Production And Separation Of5-HMF’S Acetalization Product

With the development of modern society, energy issue has become more and more serious. It will affect the security of our country, stability of our society and future of all humanbeings. So scientists throughout the world are focusing on looking for a kind of sustainable fuel resources to replace the fossil fuel we are using today, hoping that the problem of lacking energy will be relieved. This dissertation will research on the synthesis and separation of compounds HDMF and DMMF starting from bio-material platform product5-HMF, because the two compounds can be applied as bio-fuel.First, we focus on the analysis condition for the product before anaysis, including the column, the mobile phase and their ratio, the flow, and the absorption wavelength, et al. And we’ve found that when MeOH/H2O is20/80、flow1.0ml/min、wavelength240nm, column temperature (20±5)℃, injection20μl, the analysis condition is good.For the qualitative analysis of5-HMF on HPLC, we can determine the peak by injecting the pure compound we bought. For the quantitative analysis of5-HMF, we also used the pure compound to make a calibration curve. While for the qualitative analysis of HDMF on HPLC., we used a method of observation of peak’s change under different temperature combined with GC-MS. For the quantitative analysis of HDMF, we used the compound we purified beforehand to make a calibration curve. And for DMMF’s analysis, we used the method of area proportion with HDMF to see roughly how DMMF changes under different condition.Then we select the best solvent for the separation. We have found that the1:3ratio of acetic ether/n-hexane is a good choice for seperating HDMF, while the1:5ratio of acetic ether/n-hexane is a good for seperating DMMF.We immersed the silica gel in nitric acid for a while to form a new acid catalyst(we call it Si-OH(HNO3) for short), which can catalyze the acetalization reaction. We selected the nitric acid immersed silica gel catalyst as the best from three common catalysts for the acetalization reaction because its acidity is neither too strong or too weak.Then we have found that, the condition of60℃,1h is best for HDMF and the condition of140℃,2h is best for DMMF.We’ve also found that the PH of the mixed solution have a great influence on the result of analysis even though the reaction has ended. However, when the solution is neutralized, the conversion and yield hardly changed. At the best condition, we synthesized HDMF. With the hand-made seperating column filled with sillica gel, we seperated HDMF from the mixed product successfully, using1:3acetic ether/n-hexane as developing solvent. The analysis of GC-MS and1HNMR shows that the purity of the separated HDMF is good.Also, we try to synthesis HDMF directly from fructose. Even though the conversion of fructose is quite good, the yield of HMF and HDMF is not very high. This is because fructose’s selectivity to HMF is not high, thus HDMF’s yield is not good either. We suggest that DMSO should be added to the system to improve fructose’s selectivity to HMF. In this way, the one-pot reaction from fructose should be possible.