Experimental and Theoretical Study of Chemical Equilibria in the Reactive Systems of Acetals Synthesis

• Tipo: Artigo em Revista Científica Internacional
• Data: 2012

Autores

Silva, VMTM (Autor) Outra; Carla S.M. Pereira (Autor) FEUP; Alírio Rodrigues (Autor) FEUP; Verevkin, SP (Autor) Outra; Emel'yanenko, VN (Autor) Outra; Garist, IV (Autor) Outra; Gmehling, J (Autor) Outra

Revista

Título: Industrial & Engineering Chemistry Research

Vol. 51

Páginas: 12723-12729

ISSN: 0888-5885

Editora: American Chemical Society

Indexação

ISI Web of Knowledge - 1 Citação

Scopus - 1 Citação

Outras Informações

ID Authenticus: P-002-4HA

DOI: 10.1021/ie301484y

Abstract (EN): The chemical equilibria of acetals of acetaldehyde reactive systems (with methanol, ethanol, and n-butanol to form 1,1-dimethoxyethane, 1,1-diethoxyethane, and 1,1-dibuthoxyethane, respectively) were studied in the temperature range (293-333 K) in the liquid phase. The three reactive systems exhibit a strong nonideal behavior in the liquid phase. The knowledge of the activity coefficients is required to obtain the thermodynamic equilibrium constants K-a. The activity coefficients were estimated by the modified UNIFAC method, which already includes the parameters for the acetal group. The reaction enthalpies for the three acetalizations in the liquid phase were obtained from the temperature dependences of the corresponding thermodynamic equilibrium constants. These values were compared to those obtained by high-level ab initio calculations of the reaction participants using the Gaussian 03 program package. Absolute electronic energy values of the molecules have been obtained using G3(MP2) level. Using these results, calculated equilibrium constants and enthalpies of reaction of the acetals synthesis in the liquid phase based on the principles of statistical thermodynamics are found to be in acceptable agreement with the data obtained from the thermochemical measurements.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 7