Hydroquinone from phenol

Kennedy and Stock reported the first use of Oxone for many common oxidation reactions such as formation of benzoic acid from toluene and of benzaldehyde, of ben-zophenone from diphenyhnethane, of frawi-cyclohexanediol Ifom cyclohexene, of acetone from 2-propanol, of hydroquinone from phenol, of e-caprolactone from cyclohexanone, of pyrocatechol from salicylaldehyde, of p-dinitrosobenzene from p-phenylenediamine, of phenylacetic acid from 2-phenethylamine, of dodecylsulfonic acid from dodecyl mercaptan, of diphenyl sulfone from diphenyl sulfide, of triphenylphosphine oxide from triphenylphosphine, of iodoxy benzene from iodobenzene, of benzyl chloride from toluene using NaCl and Oxone and bromination of 2-octene using KBr and Oxone . Thus, they... 

Improvements of already existing oxidation processes are continuously made (in MAA manufacture, with the riser reactor by DuPont, or in oxychlorination, by Montecatini Technologic and ICI). In addition, and still more clearly demonstrating the dynamism of industrial catal5rtic oxidation, completely new catalysts are discovered, especially with the titanium silicalite which permits the synthesis of hydroquinone from phenol, selective epoxidations, oxidations of alcohols to aldehydes, and the manufacture of cyclohexanoneoxime. 

Development of a titanosilicate (TS-1) catalyst for the production of catechol and hydroquinone from phenol... 

The synthesis of chlorarul [118-75-2] (20) has been improved. The old processes starting from phenol or 2,4,6-trichlorophenol have been replaced by new ones involving hydroquinone chlorination. These processes allow the preparation of chlorarul of higher purity, avoiding traces of pentachlorophenol. Different types of chlorination conditions have been disclosed. The reaction can be performed according to the following stoichiometry, operating with chlorine in aqueous acetic acid (86,87), biphasic medium (88), or in the presence of surfactants (89). 

Catechol is produced by coproduction with hydroquinone starting from phenol. Other techniques such as coal extraction remain marginal. The installed capacities (- 25,000 t/yr) are now sufficient to cover the demand. Catechol is mainly used for synthesis in food, pharmaceutical, or agrochemical ingredients. A specific appHcation of / fZ-butylcatechol is as a polymerisation inhibitor. 

In small-scale syntheses, a wide variety of oxidants have been employed in the preparation of quinones from phenols. Of these reagents, chromic acid, ferric ion, and silver oxide show outstanding usefulness in the oxidation of hydroquinones. Thallium (ITT) triduoroacetate converts 4-halo- or 4-/ f2 -butylphenols to l,4-ben2oquinones in high yield (110). For example, 2-bromo-3-methyl-5-/-butyl-l,4-ben2oquinone [25441-20-3] (107) has been made by this route. 

Quinone(s), 631 from phenols. 631 hydroquinones from, 631 reduction of, 631... 

The rare example of synergistic action of a binary mixture of 1-naphthyl-A-phcnylaminc and phenol (1-naphthol, 2-(l,l-dimethylethyl)hydroquinone) on the initiated oxidation of cholesterol esters was evidenced by Vardanyan [34]. The mixture of two antioxidants was proved to terminate more chains than both inhibitors can do separately ( > /[xj). For example, 1-naphtol in a concentration of 5 x 10 5 mol L-1 creates the induction period t=170s, 1 -naphthyl-A-phenylamine in a concentration of 1.0 x 10-4 mol L 1 creates the induction period t = 400s, and together both antioxidants create the induction period r = 770 s (oxidation of ester of pelargonic acid cholesterol at 7= 348 K with AIBN as initiator). Hence, the ratio fs/ZfjXi was found equal to 2.78. The formation of an efficient intermediate inhibitor as a result of interaction of intermediate free radicals formed from phenol and amine was postulated. This inhibitor was proved to be produced by the interaction of oxidation products of phenol and amine. 

FIGURE 4.80 Oxidative mechanisms for the formation of hydroquinone from / -substituted phenols. 

