氧化氨解木质素化学结构特性的研究

对麦草和木材碱木质素氧化氨解反应产物的化学结构进行研究。结果表明 ,反应产物中有羧基产生 ;芳环的破坏主要发生在升温阶段。在木质素的部分芳环被氧化断裂的同时还发生了脱甲氧基反应。硝基苯氧化降解的结果表明 ,木材和麦草碱木质素分别有近 1 /2和 2 /3的未缩合单元被破坏。     

麦草碱木质素的过氧化氢氧化氨解Ⅰ.影响过氧化氢氧化氨解反应的主要因素

用过氧化氢和氨水对麦草碱木质素进行氧化氨解 ,分析了氨水用量、过氧化氢用量、反应温度、时间和木质素浓度对产物总氮及有效氮含量的影响。结果表明 ,过氧化氢用量对工业木质素的氧化氨解反应的影响最大 ,而木质素浓度对产物含氮量的影响最小     

工业木质素氧化氨解反应研究

对麦草碱木质素和木材硫酸盐木质素的氧化氨解反应进行研究。对反应产物pH值的变化及氮化物的组成分析结果表明 ,改性木质素的总氮含量分别可达 1 0 .7%和 1 3.43% ,总氮中有近一半是无机氮。在 1MPa氧压和 1 40℃条件下麦草和木材碱木质素的最佳反应时间分别为 30min和 45min。     

木质素的电氧化研究及应用

综述了木质素的电氧化机理研究及其应用。木质素的电氧化有两种机理 ,一种是失去两个电子产生苯氧正离子 ,然后苯氧正离子与水或甲醇反应 ;而在碱性介质中 ,倾向于发生单电子转移 ,产生苯酚自由基 ,然后形成碳碳双键。在一定条件下 ,电氧化会导致苯环的减少和羧基的增加 ,具有脱甲氧基的作用。木质素的电氧化可应用于木质素功能化、木质素降解、纸浆的漂白和废水漂白。     

木质素氧化降解制备酚类化合物研究进展（英文）

木质素作为可再生资源被认为是最具有潜力的苯酚替代物用于制备酚醛树脂,作为制浆造纸工业副产品,木质素来源丰富且低毒,但是木质素具有三维空间网状结构,分子量大,反应活性低。到目前为止,很多方法（如热化学转化、热裂解、液化、超临界水处理、氧化、还原和水解等）用于将大分子木质素降解为小分子物质,得到的小分子物质中含有重要的化工中间体可以用来制备多种产品。本论文综述了木质素氧化降解得到酚类物质的研究现状,并展望了木质素工业化的应用前景。     

木质素氧化降解制备酚类化合物研究进展

木质素作为可再生资源被认为是最具有潜力的苯酚替代物用于制备酚醛树脂,作为制浆造纸工业副产品,木质素来源丰富且低毒,但是木质素具有三维空间网状结构,分子量大,反应活性低。到目前为止,很多方法(如热化学转化、热裂解、液化、超临界水处理、氧化、还原和水解等)用于将大分子木质素降解为小分子物质,得到的小分子物质中含有重要的化工中间体可以用来制备多种产品。本论文综述了木质素氧化降解得到酚类物质的研究现状,并展望了木质素工业化的应用前景。     

麦草碱木质素的过氧化氢氧化氨解 Ⅱ.氧化氨解对木质素主要官能团的影响

研究了麦草碱木质素的过氧化氢氧化氨解对主要官能团的影响。结果表明过氧化氢用量、反应温度和时间对氧化氨解木质素的甲氧基、酚羟基和羧基含量均有明显的影响 ,在反应中甲氧基和酚羟基含量下降 ,而羧基含量呈上升趋势。木质素的甲氧基、羧基含量与总氮、有效氮含量均呈较好的线性关系。     

