The methylamines assume about fifth place, in quantitative terms, amongst the secondary products of methanol. Therefore, the preferred commercial manufacturing process - the stepwise methylation of NH₃ with CH₃OH - is well characterized.

The traditional manufacturers of methylamines are BASF, ICl, Montedison, and recently UCB in Europe, whereas Du Pont and Rohm & Haas are the main suppliers in the USA. The present production capacity for methylamines is estimated to be about 600 000 tonnes per year worldwide, with 170 000, 160 000, and 45 000 tonnes per year in the USA, Western Europe, and Japan, respectively.

In commercial production, methanol and NH₃ are reacted together at 350-500 °C and 15-30 bar in the presence of aluminum oxide, silicate or phosphate:



As pressure has only an insignificant effect on the course of reaction, it is usually conducted at about 20 bar in accordance with industrial requirements.

The alkylation does not stop at the monomethylamine stage; because of the thermodynamic equilibria, all three methylamines are obtained together. The mono- and dialkylation are favored by excess NH₃ and by the addition of H₂O together with the recycling of the trimethylamine. At 500°C with a NH₃/methanol ratio of 2.4: 1, for example, 54% mono-, 26% di-, and 20% trimethylamine are obtained. Side reactions include cleavage to produce CO, CO₂, CH₄, H₂, and N₂. The total selectivity to methylamines reaches about 94%. Due to azeotrope formation, the reaction products are separated in a combination of pressure and extractive distillations.

An important commercial process for methylamines is the Leonard process, with a worldwide capacity of more than 270000 tonnes per year (1993).

In a process carried out by Nitto Chemical, the equilibrium of formation can be shifted by use of an acid zeolite catalyst with a particular pore structure, allowing up to 86 mol% dimethylamine as well as 7 mol% each of mono- and trimethylamine to be generated. A commercial plant has been in operation in Japan since 1984.