工艺因素对木质纤维素苯酚液化残渣率的影响

为提高木质包装废弃物的利用率和附加值,拓宽木质资源的应用途径,研究了液固比(苯酚/纤维素)、催化剂含量、液化温度及反应时间对木质纤维素液化产物的影响。结果表明:随着液化温度的升高,木质纤维素液化物的残渣率先下降后增大,160℃时残渣率达到最低;随着催化剂含量的提高,木质纤维素液化的残渣率呈下降趋势,当催化剂含量低于6%时,残渣率下降较明显;液固比(苯酚/纤维素)小于5∶1时,木质纤维素液化的残渣率下降较明显;反应时间的增加对木质纤维素液化的残渣率的贡献率逐渐降低。     

不同碳源制备碳基固体酸及其在水解纤维素中的应用

采用磁性碳纳米管(CNTs)、葡萄糖、炼焦酚渣为碳源,制得碳基固体酸催化剂.通过XRD、FTIR、13C NMR和SEM/TEM对其结构和活性基团进行表征,并且以经过预处理的微晶纤维素为纤维素模型物,以总还原糖得率为考察指标,利用制备的碳基固体酸非均相催化水解纤维素,比较了3种碳源制得的碳基固体酸在水解纤维素中的水解效率.研究结果表明,与传统原料葡萄糖制得的碳基固体酸相比,酚渣基固体酸碳环上除了含有酚羟基、羧基和磺酸基外,还含有其它碳基固体酸不具备的烷基侧链,这一结构优势对碳基固体酸催化剂的催化活性具有促进作用,能够提高碳基固体酸催化剂的水解效率;碳纳米管固体酸尽管具有致密的碳层结构、磺化后磺酸密度低,但高比表面积使其在非均相催化水解纤维素中表现出较高的活性.     

纤维素的功能材料

纤维素是地球上最为丰富的可再生资源，既可收获又能再生，而且具有价廉，可降解性和对生态环境不产生污染等优点，因而，自本世纪70年代以来，纤维素功能材料的研制与开发一直保持向上发展的良好趋势，并在多数工业化国家实现工业化，本文着重介绍自80年代以来纤维素，纤维素衍生物以及木质纤维素的功能材料，诸如吸水，吸油，吸重金属离子和特种物质的吸附材料；热塑性与液化木质纤维素材料，以及生物活性材料之新近进展。     

沙生灌木基生物质材料研究进展与发展趋势

沙生灌木是我国西部干旱、半干旱地区丰富的生物质资源，以其抗旱、抗寒、生长快等优点在防风固沙和水土保持方面对生态保护与荒漠化治理具有重要意义。基于此，围绕沙生灌木资源的生物质资源属性，系统总结了近年来沙生灌木资源在木质复合材料、生物质活性炭材料、木质资源液化物和生物质炭材料等领域的研发现状。结果表明，现有丰富的研究成果已充分证实了沙生灌木资源在上述生物质材料领域应用的巨大潜力。然而在纳米纤维素、生物质炭材料等领域尚存在研究成果不够丰富、研发技术不够成熟，相关技术水平不够先进的现实问题。最后，在拓宽沙生灌木资源种类、提升沙生灌木基生物质材料附加值以及加大沙生灌木基生物质材料高附加值关键科学技术转化进程等方面提出了研究展望，旨在为进一步提高沙生灌木资源的高效利用提供科学依据。     

橡胶籽壳无机-有机催化液化及产物的结构表征

以苯酚为液化剂,对橡胶籽壳进行了液化,分析了反应温度,液料比(苯酚与橡胶籽壳的比),催化剂的种类和用量及液化时间对液化反应的影响,同时利用响应曲面设计进行了优化。结果表明:采用V(硫酸)∶m(对甲苯磺酸)=1∶1为催化剂,在反应时间84min,液料比4.0∶1mL/g,液化温度155℃,催化剂的用量为8%时,残渣率为0.48%,液化率为99.52%,几乎完全液化。FTIR分析表明,橡胶籽壳在苯酚的作用下发生了化学反应,致使分子组成(纤维素,半纤维素,木质素等)发生了变化,生成了具有活性官能团的醇类以及酚类物质,同时,伴有新的化合物的生成。     

