Methacrylic Acid Purification via Crystallization and Thermal Cleavage

The patent extracts and removes dimers and oligomers from the purification process by using a specific adsorbent material that selectively absorbs these impurities. This allows the distillation process to achieve high purity while preventing the formation and accumulation of harmful dimers and oligomers through selective removal rather than just separation.

The patent introduces an intermediary substance (adsorbent material) that mediates between the distillation process and the impurities. This intermediary selectively interacts with dimers and oligomers, allowing them to be removed from the main product stream without affecting the purity achievement of the distillation process itself.

The patent extracts maleic acid and maleic anhydride from the thermal cleavage process by using a selective adsorbent that removes these specific impurities. This allows thermal cleavage to convert dimers to monomers while simultaneously preventing the accumulation of maleic acid and maleic anhydride through their selective removal from the reaction mixture.

The patent converts the harmful effect of thermal cleavage (which produces unwanted impurities) into a beneficial process by using the heat and reaction conditions to facilitate both dimer-to-monomer conversion and the subsequent adsorption removal of the resulting impurities. The thermal energy that would normally cause problems is harnessed to drive the beneficial conversion and impurity removal.

The patent merges multiple purification functions into a single integrated process. The adsorbent unit is incorporated into the distillation or thermal cleavage process, allowing simultaneous achievement of dimer removal, monomer conversion, and impurity separation in one unified operation rather than requiring separate sequential steps, thereby reducing overall energy consumption.

The adsorbent material serves multiple functions: it removes dimers, converts them to monomers, and simultaneously eliminates maleic acid and maleic anhydride impurities. This multi-functional approach replaces what would traditionally require multiple separate purification steps, reducing energy consumption while maintaining high purity.

The patent extracts harmful impurities (maleic acid, maleic anhydride, protoanemonin) from the production process using selective adsorption. This ensures that only high-purity (meth)acrylic acid enters the polymerization step, preventing impurity-induced chain termination and transfer reactions while maintaining high production rates.

The patent performs preliminary purification and impurity removal before the polymerization step. By pre-treating the (meth)acrylic acid stream to eliminate harmful impurities through adsorption, the subsequent polymerization process proceeds reliably without unwanted side reactions, ensuring both high productivity and polymer quality.