Design And Synthesis Of Bio-based Straight-chain Alkane C₄₉H₁₀₀

Due to the unique molecular structure,long-straight-chain alkanes（especially those with more than 40 carbons）have been widely used in basic scientific research,material processing,electronic machinery,defense aviation and other fields,and have high scientific and economic value.In current industrial production,the synthesis routes of long-chain alkanes mainly include Fischer-Tropsch process,ethylene polymerization and polyethylene cracking.However,the alkanes produced are all mixtures,and high-energy rectification is required to separate and obtain pure long-chain alkanes.However,the structure of bio-based long-chain alkanes are controllable and the carbon chain length is uniform,so the synthesis of long-chain alkanes from bio-based compounds is a very competitive strategy.Based on the existing work foundation of the research group,the biomass platform molecules acetone,furfural and fatty acid anhydride or acyl chloride were accurately assembled through a simple four-step catalytic reaction of aldol condensation,selective hydrogenation,Friedel-Crafts acylation and hydrodeoxygenation to C₄₉H₁₀₀ linear alkanes in this paper.The main research contents of this paper are:Taking the biomass-derived chemical C₃ acetone as the central carbon source,the initial extension of the carbon chain is achieved by the aldol condensation reaction between C₅ furfural and C₃ acetone under the solid base Mg O catalyst,and C₁₃ difurfurylidene acetone（F₂Ac）is efficiently generated.Since the strong conjugation effect between the C=C bond on the carbonyl chain and the C=C bond on the furan ring of F₂Ac,the electron density at the 2-position is reduced,which reduces the probability of F₂Ac directly acylating with fatty acid anhydride.Therefore,we selectively hydrogenated the C=C bond of F₂Ac on the supported Cu/Si O₂-HT catalyst to break the conjugation effect to synthesize C₁₃ ketone.Subsequently,under the catalysis of solid acid P/Si O₂,the acylation of both sides of the furan ring between the acetic anhydride and C₁₃ ketone is achieved;and as the carbon number of fatty acid anhydride increases,the steric hindrance gradually increases,and it becomes difficult to extend the C-C bond in the acylation reaction catalyzed by P/Si O₂.The C₄₉ precursor can be synthesized by Friedel-Crafts acylation with stearyl chloride under the catalysis of Al Cl₃.Finally,the hydrodeoxygenation of C₁₇～C₄₉ precursors under the catalysis of bifunctional metal/acid Pd/Nb₂O₅ catalyst is carried out,effectively suppressing carbon chain breakage in the process,and ultimately obtaining structurally controllable long-chain alkanes C₁₇H₃₆…C₄₉H₁₀₀ with a single carbon chain length.This paper provides a new route for the synthesis of bio-based long-chain alkanes.