Polymers and resins Water purification, including removal of phenol, chlorophenols, ketones, alcohols, aromatics, aniline, indene, polynuclear aromatics, nitro- and chlor-aromatics, PCB, pesticides, antibiotics, detergents, emulsifiers, wetting agents, kraftmill effluents, dyestuffs recovery and purification of steroids, amino acids and polypeptides separation of fatty adds from water and toluene separation of aromatics from ahphatics separation of hydroquinone from monomers recovery of proteins and enzymes removal of colours from symps ... 

Validation of the model. Validation of the model was performed using data from rat and mouse liver microsome preparations (Schlosser et al. 1993). The assumption that benzene and its metabolites compete for the same enzyme reaction site was supported in part by the observation of a lag time in the benzene-to-hydroquinone reaction as compared to the phenol-to-hydroquinone reaction. This lag could be explained by the fact that benzene is first hydrolyzed to phenol, which is then hydrolyzed to hydroquinone, and if all compounds are substrates for P-450 2E1, the kinetics of this pathway would be slowed compared to those of the direct phenol-to-hydroquinone pathway. The model also adequately predicted phenol depletion and concomitant hydroquinone formation resulting from phenol incubations. 

Problem 19.33 From phenol prepare (a) p-benzoquinone, (b) p-benzoquinone dioxime, (c) quinhydrone (a 1 1 complex of p-benzoquinone and hydroquinone). 4... 

Well-established is the formation of hydroquinone and phenol derivatives 273 from alkynes. This reaction is called the Dotz reaction [78,79]. The reaction of carbene complex 271 to give 273 can be expressed by the general scheme 272. 

Bielicka-Daszkiewicz, K., A. Voelkel, M. Szejner, and J. Osypisk. 2006. Extraction properties of new polymeric sorbents in SPE/GC analysis of phenol and hydroquinone from water samples. Chemosphere 62 890-898. 

In recent years hypervalent iodine compounds have experienced extensive investigations yielding many results of practical synthetic importance. Supported iodi-nanes, i.e. iodoso or iodine(III) reagents, have been prepared by several groups, mainly as the bis-acetoxyiodoso derivatives [15-18] or as the respective dihalogeno compounds [19]. Iodoso reagents are employed in the oxidation of hydroquinones and phenols that have been exploited in the formation of spiroketals from a variety of tyrosines. 

Fleszar and Sobkowiak [120] obtained less than 5% of catechol and hydroquinone from the hydroxylation of benzene and phenol on Hg, Pb, Cu, and Ag cathodes, even in the absence of Fe(II). It appears that the generation of H202 occurs even in electrodes where it may undergo catalytic decomposition if there are small quantities of adsorbable substances in solution. 

Therefore, additional heat aging tests were conducted to investigate the possibility that hydroquinone-derived phenolic groups might function differently from the monohydric phenols and somehow contribute to the high activity of the phenolic-phosphite systems. Two substituted hydro-quinones, two polymeric phenolic phosphites based on those hydro-quinones, and combinations of the hydroquinones with triphenyl phosphite and tris(nonylphenyl) phosphite were evaluated in the oven-aging test again 0.4% DLTDP was included in the formulations. 

The antioxidants BHA and BHT are commonly used as food preservatives. Show how BHA and BHT can be made from phenol and hydroquinone. 

Apart from nitrophenols, 4-nitrocatechol and nitrobenzoquinone have also been detected as nitro derivatives [54,79,100]. They are secondary photoproducts and are thought to originate from the nitration of catechol and hydroquinone, in the latter case followed by the oxidation of nitrohy-droquinone [54,100]. 4-Nitrocatechol might in principle derive from catechol nitration or from 4-nitrophenol hydroxylation. However, the conversion of 4-nitrophenol into 4-nitrocatechol upon nitrate photolysis is rather limited [109] and cannot account for the observed time evolution starting from phenol [54]. 

