title: Theoretical study of unimolecular decomposition of catechol.
abstract: This study develops the reaction pathway map for the unimolecular decomposition of catechol, a model compound for various structural entities present in biomass, coal, and wood. Reaction rate constants at the high-pressure limit are calculated for the various possible initiation channels. It is found that catechol decomposition is initiated dominantly via hydroxyl H migration to a neighboring ortho carbon bearing an H atom. We identify the direct formation of o-benzoquinone to be unimportant at all temperatures, consistent with the absence of this species from experimental measurements. At temperatures higher than 1000 K, water elimination through concerted expulsion of a hydroxyl OH together with an ortho H becomes the most significant channel. Rice-Ramsperger-Kassel-Marcus simulations are performed to establish the branching ratio between these two important channels as a function of temperature and pressure. All unimolecular routes to the reported major experimental products (CO, 1,3-C(4)H(6) and cyclo-C(5)H(6)) are shown to incur large activation barriers. The results presented herein should be instrumental in gaining a better understanding of the decomposition behavior of catechol-related compounds.
authors.affiliation: Chemical Engineering Department, Al-Hussein Bin Talal University, Ma'an, Jordan.
authors.forename: Mohammednoor
authors.initials: M
authors.lastname: Altarawneh
authors.forename: Bogdan Z
authors.initials: BZ
authors.lastname: Dlugogorski
authors.forename: Eric M
authors.initials: EM
authors.lastname: Kennedy
authors.forename: John C
authors.initials: JC
authors.lastname: Mackie
mesh_terms: D000465:Algorithms; D016227:Benzoquinones / Q000737:chemistry; D002248:Carbon Monoxide / Q000737:chemistry; D002396:Catechols / Q000737:chemistry*; D006358:Hot Temperature; D007536:Isomerism; D007700:Kinetics; D008956:Models, Chemical; D008958:Models, Molecular; D008968:Molecular Conformation; D015394:Molecular Structure; D011312:Pressure; D013816:Thermodynamics; D014867:Water / Q000737:chemistry
chemical_list: D016227:Benzoquinones; D002396:Catechols; D014867:Water; D002248:Carbon Monoxide; C034221:catechol; C025225:2-benzoquinone