多元醇一步法制备高碳烃液体燃料的研究

在较温和的条件下,山梨醇和木糖醇被氢碘酸还原转化为高碳烃液体燃料。产物采用GC-MS和FT-IR进行定量分析与表征,并对高碳烃产品的理化性质进行了测定。结果表明,以山梨醇为原料制备的高碳烃产物主要是包括C12H16、C12H18、C12H20、C12H22和C18H26在内的烷烃、烯烃和芳香烃等化合物,烃类的总产率可达85.1%。以木糖醇为原料的反应过程与山梨醇相似,但所得高碳烃是以C10和C15为主的烃类化合物,产率为62.8%。实验还以质量分数为50%的山梨醇和50%的木糖醇混合物为原料制备了高碳烃,结果发现,产物中除C10、C12、C15和C18烃外,还有一定量的C11烃生成,高碳烃产率为65.4%。反应产物经碱化、旋转蒸发和减压蒸馏后分离得到纯度较高的高碳烃,其含水量低于0.2%,常温下运动黏度为3.15~3.17 mm2/s,密度为0.830~0.840 g/mL,含氧量为1.8%~2.1%,热值高于43 MJ/kg。高碳烃的生成是由于多元醇被还原过程中C-I键的极性反转和分子间C-C键的偶联导致。

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.