From batch to continuous sustainable production of 3-methyl-3-penten-2-one for synthetic ketone fragrances

3-Methyl-3-penten-2-one (3M3P) is an essential intermediate for the production of synthetic ketone fragrances such as Iso E Super®. The traditional batch production of 3M3P suffers from low selectivity and efficiency along with the drawbacks of using homogeneous catalysts, hence major improvements are needed to upgrade the production in a sustainable way. This work is the first to provide an eco-efficient replacement of batch stirred tank reactors (BSTR) with continuous technologies based on a fixed bed reactor (FBR) and reactive distillation column (RDC), combined with using heterogeneous catalysts in order to intensify the synthesis of 3M3P. The effect of reaction conditions on 3M3P synthesis was investigated experimentally, and rigorous simulations were used to scale-up the processes. The 3M3P yields are similar in BSTR and FBR, but the FBR-based alternative can reduce the energy use by 34.4% and total annual cost (TAC) by 48.4%. The process combining RDC and FBR allows yields of up to 95.8% (about 13% higher than in BSTR), due to the ability of RD to remove continuously the intermediate from the reactive section and avoid the side reactions. Compared to the traditional BSTR based process, the energy usage for the RDC+FBR based technology is reduced by 42%, TAC is 53% lower, the CO2 emissions are reduced by 11.7% and the waste by 87.3%, while the mass efficiency is improved by 11.5%. The results of this work provide a strong basis for development, design and improvement of more sustainable 3M3P production technologies.