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The heat capacities of 3-(2,2-dichloroethenyl)-2,2-dimethylcyclopropanecarboxylic acid(a racemic mixture,molar ratio of cis-/trans-structure is 35/65)in a temperature range from 78 to 389 K were measured with a precise automatic adiabatic calorimeter.The sample was prepared with a purity of 98.75%(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,of the acid were determined to be(331.48±0.03)K,(16.321±0.031)kJ/mol,and(49.24±0.19)J/(K·mol),respectively.The thermodynamic functions of the sample,HT-H298.15,ST-S298.15 and GT-G298.15,were reported at a temperature intervals of 5 K.The thermal decomposition of the sample was studied using thermogravimetric(TG)analytic technique,the thermal decomposition starts at ca.418 K and ends at ca.544 K,the maximum decomposition rate was obtained at 510 K.The order of reaction,preexponential factor and activation energy are n=0.23,A=7.3×107 min-1,E=70.64 kJ/mol,respectively.
The heat capacities of 3- (2,2-dichloroethenyl) -2,2-dimethylcyclopropanecarboxylic acid (a racemic mixture, molar ratio of cis- / trans-structure is 35/65) in a temperature range from 78 to 389 K were measured A solid-liquid fusion phase transition was observed in the experimental temperature range. The melting point, Tm, enthalpy and entropy of fusion, ΔfusHm , ΔfusSm, of the acid were determined to be (331.48 ± 0.03) K, (16.321 ± 0.031) kJ / mol, and (49.24 ± 0.19) J / (K · mol) -H298.15, ST-S298.15 and GT-G298.15, were reported at a temperature intervals of 5 K. The thermal decomposition of the sample was studied using thermogravimetric (TG) analytic technique, the thermal decomposition starts at ca. 418 K and ends at ca. 544 K, the maximum decomposition rate was obtained at 510 K.The order of reaction, preexponential factor and activation energy are n = 0.23, A = 7.3 × 107 min-1, E = 70.64 kJ / mol, respectively.