Tuesday, November 6, 2007 - 4:54 PM

A New Material for the Selective Olefin/paraffin Separation by Adsorption

Lourdes F. Vega1, Carmelo Herdes2, Anabela Valente3, Zhi Lin3, Joao Rocha3, and Joao A.P. Coutinho3. (1) MatGas Research Center. Air Products-CSIC-UAB, Campus de la UAB., Bellaterra. Barcelona, 08193, Spain, (2) Institut de Cičncia de Materials de Barcelona, Consejo Superior de Investigaciones Científicas, ICMAB-CSIC. Campus de la UAB, Bellaterra. Barcelona, 08193, Spain, (3) Department of Chemistry, CICECO, Universidade de Aveiro, Aveiro, 3810-193, Portugal

The aim of the present work is twofold: (1) to propose an adsorbent material selective to ethyl chloride versus vinyl chloride and (2) to find a robust model, based on Monte Carlo simulations, for predictive purposes concerning the separation of ethyl chloride/vinyl chloride at optimal conditions. We present here results concerning the adsorption capacity of aluminum methyl phosphonate polymorph alpha (AlMePO-alpha) for pure ethyl chloride and vinyl chloride by measured/calculated individual adsorption isotherms of these pure compounds. Simulations were performed by the Grand Canonical Monte Carlo technique using our recently proposed molecular simulation framework for gas adsorption on AlMePO-alpha; We have improved an existing model for ethyl chloride in order to better capture the experimental dipole value; and equivalent molecular model for the vinyl chloride molecule was also developed for the simulation purposes. The molecular model of the material was used in a pure transferable manner from our previous work2. Simulations of the pure compounds were found to be in excellent agreement with the measured experimental data. Once the model was proved to be reliable, simulations were them used in a purely predictive manner as a tool to find the optimal conditions for the selective adsorption of these compounds. Results support the use of the AlMePO-alpha; as an appropriate adsorbent in the purification process of vinyl chloride, upholding the selective adsorption of the paraffin.