Syntheses of diphenylmethane derivatives on solid acid catalysts with controlled hydrophobicity, acidity, and reaction space

从绿色化学的观点来看，均相催化剂在化学品合成中的多相化具有重要意义。本研究的目的是寻找合适的固体酸催化剂用于以下三个反应：(1)由甲醛和苯酚合成双酚F，(2)由甲醛和2，6-二甲基苯酚合成双(4-羟基-3，5-二甲基苯基)甲烷，(3)由甲醛和苯胺合成双(4-氨基苯基)甲烷。考察了不同类型的沸石分子筛和介孔硅酸铝分子筛(Al-MCM-41)。所有反应均在常压下的液相中进行。以商品苯酚、2，6-二甲基苯酚、苯胺和福尔马林为原料，不经提纯。研究表明，由于甲醛具有较高的反应活性，弱酸中心是三个反应的主要原因，并且每个反应的催化剂和反应条件都是合适的。也就是说，对于反应(1)合适的催化剂是高硅H-β沸石和Al-MCM-41，需要较高的苯酚/甲醛比才能获得高的选择性；对于反应(2)合适的催化剂是Al-MCM-41，在任何反应物比下，选择性几乎都是100%；

Catalyst heterogenization in syntheses of chemicals by homogeneous catalyses is important from the viewpoint of green chemistry. The purpose of this study is to find suitable solid acid catalysts for the following three reactions in which homogeneous catalysts are used in practical processes:(1) Synthesis of bisphenol F from formaldehyde and phenol, (2) Synthesis of bis(4-hydroxy-3, 5-dimethylphenyl)methane from formaldehyde and 2, 6-dimethylphenol, (3) Synthesis of bis(4-aminophenyl)methane from formaldehyde and aniline. The catalysts examined were various types of zeolite and mesoporous aluminosilicate molecular sieves(Al-MCM-41). All the reactions were carried out in liquid phase at atmospheric pressure. Commercial phenol, 2, 6-dimethylphenol, aniline, and formalin were used as reactants without purification. It is clarified in this study that weak acid sites are responsible for three reactions because of a high reactivity of formaldehyde and the following catalysts and reaction conditions for each reaction are suitable. That is, for reaction (1) the suitable catalysts are high silica H-beta zeolite and Al-MCM-41 and a high phenol/formaldehyde ratio is required to attain a high selectivity, for reaction (2) the suitable catalyst is Al-MCM-41 and the selectivity is almost 100% at any reactant ratios, and for reaction (3) the active catalysts are Al-MCM-41 and H-beta and USY zeolites, the selectivity is affected by reaction spaces, and USY exhibits the highest selectivity.