methylphenols

Methylphenols are a large class of aromatic compounds in which a phenol ring bears one or more methyl substituents. The best-known members are the cresols, which have a single methyl group and include o-cresol (2-methylphenol), m-cresol (3-methylphenol), and p-cresol (4-methylphenol). Compounds with two methyl groups on the ring are called xylenols, such as various 2,4- and 3,5-dimethylphenol isomers. The term methylphenols can also refer to other methyl-substituted phenols.

Occurrence and production: Cresols occur naturally in coal tar and wood tar and are produced industrially by distillation and processing of these tars. They are also obtainable by methylation of phenol or by peripheral processes in petrochemical streams. Xylenols are obtained from coal tar or as byproducts of refining, and may be prepared by methylating phenol or cresols followed by separation of isomers.

Properties and uses: Methylphenols are typically colorless to pale yellow liquids with a characteristic phenolic odor. They are relatively volatile, corrosive, and can be toxic to skin, eyes, and respiratory systems. Cresols are used as solvents and as antiseptics or disinfectants; they also serve as chemical precursors in the manufacture of resins, dyes, pesticides, and other industrial chemicals. Xylenols are mainly used as intermediates in resin and dye production and in related chemical syntheses.

Safety and environment: Handling requires protective equipment and appropriate ventilation due to their irritant and toxic nature. They pose risks to aquatic life and can contaminate water if released. Regulation and proper disposal are important in workplaces that handle methylphenols.