2.6- Di-tert-butyl phenol

Fig. 1 Spectra measured 50, 250 and 1000 ps (downwards from the top) upon fs-laser photolysis of 5xl0"3 mol dm"3 2,6-di-tert.-butylphenol (left) or 4-methyl-2,6-di tert.-butyl phenol (right) in pure acetonitrile and in samples containing 1 mol dm"3 water (below).

Example Estimate Tb for 2,6-di(tert-butyl)phenol (molecular weight = 206.33 g/ mol) ... 

Example 4a) Estimate Koc and Kd for 2,6-di(tert-butyl) phenol in a soil containing 4% organic carbon using the Kow value of 5.43 listed in Table 8.7. 

Example 4b) Assuming no experimental values of Kow or S are available, estimate Koc for 2,6-di(tert-butyl) phenol from MCIs using the following expression (Meylan et al., 1992) ... 

Biaryls were obtained by C-alkylation using 2,6-di-tert-butyl phenolate as nucleophile with/rara-chlorobenzonitrile and 2-chloro-5-cyanopyridine676. Bromobenzonitriles and bro-mocyanopyridines have been employed in a study in which it was demonstrated that these compounds can be successfully used to arylate monoanions of / -dicarbonyl compounds677. 

The molecular structure of the polymer additive IRGANOX 1076 with Mr i = 531 is shown in Appendix III. To calculate the IRGANOX/ethanol partition coefficient use Eq. (4-103) and Table 4-8. Two structural increments are considered Wj(p/L> = 180 for ester and Wj(P/L) = 140 for the 2,6-di-tert-butyl-phenol ... 

To calculate the IRGANOX/water partition coefficient use Eqs. (4-98), (4-101) and (4-50) in combination with Table 4-6. The average-value Wj(G/p> = -4 is used for the ester increment in LDPE. For the 2,6-di-tert-butyl-phenol increment no value can be extracted from Table 4-6. But comparing the increments in Table 4-8 one half of the value for primary-alcohol is taken and one can use Wj(G/p) = 10 for LDPE. A four-fold branching has to be considered and this gives Wj(G/P) = 4 x (-5) = -20 (as average) ... 

Kawasaki et al.40 disclosed the use of hindered phenols such as 2,6-di(tert-butyl)phenol as stabilizers for spirooxazines in poly (vinyl butyral). The hindered phenols not only improved photochromic durability but also photochromic response, besides accelerating the thermal recovery rate. 

Cl4Hl8BrN04 (R)-N-boc-3-amino-3-(4-bromophenyl)propanoic 261380-20-5 25.00 1.3898 2 27617 C14H21BrO 4-bromo-2,6-di-tert-butyl phenol 1139-52-2 25.00 1.1880 2... 

The general procedure for the coupling of styrenes with bromo- and chloroarcnes [16] is exemplified by this preparation (Scheme 3-56). In a 100-mL three-necked flask equipped with a reflux condenser, stirrer, and internal thermometer were placed, under a stream of nitrogen, 4-bromoacetophenone (23a-Br) (5.0 g, 25 mmol) [or 4-chloroacetophenone (23a-Cl) (3.3 mL, 3.9 g, 25 mmol) plus TBABr (1.64 g. 5 mmol)], styrene (4.3 mL, 3.9 g, 37 mol), 2,6-di(tert-butyl)phenol (20 mg, as a radical scavenger), NaOAc (2.5 g, 30 mmol), and A(A-dimethylacetamide (50 mL). To the well-stirred suspension was added 12 mg (0.1 mol%) of the palladacycle la, and the mixture was heated at 130 "C for 24 h (54 h with 4-chloroacetophenone). After the reaction mixture had cooled to rt, it was poured into ice-water (200 mL). The precipitate was collected on a filter, carefully washed with water and recrystallized from acetone/water to yield 4.9 g (89%) of 258a (3.8 g, 69% from 4-chloroacetophenone). 

Oxidation of 2,6-di(tert-butyl)phenol (23) provides a useful test for comparing the activity of various catalysts 23 is oxidized with O2 catalyzed by metal-amine complexes to give only two products, 2,6-di(terr-butyl)-p-benzoquinone (74) and 3,3, 5,5 -tetra(ferf-butyl)diphenoquinone (24) (Scheme 46). Of the cobalt catalysts 230, 231, 232 and 237, the use of Co(salN-Medpt) in MeCN (room temp., 1 h) provided the most effective results, in which 74 was obtained in 100% yield. The oxidation rate and yield were dependent on... 

Oxidation of 2,6-di(tert-butyl)phenol (23), both ortfjo-positions of which are blocked by the bulky tert-butyl groups, was effected with 4 equivalents of methyl(trifluoromethyl)dioxirane (553) at 0°C for 1 min to afford three oxygenated products (554, 74 and 555) in 4, 24 and 70% yields, respectively. Dimethyldioxirane-promoted oxidation of 23 required much longer reaction time (48 h) to yield the... 

SCHEME 139. Oxidation of 4-acetylenic 2,6-di(tert-butyl)phenol with K3pe(CN)6 or Pb02... 

A characteristic feature of Ti-UTD-1 which we would like to exploit is the 14 membered ring system where substrates too large for other zeolites can effectively be oxidized. The large 2,6-di-tert-butyl phenol (2,6-DTBP) has been used as a susbtrate for titanium containing mesoporous molecular sieve catalyzed oxidations [IS] to yield the corresponding quinone as shown in Scheme 3 below. Table 4 shows the results for 2,6-DTBP oxidation at 6S°C using H2O2 as the oxidant in acetone solvent. The selectivity to the quinone... 

