Cresols ortho- meta

Dow Chemical. 1978. Acute toxicological properties and industrial handlinghazards of cresol (ortho, meta, para isomers). Unpublished data submitted toEPA/OTS. Fiche no. OTS206146. 

Toluene is oxidized to cresols (ortho meta para ratio = 5 1 4) and not to the benzyl derivatives, despite the low dissociation energy of the benzylic C—H bond. p-Xylene undergoes oxidation to 2,5-dimethylphenol. 

Of the three isomeric cresols ortho-, meta-, and para-, only m- cresol can be used as the starting material for introducing three nitro groups, viz. in the 2,4,6-positions. Ortho and p- cresols are able to form stable nitro group systems only when no more than two nitro groups are introduced. Under the conditions of the nitration of m- cresol to its trinitro derivative the o- and p- isomers are oxidized to oxalic acid. 

Blaugas Coal Coal briquettes, hot Coal gas, 2.3 Coal gas, compressed, 2.1, 2.3 Coal tar, crude and solvent Coal tar distillates, flammable, 3, 3.2,3.3 Coal tar naphtha Coal tar oil Coke, hot Creosote Creosote (coal tar or wood tar) Creosote salts Cresols (o-, m-, p-), 6.1, 8 Cresols (ortho- meta- para-), liquid or solid, 6.1 Dead oil Fischer Tropsch gas Fischer-Tropsch gas compressed, 2.2 Iron oxide, spent (obtained fix)m coal gas purification), 4.2 Iron sponge, spent, 4.2 Iron sponge, spent (obtained from coal gas purification), 4.2 Prilled coal tar Synthesis gas Synthesis gas, compressed Water gas Water gas, compressed... 

A compound in which a hydroxyl group is attached directly to the carbon atom of a benzene ring (or of naphthalene or other aromatic ring system) is called a phenol. The simplest phenol is phenol (hydroxybenzene), CeHjOH. The three cresols (ortho, meta, and para) are l-hydroxy-2-methylbenzene, l-hydroxy-3-methylbenzene, and l-hydroxy-4-methyl-benzene, respectively ... 

The oxidation of phenol, ortho/meta cresols and tyrosine with Oj over copper acetate-based catalysts at 298 K is shown in Table 3 [7]. In all the cases, the main product was the ortho hydroxylated diphenol product (and the corresponding orthoquinones). Again, the catalytic efficiency (turnover numbers) of the copper atoms are higher in the encapsulated state compared to that in the "neat" copper acetate. From a linear correlation observed [7] between the concentration of the copper acetate dimers in the molecular sieves (from ESR spectroscopic data) and the conversion of various phenols (Fig. 5), we had postulated [8] that dimeric copper atoms are the active sites in the activation of dioxygen in zeolite catalysts containing encapsulated copper acetate complexes. The high substratespecificity (for mono-... 

Titton Bionetics. 1980a. Sister chromatid exchange assay, Ames assay, mouse lymphoma forward mutation assay, and transformation assay for a sample containing 33-1/3% each ortho-, meta-, and para-cresol. Unpublished data submitted to EPA/OTS. Fiche no. OTS0517528. 

The Lurgi gasifiers used by Sasol operate at "low" temperatures and consequently phenols, and "tars" are "distilled" from the coal at the top of the gasifier, and carried out with the raw gas. On condensation two liquid phases are formed, "tar" and "gas liquor" (water). The "tar acids" (phenol, cresols etc) are dissolved in the "gas liquor" which is fed to the Phenosolvan unit where the acids are recovered by counter current extraction with butyl acetate or diisopropyl ether. The crude tar acids are fractionated to yield phenol, ortho, meta and para cresol and xylenols. The phenol is further refined to produce a high purity, colourless and stable product. Phenol is used mainly in the production of formaldehyde resins while the cresols are used as flotation frothers and in the manufacture of pesticides etc. 

If ortho-, meta- and para-cresol concentrations cannot be differentiated, the total cresol concentration is used. 