木质素的结构及其化学改性进展

系统地从元素组成、结构主体以及主体的联结方式等方面介绍了木质素的结构;并综述了木质素在磺化反应、氧化反应、接枝共聚反应、缩合反应、曼尼希反应、烷基化反应、羟烷基化反应等化学改性反应中的研究进展。通过改变木质素的结构,可以改善木质素的性质,扩大木质素的应用范围,对于天然资源的利用、环境的保护均具有重大意义。引用文献 38篇。     

电极材料对木质素磺酸盐电氧化效果影响的研究

用C、Ti合金和PbO2电极对木质素磺酸盐进行电氧化．结果表明，C和Ti合金作为阳极，氧化能力弱，氧化效果不显著；PbO2电极氧化木质素磺酸钠，效果明显，氧化前后，其IR，UV和1H－NMR谱图发生显著变化，－COOH含量升高，苯环结构被破坏。其数均分子量随氧化电量的增加而有一个上升到降低的过程，说明电氧化过程中聚合与降解反应共存。电氧化能改善木质素横酸盐作为水泥添加剂的分散性能。     

二氧化铅膜电极用于木质素磺酸盐电氧化反应的研究：Ⅱ.电解条件？…

用一种新型电极－ＰｂＯ２膜电极对木质素磺酸盐溶液进行电氧化反应，研究了溶液ｐＨ值，电解电压和电量对电氧化过程中木质素磺酸盐脱色反应的影响。结果表明，当电解电解维持在２．５Ｖ左右时能有效地使木质素磺酸盐发生脱色反应，ｐＨ值条件有利于脱色反应的进行，电解电量的增加可提高脱色程度。     

Fe-based catalysts for oxygen reduction in proton exchange membrane fuel cells with cyanamide as nitrogen precursor and/or pore-filler

Fe/N/C catalysts for oxygen reduction reaction were synthesized via impregnation or ballmilling. The role of cyanamide (CM) as nitrogen precursor and/or pore-filler for a highly microporous carbon (Black Pearls 2000) was investigated. The use of CM in this work resulted in two main differences compared with phenanthroline from our previous work; (i) ballmilling the precursors did not result in improved activity of the resulting catalysts, and (ii) the activity after the first pyrolysis in argon was relatively high, but did not increase after a second pyrolysis in NH₃. These differences may be explained by TGA measurements of both pore-fillers, where complete gasification of CM is observed at temperatures above 750 °C in Ar, while pyrolysis of phenanthroline in Ar results in 20 wt% residual carbon-based material. Consequently, when using CM as pore-filler with a highly microporous carbon support, the maximum microporous surface area and nitrogen content is reached after only a single pyrolysis in Ar. The most active catalyst prepared with CM was obtained by pyrolysing in Ar at 950 °C a catalyst precursor containing 1 wt% Fe, 80 wt% CM and Black Pearls 2000. This catalyst possessed about 1/6th the catalytic activity of best reported using phenanthroline as a pore-filler. Changing the carbon support had effects on the activity and stability of the catalysts. The catalysts made with a non-porous furnace black (N330) or carbon nanotubes as a carbon support were more stable but less performing than those using carbon supports having high microporous surface area like Black Pearls 2000 or Ketjenblack. The desirable properties for a pore-filler molecule used in the synthesis of Fe/N/C-catalysts by the pore-filling method are discussed.     

氯化聚乙烯橡胶自由发泡性能的研究

试验研究氢氧化铝、滑石粉和三氧化二锑的用量对氯化聚乙烯橡胶(CM)自由发泡材料的泡孔结构、密度和阻燃性能的影响。结果表明:随着氢氧化铝或滑石粉填料用量的增大,发泡CM的密度增大,泡孔尺寸变小,均匀性变差,发泡体的氧指数随填料用量增大而不断增大,阻燃性能得到提高。三氧化二锑对CM发泡材料泡孔结构及密度影响不大,但在氢氧化铝用量为20份时,少量三氧化二锑能显著提高材料的氧指数。     

