N-Methyl-4-nitroaniline: Physicochemical Properties, Degradation and Toxicity

N-Methyl-p-nitroaniline is a brownish yellow prismatic crystal with a purple hue, with a melting point of 152°C. It is easily soluble in acetone and benzene, slightly soluble in ethanol, and insoluble in water.

Physicochemical properties

N-Methyl-4-nitroaniline(MNA) has low solubility in water; 85 mg L-1 at 25 °C (Boddu et al., 2008a). While the chemical structure of MNA includes both hydrophilic (amino) and hydrophobic (nitro) moieties, the aqueous solubility of MNA is greatly reduced by the N-methyl substitution (Ahmed and Sandler, 2012). Reduction of MNA to N-methyl-p-phenylenediamine (MPD) has been reported in an ethanol-amended anaerobic fluidized bed bioreactor treating MNA and other co-contaminants, such as DNAN and perchlorate (Platten et al., 2013).¹

Degradation

The aerobic degradation of N-Methyl-4-nitroaniline, a compound used to lower the melting temperature in the synthesis of insensitive explosives, has been successfully demonstrated by Pseudomonas sp. strain FK357 isolated from soil. This process marks a significant advancement as prior to this, only anaerobic biotransformation of N-Methyl-4-nitroaniline had been documented.

Toxicity

Classification according to Regulation (EC) No 1272/2008

Acute toxicity, Oral (Category 3), H301 Specific target organ toxicity - repeated exposure (Category 2), H373.

1. Boddu VM, Abburi K, Maloney SW, Damavarapu R. Physicochemical properties of an insensitive munitions compound, N-methyl-4-nitroaniline (MNA). J Hazard Mater. 2008;155(1-2):288-294.