Butylated hydroxy-toluene

Di-/ f2 -butyl-4-methylphenol, which is commonly known as BHT (butylated hydroxy toluene), is a widely used phenoHc antioxidant in the stabilization of oils, mbber, and polyolefins (44). BHT is also one of the few phenolic antioxidants approved by the FDA as a direct food additive where it is used to retard the oxidation of naturally occurring oils in food. 

Butadiene reacts readily with oxygen to form polymeric peroxides, which are not very soluble in Hquid butadiene and tend to setde at the bottom of the container because of their higher density. The peroxides are shock sensitive therefore it is imperative to exclude any source of oxygen from butadiene. Addition of antioxidants like /-butylcatechol (TBC) or butylated hydroxy toluene (BHT) removes free radicals that can cause rapid exothermic polymerizations. Butadiene shipments now routinely contain about 100 ppm TBC. Before use, the inhibitor can easily be removed (247,248). Inert gas, such as nitrogen, can also be used to blanket contained butadiene (249). 

Some other inhibitors from the patent literature include hydroquinone [129], ionoP [130], and quinone [131]. Other inhibitors used to stabilize MMA include butylated hydroxy toluene (BHT), phenothiazine, methylene blue, hydroxy-diphenylamine and di-/jc/<3-napthol [132]. Several good reviews of inhibition and inhibitors have been written [133-136]. The mechanisms of inhibition are subtle and complicated. For example, it has been reported that highly purified benzo-quinone acts as a retarder rather than an inhibitor [137]. It has been proposed... 

Examination of the history of antioxidants such as hindered phenols and amines shows a move from low-MW products to higher-MW products. Specifically, polymer industries have abandoned the use of, e.g., butylated hydroxy toluene (BHT) in favor of tetrakismethylene (3,5-di-f-butyl-4-hydroxydrocinnamate)methane (see Figure 15.9). Likewise, polymeric HALS, like poly-methylpropyl-3-oxy-(4(2,2,6,6-tetramethyl)piperidinyl) siloxane, replaced the low-MW hindered amine Lowilite 77 (see Figure 15.10). The next obvious step was to produce a new class of stabilizers. 

The detection and quantification of one or more of the above lipid peroxidation produas (primary and/or secondary) in appropriate biofluids and tissue samples serves to provide indices of lipid peroxidation both in ntro and in vivo. However, it must be stressed that it is absolutely essential to ensure that the products monitored do not arise artifactually, a very difiScult task since parameters such as the availability of catalytic trace metal ions and O2, temperature and exposure to light are all capable of promoting the oxidative deterioration of PUFAs. Indeed, one sensible precaution involves the treatment of samples for analysis with sufficient levels of a chainbreaking antioxidant [for example, butylated hydroxy-toluene (BHT)] immediately after collection to retard or prevent peroxidation occurring during periods of storage or preparation. 

The time-scale of this haem conversion is related to the antioxidant status of the LDL and that of the erythrocyte lysate. The incorporation of lipid-soluble antioxidants, such as tocopherol and butylated hydroxy-toluene (BHT) at specific time points during the LDL-erythrocyte interaction, prolongs the lag phase to oxidation, eliminates the oxy to ferryl conversion of the haemoglobin and delays the oxidative modification of the LDL. 

A carbon treatment also removes residual color. THF proved to be the best solvent for this operation. One antioxidant often used to stabilize commercial TH F is BHT 53 (butylated hydroxy toluene). The carbon promotes oxidation of the BHT to give a yellow dimer 54 (Scheme 3.20). After sufficient washing of the carbon with THF, the dimer is no longer formed. Although the dimer is removed in crystallization of the product, it is best to wash the carbon prior to use. 

I. Jagnandan, H. Daun, T. J. Ambrosio and S. G. Gilbert. Isolation and identification of 3,3,5,5-tetrabis(tert-butyl) stilbenequinone from polyethylene closures containing titanium dioxide and butylated hydroxy toluene. J. Pharm. Sci., 68, 916 (1979). 

Zhang and Nunes [92] studied the structure and the generation mechanism of a novel degradation product formed by oxidatively induced coupling of miconazole nitrate with butylated hydroxy toluene in a topical ointment studied by high performance liquid chromatography-electrospray ionization mass spectrometry and organic synthesis. 

The commonest synthetic antioxidants are butylated hydroxyanisole (BHA) and butylated hydroxy toluene (BHT). Other synthetic antioxidants are w-propyl gallate and n-octyl gallate. Any substance that can act as a radical trap will have antioxidant properties. There are strict rules governing the use of antioxidants in foods. Only those substances that are on the permitted list can be used. 

