrogen adsorption and TG. After calcinations at 600 ℃ ,porous CaO and MgO possess fairly high specific surface areas of 139 m^2/g and 178 m^2/g, respectively. The porous structures are remarkably favorable to diffusions of both reactant and product molecules. Results of CO2 -TPD prove that porous solid bases possess strong basicity and high basic intensity, equivalent to conventional solid base. The porous solid bases are used as catalysts in transesterification of methanol and propylene carbonate for synthesis of dimethyl carbonate. Their catalytic activities are much higher than conventional MgO and CaO.

关 键 词：活性炭 多孔材料 固体碱 催化 酯交换 

分 类 号：TQ032.41[化学工程]