6,504 research outputs found

    Cellulose acetate prepared with energy plant of miscanthus and screening catalysts

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    随着化石资源日益匮乏,利用生物质来代替化石资源受到全世界关注。本研究以能源植物芒草为原料,利用NaOH/H2O2水溶液体系进行预处理,制备出较高纯度纤维素。芒草纤维素经活化、酯化反应后制备出高取代度的芒草醋酸纤维素,并筛选出氯化铁为催化剂制备醋酸纤维素,同时对制得样品进行表征。 (1)以NaOH/H2O2水溶液体系对芒草生物质预处理,制得芒草纤维素。以芒草纤维素组分含量、固相得率和组分脱除率为指标对预处理温度、时间和次数进行了优化,得到的芒草纤维素的最佳制备条件:预处理温度70℃,预处理时间3h,预处理次数3次,制得芒草纤维素的纤维素、半纤维素和木质素含量分别为75.3%、17.3%、5.1...With the shortage of fossil resources, using biomass as a substitute for fossil resources became a hotspot of study. A procedure for synthesizing cellulose acetate with high degree of substitution from miscanthus biomass was developed and we also choose ferric chloride as a new catalyst to prepare cellulose acetate. The miscanthus biomass, miscanthus cellulose and cellulose acetate were characteri...学位:工学硕士院系专业:能源学院_能源化工学号:3242013115229

    Controllable Synthesis of Cellulose Esters by Homogeneous Transesterification and Its Application

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    随着石油、煤炭等不可再生资源的日益枯竭,为了满足社会经济可持续发展的需要,以纤维素生物质为原料制备高附加值化工品及燃料的研究逐渐成为人们研究的热点。本文以多种来源的纤维素为原料,以N,N-二甲基乙酰胺/氯化锂(DMAc/LiCl)为溶剂体系,建立一种温和快速均相酯交换可控制备纤维素酯的方法,改进了纤维素在DMAc/LiCl体系中的溶解过程,优化了酯交换反应制备工艺,分析了纤维素酯类产物特征,探索了一种SEC测定纤维素分子量的方法,为纤维素酯的后续研究及应用提供理论基础和依据。 研究微晶纤维素在DMAc/LiCl体系中的溶解特性,分析了溶剂交换条件及氯化锂含量等对纤维素溶解过程的影响。通过研究...Driven by the growing fear of the depletion of oil, coal and other non-renewable resources, and the global need to focus on renewable and earth-abundant resources, high value-added cellulose-based functional materials and polymers are now spotlighted once again and widespread concerned. A series of studies were carried out in this dissertation on the mild and rapid methods of cellulose esters prep...学位:工学博士院系专业:能源学院_能源化工学号:3242013015402

    Strategies of Prior-Fractionation for the Graded Utilization of Lignocellulose

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    木质生物质是地球上最丰富的一类生物质资源,主要由碳水化合物高分子(纤维素、半纤维素)和芳族聚合物(木质素)组成。木质纤维组分的清洁高效分离,是实; 现多元化、高值化生物精炼的重要基础。本文首先讨论了基于分级利用的组分分离技术与基于制备纤维素乙醇的预处理技术的不同之处;其次,梳理归纳了五种木质; 纤维组分优先分级分离策略:纤维素优先分离,木质素优先分离,半纤维素优先分离,木质素和半纤维素优先分离以及纤维素和半纤维素优先分离;再次,基于半纤; 维素优先分离策略,对国内相关的产业化应用进行了评述;最后,对木质生物质组分分离技术的当下定位和发展前景进行了总结与展望,以期对木质生物质的三大组; 分有较全面的价值观念和利用思路,并对木质生物质精炼技术的发展提供借鉴与参考。Lignocellulosic materials contributing the large proportion to the biomass resource are mainly composed of carbohydrate polymers (cellulose, hemicellulose), and aromatic macromolecules (lignin). Pre-fractionating lignocellulose is considered as the foundational step to establish an economical and sustainable lignocellulosic biorefinery. Firstly, the distinction between lignocellulose fractionation technologies and pretreatment methods for cellulosic ethanol production is discussed. Afterwards, five prior-fractionating strategies of lignocellulose for the biorefinery process are elaborated, including cellulose-first processing, lignin-first processing, hemicellulose-first processing, lignin & hemicellulose-first processing, and cellulose & hemicellulose-first processing. And then industrial applications of hemicellulose-first processing in our country are reviewed. Ultimately, the future perspective on lignocellulose fractionation technologies are given. The aim of this review is to provide new insights into the lignocellulosic biorefinery based on the fractionating of lignocellulose.National Natural Science Foundation of China [21676223, 21506177];; Fujian Provincial Development and Reform Commission, China [2015489];; Fundamental Research Funds for the Central Universities [20720160087,; 20720160077, 20720170062]; Natural Science Foundation of Fujian Province; of China [2016J01077, 2015J05034]; Education Department of Fujian; Province [JZ160398

