Phase equilibria and solvent selection for a multiphase reaction-extraction system to produce 4-methyl-1,3-dioxane

Fluid Phase Equilibria, vol. 610, pp. 114789

Abstract

This study investigates phase-equilibrium data relevant to a multiphase reaction-extraction system for the synthesis of 4-methyl-1,3-dioxane (4-MDX) from H 2 , CO 2 , and 1,3-butanediol (1,3-BDO). The polar 1,3-BDO reaction phase is contacted with a nonpolar solvent to extract 4-MDX in situ into a second liquid phase. Based on experimental liquid-liquid equilibrium (LLE) data, a suitable solvent is selected and examined to provide a thermodynamic basis for extraction-process design. Therefore, binary LLE data for 1,3-BDO with five nonpolar solvents ( n- decane, iso- octane, n- heptane, cyclohexane, toluene) from 293 to 353 K, ternary LLE data for 1,3-BDO/4-MDX/ n -decane and 1,3-BDO/water/ n -decane from 293 to 353 K, quaternary LLE data for 1,3-BDO/4-MDX/water/ n -decane at 353 K, and binary vapor-liquid equilibrium (VLE) data for 4-MDX/ n -decane at 992.64 hPa were measured. Since all solvents exhibited 4-MDX partition coefficients of the same order of magnitude, n -decane was selected because it showed the highest extraction selectivity for 4-MDX over 1,3-BDO (160.85) and the lowest mutual solubility with 1,3-BDO. In the 1,3-BDO/ n -decane system, the 4-MDX partition coefficient ranged from 1.11 to 1.26 and was not significantly affected by temperature or 4-MDX feed concentration. In the quaternary system, the extraction selectivity for 4-MDX over 1,3-BDO increased with increasing water content and decreasing 4-MDX content. Experimentally determined binary VLE data for the 4-MDX/ n -decane system revealed high relative volatilities, indicating feasible separation by distillation. The LLE data were modeled by regressing parameters of the Perturbed-Chain Statistical Associating fluid theory (PC-SAFT) equation of state, whereas the VLE data were correlated by regressing parameters of the non-random two-liquid (NRTL) model.

Authors 2

1. Moritz Haas Aachen Fluid Process Engineering (AVT.FVT)

   RWTH Aachen University

   Affiliation as printed

   Fluid Process Engineering (AVT.FVT), RWTH Aachen University, 52074 Aachen, Germany

2. Andreas Jupke corresponding Aachen Fluid Process Engineering (AVT.FVT)

   RWTH Aachen University · Forschungszentrum Jülich

   Affiliation as printed

   Fluid Process Engineering (AVT.FVT), RWTH Aachen University, 52074 Aachen, Germany

   Institute for Bio- and Geosciences (IBG-2), Forschungszentrum Jülich GmbH, 52428 Jülich, Germany