Separation of liquefied product of Salix psammophila by column chromatography and structure analysis of its components

The liquefied product of Salixpsammophila wood was separated by thin-layer chromatography （TLC） and column chromatography, and its structure was identified by nuclear magnetic resonance （NMR） spectra in our study. The separation result indicates that the sample of liquefied S. psammophila contained at least two categories of components. The structure of the main components was guaiacyl C-1, C-2 of the hydroxyphenyl propane, i.e., the aromatic nucleus protons of lignin. Degradation and polycondensation reactions occurred when the S. psammophila wood was liquefied in phenol. Polycondensation reactions occurred among the depolymerization products from cellulose, the aromatic depolymerization products from lignin and the products of the displacement reactions between phenoxide ion and cellulose.     

Analysis on residue formation during wood liquefaction with polyhydric alcohol

Liquefactions of cellulose powder, steamed lignin, alkali lignin, and their mixtures were carried out to analyze the reaction process of wood using polyhydric alcohol. The liquefaction of wood proceeded immediately and wood components were converted to N,N-dimethylformamide (DMF)-soluble components. After that, the condensation reaction occurred with increasing reaction time. However, none of cellulose powder, steamed lignin, and alkali lignin condensed by themselves during their liquefaction. The mixture of cellulose and lignin was also liquefied, and condensed after a long reaction time. The results of analysis showed that the behavior of the mixture resembled that of wood with respect to molecular weight distribution and the main functional groups. Lignin was converted to DMF-soluble compounds in the initial stage of wood liquefaction, followed by cellulose gradually being converted into soluble compounds. After that, condensation reactions took place among some parts of depolymerized and degraded compounds from cellulose and lignin, and were converted into DMF-insoluble compounds. It was concluded that the rate-determining step of wood liquefaction was the depolymerization of cellulose. Furthermore, it was suggested that the condensation reaction was due to the mutual reaction among depolymerized cellulose and degraded aromatic derivatives from lignin or due to the nucleophilic displacement reaction of cellulose by phenoxide ion.Part of this report was presented at the 52nd Annual Meeting of the Japan Wood Research Society, Gifu, April 2002     

木粉及其组分的多元醇酸催化热化学液化

分别将木粉、纤维素和木质素在乙二醇中进行热化学液化。研究结果表明木粉中纤维素的非结晶区、木质素和半纤维素首先被液化,而纤维素的结晶区较慢被液化,到液化反应中期基本降解完全,液化产率高于97%。利用在线红外光谱仪跟踪检测了整个液化反应过程,结合GC-MS结果发现:乙二醇在反应过程中脱水生成了二甘醇和三甘醇。在液化反应中,纤维素的糖苷键断裂后生成葡萄糖苷结构,随后葡萄糖苷中的吡喃环也被打开,生成的活性中间体相互反应或与乙二醇反应生成了如3-(2-甲基-[1,3]-二氧戊环-2-基)-丙酸乙酯、乙酰丙酸丁酯等酯类;木质素的苯丙烷结构主要降解为苯酚、2,6-甲氧基苯酚等芳香族衍生物,因此木粉液化产物是聚醚/酯混合多元醇。     

Effect of ozone treatment of wood on its liquefaction

The effects of ozone treatment were investigated to improve the process of liquefaction of wood with polyhydric alcohol solvents. The liquefied wood having a high wood to polyhydric alcohol ratio (W/P ratio) could be prepared by using the wood treated with ozone in the liquid phase. The liquefied wood with a W/P ratio of 2 : 1 had enough fluidity to act as a raw material for chemical products. To get some information about the effects of ozone treatment toward the wood components, cellulose powder and steamed lignin were treated with ozone and liquefied. In particular, ozone treatment in the liquid phase was found to be effective for wood and cellulose powder. On the other hand, steamed lignin self-condensed during liquefaction after treatment with ozone in the liquid phase. Thus, ozone treatment provided lignin with reactive functional groups, and caused the subsequent condensation reaction. Although lignin was converted to a more condensable structure by ozone treatment, the condensation reaction was found to be suppressed for wood during its liquefaction. The wood liquefied products displayed good solubilities in N,N-dimethyl formamide (DMF) even after treatments of long duration. It was suggested that one of the main effects of ozone treatment toward wood was the decomposition of cellulose.Part of this report was presented at the 53rd Annual Meeting of the Japan Wood Research Society, Fukuoka, April 2003     

