Thermochemistry and Gas-Phase Ion Energetics of 2-Hydroxy-4-methoxy-benzophenone (Oxybenzone)

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• 作者：A. F. Lago ; P. Jimenez ; R. Herrero ; J. Z. D&aacute ; valos ; J.-L. M. Abboud
• 刊名：Journal of Physical Chemistry A
• 出版年：2008
• 出版时间：April 10, 2008
• 年：2008
• 卷：112
• 期：14
• 页码：3201 - 3208
• 全文大小：248K
• 年卷期：v.112,no.14(April 10, 2008)
• ISSN：1520-5215

文摘

We have investigated the thermochemistry and ion energetics of the oxybenzone (2-hydroxy-4-methoxy-benzophenone, C₁₄H₁₂O₃, 1H) molecule. The following parameters have been determined for this species:gas-phase enthalpy for the of neutral molecule at 298.15K, (_fjournals/jpcafh/112/i14/eqn/jp7111999e10001.gif">(g) = -303.5 ± 5.1 kJ·mol^-1), the intrinsic(gas-phase) acidity (GA(1H) = 1402.1 ± 8.4 kJ·mol^-1), enthalpy of formation for the oxybenzone anion (_fjournals/jpcafh/112/i14/eqn/jp7111999e10002.gif">(1^-,g) = -402.3 ± 9.8 kJ·mol^-1). We also have obtained the enthalpy of formation of, 4-hydroxy-4'-methoxybenzophenone (_fjournals/jpcafh/112/i14/eqn/jp7111999e10003.gif">(g) = -275.4 ± 10 kJ·mol^-1) and 3-methoxyphenol anion (_fjournals/jpcafh/112/i14/eqn/jp7111999e10004.gif">(C₇H₇O₂^-,g)= -317.7 ± 8.7 kJ·mol^-1). A reliable experimental estimation of enthalpy related to intramolecular hydrogenbonding in oxybenzone has also been obtained (30.1 ± 6.3 kJ·mol^-1) and compared with our theoreticalcalculations at the B3LYP/6-311++G** level of theory, by means of an isodesmic reaction scheme. In addition,heat capacities, temperature, and enthalpy of fusion have been determined for this molecule by differentialscanning calorimetry.