Cresol-hydrogen mixtures

S g of ethyl glycinate hydrochloride were dissolved in 400 cc of ethanol and 33.5 g of salicylic aldehyde were added. It is refluxed for half an hour and cooled. 38 cc of triethylamlne and 25 g of Raney nickel are then added whereafter hydrogenation is carried out at room temperature and under atmospheric pressure. After hydrogen adsorption was complete, the mixture was filtered and the alcohol evaporated off. The residue was taken up with acidified water, extracted with ether to eliminate part of the by-products, consisting mainly of o-cresol, then made alkaline with ammonia and extracted with ethyl acetate. The solvent was removed in vacuo and the residue crystallized from ether/petroleum ether. 36.7 g of o-hydroxybenzyl-aminoacetlc acid ethyl ester melting at 47°C are obtained. 

The kinetics of alkylation by triphenylmethyl compounds have been studied. Hart and Cassis353 found that the alkylation of phenol and o-cresol by triphenylmethyl chloride in o-dichlorobenzene gave non-linear kinetic plots which were, however, rendered linear by presaturation of the reaction mixture with hydrogen chloride, precise third-order kinetics, equation (182)... 

Radon forms a series of clathrate compounds (inclusion compounds) similar to those of argon, krypton, and xenon. These can be prepared by mixing trace amounts of radon with macro amounts of host substances and allowing the mixtures to crystallize. No chemical bonds are formed the radon is merely trapped in the lattice of surrounding atoms it therefore escapes when the host crystal melts or dissolves. Compounds prepared in this manner include radon hydrate, Rn 6H20 (Nikitin, 1936) radon-phenol clathrate, Rn 3C H 0H (Nikitin and Kovalskaya, 1952) radon-p-chlorophenol clathrate, Rn 3p-ClC H 0H (Nikitin and Ioffe, 1952) and radon-p-cresol clathrate, Rn bp-CH C H OH (Trofimov and Kazankin, 1966). Radon has also been reported to co-crystallize with sulfur dioxide, carbon dioxide, hydrogen chloride, and hydrogen sulfide (Nikitin, 1939). 

Pott-Broche A coal liquifaction process in which coal is dissolved in a mixture of tetrahy-dronaphthalene and cresols, and then hydrogenated. Invented by A. Pott and H. Broche at IG Farbenindustrie, Germany in 1927 used by the Ruhrol Company in Germany between 1938 and 1944. See also Exxon Donor Solvent. 

The synthetic process starts with the isopropylation of m-cresol to yield thymol. After catalytic hydrogenation a mixture of stereoisomers is obtained from which (+)-menthol is isolated. The process requires much separation and recycling work. In contrast, the semi-synthetic process of Takasago (Scheme 5.5) leads essentially to stereopure (—)-menthol [19]. 

Solvent-Refined Coal Process. In the 1920s the anthracene oil fraction recovered from pyrolysis, or coking, of coal was utilized to extract 35—40% of bituminous coals at low pressures for the purpose of manufacturing low cost newspaper inks (113). Tetralin was found to have higher solvent power for coals, and the I. G. Farben Pott-Broche process (114) was developed, wherein a mixture of cresol and tetralin was used to dissolve ca 75% of brown coals at 13.8 MPa (2000 psi) and 427°C. The extract was filtered, and the filtrate vacuum distilled. The overhead was distilled a second time at atmospheric pressure to separate solvent, which was recycled to extraction, and a heavier liquid, which was sent to hydrogenation. The bottoms product from vacuum distillation, or solvent-extracted coal, was carbonized to produce electrode carbon. Filter cake from the filters was coked in rotary kilns for tar and oil recovery. A variety of liquid products were obtained from the solvent extraction-hydrogenation system (113). A similar process was employed in Japan during Wodd War II to produce electrode coke, asphalt (qv), and carbonized fuel briquettes (115). 

Another example of the use of deoxidation of oxygen-containing compounds for their structural analysis was given by Wi jnands et al.68, who investigated the structure of novolaks, prepared by polycondensation of formaldehyde with phenol, />-cresol and w-cresol. The novolaks were transformed into saturated hydrocarbon mixtures by direct hydrogenation. Ultimate analysis of the hydrocarbons confirmed the linear structure of the novolaks ... 

