Introduction to the process of synthesizing 3-pentanone via propionic acid condensation in a fixed-bed reactor

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Introduction to the Process of Synthesizing 3-Pentanone by Propionic Acid Condensation in a Fixed-Bed Reactor I. Technical Background As an important intermediate in the fine chemical industry and a high-performance solvent, 3-pentanone is widely used in pharmaceutical synthesis, fragrance production, polymer materials, and special coatings. It has a symmetrical molecular structure, excellent solubility, and low volatility, making it highly suitable for use in high-end electronic cleaning agents and environmentally friendly coatings. With the development of green chemical processes, there is a growing demand in the market for high-purity, low-toxicity ketone solvents. To meet market demands, this project has developed a green process for synthesizing 3-pentanone from propionic acid via a condensation reaction. This process carries out the reaction in a tubular fixed-bed reactor; the CO₂ generated as a byproduct is removed using a flash tank, unreacted propionic acid is separated and recovered through a fractionation tower, and the azeotrope between water and 3-pentanone is effectively broken down, thereby enabling the synthesis of high-purity 3-pentanone. Compared with other methods such as the 3-pentanol oxidation process and the C5 process, this process offers better environmental compatibility, a higher degree of continuous integration, higher separation efficiency, and lower energy consumption, making it suitable for industrial continuous production. II. Process Route: The team has successfully developed a fixed-bed reactor technology for the condensation synthesis of 3-pentanone using propionic acid, which features an independent intellectual property portfolio and includes an efficient catalyst system, a continuous reaction process, and an energy-saving separation procedure. This technology has operated stably in a pilot plant, with excellent product purity and process economicity metrics. The online service life of industrial catalysts exceeds 3,000 hours, meeting the requirements for large-scale continuous production. III. Technical Features (1) Adoption of a heterogeneous fixed-bed continuous reaction process: high catalyst activity, good stability, long service life, and excellent regeneration performance ； (2) Efficient CO₂ removal: The CO₂ generated during the reaction is removed promptly through a flash tank, preventing non-condensable gases from interfering with subsequent distillation operations and reducing the load on the separation equipment ； (3) Efficient recycling of raw materials: By precisely controlling the operating parameters in the roughing tower, efficient separation of unreacted propionic acid is achieved, with a recovery rate of ≥98%; the overall utilization rate of raw materials increases by 15%–20% ； (4) Efficient disruption of the azeotrope between water and 3-pentanone: Through the coordinated operation of the 3-pentanone purification tower and the stripping tower, along with the organic-phase/water-phase dual circulation loop formed by the separation tank, it is possible to effectively break the azeotrope between water and 3-pentanone without the need to add any third component; the purity of the 3-pentanone product reaches over 99.9%, with a low water content