title: Experimental and Theoretical Study of the High-Temperature UV-Visible Spectra of Aqueous Hydroquinone and 1,4-Benzoquinone.
abstract: UV-visible spectroscopic studies of aqueous hydroquinone (HQ) and 1,4-benzoquinone (BQ) have been carried out along with classical molecular dynamics (MD) and quantum calculations. The experimental results confirmed that HQ is stable in hot compressed water up to at least 523 K at 70 bar, but BQ decomposes at temperatures lower than 373 K, leading to the formation of HQ and other nonabsorbing products. Even though benzoquinone is not stable, our study significantly extended the temperature range of other spectroscopic studies, and the spectra of HQ up to 523 K can still be useful for other studies, particularly those related to organic species in deep ocean hydrothermal vents. Classical MD simulations at high temperatures show, as expected, a weakening of the solute-solvent H-bonding interactions. The dependence of the maximum absorption of BQ on temperature was also analyzed, although a significant degree of decomposition was observed in the time frame of our experiments. The shift of the maximum absorption peak of BQ with temperature was consistent with time-dependent density functional theory calculations.
authors.affiliation: Faculty of Science, University of Ontario Institute of Technology , 2000 Simcoe Street North, Oshawa L1H 7K4, Ontario, Canada.
authors.forename: Fereshteh
authors.initials: F
authors.lastname: Samiee
authors.affiliation: Departamento de Química Inorgánica, Analítica y Química Física, and INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria , Pab. 2, C1428EHA CABA, Argentina.
authors.forename: Federico N
authors.initials: FN
authors.lastname: Pedron
authors.affiliation: Departamento de Química Inorgánica, Analítica y Química Física, and INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria , Pab. 2, C1428EHA CABA, Argentina.
authors.forename: Dario A
authors.initials: DA
authors.lastname: Estrin
authors.affiliation: Faculty of Science, University of Ontario Institute of Technology , 2000 Simcoe Street North, Oshawa L1H 7K4, Ontario, Canada.
authors.forename: Liliana
authors.initials: L
authors.lastname: Trevani