Trimethylamine

Trimethylamine is the simplest tertiary amine: a nitrogen atom carrying three methyl groups and a lone pair that makes it a moderately strong, non-nucleophilically-hindered base and a competent nucleophile toward alkylating and acylating agents. At room temperature it is a colourless, flammable gas with an intensely fishy, ammoniacal odour — the same compound responsible for the characteristic smell of decaying fish and of certain floral scents at low concentration. Because the pure gas is awkward to transport and dose, it is supplied almost exclusively as an aqueous solution, typically in the 25 – 45% w/w range, or in pressurised gas cylinders for specialised users.

The molecule's basicity and its three methyl groups are what drive its downstream chemistry: it reacts readily with alkylating agents such as ethylene oxide, epichlorohydrin and alkyl halides to give quaternary ammonium salts, and its own nitrogen is incorporated whole into several important commercial molecules rather than being transformed further.

Where it fits in the synthesis chain

Trimethylamine's largest-volume industrial use is as the feedstock for choline chloride, made by reacting it with ethylene oxide and hydrochloric acid — choline chloride is itself a major animal-feed nutrient additive and a precursor to further quaternary ammonium chemistry. It is also the starting material for tetramethylammonium hydroxide (used in semiconductor photoresist developers and as a strong, non-nucleophilic base), for a range of cationic surfactants and flotation agents, for plant growth regulators and herbicide intermediates, and for strongly basic anion-exchange resins.

Grades we supply

Chelora Chemicals offers Trimethylamine as a 25% or 30% aqueous solution for standard choline and surfactant chemistry, and a 45% aqueous solution for buyers wanting to minimise the water content they ship and store. All grades are supplied with a batch-wise certificate of analysis.

Trimethylamine is manufactured by the catalytic reaction of methanol with ammonia over an acidic solid catalyst (typically an alumina or silica-alumina type) at elevated temperature: 3 CH₃OH + NH₃ → (CH₃)₃N + 3 H₂O. The same reaction simultaneously produces methylamine and dimethylamine, and the ratio of the three products is controlled by the methanol-to-ammonia feed ratio, catalyst choice and reaction conditions. The crude product mixture is separated by fractional distillation, exploiting the different boiling points and basicities of the three methylamines, and the trimethylamine fraction is absorbed into water to the target concentration before packing.

Why the methanol/ammonia route is universal

Direct catalytic amination of methanol is the only industrially practised route to trimethylamine: it is continuous, scalable, and — because all three methylamine co-products have established commercial markets — economically efficient, since none of the three fractions is simply discarded.