Table 1 Activation energy’s values obtained by Friedman isoconversional method for the three analyzed cephalosporins from DSC data (a) respectively TG data (b)
From: Comparative kinetic analysis on thermal degradation of some cephalosporins using TG and DSC data
E a kJ mol-1 | Conversion degree α |
kJ mol-1 | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 | ||
Cefadroxil (a)[20] | 510.3 | 475.9 | 468.3 | 399.5 | 355.7 | 331.1 | 259.1 | 245.8 | 194.9 | 360.1 |
±1.0 | ±0.5 | ±1.4 | ±2.8 | ±12.8 | ±3.6 | ±7.5 | ±9.9 | ±10.8 | ±37.4 | |
Cephalexin (a) [11 | 257.7 | 249.9 | 256.8 | 251.8 | 255.8 | 243.5 | 266.2 | 284.5 | 295.1 | 262.4 |
±2.3 | ±4.0 | ±5.9 | ±2.5 | ±3.8 | ±7.0 | ±12.5 | ±5.7 | ±9.8 | ±5.6 | |
Cefoperazone (a) | 147.0 | 164.4 | 189.6 | 202.8 | 196.5 | 186.1 | 192.6 | 204.3 | 269.8 | 194.8 |
±3.3 | ±2.8 | ±4.1 | ±1.7 | ±2.9 | ±6.2 | ±4.0 | ±9.1 | ±8.7 | ±11.2 | |
Cefadroxil (b) | 373.6 | 432.6 | 403.3 | 381.5 | 306.8 | 300.9 | 211.3 | 159.2 | 118.4 | 298.6 |
±5.2 | ±3.9 | ±2.0 | ±1.3 | ±1.5 | ±13.2 | ±6.9 | ±13.2 | ±2.7 | ±37.5 | |
Cephalexin (b) | 272.9 | 257.2 | 247.1 | 253.5 | 246 | 232.5 | 224.7 | 231.9 | 209.7 | 241.7 |
±3.2 | ±7.4 | ±2.4 | ±13.6 | ±11.2 | ±33.6 | ±8.4 | ±9.6 | ±8.8 | ±6.3 | |
Cefoperazone (b) | 168.8 | 195.5 | 192.1 | 165.3 | 68.1 | 39.9 | 61.1 | 131.0 | 271.7 | 143.7 |
±3.8 | ±4.1 | ±6.4 | ±3.9 | ±2.2 | ±8.6 | ±8.6 | ±3.3 | ±15.0 | ±25.3 | |