Catechol

Description

Catechol is a white crystalline solid. Turnsbrown on contact with light and air. Molecularweight=110.12; Specific gravity (H2O:1)=1.3; Boilingpoint=245.5℃; Freezing/Melting point=104℃. It sublimes readily; Vapor pressure=10 mmHg at 117℃; Flashpoint=127℃; Autoignition temperature=512℃.Explosive Limits in air: LEL=1.4%; UEL-Unknown.Hazard Identification (based on NFPA 704 M RatingSystem): Health 3, Flammability 1, Reactivity 2. Solubilityin water=44%.

Chemical Properties

Catechol also called Pyrocatechol is a white crystalline solid. Turns brown on contact with light and air.

Chemical Properties

Off-white powder

Uses

Catechol is used in photography, in dyeing fur, and as a topical antiseptic.

Uses

In the manufacture of rubber antioxidants and monomer inhibitors to stop radical polymerization; in dyes, as a photographic developer; in formulations for pharmaceuticals, perfumes, inks, and insecticides

Uses

In photography; dyeing fur; as reagent.

Definition

A colourless crystalline PHENOL containing two hydroxyl groups. It is used in photographic developing.

Production Methods

Catechol may be obtained by the fusion of o-phenolsulfonic acid with alkali, by heating chorophenol with a solution of sodium hydroxide at 200°C in an autoclave, or by cleavage of the methyl ether group of guaiacol (obtained from beechwood tar) with hydriodic acid.

Synthesis Reference(s)

The Journal of Organic Chemistry, 45, p. 4275, 1980 DOI: 10.1021/jo01310a003

General Description

Solid; white; odorless. Sinks and mixes with water.

Air & Water Reactions

Turns brown on exposure to air and light, especially when moist. Water soluble. Aqueous solutions soon turn brown on exposure to air and light.

Reactivity Profile

POISONOUS GASES MAY BE PRODUCED WHEN HEATED. Pyrocatechol may form toxic fumes at high temperatures. [USCG, 1999]. Pyrocatechol can react with acid chlorides, acid anhydrides, bases and oxidizing agents. Pyrocatechol reacts violently on contact with concentrated nitric acid. Pyrocatechol acts as a reducing agent .

Hazard

Strong irritant. Toxic by skin absorption. Eye and upper respiratory tract irritant, and der- matitis. Possible carcinogen.

Health Hazard

DUST: Irritating to eyes, nose and throat. If inhaled will cause coughing or difficult breathing. SOLID: Will burn skin and eyes. Harmful if swallowed.

Health Hazard

Acute oral and percutaneous toxicity of pyrocatechol is greater than that of phenol; inhalation toxicity is less than that of phenol. The toxic symptoms include weakness, muscular pain, dark urine, tremor, dyspnea, and convulsions. Large amounts can produce degenerative changes in renal tubules. Large doses can cause death due to respiratory failure. Skin contact can cause eczematous dermatitis.
LD50 value, oral (rats): 260 mg/kg
LD50 value, skin (rabbits): 800 mg/kg.

Fire Hazard

Combustible. POISONOUS GASES MAY BE PRODUCED WHEN HEATED. May form toxic fumes at high temperatures.

Flammability and Explosibility

Non flammable

Safety Profile

Poison by ingestion, subcutaneous, intraperitoneal, intravenous, and parenteral routes. Moderately toxic by skin contact. Experimental reproductive effects. Can cause dermatitis on skin contact. An allergen. Human mutation data reported. Questionable carcinogen. Systemic effects sirmlar to those of phenol. Combustible when exposed to heat or flame; can react vigorously with oxidizing materials. Hypergolic reaction with concentrated nitric acid. To fight fire, use water, CO2, dry chemical. When heated to decomposition it emits acrid smoke and irritating fumes. See also PHENOL.

Potential Exposure

Used as a chemical intermediate; pharmaceutical and veterinary drug; as an antiseptic; in photography; in dyestuff manufacture and application. It is also used in electroplating, in the formulation of specialty inks; in antioxidants; and light stabilizers.

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medical attention. Give large quantities of water and inducevomiting. Do not make an unconscious person vomit.
Note to physician: Treat for methemoglobinemia.Spectrophotometry may be required for precise determination of levels of methemoglobinemia in urine.

Carcinogenicity

Catechol has been extensively studied for its role in carcinogenesis of the rat glandular stomach; it was concluded that pyrocatechol is carcinogenic. When rats and mice were administered 0.8% pyrocatechol in their feed for life, there was an increase in glandular stomach adenocarcinoma in both male and female rats. Pyrocatechol also caused hyperplasia of the glandular stomach in both rats and mice, a mechanism that could cause promotion of carcinogen-initiated cells; no effects on the esophagus or urinary bladder were reported. There were no cutaneous neoplasms when pyrocatechol was applied in dermal studies. Catechol may be classified as a cocarcinogen because it enhanced the number and/or incidence of lesions in the stomach induced by several carcinogenic nitrosamines and cutaneous neoplasms when administered dermally together with several carcinogens.

storage

Color Code—Blue: Health Hazard/Poison: Storein a secure poison location. Prior to working with catecholyou should be trained on its proper handling and storage.Before entering confined space where this chemical may bepresent, check to make sure that an explosive concentrationdoes not exist. Store in tightly closed containers in a cool,well-ventilated area away from strong oxidizers and acids.Use only nonsparking tools and equipment, especially whenopening and closing containers of this chemical. Sources ofignition, such as smoking and open flames, are prohibitedwhere this chemical is used, handled, or stored in a mannerthat could create a potential fire or explosion hazard.

Shipping

UN 2811 Toxic solids, organic, n.o.s., Hazard Class: 6.1; Labels: 6.1-Poisonous materials, Technical Name Required.

Purification Methods

Crystallise catechol from *benzene or toluene and sublime it in vacuo. [Rozo et al. Anal Chem 58 2988 1986, Beilstein 6 IV 5557.]

Incompatibilities

Incompatible with oxidizers (chlorates, nitrates, peroxides, permanganates, perchlorates, chlorine, bromine, fluorine, etc.); contact may cause fires or explosions. Keep away from alkaline materials, strong bases, strong acids, oxoacids, epoxides.