о-крезол

Химические свойства

o-Cresol has a musty, phenolic aftertaste.

Физические свойства

Colorless solid or liquid with a phenolic odor; darkens on exposure to air. An odor threshold concentration of 0.28 ppb_v was reported by Nagata and Takeuchi (1990).

Вхождение

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.

Использование

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.

Определение

ChEBI: A cresol that is phenol substituted by a methyl group at position 2. It is a minor urinary metabolite of toluene.

Методы производства

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.

Общее описание

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.

Реакции воздуха и воды

Sensitive to light and air. Insoluble in water.

Профиль реактивности

o-Cresol is incompatible with oxidizing agents and bases. Mixing o-Cresol with chlorosulfonic acid, nitric acid and oleum in a closed contained caused the temperature and pressure to increase.

Опасность

Questionable carcinogen.

Угроза здоровью

The chemical is rated as a very toxic compound with a probable oral lethal dose in humans of 50-500 mg/kg, or between 1 teaspoon and 1 ounce for a 70 kg (150 lb.) person. It is a strong dermal irritant and frequently causes dermatitis. Serious or fatal poisoning may result if large areas of skin are wet with cresol, o- and the substance is not removed immediately. Ingestion of even a small amount may cause paralysis and coma. It is corrosive to body tissues, with toxicity similar to phenol.

Пожароопасность

Fire may produce irritating or poisonous gases. Runoff from fire control water may give off poisonous gases. o-Cresol may burn but does not ignite readily. Container may explode in heat of fire. Slight explosion and fire hazard in the form of vapor when exposed to heat or flame. When heated to decomposition, o-Cresol emits highly toxic fumes. Reacts violently with nitric acid, oleum, and chlorosulfonic acid. Hazardous polymerization may not occur.

Профиль безопасности

Poison by ingestion, inhalation, subcutaneous, intravenous, and intraperitoneal routes. Moderately toxic by skin contact. A severe eye and skin irritant. Human mutation data reported. Questionable carcinogen with experimental neoplastigenic data. Flammable when exposed to heat, flame, or oxidants. To fight fire, water may be used to blanket fire; foam, fog, mist, dry chemical. See also other cresol entries and PHENOL.

Возможный контакт

Cresol is used as a disinfectant and fumigant; as an ore flotation agent, and as an intermediate in the manufacture of chemicals, dyes, plastics, and antioxidants. A mixture of isomers is generally used; the concentrations of the components are determined by the source of the cresol.

Перевозки

UN2076 Cresols, liquid, Hazard class: 6.1; Labels: 6.1-Poisonous materials, 8-Corrosive material. UN3455 Cresols, solid, Hazard class: 6.1; Labels: 6.1- Poisonous materials, 8-Corrosive material.

Методы очистки

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.]

Несовместимости

Vapors may form explosive mixture with air. Incompatible with strong acids; oxidizers, alkalies, aliphatic amines; amides, chlorosulfonic acid; oleum. Decomposes on heating, producing strong acids and bases, causing fire and explosion hazard. Liquid attacks some plastics and rubber. Attacks many metals.

Утилизация отходов

Wastewaters may be subjected to biological treatment. Concentrations may be further reduced by ozone treatment. High concentration wastes may be destroyed in special waste incinerators.