    天然高分子甲壳素类纤维的研究进展

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    :综述了甲壳素及其衍生物纤维的制备和性能 .介绍了制备甲壳素纤维的黄化法、含卤溶剂法和酰胺 氯化锂法 .总结了壳聚糖纤维制备的一般方法和性能 .简要介绍了甲壳素 /壳聚糖酯类和醚类衍生物的纤维 .讨论了甲壳素类纤维的应

    DETERMINATION OF SPARTINA ANGLICA STOCK COMPONENTS BY NREL METHOD

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    采用美国国家可再生能源实验室(NREL)方法定量大米草原料中纤维素、半纤维素及木质素。72%浓硫酸水解1 h、4%稀硫酸水解1 h可将大米草的纤维素、半纤维素降解为可用HPLC定量的单糖,适宜的样品添加量为0.3 g。同时,NREL法测定大米草纤维素、半纤维素及木质素的含量分别为32.92%、27.65%和24.2%。这三个组分的含量是评价大米草预处理、酶解及发酵工艺条件的重要依据。Cellulose, hemicellulose and lignin of Spartina anglica were quantified by National Renewable Energy Lab(NREL) method. It was showed that the cellulose and semicellulose of S. anglica could be degraded to mono-sugars which could be quantified by HPLC after it was hydrolyzed with 72% concentrated sulphuric acid for 1 h and 4% dilute sulphuric acid for 1h with the appropriate additive amount of 0.3 g sample. Meanwhile, the contents of cellulose, hemicellulose and lignin of S. anglica determined by NREL method were 32.92%, 27.65%and 24.2% respectively. The contents of these three fractions are important basis for the evaluation of the pre-processing, enzymatic hydrolysis and fermentation conditions of S. anglica.闽海高新[2014]25号“滩涂大米草高值化综合利用关键技术与示范”项目;; 福建省生物医药产业中试与检测技术公共服务平台;; 海洋生物制品福建省高校应用技术工程中

    Chemical Synthesis of Lactic Acid from Lignocellulosic Compouds Catalysed by Pb(II) or Al(III)-Sn(II)

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    催化转化自然界中含量丰富且可再生的纤维素类生物质资源制备平台化学品有非常重要的意义。尤其是,在非氢条件下将纤维素转化为与其化学组成类似的乳酸,是纤维素转化中最具原子经济效益的路径之一,然而相关的研究尚十分有限。本篇论文研究了氮气氛下,简单金属离子Pb(II)和离子组合Al(III)-Sn(II)催化纤维素及其单体葡萄糖转化为乳酸反应,主要取得以下结果: 研究发现,简单金属离子Pb(II)可有效地催化纤维素及葡萄糖转化制乳酸。氮气氛下,在463K反应6h后,Pb(II)催化球磨纤维素制乳酸的收率高达70.2%。此外,该体系还可转化未经纯化的真实生物质,如茅草、甘蔗渣和麸皮等,乳酸收率达60%以...The transformation of abundant and renewable cellulose or cellulose-derived carbohydrates into platform chemicals is the key to establishing biomass-based chemical processes. The system that is capable of catalyzing the conversion of cellulose into lactic acid in water without consuming hydrogen is one of the most atom-economic pathways for converting cellulose. At present, research on this field ...学位:理学博士院系专业:化学化工学院_物理化学学号:2052010015367

    Synthesis and characterization of cellulose acetate with high degree of substitution from miscanthus

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    以芒草为原料,用Na OH/H_2O_2溶液体系预处理制备芒草纤维,在冰醋酸环境下,以浓硫酸为催化剂与醋酸酐酯化制备芒草醋酸纤维素。优化了预处理条件:温度、时间、次数和酯化条件:催化剂量、温度、时间、醋酸酐量,最佳条件下制备出的芒草纤维的纤维素、半纤维素和木质素的质量分数分别为75.3%、17.3%、5.1%,制备出芒草醋酸纤维素的取代度DS=2.8,特性黏度[η]=1.24 d L/g,达到美国联邦贸易委员会指南认定的三醋酸纤维素标准。利用扫描电镜(SEM)和热分析(TG、DSC)对制得样品进行表征。结果表明,可以利用Na OH/H_2O_2水溶液体系预处理芒草原料制备芒草纤维,并进一步酯化制备出高取代度的醋酸纤维素。A procedure for synthesizing cellulose acetate with high degree of substitution from miscanthus biomass is developed. The miscanthus fiber is prepared by pretreatment of miscanthus biomass with Na OH / H_2O_2,which is then reacted with acetic anhydride in an acetic acid solvent to synthesize cellulose acetate by using concentrated sulfuric acid as catalyst. The effects of the pretreatment factors( such as pretreatment temperature,time and number of times) and the esterification factors( such as catalyst volume,reaction temperature,reaction time and acetic anhydride volume) are studied. Under the optimal conditions,the contents of cellulose,hemicellulose and lignin for prepared miscanthus fiber are75. 3%,17. 3% and 5. 1%,respectively. The degree of substitution( DS) and the intrinsic viscosity( [η ]) of the obtained miscanthus cellulose acetate are 2. 8 and 1. 24 d L / g,respectively. The miscanthus biomass,fiber and cellulose acetate are characterized by SEM,TG and DSC. This study shows that cellulose acetate with high degree of substitution can be prepared from miscanthus biomass pretreated with Na OH / H_2O_2.国家自然科学基金(21303142;31170067);; 福建省中青年教师教育科研项目(JA14010);; 厦门市海洋经济发展专项资金项目(14GZP59HJ29);; 福建省海洋高新产业发展专项项目(闽海洋高新[2014]25号);; 厦门大学校长基金(20720150090

