2.6- Di-fert-butylphenol

Hydroxymethyl-2,6-di-fert-butylphenol Propyl gallate Stannous chloride TBHQ (tertiarybutylhydroquinone)... 

One final anomaly we have already commented on the enhanced value for the effect of para-substituents on the ionization of 2,6-di-fert-butylphenol in 1 1 v/v Et0H-H20 at 25 °C (Section III.D). In this solvent phenol itself has a p/fa value of 11.16, and the values for the 4-NO and 4-NO2 derivatives are 6.9 and 7.49, respectively134, i.e. NO has a greater acid-strengthening effect on phenol than NO2 does, as we have already seen above for solutions in water. However, the p/fa values of 2,6-di-fert-butylphenol and its 4-NO and 4-NO2 derivatives in 1 1 v/v Et0H-H20 are 14.22, 9.41 and 7.49, respectively134, i.e. the acid-strengthening effects of NO and NO2 are reversed. The apparent a value of p-NO is now about 0.9. Presumably there is a considerable amount of quinonoid form in this system. 

A similar reaction of i -Bu2Mg with 2,6-di-fert-butylphenol in the presence of 18-crown-6 affords i-BuMgOC6H3Bu-r-2,6(18-crown-6) (209) as a crystalline solid. An X-ray crystal-structure determination showed that this compound in the solid state also exists as a monomer with a a-bonded i-butyl group and a a-bonded phenoxy oxygen atom. Three adjacent oxygen atoms of the crown-ether are involved in coordination to magnesium, resulting in penta-coordination. 

They synthesized IV independently and found it to be bright yellow. We have found that rubber samples containing 4,4 -methylenebis(2,6-di-fert-butylphenol) tend to turn yellow on aging and that, in some cases, films laid from high pH latexes have turned purple on heat aging. 

A cobalt complex salcomine (7.39) oxidizes substituted phenols but unsubstituted at para position, such as 2,6-di-fert-butylphenol (7.40), to give the corresponding p-quinone, 2,6-di- tert-butyl-p-benzoquinone (7.41). 

V. N. Komissarov, V A. Kharlanov, L. Yu. Ukhin, E. Yu. Bulgarevich, and VI. Minkin, Photo-and thermochromic Mannich bases. Derivatives of 2,6-di-fert-butylphenol and aromatic ortho-hydroxy aldehydes, Zh. Org. Khim. 28,513-517 (1992). 

Quantum-chemical calculations by the method of Hartrii-Focks with parameters UHF and RHF 4-replaced 2,6-di-ferf.butylphenol values energy homolytic dissociation 0-H of communications - D jj are found Value energy formation and energy of homolytic cleavage D communications in molecules phenols depend on calculation approach M6 or PM3) and parameters of a method of Hartrii-Focks. There are dependences D from k reactions 4-substituted investigated 2,6-di-fert.butylphenol with iso-propylbenzene peroxide compound. Results of calculations D (Q of sterically hindered phenols in approach PM6 with parameter RHF are corrected to experimental data. 

Reaction constants peroxy radical of wo-propylbenzene with 4-Z-re-plased -2,6-di-fert.butylphenols (k ) defined in conditions inhibiting oxidations /50-propylbenzene by oxygen at 50°C in presence azodiisobutyro-nitrile. 

Special attention must be given to TP-7, the molecule of which contains two bulky substituents at the o,d -positions. assume that TP-7 belongs to sterically hindered phenol. 2,6-di-terf-butylpenols are a classical example of these. The decrease in the rate constant k in comparison to 2-te/T-butyl-substituted analogs is characteristic. The antiradical activity of 2,6-di-fert-butylphenol is approximately fourfold lower than that for 2-tert-bulylphenol (k = 0.96x10 and 4xl0 l/(mol s), respectively) [17]. If TP-7 with isobornyl... 