Mg、Ce修饰纳米Al_2O_3负载Ni催化剂对CH_4、CO_2重整反应制合成气的影响

考察了助剂Mg、Ce修饰的纳米A l2O3负载N i催化剂对CH4、CO2重整反应制合成气的反应性能影响,采用正交实验筛选催化剂。结果表明,N i含量在9%~13%时,催化剂表现出较好的活性;随Mg含量的增加,反应活性基本呈下降趋势,说明Mg降低了催化剂体系的反应性能;Ce的加入总体上提高了反应活性,但是当Ce含量为3%时,反应活性最好;从不经预还原实验和低温点反应实验推断出,CH4和CO2重整反应中关键反应步骤是CH4的裂解;助剂Ce有利于提高催化剂的稳定性,而Mg却会使催化剂的稳定性下降很快。     

SiO_2表面环氧改性及其吸附天然胶乳中蛋白质的研究

用带有环氧基的硅烷偶联剂KH-560对SiO2粒子进行表面修饰改性,并用其对天然胶乳中的蛋白质进行吸附分离。结果表明,KH-560通过化学键牢固地结合在SiO2粒子表面,并通过环氧基与蛋白质反应,达到降低天然胶乳氮含量的目的。当pH=8~9,改性SiO2粒子的质量分数为1%,处理时间为6 h时,胶乳中氮含量(质量分数)降低到0.229 3%。     

酸洗脱灰对准东次烟煤结构和反应活性的影响

研究酸洗脱灰过程对煤的化学结构和反应活性的影响对煤的清洁高效利用十分重要。采用HCl-HF-HCl和HF-HNO₃-HCl两种方法对准东次烟煤进行处理,利用傅里叶红外光谱对原煤及其酸洗处理得到的脱灰煤进行结构表征,并用微型流化床多阶段气固反应分析仪对煤粉样品燃烧反应性进行分析。结果表明,酸洗处理可使煤中灰分含量降低到0.2%以下,脱灰煤中OH和COOH附近的吸收峰强度显著增强,脂肪侧链变短,芳香环上取代基减少。HF使得煤中硅铝类矿物质被大量脱除,HNO₃会与煤中有机物发生硝化反应,导致部分含氧官能团含量进一步增加。当温度在600和700℃时,脱灰煤燃烧反应性与原煤相比显著降低,但随着温度升高至800和900℃,脱灰煤与原煤的反应性差距变小。     

不同硫化助剂对CM/NR共混物性能的影响

研究了在过氧化物/PDM和过氧化物/硫黄复配硫化体系中,PDM和硫黄用量对CM/NR共混物性能的影响。结果表明,过氧化物/PDM复配硫化体系中,随着PDM用量增加,CM/NR共混物的t90和（MH-ML）的值都呈增大趋势,t10则呈减小趋势,当PDM用量为0.5～1.5份时,胶料有较好的物理综合性能。在过氧化物/硫黄复配硫化体系中,随着硫黄用量增加,CM/NR共混物的焦烧时间、正硫化时间呈减小趋势,当硫黄用量为0.6～1.2份时,胶料有较好的物理综合性能。     

Synthesis of high carbon content microspheres using 2-step microwave carbonization,and the influence of nitrogen doping on catalytic activity

In the present work, nitrogen-containing carbon particles were synthesized by a two-step microwave carbonization. Nitrogen was introduced into the carbon particles via the addition of urea solution during microwave-assisted hydrothermal carbonization. The nitrogen content was easily controlled by varying the urea concentration. Carbon microspheres of over 90% carbon content by atomic ratio were obtained using the microwave-assisted hydrothermal carbonization of glucose solutions, followed by the secondary microwave treatment of the dried samples. The effects of further microwave irradiation on the oxygen reduction reaction catalytic activity of nitrogen containing carbon particles were studied. This study showed that microwave-assisted hydrothermal carbonization, followed by additional microwave treatment can produce oxygen reduction reaction catalytic active carbon materials which contain nitrogen as catalytic active sites in conducting hexagonal layers of carbon structures. It is meaningful that carbon materials are obtained from environmental friendly starting materials biomass derivatives, under mild reaction condition.     

