Method for synthesizing 1,3-dioxolane derivatives and flow reactor for carrying out the method

Abstract

The subject of the application is a method for the synthesis of 1,3-dioxolane derivatives with the structure presented in the general formula 1, in which the individual substituents R1, R2, R3, R4 independently of each other represent a hydrogen atom (-H) or a methyl group (-CH3) or a hydroxyalkyl group (-CH2OH), characterized in that it comprises the following steps: a) a polyalcohol and a ketone are introduced into the flow reactor tank (1), wherein the molar ratio of the polyalcohol to the ketone in the reaction mixture is equimolar or more preferably with an excess of the ketone, most preferably with an excess of 8 to 10 times that of the ketone, wherein an ion exchange resin and / or a heterogeneous catalyst are introduced into the columns (7) or into the subsequent columns of the reactor in the order of the flow of the reactants, wherein: the ratio of the catalyst mass to the unit volume of the reaction mixture is from 0.625 g / L to 14.0 g / L, preferably from 3.33 to 7.14 g / L;the ratio of the mass of the ion exchange resin to the unit volume of the reaction mixture is from 0.24 g / L to 0.7 g / L, preferably 0.66 g / L; the ratio of the mass of the catalyst to the mass of the ion exchange resin is from 1:5 to 1:30, preferably 1:20, wherein: Re or Ru or In nanoparticles deposited on granulates consisting of: precipitated silica or a metal composite or an acidic ion exchange resin are used as the catalyst; ion exchange resins or precipitated silica are used as the source of H+ ions; a polyol selected from: propylene glycol, ethylene glycol, glycerin is used as the polyalcohol;the ketone used is: acetone, b) then the reactor (1) is closed and the reagents are continuously stirred at a speed of 100 to 600 rpm, preferably 200 rpm, while the reaction mixture is subjected to a temperature of 40°C to 60°C, preferably 55°C, c) then the reaction is carried out for ≥1 minute to 60 minutes, preferably 50 minutes, d) then the post-reaction mixture is returned to the reactor vessel (1) or the post-reaction mixture with the product is collected, e) then the main products in the form of 1,3-dioxolane derivatives constituting cyclic ketals are separated from the collected post-reaction mixture from the by-products constituting intermediate products of ring failure. Another subject of the application is a flow reactor for implementing this method;