β-Cyclodextrin-promoted synthesis of 2-phenylbenzimidazole in water using air as an oxidant

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 167; no. 1; pp. 349 - 354
• Main Authors: Ji, Hongbing, Huang, Liquan, Shen, Haimin, Zhou, Xiantai
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier B.V 15-02-2011; Elsevier
• Subjects: 2-Phenylbenzimidazole; air; Applied sciences; benzaldehyde; Catalysis; Catalytic reactions; Chemical engineering; Chemistry; energy; Exact sciences and technology; General and physical chemistry; oxidants; Oxidation; Reactors; temperature; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; β-Cyclodextrin; β-Cyclodextrin; Oxidation; Catalysis; 2-Phenylbenzimidazole; Steric hindrance; Oxidant; Catalyst
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2010.12.084

β-Cyclodextrin-promoted conversion of
o-phenylenediamine and benzaldehyde to 2-phenylbenzimidazole is described using air as an oxidant. Various factors including reaction temperature, amount of β-cyclodextrin, different feed sequences and different steric hindrances of benzaldehydes were investigated. The observed results are rationalized on the basis of binding modes of inclusion of substrates inside the β-cyclodextrin cavity and find strong support from energy minimization studies and
1H NMR. In this paper β-cyclodextrin blocked the smooth conversion while enhanced the selectivity. This is the first example to use β-cyclodextrin as a catalyst in water to restrain the conversion while improving the selectivity.