Time- and Temperature-Varying Activation Energies: Isobutane Selective Oxidation to Methacrolein over Phosphomolybdic Acid and Copper(II) Phosphomolybdates
Abstract
:1. Introduction
2. Results
2.1. Temperature-Programmed, Low-Pressure, Pseudo Steady-State Methacrolein Formation
2.2. Rate Parameters from Temperature-Programmed, Low-Pressure Experiments
2.3. Calculating Time- and Temperature-Varying Activation Energies
3. Discussion
3.1. High-Temperature, Average Rate-Parameters for Methacrolein Formation
3.2. Detailed Rate-Parameter Distributions for Methacrolein Formation
3.3. Oscillations in High-Temperature Activation Energies
4. Materials and Methods
5. Conclusions
Acknowledgments
Author Contributions
Conflicts of Interest
References
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Catalyst | Temperature (°C) | (kJ·mol−1) |
---|---|---|
H3PMo12O40 | 246–451 | 99.3 ± 1.1 |
Cu0.5H2PMo12O40 | 353–502 | 61.3 ± 1.8 |
CuHPMo12O40 | 325–501 | 58.4 ± 0.9 |
Cu1.25H0.5PMo12O40 | 329–501 | 52 ± 4 |
Cu1.5PMo12O40 | 342–500 | 75.4 ± 1.2 |
Catalyst | Temperature (°C) | (s−1) | (kJ·mol−1) | |
---|---|---|---|---|
Min–Max | Average | |||
3rd Run | ||||
H3PMo12O40 | 300–433 | 8.7 ± 0.6 | 10–125 | 82 ± 27 |
CuHPMo12O40 | 310–435 | 8.3 ± 0.6 | 21–139 | 82 ± 31 |
Cu1.25H0.5PMo12O40 | 307–435 | 8.4 ± 0.6 | 24–128 | 83 ± 30 |
Cu1.5PMo12O40 | 311–438 | 7.8 ± 1.0 | 23–120 | 63 ± 30 |
4th Run | ||||
H3PMo12O40 | 359–479 | 8.9 ± 0.8 | 15–153 | 91 ± 35 |
Cu0.5H2PMo12O40 | 320–435 | 8.1 ± 0.7 | 20–134 | 72 ± 33 |
Cu1.25H0.5PMo12O40 | 308–433 | 8.3 ± 0.5 | 22–134 | 78 ± 32 |
Cu1.5PMo12O40 | 316–436 | 8.8 ± 1.4 | 22–139 | 76 ± 35 |
Catalyst | Temperature (°C) | (s−1) | (kJ·mol−1) | Reaction Type |
---|---|---|---|---|
3rd Run | ||||
H3PMo12O40 | 345–384 | 10 9.1 ± 0.1 | 99 ± 9 | III |
387–412 | 10 8.7 ± 0.2 | 80 ± 8 | II | |
414–433 | 10 9.3 ± 0.2 | 111 ± 9 | IV | |
CuHPMo12O40 | 351–406 | 10 8.34 ± 0.07 | 85 ± 4 | III |
413–435 | 10 9.04 ± 0.04 | 131 ± 6 | I | |
Cu1.25H0.5PMo12O40 | 353–399 | 10 8.6 ± 0.1 | 90 ± 5 | III |
413–435 | 10 9.2 ± 0.03 | 126 ± 2 | I | |
Cu1.5PMo12O40 | 331–369 | 10 7.1 ± 0.2 | 44 ± 5 | V |
379–393 | 10 9.5 ± 0.1 | 115 ± 4 | IV | |
414–427 | 10 6.7 ± 0.1 | 19 ± 3 | V | |
429–438 | 10 8.3 ± 0.3 | 73 ± 12 | II | |
4th Run | ||||
H3PMo12O40 | 381–408 | 10 9.0 ± 0.1 | 98 ± 5 | III |
413–435 | 10 8.6 ± 0.1 | 76 ± 6 | II | |
450–479 | 10 9.8 ± 0.2 | 131 ± 10 | I | |
