Efficient Conversion Of Furan Into Benzoic Acid In Ionic Liquids

With the rapid development of the economy and the rapid expansion of the population,a global energy crisis has been triggered.Traditional fossil resources are indispensable for human development,but their large-scale exploitation makes environmental pollution and ecological damage increasingly prominent.Biomass,a renewable resource in the form of the only organic carbon on Earth,can reduce human dependence on fossil resources and reduce environmental load.Therefore,the development of clean renewable biomass conversion to make fine chemicals and energy molecules has become a hot research topic at home and abroad.Among many aromatic compounds,benzoic acid is widely used in daily life and industrial production.Currently,industrial toluene oxidation to produce benzoic acid has problems such as catalyst deactivation at high temperature,complicated preparation process,and non-renewable product.Hence,this paper aims to explore a highly efficient and stable catalytic system to the conversion of furan and acrylic acid to bio-based benzoic acid.In this paper,direct synthesis of bio-based benzoic acid via by a remarkable synergism of dual-acid?Lewis-Br?nsted?catalysts in hydrophobic ionic liquid.ZnCl₂-H₂SO₄+[Emim]NTf₂ was screened as the optimum catalytic system,and the furan conversion and benzoic acid yield were 99.4%and 80.7%,respectively.[Emim]NTf₂as a solvent can effectively accelerate the reaction and enhance the yield of benzoic acid.Combined with GC-MS,the possible reaction mechanism and related substrate expansion studies were carried out.The yield of methyl benzoate reached 69.2%when the dienophile methyl acrylate reacts with furan.Although the preparation of benzoic acid was obtained under atmospheric pressure,the recyclability of the catalyst cannot be achieved,which further limited the application.In this paper,“one-pot”synthesis of furan to bio-based benzoic acid using Br?nsted acidic ionic liquid was conducted.The acidity strength of different Br?nsted ionic liquids was calculated by the Hammett equation.The results indicated that the acid strength of ionic liquid is positively correlated with the yield of benzoic acid.[BSO₃HMIm]HSO₄ was used as the optimum catalyst to obtain a moderate yield of benzoic acid.The activation energy of the reaction was calculated by reaction kinetics to be 72.7 KJ/mol.Through the comparison of two catalytic systems,we concluded that the design and development of ionic liquids with Lewis and Br?nsted dual-acid catalytic active sites or heterogeneous catalysts?such as molecular sieves?can achieve the economic cyclability of the catalysts.In summary,the main work of this paper is to explore two catalytic systems to achieve efficient conversion of biomass furan derivatives to benzoic acid.It provides a new route and platform for the preparation of renewable aromatic compounds,laying a theoretical and engineering foundation for industrial production.