Molecular Design of Solvents for Sustainable Chemical Processes

J. SCILIPOTI; M. CISMONDI; E. BRIGNOLE

Puerto Iguazú

Conferencia; 13th International Conference on Properties and Phase Equilibria for Products and Process Design (PPEPPD 2013); 2013

The second generation raw materials for renewable chemical products and biofuels are based on the use of biomass , mainly from ligno-cellulosic sources. Many challenging separations problems are faced for the conversion of cellulosic materials in fuels and chemicals. Even though there are different wood processing, in the present work we focus mainly on the process of detoxification of hydroxilates; that will be used for the production of ethanol and other chemicals by fermentation processes. In this work, the ECOFAC molecular design of solvents program (Cismondi and Brignole [1]) is upgraded to deal with the separation of organic chemicals found in wood hydroxilates, that are toxic for the fermentation process. For this purpose, the ECOFAC model is extended to cover the prediction and computer aided synthesis of associating compounds based on the A-UNIFAC model [2] and the extension of the molecular synthesis algorithm to complex aromatic compounds. The predictions of the ECOFAC program of pure component physical properties, boiling points, critical properties and densities based on UNIFAC groups is revised as well as the prediction of pure components viscosities. Examples of selection of solvents for different toxic components are presented and a strategy, for solvent selection with multiple objetive optimization goals, is presented. The ECOFAC program is also updated for the prediction of environmental properties, among others: octanol ? water partition coefficients and water solubilities of organic compounds. The program also incorporates a more general molecular design procedure to generate families of lignocellulosic derivatives that are toxic for the fermentation process. In this way potential solvents can be screened in their capacity to separate these products. As a difference with a typical extraction process the raffinate is in this separation problem the product to be recovered and for this reason the primary solvent properties are more restrictive than in conventional extraction processes.