Preparation of liquid hydrocarbon fuels from polyols via one-step redox process

Sorbitol and xylitol were used as raw materials for the preparation of heavier hydrocarbons by reduction with hydriodic acid under mild reaction conditions. The generated liquid hydrocarbons were analyzed by gas chromatography-mass spectrometry (GC-MS) and Fourier transform infrared spectroscopy (FT-IR). Their physicochemical properties were further characterized. The heavier hydrocarbons obtained from sorbitol mainly include C₁₂H₁₆, C₁₂H₁₈, C₁₂H₂₀, C₁₂H₂₂ and C₁₈H₂₆, with a yield of 85.1%. In contrast, that prepared from xylitol were mainly composed of C₁₀ and C₁₅ hydrocarbons with a yield of 62.8%. When using a mixture of sorbitol/xylitol (50:50) as feedstock, C₁₁ hydrocarbons were also generated besides C₁₀,C₁₂,C₁₅ and C₁₈ hydrocarbons. The yield of total heavier hydrocarbons was 65.4%. To get purer liquid hydrocarbons, the obtained raw product was treated with potassium hydroxide in an ethyl alcohol solution, followed by rotary evaporation and vacuum distillation, and a liquid hydrocarbon fuel contains less than 0.2% of water and 1.8%~2.1% of oxygen was generated. Its kinematic viscosity is 3.15~ 3.17 mm²/s, density 0.83~ 0.84 g/mL, and calorific value greater than 43 MJ/kg at room temperature. The umpolung of the C-I bond and the intermolecular C-C coupling may result in the formation of heavier hydrocarbons from polyols.