The novel zeolite UTD-1 with titanium in the framework (up to 3.5% by weight) is an effective catalyst for the oxidation of cyclohexane, cyclohexene and 2,6-di-tert-butyl phenol. The catalytic behavior is similar to that of other large pore zeolites and mesoporous molecular sieves modified with titanium which includes solvents effects. Additionally, Ti-UTD-1 allows the use of oxidants and substrates too large for the commercial TS-1 catalyst. We are currently evaluating further the role of solvent and oxidant in an effort to improve selectivity as well as expand the utility of this material in oxidation catalysis. 

Insbesondere Bis-[dimethylamino]-tert.-butyloxy-methan92,93 reagiert bei 100-120° mit a-Naphthol und 2,6-Di-tert.-butyl-phenol zu Aldehyd-diaminoacetalen, die bei der Hydrolyse 2-Formyl-l-hydroxy-naphthalin (62%) bzw. 3,5-Di-tert.-butyl-4-hydroxy-benz-aldehyd ergeben94. Die Methode bedarf hinsichtlich Reaktionsbedingungen und Anwen-dungsbreite der Bearbeitung ... 

Photolytische Brom-Abspaltung von 4-Brom-2,6-di-tert.-butyl-phenol in Benzol ftthrt wahrscheinlich fiber Phenoxy-Radikale zu 2,2, 6,6 -Tetra-tert.-butyl-diphenochinon (43,2% d.Th.) neben 2,6-Di-tert.-butyl-phenol ( 4% d.Th.) und 4-Hydroxy-3,5-di-tert.-btdyl-biphenyl (8% d.Th.)8 ... 

An induction period was observed in the decomposition of cumyl hydroperoxide in chlorobenzene at 70 and 110 °C in the presence of phenolic sulphides CXCVIIa,b262). This was a substantial difference with respect to the behaviour of 4,4 -thio-bis(2,6-di-tert-butylphenol) CLXVIIIb which decomposed ROOH under the same conditions without induction period. The result indicates a mechanistic distinction in the action of both types of phenolic sulphides. In the mechanism of transformations of benzyl sulphide CXCVIIb, there are assumed (Scheme 24) the formation of sulphoxide CXCVIII and the intermediary formation of CIC followed by oxidation and formation of sulphinic acid CC. Further transformation of the acid CC depends on the character of R. If R = 3,5-di-tert-butyl-4-hydroxybenzyl, as it is in the formation of CC from CXCVIIa, the total elimination of the sulphurous part of molecule may occur and the transformation products of phenolic or quinoid character may be formed 3,5-di-tert-butyl-4-hydroxybenzyl alcohol XXXI, the corresponding aldehyde XXXII, and 2,6-di-tert-butyl-l,4-benzoquinone XXII were identified. Another possible sulphurless product is 4,4 -ethylenebis(2,6-di-tert-butyl-phenol) XXVIII, which was isolated in small amounts in its oxidized form as 3,5,3 ,5 -tetra-tert-butyl-4,4 -stilbenequinone (XXIX). Quinone methide XXX formed by thermolysis of sulphoxide CXCVIII, may be also the precursor in formation of XXIX. According to66), XXX is further oxidized by hydroperoxides to XXIX... 

A comparison of phenolic coupling on solid potassium permanganate and on potassium manganate surfaces has been made to emulate the natural biological process (ref.4). Diphenoquinone formation in more than 90% yield was observed with the oxidation of 2,6-dimethyl, 2,6-di-isopropyl, and 2,6-di-tert-butyl phenol (R = Me,i-Pr,t-Bu) in chloroform solution on (a) solid potassium permanganate whereas underthe same conditions (b) potassium manganate. 

In this section the reactions of 2-tert-butylated and 2,6-di-tert-butylated phenols recently described are considered. The former, the cryptophenols are not completely hindered like the 2,6-di-tett-butylphenols although their reactions are different from those of 2-methylphenols. In both groups the reactions are comparatively straightfonward and comprise substitution or oxidation either at the phenolic oxygen or at the carbon in the 4-position. 

Parafoimaldehyde (2 moles) and 2,6-di-tert-butyl-phenol and catalyst, 10% Pd-C and ytterbium chloride hydrogenated (7Kg/cmT) at ambient temp, to give 2,6-di-tert-butyl-4-methylphenol. 

Oxidative dimerization of 2,6-di-tert-butyl phenol to 3,3 5,5 -tetra- er butyl biphenol (TBBPL) and subsequent debut-ylation. 

Tetrahydrofuran (THF, tetramethylene oxide, diethylene oxide, 1,4-epoxybutane, tetrahydrofurane, oxoiane) is an industrial solvent widely recognized for its unique combination of useful properties. DuPont THF is better than 99.9% pure with a small (0.025-0.040 wt %) amount of butylated hydroxytoluene (BHT, 4-methyl-2,6-di-tert-butyl phenol) added as an antioxidant. Tetrahydrofuran is a cycloaliphatic ether and is not "photochemically reactive" as defined in Section k of Los Angeles County s Rule 66 (equivalent to Rule 442 of the Southern California Air Pollution Controi District). THF has an ethereal odor. 

Hydroquinone (HQ) is prepared by the oxidation of phenol. Resorcinol can be prepared by the oxidation of m-diisopropylbenzene. Biphenol is prepared by the oxidative dimerization of 2,6-di-tert-butyl phenol and subsequent debutylation [19]. 

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