Preparation and Characterization of the Phenolated Wood Using Sulfuric Acid as a Catalyst Ⅱ. FT-IR and GPC Characterization

By means of gel permeation chromatography analysis, the molecular weight of liquefied wood under different reaction conditions was investigated to trace the change in the structural characteristics of the liquefied wood. The insoluble residues were analyzed by Fourier transform infrared to investigate the liquefaction order of three main wood components. The results indicate that both reaction temperature and reaction time could affect the molecular characteristics of the liquefied wood obtained. The molecular weight of liquefied Chinese Fir wood is higher than that of liquefied Poplar wood under most of reaction conditions. During wood liquefaction, lignin is liquefied firstly. Hemicellulose is liquefied in the middle stage and cellulose is the most difficult to be liquefied.     

木质纤维素及其组分转化木材胶粘剂的发展趋势

木质素是造纸工业废液中的主要成分。其具有和酚醛树脂相似的结构, 因此可以部分替代苯酚用于酚醛树脂的生产。但是由于木质素化学结构复杂, 具有化学反应活性的位点少、反应官能团所收到的空间位阻大, 一般添加量不超过10%~20%。有机溶剂法制浆分离的木质素分子量大, 纯度高, 酚醛树脂允许的添加量可达20%~30%, 但是要求提高固化温度、延长固化时间来克服木质素反应活性低的限制。对木质素进行化学改性如羟甲基化、酚解、醇解、还原等, 可以降低分子量, 增加活性基团如酚羟基的含量、并使苯环上更多的活性位点暴露出来, 从而提高木质素的化学反应活性。酚醛树脂经过改性木质素的允许的添加量可达30%~40%。部分木质素含量高的木质纤维素类原料如核桃壳粉等, 经过研磨和化学活化处理后可以直接添加到酚醛树脂中, 部分替代苯酚而不对胶接性能产生影响。环碳酸酯类和多元醇混合物被用来作为全新的液化剂来把木质纤维素快速液化为有用的化学原料。所得到的液化产物具有较高的反应活性, 是今后利用木质纤维素开发绿色木材胶粘剂的一条可资利用的途径。     

Reaction behavior of wood in an ionic liquid, 1-ethyl-3-methylimidazolium chloride

Reaction of Japanese beech (Fagus crenata) in an ionic liquid, 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), which can dissolve cellulose, was investigated. Although both lignin and polysaccharides such as cellulose and hemicelluloses can be liquefied at a treatment temperature of around 100°C, the liquefaction of polysaccharides mainly occurs at the beginning of the treatment with [C2mim][Cl]. Cellulose crystallinity in the wood was gradually broken down as the treatment continued. The solubilized polymers were depolymerized to low molecular weight compounds. The results indicate that [C2mim][Cl] is an effective solvent and reagent for the liquefaction of wood components and subsequent depolymerization of them. Part of this report was presented at the 58th Annual Meeting of the Japan Wood Research Society, Tsukuba, April 2008     

用FTIR法研究木材阻燃剂FRW的阻燃机理

采用FTIR显微分析技术,对FRW阻燃处理红松木材限制燃烧固相产物的结构进行分析;采用GC_FTIR联机分析方法,对经FRW阻燃剂及其主要组分处理的紫椴木材试样的热解挥发性产物进行分析和鉴定;讨论FRW阻燃处理木材的热解炭化过程、阻燃剂的作用以及热解产物的结构特点。结果表明:FRW阻燃木材受热时,随着温度的升高,在FRW及其分解产物的催化下,木材逐步发生聚糖脱水、半纤维素脱乙酸、聚糖降解、木质素降解、木材热解产物聚合、脂肪族聚合物脱氧及芳构化等反应,最终炭化;FRW阻燃剂改变了木材的热解途径,并且显著降低了挥发性有机化合物的生成量。     

