2.6- Di-t-butyl-4-methylphenol

Furthermore, the reaction of several hindered phenols, such as 2,6-di-t-butyl-4-methylphenol, 3,5-di-t-butyl-4-hydroxybenzyl alcohol, and 2,6-di-t-butylphenol, with BTMA Br3 were carried out in dichloromethane in the presence of water, t-butyl alcohol, or aq. sodium hydroxide at room temperature. Sequential reaction processes were provided by the obtained products. As an example, we show the reaction of 2,6-di-t-butyl-4-methylphenol with BTMA Br3 in Fig. 26 (ref. 34). 

Irganox 1076 [octadecyl-3-(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,6-di-t-butyl-4-methylphenol and diisooctyl phthalate were analyzed by GPC interfaced with both electrospray mass spectrometry (ESI-MS) and NMR.1 A deuterochloroform solvent was used. It was noted that a parallel arrangement was necessary to avoid backpressure on the NMR flow-probe that can... 

Bisglycidylacrylate, ethoxylated bisphenol A dimethacrylate, diurethane dimethacrylate, triethyleneglycol dimethacrylate, tricycle[5.2.1.02,6]decanedimethanol diacrylate, camphorquinone, ethyl 4-(/V,/V-dimcthylamino)benzoate, diphenyl iodonium hexafluorophosphate, 2,6-di-t-butyl-4-methylphenol, benzotriazole... 

Degradation in solution. Davis and Golden (85) found that the viscosity of a benzene solution of PTHF heated in air dropped steadily in the absence of anti-oxidant with eventual complete destruction of the polymer. In the presence of anti-oxidant (e. g. 0.5% 2,6-di-t-butyl-4-methylphenol) the viscosity fell initially but thereafter became constant. As shown in Fig. 29, this initial drop was greater for polymer A... 

All UV spectral data were obtained by measurement using a conventional UV / vis spectrometer (HP8458) with either aqueous or acetonitrile solutions of the benchmark chemicals. The spectrum of DBP was assumed to be the same as the spectrum of 2,6-di-t-butyl-4-methylphenol. Since DBP differs from this compound by only a para methyl group, the assumption of identical spectra is a good approximation and the absence of absorbance above 300 nm quite certain. Values of were calculated from the absorption at the wavelength centers X (shown in Table 15.1, and the concentration using Equation (2). 

BHT is used to prevent the oxidation of vitamins A and E in foods. It carries the E-number E321. There has been some controversy over its use because it is a cancer suspect agent, but it is used in some foods like chewing gum. BHT stands for Butylated HydroxyToluene you can call it 2,6-di-t-butyl-4-methylphenol if you want to, but you may prefer to look at the structure and just call it BHT, You met BHT briefly in Chapter 2 when you were introduced to the tertiary butyl group. 

Although the fluoride ion is normally a very strong hydrogen-bond acceptor, the adduct formed between tetra-n-butylammonium fluoride and 2,6-di-t-butyl-4-methylphenol contains a weak F - H—O bond with... 

Two of the abstraction reactions listed in Table 6 will be discussed further viz. (a) the reaction of n-heptyl radicals with tetramethyl-ethylene which was studied specifically to help elucidate the conditions under which the reactions take place and (b) the reaction of peroxy-radicals with an oxidation inhibitor 2,6-di-t-butyl-4-methylphenol (lonol) which is of particular interest in that two distinct mechanisms have been proposed to account for its antioxidant properties. 

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>. 

Metal-carbon bonds in some Zn and A1 porphyrins, e.g., N-methyltetra-phenylporphinatozinc ethyl and tetraphenylporphinatoaluminium ethyl, can be activated photochemically and undergo substitution reactions with hindered phenols such as 2,6-di-t-butyl-4-methylphenol and 2,6-di-t-butyl-4-methoxy-phenol. The products are metalloporphyrins having a phenoxy-group bound to Zn or Al. Photoexcitation is thought to increase the electron density of the ethyl group bound to the central metal atom and this brings about an enhanced nucleophilicity of the metal-carbon bond. " ... 

Common radical inhibitors include 2,6-di-t-butyl-4-methylphenol (BHT), 2-nitroso-2-propane, and oxygen. 

Because of the ease with which THF forms peroxides, it is normally shipped and stored in the presence of a stabilizer such as 2,6-di-t-butyl-4-methylphenol (butylated hydroxytoluene, BHT). In addition, THF readily absorbs water and oxygen. Inasmuch as these impurities are detrimental to polymerization, it is imperative to purify the THF before it can be used as a polymerization monomer. 

