This paper is interested in mechanism of lactic acid (LA) adsorption and dehydration into acrylic acid (AA) over tin and iron beta zeolite (Sn- and Fe-BEA) catalysts. The electronic structure of clusters was calculated by ab initio density functional theory (DFT) method. The M₂Si₁₂O₃₉H₂₂ (hierarchical zeolite) and M₂Si₂₂O₆₄H₃₂ (ideal zeolite) clusters (M=Al, Si, Sn) were used in the LA dehydration reaction. The stabilization of the dimeric complex M-O_b-M (where M= Sn or Fe) in the BEA, ideal and hierarchical structure, was investigated. Possible modes of interaction of lactic acid with different cations (Si, Al, Fe or Sn) in the BEA zeolite framework as well as with added iron and tin dimers were considered. The interaction of lactic acid was only observed above the M-O_b-M dimer. The direct mechanism of lactic acid dehydration into acrylic acid was found over metal M-O_b-M dimers deposited at the BEA zeolite.

Nowadays the use of fossil fuels as a non-renewable energy source has become a major challenge because of the pollution and the environmental impact. Substitution of biomass as an energy source and its supply chain design is the main question. Because of difficulties such as supply chain complexity, uncertainty in variables and selecting the site of bio-refineries many studies have been conducted in this regard. Studies in the field of biomass and biofuel production are described and classified. Also the strategic decisions such as choosing the sites, selecting energy conversation technology, ensuring economic, environmental, technical, and social sustainability and tactical decisions including allocating resources to productive plants, selecting transport modes, and types of warehouses are addressed in the reviewed papers. We have reviewed 140 papers in the interval between 1997 and 2016 and classified them based on the objective functions. The articles are classified based on their being single or multi objectivity, linearity or nonlinearity. Finally, a classification based on the regions in which the studies have been done.