Preparation Of Zirconium-based Catalyst And Its Application In The Preparation Of γ-valerolactone From Furfural

With the deterioration of the environment and the exhaustion of fossil energy,the use of abundant and renewable biomass energy to produce liquid fuels and value-added chemicals has become an important research content in the field of green chemistry.Platform compounds derived from biomass,such as furfuryl alcohol(FA),ethyl levulinate(EL),andγ-valerolactone(GVL)have great development potential.Among them,FA can be used in resins,pesticides,polymer intermediates and fine chemicals,EL can be used as flavoring agents,fragrances,herbicides and pharmaceutical intermediates,and GVL can be used as green solvents and fuel additives.In order to efficiently prepare FA,EL and GVL,it is very important to design efficient and stable catalysts.For this reason,this thesis mainly designed three different zirconium-based catalysts for the transfer hydrogenation of furfural(FF)to FA,FA alcoholysis to generate EL,and the reaction of EL to GVL by hydroesterification.The specific research content is as follows:(1)The zirconium isophthalate-5-sulfonate catalysts(Zr-SA-x)in different proportions were synthesized by the co-precipitation method for the reaction of FF catalytic transfer hydrogenation(CTH)to prepare FA,and the catalysts were characterized.Subsequently,the reaction temperature and time,the amount of catalyst,the hydrogen donor and the type of catalyst were explored.The results showed that under the conditions of 120 ~oC,2 h,5 m L isopropanol,1 mmol FF,and 0.10 g Zr-SA-3,98.39%FF conversion and 95.35%FA yield could be obtained.Afterwards,the heterogeneity and reusability of Zr-SA-3 were explored,and it was found that Zr-SA-3 has good heterogeneity and there was no significant loss of activity after being reused for five times.Finally,the reasons for the high activity of the Zr-SA-3 were analyzed,and the possible reaction mechanism was proposed in combination with the poisoning experiment.(2)Zirconium dodecyl benzene sulfonate(Zr-DBS)and zirconium dodecyl sulfate(Zr-DS)catalysts were synthesized by a simple co-precipitation method,subsequently,a series of characterizations were performed on them,and the structural performance characteristics were explored.Zr-DBS and Zr-DS were used in the FA alcoholysis reaction to generate EL and it was found that Zr-DBS has higher activity.By optimizing the reaction parameters,it was obtained that the reaction was carried out under optimal conditions(150 ~oC,2 h,10 m L ethanol,1 mmol FA,0.20 g Zr-DBS),and 98.83%FA conversion and 95.27%EL yield were obtained.Subsequently,when Zr-DBS was used to catalyze the reaction of other alcohols with FA to prepare the corresponding alkyl levulinate,it was found that it still had high catalytic activity.At the same time,the leaching experiment showed that the catalyst is a heterogeneous catalyst,and the cycle experiment shows that there was no obvious loss of activity after Zr-DBS was reused for four times.Subsequently,the reasons for the high activity of Zr-DBS were analyzed.Finally,on the basis of previous reports,a possible catalytic reaction mechanism was deduced.(3)The zirconium gallate catalysts(Zr-GA-x)with different ratios were synthesized by co-precipitation method for the reaction of EL catalytic transfer hydrogenation and esterification to prepare GVL and the catalysts were characterized.Subsequently,the type and dosage of catalyst,the reaction temperature and time of the experiment were optimized,and the reaction was carried out under the optimal reaction conditions(160 ~oC,8 h,5 m L isopropanol,1 mmol EL as substrate,0.20 g Zr-GA-2),98.58%EL conversion and 94.23%GVL yield were obtained as well.Leaching test and reusing experiments show that Zr-GA-2 has excellent heterogeneity and there was no significant loss of activity after being reused for six times.Subsequently,levulinic acid,methyl levulinate and butyl levulinate were used as substrates,and it was found that Zr-GA-2 still has excellent catalytic activity.Finally,the reason for the high activity of the Zr-GA-2 was analyzed,and a possible reaction mechanism was proposed in conjunction with the poisoning experiment.