Study On The Synthesis Of γ-Butyrolactone And 2-Methylfuran Through The Coupling Process

There are many deficiencies existing in the conventional individual dehydrogenation of 1,4-butanediol and hydrogenation of furfural, such as poor hydrogen utilization, hardly controlled reaction temperature, and low selectivity to desired products. In order to solve these problems, a novel coupling process of the dehydrogenation of 1,4-butanediol and the hydrogenation of furfural has been invented for the synthesis of y-butyrolactone and 2-methylfuran simultaneously by Zhu Yulei. In this coupling process, the heat released by the hydrogenation of furfural can be used for the dehydrogenation of 1,4-butanediol, and the H2 released by the dehydrogenation of 1,4-butanediol can be utilized by the hydrogenation of furfural, leading to much easier temperature control and more perfect hydrogen mass balance (with hydrogen recycle but no hydrogen supply and release). However, a full understanding of the process and the mechanism for this reaction is still lacking. Thus the detailed study of this coupling process shows great interest. In this paper, the coupling process is studied further in term of reaction and catalyst. The results and corresponding conclusion obtained in this work are summarized as follow:1. The dehydrogenation of 1,4-butanediol and the hydrogenation of furfural over the Cu-Cr catalysts are studied in detail respectively and the proper reaction conditions of the two reactions are achieved. The XRD and TG-DTG characterization results show that Cu?is the active site of reaction, and the presence of Cr is in favor of high dispersion of Cu, which results in increasing of the reaction activity and selectivity. The reduction temperature is lowed by the addition of calcium and barium promoters, leading to an increased yield of the desired products.2. Over a Cu-Cr-Ca-Ba catalyst with excellent dehydrogenation and hydrogenation performance, the coupling process is investigated in detail, and the proper reaction conditions are achieved.3. A series of Cu-Zn-Al catalysts are prepared by using different aluminium compounds, and the performance of them is studied through the coupling process.The results show that the Cu-Zn-Al catalyst which prepared by alumina gel has the better reaction performance. The effect of calcination temperatures on this optimal catalyst is investigated in detail, and the results show that the suitable calcination temperature for Cu-Zn-Al catalyst is about 350癈. Lower temperature cannot facilitate the precursor to complete decomposition and higher calcination temperature will decline the surface area of the catalyst, which finally declines the yield for desired products.4. The experimental results show that the specific activities for 1,4-butanediol and furfural conversion are improved at high temperature, but the simultaneous loss of surface area offsets the gain in specific activity and final causes the decline in the overall activity of catalyst.