• Unsymetrical dimethyl hydrazine
  • UDMH
  • Dimazine
  • N,N-Dimethylhydrazine
DescriptionFuming colorless liquid, gradually turns yellow in air, hygroscopic, ammonia or fish-like odor.
UsesThe base in rocket fuel formulations.

Registry Numbers and Inventories.
EC Index Number007-012-00-5
EC ClassHighly flammable; Carcinogenic Category 2; Toxic; Corrosive; Dangerous for the Environment
EC Risk PhraseR 45 11 23/25 34 51/53
EC Safety PhraseS 53 45 61
RTECS class Tumorigen; Mutagen; Reproductive Effector; Human Data
UN (DOT)1163
Beilstein Reference4-04-00-03322
EPA OPP 600018
Swiss Giftliste 1G-1561
Austrailia AICSListed
New ZealandListed
Japan ENCS (MITI) Listed
Korea ECLListed

Odor Threshold Odor threshold 12.0 mg/m3
Formula C2H8N2
Formula mass 60.10
Melting point, C -58
Boiling point, C 63
Vapor pressure, mmHg 157
Vapor density (air=1) 1.94
Saturation Concentration 136000 ppm (13.6%) at 20 C (calculated)
Critical temperature 250
Critical pressure 53.5
Density 0.801 g/cm3 (11 C)
Solubility in water Very soluble
Viscosity 0.492 millipascal second @ 25C
Surface tension 24.09 g/s2 at 25 C
Refractive index 1.0001
pKa/pKb 6.79 (pKb)
Heat of fusion 10.1 kJ/mol
Heat of vaporization 32.6 kJ/mol
Heat of combustion -1979 kJ/mol

Hazards and Protection.
Storage Keep away from heat, sparks, and flame. Keep away from sources of ignition. Keep container closed when not in use. Store in a tightly closed container. Store in a cool, dry, well-ventilated area away from incompatible substances. Refrigerator/flammables.
Handling Wash thoroughly after handling. Use only in a well ventilated area. Ground and bond containers when transferring material. Empty containers retain product residue, (liquid and/or vapor), and can be dangerous. Keep container tightly closed. Avoid contact with heat, sparks and flame. Do not get on skin or in eyes. Avoid ingestion and inhalation. Discard contaminated shoes. Do not pressurize, cut, weld, braze, solder, drill, grind, or expose empty containers to heat, sparks or open flames.
Protection Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators A respiratory protection program that meets OSHA's 29 CFR 1910.134 and ANSI Z88.2 requirements or European Standard EN 149 must be followed whenever workplace conditions warrant a respirator's use. Follow the OSHA respirator regulations found in 29CFR 1910.134 or European Standard EN 149. Always use a NIOSH or European Standard EN 149 approved respirator when necessary.
Small spills/leaks Absorb spill with inert material, (e.g., dry sand or earth), then place into a chemical waste container. Clean up spills immediately, using the appropriate protective equipment. Remove all sources of ignition. Use a spark-proof tool. Provide ventilation. A vapor suppressing foam may be used to reduce vapors.
Disposal code 9
Stability Stable under normal temperatures and pressures.
Incompatibilities Halogens, mercury, strong acids, strong oxidizing agents, rubber, plastics.
Decomposition Nitrogen oxides, carbon monoxide, irritating and toxic fumes and gases, carbon dioxide, nitrogen.

Flash Point,C1
Autoignition, C249
Upper exp. limit, %45
Lower exp. limit, %2
Fire fightingWear a self-contained breathing apparatus in pressure-demand, MSHA/NIOSH (approved or equivalent), and full protective gear. During a fire, irritating and highly toxic gases may be generated by thermal decomposition or combustion. Use water spray to keep fire-exposed containers cool. Containers may explode in the heat of a fire. Will be easily ignited by heat, sparks or flame. Extinguishing media: For small fires, use dry chemical, carbon dioxide, water spray or alcohol-resistant foam. For large fires, use water spray, fog, or alcohol-resistant foam. Use water spray to cool fire-exposed containers. Water may be ineffective. Do NOT use straight streams of water.
Fire potentialQuite flammable. Easily ignited. The mixture with hydrazine.
HazardsVapor may explode if ignited in an enclosed area. Vapors may travel to a source of ignition and flashback. Runoff to sewer may create fire or explosion hazard. When it decomposes, 1,1-dimethylhydrazine gives off toxic nitrogen compound fumes. Dissolves, swells, and disintegrates many plastics. Dangerous when exposed to heat, flame, or oxidizers. Hazardous polymerization may not occur.
Combustion productsToxic oxides of nitrogen are produced during combustion of this material.

Exposure limit(s)OSHA PEL: TWA 0.5 ppm (1 mg/m3) skin NIOSH REL: Ca C 0.06 ppm (0.15 mg/m3) 2-hr See Appendix A NIOSH IDLH: Potential occupational carcinogen 15 ppm
CarcinoginG-A3, I-2B, N-2, CP65
Exposure effects Possible cancer hazard based on tests with laboratory animals. Chronic exposure may cause liver damage.
   IngestionHarmful if swallowed. May cause severe and permanent damage to the digestive tract. Causes gastrointestinal tract burns. May cause liver damage.
   InhalationHarmful if inhaled. Causes chemical burns to the respiratory tract. Exposure produces central nervous system depression. Vapors may cause dizziness or suffocation.
   SkinCauses skin burns. May be harmful if absorbed through the skin.
   Eyes Causes eye burns. May result in corneal injury.

First aid
   IngestionDo NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
   InhalationGet medical aid immediately. Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. DO NOT use mouth-to-mouth respiration.
   Skin Get medical aid immediately. Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Wash clothing before reuse. Destroy contaminated shoes.
   EyesGet medical aid immediately. Do NOT allow victim to rub or keep eyes closed. Extensive irrigation is required (at least 30 minutes).

UN number1163
Response guide131
Hazard class 6.1
Packing GroupI  
HS Code 2928 00 90 
Std. Transport # 4921202