本文關(guān)鍵詞： 水稻秸稈 半纖維素 樹脂 色譜法 硼氫化鈉 木糖 木糖醇　出處：《西南交通大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：半纖維素在農(nóng)林生物質(zhì)三大組分中是目前利用最少的部分。半纖維素中存在著豐富的木聚糖結(jié)構(gòu),木聚糖可水解成木糖,木糖在一定的條件下可以轉(zhuǎn)化為木糖醇。木糖和木糖醇因其獨特的理化性能,在食品和醫(yī)藥等領(lǐng)域有著廣泛的應(yīng)用。通過合適的方法將半纖維素轉(zhuǎn)化為木糖或木糖醇,是半纖維素有效利用的重要途徑。本論文研究了利用水稻秸稈半纖維素轉(zhuǎn)化并分離木糖以及將木糖轉(zhuǎn)化為木糖醇,主要開展的工作如下:首先,基于課題組前期在農(nóng)作物秸稈組分環(huán)�；蛛x研究的基礎(chǔ)上,以蒸爆水稻秸稈為原料,分別采用微波輔助酸水解法和水煮法進行秸稈半纖維素的分離。微波輔助酸水解法水解半纖維素時,當(dāng)微波功率700W,硫酸0.6mol/L,溫度100℃,反應(yīng)20 h后,剩余固體中半纖維素的殘留量僅0.59%;用水煮法來處理蒸爆水稻秸稈,在沸水浴中水煮兩次,每次水煮1h,測得剩余固體中半纖維素的殘留量為2.99%。其次,以蒸爆水稻秸稈水煮液為原料,采用微波輔助酸水解法進行水解,在硫酸濃度0.3mol/L,溫度90℃,微波功率700W,反應(yīng)10h的條件下,蒸爆水稻秸稈水煮液中的半纖維素轉(zhuǎn)化為木糖的百分率達到90.83%。對蒸爆水稻秸稈水解液進行中和,得到中和液,用D301和732樹脂對中和液進行凈化,當(dāng)中和液與樹脂的體積比為1:1時,凈化液已具有透明性,如果只用D301陰離子樹脂凈化中和液,木糖的損失為10.73%,緊接著再用732陽離子樹脂凈化,732陽離子樹脂凈化所造成的木糖的損失為16.62%。D301樹脂凈化中和液,隨著中和液與樹脂的體積比從1:2至1:4變化時,凈化液越來越澄清透明,木糖的損失從21.68%增加到24.82%,并且淋洗樹脂所需的蒸餾水的量從3倍中和液體積增加至4倍中和液體積。再次,用色譜法分離木糖,找到的最好的淋洗液為甲醇:乙酸乙酯=1:120(v/v)和甲醇:乙酸乙酯=1:15(v/v),分離產(chǎn)物固液分離,得到固體部分木糖純度為79.48%和液體部分木糖純度為53.42%的產(chǎn)物,以絕干蒸爆水稻秸稈為基準(zhǔn)所得的木糖水解產(chǎn)率為9.49%,木糖分離產(chǎn)率(固體部分)為4.61%,木糖分離產(chǎn)率(液體部分)為1.45%。最后,用硼氫化鈉(NaBH_4)堿性溶液來轉(zhuǎn)化木糖為木糖醇,當(dāng)以商品木糖為原料,NaBH_4與木糖的摩爾比為0.5:1時,轉(zhuǎn)化率為94.23%,產(chǎn)物中木糖醇的質(zhì)量分?jǐn)?shù)為78.87%。繼續(xù)增大NaBH_4的量,NaBH_4與木糖的摩爾比從0.5:1到0.8:1變化時,轉(zhuǎn)化率略有增加,最高為95.89%,但產(chǎn)物中木糖醇的質(zhì)量分?jǐn)?shù)在逐漸下降,從78.87%下降為68.79%。蒸爆水稻秸稈水煮液經(jīng)不同處理后與NaBH_4堿性溶液反應(yīng)轉(zhuǎn)化其中的木糖為木糖醇,當(dāng)蒸爆水稻秸稈中和液與D301樹脂的體積比為1:4時,得到的凈化液與NaBH_4堿性溶液反應(yīng),其中的木糖轉(zhuǎn)化為木糖醇的轉(zhuǎn)化率為94.73%,基本上已經(jīng)達到原料為商品木糖時的轉(zhuǎn)化率。
[Abstract]:Hemicellulose is the least utilized part of the three major components of biomass in agriculture and forestry. There are abundant xylan structures in hemicellulose and xylan can be hydrolyzed into xylose. Xylose can be converted to xylitol under certain conditions. Xylose and xylitol have unique physical and chemical properties. Hemicellulose is widely used in food and medicine. Hemicellulose is converted to xylose or xylitol by appropriate methods. This paper studies the conversion and separation of xylose and the conversion of xylose to xylitol using rice straw hemicellulose. The main work is as follows: first. Based on the research on the environmental protection separation of crop straw components in the earlier period of the research group, rice straw was used as raw material. The hemicellulose was separated by microwave-assisted acid hydrolysis method and water-boiling method respectively. When the microwave power was 700W and the sulfuric acid 0.6 mol / L was used, the hemicellulose was hydrolyzed by microwave-assisted acid hydrolysis. After reaction at 100 鈩，

本文編號：1450354