o-クレゾール

用途防腐剤、消毒剤

用途水質試験用

用途有機合成原料、溶剤。

天然物の起源Reported in Acacial farnesiana, ylang-ylang oil (probably as p-cresyl acetate), jasmine absolute, orange oil from leaves, the essence from flowers of Lilium candidum, anise seed oil, the essence of Artemisia santolinoflia, and some sea algae. Also reported found in asparagus, peppermint oil, cheddar cheese, provolone cheese, butter, milk, lean fish, boiled egg, smoked pork, rum, Scotch whiskey, red wine, white wine, coffee and mango.Reported found in cinnamon, coffee, Oriental tobacco, rum, sherry, tea, tomato and whiskey.

使用o-Cresol is used as a disinfectant and solvent. Lysol disinfectant is a 50% (v/v) mixed-cresol isomer in a soap emulsion formed on mixing with water. Besides disinfection products at solutions of 1–5%, the cresols are used as degreasing compounds, paintbrush cleaners, and additives in lubricating oils. Cresols were previously widely used for disinfection of poultry houses, but this use was discontinued because of their toxicity; they cause respiratory problems and abdominal edema in young chicks. o-Cresol has been used in synthetic resins, explosives, petroleum, photographic, paint, and agricultural industries.

一般的な説明Colorless or yellow to brown-yellow or pinkish colored liquid with a phenol-like odor. Toxic by ingestion and/or skin absorption. May have a flash point between 100 and 199°F. Causes burns to skin, eyes and mucous membranes. Insoluble in water.

Approximately 60% of o-cresol is obtained from coal-tar and crude oil by using classical techniques such as distillation, stripping, and liquid–liquid extraction. The remaining 40% is obtained synthetically by the alkylation of phenol with methanol. The cresols (cresylic acids) are methyl phenols and generally appear as a mixture of isomers. o-Cresol is a 2-methyl derivative of phenol and is prepared from o-toluic acid or obtained from coal tar or petroleum. Crude cresol is obtained by distilling “gray phenic acid” at a temperature of ≈180–201°C. o-Cresol may be separated from the crude or purified mixture by repeated fractional distillation in vacuo. It can also be prepared synthetically by diazotization of the specific toluidine or by fusion of the corresponding toluenesulfonic acid with sodium hydroxide.

合成方法フェノールとメタノールを金属酸化物（たとえばAl2O3）触媒存在下で反応させる

純化方法It can be freed from m-and p-isomers by repeated fractional distillation, It crystallises from *benzene by addition of pet ether. It has been fractionallly crystallised by partial freezing of its melt. The 3,5-dinitrobenzoate (prepared with 3,5-dinitrobenzoyl chloride in dry pyridine, and recrystallised from EtOH or aqueous Me2CO) has m 138o. [Beilstein 6 IV 1940.]