N-Methylaniline
N-Methylaniline is an aniline derivative. It is an organic compound with the chemical formula C6H5NH. The substance is a colorless viscous liquid, Samples turn brown when exposed to air. The chemical is insoluble in water. It is used as a latent and coupling solvent and is also used as an intermediate for dyes, agrochemicals and other organic products manufacturing. NMA is toxic and exposure can cause damage to the central nervous system and can also cause liver and kidney failure. The comprehensive evaluation of N-methylaniline by the Bureau for Chemical Substances in Poland, completed in 2024 as a part of the European Union's REACH regulation, has confirmed significant concerns regarding the carcinogenicity and mutagenicity of N-methylaniline.
Use as a fuel additive
N-Methylaniline is a principal component of NMA, a non-traditional antiknock agent increasingly used by petroleum refiners and fuel distributors around the world to increase the octane number of gasoline petrol. It is usually added to gasoline in concentration of around 1.3% volume to avoid high gum levels that can cause increased carbon deposits in engine parts. Higher concentrations are permitted by most regulatory agencies if a detergent and a fuel combustion modifier are added to the component to keep gum formation from happening. NMA blended in those concentrations to gasoline / petrol is not more toxic than the hundreds of chemicals that compose this fuel.Policies on blending NMA in gasoline
China
China has banned the use of most chemical gasoline additives, including NMA, in gasoline standard directive GB17930-2013 dated Dec. 18 2013, which states that “Additives used in gasoline for motor vehicles should not contain recognised harmful substances and should be used by following up with the recommended safe dosage. Chemicals, such as methylal, aniline-type compounds, halogens and those containing phosphorus and silicon, etc. should not intentionally be added in gasoline.”United States
N-Methylaniline as is does not appear on the U.S. Environmental Protection Agency’s List of Registered Gasoline Additives. However, registration can be obtained at higher concentration which maximum authorized dosage depends on a suitable detergent and an effective fuel combustion modifier added to this component.Fuel additives in the United States are regulated under section 211 of the Clean Air Act. The Environmental Protection Agency requires the registration of all fuel additives which are commercially distributed for use in highway motor vehicles in the United States, and may require testing and ban harmful additives. The EPA also regularly reviews the health and net economic benefits of Clean Air Act policies.
The act also requires deposit control additives be added to all gasolines. This type of additive is a detergent additive that acts as a cleansing agent in small passages in the carburetor or fuel injectors. This in turn serves to ensure a consistent air and fuel mixture that will contribute to better gas mileage.