Abstract
運用雷射光解—雷射誘發螢光法於171至401托爾(torr)的壓力及333至386 K的溫度範圍內，我們研究了羥基與苯的平衡反應。 經由分析羥基濃度的時間輪廓圖，可獲得各相關反應詳盡的反應速率係數，以及反應OH+C6H6+M=HOC6H6+M的平衡常數。 其正向反應速率係數kf=(8.4±0.7)E-13 cc/molecule s，逆向反應速率係數kr= (3.4±0.6)E12×exp[-(8100±800)/T] / s，而反應中間體HOC6H6衰減速率係數為ka=(1.85±0.03)E10×exp[-(6900±900)/T]/s，並由平衡常數推導出反應熱△H=-(19.7±1.0) kcal / mol，以及焓的變化△S=-(33.4±1.3)cal / K mol，均較以往的報告為大。The reaction between OH and C6H6 in He has been studied overthe pressure range 171-401 torr and the temperature range333-386 K by means of the laser-photolysis/laser- inducedfluorescence technique. Analysis of the temporal profile of[OH] yielded the detailed rate coefficients and the equilibriumconstant for the reaction OH+C6H6+M=HOC6H6 +M. Thetemperature dependence of the rate coefficients for theforward, the reverse and the adduct-loss reactions have beendetermined to be: kf=(8.4±0.7)E-13 cc/molecule s, kr=(3.4±0.6)E12×exp[-(8100±800)/T] / s, ka=(1.85± 0.03)E10×exp[-(6900±900)/T] / s. The temperature dependence of the equilibriumconstant led to the enthalpy of reaction △H = -(19.7±1.0)kcal / mol and the entropy of reaction △S = -(33.4±1.3) cal /K mol, greater than previously reported values.