Study on Furfural Production from Hemicelluloses Bin Shen 1,a, Yanxue Liu 1,a,Yuxin Liu 1,a*, Jinhui Peng 1,a

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1 Advanced Materials Research Online: ISSN: , Vols , pp doi: / Trans Tech Publications, Switzerland Study on Furfural Production from Hemicelluloses Bin Shen 1,a, Yanxue Liu 1,a,Yuxin Liu 1,a*, Jinhui Peng 1,a 1 The Research Center of Pulp and Paper Engineering, Kunming University of Science and Technology, Kunming Yunnan province, , P.R. China *,a Corresponding author: iceberg-1212@163.com Keywords: Bagasse, Furfural, Sulfuric acid, Acetic acid Abastract. In this paper, furfural was produced from hemicelluloses of bagass by hydrolization reaction with sulfuric acid and acetic acid respectively. The effect of several variables such as temperature, liquid-to-solid ratio,time and catalyst charge(kcl) on furfural yield was studied. The results showed that the better yield of furfural was obtained in acetic acid hydrolysis system. However, compared to yield of acetic acid hydrolysis system, it need more time and higher temperature at the same liquid-to-solid ratio. At last, when sulfuric acid as catalyst, liquid-to-solid ratio was 1:6 and time was 5h at 150 C, furfural yield can reach 75 %. Introduction Furfural is a kind of important organic chemical raw materials and chemical solvents, widely used in petroleum refining, petrochemical, pharmaceutical and synthetic rubber industries[1], moreover, So far only by plant fiber source and exhaustion of fossil energy, the demand of furfural will steadily grow[2]. Therefore, furfural and furfural derivatives were produced by forestry and agricultural residues have being become more and more important. In currently, furfural Production Processes is divided into two steps[3]. The first-stage in the hydrolysis reaction is faster, slower second step dehydration-cyclization reaction. At present the majority of enterprises to take one step in the production, advantages of this method are less investment in equipment, easy to operate, but its low yield. Therefore,pentosan hydrolysis reaction and pentose dehydration-cyclization reaction in different reactor is becoming a new trend[4], especially prepared by mild acid hydrolysis furfural. At present, with corncob as raw material for producing furfural has been more mature. However, Hemicelluloses is a raw material for acid hydrolysis study of producing furfural is not yet widely. In this paper, Hemicelluloses of bagass acid hydrolysis process of the preparation of furfural conditions studied. The best process conditions were established and provide reference for production. Experimental Material. Bagasse was provided by a factory in Yunnan province. The hemicelluloses of bagasse was treated with sodium hydroxide, the specific process see the references [5]. Furfural Production from Hemicelluloses. The hemicelluloses of bagass, acid hydrolysis and the catalyst added to the reactor by a certain percentage to heating in the 120 r/min stirring speed. Waiting for reaction system to set temperature and heat preservation to the reaction end. The reaction liquid was filtered, separated and identified by aniline solution color reaction. Determation of furfural yield. Quantitative determination of furfural yield was performed by the references [6].The standard curve was also plotted according to this method. The egression equation of furfural yield (Y) and absorbance (X) was obtained, as follows: Y=0.1695X (R 2 =0.9993). All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, (ID: , Pennsylvania State University, University Park, USA-04/03/16,21:24:40)

2 Advanced Materials Research Vols Results and discussion Effect of furfural yield on the dehydrated temperature. From Fig.1 we can show that the reaction temperature is one of the main factors in the production of furfural. In the sulfuric acid reaction system (Fig.1(a)), when the temperature is 120 C, the yield of furfural was only 55.40%. However, the yield reached to 74.19% when the temperature rose to 150 C and the yield dropped to 62.3% when the temperature is 160 C. In the acetate hydrolysis System (Fig.1 (b)), it requires higher temperature under the same yield. In addition, the material gelatinization degree is smaller under the same temperature. By the dynamics of dehydration of xylose into furfural [7-8], the furfural synthesis reaction mainly is the dehydration of xylose into furfural at lower temperature, yet the furfural condensation reaction is significantly increased and the yield is rising with increasing reaction temperature. When the temperature is higher, it results in large amount of coke and the yield of furfural becomes low. Therefore, the temperature of acetic acid hydrolysis into furfural is 180 C. Fig. 1 Effect of furfural yield on the dehydrated temperature Effect of solid-liquid ratio on yield of furfural. Figure 2 (a) shows that the furfural yield reach to maximum when ratio of solid to liquid is 1:6. However, the furfural yield descends 10.3% when the solid-liquid ratio of 1:8. In Figure 2 (b), we get the same hydrolysis effect as sulfuric acid when the solid-liquid ratio of 1:8 and hemicelluloses will not appear the phenomenon of carbonization coking when using excess acetic acid. Therefore, the furfural still has a better yield when the ratio of material to liquid is 1:12. Antal s theory [9] has explained the above phenomenon. Antal considered that polysaccharide will produce large amounts of decomposition products in the solution of the lower acid concentration. It is consistent with our experimental results. Meanwhile, since the ionization rate of hydrogen ion of acetic acid is lower and the system is in the weak equilibrium condition, it will reduce the raw materials carbonization phenomenon and improve furfural yield. Therefore, the solid-liquid ratio should not exceed 1:6 when furfural hydrolyzate is sulfuric acid. Effect of reaction time on yield of furfural. As shown in Figs 3(a), an appropriate extension of the reaction time can effectively improve the yield of furfural and up to 76.68% when the reaction time is 5h. However, the yield of furfural will fall sharply after over-extended reaction time. In the Acetate Hydrolysis System (Figs 3 (b)), when achieved the furfural yield that close to the Acetate Hydrolysis System, the time should increase 20%. The higher concentration of reactants and catalysts in the Hydrolysis System cause the faster reaction rate and higher furfural yield during the initial of the reaction. Simultaneously, when the reaction time is too long, the generated aldehyde is easy to detain in the reactor and will continue

