Phenols/Cresols/Glycols

Phenol

Phenol is a colorless or white crystalline solid that is usually solid or used in solution.   Structurally, phenol is an aromatic organic compound with the molecular formula C₆H₅OH or C₆H₆O.  It is produced on a large scale from petroleum-derived hydrocarbons.  Phenol is very important in many industries as it serves as a precursor to many materials and useful compounds.  It and its chemical derivatives are essential for production of dyes, papers, plastics, drugs, nylon, epoxy resins, pesticides, insecticides, detergents, and cosmetics. 

Exposure to phenol can have health effects based on whether the exposure was acute or chronic.  Acute effects either via inhalation or skin contact is highly irritating to the skin, eyes, and mucous membranes.  Symptoms may include irregular breathing, muscle weakness and tremors, loss of coordination, convulsions, coma, and respiratory arrest at lethal doses.  Individuals with chronic exposures have reported anorexia, progressive weight loss, diarrhea, vertigo, salivation, and a dark coloration of the urine.

Cresols

Cresols are organic compounds known as methylphenols as they contain a methyl group (-CH₃) attached to a phenol ring.  The position of the methyl group on this ring can make 3 isomers of cresol called ortho-cresol (o-cresol), meta-cresol (m-cresol), and para-cresol (p-cresol).  Cresols are produced either by extraction from coal tar or chemical conversion of closely related compounds.  Similar to their structural backbone phenol, cresols are precursors or synthetic intermediates to other compounds and materials, including plastics, pesticides, pharmaceuticals, and dyes.  Recently, cresols have been used in improving the manufacturing of carbon nanotubes.

Glycols

Ethylene Glycol is an organic compound with the formula (CH₂OH)₂ and exists as a clear, odorless, sweet-tasting, viscous liquid.    It is used most frequently in the manufacturing of polyester and in automotive antifreeze.  Other uses include hydraulic brake fluids, inks, solvents, paints, plastics, films, and cosmetics.  Because of its sweet taste, products which contain it in large quantities present the risk of ingestion by children or animals.  Ingestion of sufficient quantities of ethylene glycol can be fatal as it results in the conversion within the body to several toxic by-products and affect the central nervous system (CNS), then the heart, and finally the kidneys.  Systemic inhalation may produce eye and respiratory tract inhalation, however, it is unlikely to cause systemic toxicity.  As an environmental contaminant, ethylene glycol breaks down in about 10 days in the air and a few weeks in water.

Diethylene Glycol is an organic compound with the formula (HOCH₂CH₂)₂O and is a colorless, practically odorless, poisonous, and hygroscopic liquid with a sweetish taste.  It is used in polyester resins, polyurethanes, and plasticizers.  It is used as a solvent, humectant, a well as a component in brake fluids, lubricants, cooking fuel, personal care products, and artificial fog/smoke. The substance enters the body through inhalation, ingestion, or skin/eye contact.  It can irritate the skin and eyes, but most often enters the body orally and causes kidney and liver failure.  It is considered a poison and because of its adverse effects on humans, diethylene glycol is not allowed for use in food and drugs.  Diethylene glycol has been the source of many mass poisonings worldwide and resulted in numerous deaths.

Propylene glycol is a clear, nearly odorless, faintly sweet-tasting, viscous liquid.  It is an organic compound with the formula CH₃CH(OH)CH₂OH which contains two alcohol groups and is classified as a diol.  Propylene glycol is a synthetic liquid substance that absorbs water and is considered as not persistent in the environment. Propylene glycol is also used to make polyester compounds, de-icing solutions, and as a substitute for ethylene glycol in antifreeze.  The Food and Drug Administration (FDA) has classified propylene glycol as an additive that is “generally recognized as safe” for use in food.  Propylene glycol is used for the creation of theatrical smoke and fog as well as fire simulation for firefighter training.  When used in average quantities, propylene glycol has no measurable effect on human health.