Catalytic Synthesis of Geranyl Propionate

丙酸香叶酯的催化合成(英文)

[Objective] The aim was to explore the optimal conditions for the catalytic synthesis of geranyl propionate. [Method] The synthesis of mesoporous molecular sieves Al-MCM-41 was carried out in an open-vessel. The mesoporous structure of as-synthesized Al-MCM-41 was characterized by X-ray diffraction （XRD） pattern, Fourier transform infrared （FT-IR） spectrum, NH3-Temperature Programmed Desorption （TPD）, and N2 adsorption-desorption isotherms. The catalytic performances of Al-MCM-41 for the synthesis of geranyl propionate （GP） with geraniol and propionic acid as reagents also were investigated. [Result] The as-synthesized Al-MCM-41 possesses typical hexagonal mesoporous structure with high long-range order and crystalline degree. Based on the systematic investigation of reaction time, temperature, amount ratio of reagents and regeneration of catalyst, the optimum reaction conditions were obtained with molar ratio of geraniol to propionic acid of 1.0∶1.5, reaction temperature of 120 ℃ and reaction time of 8 h. The high GP selectivity of 70.01% with geraniol conversion of 40.01% was achieved under above optimum conditions. The catalyst inactivation can be observed after five catalytic cycles. The regeneration of inactivated catalyst with high activity and selectivity can be achieved by calcination treatment to remove the carbon deposition, which covers the acid site of catalyst. [Conclusion] The optimal conditions for the synthesis of geranyl propionate were obtained.

[目的]进行丙酸香叶酯的合成并优化合成条件。[方法]在敞开体系中合成中孔分子筛Al-MCM-41。通过X射线衍射(XRD)、红外光谱(FT-IR)、NH3程序升温脱附(NH3-TPD)、N2吸附-脱附和气相色谱(GC)等方法对所合成样品的结构和催化性能进行表征分析。用其催化合成丙酸香叶酯,考察了反应时间、反应温度、催化剂用量、反应物配比及催化剂再生对香叶醇酯化反应结果的影响。[结果]合成的样品具有中孔分子筛的六方介孔结构以及良好的长程有序性和结晶度,属于典型的中孔材料,分子筛表面有弱酸中心。最佳的反应条件是n(香叶醇)/n(丙酸)=1.0∶1.5,反应温度为120℃,反应时间为8h,但香叶醇的转化率仅为40.01%,丙酸香叶酯的选择性为70.01%。催化剂使用到第5次时有失活现象,可通过焙烧除去掩盖酸中心的积碳,使催化剂的活性和选择性得到恢复。[结论]得到了丙酸香叶酯的合成优化条件,为进一步研究奠定基础。