Cresol crystallization

O-Cresol- colorless or yellowish liquid M-Cresol- crystals or liquid becoming dark with age and exposure to air and light... 

MCPA, l-methyl-A-chlorophenoxyacetic acid, Methoxone, CgH ClOj. Made by chlorination of o-cresol followed by reaction with chloroethanoic acid. While crystals, m.p. 118-119 C. As usually obtained, crude MCPA contains both 4- (60%) and 6- (40%) chloro-isomers, and is a light brown solid. Selective weedkiller. 

Dissolve a few crystals of phenol in water and add ferric chloride solution a violet coloration is produced. Repeat, using i 2 drops of m-cresol shaken up with about i ml. of water a violet coloration is again produced. Catechol (in dilute solution) gives a green coloration. 

Solubility and Solvent Resistance. The majority of polycarbonates are prepared in methylene chloride solution. Chloroform, i7j -l,2-dichloroethylene, yy -tetrachloroethane, and methylene chloride are the preferred solvents for polycarbonates. The polymer is soluble in chlorobenzene or o-dichlorobenzene when warm, but crystallization may occur at lower temperatures. Methylene chloride is most commonly used because of the high solubiUty of the polymer (350 g/L at 25°C), and because this solvent has low flammabiUty and toxicity. Nonhalogenated solvents include tetrahydrofuran, dioxane, pyridine, and cresols. Hydrocarbons (qv) and aUphatic alcohols, esters (see Esters, organic), or ketones (qv) do not dissolve polycarbonates. Acetone (qv) promotes rapid crystallization of the normally amorphous polymer, and causes catastrophic failure of stressed polycarbonate parts. 

The solubihty of alkylphenols in water falls off precipitously as the number of carbons attached to the ring increases. They are generally soluble in common organic solvents acetone, alcohols, hydrocarbons, toluene. Solubihty in alcohols or heptane follows the generalization that "like dissolves like." The more polar the alkylphenol, the greater its solubihty in alcohols, but not in ahphatic hydrocarbons likewise with cresols and xylenols. The solubihty of an alkylphenol in a hydrocarbon solvent increases as the number of carbon atoms in the alkyl chain increases. High purity para substituted phenols, through Cg, can be obtained by crystallization from heptane. 

Up 1.4575. Purified by dilution with an equal volume of pet ether, then saturated with dry HBr. The ppte was filtered off, washed with small vols of pet ether, then cineole was regenerated by stirring the crystals with H2O. It can also be purified via its o-cresol or resorcinol addition compds. Stored over Na until required. Purified by fractional distn. Insoluble in H2O but soluble in organic solvents. [IR Kome et al. Nippon Kagaku Zasshi [J Chem Soc Japan (Pure Chem Sect)] 80 66 1959 Chem Abstr 603 1961.]... 

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. 

Fig. 134.—Phase diagram for poly-(N,N -sebacoyl piperazine) with each of the diluents m-cresol (A), o-nitrotoluene ( ), and diphenyl ether O crystallization, O liquid-liquid separation). (Flory, Mandelkern, and Hall. )...

In some cases we may benefit from using an external agent to carry out the desired separation through crystallization. Thus, in the case of isomeric and non-isomeric mixtures of close-boiling acidic or basic materials we may use a suitable base or acid to carry out dissociative extractive crystallization, akin to dissociative extraction referred to in Section 4.2.1. For instance, for a mixture of p- and m-cresol or p-cresol and 2,6-xylenol we may use a base like anhydrous piperazine to obtain a precipitate of relatively pure p-cresol salt of piperazine, which can then be filtered and subjected to recovery of piperazine for recycle. Similarly, we may add a substance which forms an adduct with the desired substance. 

A substitution of the methyl group in the para-position (Fig. 36) causes a larger expansion of the unit cell along c. The crystal packing of the resulting structure is still an efficient one, however the p-substituted methyl introduces already some steric hindrance into the structure the shortest distance of the methyl from its surroundings (adjacent phenyl walls ) is 3.56 A as compared to the normal van der Waals methyl — — phenyl distance of about 3.7 A49>. This steric misfit could be responsible for the preferential complexation of host 25 with m-cresol rather than with p-cresol. 

Dimethylol-o-cresol. A. Thirty seven percent formalin solution (16.2g) was added to a solution of o-cresol (lOg) and sodium hydroxide (4g) in 20 ml H20 at 0CC. After standing at room temperature for two days the solution was brought to pH 8.2 by the addition of 10% acetic acid and crystallization of 2,4-dimethylol-o-cresol began. 

The product was recrystallized from chloroform to obtain white needles melting at 93-94°C (Lit (34,35) m.p. 93-94°C). The yield was 67 percent. It is important that very pure o-cresol be used for this preparation use of impure o-cresol impedes crystallization of the product and it remains in solution, slowly forming 2,2 -dihydroxy-3,3 -dihydroxymethyl-1,1 -dimethyldiphenylmethane II, m.p. 153-1554C (Lit m.p. 155°C (34)) in 40 percent yield. 

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). 

Many properties of polyamides are attributable to the formation of hydrogen bonds between the NH and CO groups of neighboring macromolecules. This is evidenced by their solubility in special solvents (sulfuric acid, formic acid, m-cresol), their high melting points (even when made from aliphatic components), and their resistance to hydrolysis. In addition, polyamides with a regular chain structure crystallize very readily. 

Cresol red Crystal Violet Malachite Green Methanil Yellow Thymol Blue Orange IV -2,4-Dinitrophenol -Erythrosin, Na2 salt -Dimethyl Yellow Cl 11020 Bromophenol Blue Congo Red Cl 22120 Methyl Orange Bromocresol Green Alizarin Red S Cl 42750 Methyl Red Cl 13020 -Bromocresol Purple Chlorophenol Red p-Nitrophenol Alizarin Bromothymol Blue Brillant Yellow Phenol Red Neutral Red Cl 50040 -m-NItrophenol -Cresol Red Metacresol Purple Phenolphthalein -Thymolphthalein -P-Naphthyl Violet Alizarin Yellow R 2,4,6-T rinitrotoluene... 

C15H14O2, Mr 226.27, is prepared by esterification of p-cresol with phenylacetic acid. It forms crystals (mp 75—76 °C) with a narcissus odor and a honey note. It is used in blossom compositions with a slight animal note. 

Isophane insulin is a white suspension of rod-shaped crystals approximately 30- Jm long, and free from large aggregates of crystals after being subjected to moderate agitation. It contains either 1.4-1.8% glycerol, 0.15-0.17% meta-cresol, and 0.06-0.07% phenol on a wt/vol basis, or 1.4—1.8% glycerol and 0.20-0.25% phenol (wt/vol), at a pH of 7.1-7.4. It also contains 0.15-0.25% (wt/vol) of sodium phosphate, 0.01-0.04 mg of zinc, and 0.3—0.6 mg of protamine for each USP insulin unit. The insoluble matter in the suspension is crystalline and contains not more than traces of amorphous material. 

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. 

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