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Volumn 68, Issue 11, 2003, Pages 4247-4257

The surprisingly facile thermal dehalogenation of chlorinated aromatics by a hydroaromatic donor solvent. Tautomerization of chlorinated phenols and anilines

Author keywords

[No Author keywords available]

Indexed keywords

REVERSE RADICAL DISPROPORTIONATION (RRD);

EID: 0038779451     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo0265885     Document Type: Article
Times cited : (12)

References (50)
  • 5
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    • Ph.D. Thesis, Leiden University
    • (b) Brink, R. W. Ph.D. Thesis, Leiden University, 1999.
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    • Ph.D. Thesis, Leiden University
    • (b) Arends, I. W. C. E. Ph.D. Thesis, Leiden University, 1993.
    • (1993)
    • Arends, I.W.C.E.1
  • 14
    • 0001426491 scopus 로고    scopus 로고
    • (b) However, the decarboxylation might also occur by an electrophilic pathway via protonation of the aromatic ring by another molecule of benzoic acid: Eskay. T. P.; Britt, P. F.; Buchanan, A. C., III Energy Fuels 1997, 11, 1278-1287.
    • (1997) Energy Fuels , vol.11 , pp. 1278-1287
    • Eskay, T.P.1    Britt, P.F.2    Buchanan A.C. III3
  • 15
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    • note
    • (a) The most volatile of the investigated substrates is 4 (bp 448 K). Its vapor pressure at the applied temperature (630 K) is 4.9 atm (ref 10b). Charging the reaction tube with 0.6 mmol of 4, 2.2 mmol of 1 (bp 585 K), and 0.15 mmol of dibenzofuran (bp 560 K) (internal standard), leaves a headspace volume of 1.9 mL. Applying Raoult's law, approximately 30% of 4 would stay in the gas phase (decreasing to 14% with 6, bp 493 K). By addition of typically 0.6 mmol of water (only in the case of phenyl derivatives) - corresponding to approximately 19 atm of overpressure under ideal gas approximation - virtually the entire substrate remains in the liquid phase. The substrate/water ratio was at least 1. Water was chosen because of the obvious advantage of not adding additional organic material to the reaction mixture.
  • 19
    • 84986694135 scopus 로고
    • A comparable observation has been reported for the self-decomposition of 2-chloro-4-methoxy-1-naphthol. At room temperature and in the presence of an acid, this compound dimerizes within a few hours with loss of chloride and methoxyl into a mono-chloronaphthofuran derivative. Isomers with the Cl at the C-3 position are stable: Laatsch, H. Liebigs Ann. Chem. 1991, 385-386.
    • (1991) Liebigs Ann. Chem. , pp. 385-386
    • Laatsch, H.1
  • 20
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    • note
    • fH(39) = 58.96.
  • 21
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    • Neutral thermochemical data
    • Linstrom P. J., Mallard, W. G., Eds; July 2001; National Institute of Standards and Technology, Gaithersburg MD
    • (b) Afeefy, H. Y.; Liebman, J. F.; Stein, S. E. Neutral Thermochemical Data. In NIST Chemistry WebBook, NIST Standard Reference Database Number 69; Linstrom P. J., Mallard, W. G., Eds; July 2001; National Institute of Standards and Technology, Gaithersburg MD, 2001 (http://webbook.nist.gov).
    • (2001) NIST Chemistry WebBook, NIST Standard Reference Database Number 69
    • Afeefy, H.Y.1    Liebman, J.F.2    Stein, S.E.3
  • 29
    • 0038432921 scopus 로고    scopus 로고
    • note
    • rH of 2.40 (3a), -0.34 (3b), 0.70 (33a), -0.20 (33b), 0.64 (31b), 2.60 (10a), 0.40 (10b), 2.60 (35a), 0.90 (35b), and 2.10 (39b).
  • 30
    • 0038432922 scopus 로고    scopus 로고
    • note
    • -1, respectively (data from ref 6, except for 1,3-cyclohexadiene, 1,4-cyclohexadiene). Thus DFT, for example, underestimates the BDE(C-H) in 1,4-cyclohexadiene and overestimates the HA for benzene suggesting an erroneous computational handling of the radical and the diene.
  • 32
    • 0037756431 scopus 로고    scopus 로고
    • note
    • -1 below the best experimental value (ref 21e). As for the phenols, it may be assumed that the ABDE(N-H) values for the aromatic amines are sufficiently reliable (ref 21f). The change in BDE (O-H) or BDE(N-H) in phenyl derivatives upon ring substitution can be mainly attributed to the degree of delocalization of the unpaired electron in the corresponding phenoxyl and anilinyl radicals (refs 20c and 20f). This also appears to be valid when expanding the aromatic system from phenyl to anthracenyl. The effect is more profound for O-H than for N-H bonds, because of the higher intrinsic spin delocalization in aromatic oxyl than in aminyl radicals.
  • 41
    • 0038094125 scopus 로고    scopus 로고
    • note
    • -1 the benzylic BDE(C-H) for 1, as computed by DFT (ref 20).
  • 42
    • 0038432923 scopus 로고    scopus 로고
    • note
    • 2CNH, and benzyl alcohol (after hydrogen abstraction from the solvent). Computations have revealed that the N-O bond in the adduct radical is weak, suggesting that the cleavage reaction is extremely fast.
  • 44
    • 0038094123 scopus 로고    scopus 로고
    • note
    • -1 at 630 K (ref 22).
  • 45
    • 0038094126 scopus 로고    scopus 로고
    • note
    • -14 (36) at 523 K were estimated.
  • 46
    • 0032070955 scopus 로고    scopus 로고
    • Such a reaction has been identified in the photoinduced polymerization of 4-chloroaniline: Hashimoto, Y.; Mafuné, F.; Kondow, T. J. Phys. Chem. B 1998, 102, 4295-4300.
    • (1998) J. Phys. Chem. B , vol.102 , pp. 4295-4300
    • Hashimoto, Y.1    Mafuné, F.2    Kondow, T.3
  • 47
    • 0038770831 scopus 로고    scopus 로고
    • See ref 6, footnote 25
    • See ref 6, footnote 25.
  • 48
    • 0037756433 scopus 로고    scopus 로고
    • note
    • 3 can be eliminated (through a 1,4-elimination through a six-centered transition state) leading to 20 directly.
  • 49
    • 0038432925 scopus 로고    scopus 로고
    • note
    • DFT, rel (to 4-chloro-aniline, 13) is 3.5 for di(4-chlorophenyl)amine. These relative rates suggest that in experiments with 11 or 13 chlorophenylamines may be observed as reaction products, which is indeed the case, see Table 1 (footnote f).
  • 50
    • 0004133516 scopus 로고    scopus 로고
    • Gaussian, Inc.: Pittsburgh, PA
    • Gaussian 98, revision A.7; Gaussian, Inc.: Pittsburgh, PA, 1998.
    • (1998) Gaussian 98, Revision A.7


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.