无机固体碱催化剂的研究进展

本文介绍了固体碱性催化剂,特别是无机固体碱性催化剂的特点、分类。由于无机固体碱性催化剂具有的独特的优点和发展前景,受到广泛重视。文中按金属氧化物型、稀土金属氧化物型、复合金属氧化物型和载体型（惰性和半导体性）固体碱进行了分类,并分别进行了讨论。在文章最后部分还对纳米型催化剂作了简要的论述,指出了纳米催化剂的特点和优势。     

木质纤维素基高分子材料的研究进展

木质纤维素现已成为制备高分子材料的重要原料。木质纤维素可以用作高分子复合材料中的增强剂或填料;木质纤维素经液化进行适度降解,再与其它物质进一步反应,可以制备聚氨酯、环氧树脂、酚醛树脂等高分子材料;经过适当的化学处理制备纺丝液,利用熔融纺丝技术纺丝再通过炭化处理可以制得炭纤维;浸渍热固性树脂后,在隔绝空气的条件下,高温炭化可以制得木质陶瓷;经组分分离和双亲改性后,使用化学交联剂交联可以制备水凝胶。     

制备生物柴油负载型固体催化剂的研究进展

非均相催化剂的研制一直是生物柴油领域的研究热点,而其中的负载型催化剂以其制备材料广、活性高、重复利用性好等优点成为生物柴油制备的首选催化剂。本研究综述了以金属氧化物及复合物、活性炭和分子筛为主要载体的负载型固体酸碱催化剂最新研究进展,包括催化剂的制备、催化性能和存在的问题。最后,展望了负载型固体催化剂在生物柴油产业的应用前景。     

木质导热复合材料的传热增强机理及制备研究进展

木质导热复合材料是以不同几何尺度的木质单元为基体,以不同加工工艺引入导热单元后制得的一种导热性能增强的复合材料.木质导热复合材料具有较高的导热系数,可将热量迅速传递及辐射至周围环境中,若将其应用于地采暖地板、导热装饰木制品等家装领域,不仅可以充分利用天然可再生木质资源具有的质轻、易加工、经济环保等优点,减少不可再生资源...     

低共熔溶剂体系下木质纤维素的功能化改性及应用研究进展

低共熔溶剂(DES)作为一种新型绿色溶剂,相比离子液体等其它溶剂,其具有制备简单、配制灵活、成本低、效率高等特点,在木质纤维素绿色加工领域有着广泛的应用前景。近年来,基于DES体系下木质纤维素的溶解、组分分离、衍生化改性等研究取得了一系列重要的进展,相比于在传统离子液体或有机溶剂体系,在DES体系下木质纤维素的化学改性更绿色环保,经过改性的木质纤维素在纳米纤维的制备、复合材料的构建等领域得到了广泛的应用。本文综述了在DES体系下木质纤维素的阳离子化、酯化及其它衍生化等功能化改性及DES体系下改性的木质纤维素在纳米分散、复合材料等功能化应用方面的研究进展。最后总结并展望了在DES体系下木质纤维素功能化改性及应用所面临的机遇和挑战。      

木质素催化降解液化的研究进展

木质素是自然界中含量仅次于纤维素的天然有机高分子,它是以3种苯丙烷(芥子醇、松柏醇和香豆醇)为结构单元,通过C-C和C-O-C键连接形成的无定形网状大分子,是自然界唯一可再生的芳香类物质原料。木质素在生产大宗化学品和精细化学品方面有着巨大潜力。但是,木质素复杂的结构导致其难以高效、高选择性转化而被有效利用。近年来,有关木质素催化降解液化的研究成为一个备受关注的热点。概述了木质素催化降解液化的研究现状,基于溶液状态下木质素分子尺度和形态分析,设计与之匹配的负载酸和金属粒子的介孔催化剂,可实现木质素在有限孔道内催化降解以及抑制降解片段重聚,最后对其未来发展趋势进行了展望。     

