98 Improved base catalysts for industrial condensation reactions

Abstract

Publisher Summary This chapter demonstrates the viability for solid fixed-bed basic materials to carry out industrially important aldol condensations providing the opportunity to eliminate the use of 30% caustic solution and dramatically reduce the amount of organically contaminated waste caustic produced. The solid base catalysts can be run continuously on-line for hundreds on hours at high conversions and selectivities. The use of solid base catalysts also allows the easier integration of the condensation step with any subsequent hydrogenation steps. The reaction of an aldehyde over a Na/SiO 2 solid base catalyst produces α, β unsaturated aldehyde intermediate. This can be selectively hydrogenated to the saturated aldehyde by the addition of small amounts of Pd to the solid base catalyst or fully hydrogenated to an alcohol over a conventional CuO/ZnO hydrogenation catalyst. With the reaction of butanone there is a high selectivity for reaction at the terminal position of the unsymmetrical ketone. The combination of aldol condensation and hydrogenation offers the possibility of the removal of a process step and consequent capital saving.