Study On The Reacting Rule Of Furfural Product From Corncob By Toluene/Water Two-phase Method

With the global energy shortage, furfural as a platform was used to produce fuelsget more and more people’s attention. however, China’s industrial production offurfural that use pollute environment to get little economic benefits has yield lowly,waste water\gas\residuals etc. problems. In this paper, to solve these problems, corncob was used as the raw material and sulfuric acid was used as catalyst to study thetoluene/water two-phase method for the production of furfural.The effect of water,acids, reaction time and temperature to furfural yield and component of the solidphase was mainly researched. As well as the organic product of furfural waspreliminary hydrotreating.Firstly,in order to achieve the full use of polymeric sugars, choose the ratio ofwater to corncob under7g/g, the acid feed ratio of10.5~24.5wt%, the reactiontemperature of100~180℃as the reaction conditions.Do our best to make thecellulose and hemicellulose of corn cob were catalyzed hydrolysis and produce furancompounds (5-(hydroxymethyl) furfural, furfural, etc.) in the same reactor. Theresult was that: the toluene has no effect to furfural yield and the degradation ofcellulose and hemicellulose, but water can facilitate the degradation of hemicelluloseinto monosaccharides such as pentoses, however under no-acid conditions, theamount of furfural was less; When temperature is greater than160℃, the acid feedratio of17.5wt%, the ratio of water of7g/g, oil ratio of12mlg, it is possible to makethe cellulose and hemicellulose degradation entirely, but when the yield of furfuralreached the highest value of16.9%, the5-(hydroxymethyl) furfural and the amountof levulinic acid were rarely.When cellulose hydrolysis to glucose and other simplesugars, some of glucose decomposition became to C5or C5-small organic molecules,and others was further dehydrated to form5-(hydroxymethyl) furfural, but the5-(hydroxymethyl) furfural and very unstable, in addition to generating a small amountof levulinic acid, most of it will generate polymerization occurs coking byproducts.Overall, in one reactor, it is difficult to obtain a large amount of5-hydroxymethylfurfural when the furfural yield is the highest value. Next we consider only make the corncob hemicellulose into furfural,while thecellulose remain in solid phase. Product furfural at atmospheric pressure and toluenereflux temperature (about103℃),when soaking for12h,the reaction time was2.5h,the furfural yield compared with the previous maximum was drastically decreased（about12%）. It is indicate a lower reaction temperature, longer reaction time, theyield will decrease. Reducing the acid feed ratio, the ratio of water in a closed reactorto study the hydrolysis of hemicellulose,the results show that when the reactiontemperature was160℃,acid feed ratio of2wt%,the ratio of water to0.5g/g,hemicellulose can be converted completely,furfural yield of reached16%, while theamount of cellulose loss is only about7%. In conclusion, we reduce the amount ofwater from7g/g to0.5g/g, which was reduced14times, as well as the amount of acidis reduced from17.5wt%to2wt%,which was reduced almost9times, not only toensure a higher yield of furfural, but also to avoid the large number decomposition ofcellulose,and compared the residue image,we found that the shallower of furfuralresidue of color, the more content of cellulose.Finally,this paper analyzed that the effect of initial concentration of standardtoluene furfural solution, reaction time, reaction temperature and the amount ofhydrogenation catalyst to furfural. The results showed that we chooseCuO-ZnO-Al2O3as the catalyst and the reaction conditions as follows: reactiontemperature170℃,reaction time2h, the hydrogen pressure is4Mpa,catalyst andfurfural ratio1:3(g/g), the furfural which was obtained in the first step can beconversion absolutely,and the alcohol yield was about94%,the small organicmolecules C5-has little effect on the hydrogenation catalyst and the conversion yieldof furfural alcohol.On this basis,we propose a conceptual flow chart of corncob utilization,andmake the material and energy balance of furfural from biomass and refining.Theresult is that1t furfural will consume about6t corncobs and power supply is7.48Gcal(Aspen plus simulated value is6.75Gcal under ideal conditions).We find that energyconsumption reduced more than50%compared with the existing factories whichconsumed15~19Gcal of1t furfural.