    The Role and Mechaninsm study of IL-20-related Cytokines contribute to Autoimmune Myocarditis in Mice

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    目的:免疫相关因素与心肌炎引起的心肌纤维化密切相关。前期研究表明,IL-10家族成员在心肌炎慢性期心肌纤维化的形成过程中发挥重要作用。IL-20是最新发现的IL-10家族成员之一,具有调节细胞增殖和分化的作用。但IL-20是否参与心肌炎心肌纤维化过程尚不清楚。本课题通过实验探讨IL-20及其相关因子对小鼠自身免疫性心肌炎(EAM)心肌纤维化的影响及可能的分子调节机制。 方法:利用小鼠心肌肌球蛋白多肽MyHC6l4-629和完全弗氏佐剂充分混合后,于第0天和第7天皮下注射建立小鼠EAM模型;组织切片H&E染色及Masson染色评估心肌组织炎症及纤维化程度;RealtimePCR及Western...Aims: Immune-related cytokines are closely associated with myocardial fibrosis induced by myocarditis. Previous studies had shown IL-10 family members play an important role in the formation of myocardial fibrosis in chronic myocarditis. IL-20 is one of the latest findings of the IL-10 family members which play a role in regulating the proliferation and differentiation of cells. However, it is unc...学位:医学硕士院系专业:医学院_内科学学号:2452012115314

    Material and Energy Conversion of Integrated 100,t/a-Scale Bio-Jet Fuel-Range Hydrocarbon Production System via Aqueous Conversion of Biomass

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    以农业废弃物生物质为原料,利用水相转化技术,进行了百吨/年规模生物航油类烃(C8~C15)合成试运行.过程中采用两步酸解法分别将玉米秸秆中半纤维素和纤维素转化为糠醛和乙酰丙酸,作为生物质基平台化合物.在碱性条件下糠醛与乙酰丙酸经Aldol缩合反应实现碳链增长,生成的长链含氧中间体经过低温预加氢、高温加氢脱氧及精制,生成C8~C15范围内液态烃,可作为生物航油组分.以试运行实验结果为基础,进行了过程的物质与能量转化分析.结果表明,该路线获得液态烃类的基本性质满足合成航油ASTM-7566标准要求,并充分利用了原料中纤维素和半纤维素组分,是一条基于生物质的长链液态烃合成路线,1t航油约需10~12t干基玉米秸秆

    Preparation and Characterization of Natural Polymer Cellulose or Sodium Alginate Based Composite Gels

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    水凝胶,是一类具有三维交联网络结构的聚合物材料,其特征是能够吸收大量的水而不溶解,并能保持一定的形状和具有一定的强度,这一特点使水凝胶成为一类重要的功能高分子材料,在医疗、化工、农业等方面具有广阔的应用。天然高分子是一类可持续发展的资源,具有良好的生物相容性、生物可降解性、资源丰富等优点,成为制备新型凝胶的首选原料。另外,面对目前地球上的化石资源日益减少的严峻形势,利用和开发高值化天然高分子材料有助于应对逐渐呈现的石油危机、能源危机。本论文采用纤维素或海藻酸钠天然高分子为原料,制备了多种新型复合水凝胶材料。采取多种手段和先进方法详细表征了所得复合水凝胶,并研究其性能。结果表明,这些水凝胶材料除...Hydrogel is three-dimensional network consisting of polymer, which can absorb large amounts of water without dissolving and maintain a certain shape and strength. Due to these unique properties, hydrogels have wide applications in the fields of medical treatment, chemical industry, agriculture and so on. Natural polymers, the most abundant renewable resource on earth with biocompatibility and biod...学位:理学硕士院系专业:材料学院_高分子化学与物理学号:2072014115006
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