Selective Hydrolysis of Cellulose and Polysaccharides into Sugars by Catalytic Hydrothermal Method Using Sulfonated Activated-carbon

Abstract

Mildly hydrothermal reaction using solid acid catalysts for cellulose hydrolysis into glucose has potential abilities to be one of the key technologies for a future sustainable society using cellulose biomass. Among the solid acid catalysts tested, such as H-form zeolite catalysts and sulfated and sulfonated catalysts, sulfonated activatedcarbon (AC _ SO3H) catalyst showed remarkably high yield of glucose in the hydrolysis of cellulose with β-1,4-glycosidic bonds under hydrothermal conditions at temperatures around 423 K. The AC _ SO3H catalyst with hydrothermal pre-treatment had excellent catalytic properties attributed to the high hydrothermal stability and the strong acid sites of the sulfo functional groups and the activated carbon surfaces for polysaccharide adsorption. A bifunctional sulfonated activated-carbon supported platinum (Pt/AC _ SO3H) was prepared by impregnation of platinum on activated carbon (AC) and sulfonation of the prepared Pt/AC. Gluconic acid was produced from polysaccharides, such as starch and cellobiose, in water at 393 K under air by a one-pot process using the Pt/AC _ SO3H catalyst.

Is Selective Heating of the Sulfonic Acid Catalyst AC-SO3H by Microwave Radiation Crucial in the Acid Hydrolysis of Cellulose to Glucose in Aqueous Media?

“…Contrary to the microwave methods employed in the present study that produced glucose in 55% yields on irradiation for 30 min at a temperature of 200 • C, the yield of glucose from the acid hydrolysis of cellulose in the presence of AC-SO 3 H catalyst particulates subjected to conventional heating at 150 • C in the steel autoclave was only 40.5% after 24 h, and 44% when heating for 3 h at 180 • C [19,20]. Clearly, there are obvious advantages in the use of microwave heating methods for which the shortening of reaction time is an effective feature.…”

“…The earlier study of the acid hydrolysis of cellulose with AC-SO3H catalyst treated the cellulose by the ball mill technique followed by heating in a steel autoclave at 150 °C for 24 h with agitation (22 rpm) [19,20]. In the present study, microcrystalline cellulose powders (K.K.…”

“…Onda and coworkers [19,20] reported that there was little, if any, decrease of catalyst activity in the acid hydrolysis of cellulose carried out by conventional heating in a steel autoclave reactor in the presence of AC-SO3H catalyst particulates when the latter were recycled no less than three times. Their observation was confirmed in the present study upon recycling the microwave-heated catalyst used in either reactors (Pyrex glass and SiC); no decrease in reaction efficiency occurred when the catalyst particulates were used a second time.…”

“…The AC-SO3H solid catalyst powder was prepared using the method reported by Onda and coworkers [19,20] and by Toda et al [23]. Typically, activated carbon particles (Wako Pure Chemical Industries Ltd., Osaka, Japan; average diameter, 0.05 cm; 1.0 g) are added to concentrated H2SO4 (Wako Pure Chemical Industries Ltd., Osaka, Japan; 20 mL) and subsequently heated under a flow of Ar gas at 150 °C for 16 h. The resulting sulfonated-activated carbon material was washed repeatedly using hot distilled water (3 L; 80 °C), and subsequently treated hydrothermally at 200 °C for 3 h followed by repeated washings with hot distilled water until sulfate ions are no longer detected in the filtrate.…”

Lignosulfonate-based heterogeneous sulfonic acid catalyst for hydrolyzing glycosidic bonds of polysaccharides

“…Acid and enzyme are among the most common catalysts for hydrolyzing cellulose into glucose [10,11]. In recent years, recyclable solid acids for cellulose hydrolysis have attracted great attentions [12][13][14][15][16][17][18][19][20][21]. However, achieving high selectivity and activity still remains a challenging task.…”