Data produced in vitro by mouse and rat liver microsomes also indicate species differences in benzene metabolism (Schlosser et al. 1993). Quantitation of metabolites from the microsomal metabolism of benzene indicated that after 45 minutes, mouse liver microsomes from male B6C3Fj mice had converted 20% of the benzene to phenol, 31% to hydroquinone, and 2% to catechol. In contrast, rat liver microsomes from male Fischer 344 rats converted 23% to phenol, 8% to hydroquinone, and 0.5% to catechol. Mouse liver microsomes continued to produce hydroquinone and catechol for 90 minutes, whereas rat liver microsomes had ceased production of these metabolites by 90 minutes. Muconic acid production by mouse liver microsomes was <0.04 and <0.2% from phenol and benzene, respectively, after 90 minutes. 

Legathe et al. (1994) investigated the pharmacokinetics of hydroquinone and phenol in blood and recovery in urine after intraperitoneal administration of 75 mg/kg alone or in combination to B6C3Fj mice. Combined administration resulted in a 2.6-fold increase in the area under the curve (AUC) for blood concentration of hydroquinone, and increased the half-life of hydroquinone from 9 to 15 minutes. The AUC of phenol was increased by a factor of 1.4, and clearance of phenol was decreased from... 

Various oligomeric and polymeric stabilizers containing PC units were synthesised. Oligomers prepared from phosgene and 4,4 -isopropylidenebis(2-re/ r-butylphen-ol), or 2,5-bis(2-hydroxyethyl)hydroquinone, from diphenyl carbonate and 4,4 -isopropylidenebisphenol,4,4 -butylidenebis(6-rcrt-butyl-3-methylphenol), or substituted monohydric and dihydric mononuclear phenols, e.g. l-(3,5-di-tert-butyl-4-hydroxyphenyl)-3,3-bis[(3-terr-butyl-4-hydroxyphenyl)butane] carbonate (155)... 

Extraction of cryptophenois and enok. Phenols insoluble in aqueous alkali, for example 2,4,6-triallylphenol, can be extracted from petroleum ether with Claisen s alkali. Vitamin K, is easily isolated from a 3-5% alfalfa concentrate by shaking an alcoholic suspension of the oil with aqueous sodium hydrosulfite, extracting with petroleum ether, and extracting the Kj hydroquinone from petroleum ether with Claisen s alkali. The yellow extract is diluted with water and Ki hydroquinone OH CHj CH, CHj CH,... 

The equation for the formation of hydroquinone from quinone has been given above- All homologous quinones react in the same way. The hydroquinones are di-acid phenols, which dissqlve in alkalies and show all the properties of phenols. They are not volatile with steam. 

TP and Ag + were found to react with 4-methoxyphenol and 3,5-dimethoxyphenol by 100% electron transfer (equation 2), whereas with TlOH the efficiency of electron transfer is only ca 75%. The ease of oxidation increases considerably in going from the neutral phenols to the phenolates even the weak oxidants Tl(OH)2 and Ag(OH)2 are able to oxidize the phenolates with 100% yield to give the corresponding phenoxyl radicals. In going from phenol to the dihydroxybenzenes the oxidizability increases hydroquinone and resorcinol are oxidized with 100% yield not only by TP but also by the weaker oxidant TlOH . Catechol forms a complex with Tl(II), which has the same structure as thaf produced by reaction of ortfjo-semiquinone radical with Tl or by reaction of ort/io-benzoquinone with XT . The rate constants for reaction of the Tl(II) and Ag(II) species are between 10 -10 M s (see Table 1). 

The best-known noble gas clathrates are hydrates, hydroquinone and phenol clathrates, which have found an increasing number of uses [131]. Clathrates may serve as convenient storage for noble gases. Because of the different affinity hydroquinone clathrate prepared from an equal mixture of krypton and xenon liberates 3 times the amount of Xe than Kr [132]. Clathrates are also of interest for nuclear technology. Radioactive isotopes of argon, xenon and krypton can more easily be handled in the compact form of a solid rather than in gas form [133-136]. 

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