Reexamination of the Pyrolysis of Polyethylene: Data Needs, Free-Radical Mechanistic Considerations, and Thermochemical Kinetic Simulation of Initial Product-Forming Pathways

Macromolecules

Volumn 36, Issue 24, 2003, Pages 8931-8957

  Poutsma, Marvin L ^a  

^a OAK RIDGE NATIONAL LABORATORY   (United States)

Author keywords

[No Author keywords available]

Indexed keywords

COMPUTER SIMULATION; FREE RADICAL REACTIONS; ISOTHERMS; PYROLYSIS; REACTION KINETICS; STATISTICAL TESTS; THERMOGRAVIMETRIC ANALYSIS; THERMOMECHANICAL TREATMENT; VAPORIZATION;

HOMOLYSIS EFFECTS; MOLECULAR DISPROPORTIONATION;

POLYETHYLENES;

EID: 0345117058     PISSN: 00249297     EISSN: None     Source Type: Journal    
DOI: 10.1021/ma0303768     Document Type: Review

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166. i" term (ref 40a).
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170. -1.
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324. If the PnR involved in forming PENEn happened to be a near-end PmR (formed either by direct transfer from P, 1,x-shift within PnR, or further transfer between PnR and P), there would be an added contribution from the resulting ΣENEr and ΣPENEm that is not included in this definition. However, for large MW and hence m ≪ n, this correction is trivial and any ENEs so formed would be statistically distributed without any of the specificity characteristic of BB.
325. β(s,Me).
326. 1,x-Shifts and β-scissions in both directions are included in this generic ratio, although some of these processes may not be structurally allowed for small m.
327. The chosen lower limit of c = 3 purposely excludes the ENE2Z formed from UZ, and the chosen upper limit of c = 20 minimizes perturbations caused by the truncation of the PmR series at m = 30.
328. -1) at 500 °, and hence the differences will be slightly larger/smaller at lower/higher T.
329. 1x values were characterized by a major increase in the amount of truncation as the population of PmR with m > 30 became for the first time nontrivial.
330. 16 set to zero of course gave even sharper maxima. However, minor amounts of volatiles were still formed at other than the "magic" c values; these are derived from successive formation of Ar1R, Ar6R, ... and β-scission of the latter.
331. Because of the truncation at c = 25, the actual "wt % RS" will be somewhat larger because the RS contribution extends further toward higher c values than does the BB contribution. For the most conservative assumption that no BB products occur for c > 25 (the simulation begins to become statistically unreliable at this point because of the truncation at m = 30), the actual wt % RS values over the c range to 1-100 (the RS contribution becomes vanishingly small for c > 100) would be 32.6, 64.3, and 77.1 wt % rather than 25, 50, and 75 wt %.
332. Ranzi, E.; Faravelli, T.; Gaffuri, P.; Sogaro, A. Combust. Flame 1995, 102, 179. Ranzi, E.; Dente, M.; Pierucci, S.; Biardi, G. Ind. Eng. Chem. Fundam. 1983, 22, 132.
333. Ranzi, E.; Faravelli, T.; Gaffuri, P.; Sogaro, A. Combust. Flame 1995, 102, 179. Ranzi, E.; Dente, M.; Pierucci, S.; Biardi, G. Ind. Eng. Chem. Fundam. 1983, 22, 132.
334. Numerous other sources for rate constant assignments are available (ref 215), including several used to model the pyrolysis of hexadecane (refs 162d, 202, and 216), but none provide a complete set.
335. Allara, D. L.; Shaw, R. J. Phys. Chem. Ref. Data 1980, 9, 523. Nigam, A. ; Klein, M. T. Ind. Eng. Chem. Res. 1998, 32, 1297. De Witt, M. J.; Dooling, D. J.; Broadbelt, L. J. Ind. Eng. Chem. Res. 2000, 39, 2228. Bounaceur, R.; Warth, V.; Marquaire, P.-M.; Scacdii, G.; Domine, F.; Dessort, D.; Pradier, B.; Brevart, O. J. Anal. Appl. Pyrolysis 2002, 64, 103.
336. Allara, D. L.; Shaw, R. J. Phys. Chem. Ref. Data 1980, 9, 523. Nigam, A. ; Klein, M. T. Ind. Eng. Chem. Res. 1998, 32, 1297. De Witt, M. J.; Dooling, D. J.; Broadbelt, L. J. Ind. Eng. Chem. Res. 2000, 39, 2228. Bounaceur, R.; Warth, V.; Marquaire, P.-M.; Scacdii, G.; Domine, F.; Dessort, D.; Pradier, B.; Brevart, O. J. Anal. Appl. Pyrolysis 2002, 64, 103.