Evaluation of production yield and thermal processing of switchgrass as a bio-energy crop for the Mediterranean region

Switchgrass, a warm-season perennial grass, could play an important role for Europe in supplying sustainably produced lignocellulosic biomass, as its establishment cost is low and its productivity high under low input conditions. The aim of this study was to evaluate the adaptability and biomass productivity of switchgrass under the Greek climatic conditions and furthermore its suitability for heat and electricity applications, by performing fuel analyses, pyrolysis and combustion tests. Three-year field trials with different irrigation and fertilization levels showed that each level of irrigation had a significant effect on dry matter yields, while nitrogen effect was not pronounced. Yields were similar in the second and third year and ranged from 15.4% to 24 tons/ha.Fuel characterization showed a high volatile content and calorific value, whereas low ash, sulphur, nitrogen and chlorine contents. Ashes were rich in Si, K and P and some micronutrients, such as Zn. The ash fusion temperatures of the stems, which were richer in alkali, were low for combustion processes, revealing slagging/fouling problems in boilers without crop pre-treatment. However, their ash content was very low. The thermochemical reactivity of the stems was higher than that of the leaves, especially in air. The greater amount of minerals in the leaves inhibited the reaction rates in either nitrogen or air atmospheres. A first-order parallel reactions model for pyrolysis and a power low model for combustion fitted the experimental results accurately and kinetic parameters were derived. Irrigation/fertilization treatment had a positive effect on the combustion performance of the stems.     

Cyanoethylation of Hydroxyethyl Cellulose: Preparation and Characterization

Commercial hydroxyethyl cellulose (HEC) was cyanoethylated with acrylonitrile in nonaqueous medium in the presence of sodium hydroxide under a variety of conditions. Variables studied included the amount of acrylonitrile and the reaction temperature. The reaction was proved by NMR and its extent was measured by determining the nitrogen content. The physical properties of the obtained derivatives—i.e., the electric properties and the apparent viscosity at various rates of shear—were investigated. It was found that the extent of reaction was increased by increasing the amount of acrylonitrile as well as the reaction temperature. The products were water soluble and their apparent viscosity increased with increasing nitrogen content. The same holds true for the dielectric constant and dielectric loss.     

Fabric properties of butadienediepoxide-treated cottons as affected by liquid ammonia pretreatments

Effects of liquid ammonia and mercerizing-strength caustic as pretreatments upon textile properties of cotton sheeting modified with butadienediepoxide (BDO) catalyzed by 2% and 15% NaOH were compared. Tensile properties of the NaOH-mercerized control (CM) (celluloses I and II) greatly exceeded those of native (cellulose I) and ammonia-treated (NH₃) controls. NH₃(I) and NH₃(III) are those cottons having the cellulose I and mixed cellulose I and III lattices, respectively. Resistance to flex abrasion was doubled by pretreatments. Wrinkle recoveries of all controls were equivalent, but tensile recovery differed. BDO reaction enhanced wrinkle recovery of controls but produced the usual losses in tensile properties and resistance to flex abrasion associated with crosslinking reagents. BDO reaction nullified the initial tensile advantage held by CM cotton. Tear strengths of all BDO-treated cottons remained comparable. High dry and high wet recoveries were obtained only when 2% NaOH catalyzed the BDO reaction and were greatest for NH₃ cottons. BDO reaction reduced permanent set of all controls and increased tensile recovery primarily by enlarging the delayed recovery. Postmercerization with 23% NaOH adversely affected recovery behavior of all BDO-treated cottons. Nevertheless, wrinkle and tensile recoveries of postmercerized NH₃(I) and CM cottons were equivalent. Postmercerization partially restored fabric properties of BDO cottons with cellulose I lattice to those of their respective controls; no change was noted for corresponding products from CM cottons. Because of this, final properties of products from NH₃(I) cottons equaled and even exceeded those of comparable CM cottons.