Butylated hydroquinone

Antioxidants are not important only to the health conscious food manufacturers also rely on these chemicals to maintain the shelf life of their products. Synthetic antioxidants such as butylated hydroxyanisole, butylated hydroxytoluene, propyl gallate and tert-butyl hydroquinone were widely used in food processing to control oxidation and maintain food quality. However, as these synthetic antioxidants are suspected to be carcinogenic they now have restricted use in food (Madahavi and Salunkhe, 1995). Therefore, natural antioxidant sources, especially of plant origin, are of great interest to the food industry. 

A paired-ion, reversed-phase high-performance liquid chromatographic method was developed for the simultaneous determination of sweeteners (dulcin, saccharin-Na, and acesulfame-K), preservatives (sodium dehydroacetate, SA, salicyclic acid, BA, succinic acid, methyl-para-hydroxybenzoic acid, ethyl-para-hydroxybenzoic acid, n-propyl-para-hydroxybenzoic acid, n-butyl-para-hydroxybenzoic acid, and isobutyl-para-hydroxybenzoic acid), and antioxidants (3-tertiary-butyl-4-hydroxyanisole and tertiary-butyl-hydroquinone). A mobile phase of acetonitrile-50 ml aqueous tr-hydroxyisobutyric acid solution (pH 4.5) (2.2 3.4 or 2.4 3.6, v/v) containing 2.5 mM hexadecyltrimethylammonium bromide and a Clg column with a flow rate of 1.0 ml/min and detection at 233 nm were used. This method was found to be very reproducible detection limits ranged from 0.15 to 3.00 p,g. The retention factor (k) of each additive could be affected by the concentrations of hexadecyltrimethylammonium bromide and a-hydroxyisobu-tyric acid and the pH and ratio of mobile phase. The presence of additives in dried roast beef and sugared fruit was determined. The method is suitable for routine analysis of additives in food samples (81). 

The last of the butyl isomers, the tert-butyl compound, was made from a much more obvious starting material. This is the commercially available tert-butyl hydroquinone. It was methylated in sodium hydroxide with methyl iodide, and then carried through the above sequence (benzaldehyde. mp 124 °C from cyclohexane, nitrostyrene, yellow crystals from methanol, mp 95-96.5 °C, and lithium aluminum hydride reduction) to give 2,5-dimethoxy-4-(l,l-dimethylethyl)amphetamine hydrochloride (DOTB, mp 168 °C). Rats trained in a process called the Sidman Avoidance Schedule gave behavior that suggested that DOTB had no activity at all, and in human trials, doses of up to 25 milligrams were totally without effect. 

Antioxidants form only a minor group of cosmetic allergens. Examples are propyl gallate, octyl gallate,66 which may cross-react with other gallates and are also used as food additives, and t-butyl hydroquinone, a well-known allergen in the United Kingdom but not in continental Europe.2... 

Stock Solutions Transfer about 50 mg each of hydroquinone (HQ), 2,5-di-tcrt-butyl hydroquinone (DTBHQ), and methyl benzoate (internal standard), accurately weighed, into separate 50-mL volumetric flasks, dilute to volume with pyridine, and mix. 

Figure 2-18 Structure of Propyl Gallate (PG), Butylated Hydroxyanisole (BHA), Butylated Hydroxy Toluene (BHT), and Tert-Butyl Hydroquinone (TBHQ)...

Primary antioxidants terminate free radical chains and function as electron donors. They include the phenolic antioxidants, butylated hydroxyanisole (BHA), butylated hydroxy-toluene (BHT), tertiary butyl hydroquinone (TBHQ), alkylgalates, usually propylgallate (PG), and natural and synthetic tocopherols and tocotrienols. 

Dihydroxybenzene (hydroquinone), 2-methyl-, 2,3-dimethyl-, and 2-t-butyl-hydroquinones, 1,2-dihydroxybenzene (catechol), ( 1 g each) methanol NaOH pellets. 

Synthetic antioxidants, such as butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propyl gallate (PG), ascorbyl palmitate, and tertiary-butyl-hydroquinone (TBHQ), are used in soybean cooking oils and frying fats (230). These antioxidants are typically added at 0.01% for one antioxidant and 0.02% total for two or more. Natural antioxidants, derived from sage, rosemary, and green tea, are increasingly popular because of consumer preferences for natural food ingredients (231). 

Monomers and catalysts. The monomers methylhydroquinone (MHQ), t-butyl-hydroquinone (BHQ), resorcinol (RO), hydroquinone (HQ), diphenyl carbonate and catalyst tetrabutyl titanate (TBT) were purchased (Aldirch) and used as received. 

Kang KW, Cho MK, Lee CH, Kim SG. 2001. Activation of phosphatidylinositol 3-kinase and Akt by lert-butyl-hydroquinone is responsible for antioxidant response element-mediated rGSTA2 induction in H4IIE cells. Mol. Pharmacol. 59 1147-56... 

Beilstein Handbook Reference) AI3-61039 Banox 20BA 1,4-Benzenediol (1,1-di-methylethyl)- 1,4-Benzenediol, 2-(1,1-dimethylethyl)- BRN 0637923 tert-Butyl-1,4-benzenediol 2-tert-Butyl-1,4-benzenediol Butylhydroquinone, tert- t-Butyl hydroquinone tert-Butylhydroquinone tertiary-Butylhydroquinone 2-t-Butylhydroquinone 2-tert-Butylhydroquinone 2-tert-Butyl(1,4)hydroquinone CCRIS 1447 2-(1,1-Dimethylethyl)-1,4-benzenediol Eastman MTBHQ EINECS 217-752-2 HSDB 838 Hydroquinone, t-butyl- Hydroquinone, tert-butyl- Mono-tert-butylhydroquinone Mono-tertiary butyl-hydroquinone MTBHQ NSC 4972 Sustane Sustane TBHQ TBHQ Tenox TBHQ. Preservative and antioxidant for foodstuffs and meat products color stable and useful as substitute for reactive antioxidants that tend to form purple complexes with iron or copper. White to light tan crystal solid soluble in organic solvents slightly soluble in water mp = 126.5-128,5 LD50 (rat orl) = 700 mg/kg, AC Ind, Inc Aceto Corp. Allchem Ind. Charkit Eastman Chem. Co. Lancaster Synthesis Co. Penta Mfg. Showa Denko UOP. 

Benzoquinones and hydroxybenzoquinones are formed from tert-butylated hydroquinone and pyrocatechol also in the course of inhibited oxidation of atactic polypropylene200. But these quinoic compounds are formed also in the direct oxidation by oxygen in trichlorobenzene at temperatures above 100 °C200, 201. ... 

The last of the butyl isomers, the tert-butyl compound, was made from a much more obvious starting material. This is the commercially available tert-butyl hydroquinone. It was methylated in... 

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