Preparation of porous macromolecule oxazine poly-ionic liquid solid acid catalyst and its application in an esterification reaction

Background Chinese research on citrate is typically into plasticizer alternatives to the carcinogenic phthalate (PAEs) plasticizers. PAEs plasticizers can induce obesity and metabolic disorders, whereas citric acid vinegar plasticizers have the advantages of low biological toxicity and environmental friendliness. Results Novel porous macromolecule oxazine poly-ionic liquid solid acid catalysts were prepared and characterized by scanning electron microscopy (SEM), Brunner-Emmet-Teller(BET) measurements, Fourier transform infrared spectroscopy (FTIR), energy dispersive spectrometer (EDS) and thermogravimetric analysis (TGA). Characterization results showed that the synthesized catalyst was a porous polymer with good heat stability. The catalytic performance of the catalyst was evaluated by synthesis of tributyl citrate from citric acid and n-butanol. Conclusion The optimal reaction conditions were determined as 9% (wt%) citrate mass. The experimental results showed that the optimal reaction conditions were determined as amount of catalyst 9% (wt% citrate mass), 150 degrees C reaction temperature, 3.5 h reaction time and 1:3 ratio of citric acid and n-butanol. Under optimal conditions, the conversion rate of citrate acid was <= 91.74%. The catalytic activity did not reduce obviously after being reused for ten times. Then, the reaction conditions were fited by the surface optimization method. The fitted optimum conditions were as follows: 8.881% amount of catalyst (mass of citric acid), 148.259 degrees C reaction temperature, 3.331 h reaction time, 1:2.958 citric acid:n-butanol ratio; this gave a conversion rate of citric acid of <= 92.998%. The simulation results are in good agreement with the experimental results. (c) 2022 Society of Chemical Industry (SCI).

Automated summary

This study focuses on the synthesis of tributyl citrate using a novel solid acid catalyst and evaluates its catalytic performance. The optimal reaction conditions were determined to be 9% (wt%) citrate mass, resulting in a conversion rate of citric acid of <= 91.74%. The catalytic activity of the catalyst remained stable even after multiple reuse. The fitted optimum conditions obtained through surface optimization were in good agreement with the experimental results.