Molecular simulation on carbon dioxide fixation routes towards synthesis of precursors for innovative urethanes

Abstract

Classical molecular dynamics were carried out in order to obtain insights into proper conditions to perform chemical fixation of carbon dioxide (CO 2 ) with epoxide molecules into cyclic carbonates. Two different molecules containing epoxide groups were investigated: 1,2-Epoxybutane (EB), called linear aliphatic epoxide molecule, and 3-Ethyl-7-oxabicyclo(4.1.0)heptane (EC), called cycloaliphatic epoxide molecule. The reaction systems involving carbon dioxide additionally were catalyzed by tetraethylammonium bromide (TEAB). The dynamics of the molecular groups were studied by taking into account known reaction mechanisms to investigate whether the optimal reaction conditions were observed. Radial distribution functions and self-diffusion coefficients were calculated and revealed that in case of the systems with cycloaliphatic epoxide groups as reagent the CO 2 molecules were located far away from the agglomerate formed by the dispersed tetraethylammonium bromide catalyst and epoxide groups (EC), and they do not present enough mobility to overcome the long distances to react. Additionally, it was observed that, in the case of the linear aliphatic epoxide groups (EB), the dynamics of the groups tends to facilitate the reaction mechanisms by presenting a considerable amount of available CO 2 molecules in the neighborhood of the epoxy rings. Thus, via the Molecular Dynamics insights, the systems containing linear aliphatic epoxide groups presented a much more accessible condition for the subsequent reaction steps of the carbon dioxide fixation to occur as compared to systems containing cycloaliphatic epoxide groups. The simulation results are in agreement with the experimental findings, which showed via infrared spectroscopy the successful conversion of epoxy rings from linear aliphatic epoxide molecules into five-membered cyclic carbonates after reacting with carbon dioxide.

A Molecular Dynamics Simulation of the Toluene-Water Interface in the Presence of an External Magnetic Field

“…The number of surrounding atoms in vicinity of atom interest is called the coordination number which can be introduced here by integration RDF. (Carrillo Beber et al 2015). We calculated the area under the RDF plot and reported the integration RDF in Fig.…”

Materiais híbridos obtidos via fixação de CO>sub<2>/sub< com potencial para serem empregados como biomateriais: obtenção de compósitos de poli(hidroxiuretana)s derivadas de polidimetilsiloxano com fosfato de

“…Deste modo, apontando que a metodologia de purificação com acetato de etila e água foi eficiente em remover o catalisador TEBA. O espectro de FTIR do CCPDMS na Figura 21 apresenta uma banda na região de 1800 cm -1 que é característico de carbonilas de ciclocarbonato (AGUIAR et al, 2014;CARRILLO BEBER et al, 2015). Por outro lado, essa banda não está presente no espectro do EPDMS.…”