摘要
以氯磺酸为磺化试剂,与Al-MCM-41（AlM）及硅烷化后Al-MCM-41（SiAlM）介孔分子筛进行接枝磺化反应,分别得到SO3H/Al-MCM-41（SAlM）和SO3H/SiAl-MCM-41（SSiAlM）。采用X射线衍射（XRD）、N2吸附-脱附、NH3程序升温脱附（NH3-TPD）、热重分析（TG/DTA）、表面元素分析（EDS）等手段对产物结构和性能进行了分析表征。研究结果表明,当AlM与氯磺酸在三氯甲烷中回流3 h时,产物SAlM中S原子分率为0.42%。同样条件下,硅烷化后的SiAlM与氯磺酸反应,产物SSiAlM中S原子分率为2.40%。此时SAlM和SAlM的NH3-TPD酸量分别达到1.26 mmol/g和2.28 mmol/g,且均出现两个NH3脱附峰（T=150~200℃,T=500~520℃）,对应弱酸和强酸中心。XRD分析结果表明,SAlM和SSiAlM仍然保持六方介孔结构特征,并具有良好的结构对称性。SAlM和SSiAlM比表面积分别为815.2 m2/g和944.5 m2/g,平均孔径均为3.2 nm。SSiAlM在催化乙二醇硬脂酸酯反应中表现出很高的催化活性,当醇酸物质的量比为1.2：1.0,反应时间为1.0 h,催化剂用量为5%时,酯化率达到96%,且重复使用三次酯化率仍可达到73%。
Mesoporous Al-MCM-41（AlM） and silanized Al-MCM-41（SiAlM） were prepared through hydrothermal method and functionalized using chlorosulfonic acid. The sulphonic acid groups are covalently bonded to the surface of MCM-41 by etherification of Si-OH with chlorosulfonic acid reaction to obtained SOsH/Al-MCM-41 （SAlM） and SOsH/SiAl-MCM-41（SSiAlM） respectively. The structures and properties of the products were analyzed by X-ray diffraction （XRD）, N2 adsorption-desorption, NHs programmed temperature desorption （NH3-TPD）, surface of elemental analysis （EDS） and thermogravimetric analysis （TG/DTA）. The results showed that S percentage grafting on the surface of AlM reached 0.42% when AlM was refluxed for 3 h with chlorosulfonic acid in chloroform. Under the same conditions, S percentage grafting on the SiAlM reached 2.40%. NHs-TPD acid content of SAlM and SAlM were 1.26 mmol/g and 2.28 mmol/g respectively, and both give two NHs desorption peak （150-200 ℃, 500-520 ℃） corresponding to weak and strong acid center. XRD analysis results showed that SAlM and SSiAlM remained hexagonal mesoporous structure with good symmetry. The specific surface area SAlM and SSiAlM were 815.2 m2/g and 944.5 m2/g, average pore size of 3.2 rim. SSiAlM exhibited high catalytic activity in glycol stearate reactions. The esterification rate of stearate can have been 96% when molar ratio of glycol to stearate was 1.2, reaction time 1.0 h and 5% catalyst content. The esterification of 73% can be remained when SSiAlM was reused fourth time.
出处
《化学反应工程与工艺》
CAS
CSCD
北大核心
2011年第5期412-417,共6页
Chemical Reaction Engineering and Technology
基金
黑龙江省自然科学基金(B201010)
