abstract
Ionic polymolybdate hybrids (IPH) are interesting catalysts for liquid phase olefin epoxidation with tert-butylhydroperoxide; (tbhp), e.g. conversion of terpenic and fatty acid methyl ester (FAME) components of biomass to useful bio-products. IPHs may be easily prepared, under clean, mild, aqueous phase conditions. The type of organic precursor and the synthesis conditions influence the structural features of the IPHs. In this work, IPH epoxidation catalysts possessing one- (1-D) or two-dimensional (2-D) structures were investigated, which included the new materials 1-D methylanunoniurn ammonium trimolybdate [Mo3O10 center dot CH3NH3 center dot NH4] (1) and 2-D bis(2,5-dimethylanilinium) pentamolybdate [Mo5O16 center dot 2(NH3C6H3(CH3)(2))] (4) with solved structures, and 1-D bis (3,5-dimethylanilinium) trimolybdate [Mo3O10 center dot 2(NH3C6H3(CH3)(2))] (2), bis(4-methylanilinium) trimolybdate [Mo3O10 center dot 2(NH3C6H4CH3)] (3), 2-D bis(anilinium) pentamolybdate [Mo5O16 center dot 2(NH3C6H5)] (5), bis(4-methylanilinium) pentamolybdate [Mo5O16 center dot 2(NH3C6H4CH3)] (6) and bis(4-ethylanilinium) pentamolybdate [Mo5O16 center dot 2(NH3C6H4C2H5)] (7). Systematic characterisation and catalytic studies helped gain insights into structure-activity relationships. The best-performing catalyst (2) was effective for the epoxidation of the FAMEs such as, methyl oleate which gave 92% methyl 9,10-epoxyoctadecanoate yield, at 99% conversion, at 70 degrees C. The reaction conditions (temperature, type of cosolvent and oxidant) influenced the catalytic reaction. Catalytic performance in consecutive batch runs was steady, and the structural features were essentially preserved.
keywords
OXYGEN-ATOM-TRANSFER; MOLYBDENUM(VI) COMPLEXES; DIOXOMOLYBDENUM(VI) COMPLEXES; ALTERNATING COPOLYMERIZATION; STRUCTURAL-CHARACTERIZATION; HYDROGEN-PEROXIDE; CRYSTAL-STRUCTURE; VEGETABLE-OILS; METHYL OLEATE; OXIDATION
subject category
Chemistry; Environmental Sciences & Ecology
authors
Bozek, B; Neves, P; Lasocha, W; Valente, AA
our authors
Anabela Tavares Aguiar Valente
Principal Researcher
Patrícia dos Santos Neves
Assistant Researcheracknowledgements
This work was developed in the scope of the project CICECO - Aveiro Institute of Materials [POCI-01-0145-FEDER-007679] financed by national funds through the Fundacao para a Ciencia e a Tecnologia (FCT) [ref. UID/CTM/50011/2013] and Ministerio da Educacao e Ciencia (MEC) and when applicable, cofinanced by Fundo Europeu de Desenvolvimento Regional (FEDER) under the PT2020 Partnership Agreement. The FCT and the European Union are acknowledged for a post-doctoral grant to P.N. [SFRH/BPD/110530/2015], cofunded by Ministerio da Ciencia, Tecnologia e Ensino Superior (MCTES) and the European Social Fund through the program Programa Operacional Potencial Humano (POPH) of Quadro de Referencia Estrategica Nacional (QREN). The European Union Erasmus + programme [project number: 2016-1-PL01-KA103-023786] is acknowledged for providing scholarship (financial support) for the traineeship.