Preparation Of Xylo-oligosaccharides And Xylitol From Bamboo Shoot Shell Xylan On The Solid Acid Catalyst

Bamboo shoot shell was as the raw material in this study,the experiment use NaOH-H2O2 extraction after bamboo shoot shell was treated.Effects of extraction temperature,ratio of solid to liquid,extraction time,alkali concentration and alkaline concentration of H2O2 on yield of xylan were analyzed.The optimal alkali extraction conditions for the preparation of the xylan were 2 g cellulose,solid-liquid ratio 1:25,the mixed solution of 2% H2O2 and 15% NaOH,reaction time 10 h at 35?,xylan yield could reach 32.75%.And using FT-IR techniques to study xylan obtained.The results showed that,the alkali soluble xylan of Bamboo shoot shell is xylanase mainly composed of ?-xylose as the main chain and arabinose as the branched chain,contained a small amount of 4-O-methyl-D-glucuronic acid.In the paper,xylo-oligosaccharides?XOS?were prducted by solid-acid catalytic hydrolysis of xylan.Xylitol were prepared by one-pot selective conversion of xylan under mild conditions.Effects of amberlyst-15 amount,temperature and reaction time on the yield of XOS and conversion of xylan and reaction time,temperature,H2 pressure,the amount of Pd/C and amberlyst-15 on the yield of xylitol were investigated.The results showed that the optimal conditions for the preparation of xylo-oligosaccharides by xylan hydrolysis were as follows: xylan 0.5 g,amberlyst-15 0.3 g,reaction time 3 h at 110?.Under this condition,The yield of XOS was 41.97%.the optimal conditions were0.5 g xylan,0.2 g amberlyst-15,0.15 g Pd/C,5 MPa H2,reaction time 1 h at 140?.xylitol yield was69.93%.Pinus massoniana Lamb and Cunninghamia lanceolata were used as raw materials to prepared Pinus massoniana Lamb active carbon and Cunninghamia lanceolata active carbon.Biomass carbon based sulfonated solid acid?AC-SO₃ H,M-AC-SO₃ H and S-AC-SO₃H?was prepared by sulfonation method with active carbon,Pinus massoniana Lamb active carbon and Cunninghamia lanceolata active carbon as the carrier,and the effects of different carbon based solid acid catalysts on the yield of xylooligosaccharides were investigated.The AC-SO₃ H showed better catalytic performance.The effects of the amount of AC-SO₃ H,reaction temperature and reaction time on the yield of xylo-oligosaccharides and each componentwere studied,The optimal conditions were determined by orthogonal experiments are as follows: xylan 0.5 g,AC-SO₃ H catalyst 0.2 g,reaction temperature 140,time 3 h.The largest yield of Xylo-oligosaccharides was 66.60% in the hydrolysis of xylan.The catalysts AC-SO₃ H and S-AC-SO₃ H were characterized by FT-IR,XRD,BET,SEM and TGA.The FT-IR spectrum showed that the-SO₃ H does exist in the catalyst.The XRD and SEM showed that the catalyst was a turbostratic carbon structure made up of irregular particles with a diameter of several microns.The BET showed that the-SO₃ H can be adsorbed on the surface and the pore of the catalyst.The TGA indicates that the catalyst has a stable catalytic performance at about 200?.