FIGURE 1. Oxygen uptake profiles for oxidation of 0.12 M methyl hnoleate in 0.5 M SDS micelles, initiated by 0.03 M of the thermal azo initiator di-tcrt-butylhyponitrite, comparing the effects of the retarder melatonin (R) with phenolic antioxidants U—uninhibited oxidation, R1— 8.72 X 10-5 melatonin, R2—87.2 x 10-5 melatonin, a-Toc—8.72 x 10-5 a-Toc, nib—8.72 x 10 5 M BHT [butylated hydroxytoluene (2,6-di-t-butyl-4-methylphenol)], Vc—8.72 x 10 5 M Trolox (2,5,6,7-tetramethyl-2-carboxy-5-hydroxychroman), Va—8.72 x 10-5 PMHC (2,2,5,6,7-pen-tamethyl-5-hydroxychroman). Reproduced by permission of Elsevier Science from Reference 283... 

A recent brief study of the photochemistry at 254 nm in tetrahydrofuran (THF) of the fluorinated 1,2-diphenylethane derivatives, 100, reported very low and inefficient conversions to the corresponding stilbene derivatives, Eq. (36) [138]. The addition of a radical inhibitor, 2,6-di-t-butyl-4-methylphenol, had no effect. The mechanism for the loss of hydrogen fluoride is therefore not known. Irradiation in the presence of LiAlHt gave reduction products and the mechanism proposed begins with electron transfer from the hydride to the excited state of the substrate to form a radical ion pair. 

We also have attempted to inhibit these free radical reactions with 2,6-di-t-butyl-4-methylphenol and found no effect on the formation of cyclohexanol or cyclohexanone using catalyst 4. This latter result strongly suggests that peroxyl, alkoxyl, or hydroxyl radicals are not intermediates in these reactions. The intermediacy of a putative oxo-manganese complex is further strengthened by the reaction of 1-4 with cyclohexene in the presence of TBHP or iodosylbenzene to provide cyclohexene epoxide and our proposed mechanism is shown in the Equation (2). w H... 

U.V. Stabilizers.—Many of the papers discussed in preceding sections contain discussion of the nature and mechanism of u.v. stabilizers. A brief survey of antioxidants and stabilizers used in the plastics industry has appeared,28 and some new photostabilizers, including a polymeric u.v. absorber and a surface-grafted antioxidant, have been proposed.280 The mechanism of nickel chelate stabilizers has been further discussed,281 and the diffusion of and loss of light stabilizers in poly(olefins) described.282 As part of an attempt to understand the transformations of stabilizers during the ageing of polymers, the photooxidation of 2,6-di-t-butyl-4-methylphenol sensitized by Methylene Blue has been studied.283 U.v. light protection by sunscreens, with mechanisms of interest to the polymer field, has been described.284... 

Alts. The loose bottle cap allows the entry of moisture, oxygen, and bacteria which accelerate hydrolysis and oxidation. Tightening the cap and refrigerating the substance slows the rancid reactions. Some manufacturers of vegetable oils add phenol derivatives, such as BHT (butylated hydroxytoluene lUPAC 2,6-di-t-butyl-4-methylphenol), BHA (butylated hydroxyanisole lUPAC 2-/-butyl-4-methoxyphenol), and vitamin E, which act as antioxidants. 

The butterfly pheromone (18) was previously prepared by the oxidation of the necine base supinidine (17) (Scheme 4). A simple synthesis of this pheromone has now been reported by Pizzorno and Albonico. Regiospeciflc 1,3-cycloaddition of propargylic aldehyde with the postulated azomethine ylide intermediate (19), formed by refluxing N-formylproline in acetic anhydride with 2,6-di-t-butyl-4-methylphenol as anti-oxidant, gave a 40% yield of the dihy-dropyrrolizine (18). 

Phenolics are the most widely used antioxidants in plastics and are added to polyethylene and polystyrene and its copolymers. They may form coloured degradation quinine products on oxidation. The most widely used phenolic is butylated hydroxytoluene (BHT), which has an lUPAC name 2,6-di-t-butyl-4-methylphenol. BHT is added to many polymers including those used for food... 

Synonyms 2,6-Bis (1,1 -dimethylethyl)-4-methylphenol Butylated hydroxy-toluene DBPC 2,6-Di-t-butyl-p-cresol 2,6-Di-t-butyl-4-methylphenol Hydroxytoluene, butylated 4-Methyl-2,6-di-t-butylphenol Methyl di-t-butylphenol... 

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