Full Answer
N,N-Dimethylaniline's production and use as a polymerization catalyst and as an intermediate for pharmaceuticals and dyes (1) may result in its release to the environment through various waste streams (SRC).
The rate constant for the vapor-phase reaction of N,N-dimethylaniline with photochemically-produced hydroxyl radicals is 1.48X10-10 cu cm/ molecule-sec at 25 °C (1). This corresponds to an atmospheric half-life of about 2 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm (2). The rate constant for the vapor-phase reaction of N,N-dimethylaniline with ozone has been experimentally determined to be 9.1X10-18 cu cm/molecule-sec at room temperature which corresponds to an atmospheric half-life of 29 hrs at an atmospheric concn of 7.2X10+11 ozone molecules/cu cm (3). N,N-Dimethylaniline is degraded in aqueous environments by reaction with photochemically-produced hydroxyl radicals (SRC); the rate constant for this reaction is 1.4X10+10 cu cm/molecule- sec (4). This corresponds to an aqueous half-life of about 34 days at an aqueous concentration of 1.0X10-17 hydroxyl radicals per cu cm (5). The rate constant for the reaction between N,N-dimethylaniline and singlet oxygen has been determined to be 1X10+8 L/mole-sec (5); assuming the steady-state concentration of singlet oxygen in natural water is 2X10-13M (5), the half-life for this reaction can be estimated to be 9.6 hrs (SRC). N,N-Dimethylaniline is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions (6). Exposure of a dilute aqueous solution of N,N-dimethylaniline to fluorescent lamps having a continuous spectrum from 300-400 nm resulted in a 50% degradation in approximately 14 min (7); therefore, N,N-dimethylaniline may be susceptible to direct photolysis by sunlight (SRC).
SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.
AEROBIC: Using a mixed municipal/industrial activated sludge, 0-3% of N,N-dimethylaniline was removed over a 6 hr period at a concentration of 20 mg/L. When an industrial activated sludge that was adapted to N,N-dimethylaniline was used, 100% of the total organic carbon was removed after 6 days at a concentration of 400 mg/L. However, this test indicates that stripping may be the most important elimination process since there was no indications that biodegradation had occurred. In another test, both a municipal non-acclimated and an acclimated activated sludge were used to study the biodegradation. The non-acclimated sludge reached less than 10% of its ThOD after 28 days at a concentration of 50-200 mg/L of N,N-dimethylaniline while at the same concentration, the acclimated sludge reached 22% of its ThOD in 5 days (1). N,N-Dimethylaniline, present at 100 mg/L, reached 1.9% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test (2).
Dimethylaniline is produced from aniline and methanol under pressure in the presence of acidic catalysts or by passing dimethyl ether and aniline vapor over highly activated aluminum oxide at 230-295 °C.
N,N-Dimethylaniline is used as an intermediate in the manufacture of dyes and other substances. Acute (short-term) inhalation exposure to N,N-dimethylaniline has resulted in effects on the central nervous system (CNS) and circulatory system, with headache, cyanosis, and dizziness in humans. Effects on the blood have been reported in exposed workers.
N,n-dimethylaniline appears as a yellow to brown colored oily liquid with a fishlike odor. Less dense than water and insoluble in water. Flash point 150°F. Toxic by ingestion, inhalation, and skin absorption. Used to make dyes and as a solvent.
N,N-Dimethylaniline ( DMA) is an organic chemical compound, a substituted derivative of aniline. It consists of a tertiary amine, featuring dimethylamino group attached to a phenyl group. This oily liquid is colourless when pure, but commercial samples are often yellow.
DMA is a key precursor to commercially important triarylmethane dyes such as malachite green and crystal violet. DMA serves as a promoter in the curing of polyester and vinyl ester resins. DMA is also used as a precursor to other organic compounds. A study of the in vitro metabolism of N,N -dimethylaniline using guinea pig and rabbit preparations and GLC techniques has confirmed N -demethylation and N -oxidation as metabolic pathways, and has also established ring hydroxylation as a metabolic route. Its derivative 2,4-dimethylaniline is a recalcitrant degradant of the pesticide amitraz and is also an industrial pollutant which is genotoxic, teratogenic and carcinogenic.
DMA was first reported in 1850 by the German chemist A. W. Hofmann, who prepared it by heating aniline and iodomethane: DMA is produced industrially by alkylation of aniline with methanol in the presence of an acid catalyst: Similarly, it is also prepared using dimethyl ether as the methylating agent.
Dimethylaniline undergoes many of the reactions expected for an aniline, being weakly basic and reactive toward electrophiles. For example, it is nitrated to produce tetryl, a derivative with four nitro groups which was once used as explosive. It is lithiated with butyllithium.