Development of a Semibatch Process for the Synthesis of Methyl Pentenone

A known conventional route to produce methyl pentenone (MPO), a perfumery intermediate used in the fine chemical industry, is through the aldol condensation of acetaldehyde with methyl ethyl ketone (MEK) using an acidic catalyst such as H2SO4. However, the use of homogeneous catalysts makes the overall process inefficient because of multiple side reactions, lower yield, and corrosion. In this work, we emphasized the use of commercially available reusable heterogeneous cation exchange resin Amberlyst-15 as a catalyst to develop the experimentally validated process to improve the MPO yield and to develop the production strategy for MPO production at the industry scale (i.e., 4 TPD) using aspen plus in batch mode. Among different affecting parameters, the semibatch mode of acetaldehyde addition in the batch reactor was found to be the most effective way to improve the MPO selectivity up to 92% from 70% while using batch mode of reaction. The BatchOp model was used to simulate the batch and semibatch reactor operation, and the BatchSep model was used to develop the downstream separation strategy for using batch distillation. The effects of recycling only a pure MEK vs MEK–H2O azeotrope mixture over reaction performance and MPO selectivity were investigated. Overall, the standard operating procedure for MPO production using semibatch mode to achieve nearly 92% MPO selectivity using reusable heterogeneous catalyst Amberlyst-15 and MPO recovery of 95% at the purity of 99% using batch distillation is developed.