337. Allara, D. L.; Shaw, R. J. Phys. Chem. Ref. Data 1980, 9, 523. Nigam, A. ; Klein, M. T. Ind. Eng. Chem. Res. 1998, 32, 1297. De Witt, M. J.; Dooling, D. J.; Broadbelt, L. J. Ind. Eng. Chem. Res. 2000, 39, 2228. Bounaceur, R.; Warth, V.; Marquaire, P.-M.; Scacdii, G.; Domine, F.; Dessort, D.; Pradier, B.; Brevart, O. J. Anal. Appl. Pyrolysis 2002, 64, 103.
338. Allara, D. L.; Shaw, R. J. Phys. Chem. Ref. Data 1980, 9, 523. Nigam, A. ; Klein, M. T. Ind. Eng. Chem. Res. 1998, 32, 1297. De Witt, M. J.; Dooling, D. J.; Broadbelt, L. J. Ind. Eng. Chem. Res. 2000, 39, 2228. Bounaceur, R.; Warth, V.; Marquaire, P.-M.; Scacdii, G.; Domine, F.; Dessort, D.; Pradier, B.; Brevart, O. J. Anal. Appl. Pyrolysis 2002, 64, 103.
339. Doue, F.; Guiochon, G. J. Chim. Phys. Physiochim. Biol. 1968, 65, 395. Doue, F.; Guiochon, G. Can. J. Chem. 1969, 47, 3477, Depeyre, D.; Flicoteaux, C. Ind. Eng. Chem. Res. 1991, 30, 1116, Khorasheh, F.; Gray, M. R. Ind. Eng. Chem. Res. 1998, 32, 1853. Ristori, A.; Dagaut, P.; Cathonnet, M. Combust. Flame 2001, 125, 1128. Watanabe, M.; Adschiri, T.; Arai, K. Ind. Eng. Chem. Res. 2001, 40, 2027.
340. Doue, F.; Guiochon, G. J. Chim. Phys. Physiochim. Biol. 1968, 65, 395. Doue, F.; Guiochon, G. Can. J. Chem. 1969, 47, 3477, Depeyre, D.; Flicoteaux, C. Ind. Eng. Chem. Res. 1991, 30, 1116, Khorasheh, F.; Gray, M. R. Ind. Eng. Chem. Res. 1998, 32, 1853. Ristori, A.; Dagaut, P.; Cathonnet, M. Combust. Flame 2001, 125, 1128. Watanabe, M.; Adschiri, T.; Arai, K. Ind. Eng. Chem. Res. 2001, 40, 2027.
341. Doue, F.; Guiochon, G. J. Chim. Phys. Physiochim. Biol. 1968, 65, 395. Doue, F.; Guiochon, G. Can. J. Chem. 1969, 47, 3477, Depeyre, D.; Flicoteaux, C. Ind. Eng. Chem. Res. 1991, 30, 1116, Khorasheh, F.; Gray, M. R. Ind. Eng. Chem. Res. 1998, 32, 1853. Ristori, A.; Dagaut, P.; Cathonnet, M. Combust. Flame 2001, 125, 1128. Watanabe, M.; Adschiri, T.; Arai, K. Ind. Eng. Chem. Res. 2001, 40, 2027.
342. Doue, F.; Guiochon, G. J. Chim. Phys. Physiochim. Biol. 1968, 65, 395. Doue, F.; Guiochon, G. Can. J. Chem. 1969, 47, 3477, Depeyre, D.; Flicoteaux, C. Ind. Eng. Chem. Res. 1991, 30, 1116, Khorasheh, F.; Gray, M. R. Ind. Eng. Chem. Res. 1998, 32, 1853. Ristori, A.; Dagaut, P.; Cathonnet, M. Combust. Flame 2001, 125, 1128. Watanabe, M.; Adschiri, T.; Arai, K. Ind. Eng. Chem. Res. 2001, 40, 2027.
343. Doue, F.; Guiochon, G. J. Chim. Phys. Physiochim. Biol. 1968, 65, 395. Doue, F.; Guiochon, G. Can. J. Chem. 1969, 47, 3477, Depeyre, D.; Flicoteaux, C. Ind. Eng. Chem. Res. 1991, 30, 1116, Khorasheh, F.; Gray, M. R. Ind. Eng. Chem. Res. 1998, 32, 1853. Ristori, A.; Dagaut, P.; Cathonnet, M. Combust. Flame 2001, 125, 1128. Watanabe, M.; Adschiri, T.; Arai, K. Ind. Eng. Chem. Res. 2001, 40, 2027.
344. Doue, F.; Guiochon, G. J. Chim. Phys. Physiochim. Biol. 1968, 65, 395. Doue, F.; Guiochon, G. Can. J. Chem. 1969, 47, 3477, Depeyre, D.; Flicoteaux, C. Ind. Eng. Chem. Res. 1991, 30, 1116, Khorasheh, F.; Gray, M. R. Ind. Eng. Chem. Res. 1998, 32, 1853. Ristori, A.; Dagaut, P.; Cathonnet, M. Combust. Flame 2001, 125, 1128. Watanabe, M.; Adschiri, T.; Arai, K. Ind. Eng. Chem. Res. 2001, 40, 2027.
345. For a detailed illustration of this approach applied to polyisobutylene, see: Lehrle, R. S.; Pattenden, C. S. Polym. Degrad. Stab. 1999, 63, 321.
346. exp = 0.082, and v = 0.110 for Phillips HDPE are not likely statistically different, given our derivation of the values from reading graphical data from the original publication.
347. 1x ratios. For example, repeating the exercise in Table 7 for case 3 in Table 6, that with the highest selectivity for 1,5-shift, would give the best match at of course a higher proportion of unselective RS, specifically 84 wt % RS with s ≈ 0.072.
348. As a possible example of the latter phenomenon for polypropylene, see ref 78.