蔗渣预水解液酸催化制备糠醛及其萃取分离（急）

Acid-catalyzed preparation of furfural from bagasse pre-hydrolysate and its extractive separation

摘要:

以蔗渣为原料，在高温低酸浓度（H2SO4添加量占蔗渣绝干质量的0.176%）条件下预水解得到富含木糖的预水解糖液，再进一步深度酸解得到糠醛，并以混合有机溶剂实现了糠醛从水相中高效萃取分离。对蔗渣预水解条件、糠醛的有机溶剂萃取条件进行了探索，并采用FT-IR、XRD、SEM、TGA对蔗渣及预水解渣的形貌和结构进行了表征，利用紫外分光光度计对预水解过程中的木糖及深度酸解过程中的糠醛进行了定量检测。结果表明，在160 °C，液固比6：1，浓硫酸/蔗渣绝干质量为0.176%条件下，预水解液中木糖浓度最高（41.72 g/L）；该预水解液直接在170 °C条件下深度酸解90 min，溶液中糠醛浓度最高可达15.91 g/L，糠醛摩尔得率最高为59.60%。以v(1,2-二氯乙烷):v(正丁醇) = 9:1的比例混合有机溶剂对水溶液中糠醛进行萃取，萃取相体积比为v(有机相):v(水相) = 2:1，糠醛的萃取率可达93.53%。

Abstract:

: Using bagasse as raw material, the xylose-rich pre-hydrolyzed sugar solution was obtained by pre-hydrolysis under high temperature and low acid concentration (0.176% H2SO4), and then furfural was obtained by further deep acidolysis, and the separation of furfural was realized by the highly efficient extraction from the aqueous phase with a mixture of organic solvents. The pre-hydrolysis of bagasse, the deep acid hydrolysis and the organic solvent extraction of furfural were investigated; morphology and structure of bagasse and pre-hydrolysis residue were characterized by FT-IR, XRD, SEM and TGA; and quantitatively detection of the xylose in the pre-hydrolysis process and the furfural in the deep acid hydrolysis process was conducted by an UV spectrophotometer. The results showed that the highest xylose concentration (41.72 g/L) was obtained in the pre-hydrolyzed solution at 160 °C, liquid-solid ratio of 6:1, and mass percentage of concentrated sulfuric acid to bagasse (oven dry) as 0.176%. The pre-hydrolyzed solution was directly deep acidified at 170 °C for 90 min, the concentration of furfural in the solution could reach up to 15.91 g/L, with the highest molar yield of furfural as 59.60%. Extraction of furfural from aqueous solution was carried out by mixing organic solvents in the ratio of v(1,2-dichloroethane):v(n-butanol) = 9:1, and the extraction rate of furfural was up to 93.53% when the volume ratio of the extracting phase was v(organic phase):v(aqueous phase) = 2:1.