cigarette smoke (NTP 2000). UDMH is also used in the manufacture of N-dimethylaminosuccinamic acid, a plant growth regulator.

UDMH is used primarily in military applications, as a storable, high-energy propellant for liquid-fueled rockets, in fuel for thrusters, and in small electrical power-generating units. Development of UDMH started in the Soviet Union in 1949 (Wade 2003) and became the storable liquid fuel of choice by the mid-1950s. It is used, in effect, in all storable liquid rocket engines, with the exception of some orbital maneuvering engines made in the United States, in which monomethylhydrazine is preferred because of its higher density and performance (Wade 2003). UDMH has been widely used as the fuel source for a number of Russian, European, and Chinese rockets (Zelnick et al. 2003).

TABLE 10-1 Physical and Chemical Properties of UDMH

Formula

C2H8N2

Chemical name

Dimethylhydrazine

Synonyms

Unsymmetrical dimethylhydrazine

U-Dimethylhydrazine

UDMH

DMH

Dimethylhydrazine

AS-Dimethylhydrazine

Asymmetric dimethylhydrazine

ASYM dimethylhydrazine

Dimazin

Dimazine

N,N-Dimethylhydrazine

Dimethylhydrazine unsymmetrical

CAS number

57-14-7

Physical description

Liquid (HSDB 2005)

Molecular weight

60.10 (HSDB 2005)

Boiling point

63.9°C (HSDB 2005)

Freezing/melting point

−58°C (HSDB 2005)

Flash point (closed cup)

−15°C (HSDB 2005)

Liquid density at 25°C

0.782 (HSDB 2005)

Vapor density

1.94 (HSDB 2005)

Vapor pressure

156.8 mm Hg at 25°C

Solubility

Soluble in water and ethanol; miscible with dimethylformamide, hydrocarbons, alcohol, and ether

Specific gravity

0.782 at 25°C

Odor threshold

0.3 ppm (Rumsey and Cesta 1970)

1.7 ppm (Amoore and Hautala 1983)

6-14 ppm (Jacobson et al. 1955)

Conversion factor at 25°C, 1 atm

1 ppm = 2.5 mg/m3 (HSDB, 2005)



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement