Tert-butyl-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. 

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. 

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

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... 

Ermer. O. Robke, C. Crystal structure of 2,5-di-tert-butyl-hydroquinone Polar stacking of nonpolar H-bridged layers with trigonal symmetry. Angew. Chem.. Int. Ed. Engl. 1994. 33 (17). 1755-1757. 

PVM polyvinyl methyl ether TBHQ tert-butyl hydroquinone... 

The above explanations show two potential reasons for the use of plasticizers the decrease of processing temperature for either the matrix polymer or for PANI or for its derivative. Simple substances such as hydroquinone, resorcinol, tert-butyl hydroquinone, 4-hexyl resorcinol, and bisphenol-A have been used as plasticizers in conjunction with polymethylmethacrylate as the matrix polymer. In addition to improved processability, plasticizers have been helpful in organization of polymer chains (lydrogen bonding and phenyl stacking), which results in better charge transfer between the PANI chains. ... 

As redox sensing is one of the ways to activate the Nrf2/Keapl pathway, reactive oxygen species or H2O2, but also electrophilic compounds such as tert-butyl-hydroquinone or oltipraz and numerous natural compounds present in fruits or vegetables such as suUbraphane (Kensler et al. 2013), curcumin, resveratrol, pteros-tilbene (Ramkumar et al. 2013) are known to induce the transcription of Nrf2 target... 

In order to avoid the oxidation of the compounds, several antioxidants can be added as diethyldithiocarbamate [52,79,82], tert-butyl-hydroquinone (TBHQ), [80,83,84] or butylated-hydroxy-toluene (BHT) [81]. Furthermore, internal standards are usually used, such as morin [52,80], luteolin [80], isorhanmetin, [79,82] or kaempferol [79] depending on the phenolic compounds analyzed to monitor losses during sample preparation. 

TBHQ = tert-butyl hydroquinone, 200 ppm hydrogenated oils (%18 3). 

The most effective of the oxidation inhibitors studied are inhibitor 22-46 - 2,2 -methylene-bis-(4-methyl-6-tert-butyl)phenol, santovar "0" - 2,5-di-tert-butyl-hydroquinone, diphenylamine, p-hydroxyneozone, etc. These inhibitors, in conjunction with polyamide, considerably lengthen the induction period and reduce the gas evolution in the oxidation of polyformaldehyde. 

Fig. 79. Effectiveness of the action of inhibitors phenol derivatives, introduced into the polymer (with an addition of 2% polyamide) in a 0.5% concentration. T = 200°C PO2 = 200 mm Hg. 1) Polymer without additives 2) santo-var 0 (2,5-di-tert-butyl-hydroquinone) 3) stable polymer 4) inhibitor 22-46 [2,2 -methylene-bis-(4-tert-butyl-6 - m ethyl) -p henol ].

Additives used in final products Fillers carbon black, montmorillonite, multiwalled carbon nanotubes, silica Plasticizers hydroquinone, resorcinol, tert-butyl hydroquinone, 4-hexyl resorcinol, bisphenol-A, sulfonic acids, phosphonic acids (phenyl phosphonic acid), and aliphatic dIesters of phosphoric acid (diphenyl, dioctyl and dibutyl) UV absorber Tinuvin 213 ... 

Santovar A, (2,5-Di-tert-amyl-hydroquinone Santovar O, (2,3-Di-tert-butyl hydroquinone) Santowhite crystals, (4,4 -Thio-bis-(6-tert-butyl-m-cresol and SCI2)... 

Tert-butyl hydroxyanisole (BHA), tert-butyl hydroxytoluene (BHT), tert-butyl hydroquinone (TBHQ) and propyl gallate (PG) are the most common synthetic phenolic... 

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