溴氰菊酯低温热容的测定及热化学性质

采用精密自动绝热量热计测量了溴氰菊酯在80～400 K温区的热容，试样纯度为0.9926（摩尔分数）.在此温区内出现一个固-液熔化相变，其熔化温度T_m、摩尔熔化焓Δ_fusH_m、摩尔熔化熵Δ_fusS_m分别为（372.15±0.02）K，（26.73±0.02）kJ·mol^-1，（71.81±0.06）J·K^-1·mol^-1.报道了该物质在298.15～400 K温区内每隔5 K的热力学函数H_(T)-H_(298.15),S_(T)-S_(298.15),G_(T)-G_(298.15)值.采用DSC法对试样进行了测定，并与绝热量热法进行了比较.用热重法研究了该化合物的热分解行为，得到分解反应动力学参数反应级数n、频率因子A及活化能E分别为1.78，1.15×10⁹min^-1，603.8 kJ·mol^-1.

Determination of heat capacity of deltamethrin at low temperature and its thermochemical properties

The heat capacity of deltamethrin in the temperature range from 80 to 400 K was measured with a precise automatic adiabatic calorimeter.The sample was prepared with the purity of 0.9926 molar fraction. A solid-liquid fusion phase transition was observed in the experimental temperature range.The melting point, Tm, enthalpy and entropy of fusion, ΔfusHm,ΔfusSm, were determined as(372.15±0.02)K，(26.73±0.02)kJ·mol^-1，(71.81±0.06)J·K^-1·mol^-1 respectively.The thermodynamic functions data of deltamethrin,H_(T)-H_(298.15) ,S_(T) -S_(298.15) , and G_(T) -G_(298.15) , were reported with a temperature interval of 5 K in the temperature range of 298.15 to 400 K.The sample was measured with the DSC method and compared with the calorimetric method.The thermal decomposition of the sample was studied by TG analysis.The order of reaction n, pre-exponential factor A and activation energy E, were 1.78, 1.15×10⁹min^-1 and 603.8 kJ·mol^-1, respectively.