Experimental studies for levulinic acid production from diosgenin solid waste.

【Objective】 The studies were carried out to explore the conditions of levulinic acid from diosgenin solid waste.【Method】 By using single factor experiment method,the acid catalysis was used to detect the effects of catalytic acid,acid volume fraction,reaction temperature,reaction time,liquid-solid ratio and granularity on levulinic acid production from diosgenin solid waste at atmospheric pressure.Based on this,response surface experiments design by Box-Behnken of four factors and three levels was conducted to obtain the optimized process conditions.The four factors were sulfuric acid volume fraction,reaction time,liquid-solid ratio and granularity.【Result】 Single factor experiment indicated that the maximum yield of 18.31% levulinic acid was achieved at 4% sulfuric acid volume fraction,12∶1 of liquid-solid ratio,10 h of reaction time and 0.84 mm of granularity in 100 ℃ water-bath temperature.Data fitting of multiple factor experiment indicated that theoretical yield of 20.67% was obtained at 4.5% sulfuric acid volume fraction,18∶1 of liquid-solid ratio,12.5 h of reaction time and 0.25 mm of granularity in 100 ℃ water-bath temperature.【Conclusion】 Sulfuric acid volume fraction,reactive time and liquid-solid ratio were main factors for hydrolysis of diosgenin solid waste,and the granularity in the range of 0.15-0.84 mm had little influence.