Liquefaction and FTIR analysis of two desert shrubs Salix psammophila and Caragana intermedia

1 Introduction Desert shrubs are made up of natural composite mate- rials, composed of cellulose, hemicellulose and lignin. Although there are a large number of hydroxyl groups in them, these are not fully used due to the high crys- tallinity of cellulose and tight interconnection among polymeric components in wood (Cheng et al., 2002). Liquefaction of wood is a new technique in wood in- dustries. It is a novel process which effectively con- verts the chemical composition of wood into macro- …     

Two-step hydrolysis of Japanese cedar as treated by semi-flow hot-compressed water

Two-step hydrolysis of Japanese cedar (Cryptomeria japonica) was studied as treated by semi-flow hot-compressed water at 230°C/10 MPa for 15 min and 280°C/10 MPa for 30 min as the first and second stages, respectively. At the first stage, hemicelluloses and para-crystalline cellulose, whose crystalline structure is somewhat disordered, were found to be selectively hydrolyzed, as well as lignin decomposition, whereas crystalline cellulose occurred at the second stage. In all, 87.76% of Japanese cedar could be liquefied by hot-compressed water and was primarily recovered as various hydrolyzed products, dehydrated, fragmented, and isomerized compounds as well as organic acids in the water-soluble portion. The remainder, 12.24%, could not be hydrolyzed and remained as the water-insoluble residue composed entirely of lignin. Based on the distribution of various products from hemicelluloses in Japanese cedar, their decomposition pathways were proposed as independent.     

Formation and chemical structures of acid-soluble lignin I: sulfuric acid treatment time and acid-soluble lignin content of hardwood

To elucidate the formation mechanism of acidsoluble lignin (ASL) formed in the Klason lignin determination, beech wood meals were treated with sulfuric acid (SA) under various conditions, and the ASL solution was extracted with CHC1₃. The results indicated the following: (1) wood components yielding ASL are dissolved in 72% SA during the initial stage; (2) the quantity of ASL is highest during the initial stage, then decreases with prolonged time of 72% SA treatment and finally reaches a constant value; (3) soluble lignin prepared by 72% SA treatment and subsequent standing in 3% SA again yield insoluble Klason lignin and ASL after boiling in 3% SA; and (4) about half the amount of ASL is dissolved in CHC1₃. The foregoing suggest that wood components yielding ASL are dissolved in 72% SA at the beginning and finally change to ASL after being subjected to depolymerization, hydrolysis, and other reactions. ASL may thus be composed of low-molecular-weight degradation products and hydrophilic derivatives of lignin.     

徐州出土汉代棺木用材树种鉴定及其化学性质

木材是人类日常生活的常见材料,也是从古至今人类文明与民族文化的重要载体。伴随着考古发掘工作的进行,来自不同地区、不同朝代的大量木质文物出土并需要持续保护,因此掌握出土木质文物所用的木材树种情况,并研究其化学组分的降解状态,可为制定合理的木质文物修复和保护方案提供科学依据。通过对徐州万达汉墓墓群中1号与4号墓出土棺木进行取样和对标准三切面的切片进行观察,根据三切面显微构造特征对棺木所用木材树种进行鉴定,经与标准切片比对,结果表明M1c、M1oc、M4c、M4oc棺木树种分别为楠木(Phoebe sp.)、硬木松(Pinus sp.)、梓木(Catalpa sp.)、榉木(Zelkova sp.)。进一步采用荧光显微镜与傅里叶变换红外光谱、X射线衍射相结合的方法,分析棺木的主要化学组分降解情况。结果表明:与现代健康材相比,古木在长期埋藏过程中,木材的主要多糖类化学组分纤维素和半纤维素降解严重,纤维素结晶度降低;古木各类型细胞中木质素的自发荧光效应均减弱,且红外光谱分析表明木质素化学结构发生改变;古木在埋藏过程中木材的整体构造保存较好,但主要化学组分发生了降解,这与其地下饱水低氧的埋藏环境有很大关系。     

