One new hydrated barium hexaborate has been prepared and identified by chemical analysis,X-ray diffraction(XRD),infrared spectral(IR) and thermal analysis(TG-DTG,DSC).The constitute of sample is BaB6O10·4.5H2O.Th...One new hydrated barium hexaborate has been prepared and identified by chemical analysis,X-ray diffraction(XRD),infrared spectral(IR) and thermal analysis(TG-DTG,DSC).The constitute of sample is BaB6O10·4.5H2O.The structure and thermal decomposition process of sample were studied.The molar enthalpies of solution of BaB6O10·4.5H2O in 1 mol·dm-3 HCl(aq)were measured in a series of experiments.With the incorporation of the previously determined enthalpy of solution of other substances in HCl(aq) and the standard molar enthalpies of formation of related substances,the standard molar enthalpies of formation of BaB6O10·4.5H2O was obtained.展开更多
采用CCSD(T)//B3LYP/6-311+G(d,p)方法研究了Criegee中间体CH_3CHOO与OH自由基反应的微观机理.结果表明,上述反应存在抽氢、加成-分解和氧化3类反应通道,其中,syn-CH3CHOO+OH以抽β-H为优势通道,表观活化能为-4.88 k J/mol;anti-CH_3CHO...采用CCSD(T)//B3LYP/6-311+G(d,p)方法研究了Criegee中间体CH_3CHOO与OH自由基反应的微观机理.结果表明,上述反应存在抽氢、加成-分解和氧化3类反应通道,其中,syn-CH3CHOO+OH以抽β-H为优势通道,表观活化能为-4.88 k J/mol;anti-CH_3CHOO+OH则以加成-分解反应为优势通道,表观活化能为-13.25 k J/mol.在加成-分解和氧化反应通道中,anti-构象的能垒均低于syn-构象,而抽氢反应则是syn-(β-H)的能垒低于anti-构象.速率常数计算表明,anti-构象的加成-分解反应通道具有显著的负温度效应;syn-和anti-构象的氧化通道具有显著的正温度效应.3类反应具有显著不同的温度效应,说明通过改变温度可显著调节3类反应的相对速率.展开更多
文摘One new hydrated barium hexaborate has been prepared and identified by chemical analysis,X-ray diffraction(XRD),infrared spectral(IR) and thermal analysis(TG-DTG,DSC).The constitute of sample is BaB6O10·4.5H2O.The structure and thermal decomposition process of sample were studied.The molar enthalpies of solution of BaB6O10·4.5H2O in 1 mol·dm-3 HCl(aq)were measured in a series of experiments.With the incorporation of the previously determined enthalpy of solution of other substances in HCl(aq) and the standard molar enthalpies of formation of related substances,the standard molar enthalpies of formation of BaB6O10·4.5H2O was obtained.
文摘采用CCSD(T)//B3LYP/6-311+G(d,p)方法研究了Criegee中间体CH_3CHOO与OH自由基反应的微观机理.结果表明,上述反应存在抽氢、加成-分解和氧化3类反应通道,其中,syn-CH3CHOO+OH以抽β-H为优势通道,表观活化能为-4.88 k J/mol;anti-CH_3CHOO+OH则以加成-分解反应为优势通道,表观活化能为-13.25 k J/mol.在加成-分解和氧化反应通道中,anti-构象的能垒均低于syn-构象,而抽氢反应则是syn-(β-H)的能垒低于anti-构象.速率常数计算表明,anti-构象的加成-分解反应通道具有显著的负温度效应;syn-和anti-构象的氧化通道具有显著的正温度效应.3类反应具有显著不同的温度效应,说明通过改变温度可显著调节3类反应的相对速率.
