Chemical Properties
4,4’-Diaminodiphenylmethane is a pale yel-
low crystalline solid (turns light brown on contact with air)
with a faint amine-like odor.
Uses
In 1987, about 600 million lb of MDA was produced in the
United States captively as a chemical intermediate; additional
amounts were also imported. Approximately 99% of
theMDAand polymericMDAproduced in the United States,
usually by the acid-catalyzed reaction of aniline with formaldehyde,
is used as a chemical intermediate in the closedsystem
production of methylene diisocyanate (MDI) and
polymeric MDI, which are used extensively in the manufacture
of rigid semiflexible polyurethane foams for automobile
safety cushioning, and also in the production of wire coatings.
MDA is also used as a hardener or curing agent for
epoxy resins (providing cross-linkages), in the manufacture
of various natural and synthetic rubbers as an antioxidant, in
the production of polyurethane elastomers, as a curing agent
for neoprene, as an antioxidant in rubber, in the preparation of
polyamide–imide resins, as a metal deactivator fuel additive
(neutralizes the catalytic effect of copper associated with fuel
oxidation), and in the production of polymers for synthetic
fibers in the textile industry.
General Description
Light beige fine powder.
Air & Water Reactions
May be sensitive to prolonged exposure to air and light. Water soluble.
Reactivity Profile
In aqueous solution behaves as an acid. Materials in this group are generally soluble in water. The resulting solutions contain moderate concentrations of hydrogen ions and have pH's of less than 7.0. They react as acids to neutralize bases. These neutralizations generate heat, but less or far less than is generated by neutralization of inorganic acids, inorganic oxoacids, and carboxylic acid. They usually do not react as either oxidizing agents or reducing agents but such behavior is not impossible. Many of these compounds catalyze organic reactions.
Fire Hazard
Flash point data for 4,4'-methylenedianilinium dichloride are not available; however, 4,4'-methylenedianilinium dichloride is probably combustible.
Safety Profile
Confirmed carcinogen
with experimental carcinogenic and
neoplastigenic data. Mutation data reported.
When heated to decomposition it emits
toxic fumes of NOx and HCl.
Potential Exposure
Used as an intermediate and as a curing
agent. Approximately 99% of the DDM produced is con-
sumed in its crude form (occasionally containing not more
than 50% DDM and ply-DDM) at its production site by reac-
tion with phosgene in the preparation of isocyanates and poly-
isocyanates. These isocyanates and polyisocyanates are
employed in the manufacture of rigid polyurethane foams
which find application as thermal insulation. Polyisocyanates
are also used in the preparation of the semiflexible polyure-
thane foams used for automotive safety cushioning. DDM is
also used as: an epoxy hardening agent; a raw material in the
production of polyurethane elastomers; in the rubber industry
as a curative for Neoprene and as an antifrosting agent (anti-
oxidant) in footwear; a raw material in the production of
Quana nylon; and a raw material in the preparation of poly
(amide-imide) resins (used in magnet wire enamels).
Shipping
UN2651 4,40
-Diaminodiphenyl methane, Hazard
Class: 6.1; Labels: 6.1-Poisonous materials.
Incompatibilities
Dust forms and explosive mixture
with air. May polymerize in temperatures .125℃
. A weak
base. Incompatible with strong oxidizers (chlorates, nitrates,
peroxides, permanganates, perchlorates, chlorine, bromine,
fluorine, etc.); contact may cause fires or explosions. Keep
away from alkaline materials, strong acids. Flammable gas-
eous hydrogen may be generated in combination with strong
reducing agents, such as hydrides
.
Waste Disposal
Controlled incineration
(oxides of nitrogen are removed from the effluent gas by
scrubbers and/or thermal devices).
