Key words: tandem reactions, aldol-crotonic condensation, hydrogenation, hydride transfer, acetone, isopropanol, supercritical conditions, magnesium stannate catalyst, mesityl oxide, isomesityl oxide
The results of a study of tandem reactions - aldol-crotonic condensation and hydrogenation by the mechanism of hydride transfer in acetone-isopropanol mixtures on a МgSnО3 catalyst at 300-400 °C and 12.0 MРa are presented. In these conditions the mixture ofreactants (acetone and isopropanol) and reaction products is in the supercritical state. The temperature dependences of the reactants conversion and the selectivity for condensation and hydrogenation products are considered. It has been established that the hydrogenation of the acetone aldol-crotonic condensation products proceeds by the addition of hydrogen from isopropanol molecule to the C=O-bonds of isomeric mesityl and phorone oxides and is accompanied by the dehydration of alcohols and the isomerization of double C=C-bonds. The optimal conditions for the formation of the carbonyl group hydrogenation products are 350°C and the ratio acetone : isopropanol = 7 : 3. At the acetone to isopropanol ratio 1 : 1, methylpentadienes dominate in the products of mesityl oxide conversion.The hydrogenation reaction also proceeds with the participation of isophorones, the condensation products of three acetone molecules.
doi: 10.34984/SCFTP.2022.17.4.006