Ligand 55c is also efficient in the cyclopropanation of other alkenes. 1,1 -Disub-stituted alkenes afford cyclopropanes in high enantioselectivity with ethyl diazoacetate as carbenoid source, Eq. 25 (34). Internal dissymetric trans alkenes are also excellent substrates. trans-P-Methyl styrene afforded a 95 5 diastereomeric mixture with cyclopropane 56a predominating in 96% ee, when the butylated hydroxy toluene (BHT) diazoester was used, Eq. 26 (35). 

BUI Butylated hydroxy toluene (2,6-di-f< rf-butyl-4-methyl-phenol)... 

It should be mentioned that the commercially available VC usually contained a small percentage (<2%) of prohibitors that stabilized the reactive VC from polymerizing upon storage. These compounds were usually radical scavengers such as 2,6-di-tert-butyl-p-cresol (DBC) or butylated hydroxy toluene (BHT). Recently, reports pointed out that the presence of these prohibitors actually had a negative impact on the anodic stability of VC on various cathode materials, and VC of high purity was of vital importance in obtaining reproducible performance in lithium ion cells. 

These are Important and necessaiy food additives. These help in food preservation by retarding the action of oxygen on food. These are more reactive towards oxygen than the food material which they are protecting. The two most familiar antioxidants are butylated hydroxy toluene (BHT) and butylated hydroxy anlsole (BHA). The addition of BHA to butter Increases its shelf life from months to years. 

Some naturally occurring and synthetic food components, furocoumarins and ultraviolet radiation, pp 161-206. Lyon, International Agency for Research on Cancer, 1986 6. Tanaka T, Oishi S, Takahashi O Three generation toxicity study of butylated hydroxy-toluene administered to mice. Toxicol Lett 66(3) 295-304, 1993... 

Many phenols, especially hindered phenols such as butylated hydroxy toluene (BHT), are good antioxidants. They act as radical scavengers by readily reacting with stray radicals to give very stable radicals via resonance. 

The main problem in the vitamin E analysis is that it is easily oxidized, thereby an antioxidant, such as butyl hydroxy toluene (BHT) or ascorbic acid, is added to prevent degradation during the extraction step. The traditional method for extraction of tocopherols and tocotrienols in foods is solvent extraction (like soxhlet) and saponification with KOH [457,458]. Some authors have recently proved that saponification is not necessary [459-462], nevertheless, it has been widely applied until the present day. 

Aromatic alcohols are called phenols. The simplest phenol, also called phenol, forms when a hydroxyl group replaces a hydrogen atom in the benzene ring. Phenol (carbolic acid) was used as an antiseptic in the 1800s. Today other phenol derivatives are used in antiseptic mouthwashes and in cleaning disinfectants such as Lysol. Phenols are easily oxidized, and this makes them ideal substances to use as antioxidants. By adding phenols such as BHT (butylated hydroxy toluene) and BHA (butylated hydroxy anisole) to food, the phenols oxidize rather than the food. 

Figure 5.17 Structure of the food additive butylated hydroxy toluene.

Many naturally occurring antioxidants are found in common foods. These include the green tea catechins,5 6 resveratrol from red wine,7 curcumin from curry powder,8 sul-foraphane from cruciferous vegetables,9 etc. Some synthetic materials are also added to foods to prevent rancidity of lipids. Examples include butylated hydroxy toluene (BHT) and butylated hydroxy anisole (BHA). 

The use of acidulants is an essential part of beverage formulation, with the acid component usually third in order of concentration. Acidulants performs a variety of functions in addition to their primary thirst-quenching properties, which are the result of stimulation of the flow of saliva in the mouth. Because it reduces pH, an acidulant can act as a mild preservative and in some respects as a flavour enhancer, depending on the other components present. In addition, by functioning as a synergist to antioxidants such as butylated hydroxy anisole (BHA), butylated hydroxy toluene (BHT) and ascorbic acid, acidulants can indirectly prevent discolouration and ranciditye. 

Oil-based, water-dispersible flavours (emulsions) are protected by the addition of oil-soluble antioxidants such as butylated hydroxy anisole (BHA) and butylated hydroxy toluene (BHT) to the oil phase before the emulsification process 1,000 mg/1 is the typical usage level in essential oils. Since the flavour emulsion will be used at the rate of about 0.1%, the level of antioxidant in the finished beverage will be of the order of 1 mg/1, which will safely comply with an ADI of 5 mg/kg body weight for either additive. 

Further oxidation of these products can result in the consumption of many equivalents of oxidant for each molecule of DBP. This is the chemistry by which antioxidants protect many commercial products from spoilage or material damage by oxidation (20). Antioxidants such as DBP, and the more familiar BHT (butylated hydroxy toluene or 2,6-di-(t-butyl)-4-methyl phenol), are used very widely, so these compounds and their oxidation products are widely distributed in the environment (21). 

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