Abstract: The process claimed enables three separate streams to be obtained, from mixtures containing methanol, ethanol, n-propanol, isobutanol, water and other both low- and high-boiling compounds, of which one is anhydrous basically consisting of methanol and ethanol (I), one containing most of the n-propanol present in the mixture fed (II), together with small quantities of methanol, ethanol, isobutanol and water, and one containing most of the isobutanol and high-boiling compounds present in the above mixture (III), by the use of three rectifying columns, stream (I) being taken from a lateral point of the first column, stream (II) obtained from the head of the second column, stream (III) obtained from the bottom of the second column.

Abstract: A process for the preparation of dialkylcarbonates by reacting an alcohol with a cyclic carbonate, wherein the reaction is carried out in the presence of an organic base, preferably a tertiary aliphatic amine, at a temperature of between 50.degree. and 150.degree. C and at a pressure of between 0.1 and 10 kg./sq.cm., the conversion of dialkylcarbonate being selective and avoiding the need of removing inorganic by-products.