| X型沸石催化剂的甲苯甲醇侧链烷基化反应和吸附量热研究 |
| STUDIES OF SIDE CHAIN ALKYLATION OF TOLUENE WITH METHANOL AND MICROCALORIMETRIC ADSORPTION OVER X-TYPE ZEOLITE CATALYSTS |
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| 摘要: 本文报道了以原粉NaX和成型NaX为前体分别通过离子交换法及浸渍法制得的几种碱金属阳离子X型沸石上甲苯甲醇侧链烷基化反应的活性和选择性。并以NH3和CO2的微分吸附量热表征了这些催化剂的酸碱性。结果表明，在所有催化剂中成型KX的侧链反应活性最高。该催化剂对NH3的微分吸附热为45 kJ/mol左右，吸附覆盖度为3.3 μmol/m2；对CO2的微分吸附热在128～60 kJ/mol之间，吸附覆盖度为0.16 μmol/m2。对比其他三种酸性相近的催化剂，碱性更强(如K/KX(p)和K/KX(c))或更弱(如KX(p))时，侧链反应活性都较差。看来，成型KX催化剂的表面酸碱性匹配对侧链烷基化反应比较有利。该结果进一步证明了在甲苯甲醇侧链烷基化反应中催化剂酸碱协同作用的重要性。 |
| 关键词: X型沸石 甲苯侧链烷基化 NH3吸附量热 CO2吸附量热 表面酸碱性 |
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| Abstract: The side chain alkylation of toluene with methanol over several X-type zeolites, using powder NaX or commercial NaX as the starting materials respectively, then exchanged with alkali cations and/or further impregnated with KOH, was studied. The catalytic reactivities of these catalysts were correlated to their acidities and basicities, characterized by microcalorimetric adsorption of CO2 and NH3. It was found that of all the catalysts the commercial KX shows the highest activity. The differential heat and coverage are 128～65 kJ/mol and 0.16 μmol/m2 for CO2 adsorption; and 50 kJ/mol or so and 3.3 μmol/m2 for NH3 adsorption. Comparing to the other catalysts with the same acidity, the activity of the side chain alkylation is worse when the catalyst has a stronger basicity (such as K/KX(c) and K/KX(p)) or a weaker basicity (such as KX(p)). It seems that KX(c) has a proper acidity and basicity which is more favorable to this reaction than other catalysts studied in this work. This results further demonstrate that the coordination of acidity and bacisity on the catalyst is more important to the side chain alkylation of toluene with methanol. |
| Keywords: X-type zeolite side chain alkylation of toluene with methanol microcalorimetric adsorption of CO2 microcalorimetric adsorption of NH3 surface acidity and basicity |
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| 王文月,沈俭一,葛欣.X型沸石催化剂的甲苯甲醇侧链烷基化反应和吸附量热研究[J].无机化学学报,1998,14(3):322-326. |
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