1,1-Dimethylhydrazine

57-14-7

Major use as a storable, high-energy propellant for
liquid-fuelled rockets. 
Apollo rocket fuel was 50:50 mixture of
UDMH and hydrazine with nitrogen tetroxide as the oxidizer.

Also used in the manufacture of N-dimethylaminosuccinamic acid, a
plant growth regulator to retard growth of ornamentals such
as chrysanthemums and to control the vegetation, flowers, or
fruits of food crops, e.g. apples, grapes, peanuts, cherries,
peaches, and tomatoes. 
Also may be used to manufacture
aminimides. 
Photographic chemicals, as a stabilizer for fuel
additives, and as an absorbent for acid gases.

Hygroscopic mobile liquid. 
Fuming, colourless liquid. 
Clear.

Gradually turns yellow. 
Floats and mixes with water.

Fishy or amine-like odour.

Odour threshold, lower: 6 ppm;
Odour threshold, upper: 14 ppm (Sax 1986).

100 % odour recognition level: 41300 ppm at 20 °C (Sax 1986).

UDMH is strongly absorbed and/or decomposed on clay particles. 
The decomposition of UDMH is accelerated by soils as well as
by Montmorillonite and kaolinite clays. 
In dilute solutions,
UDMH can be absorbed and/or decomposed in a relatively short
column of soil containing a moderate amount of clay. 
Slowly
permeable clay soils are likely to prevent spills of UDMH from
reaching groundwater and to minimize runoff. 
However, in
large-scale runoff of rainfall waters, absorbed UDMH may be
carried off in the colloidal clay fraction (Sax 1986).

Flammability: Quite flammable. 
Easily ignited. 
The mixture with
hydrazine may catch fire spontaneously if spilled. 
Flammable in
air. 
Ignites spontaneously in contact with oxidizing agents.

Flashback along vapor trail may occur. 
Burning rate is 3.8
mm/minute (Sax 1986).

Toxic combustion products: Poisonous gases (toxic nitrogen
oxides) are produced when heated and during combustion.

Incomplete oxidation may give hazardous decomposition products
(hydrogen, ammonia, dimethylamine, hydroazoic acid (Sax 1986). 
Explosiveness: Reaction with oxidizers is explosive. 
Vapor may
explode if ignited in an enclosed area. 
Prolonged exposure of
containers of UDMH to fire or heat may result in their violent
rupturing and rocketing due to its decomposition. 
Shock
insensitive (Sax 1986).

Misciple with water with evolution of heat (Sax 1986).

Photooxidation half-life in air:
 0.8hr - 7.7hr,
scientific judgement based upon an estimated rate constant for the
vapor phase reaction with hydroxyl radicals in air
(Howard 1991).

1,1-dimethylhydrazine reacts slowly with molecular oxygen in
the presence of ultraviolet irradiation. 
Oxidation by molecular
oxygen in water will convert hydrazines to diimines and,
ultimately, to nitrogen gas. 
The reaction is catalyzed by metal
ions, particularly copper. 
As a result, 1,1-dimethylhydrazine
is not expected to be an environmentally persistent substance. - 

Hydrazines do not photolyze in the solar actinic region
(wavelength > 290 nm). 
Reactions with OH radical and ozone are
their likely pathways in the atmosphere. 
The latter is the
major fate. 
The major product (60 % yield within 2 to 3
minutes) in the reaction of ozone with UDMH under simulated
atmosperic conditions is dimethylnitrosamine, which upon
irradiation gives dimethylnitramine, (CH3)2NNO2: Formaldehyde,
nitrogen oxides, and nitrous acid. 
Other products from the
reaction of ozone with UDMH are formaldehyde and hydrogen
peroxide. 
Similar products are formed during photooxidation of
UDMH in the presence of NO. 
Another possible product in
N-nitrosodimethylhydrazine (Sax 1986).

Water solutions are weakly alkaline. -  
UDMH forms salts with
mineral acids. 
It is a strong reducing agent oxidized by
compounds such as peroxides, iodates, ferricyanide, and ceric
ions in acid solution. - 
UDMH was oxidized in distilled water
and sterilized and unsterilized lake water. 
Oxidation in
distilled water occurred in the presence or absence of the
cupric ion. 
Oxidation products in lake water were further
degraded when microorganisms were present. -  
Ozonation of UDMH
gives methanol, formaldehyde dimethylhydrazone, formaldehyde
monomethylhydrazone, N-nitrosodimethylamine, dimethyl formamide,
and tetramethyl tetrazene. 
Ozonation reduces the toxicity to
fish and daphnia (Sax 1986).

Aerobic half-life:
8d - 22d, scientific judgement based upon unacclimated
freshwater grab sample data (Howard 1991).

