Formation of neutral methylcarbamic acid (CH3NHCOOH) and methylammonium methylcarbamate [CH3NH3+][CH3NHCO2-] at low temperature.

We study low temperature reactivity of methylamine (CH3NH2) and carbon dioxide (CO2) mixed within different ratios, using FTIR spectroscopy and mass spectrometry. We report experimental evidence that the methylammonium methylcarbamate [CH3NH3(+)][C3NHCO2(-)] and methylcarbamic acid (CH3NHCOOH) are formed when the initial mixture CH3NH2:CO2 is warmed up to temperatures above 40 K. An excess of CH3NH2 favors the carbamate formation while an excess of CO2 leads to a mixture of both methylammonium methylcarbamate and methylcarbamic acid.