低质量分数表面活性剂作模板合成 MCM-41中孔分子筛

以硅酸钠为硅源,表面活性剂十六烷基三甲基溴化铵(CTMABr)为结构模板剂,用水热晶化法在w(CTMABr)=1%～3%下制备全硅MCM-41中孔分子筛。采用染料吸附脱色实验比较了原料配比、反应体系pH值、晶化时间、晶化温度、脱模温度对MCM-41合成的影响。结果表明,合成MCM-41中孔分子筛时表面活性剂CTMABr质量分数必须达到1%以上;pH=10～12;晶化温度以125℃左右为好;前驱体脱模温度控制在600～800℃。在较优的工艺条件w(CTMABr)=1 5%、pH=11、晶化温度125℃、晶化时间24h、脱模温度640℃下得到了具有完美晶型结构、BET比表面积=1370m2/g、平均孔径3 28nm的全硅MCM-41中孔分子筛。

Synthesis of Silica Mesoporous Molecular Sieve MCM-41 Using Surfactant of Low Mass Fraction as Template

Mesoporous molecular sieve MCM-41 was prepared by hydrothermal crystallization reaction using low mass fraction (1%-3%) of cetyltrimethylammonium bromide(CTMABr) as structure template and sodium silicate as silica source.Influence of the process conditions was investigated by absorbing decoloring experiments.Proper process parameters were selected:content of CTMABr in the starting composition higher than 1 mass%, pH=10-12,crystallizing at ～125 ℃ for 24 h and calcining precursor to remove template at 600-800 ℃.Thus,under the optimized conditions:w(CTMABr)=15 mass%, pH=11,crystallizing temperature 125 ℃ for 24 h,and calcining temperature 640 ℃,silica mesoporous molecular sieve MCM-41 with good crystalline structure,average pore size of 328 nm and surface area (BET)=1371 m2/g was synthesized.