Synergism is observed when binary mixtures of some phenols and aromatic amines are introduced into hydrocarbon. It is related to the interaction of inhibitors and radicals formed from them. For the combined introduction of phenyl-N-P-naph-thylamine and 2,6-di-fert-butylphenol into oxidized ethylbenzene (v, = const, 343 K), phenol is consumed first, and amine begins to consume only after its disappearance, although RO 2 reacts with amine more rapidly (A31 = 1.3T0 l/(mol s), 333 K) than... 

Synergism was observed for the cranbined introduction of two phenols, one of which is necessarily 2,6-di-fert-butylphenol. The initiated oxidation of 9,10-dihy-droanthracene is not almost retarded by 2,4,6-tri-/crt-butylphenol (lO mol/1 at 333 K) but -methoxyphenol in the same concentration retards oxidation. The induction period is doubled if both phenols are introduced in the same concentration, that is, both phenols participate in chain termination if they are introduced in combination. This is explained by the exchange reaction... 

Anodic oxidation of 2,6-di-tert-butylphenols (35) in acetonitrile or acetonitrile-perchloric acid leads to 7-tm-butyl-2-methylbenzoxazoles (36). In the absence of nucleophiles, the initially formed cation 37 adds acetonitrile to give 38, which loses a fert-butyl cation, [Eq. (41)].87... 

The effects of various parameters on the ferf-butylation of phenol on the ZeoUte-H-beta have been studied". Alkylation of phenol in the vapor phase using Zeolite SAP-11 and ferf-butyl alcohol gives the ortho- and para-ferf-butylphenols, together with the 2, 6-di-ferf-butylphenol (equation 22). Vapor-phase alkylation of phenol with tert-butyl alcohol over solid superacid catalysts, such as sulfated zirconia" and mesoporous H-AMCM-41, gives para-fert-butylphenol as a major product in high regioselectivity. 

Di-fert-butyl-a-dimethylamino-p-cresol 2,2 -Methylenebis(4-methyl-6-tert-butylphenol) 2,2 -Methylenebis(4-ethyl-6-tert-butylphenol) 4,4 -Butylidenebis(3-methyl-6-fCT t-butylphenol) 4,4 -Methylenebis(2,6-di-tert-butylphenol) 4,4 -Bis(2,6-di-tert-butylphenol)... 

Thio[diethyl-3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] 3,9-Bisl,l-dimethyl-2-[3-(3-tert-butyl-4-hydroxy-5-methylphenyl)-propionyloxy]ethyl-2,4,8,10-tetraoxaspiro[5,5]undecane l,l/3-Tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane l,3/5-Trimethyl-2,4,6-tris(3,5-di-tert-butyl-4-hydroxybenzyl)benzene Bis[3,3 -bis(4 -hydroxy-3 -tert-butylphenyl)butyric acid] glycol ester 2-(3, 5 -di-fert-butyl-4-hydroxyphenyl)-methyl-4-(2,4-di-tert-butyl-3-hydroxyphenyl)methyl-6-tert-butylphenol... 

Figure 12.7 Chromatograms of a polycarbonate sample (a) microcolumn SEC trace (b) capillary GC trace of introduced fractions. SEC conditions fused-silica (30 cm X 250 mm i.d.) packed with PL-GEL (50 A pore size, 5 mm particle diameter) eluent, THF at a Flow rate of 2.0ml/min injection size, 200 NL UV detection at 254 nm x represents the polymer additive fraction transferred to LC system (ca. 6 p,L). GC conditions DB-1 column (15m X 0.25 mm i.d., 0.25 pun film thickness) deactivated fused-silica uncoated inlet (5 m X 0.32 mm i.d.) temperature program, 100 °C for 8 min, rising to 350 °C at a rate of 12°C/min flame ionization detection. Peak identification is as follows 1, 2,4-tert-butylphenol 2, nonylphenol isomers 3, di(4-fert-butylphenyl) carbonate 4, Tinuvin 329 5, solvent impurity 6, Irgaphos 168 (oxidized). Reprinted with permission from Ref. (14).

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