Studies On Preparation Of Furfural And Comprehensive Utilization Of Furfural Residue

In today’s society, the entire world economy is built on the basis of fossilresources such as oil and coal. The great development and utilization of fossil fuelresources has accelerated the consumption of fossil resources. Because coal and oilare non-renewable resources，renewable resources come into the people’s vision.Biomass is currently considered the most likely materials to replace oil and otherfossil fuels to produce chemical products. The development and utilization of biomassresources, more and more attention has been paid.Biomass is mainly composed of hemicellulose, lignin and cellulose.Hemicellulose is hydrolyzed to produce xylose, and xylose in further dehydration canbe prepared furfural. Furfural molecular structure, which has unsaturated double bond,oxygen ether bond, diene functional group, is rather special. Therefore, the Furfuralnature is much lively which can perform hydrogenation, oxidation, chlorination,nitration, and condensation and other reactions. Furfural can produce a large numberof derivatives and it has been widely applied in the field of medicine, food, syntheticresin, petroleum refining, pesticides and synthetic fibers. After a series ofhydrogenation and reduction reactions, furfural can also be prepared hydrocarbons,which has a potential value in the fuel sector. The furfural industrial production is theraw material resources to take advantage of a very successful example. As early as the1920s, the production of furfural has been achieved industrialization. China is thelargest country in the world on the furfural production and exports, and there arehundreds of large and small furfural plants in China. In furfural industry there aremany problems, such as low utilization of raw material, the low yield of furfural, energy consumption and serious environmental pollution, needed to be resolved. Thedevelopment of enterprises of furfural is so greatly restricted, and furfural industry inChina has been even in a semi-paralyzed.In this paper, xylose was used as the raw material to study the second step of thetwo-step method for the production of furfural. Xylose was dehydrated to producefurfural in the atmospheric conditions. The optimal reaction conditions: concentrationof sulfuric acid10%,10%of the xylose concentration, toluene amount of150mL,water10mLl, the amount of sodium chloride2.4g. The best yield of furfural was82%.DMSO （dimethyl sulfoxide）, NaCl, and FeCl₃increased the yield of furfural. SingleFeCl₃without acid had poor advancement in xylose dehydration to furfural. We alsostudied the production of furfural using a commercially available solid acid catalyst.The best conditions of the experiment is the catalyst2.5g, the xylose2g, DMSO30mL,reaction temperature160℃.This method has the advantage of solid acid recycle, easyseparation, and a small pollution on the environment.Then the corn cob was used as the raw material. In the amount of water rarely,the organic solvent toluene was used as the extractant.Furfural was prepared underlow pressure conditions （reactor）, and this method of water consumption is minimal.The optimal reaction conditions: the reaction temperature of140℃, toluene25ml,corncob1g,6%of the sulfuric acid concentration, reaction time of3.5h. Underoptimal conditions furfural yield was44%. The reaction temperature and acidconcentration is the main influencing factors of the reaction. The near anhydrousmethod was performed for production of furfural at atmospheric pressure usingcorncob as raw material. The optimal experimental conditions: corncob2g, DMSO5ml,15%sulfuric acid5mL, reaction time5h, extracted with toluene dosage of50mL, best furfural yield was45%. The introduction of DMSO as solvent atatmospheric pressure, improved the yield of furfural close to yield of low pressure.The amount of DMSO should not be too large, because extraction of organic solventswould result in the loss.The furfural residue was corncob residue after extraction of furfural. Furfuralresidue, which contains large amounts of lignin and cellulose, is an excellent carbon source. More production of furfural residue was burned to provide heat for thereaction, resulting in a tremendous waste of resources and environmental pollution. Inthis thesis, furfural residue was activated by phosphoric acid for preparation ofactivated carbon. Optimal preparation conditions: furfural residue2g, phosphoric acid（85%）6ml, carbonized at200℃for60min or300℃for30min, and activated at500℃for105min。 Pore volume and surface area of activated carbon weredetermined. Furfural residue contains cellulose, so furfural residue was used as rawmaterial to produce hydrothermal carbon.Furfural wastewater contains large amounts of organic, so it can not be directlydischarged.We take a variety of biomass materials as an adsorbent for furfuralwastewater preliminary treatment. The effects of the content of acetic acid andfurfural in wastewater were investigated.In summary, furfural was prepared from xylose. The yield of furfural reached83%. Corncob as raw material reduced the amount of water to avoid wastewaterdischarges to the environment. Preparation of activated carbon and hydrothermalcarbon from furfural residue was investigated. Furfural production and waste watertreatment to provide valuable suggestions for the development of furfural industry.