Anaerobic half-life:
32d - 8d, scientific judgement based upon unacclimated aerobic
biodegradation half-life (Howard 1991).

Based on a low octanol/water partition coefficient
1,1-dimethylhydrazine should not bioaccumulate. 
However
1,1-dimethylhydrazine is rapidly absorded into the blood of
dogs and declines very slowly after reaching a peak value which
possibly indicates binding to cellular constituents and
deposition in adipose tissue (Sax 1986).

Target organs are the central nervous system, gastrointestinal
tract, blood, respiratory system, eyes, and skin (Sax 1986).

Vapor irritates eyes, skin, and respiratory tract. -  
Contact
with eyes, skin, or mucous membranes causes chemical burns.

Severe skin irritant effect causes second- and third-degree
burns on short contact. 
Very injurious to the eyes. 
Can be
absorbed through skin to cause systemic intoxication and
convulsions (Sax 1986).

Breathing of vapor causes pulmonary irritation, delayed
gastrointestinal irritation, tremors, and conculsions.

Moderately irritating on inhalation. 
Personnel will not usually
tolerate moderate or high air concentrations. -  
Choking, chest
pain, difficulty in breathing, lethargy, nausea, anoxia, liver
injury. -  
Minimum exposure symptoms: upper respiratory
irritation and muscle tremors. 
Acute symptoms, excitement,
tremors and conculsions. -  
Respiratory irritation leads to
pulmonary edema in some human cases. 
Headache and vomiting may
occur. 
Liver toxicity indicated by a positive cephalin
flocculation test, raised serum glutamic pyruvic transaminase
(SGPT), fatty degeneration in liver biopsies. 
The liver
toxicity is believed to be due to the formation of
dimethylnitrosamine. 
The only continuing effects of acute human
toxicity besides liver injury were complaints of persistent UDMH
odour and taste in the mouth (Sax 1986).

Carcinogenic in mice after oral dosing. 
A proper evaluation of
carcinogenicity in rats could not be made because the doses
were high and only a few liver tumors occurred after a long
latent period. 
No epidemiological information was available to
assess human carcinogenicity. -  
After a lifetime study, most
mice had tumors of the blood vessels (more than half in the
liver; most were angiosarcomas) or lungs (Adenomas and a few
adenocarcinomas) and some had kidney and liver tumors (Sax
1986).

Not mutagenic in the dominant lethal mutation test in mice. 
Did
not produce abnormalities in sperm of mice. 
A UDMH metabolite
was mutagenic to microorganisms in a battery tests (Sax 1986). 
Mutagen data:
mmo, sat, 0.042 mmol/plate;
mma, sat, 0.042 mmol/plate;
mmo, esc, 0.020 mmol/l;
dnr, esc, 0.020 ml/disc;
dnd, esc, 0.001 mmol/l;
pic, esc, 17000 mg/l;
dnr, bcs, 0.020 ml/disc;
mmo, asn, 250 nl/plate;
dns, rat, ipr, 60 mg/kg;
dnd, mus, ipr, 3.5 mmol/kg;
dni, mus, orl, 200 mg/kg;
msc, mus, lym, 5 mmol/l, 24 hr;
hma, mus, sat, 125 mg/kg (Sax 1986).

No mammalian teratogenicity data were found in a 1980
literature survey. 
UDMH was teratogenic to South Africal clawed
toad (Xenopus laevis) embryos (Sax 1986).

Cotton seedlings grown in water containing 1000 ppm UDMH showed a
general flaccidity of the leaves, dehydration, and death at
48 hours. 
True leaves and cotyledons became necrotic. 
When
applied as a spray to the drip point on endive, soybean, pinto
bean, squash, and cotton plants, gave injury indexes (on a
scale of 0 for no injury to 8 for death) of 0 to 2 after 5 days of
2000 ppm, 0 to 4 after 5 days at 6000 ppm, and 0 to 4 after 5 days
at 10000 ppm. 
Injury, when it occurred, developed within
the first day as scattered necrotic spotting and, occasionally,
leaf curl (Sax 1986).

Seedlings of cotton, pinto bean, soybean, and squash suffer
severe injury upon exposure to 25 to 30 ppm UDMH (Sax 1986).

Biological waste treatment detoxification of UDMH is not
recommended. 
Spills could be expected to disrupt the natural
bacterial balance in the aquatic environment and probably
sewage treatment systems (Sax 1986).

100 ppm UDMH caused a marked growth decrease in cultures of the
alga Chlorella pyrenoidosa (Sax 1986).

Flammable, explosive, toxic, a carcinogen, a mutagen, and a
teratogen (Sax 1986).