Ethers of Ethylene Glycol and Derivatives

Abstract

There are currently seven U.S. manufacturers of ethers and other derivatives of ethylene glycol (EG), diethylene glycol (DEG), and higher glycols. Five of them are members of the American Chemistry Council (ACC) Glycol Ethers' Panel. The glycol ethers most commonly encountered industrially are colorless liquids that have mild ethereal odors. Alkyl glycol ethers are manufactured in a closed, continuous process by reacting ethylene oxide with an anhydrous alcohol in the presence of a suitable catalyst. Depending on the molar ratios of the reactants and other process parameters, the product mixtures obtained contain varying amounts of the monoethylene‐, diethylene‐, triethylene‐, and higher glycol ethers. Typically, the products in these mixtures are separated and purified by fractional distillation. The miscibility of most of these ethers with water and with a large number of organic solvents makes them especially useful as solvents in oil–water compositions. Their relatively slow rate of evaporation also makes them useful as solvents and coalescing agents in paints. Other uses include inks, cleaners, chemical intermediates, process solvents, brake fluids, and deicers. The ethers of the higher glycols are used as hydraulic fluids. An estimate of the U.S. production and use of representative ethylene glycol ethers is presented. Production of ethylene glycol ethers (total) in Western Europe amounted to 245 thousand metric tons in 1995. Occupational exposure to glycol ethers occurs dermally and by inhalation. Ingestion is not a concern in industrial exposure, although some cases of intentional ingestion of consumer products containing ethylene glycol ethers have been reported. A number of analytical methods have been published that are suitable for detecting glycol ethers in environmental air samples. Glycol ethers generally have low acute, single‐dose toxicity, and LD 50 values generally range from 1.0 to 4.0 g/kg of body weight. In animals and humans, high‐dose administrations (>350 mg/kg) result in central nervous system depression, although the results from many studies show no specific damage to neural tissues. Other toxicological effects attributable to glycol ethers are associated with metabolism to the corresponding alkoxyacetic acids. In the case of EGME, EGEE, and certain other glycol ether derivatives, significant reproductive, developmental, hematologic, and immunologic effects have been associated with the formation of either methoxyacetic (MAA) or ethoxyacetic acids (EAA). For other glycol ether derivatives substituted with propyl, butyl, or higher homologues, developmental effects secondary to maternal toxicity (without teratogenic effects), as well as hematologic effects, are observed. Ethylene glycol ethers and acetates may enter the environment from manufacturing effluents and emissions and as a result of their use in commercial products.

Exposure to glycol ethers in a population of French men evaluated by measurement of urinary alkoxycarboxylic acids

“…Most glycol ethers have a halflife of less than 1 h and most acidic metabolites have a half-life of less than 24 h (INSERM 1999;Boatman 2001;Boatman and Knaak 2001). However, the halflives of MAA and EAA are 77 h and 42 h, respectively (Groeseneken et al 1988(Groeseneken et al , 1989.…”

“…Numerous studies on laboratory animals and humans have shown that some EG ether derivatives, such as monomethyl ether (EGME) and monoethyl ether (EGEE), have adverse effects on reproduction and development and are toxic to the bone marrow, whereas butyl ether (EGBE) has haemolytic effects (for reviews see ECETOC 1995;INSERM 1999;Boatman 2001;Boatman and Knaak 2001). The toxic effects of glycol ethers are associated with the formation of alkoxycarboxylic acid metabolites (Miller et al 1983;Foster et al 1987).…”

Glycol ethers and semen quality: a cross-sectional study among male workers in the Paris Municipality

“…Numerous toxicological reports have shown that various ethylene glycol ethers, particularly the short-chain ethylene glycol methyl ether (EGME) and ethylene glycol ethyl ether (EGEE), have pronounced adverse effects on sperm production and quality in the rat, mouse and rabbit. [9][10][11] The toxic effects of glycol ethers are thought to be mediated by their alkoxycarboxylic metabolites, which are rapidly eliminated by urines. 12 13 However, very few studies were conducted in human populations.…”

Review of Studies Concerning the Tumorigenicity of 2-Butoxyethanol in B6c3f1 Mice and Its Relevance for Human Risk Assessment

“…Blood from humans, pigs, dogs, cats, and guinea pigs was insensitive to hemolysis induced by BAA at the concentrations used. In sensitive species of common laboratory animals including rats, mice, and rabbits, BE produces a characteristic toxicity that is revealed clinically by the appearance of hemoglobinuria and pathologically by changes in a variety of blood parameters (Boatman & Knaak, 2001). Regardless of the route of administration, hemolysis was regarded as the primary cause of death in rats (Gingell et al, 1998;Sivaroa & Mehendale, 1995).…”