A process for producing dimethyl carbonate (DMC) from methanol and urea, using polyphosphoric acid (PPA) as the catalyst, has been carried out by conducting the reaction continuously under reactive rectifying conditions on a laboratory scale. Several operational variables which have an influence on the yield of DMC, such as the total feed flow rate, bottom temperature, pressure, reflux ratio, mass ratio of the reactants, the concentration of the catalyst and the stirring speed, were investigated to achieve an optimum operation. Under these optimized settings, the highest yield of DMC obtained was 92.2%. A high concentration and purity of DMC in the overhead products, more than 17%, was gained in the reactive rectifying conditions. (c) 2006 Published by Elsevier B.V.