Uses of Cresylic Acid

Cresylic acid is mainly used as degreasing agent and as a disinfectant of a stabilized emulsion in a soap solution. Cresols are used as flotation agents and as wire enamel solvents. Tricresyl phosphates are produced from a mixture of cresols and phosphorous oxychloride. The esters are plasticizers for vinyl chloride polymers. They are also gasoline additives for reducing carbon deposits in the combustion chamber. 

Solar Energy, Pergamon Press, Oxford, England, 1979. p. 9. 

Zimmerman, W. H., Rosynek, M. P, and Withers, H. P, Texas A M Univ. (TAMU), Proc. 8th Indirect Liquefaction Contractors, Review Meeting, Pittsburgh, 1988. 

Rofer-Depoorter, C. K., Water Gas Shift from Fischer Tropsch, in Catalytic Conversions of Synthesis Gas and Alcohols to Chemicals, edited hy R. G. Herman, Plenum, New York, 1984. 

The Fischer Tropsch Synthesis, in Catalysis Science and Technology, edited hy J. R. Anderson and M. Boudart, Springer Verlag, 1981. 

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Caustic soda is commonly used as the catalyst for the manufacture of resols for mechanical and decorative laminates. However, it is not used in electrical laminates because it adversely affects the electrical insulation properties. For electrical-grade resols ammonia is the usual catalyst, and the resins are usually dissolved in industrial methylated spirits. The use of cresylic acid (m-cresol content 50-55%) in place of phenol yields laminating resins of better electrical properties. 

For uses see cresylic acids. U.S. production of cresylic acid and mixed cresols 1978 65 000 tonnes. 

At other refineries, only two continuous stills in series are used, but these are of 80—100 plate efficiency and yield pure grades of phenol and 0-cresol and a base mixture of cresols, xylenols, and higher boiling tar acids. The latter are fractionated batchwise to various saleable grades of cresylic acids. 

Solvent extraction has become the most widely used method of refining lubricating oils. Selective solvents which extract the less desirable constituents include phenol, furfural, dichloroethyl ether, mixtures of cresylic acid and propane, and liquid sulfur dioxide. Liquid propane precipitates asphaltic constituents and wax and retains the more desirable oil components in solution. Dewaxing may also be accomplished by other solvents such as mixtures of benzene and methyl ethyl ketone. 

The acidification requited to liberate H2S was used to free the supersaturated "sprung oils and acids". These are mainly made up of cresylic acids and there was an attempt to find a market for them. The low solubility of the acids allows sufficient precipitation, if the initial spent caustic is concentrated enough in them. This use is no longer profitable due to the low cost of synthetic phenols. 

The three isomeric cresols (methylphenols) (II) are the main constituents, together with other phenols, of cresylic acid. Cresylic acid is obtained from coal tar distillates and from cracked petroleum naphtha. Cresylic acid has a variable composition according to source and method of preparation. For the preparation of resins, it is preferable to use cresylic acid with a high content of w-cresol (which has three reactive positions see Section 12.4.1). The boiling points of 0-, m-, and p-cresols are 191.0,202.2 and 201.9 C respectively. Thus whilst o-cresol... 

Where either of these is not available, it is recommended that a mixture of 35, 40 and 25 per cent of o-, w- and -cresols respectively should be used, as this mixture has been found to agree closely with the quality of cresylic acid usually employed in soap manufacture. The standard solution is prepared by dissolving TO g of the cresols in 10 ml of N sodium hydroxide and diluting to 1 litre. When phenol is the ingredient 1 g of phenol is substituted for the 1 g of cresol mentioned above. 

The cresols occur in cresylic acid, a mixture of the three cresols together with some xylenols and neutral oils, obtained from coal tar distillates. Only the /n-cresol has the three reactive positions necessary to give cross-linked resins and so this is normally the desired material. The o-isomer is easily removed by distillation but separation of the close-boiling m- and p-isomers is difficult and so mixtures of these two isomers are used in practice. 

Strong alkaline solutions are used to extract cresylic acid. The aqueous layer contains, in addition to sodium phenate and cresylate, a small amount of sodium naphthenates and sodium mercaptides. The reaction between cresols and sodium hydroxide gives sodium cresylate. 

Organophosphate Ester Hydraulic Fluids. Organophosphate esters are made by condensing an alcohol (aryl or alkyl) with phosphorus oxychloride in the presence of a metal catalyst (Muir 1984) to produce trialkyl, tri(alkyl/aryl), or triaryl phosphates. For the aryl phosphates, phenol or mixtures of alkylated phenols (e.g., isobutylated phenol, a mixture of several /-butylphenols) are used as the starting alcohols to produce potentially very complex mixtures of organophosphate esters. Some phosphate esters (e.g., tricresyl and trixylyl phosphates) are made from phenolic mixtures such as cresylic acid, which is a complex mixture of many phenolic compounds. The composition of these phenols varies with the source of the cresylic acid, as does the resultant phosphate ester. The phosphate esters manufactured from alkylated phenylated phenols are expected to have less batch-to-batch variations than the cresylic acid derived phosphate esters. The differences in physical properties between different manufacturers of the same phosphate ester are expected to be larger than batch-to-batch variations within one manufacturer. 

