1. Associate Researcher, Dept. of Chemistry, UFOP, Campus Morro do Cruzeiro Ouro Preto, MG–35.400.000, Brazil (corresponding author). E-mail: sergio@iceb.ufop.br
2. Professor, Dept. of Chemical Engineering, Imperial College London, Prince Consort Rd., London SW7 2BY, U.K. E-mail: d.stuckey@imperial.ac.uk