Studies On Luffa Cylindrical Sponge Char Sulfonic Acid Catalyst Preparation And Its Application

Char sulfonic acid (C-SO3H) catalyst is a new type of carbon based solid acid catalysts.It has characters of high catalytic activity, easy separation, good stability, and be friendly forenvironment and society. Generally, there were two kinds of methods for preparing C-SO3H.One is incomplete carbonization of aryl sulfonic acid compounds; another is prepared fromsaccharides and biomass by incomplete carbonization followed by sulfonation. Since glucose,cellulose, starch were successfully prepared for char sulfonic acid catalyst, the bio waste wasused for material of char sulfonic acid catalyst, such as peanut shells, corn straw, hickory hull.These C-SO3H catalyst has effect on hydrolysis, esterification, and transesterificationreactions.Due to the high cellulose content of82.4%, Luffa cylindrical sponge is a good carbonsource for preparing the C-SO3H catalyst. In this paper, we firstly prepared the LuffaCylindrical sponge char sulfonic acid (LC-SO3H) catalyst by the carbonization at300℃for3h, then sulfonation at90℃3h. The neutralization titration and EA gave acidity of1.119mmol/g. XRD pattern and Raman spectra indicated LC-SO3H as an amorphous solid.The surface areas of the catalyst determined using the BET is mesoporous. The dispersed rodlike structure and high porosity of the catalyst were clearly seen in SEM images. Thecharacteristic bands for S=O and–SO3H were clearly visible in the FT-IR spectra. The spectraof TG-DTA indicated that excellent thermal stability between100℃and200℃.The catalytic properties of LC-SO3H catalyst were investigated using orthogonalexperiment design in the synthesis of furfural from the xylose. The stability and recycle timeswere also studied. The optimum reaction conditions were as follows:2h reaction time,200℃reaction temperature,10wt%catalyst, the furfural yield reached78.69%. The catalystperformance dropped after the first run, which may attribute to a loss in the amount ofsulfonic acid groups on the surface of the catalyst. The catalyst can be used repeatedly, withlittle change of catalytic activity. Furthermore, the activities of used catalysts can be fullyrestored if they were resulfonated.The optimum extraction conditions of furfural from hickory hull via a two-stage processwere evaluated by Box-Behnken central composite experimental design and response surfacemethodology analysis. The optimum conditions for extraction yield of xylose were as follows:3h reaction time,120℃reaction temperature, dilute sulphuric acid to hickory hull ration of25. Under the optimum conditions, the extraction yield of xylose reached0.1633g/g, which was consistent with the estimated value,0.165609g/g. Then the hydrolytic reaction of xyloseto furfural with LC-SO3H catalyst was studied, the furfural yield can reach15.74%. Theexperimental results indicated that acidity of catalyst was positively related to the yield offurfural.The catalytic properties of LC-SO3H catalyst were also investigated using orthogonalexperiment design in the synthesis of epoxidized soybean oil (ESO). The influences ofhydrogen peroxide, formic acid, catalyst, reaction temperature and reaction time on epoxycontent were investigated. The optimum conditions were as follows:65℃reactiontemperature,3h reaction time,24mL formic acid dosage,3.2mL hydrogen peroxide dosage,0.7g catalyst. Under the optional conditions, the epoxy content is greater than6.5%. Thepresence of new peaks in the FT-IR spectra of ESO at1162cm-1,3007cm-1，attributed to theepoxy group indicated that soybean oil had been transformed into the epoxidized soybean oil.This synthesis method of epoxidized soybean oil with LC-SO3H catalyst had no pollution tothe environment.