Early maturation processes in coal. Part 2.pdfVIP

Organic Geochemistry 40 (2009) 1195–1209Contents lists available at ScienceDirect Organic Geochemistry journal homepage: www.elsevier .com/locate /orggeochemEarly maturation processes in coal. Part 2: Reactive dynamics simulations using the ReaxFF reactive force field on Morwell Brown coal structures Elodie Salmon a, Adri C.T. van Duin b, Fran?ois Lorant a, Paul-Marie Marquaire c, William A. Goddard III d,* a Institut Fran?ais du Pétrole, BP 311, 92506 Rueil-Malmaison Cedex, France bDepartment of Mechanical and Nuclear Engineering, Penn State University, University Park, PA 16802, USA cDépartement de Chimie Physique des Réactions (DCPR), Nancy-Université, CNRS 1 rue Grandville, BP 20451, F-54001 Nancy, France dMaterials and Process Simulation Center (MC 139-74), California Institute of Technology, Pasadena, CA 91125, USAa r t i c l e i n f o Article history: Received 20 April 2009 Received in revised form 31 August 2009 Accepted 2 September 2009 Available online 6 September6380/$ - see front matter  2009 Elsevier Ltd. A doi:10.1016/geochem.2009.09.001 * Corresponding author. Address: Materials and Pr 139-74), California Institute of Technology, 1200 East 91125, USA. Tel.: +1 626 395 2731; fax: +1 626 585 0 E-mail addresses: wag@, shirley@ dard).a b s t r a c t This paper reports reactive dynamics (RD) simulations of a macro-model of Morwell Brown coal using the ReaxFF reactive force field. We find that these reactive MD simulations successfully reproduce thermal decomposition processes of defunctionalization, depolymerization and rearrangement of the residual structure observed in various experimental studies. For example, our simulations indicate that the decar- boxylation and dehydroxylation of the lignin side chain of the Morwell model involves the formation of double bonds conjugated with the aromatic rings. The process of defunctionalization of the methoxy functions involving the formation of phenolic structures in the residue has been confirmed. We