Catalytic processes are important components of sustainable chemistry. We present a novel process to synthesize crotonic acid by sequential catalytic oxidation-condensation-oxidation reactions in a Soxhlet extractor. Oxidation of ethanol and crotonaldehyde is catalyzed by a new composite Cu/H₃PO₄ catalyst characterized by XRD (X-ray Diffraction), BET (Brunauer-Emmett-Teller analysis), TEM (Transmission Electron Microscopy), XPS (X-ray Photoelectron Spectrometry), and TG (Thermogravimetric analysis), showing higher activity and better stability compared to nano-copper, due to dispersion by a mutual support; external temperature compensation during the reaction allows ethanol oxidation without degradation of the catalyst. XRD and XPS analyses of the used catalyst reveal that monovalent copper is the active species for ethanol oxidation. The catalyst is effectively recovered and reused four times. Nano MgO catalyzes acetaldehyde condensation under mild conditions and can be recycled during the process. Conversion of ethanol is greater than 48%, and the selectivity to crotonic acid is 84% in the continuous process.

催化过程是可持续化学的重要组成部分。我们提出了一种新的过程，通过在索氏提取器中的顺序催化氧化-缩合-氧化反应来合成巴豆酸。新型复合Cu / H ₃ PO ₄催化乙醇和巴豆醛的氧化XRD（X射线衍射），BET（Brunauer-Emmett-Teller分析），TEM（透射电子显微镜），XPS（X射线光电子能谱）和TG（热重分析）表征的催化剂，显示出更高的活性和更好的稳定性与纳米铜相比，由于相互支撑而分散；反应期间的外部温度补偿使乙醇氧化而不会使催化剂降解。使用过的催化剂的XRD和XPS分析表明，一价铜是乙醇氧化的活性物种。催化剂被有效回收并重复使用了四次。纳米MgO在温和的条件下催化乙醛缩合，并且可以在此过程中循环使用。在连续过程中，乙醇的转化率大于48％，对巴豆酸的选择性为84％。