Table 3 Kinetic analysis for the three active substances, the NPK method
From: Comparative kinetic analysis on thermal degradation of some cephalosporins using TG and DSC data
Process | λ (%) | E (kJ mol-1) | A (min-1) | n | m | Sestak-Bergrren Eq | ∑λ·E (kJ mol-1) | |
|---|---|---|---|---|---|---|---|---|
Cefadroxil | 1 | 95.4 | 258.6±7.1 | 1.33·1027 | 1 | - | (1-α) | 264.5±9.8 |
(DSC data) [20] | 2 | 4.6 | 385.4±83.8 | 1.07·1037 | - | 1/3 | α1/3 | |
Cephalexin | 1 | 77.2 | 220.2±9.7 | 8.04·1023 | 1 | - | (1-α) | 248.0±18.2 |
(DSC data) [11] | 2 | 18.9 | 412.4±162.2 | 3.40·1045 | 5/3 | 1 | α5/3 · (1-α) | |
Cefoperazone | 1 | 86.7 | 170.2±17.4 | 2.70·1018 | 2 | 1 | α · (1-α)2 | 179.9±14.9 |
(DSC data) | 2 | 13.3 | 243.8±17.6 | 7.18·1026 | 2 | 1 | α · (1-α)2 | |
Cefadroxil | 1 | 93.9 | 226.7±8.3 | 4.95·1023 | 2 | 1 | α · (1-α)2 | 231.9±14.1 |
(TG data) | 2 | 4.5 | 428.1±40.3 | 7.88·1044 | - | 0.1 | α0.1 | |
Cephalexin | 1 | 84.0 | 181.2±13.2 | 7.37·1019 | 1 | - | (1-α) | 220.6±13.2 |
(TG data) | 2 | 16.0 | 411.9±75.4 | 5.10·1045 | 0.1 | - | (1-α)0.1 | |
Cefoperazone | 1 | 71.4 | 141.5±6.0 | 9.16·1014 | 3 | - | (1-α)3 | 156.4±12.4 |
(TG data) | 2 | 22.5 | 245.6±83.6 | 5.80·1026 | - | 3 | α3 |