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Abstract
The catalytic hydrogenation of organic substrates containing many unsaturated functional groups is an important step in the industrial preparation of fine chemicals and has always been a hot spot in basic catalysis research. For example, the phenethyl alcohol obtained by the preferential hydrogenation of the C=O group of acetophenone is a valuable intermediate for the production of spices, flavors, and medicines. Furthermore, as the demand for 1-phenylethanol (PhE) continues to increase, the catalytic hydrogenation of acetophenone (AP) is becoming more and more important. The hydrogenation of acetophenone is a complex multi-step reaction. At present, relatively few catalytic systems are used in this reaction. The enantioselective hydrogenation on heterogeneous catalysts is due to its inherent operational and economic advantages, such as the atomic economy. It is one of the most ideal methods as it is easy to separate and recycle the catalyst. However, the traditional synthesis way in batch reactors usually takes a long time with an unsatisfying conversion which is not conducive to industrialization. Heterogeneous non-precious metal catalysts are advantageous for their implementation in flow reactor systems for industrial applications due to their ease of separation, low cost, and environmental protection. Herein, we report the first use of non-noble metal Ni-supported graphene-based catalysts for hydrogenation of acetophenone to phenylethanol with high efficiency in the flow reactor which can significantly improve mass and heat transfer. The conversion rate after optimizing the reaction conditions can be as high as 99.14% with a satisfactory conversion rate of 97.77%. This catalyst is magnetic and has good cyclability. After 48 hours of uninterrupted continuous experiments, the Ni-based catalyst still maintains high catalytic activity, the conversion rate still reaches 88.44%, and the catalyst structure remains intact and stable.