Spent caustic solutions from petroleum refining. Petrochemical refineries use caustics to remove acidic compounds such as mercaptans from liquid petroleum streams to reduce produced odor and corrosivity as well as to meet product sulfur specifications. Spent liquid treating caustics from petroleum refineries are excluded from the definition of solid waste if they are used as a feedstock in the manufacture of napthenic and cresylic acid products. U.S. EPA believes that spent caustic, when used in this manner, is a valuable commercial feedstock in the production of these particular products, and is therefore eligible for exclusion. 

Flotation was carried out at an alkaline pH, controlled by lime. A xanthate collector with cyclic alcohol further (pine oil, cresylic acid) was shown to be the most effective. The use of small quantities of a dithiophosphate-type collector, together with xanthate was beneficial. 

Agents used to forin a froth. are pine oil, cresylic acid and the branched chain alcohols sold by duPont as B series or a mixture of these, alcohols with fuel, or pine oil, sold by the American Cyanamid Co as "AC series"... 

The alcoholysis of sulfites such as dimethyl sulfite offers a convenient method for the preparation of high-boiling dialkyl sulfites [33]. Earlier, Voos and Blanke [8a] reported that dimethyl sulfite is converted to diethyl sulfite in 44 % yield. The reaction was shown to be acid-catalyzed and failed when barium carbonate was present. However, a patent refers to the use of lithium hydride in the transalcoholysis of 2,2-(4,4 -dihydroxyphenyl)propane with diphenyl sulfite or di-o-cresyl sulfite [32]. Recently Mehrotra and Mathur [34] reported that the alcoholysis reaction proceeds in the absence of catalysts. Their results are summarized in Eqs. (21)—(23) and Table VII. Tertiary butanol did not... 

Solvents used in commercial operations at the present time are furfural, phenol, cresylic acid, Chlorex, nitrobenzene, and sulfur dioxide. The Duosol process utilizes a solvent called Selecto which is a mixture of phenol and cresylic acid. The propane used in the Duosol process precipitates the asphalt (18). 

Synthetic resins, such as phenolic and cresylic resins (see PHENOLIC RESINS), are the most commonly used friction material binders, and are usually modified with drying oils, elastomer, cardanol [37330-39-5], an epoxy, phosphorus- or boron-based compounds, or even combinations of two. They are prepared by the addition of the appropriate phenol and formaldehyde [50-00-0] in the presence of an acidic or basic catalyst. Polymerization takes place at elevated temperatures. Other resin systems are based on elastomers (see Elastomers, synthetic), drying oils, or combinations of the above or other polymers. 

Frothers are chemicals whose molecules contain both a polar and a nonpolar group. The purpose of a froth is to carry mineral-laden bubbles lor a period of lime until the froth can be removed from the flotation machine for recovery of ils mineral content. Typical frothing chemicals are alcohols, cresylic acids, eucalyptus oils, camphor oils, and pine oils, all of which are slightly soluble in water. Soluble frolhers in common use include alkyl ethers and phenyl ethers of propylene and polypropylene glycols. 

Emulsion flotation is analogous to carrier flotation. Here, small-sized particles become attached to the surfaces of oil droplets (the carrier droplets). The carrier droplets attach to the air bubbles and the combined aggregates of small desired particles, carrier droplets, and air bubbles float to form the froth. An example is the emulsion flotation of submicrometre-sized diamond particles with isooctane. Emulsion flotation has also been applied to the flotation of minerals that are not readily wetted by water, such as graphite, sulfur, molybdenite, and coal [623]. Some oils used in emulsion flotation include mixed cresols (cresylic acid), pine oil, aliphatic alcohols, kerosene, fuel oil, and gas oil [623], A related use of a second, immiscible liquid to aid in particle separation is in agglomeration flocculation (see Section 5.6.4). 

The structures of the lignins are amenable to conversion to several classes of substituted phenols by thermochemical and thermal degradation methods. The displacement of pyroligneous tars by coal tars eliminated much of the demand that existed for the lignin-based products. Creosote oil or cresylic acid, a mixture of o-, m-, and p-cresols, is now manufactured mainly from coal tars, while only small amounts of cresols are made from wood tars. The use of wood tars and other biomass-derived tars as substitutes for a major portion of the phenol and formaldehyde in phenol-formaldehyde resins could reverse this trend (Himmelblau, 1995). The key to this process seems to be that the... 

The mixture of cresols obtained from coal tar is called cresylic acid, an important technical product used as a disinfectant and in the manufacture of resins and tricresyl phosphate. Cresols are useful as raw materials for various chemical products, disinfectants, and synthetic resins. The isomer o-cresol is a starting material for the herbicides 4,6-dinitro-o-cresol and 2-methyl-4-chlorophenoxyacetic acid. The isomers w-cresol and p-cresol are used in phenol-formaldehyde resins and are converted to tricresyl phosphate (a plasticizer and gasoline additive) and to di-t-butyl cresols (antioxidants called BHT). 

Contamination of water by phenol or substituted phenols is very often due to industrial activity, because these are commercially very important chemicals. Phenol, cresylic acids, and cresols are used for making phenol-formaldehyde resins and tricesyl phosphates. Phenol, alkylphenol, and polyphenols are important raw materials for a wide variety of organic compounds, dyes, pharmaceuticals, plastizers, antioxidants, etc. Phenols are also present in effluents from coke ovens, blast furnaces, and shale oil processing [1]. 

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