【摘要】：本課題研究了白腐真菌預(yù)處理的稻稈和麥稈在甲醇介質(zhì)中的超臨界醇解過程,并通過考察白腐真菌預(yù)處理的微晶纖維素、木聚糖和堿性木質(zhì)素在甲醇中的超臨界醇解給出了白腐真菌預(yù)處理可能影響秸稈醇解的機(jī)理。本研究探討了白腐真菌的不同預(yù)處理時(shí)間對(duì)稻稈和麥稈的超臨界醇解所得可溶物收率的影響,確定白腐真菌預(yù)處理的優(yōu)化條件;通過傅立葉紅外光譜儀(FTIR)、氣相色譜/質(zhì)譜聯(lián)用儀(GC/MS)和傅里葉變換離子回旋共振質(zhì)譜儀(ESI FTICRMS)等分析了醇解可溶物的化學(xué)組成,采用FTIR、掃描電子顯微鏡(SEM)、X射線光電子能譜儀(XPS)、X射線粉末衍射儀(XRD)和熱重分析了白腐真菌預(yù)處理的秸稈的化學(xué)組成等性質(zhì)。結(jié)果表明,白腐真菌預(yù)處理的秸稈的超臨界醇解優(yōu)化條件為:稻稈經(jīng)過白腐真菌預(yù)處理10天后,在260oC下反應(yīng)30分鐘,醇解所得可溶物的收率最高;麥稈經(jīng)過白腐真菌預(yù)處理5天后醇解所得可溶物的收率最高,在同樣反應(yīng)條件下,醇解所得可溶物的收率最高。白腐真菌預(yù)處理秸稈醇解所得可溶物組分的FTIR和GC/MS分析表明:兩種秸稈超臨界醇解所得可溶物的化學(xué)組分都較為復(fù)雜,主要包括酯、酮、酚、和醚類等化合物;不同預(yù)處理時(shí)間對(duì)醇解所得產(chǎn)物的組分分布有一定的影響,預(yù)處理時(shí)間的延長,可提高酯類化合物的產(chǎn)率并選擇性地生成長鏈烷酸酯,尤其是棕櫚酸甲酯,(9Z,12Z)-十八碳-9,12-二烯酸甲酯和(E)-十八碳-11-烯酸甲酯等三種長鏈烷酸酯;白腐真菌預(yù)處理秸稈醇解所得可溶物組分的ESI FTICRMS分析表明:預(yù)處理秸稈醇解所得產(chǎn)物中的含氧化合物和含氮化合物較未處理秸稈醇解所得產(chǎn)物差異顯著,化合物種類有一定減少,同時(shí)含氧化合物和含氮化合物分別呈現(xiàn)向O4類化合物和N2O4類化合物的定向轉(zhuǎn)化。秸稈的FTIR、SEM、XPS、XRD和熱重分析表明:白腐真菌預(yù)處理可以有效地破壞秸稈的晶型結(jié)構(gòu),促進(jìn)秸稈醇解。分別以微晶纖維素、木聚糖和堿性木質(zhì)素為原料,進(jìn)行不同預(yù)處理時(shí)間生物質(zhì)組分的超臨界醇解研究,考察了其可溶物組分的收率,結(jié)果表明:纖維素和木聚糖可以獲得較優(yōu)的醇解產(chǎn)物收率,木質(zhì)素的醇解產(chǎn)物收率變化不明顯。通過GC/MS分析生物質(zhì)組分醇解可溶組分的化學(xué)組成,結(jié)果表明:預(yù)處理后的纖維素和木聚糖的醇解產(chǎn)物組成較未處理的纖維素和木聚糖的醇解產(chǎn)物出現(xiàn)顯著差異,酯類化合物的含量顯著增加,而木質(zhì)素的醇解產(chǎn)物未出現(xiàn)明顯差異。結(jié)合其本身結(jié)構(gòu)和相關(guān)文獻(xiàn)提出了白腐真菌預(yù)處理可能影響秸稈超臨界醇解的機(jī)理。
[Abstract]:The supercritical alcoholysis of rice stalk and wheat stalk pretreated by white rot fungi in methanol medium was studied in this paper, and the microcrystalline cellulose pretreated by white rot fungus was investigated. The supercritical alcoholysis of xylan and basic lignin in methanol gave the mechanism that the pretreatment of white rot fungi might affect the alcoholysis of straw. In this study, the effects of different pretreatment time of white rot fungi on the yield of soluble matter obtained by supercritical alcoholysis of rice stalk and wheat stalk were studied, and the optimum conditions of pretreatment of white rot fungus were determined. The chemical composition of alcoholysis was analyzed by Fourier transform infrared spectrometer (FTIR), gas chromatography / mass spectrometry (GC/MS) and Fourier transform ion cyclotron resonance mass spectrometer (ESI FTICRMS). Scanning electron microscope (SEM) (SEM), X ray photoelectron spectroscopy (SEM), X) (XPS), X ray powder diffractometer (XRD) and thermogravimetric analysis (TGA) were used to analyze the chemical composition of straw pretreated by white rot fungi. The results showed that the optimum conditions of supercritical alcoholysis of straw pretreated by white rot fungi were as follows: after pretreatment with white rot fungi for 10 days, the yield of soluble matter was the highest when rice stalk was treated with white rot fungus for 30 minutes under 260oC. The yield of soluble matter of wheat stalk was the highest after pretreatment with white rot fungi for 5 days, and the yield of soluble substance was the highest under the same reaction conditions. The FTIR and GC/MS analysis of soluble components obtained from the alcoholysis of straw by white rot fungi showed that the chemical components of the soluble compounds obtained from the alcoholysis of the two kinds of straw were complex, including esters, ketones, phenols and ethers. Different pretreatment time has a certain effect on the distribution of components of alcoholysis products. The increase of pretreatment time can increase the yield of ester compounds and selectively grow chain alkanoate, especially methyl palmitate, (9Z, 9Z). 12Z) -octadecyl -9-dienoic acid methyl ester and (E) octadecyl-11-enoic acid methyl ester; The ESI FTICRMS analysis of soluble components obtained from the alcoholysis of straw by white rot fungi showed that the oxygen compounds and nitrogen compounds in the alcoholysis products were significantly different from those obtained from untreated straw alcoholysis. At the same time, the oxygen and nitrogen compounds showed the directional transformation to O _ 4 and N2O4 respectively. FTIR,SEM,XPS,XRD and thermogravimetric analysis showed that the pretreatment of white rot fungi could effectively destroy the crystal structure of straw and promote the alcoholysis of straw. Using microcrystalline cellulose, xylan and alkaline lignin as raw materials, the supercritical alcoholysis of biomass components at different pretreatment time was carried out, and the yield of soluble components was investigated. The results showed that the yield of alcoholysis products could be obtained by cellulose and xylan, but the yield of lignin alcoholysis products did not change obviously. The chemical composition of alcoholysis soluble components of biomass components was analyzed by GC/MS. The results showed that the composition of alcoholysis products of cellulose and xylan after pretreatment was significantly different from that of cellulose and xylan after pretreatment. The contents of ester compounds increased significantly, but the alcoholysis products of lignin showed no significant difference. Combined with its own structure and related literature, the mechanism that pretreatment of white rot fungi may affect supercritical alcoholysis of straw was put forward.
【學(xué)位授予單位】：中國礦業(yè)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2017
【分類號(hào)】：TK6
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本文編號(hào)：2392721