A serials of modified kaolinites were prepared by calcination and further acid treatment and characterized by in-situ XRD, N₂ adsorption, NH₃-TPD, Py-IR and ²⁷Al MAS-NMR. And their catalytic performance in pyrolysis of methanol/benzyl phenyl ether (MeOH-BPE), a model compound of low-rank coal, were investigated at 400 °C in a fixed-bed reactor to explore the correlation between the structure of modified samples and their catalytic performances. The results show that calcination temperature above 500 °C causes the collapse of kaolinite structure. Further acid leaching facilitates the formation of micropores and mesopores. The calcination of kaolinite leads to the transformation of six-coordinate Al atoms (Al^VI) into four and five coordinate species (Al^IV and Al^V), while the subsequent acid treatment increases the contents of Al^IV and Al^VI and removes Al^V. Total acid sites exhibit a first increase and then decrease tendency with the raising calcination temperature. In the presence of the modified kaolinites, BPE conversion significantly enhances and reaches the highest value of 91.41% over K-A-700 prepared by calcination at 700 °C of kaolinite and further acid leaching. Besides, the maximum content of phenol and toluene is also achieved due to the highest acid sites and Al^IV content of K-A-700, which favors the generation of ·H, thus resulting in an obvious inhibition of bibenzyl formation but a significant increase of 2-benzylphenol. In-situ pyrolysis by time-of-flight mass spectrometry suggests that the cleavage of C_al-O bond of BPE to form phenol radicals and benzyl radicals is the primary way, while insufficient ·H results in the formation of dominant product of 2-benzylphenol.

通过煅烧和进一步的酸处理来制备一系列的改性高岭石，并通过原位XRD，N ₂吸附，NH ₃ -TPD，Py-IR和²⁷ Al MAS-NMR进行表征。并在固定床反应器中于400°C下研究了它们在低级煤模型化合物甲醇/苄基苯基醚（MeOH-BPE）的热解中的催化性能，以探索改性样品与结构之间的相关性。它们的催化性能。结果表明，煅烧温度高于500°C会导致高岭石结构崩溃。进一步的酸浸促进了微孔和中孔的形成。高岭石的煅烧导致六配位的Al原子（Al ^VI）成四个和五个坐标物种（铝^IV和Al ^V），而随后的酸处理增加Al的含量^IV和Al ^VI和去除的Al ^V。随着焙烧温度的升高，总的酸位点呈现出先增加后减少的趋势。在改性高岭石的存在下，BPE转化率显着提高，与通过在700°C下煅烧高岭石和进一步酸浸制得的KA-700相比，BPE转化率达到91.41％的最高值。此外，由于最高的酸位和Al ^IV含量，苯酚和甲苯的含量也达到了最高。KA-700的含量，有利于·H的生成，因此导致联苄的形成受到明显的抑制，但2-苄基苯酚的显着增加。飞行时间质谱的原位热解表明，裂解BPE的C _al -O键形成酚自由基和苄基自由基是主要方法，而·H不足则导致形成2-的主导产物。苄基苯酚。