竹材酚醇液化及其应用研究进展

竹材酚醇液化是竹材综合利用的有效方法之一,通过溶剂反应破坏竹材纤维素的结晶结构、半纤维素和木质素高分子结构,使其分子链断裂,降解成带有反应活性的羟基化合物,可以用于制作胶黏剂、发泡材料和碳纤维等。文章分析了竹材液化原理、酚醇液化技术,以及竹材酚醇液化产物的应用研究现状,认为该领域今后需要加强基础理论和预处理技术的研究,尽快制定相关产品标准,实现竹材资源的高利用率和高附加值。     

木材白腐机理研究进展

白腐菌是木材的主要腐朽菌之一，白腐菌菌丝在细胞内形成多种降解酶主要是木素降解酶，次则是纤维素降解酶及半纤维素降解酶，以降解细胞壁物质中的木素、半纤维素及纤维素，作为木腐菌的营养。由于这些木材组成的降解，必然改变木材的化学及物理性质。近年来，在白腐菌的营养需求、降解酶传递途径，对木材主要组成酶降解机理及对材性的影响，产酶的分子遗传等领域的研究均取得一定进展，可望不久将来能利用生物工程改变白腐菌基因，     

Reaction behavior of wood in an ionic liquid, 1-ethylpyridinium bromide

The reactions of Japanese cedar and Japanese beech in a pyridinium-based ionic liquid, 1-ethylpyridinium bromide ([EtPy][Br]) were studied. Japanese beech was more easily liquefied than Japanese cedar. Hemicellulose is liquefied rapidly, lignin more slowly, while cellulose is partially liquefied. X-ray diffraction analyses on the [EtPy][Br]-insoluble residues revealed that the crystalline structure of cellulose is maintained even after treatment. The difference in liquefaction can be explained by chemical structural differences between softwood and hardwood lignins and hemicelluloses.     

杨木应拉木微区结构可视化及化学成分分析

木材微区结构与木材宏观性质密切相关,杨木应拉木与对应木宏观性质存在较大差别,探究杨木应拉木和对应木微区结构和化学成分,可为了解杨木应力木的宏观性质提供理论根据。借助光学显微镜、荧光显微镜、显微拉曼成像光谱仪、透射电镜对杨木应拉木微区结构进行可视化研究,并借助X射线衍射技术和美国可再生能源实验室方法,分析杨木应拉木的微晶尺寸、结晶度以及化学成分。结果表明:杨木应拉木中应拉区和对应区纤维细胞微区结构差异显著。光学显微镜下显示应拉区木纤维中胶质层清晰可见,荧光显微镜和拉曼显微镜下显示胶质层的木质素浓度比对应区低。透射电镜下显示应拉区木纤维细胞壁结构由初生壁、次生壁和胶质层组成,未见次生壁外层,各层的平均厚度分别为0.61,1.22和2.53μm。对应区木纤维为典型的初生壁和次生壁结构,次生壁各层平均厚度分别为0.33,2.28和0.14μm。杨木应拉区纤维素含量(58.91%)比对应区(41.53%)高,木质素含量和半纤维素含量均比对应区的低,应拉区木质素和半纤维素含量分别为21.99%和12.01%,对应区分别为28.10%和17.08%。杨木应拉区结晶度(48.06%)比对应区(41.01%)高,应拉区晶区宽度为2.66 nm,长度为8.84 nm;对应区晶区宽度为2.65 nm,长度为9.87 nm。     

Liquefaction and product identification of main chemical compositions of wood in phenol

