物理化学学报
物理化學學報
물이화학학보
ACTA PHYSICO-CHIMICA SINICA
2010年
7期
1909-1914
,共6页
环己烷%单重态%偕离子对%辐解%磷酸三丁酯%水
環己烷%單重態%偕離子對%輻解%燐痠三丁酯%水
배기완%단중태%해리자대%복해%린산삼정지%수
Cyclohexane%Singlet%Geminate ions%Radiolysis%Tributylphosphate%Water
为确定辐解体系中烷烃单重态的来源,研究了水对环己烷(C6H12)-磷酸三丁酯(TBP)体系γ辐解和脉冲辐解的影响.水显著地抑制C6H12-TBP γ辐解体系中TBP酸式辐解产物的生成,酸式辐解产物的G值从无水体系的8.2降至水饱和体系的1.9,表明水分子既抑制了TBP自身辐解生成的TBP单重态,又通过阻断单重态C6H12与TBP之间的能量转移,消除了C6H12自身辐解对单重态TBP的酸式辐解产物的敏化作用.但在以二苯酮(Bp)为探针的TBP-Bp和C6H12-TBP-Bp脉冲辐解体系中,水的加入并未抑制辐解产物羰自由基的产额,其机理是,水分子通过与偕离子对反应而抑制C6H12单重态和TBP单重态的产生,但不影响羰自由基的生成.这也许是辐解体系中大部分(G=-1.3)单重态C6H12和部分(G=0.8)单重态TBP来源于偕离子对[C6H12·+…e-]和[TBP·+…e-]的复合的直接证据.由于极性较大,水可用作偕离子对的高效捕捉剂.
為確定輻解體繫中烷烴單重態的來源,研究瞭水對環己烷(C6H12)-燐痠三丁酯(TBP)體繫γ輻解和脈遲輻解的影響.水顯著地抑製C6H12-TBP γ輻解體繫中TBP痠式輻解產物的生成,痠式輻解產物的G值從無水體繫的8.2降至水飽和體繫的1.9,錶明水分子既抑製瞭TBP自身輻解生成的TBP單重態,又通過阻斷單重態C6H12與TBP之間的能量轉移,消除瞭C6H12自身輻解對單重態TBP的痠式輻解產物的敏化作用.但在以二苯酮(Bp)為探針的TBP-Bp和C6H12-TBP-Bp脈遲輻解體繫中,水的加入併未抑製輻解產物羰自由基的產額,其機理是,水分子通過與偕離子對反應而抑製C6H12單重態和TBP單重態的產生,但不影響羰自由基的生成.這也許是輻解體繫中大部分(G=-1.3)單重態C6H12和部分(G=0.8)單重態TBP來源于偕離子對[C6H12·+…e-]和[TBP·+…e-]的複閤的直接證據.由于極性較大,水可用作偕離子對的高效捕捉劑.
위학정복해체계중완경단중태적래원,연구료수대배기완(C6H12)-린산삼정지(TBP)체계γ복해화맥충복해적영향.수현저지억제C6H12-TBP γ복해체계중TBP산식복해산물적생성,산식복해산물적G치종무수체계적8.2강지수포화체계적1.9,표명수분자기억제료TBP자신복해생성적TBP단중태,우통과조단단중태C6H12여TBP지간적능량전이,소제료C6H12자신복해대단중태TBP적산식복해산물적민화작용.단재이이분동(Bp)위탐침적TBP-Bp화C6H12-TBP-Bp맥충복해체계중,수적가입병미억제복해산물탄자유기적산액,기궤리시,수분자통과여해리자대반응이억제C6H12단중태화TBP단중태적산생,단불영향탄자유기적생성.저야허시복해체계중대부분(G=-1.3)단중태C6H12화부분(G=0.8)단중태TBP래원우해리자대[C6H12·+…e-]화[TBP·+…e-]적복합적직접증거.유우겁성교대,수가용작해리자대적고효포착제.
To determine the origin of the radiolytic product singlet state of hydrocarbons,the effect of water on the γ-radiolysis and pulse radiolysis of cyclohexane(C6H12)-tributylphosphate (TBP)solution was studied.In the γ-radiolysis of C6H12-TBP solutions,the addition of water can remarkably lower the yield of the acid product of TBP.The G value of the acid product dropped from 8.2 in the system containing no water to about 1.9 in the system saturated with water.This suggests that water inhibits not only the output of singlet TBP directly induced by the radiation energy absorbed by TBP itself,but also the energy transfer from the singlet C6H12 to TBP.In the pulse radiolysis of TBP-benzophenone (Bp)solution and C6H12-TBP-Bp solutions with Bp as a probe,the added water did not depress the yield of the radiolytic intermediate ketyl radicals.This phenomenon can be interpreted as that water reacted with the geminate ions [C6H12(+)…e-]and[TBP(+)…e-],giving ketyl radicals but depressing the formation of singlet C6H12 and singlet TBP.This might be direct evidence that most(G=1.3)of the singlet C6H12 and part(G=0.8)of the singlet TBP come from the recombination of geminate ions[C6H12(+)…e-]and[TBP(+)…e-],respectively.Due to its high polarity,water could be used as a specific scavenger of the geminate ions that Can form excited states via fast geminate recombination.