Cu0.5H2PMo12O40 | 351–402 | 10 8.1 ± 0.1 | 72 ± 5 | II |
416–435 | 10 9.2 ± 0.1 | 125 ± 5 | I | |
Cu1.25H0.5PMo12O40 | 352–400 | 10 8.3 ± 0.1 | 79 ± 6 | II |
414–433 | 10 9.04 ± 0.04 | 130 ± 3 | I | |
Cu1.5PMo12O40 | 357–403 | 10 8.8 ± 0.2 | 74 ± 4 | II |
417–436 | 10 11.1 ± 0.1 | 134 ± 3 | I |
Catalyst | Temperature (°C) | (kJ·mol−1) | (K) | (kJ·mol−1·K−1) | (kJ·mol−1) |
---|---|---|---|---|---|
3rd Run | |||||
H3PMo12O40 | 307–368 | 18 | 44 | 0.40 | −58 |
370–435 | 19 | 46 | 0.23 | 0.074 | |
CuHPMo12O40 | 310–366 | 1.2 | 44 | 1.2 | −334 |
368–425 | 13 | 43 | 1.1 | −320 | |
Cu1.25H0.5PMo12O40 | 307–368 | 15 | 44 | 1.1 | −298 |
370–435 | 5.0 | 45 | 0.88 | −249 | |
Cu1.5PMo12O40 | 313–369 | 12 | 44 | −0.45 | 202 |
372–438 | 33 | 43 | −1.5 | 669 | |
4th Run | |||||
H3PMo12O40 | 359–421 | 28 | 47 | 1.1 | −340 |
423–479 | 9.0 | 44 | 1.3 | −484 | |
Cu0.5H2PMo12O40 | 319–373 | 14 | 43 | 1.2 | −358 |
375–435 | 12 | 41 | 1.3 | −454 | |
Cu1.25H0.5PMo12O40 | 308–371 | 14 | 44 | 0.93 | −263 |
374–433 | 9.6 | 45 | 1.3 | −415 | |
Cu1.5PMo12O40 | 316–369 | 20 | 44 | 0.40 | −93 |
372–436 | 13 | 46 | 1.3 | −430 |
Catalyst | Reaction | ||||
---|---|---|---|---|---|
(kJ·mol−1·K −1) | (kJ·mol−1) | (kJ·mol−1) | (K) | ||
H3PMo12O40 | Type I | 1.3 | −484 | 130 ± 3 | 745 ± 7 |
Type II | 1.3 | −484 | 76 ± 3 | 704 ± 7 | |
Type III | 1.1 | −340 | 93 ± 7 | 667 ± 25 | |
Cu0.5H2PMo12O40 | Type I Type II | 1.3 1.3 | −433 −433 | 130 ± 3 76 ± 3 | 706 ± 9 665 ± 9 |
Cu1.25H0.5PMo12O40 | |||||
Cu1.5PMo12O40 |
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Brown, T.C.; Miron, D.J.; Brown, S.L.; Kendell, S.M. Time- and Temperature-Varying Activation Energies: Isobutane Selective Oxidation to Methacrolein over Phosphomolybdic Acid and Copper(II) Phosphomolybdates. Catalysts 2016, 6, 137. https://doi.org/10.3390/catal6090137
Brown TC, Miron DJ, Brown SL, Kendell SM. Time- and Temperature-Varying Activation Energies: Isobutane Selective Oxidation to Methacrolein over Phosphomolybdic Acid and Copper(II) Phosphomolybdates. Catalysts. 2016; 6(9):137. https://doi.org/10.3390/catal6090137
Chicago/Turabian StyleBrown, Trevor C., David J. Miron, Susannah L. Brown, and Shane M. Kendell. 2016. "Time- and Temperature-Varying Activation Energies: Isobutane Selective Oxidation to Methacrolein over Phosphomolybdic Acid and Copper(II) Phosphomolybdates" Catalysts 6, no. 9: 137. https://doi.org/10.3390/catal6090137