2-Mercaptoethanol

2-Mercaptoethanol (CAS 60-24-2) is the chemical compound with the formula HOCH₂CH₂SH. It is a hybrid of ethylene glycol (HOCH₂CH₂OH) and 1,2-ethanedithiol (HSCH₂CH₂SH). It is widely used because the hydroxyl group confers solubility in water and lowers the volatility. Due to its diminished vapor pressure, its odor, while unpleasant, is less objectionable than related thiols. It may be prepared by the reaction of hydrogen sulfide on ethylene oxide. 2-ME causes irritation to the nasal passageways and respiratory tract upon inhalation, irritation of the skin, vomiting and stomach pain through ingestion, and potentially death if severe exposure occurs. 2-ME has a very low odor threshold (0.12-0.64ppm) and smells like the odorant used in natural gas. Symptoms of exposure may include burning sensation, coughing, wheezing, laryngitis, shortness of breath, headache, nausea, and vomiting. After repeated exposure the substance is hepatotoxic and toxic for aquatic organisms.