2.4.6- Tri-t-butylphenol

Although limited by sensitivity, chemical reaction monitoring via less sensitive nuclei (such as 13C) has also been reported. In 1987 Albert et al. monitored the electrochemical reaction of 2,4,6-tri-t-butylphenol by continuous flow 13C NMR [4]. More recently, Hunger and Horvath studied the conversion of vapor propan-2-ol (13C labeled) on zeolites using 1H and 13C in situ magic angle spinning (MAS) NMR spectroscopy under continuous-flow conditions [15]. 

An ESR spectrum of the electrolysis solution of 2,4,6-tri-t-butylphenol showed the formation of phenoxy radical which was accumulated in the solution with the supplied current amount. The active species of polymerization reaction was assumed to be a phenoxy radical formed by the electrolysis. 

It has been shown that mononuclear cobalt superoxo complexes react with 2,4,6-tri-t-butyl-phenol. The anion [Co(CN)5(02)]3 acts as a base in the oxidation of the phenol. The neutral complex Co(salptr)(Oz) forms a peroxy adduct with 2,4,6-tri-t-butylphenol. An X-ray study on this adduct has revealed the structure shown in (10).m... 

SbClj has been claimed to act as an electron-transfer oxidant toward a number of reagents, such as N,N,N, N -tetramethylphenylenediamine, triphenylamine, 2,4,6-tri-t-butylphenolate ion, ferrocene, and N-vinylcarbazole. Among these, triphenylamine is the most difficult to oxidize, and was therefore chosen as a model compound in entry no. 18. By matching the lowest possible experimental rate constant, 103 s , with rate constants calculated as a function of E° for the SbClj/SbCl - couple, the latter was estimated to be 0.54 V. This is an entirely reasonable value (see Cowell et al., 1970). 

A predominant factor in determining the distinct behaviour of hindered compounds is most probably the strain between the neighbouring groups. The strain energy in 2,4,6-tri-t-butylphenol was calculated as 8 kcal mole-1 while no such energy has been indicated for... 

Aryl substituents in either the 2- or 2,6-position cause a downfield shift of the OH stretching frequency in CCI due to the formation of an intramolecular hydrogen bond to the aromatic ring 170) (phenol 3605 cm-1, 2-phenylphenol and 2,6-diphenyl-phenol 3555 cm "1 2,4,6-triphenylphenol 3553 cm-1). Under the same conditions t-butyl-phenols give rise to higher frequencies (2,6-di-t-butylphenol and 2,4,6-tri-t-butylphenol 3645 cm-1, compared with phenol 3612 cm-1)171). 

Other careful electrochemical measurements of the oxidation potentials of 2,4,6-tri-t-butylphenol and 2,6-di-t-butyl-4-methylphenol in acetate buffered ethanol or acetonitrile have been measured by Mauser et al.184). They determined the static potentials using a boron carbide indicator and a mercury/mercury-acetate reference-electrode. Since in this case the oxidation of the phenols and not the phenolates to the phenoxyls has been determined the oxidation potentials cannot be compared with those in Table 12. For other electrochemical oxidations of phenols in buffered aqueous solutions using a graphite electrode see Ref. 185 186>. 

Further insight into the quenching mechanism came from a variable temperature study which employed the time-resolved bleaching of DPBF to monitor 02(1Ag) reactivity towards a-tocopherol (10), 6-hydroxy-2,2,5,7,8-pentamethylchroman (11) and 2,4,6-tri-t-butylphenol (12) in a range of... 

A somewhat more unusual case is the positive proton enhancements observed for the t-butyl groups of 2,4,6-tri-t-butylphenol in solutions containing the corresponding phenoxyl radical. In these solutions there is a proton exchange reaction—... 

Alkofen B 2,4,6-Tri-t-butylphenol 2,4,6-Tri-tert-butyl-1-hydroxybenzene 2,4,6-Tri-tert-butylphenol CCRIS 5845 2,4,6-Tris(1,1-dimethylethyl)phenol EINECS 211-989-5 NSC 14459 P 23 Phenol, 2,4,6-lri-tert-butyl- Phenol, 2,4,6-tris(1,1-dimethylethyl)- TM02 Tris(1,1-dimethyl-ethyl)phenol Voidox. Solid mp = 131° bp = 278° (P = 0.864 Xm = 280 nm (cyclohexane) insoluble in H2O, alkali, soluble in EtOH, Me2CO, CCI4. 

The dihydric phenols are speciality products widely used industrially and commercially. Hydroquinone and its relative, 4-methylaminophenol (metol) are the main chemicals used for development in black and white photography. Butylated hydroxyanisole, (BHA) mainly 2,6-di-tert-butyl-4-methoxyphenol (5), an important food antioxidant is synthesised from 2,4,6-tri-t-butylphenol by reaction in methanolic solution with chlorine to give 2,4,6-tri-t-butyl-4-methoxy-... 

Tetramethylbenzene 2,4,6-Tri-t-butylphenol 0,0,0-Tributyl phosphorothioate Tributyrin Tricapryl citrate Tri-m,p-cresyl borate Triethyl phosphite ... 

The catalytic oxygenation of 2,4,6-tri-t-butylphenol (la) can be observed in methanol at room temperature. In cold MeOH (0 C) or in CH2CI2 at room temperature a para-peroxycobalt complex (17) is obtained... 

Of special interest is the oxidation of 2,4,6-tri-t-butylphenol (TTBP), which yields 4 products in addition to the corresponding p-benzoquinone (Scheme 1). 

The above mechanistic scheme developed for 2,4,6-tri-t-butylphenol may also be extended to 4-alkyl derivatives. 

Figure 5.1 UV spectra 2,4,6-tri-t-butylphenol solution in the course of NO bubbling (1), after completion of 15 hours of bubbling (2), after 10 minutes of...

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