Although significant improvements have been made in the synthesis of phenol from benzene, the practical utility of direct radical hydroxylation of substituted arenes remains very low. A mixture of ortho-, meta- and para-substituted phenols is typically formed. Alkyl substituents are subject to radical H-atom abstraction, giving benzyl alcohol, benzaldehyde, and benzoic acid in addition to the mixture of cresols. Hydroxylation of phenylacetic acid leads to decarboxylation and gives benzyl alcohol along with phenolic products [2], A mixture of naphthols is produced in radical oxidations of naphthalene, in addition to diols and hydroxyketones [19]. 

In 1983, Mimoun and co-workers reported that benzene can be oxidized to phenol stoichiometrically with hydrogen peroxide in 56% yield, using peroxo-vana-dium complex 1 (Eq. 2) [20]. Oxidation of toluene gave a mixture of ortho-, meta-and para-cresols with only traces of benzaldehyde. The catalytic version of the reaction was described by Shul pin[21] and Conte [22]. In both cases, conversion of benzene was low (0.3-2%) and catalyst turned over 200 and 25 times, respectively. The reaction is thought to proceed through a radical chain mechanism with an electrophilic oxygen-centered and vanadium-bound radical species [23]. 

Uses Cresol is a mixture of three isomeric forms, namely, ortho-, meta-, and paracresol. Cresol is a colorless, yellowish, brownish yellow, or pinkish liquid with a phenolic odor. It is used as an ore flotation agent and as an intermediate in the manufacture of chemicals, dyes, plastics, and antioxidants. It also is used in the manufacture of dyes, paint removers, plastics, stains, resins, chemical disinfectants, flotations, foundries, wool scours, and insulation enamels. 

Isomerization of arene oxides to phenols proceeds by complex and often multiple pathways660 668 that show a marked dependence on pH. Arene oxides as key intermediates provide the basis for explaining the ortho/meta/para isomer ratios observed in enzymatic hydroxylations.655a,b For example, the absence of m-cresol in the metabolites of toluene can be attributed to the fact that none of the three possible isomers of toluene oxide rearranges to this product. 

Structural Isomers. Chromatograms illustrating the separation of ortho, meta and para isomers of cresol (22) and and xylene ( O)on RP columns are shown in Figures 4 and 5. They enable a comparison of the chromatographic properties and selectivities due to <. - and -CD complexation between positional isomers of the above compounds.Similar behaviour was observed for ortho,meta and para isomers of fluoronitrobenzene, chloronitrobenzene, iodoni-trobenzene, nitrophenol, nitroaniline, dinitrobenzene (22), nitrocinnamic acid (22) some mandelic acid derivatives (19,21,34) and ethyltoluene (28). Both [Pg.225]

Figure 9. Trace A The 2H NMR spectrum from a solution of (N-MeTTP)FeuCl in CD2Cl2/CD3OD (4 1, vol/vol) at -90 °C. Trace B The NMR spectrum from the same solution after the addition of five equivalents of NaOCD3 at —90 °C. Trace B The 2H NMR spectrum from a similar solution as that in trace B prepared from the deuterated complex (N-CD3 d8-TTP)FenCl. Trace C The 1H NMR spectrum of a solution of (N-MeTTP)FeIICl and five equivalents of sodium p-cresolate at—60°C in toluene-d8/methanol-d4 (9 1, vol/vol). Trace C The upfield region of trace C. Resonance assignments Me, the N-methyl protons pyrr, the pyrrole protons o, the ortho protons of the p-tolyl substituents L0, Lm, Lp, the ortho, meta, and para resonances of the axial cresolato ligand. (Reproduced from reference 46. Copyright 1992 American Chemical Society.)...

Let us start with the three isomeric C-monomethylated species (the toluidines or methyl-benzenamines) and accept the recent experimental measurements and analysis17. This source points out the contradictory and incomplete measurements for these species and uses the expression in disarray to describe the literature. From thermoneutral equation 2, we would predict enthalpies of formation of —12, —5 and 55 kJ mol-1 for all three solid, liquid and gaseous toluidines, in reasonable agreement with the experimental values. We note that the o-isomer is slightly more stable than its m- and p-isomers. In comparison, the spread of enthalpy of formation values for the isoelectronic and isosteric xylenes is but 1 kJ mol 1 and for the so-related methylphenols3 (cresols) is but 7 kJ mol 1. As an additional check for thermochemical accuracy, consider the formal methylation reaction 4. For Ar = Ph, the enthalpies of reaction are —36.6 (lq) and —32.2 (g) kJ mol 1. For Ar = C6H4NH2, the ortho, meta and para gas-phase enthalpies of reaction are the... 

