A new continuous-flow methodology is reported for the selective O-methylation of phenol and p-cresol by using dimethyl carbonate as the methylating agent. The reaction has been performed by a continuously fed stirred tank reactor filled with a catalytic bed of poly(ethylene glycol) 1000 and K2CO3 as a base. Thus, operating at atmospheric pressure and at temperatures of 160−200 °C, the phenols have been transformed into their corresponding O-methylated derivatives (anisole and p-methylanisole, respectively) with substantially quantitative yields:  under gradientless conditions, a space velocity of up to 9 × 10-2 h-1 was achieved.

The reaction of dimethyl carbonate (DMC) with different primary aromatic amines has been investigated under batch conditions (autoclave) in the presence of Y-and X-type zeolites. Operating at 120-150 ЊC, highly selective mono-N-methylations are observed for anilines even when they are deactivated by either electronic effects or steric hindrance (G᎐C 6 H 4 NH 2 , G = p-NO 2 , p-CN, o-CO 2 CH 3 and 2,6-dimethylaniline); typical selectivities for the formation of the corresponding mono-N-methyl derivatives [ArNH(CH 3 )] are in the range 92-98%, at a substrate conversion of 72-93%. A synergic effect between the reactivity of DMC (acting both as a methylating and as a reversible methoxycarbonylating agent) and the dual acidbase properties of zeolites is considered to be responsible for the unusually high selectivity observed; accordingly, a reaction mechanism is discussed, involving carbamates (ArNHCO 2 CH 3 ) and N-methylcarbamates [ArN(CH 3 )CO 2 CH 3 ] as intermediates. The reaction is an example of a synthesis with low environmental impact: it couples the use of a non-toxic methylating agent (DMC, in place of the highly toxic methyl halides or dimethyl sulfate) with eco-friendly catalysts (zeolites) in a waste-free process.

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Mono‐C‐methylation of arylacetonitriles and methyl arylacetates by dimethyl carbonate: A general method for the synthesis of pure 2‐arylpropionic acids. 2‐phenylpropionic acid reactant: dimethyl carbonate (DMC) product: 2‐phenylpropionic acid (3) intermediate: 2‐phenylpropionitrile (2)

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