一类新型碱激发胶凝材料催化剂的研究进展

碱激发固体铝硅酸盐胶凝材料是先进无机非金属材料的前瞻性研究领域之一, 本文对碱激发铝硅酸盐胶凝材料的分类、制备工艺、形成机理以及潜在的应用前景进行了综述; 详尽地论述了碱激发胶凝材料基新型催化剂的最新研究进展, 综合分析了碱激发胶凝材料作为结构材料研究的局限性, 展望了该材料作为新型催化材料的发展动态。     

Preparation of mesoporous titania solid superacid and its catalytic property

Mesoporous titania (TiO(2)) was synthesized by hydrothermal method using cetyltrimethyl ammonium bromide (CTAB) as a template and using anhydrous ethanol and tetra-n-butyl titanate (TBOT) as raw materials. Mesoporous titania solid superacid and nanosized titania solid superacid catalysts were prepared by wet impregnation method. The structure and property of as-prepared samples were characterized by means of XRD, FT-IR and N(2) physical adsorption. The esterification of salicylic acid with isoamyl alcohol and the condensation of cyclohexanone with ethylene were used as model reactions to test the catalytic activities of the catalysts. On the other hand, the comparison of catalytic activities of the prepared solid superacid catalysts and the conventional liquid acid H(2)SO(4) was also carried out under the same experimental conditions. The results show that the catalytic activities of the prepared solid superacid catalysts were higher than that of the conventional liquid acid H(2)SO(4), and that the catalytic activity of mesoporous TiO(2) solid superacid is the highest among the three catalysts. Mesoporous TiO(2) solid superacid is a good catalyst for the synthesis of isoamyl salicylate or cyclohexanone ethylene ketal.     

Role of clay as catalyst in Friedel–Craft alkylation

Solid acids have become increasingly important for many liquid-phase industrial reactions these days. Montmorillonite clays (2:1 clay mineral) have been used as efficient solid acid catalysts for a number of organic and liquid phase reactions and offer several advantages over classic acids. Tailor made catalysts can be prepared from clays by suitably adjusting their acidity and surface area by acid activation. In the present work, preparation, characterization and performance of Pt (II) clays, Cu (II) clays, acid clay, and sol–gel hybrids of Cu (II) clays as solid catalysts in a test Friedel–Craft alkylation reaction of benzyl chloride with toluene using differential scanning calorimeter (DSC) are reported. Product formation has been analysed by FTIR spectroscopy. The main objective of this work is to show how clay as a solid catalyst affects reaction rates and activation energies. Acidity and dispersion of solid catalysts are two main factors which govern a catalysis reaction. Kinetic parameter analysis and XRD studies confirm that acid Pt (II) clay and Pt (II) clay dispersed by natural dispersants are more effective catalysts. In contrast to the reactions using AlCl₃, the experimental conditions are non-polluting and the final work up does not require any aqueous treatment.     

SO_4~(2-)/ZrO_2型固体超强酸改性及其催化氧化脱除噻吩类硫化物

通过掺杂不同金属元素对SO_4~(2-)/ZrO_2型固体超强酸进行改性,应用共沉淀法制备了一系列固体酸催化剂SO_4~(2-)/ZrO_2、SO_4~(2-)/ZrO_2-ZnO、SO_4~(2-)/ZrO_2-Fe_2O_3、SO_4~(2-)/ZrO_2-CuO、SO_4~(2-)/ZrO_2-Al_2O_3,利用氧气作氧化剂进行催化氧化脱除噻吩硫化物动力学实验.研究结果表明,掺杂了Zn、Fe和Cu的SO_4~(2-)/ZrO_22型催化剂催化氧化效果较SO_4~(2-)/ZrO_2都有明显提高,其中添加了金属Zn的SO_4~(2-)/ZrO_2-ZnO催化氧化效果最好,在反应温度为50℃,能达到100%的脱硫率.对合成的系列固体酸进行了X射线衍射(XRD)、氨程序升温脱附(NH3-TPD)的表征,结果表明,催化剂样品中四方相ZrO_2的含量越高,表面酸含量越大,其催化氧化噻吩硫化物的活性越高.     

