(163n) Adsorption of Dibenzothiophene and Its Alkyl Derivates in Polymers Containing Hydroxyl and Amino Groups

Dibenzothiophene (DBT) and its derivates are the main source of sulfur in oil [1]. Commonly used hydrodesulfurization (HDS) processes eliminate most of those compounds through decomposition reactions. Alkyl derivates of DBT have proven to be hard to eliminate with the traditional processes [2]. Adsorption of DBT and its derivates in polymers containing functionalized groups is proposed as an alternative/complementary process to HDS. In this work we studied the adsorption energies of DBT and its alkyl derivates in monomers of 2-methyl-,oxiranyl ester 2,4-Diamino-6-hydroxymethylpteridine (I) using Hartree-Fock (HF) and Density Functional Theory (DFT) calculations. Monomers of (I) can be synthesized through the ring-opening reaction of an epoxide (2-methyl-,oxiranyl ester) with a pteridine containing a hydroxyl group (2,4-diamino-6-hydroxymethylpteridine) [3]. The structures of the complexes were optimized using HF with the 3-21G(d) basis set while energies were calculated using DFT with the 6-31+G(d,p) basis set. The energies for the adsorption of DBT and its alkyl derivates as 4-Methyl-DBT and 4,6-Dimethyl-DBT in (I) will be presented and discussed in terms of the electron density of the complexes. Derivates of (I) that make more accessible the hydroxyl group to the sulfur atom of DBT and its derivates were also studied. Those derivates were built substituting the hydroxyl group in (I) for methyl-, ethyl-, n-propyl-, n-butyl, and n-pentyl alcohols. The adsorption energies of DBT and its alkyl derivates as a function of the number of carbons in the alcoholic chain will be presented and discussed in terms of the electron density of the complexes.

[1] D. Santamaria-Orozco, B. Horsfield, R. DiPrimo, D. H. Welte, Org. Geochem. 28, 423, 1998. [2] C. Song, Catal. Today, 8, 211, 2003. [3] D. Bradley, G. Williams, M. Lawton, Org. Biomol. Chem. 3. 3269, 2005.