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Home Butyl Cellosolve

2-Butoxyethanol

2-Butoxyethanol is an organic solvent with the formula BuOC2H4OH (Bu = CH3CH2CH2CH2). It is a colorless liquid with a sweet, ether-like odour. It is a butyl ether of ethylene glycol. It is a relatively nonvolatile, inexpensive solvent with modest surfactant properties.

Production

2-Butoxyethanol is produced by monoethoxylation of butanol:

C2H4O + BuOH → BuOC2H4OH

In 2006, the total European production of all butyl glycol ethers amounted to 181 kilotons per annum (kt/a), approximately 50% (90 kt/a) of which was 2-butoxyethanol. World production is estimated to be 200 to 500 kt/a, of which 75% is for paints and coatings.

Uses

2-Butoxyethanol is a solvent in paints and surface coatings, as well as cleaning products and inks. Other products that contain 2-butoxyethanol include acrylic resin formulations, asphalt release agents, firefighting foam, leather protectors, oil spill dispersants, degreaser applications, and photographic strip solutions. Other products containing 2-butoxyethanol as a primary ingredient include some whiteboard cleaners, liquid soaps, cosmetics, dry cleaning solutions, lacquers, varnishes, herbicides, and latex paints.

2-Butoxyethanol is frequently found in popular cleaning products. It provides cleaning power and the characteristic odor of Windex and other glass cleaners. It is the main ingredient of many home, commercial and industrial cleaning solutions.

Safety

Butoxyethanol has an LD50 of 2.5g/kg in rats. Laboratory tests by the United States National Toxicology Program have shown that sustained inhalation of high concentrations (100 - 500 ppm) of 2-butoxyethanol can cause adrenal tumors in animals. American Conference of Governmental Industrial Hygienists (ACGIH) reports that 2-butoxyethanol is carcinogenic in animals. OSHA does not regulate 2-butoxyethanol as a carcinogen.

Human exposure

Moderate respiratory exposure to 2-butoxyethanol often results in irritation of mucous membranes of the eyes, nose and throat. Heavy exposure via respiratory, dermal or oral routes can lead to hypotension, metabolic acidosis, hemolysis, pulmonary edema and coma. The current ACGIH threshold limit value (TLV) for worker exposure is 20 ppm in the industrial atmosphere, which is well above the odor threshold of 0.4 ppm. Blood or urine concentrations of 2-butoxyethanol or its major toxic metabolite, 2-butoxyacetic acid, may be measured using chromatographic techniques to monitor worker exposure or to confirm a diagnosis of poisoning in hospitalized patients. A biological exposure index of 200 mg 2-butoxyacetic acid per g creatinine has been established in an end-of-shift urine specimen for exposed U.S. employees.

U.S. Employers are required to inform employees when they are working with this substance.

Butoxyethanol is listed in the U.S. state of California as a hazardous substance, though it was removed from the U.S. Environmental Protection Agency‎'s list of hazardous air pollutants in 1994.

2-Butoxyethanol has come under scrutiny in Canada, and Environment and Health Canada recommended that it be added to Schedule 1 of the Canadian Environmental Protection Act (CEPA). The use of some common household cleaning products containing 2-butoxyethanol could expose people to levels 12 times greater than California's one-hour guideline, especially when indoor use is considered. These products are not required to list it on the label when diluted to a certain point. The safety of the products as normally used is defended by the American Chemistry Council and the Soap and Detergent Association, industry trade groups.

Environment

2-Butoxyethanol usually decomposes in the presence of air within a few days and has not been identified as a major environmental contaminant. It is not known to bioaccumulate.