PEO类聚合物基体的改性及其高性能电解质材料研究的新进展

聚氧化乙烯(PEO)是聚合物电解质传统的基体材料,它最大的优势在于在不添加任何增塑剂的情况下,可以与锂盐形成稳定的络合物,但PEO易于结晶,使离子电导率降低。研究表明:采用共混、接枝、共聚、交联以及与无机物复合等方法对PEO进行改性,可以进一步提高此类聚合物电解质的性能。重点对PEO类聚合物基体的改性及其高性能固体聚合物电解质材料研究的新进展进行介绍,并对其研究前景做了展望。     

Bioleaching of spent hydro-processing catalyst using acidophilic bacteria and its kinetics aspect

Bioleaching of metals from hazardous spent hydro-processing catalysts was attempted in the second stage after growing the bacteria with sulfur in the first stage. The first stage involved transformation of elemental sulfur particles to sulfuric acid through an oxidation process by acidophilic bacteria. In the second stage, the acidic medium was utilized for the leaching process. Nickel, vanadium and molybdenum contained within spent catalyst were leached from the solid materials to liquid medium by the action of sulfuric acid that was produced by acidophilic leaching bacteria. Experiments were conducted varying the reaction time, amount of spent catalysts, amount of elemental sulfur and temperature. At 50 g/L spent catalyst concentration and 20 g/L elemental sulfur, 88.3% Ni, 46.3% Mo, and 94.8% V were recovered after 7 days. Chemical leaching with commercial sulfuric acid of the similar amount that produced by bacteria was compared. Thermodynamic parameters were calculated and the nature of reaction was found to be exothermic. Leaching kinetics of the metals was represented by different reaction kinetic equations, however, only diffusion controlled model showed the best correlation here. During the whole process Mo showed low dissolution because of substantiate precipitation with leach residues as MoO3. Bioleach residues were characterized by EDX and XRD.     

Effect of hydrometallurgical process parameters on the Mn2O3 nano catalysts derived from spent batteries used in the plasma catalytic oxidation of BTX

Manganese oxide catalysts have been synthesized from the used batteries via hydrometallurgical method and effect of hydrometallurgical parameters such as the effect of acid type (H₂SO₄, HNO₃, HCl), acid concentration (0.5, 1, 1.5, 2 %v/v) and powder to acid ratio (1/50, 1/60, 1/70, 1/80) were in detail investigated. The physico-chemical properties of as-prepared catalysts were characterized by FT-IR, XRD, FESEM, EDX, BET, TEM, and TPR-H₂ analysis. The activity of as-prepared catalysts were investigated towards the oxidation of benzene, toluene, and xylene (BTX) in a plasma-catalytic process. The results show that benzene and toluene conversion were almost constant in the range of 97–98% in case of various acid types, acid concentrations and solid to liquid ratios. However, the xylene conversion were varied in case of different hydrometallurgical factors. The highest xylene conversion was obtained in the presence of MnS0.5–60, which was prepared using H₂SO₄ with concentration of 0.5%v/v and solid to liquid ratio of 1/60. The effect of the input voltage and BTX flow rate on the BTX conversion was also investigated using MnS0.5–60 catalyst in detail.     

质子交换膜掺杂固体无机质子导体材料的研究进展

主要介绍了目前掺杂质子交换膜用的几种无机质子导体磷酸锆、杂多酸、硫酸氢盐等,并进一步介绍了将这些无机质子导体引入到聚合物中的3种掺杂方法:混合浇铸法、离子-沉淀法和溶胶-凝胶法.重点介绍了国内外掺杂无机固体质子导体的燃料电池用质子交换膜的研究进展.