The simplest member of the group, phenol, has no isomer, whereas cresols exist in three isomers namely ortho, meta, and para. Xylenols have six different isomers. Some... 

Separation of cresols into pure isomers as ortho-, meta- and para has been discussed in details in a subsequent chapter. While separating xylenols somewhat similar procedure is adopted making use of boiling points differences, and for those isomers with almost identical boiling points using their differences in melting points (solidification points) (see Table 1.2). 

The photochemical destruction of ortho, meta and para-nitrophenols induced by ultra-violet light illumination of aqueous slurries of titanium dioxide has been monitored by electronic absorption spectroscopy the products are said to have been identified as dihydroxynitrobenzene isomers by coupled gas chromatography-mass spectrometry although no details are supplied. Nitrophenols have also been identified in the fog shrouding the University of Bayreuth. They are presumed to be the products of photochemical nitration and the possible precursors (phenol, cresol and nitrate) were also detected. 

Another excellent antiwear compound is tricresyl phosphate (TCP). These compounds are used as a high-temperature antiwear and extreme pressure additive. Tricresyl phosphate is an organophosphate made from cresol and phosphorus oxychloride (shown in Figure 7.5). These compounds come in the ortho-, meta-, and para-cresyl phosphates. They are also used as gasoline additives [4],... 

Cresols o-,m-,p-,), CHjCsH OH, are alcohol hydrocarbon derivatives. They are colorless to yellowish or pinkish liquids. They are found in the ortho, meta, and... 

EPA Priority Pollutant, Acute Toxic Waste, RCRA Waste Number U052 DOT Label Corrosive Material, Poison B Formula CvHgO MW 108.15 CAS [1319-77-3], [95-48-7], [108-39-4], and [106-44-5] for cresol and its ortho- meta-, and j>ara-isomers, respectively Structure ... 

CD-containing mobile phases in HPLC have been successfully used for the separation of various isomers such as structural isomers, diastereomers and enantiomers. For example, ortho, meta, para isomers of cresol, xylene and aU six isomers of nitrocinnamic acid were separated on the Lichrosorb RP-C18 column with jS-CD solution as mobile phase [41]. Similar results were also obtained for ortho, meta and para isomers of nitrophenol, nitroaniline, fluoronitrobenzene. 

Cresol kre- s61 [ISV, irreg. fi. cresote] (ca. 1869) (hydroxytoluene, methylphenol) n. H3CC6H4OH. An important family of coal-tar derivatives, occurring in ortho, meta, and para isomers, and used in the production of phenol-formaldehyde resins and tricresyl phosphate, an important plasticizer for PVC. Three cresols are possible, namely (a) o-cresol, mp 30°C bp, 19rC (b) m-cresol, mp 4°C bp, 205°C (c) p-cresol, mp 36°C bp, 201°C, and these are found together in the crude cresylic acid from coal tar. The main use of the cresols is in the manufacture of cresol-formaldehyde resins, and cresylic acid, rich in the meta isomer, is usually chosen for this purpose. 

Armstrong et al. [110) studied 19 sets, with two to five compounds in each set, of structural isomers (e.g., cresols and xylenes to methylindoles and prostaglandins) on a ) -cyclodextrin colunm (X = 254 nm or 280 nm). Good peak shapes and resolution were obtained for all sets using mobile phases ranging from 30/70 methanol/water (for cresols) to 90/10 methanol/water (for vitamin D2). It was noted that retention for disubstituted benzenes (e.g., the hydroxy/methyl, dimethyl, nitto/hydroxy, nitro/amine and amine/carboxy substituent pairs) usually decreased in the order para > ortho > meta on the ) -cyclodextrin column. 

Many disubstituted compounds have common names. Examples include the xylenes, cresols, and tolui dines, all of which can be ortho, meta, or para isomers. 

Cresol mixture of ortho, meta para 23 56 2 Test failed softened cracking Barex 210 BP Chemicals Specimen 6 oz bottles, capped, per method PT-60, 50% Relative Humidity... 

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