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Methyl Isobutyl Ketone
Description: Methyl isobutyl ketone (C.A.S. 108-10-1) is a colorless liquid that is used as a solvent for vinyl, epoxy, acrylic and natural resins, nitrocellulose, paints, varnishes, lacquers, protective coatings, rare metal extraction, and dyes. It is used as a denaturant for rubbing alcohol, a synthetic flavoring adjuvant, and a fruit flavoring. It is used in extracting uranium from fission products, dewaxing mineral oils, manufacturing antibiotics, dry-cleaning preparations, and the synthesis of methyl isobutyl carbinol. It occurs naturally in oranges, grapes, and vinegar. Chemical properties: Methyl isobutyl ketone has a faint ketonic and camphor odor. It is classified under the Clean Air Act as a volatile organic compound. It is moderately soluble in water, and soluble in alcohol, ether, acetone, benzene, and chloroform. It is miscible with most organic solvents. It is reactive or incompatible with strong oxidizers, potassium, and tert-butoxide. It is highly flammable and will be easily ignited by heat, sparks, or flame. Its vapors may form explosive mixtures with air and may travel to the source of ignition and flash back. The vapor may explode if ignited in an enclosed area. Most of its vapors are heavier than air, and its liquids are lighter than water. Methyl isobutyl ketone ignites on contact with potassium-t-butoxide. It can react vigorously with reducing materials. Synonyms for methyl isobutyl ketone include hexone, isobutyl methyl ketone, 4-methyl-2-pentanone, and isopropyl acetone. Identification: Health effects: Exposure to methyl isobutyl ketone may cause gastrointestinal disturbances and central nervous system impairment, headache, nausea, vomiting, and respiratory tract irritation. Chronic exposure may cause axonal neuropathy, paresthesia, and muscle weakness. Ingestion of methyl isobutyl ketone may cause central nervous system depression, respiratory depression, dyspnea, pulmonary aspiration, and corrosive effects. Inhalation may cause coma, nausea, headache, vertigo, incoordination, central nervous system depression, narcosis, dizziness, tremors, cardiorespiratory failure, and eye, nose, and throat irritation. Exposure Values: Economics: U.S. manufacturers of methyl isobutyl ketone are :Eastman Kodak Company, Longview, TX; Shell Oil Company, Deer Park, TX; and Union Carbide Corporation, Institute, WV. Regulation: The U.S. Occupational Safety and Health Administration (OSHA) issues permissible exposure limits for methyl isobutyl ketone. Methyl isobutyl ketone is regulated under the Emergency Planning and Community Right-to-Know Act; Comprehensive Environmental Response, Compensation, and Liability Act; Toxic Substances Control Act; Clean Air Act, as a hazardous air pollutant and volatile organic compound; and Resource Conservation and Recovery Act. Under the Emergency Planning and Community Right-to-Know Act, releases of more than one pound of methyl isobutyl ketone into the air, water, or land must be reported annually and entered into the national Toxic Release Inventory (TRI). National Overview of 1998 Toxics Release Inventory See EPA's Toxic Release Inventory. Notations: The NIOSH recommended exposure limits (RELs) are time-weighted average (TWA) concentrations for up to a 10-hour workday during a 40-hour workweek. A short-term exposure limit (STEL) is designated by "ST" preceding the value; unless noted otherwise, the STEL is a 15-minute TWA exposure that should not be exceeded at any time during a workday. A ceiling REL is designated by "C" preceding the value. Any substance that NIOSH considers to be a potential occupational carcinogen is designated by the notation "Ca." The OSHA permissible exposure limits (PEL) are found in Tables Z-1, Z-2, and Z-3 of the OSHA General Industry Air Contaminants Standard (29 CFR 1910.1000). Unless noted otherwise, PEL are TWA concentrations that must not be exceeded during any 8-hour workshift of a 40-hour workweek. A STEL is designated by "ST" preceding the value and is measured over a 15-minute period unless noted otherwise. OSHA ceiling concentrations (designated by "C" preceding the value) must not be exceeded during any part of the workday; if instantaneous monitoring is not feasible, the ceiling must be assessed as a 15-minute TWA exposure. In addition, there are a number of substances from Table Z-2 (e.g., beryllium, ethylene dibromide, etc.) that have PEL ceiling values that must not be exceeded except for specified excursions. For example, a "5-minute maximum peak in any 2 hours" means that a 5-minute exposure above the ceiling value, but never above the maximum peak, is allowed in any 2 hours during an 8-hour workday. Information Sources:
Originally published in Environment Writer by the National Safety Council. Reprinted with permission. Environment Writer Metcalf Institute for Marine and Environmental Reporting University of Rhode Island Graduate School of Oceanography Office of Marine Programs Narragansett, RI 02882 Tel: 401-874-6211; Fax: 401-874-6485 Disclaimer * Copyright 2002-2006 * All rights reserved. * University of Rhode Island |