To clarify liquefaction ratios and their construction variations of the main chemical compositions of wood in phenol using phosphoric acid as a catalyst, the chemical ingredients of wood such as holocellulose, cellulose and lignin, were measured and extracted according to GB methods. With Fourier transform infrared （FTIR）, the product identification of reactant before and after liquefaction in phenol was investigated. The molecular weights and their distributions of the liquefaction results （acetone soluble parts） were studied by gel permeation chromatography （GPC）. Results show that the molecular weights and their distributions of poplar and Chinese fir are almost the same. In poplar, the distribution of cellulose is the largest, and that ofholocellulose the smallest after liquefaction. For Chinese fir, the distribution of holocellulose is the largest, and that of cellulose the smallest. After liquefaction of poplar cellulose, the change bands of FTIR spectrum observed below 1 600 cm^-1, can be attributed to new substitute groups. The same is true for poplar lignin. For Chinese fir, the spectra of liquefaction results of all chemical compositions differ from that of wood meal. This reveals the more activity groups were produced because of the reactions between Chinese fir and phenol. The research shows that the liquefaction ratios of poplar decrease in the following order： holocellulose 〉 lignin 〉 cellulose, and those of Chinese fir in the order： lignin 〉 cellulose 〉 holocellulose.     

木材表面非极性化原理的研究 I.木材乙酰化过程中化学官能团的变化

对杉木和“三北”一号杨两种木材的各主要组成进行了酯化处理,研究其在乙酰化过程中木材各主要组成的化学官能团的变化特征和结构的稳定性。结果表明：磨木木质素、纤维素、半纤维素经乙酸酐处理后,红外光谱上的１７４２ｃｍ－１附近均出现了表示酯类ＣＯ伸缩振动的新的吸收峰,表明在乙酰化过程中这些组分的化学结构都有新的非极性酯类化学官能团产生;而极性的羟基官能团的数量均有不同程度的减少;芳香基和脂肪基的结构上均有乙酸酯生成。纤维素酯化程度较低,半纤维素化学结构在乙酰化过程中会发生降解,而木质素和纤维素较为稳定。乙酰化处理是降低木材表面极性的一种有效方法。     

Fire-retardant mechanism of fire-retardant FRW by FTIR

The structures of the solid state products formed by the partial combustion of Korean pine wood treated with fire-retardant FRW were analyzed by microscopic FTIR. The volatile pyrolytic products of basswood (Tilia amurensis) specimens treated with FRW and its components guanylurea phosphate and boric acid were analyzed by GC-FTIR. The pyrolytic and charring process, the effects of fire-retardant, and the structural characteristics of the pyrolytic products were discussed. It was concluded that upon heating and by the catalysis of FRW and its decomposition products reactions of wood took place successively, namely the dehydration of polysaccharide, the elimination of acetic acid from hemicellulose, the degradation of polysaccharide, the degradation of lignin, the polymerization of the pyrolytic products of wood, reactions of oxygen-element-elimination of aliphatic polymers and the structural change of the latter to form aromatic structures, and charring. The pyrolysis process of wood was altered and the yield of volatile pyrolytic products was decreased by FRW treatment. __________ Translated from Scientia Silvae Sinicae, 2005, 41(4): 149–154 [译自: 林业科学, 2005, 41(4): 149–154]     

核桃壳胶粘剂化学背景的探讨

探讨漾濞泡核桃壳作木材胶粘剂原料的化学背景。化学分析结果表明:漾濞泡核桃壳中含(硝酸法)纤维素3 3 2 5 %、多戊糖2 6 72 %、木素6 0 94 %、灰分1 1 9%;核磁共振氢谱、紫外和红外光谱的分析结果表明:核桃壳木素以愈疮木基-紫丁香基木素为主,属GS型木素,且G型木素的含量大于S型木素。利用G型阔叶材木素的化学性质可以合成得到与普通酚醛树脂胶合性能相当的核桃壳木素-苯酚-甲醛共聚树脂。