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 ...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 en- tropy of fusion, △fusHm, △fusSm, 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, Sr-S298.15 and Gr-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 ×10^7 min^-1 , E =70.64 kJ/mol, respectively.展开更多
化工、纺织印染与农药化肥等产业的蓬勃发展推动着人类社会的进步,但同时也给环境治理带来了巨大难题。目前,光催化降解局限于在特定波长下针对单一有机污染物进行降解,然而现实中的情况往往更复杂。因此,开发一种多功能光催化材料用于...化工、纺织印染与农药化肥等产业的蓬勃发展推动着人类社会的进步,但同时也给环境治理带来了巨大难题。目前,光催化降解局限于在特定波长下针对单一有机污染物进行降解,然而现实中的情况往往更复杂。因此,开发一种多功能光催化材料用于光催化降解不同有机污染物显得尤为重要。采用一步无模板溶剂热法合成了核壳结构的C-TiO_(2)复合材料前驱体,并在氩气气氛下煅烧得到高结晶度的C-TiO_(2)复合光催化材料。运用SEM、TEM、XRD和TG等表征手段对材料进行表征,结论如下:550℃煅烧时的样品为包含少量碳的高结晶度的锐钛矿相TiO 2,且550℃煅烧时的样品依然保持了完整的核壳结构。此外,C-TiO_(2)复合材料的比表面积高达85.69 m 2·g^(-1),平均孔径为16.4 nm以及孔体积为0.423 m 3·g^(-1)。在UV-Vis光照射下,C-TiO_(2)复合材料分别对罗丹明B(RhB)、亚甲基蓝(MB)和刚果红(CR)3种染料显示出增强的光催化降解活性。展开更多
基金Supported by the Education Bureau Science Foundation of Liaoning Province,China(No.20040261).
文摘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 en- tropy of fusion, △fusHm, △fusSm, 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, Sr-S298.15 and Gr-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 ×10^7 min^-1 , E =70.64 kJ/mol, respectively.
文摘化工、纺织印染与农药化肥等产业的蓬勃发展推动着人类社会的进步,但同时也给环境治理带来了巨大难题。目前,光催化降解局限于在特定波长下针对单一有机污染物进行降解,然而现实中的情况往往更复杂。因此,开发一种多功能光催化材料用于光催化降解不同有机污染物显得尤为重要。采用一步无模板溶剂热法合成了核壳结构的C-TiO_(2)复合材料前驱体,并在氩气气氛下煅烧得到高结晶度的C-TiO_(2)复合光催化材料。运用SEM、TEM、XRD和TG等表征手段对材料进行表征,结论如下:550℃煅烧时的样品为包含少量碳的高结晶度的锐钛矿相TiO 2,且550℃煅烧时的样品依然保持了完整的核壳结构。此外,C-TiO_(2)复合材料的比表面积高达85.69 m 2·g^(-1),平均孔径为16.4 nm以及孔体积为0.423 m 3·g^(-1)。在UV-Vis光照射下,C-TiO_(2)复合材料分别对罗丹明B(RhB)、亚甲基蓝(MB)和刚果红(CR)3种染料显示出增强的光催化降解活性。