Egyptian Petroleum Research Institute, Petrochemical department, Nasr City, Cairo 11727, Egypt.
Chemistry Department, Faculty of Science, Menofia University, Shibein El-Kom, Egypt.
Int J Biol Macromol. 2016 Oct;91:278-93. doi: 10.1016/j.ijbiomac.2016.05.053. Epub 2016 May 16.
The post synthesis of Al(3+) or Zr(4+) substituted MCM-48 framework with controlled acidity is challenging because the functional groups exhibiting acidity often jeopardize the framework integrity. Herein, we report the post-synthesis of two hierarchically porous MCM-48 composed of either aluminum (Al(3+)) or zirconium (Zr(4+)) clusters with high throughput. All prepared catalysts have been characterized by HR-TEM, XRD, IR, N2-adsorption, NH3-TPD, TGA and MAS NMR. They exhibit BET surface areas of 597 and 1112m(2)g(-1) for 8.4% Al/MCM-48 and 2.9% Zr/MCM-48, respectively. XRD analysis reveals that the hierarchical porosity of parental MCM-48 is reserved even after incorporation of Al(3+)or Zr(4+). Zr/MCM-48 catalysts are demonstrate a superior performance versus that of Al/MCM-48 and MCM-48 because of the mild (ZrO2) or nil (SiO2) Lewis acidity contributed from Zr-μ2-O group as well as smaller pore sizes suitable for the restriction of unwanted side reactions. The reaction conditions which were affecting the catalytic pyrolysis and final products were gas flow rate, pyrolysis temperature, and catalyst to lignin ratio. A total of 49% of BTX product were obtained over 2.9% Zr/MCM-48 at 600°C. The Lewis acid character was the governing factor which helps in pyrolysis and directly affects the BTX formation.
后合成的 Al(3+)或 Zr(4+)取代的 MCM-48 骨架具有可控酸度，这是具有挑战性的，因为表现出酸度的官能团常常危及骨架的完整性。在此，我们报告了两种具有高吞吐量的由铝（Al(3+))或锆（Zr(4+))簇组成的分级多孔 MCM-48 的后合成。所有制备的催化剂均通过 HR-TEM、XRD、IR、N2-吸附、NH3-TPD、TGA 和 MAS NMR 进行了表征。它们分别具有 597 和 1112m(2)g(-1)的 BET 表面积，用于 8.4% Al/MCM-48 和 2.9% Zr/MCM-48。XRD 分析表明，即使在引入 Al(3+)或 Zr(4+)后，母体 MCM-48 的分级孔隙率也得以保留。Zr/MCM-48 催化剂表现出优于 Al/MCM-48 和 MCM-48 的性能，这是由于 Zr-μ2-O 基团贡献的温和（ZrO2)或零（SiO2)路易斯酸度以及适合限制不需要的副反应的较小孔径。影响催化热解和最终产物的反应条件是气体流速、热解温度和催化剂与木质素的比例。在 600°C 下，2.9% Zr/MCM-48 可获得 49%的 BTX 产物。路易斯酸性是帮助热解的控制因素，直接影响 BTX 的形成。
