Cluster model DFT study of lactic acid dehydration over Fe and Sn-BEA zeolite

Izabela Czekaj,Natalia Sobuś

doi:10.5267/j.ccl.2019.5.002

Abstract

Cluster model DFT study of lactic acid dehydration over Fe and Sn-BEA zeolite

Highlights

The urgent need for more sustainable production of chemicals from renewable feedstock, like biomass, have resulted in intensive research efforts in the search for novel porous nano-materials.[1]
The electronic structure of all clusters was calculated by ab initio density functional theory (DFT) methods using the non-local generalized gradient corrected functionals according to Perdew, Burke, and Ernzerhof (RPBE), in order to account for electron exchange and correlation
The energy level of acrylic acid above Fe-BEA has been found to be lower than the energy level of lactic acid (-0.38eV for the ‘ideal’ model and -0.8eV for the ‘hierarchical’ model, Figure 7 (4’) and Table 3)

Summary

Introduction

The urgent need for more sustainable production of chemicals from renewable feedstock, like biomass, have resulted in intensive research efforts in the search for novel porous nano-materials.[1]. Iron-exchanged zeolites (ZSM-5 and BEA) are an active catalyst for a large number of reactions, of which the selective catalytic reduction (SCR) of nitrogen oxides with ammonia or hydrocarbons,[11,12,13,14,15,16] the N2O decomposition reaction 17,18 and oxidation processes[19,20,21,22] are the most important. We are interested in designing a new theoretical approach for the synthesis of acrylic acid (AA) from lactic acid (LA) over zeolite catalysts. Lactic acid adsorption and dehydration toward acrylic acid processes have been studied in BEA zeolite. The tin and iron dimers are considered in the present studies as active sites for lactic acid adsorption

Computational details

Geometrical model

Metal dimers stabilization in the BEA- framework

Conclusions