3 1384 Materials Design, Processing and Applications oxidation, polymerization under the high temperature and acidic conditions which lead to the lower furfural yield. Therefore, the reaction time should not exceed 6h either sulfuric hydrolysis or Acetic hydrolysis. Fig. 2 Effect of solid-liquid ratio on yield of furfural Fig. 3 Effect of reaction time on yield of furfural Effect of catalyst charge on yield of furfural. The conventional acid hydrolysis method of preparation furfural adds nothing which results in longer reaction time. In this paper, study on the KCL as a catalyst to the effect of the furfural synthesis. Seen Figs 4(a), it can shorten the reaction time and increase the furfural yield by adding KCL in the synthesis of furfural. The yield of the furfural will reach 76.68% when the catalyst s charge is 70% of (the raw material). During the Acetate Hydrolysis System, adding KCL also can improve the yield of furfural (see Figs 4(b)), however it s shorten time doesn t obviously after compared with sulfuric acid reaction. The mainly reason is that adding KCL as a catalyst is beneficial to the release of hydrogen ions in the reaction system, and it similar to the synergistic effect of sulfuric acid and hydrochloric can enhance the reaction rate, so the reaction time is shorten. In the Acetate Hydrolysis System, adding catalyst also change the ionization equilibrium of acetic acid which can promote the hydrolysis of acetic acid. It is similar to a strong acid- weak acid mixed system and causes the reaction time short.

4 Advanced Materials Research Vols Fig. 4 Effect of catalyst charge on yield of furfural Conclusions The optimum synthesis conditions with sulfate as hydrolytic agent: reaction temperature was 150 C,solid to liquor rate was 1:6, reaction time was 5 h and the catalyst charge was 70%.Under these conditions, the yield of furfural was over75%. The optimum synthesis conditions with acetic acid as hydrolytic agent:reaction temperature was180 C,solid to liquor rate was 1:8, reaction time was 6 h and the catalyst charge was 70%.Under these conditions, the yield of furfural was 71.21%. When the sulfate was used as hydrolytic agent, the effect of reaction Condition on furfural yield was more sensitive. The product was easy to oxidation coke and the yield was decreased. While when the acetic acid was used as hydrolytic agent, the phenomenon of oxidation coke was decreased effectively, but the reaction temperature was higher. References [1] Lichtenthaler F. W.. Carbohydr. Res.. Vol. 313 (1998), p.69 [2] Datta A, Walia S, Parmar BS.. J. Agric. Food Chem..Vol. 49 (2001), p.4726 [3] Dunning J.W., Lathrop E.C. Ind. Eng. Chem..Vol. 37 (1945), p.24 [4] A Singh, K Das, DK Sharma.JCTB. Vol. 23 (1984), p.257 [5] Y.X. Liu, H.R. Hu, B. Sun. in 3rd ICPPB, Nanjing, China(2008) [6] Y.X. Zhang, J.H. Shi, G.Q. Liu. Journal of Xinyang Nor mal University (Natural Science Edition), Vol. 15(2002), p.56 [7] Dunning J.W., E.C.Lathrop.. Ind. Eng. Chem..Vol. 37(1945), p. 24 [8] Loren C.B., Christensen L.M..Ind. Eng. Chem..Vol. 28 (1936),p.206 [9] MJ Antal, T Leesomboon, WS Mok, GN Richards. Carbohydr. Res.. Vol. 217 (1991), p.71

5 Materials Design, Processing and Applications / Study on Furfural Production from Hemicelluloses /