Preparation Of 1,3 - Propanediol By Catalytic Hydrogenation Of Methyl 3 - Hydroxypropionate

Being widely used as a good solvent, protective agent and antifreeze agent,1,3-propanediol(1,3-PDO) has also perfect wettability and bactericidal activity. As an important chemical intermediate, a wide variety of high molecular materials such as polyester, polyether, polyurethane fiber and so on, with special or advanced function-alities can be readily produced from1,3-PDO. Currently, the way for1,3-PDOpreparation is manily categoritized as chemical and biological methods, with the former one being frequently practiced. However, the demanding reaction conditions of the conventional chemical methods have greatly limited theircommercialization. From both technological and economic points of view, the catalytic hydrogenation of3-hydroxyl propionic acid methyl ester (3-HMP) to prepare1,3-PDO is highly attractive in terms of the mild and practical operation. Against this background, the present study is focused on the exploration of new copper-based catalysts capable of efficient3-HPME hydrogenation to furnish1,3-PDO.Compared with other hydrogenation of esters, the β-hydroxyl of3-HPME is very easily dedydrated to form water, and this will lead to the undesired formation of by-products, such as saturated esters and monohydric alcohol. The centralissue to the present study is to develop a vable catalyst to supress secondary reactions. Based onan initial stage of the Cu/SiO2catalyst screening, the preparation conditions have been optimized as using copper nitrate as copper source, coprecipitation as preparation method, silica as support, a two-step calcination, reduction under300℃and Cu loading is70wt%. It was also established that the overall catalytical performance can be further improved by adding Mn and Zn as additives, which constitutes a solid basis for practical application. Finally, the reaction conditions were optimized, the conversion of3-HPM and yields can be99.8%and82.7%accordingly under the conditions that reaction temperature is160℃, pressure is7Mpa, and the ratio of reactant to solvent and hydrogen to ester are1:10and27respectively.Meanwhile,The effects of the catalyst morphology, active component and loading on the activity of our catalyst had been investigated from the characterization of XRD、 SEM、TEM、TPR、BET and In-situ DRIFTS. We got that high dispersion and small particle size of active component will be benefit to the reaction activity. What’s more, the reaction of hydrogenation of3-HPM to synthesis1,3-PDO is influenced by both Cu0and Cu+, a suitable ratio of Cu0and Cu+afford us the best catalyst stability, activity and selectivity.