Agile Green Process Design for the Intensified Kolbe–Schmitt Synthesis by Accompanying (Simplified) Life Cycle Assessment

In order to investigate the potential for process intensification, various reaction conditions were applied to the Kolbe–Schmitt synthesis starting from resorcinol. Different CO₂ precursors such as aqueous potassium hydrogencarbonate, hydrogencarbonate-based ionic liquids, DIMCARB, or sc-CO₂, the application of microwave irradiation for fast volumetric heating of the reaction mixture, and the effect of harsh reaction conditions were investigated. The experiments, carried out in conventional batch-wise as well as in continuously operated microstructured reactors, aimed at the development of an environmentally benign process for the preparation of 2,4-dihydroxybenzoic acid. To provide decision support toward a green process design, a research-accompanying simplified life cycle assessment (SLCA) was performed throughout the whole investigation. Following this approach, it was found that convective heating methods such as oil bath or electrical heating were more beneficial than the application of microwave irradiation. Furthermore, the consideration of workup procedures was crucial for a holistic view on the environmental burdens

In Situ Synthesis of Photocatalytically Active Hybrids Consisting of Bacterial Nanocellulose and Anatase Nanoparticles

Bacterial nanocellulose (BNC) is an extraordinary biopolymer with a wide range of potential technical applications. The high specific surface area and the interconnected pore system of the nanofibrillar BNC network suggest applications as a carrier of catalysts. The present paper describes an in situ modification route for the preparation of a hybrid material consisting of BNC and photocatalytically active anatase (TiO₂) nanoparticles (NPs). The influence of different NP concentrations on the BNC biosynthesis and the resulting supramolecular structure of the hybrids was investigated. It was found that the number of colony forming units (CFUs) and the consumption of glucose during biosynthesis remained unaffected compared to unmodified BNC. During the formation of the BNC network, the NPs were incorporated in the whole volume of the accruing hybrid. Their distribution within the hybrid material is affected by the anisotropic structure of BNC. The photocatalytic activity (PCA) of the BNC-TiO₂ hybrids was determined by methanol conversion (MC) under UV irradiation. These tests demonstrated that the NPs retained their PCA after incorporation into the BNC carrier structure. The PCA of the hybrid material depends on the amount of incorporated NPs. No alteration of the photocatalyst’s efficiency was found during repeated PCA tests. In conclusion, the in situ integration of photocatalytically active NPs into BNC represents an attractive possibility to extend its fields of application to porous filtering media for drinking water purification and air cleaning

Eco-efficiency Analysis for Intensified Production of an Active Pharmaceutical Ingredient: A Case Study

This article presents results on cost and performance benefit analysis of optimization and intensification activities of a pharmaceutical process. A batch process for the production of a low-volume, high-value active pharmaceutical ingredient, developed at Sanofi (France), has been used as a case study. With the scale of 100 kg/y and a product price of a few thousands Euros per kilogram, also following a general trend in pharmaceutical industry, this process is supposed to be an ideal candidate for continuous, modular plant production of a highly potent drug. It was aimed to keep the information gathered generic, i.e. to stand for the whole class of similarly produced drugs. The impact of various chemical process parameters on the overall production costs has been investigated and process performance represented in terms of operation time, waste, and resource usage as the main process metrics. Five optimized and intensified scenarios were compared to the reference case operated at a Sanofi site: intensified reaction, continuous processing, alternative catalysts, change of solvent, change in the purification sequence, recovery of the key product, and intensified drying option. The analysis has shown that, under the assumptions used, an intensified millireactor-based process with a subsequent continuous postprocessing brings the most benefits in terms of cost, while its process performance, although equal or slightly better than batch, still can be optimized. The total product cost is then reduced by 35%, while the operating time is 27% lower than the base case, with 47% less labor needed compared to that for the reference case. First studies on ecological impact by the University of Jena confirm these promising findings and are outlined hereinwith its own paper on the respective details to follow. The results are now undergoing experimental validation in the newly developed compact container plant of Evonik