A paste oil of the estimated composition was made up and used in hydrogenation. The total salable monophenols (b.p., 180°-205°C.) yield from this was found to be 8.5%, and a stabilized lignin tar yield from the second hydrogenator was 19% of the net organic of the lignin. In addition to the yield data, we fractionally distilled the combined monophenol cuts from the continuous runs. The m->p-cresol peak from the gas chromatograph was analyzed by IR spectroscopy and found to be 45% w-cresol and 55% p-cresol, which meant that no pure p-cresol could be obtained by fractional crystallization of the meta, para mixture. From the fractional distillation we found we could obtain most of the monophenols indicated in the gas chromatographic analysis. 

Aryl halides of many different types, including simple unsubstituted halides, may be conveniently converted into phenols by an indirect route involving the preparation of an arylboronic acid and its subsequent oxidation with hydrogen peroxide. The arylboronic acid (3) is normally prepared by reaction of the corresponding arylmagnesium halide with a borate ester (typically tributyl borate) at between —60 and — 80 °C, to yield the dialkyl boronate ester (2) which is then hydrolysed to the arylboronic acid (3). The latter may be isolated, purified and then oxidised with hydrogen peroxide as described in the preparation of m-cresol (Expt 6.101). Alternatively the crude reaction mixture from the preparation of (3) may be treated directly with hydrogen peroxide.36... 

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]. 

Bis[2-hydroxy-5-methylphenyl] Tellurium Dichloride 1 In a 250 m/, two-necked flask fitted with a reflux condenser and a nitrogen inlet are placed 5.0 g (18 mmol) of tellurium tetrachloride, 4g (37 mmol) of 1-hydroxy-4-methylhenzenc, and 100 m/ of carbon tetrachloride. The mixture is heated to reflux under nitrogen until evolution of hydrogen chloride ceases (100 h). The mixture is then allowed to cool, the precipitate is collected and washed thoroughly with carbon tetrachloride to remove excess cresol followed by benzene to remove unrcacted tellurium tetrachloride. The residue is recrystallized from methanol yield 2.8 g (36%) m.p. 206-212°. 

Ultrasonic interferometry has been used to study ternary mixtures of dimethylsulphoxide, phenol and o-cresol in carbon tetrachloride. The variation of adiabatic compressibility and intermolecular free length with the concentration suggested the occurrence of complex formation by intermolecular hydrogen bonding, which was confirmed from IR spectra [90]. 

P4-22g Alkylated cyclohexanols are important intermediates in the fragrance and perfume industry [Jnd. Eng. Chem. Res., 28, 693 (1989)]. Recent work has focused on gas-phase catalyzed hydrogenation of o-cresol to 2-methylcyclo-hexanone, which is then hydrogenated to 2-methylcyclohexanol, In this problem we focus on only the first step in the reaction (Figure P4-22). The reaction on a nickel-silica catalyst was found to be zero-order in o-cresol and first-order in hydrogen with a specific reaction rate at 170°C of 1.74 mol of o-cresol/(kg cat - min - atm). The reaction mixture enters the packed-bed reactor at a total pressure of 5 atm. The molar feed consists of 67% Hj and 33% o-creso at a total molar rate of 40 mol/min. 

Pure cresol is colorless, yellowish, brownish-yellow, or pinkish liquid. o-Cresol, m-cresol, and p-cresol are the three structural isomers of cresol. The names of the three compounds indicate which of the hydrogens on the benzene ring portion of the molecule have been replaced. They are obtained from coal tar or petroleum. Because the boiling points of these three compounds are nearly the same, a separation of a mixture of the three into its pure components is impractical. 

Derivation (1) A mixture of three isomeric (o-, m-, and p-) cyclic secondary alcohols made by the hydrogenation of cresol, (2) catalytic oxidation of methylcyclohexane. 

Addition of propylene to m-cresol produces thymol. Hydrogenation of thymol gives a mixture of menthol isomers. Treatment of any one of the eight isomers with the same copper chromite catalyst that is used for thymol hydrogenation causes racemization to the same equilibrium mixture of isomers. This fact is used to good effect in the process. The hydrogenation product is optically inactive, being composed of equal amounts of d- and L-isomers of each of the four conformational isomers. The balance between these is 62-64% menthol, 18-20% neomenthol, 10-12% isomenthol and 1-2% neoisomenthol. Since these are pairs of diastereomers, their physical properties differ. Thus,... 

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