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Chemical mechanism of fire retardance of boric acid on wood 总被引：5，自引：0，他引：5
It is commonly accepted that the fire retardant mechanism of boric acid is a physical mechanism achieved by the formation of a coating or protective layer on the wood surface at high temperature. Although a char-forming catalytic mechanism has been proposed by some researchers, little direct experimental support has been provided for such a chemical mechanism. In this paper, new experimental results using thermal analysis, cone calorimetry (CONE), and gas chromatography–Fourier transform infrared spectroscopy (GC–FTIR) analysis are presented and the fire retardant mechanism of boric acid on wood is discussed. Basswood was treated with boric acid, guanylurea phosphate (GUP), and GUP–boric acid. Treated wood was then analyzed by thermogravimetry (TG/DTG), differential thermal analysis (DTA), CONE, and GC–FTIR analysis. Thermogravimetry showed that the weight loss of basswood treated with boric acid was about three times that of untreated or GUP-treated wood at 165°C, a temperature at which GUP is stable. The DTA curve showed that boric acid treated basswood has an exothermal peak at 420°C, indicating the exothermal polymerization reaction of charring. CONE results showed that boric acid and GUP had a considerable synergistic fire retardant effect on wood. The GC–FTIR spectra indicated that compounds generated by boric acid treated wood are different than those generated by untreated wood. We conclude that boric acid catalyzes the dehydration and other oxygen-eliminating reactions of wood at a relatively low temperature (approximately 100–300°C) and may catalyze the isomerization of the newly formed polymeric materials by forming aromatic structures. This contributes partly to the effects of boric acid on promoting the charring and fire retardation of wood. The mechanism of the strong fire retardant synergism between boric acid and GUP is due to the different fire retardant mechanisms of boric acid and GUP and the different activation temperatures of these two chemicals.The Forest Products Laboratory is maintained in cooperation with the University of Wisconsin. This article was written and prepared by U.S. Government employees on official time, and it is therefore in the public domain and not subject to copyright. The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service. 相似文献
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茉莉酸甲酯和水杨酸甲酯诱导杨树叶片内酚酸含量的变化 总被引：2，自引：0，他引：2
用茉莉酸甲酯(MeJa)及水杨酸甲酯(MeSa)熏蒸合作杨(P.Simonii×P.Pyramibalis c.v)和黑杨(P.deltoids)植株,采用高效液相色谱技术(HPLC)检测杨树叶片内没什子酸、儿茶酸、邻苯二酚、咖啡酸、香豆酸、阿魏酸和苯甲酸的含量变化,分析MeJa与MeSa诱导植物叶片内酚酸含量的差异。结果表明:在不同的处理条件下,不同酚酸含量存在显著差异。MeJA及MeSa熏蒸后的黑杨叶片内没什子酸、香豆酸、咖啡酸、阿魏酸和苯甲酸含量均增加,且没什子酸含量在MeJa处理24h后达到最大量,在MeSa处理12天后达到最大量。MeJa及MeSa熏蒸后的合作杨叶片内没什子酸、邻苯二酚和阿魏酸含量也增加,儿茶酸和苯甲酸含量略有下降,咖啡酸和香豆酸在对照叶片和熏蒸叶片内都没有检测到。说明MeJa与MeSa可作为气体信号诱导植株产生防御反应。图4参23。 相似文献
4.
The wood-based moldings were fabricated by using only citric acid as an adhesive. The mechanical properties, water resistances,
thermal properties and chemical structure were investigated. Wood powder obtained from Acacia mangium was mixed with citric acid under certain weight ratios (0–40 wt%), and each powder mixture was molded using two types of
metal molds at 200°C and 4 MPa for 10 min. The modulus of rupture and the modulus of elasticity values of the wood-based molding
containing 20 wt% citric acid were 35.8 MPa and 5.4 GPa, respectively. The maximum impact strength was 0.94 kJ/m2 with the same citric acid content. The water resistance increased with increasing citric acid content, and the good resistance
to boiling water was also recognized. However, some elution of substances derived from citric acid was observed at high levels
of citric acid, causing a decrease in the thermal properties. The ester linkages were detected by Fourier transform infrared
spectroscopy, indicating that the citric acid reacted with the wood. Our results demonstrated that citric acid brought about
good adhesiveness for fabricating the wood-based molding. 相似文献
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From roots of Taraxacum udum, two new and four known sesquiterpene lactones were isolated, together with five known phenolic compounds. The new compounds were characterized as 11β, 13-dihydrotaraxinic acid and taraxinic acid 6-O-acetyl-β-glucopyranosyl ester by spectroscopic methods, especially 1D and 2D NMR, and by comparison with structurally related compounds. The plant material was shown to be a good source of taraxinic acid derivatives. 相似文献
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Yosuke Nakamura Hisashi Miyafuji Haruo Kawamoto Shiro Saka 《Journal of Wood Science》2011,57(4):331-337
Acetic acid fermentability of various compounds from beech wood as produced in a two-step hot-compressed water treatment was
evaluated by fermentation tests using standard compounds with Clostridium thermoaceticum and Clostridium thermocellum. For cellulose- and hemicellulose-derived products, the former microorganism was found to ferment compounds with low molecular
weights such as monosaccharides, decomposed products, and organic acids to acetic acid, while the latter was found to ferment
compounds with high molecular weights such as polysaccharides and oligosaccharides to acetic acid. Lignin-derived products
were, on the other hand, fermented by both microorganisms to acetic acid. Based on these lines of evidence, co-culture with
C. thermoaceticum and C. thermocellum was evaluated and proven to increase acetic acid fermentability. Consequently, almost all compounds produced from beech wood
in hot-compressed water were found to be converted to acetic acid when using these microorganisms in combination. Thus, hot-compressed
water treatment coupled with acetic acid fermentation would likely be a powerful method to produce acetic acid from lignocellulosics. 相似文献
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[目的]本文对芍药种子含油率、脂肪酸成分及含量进行了探讨,为芍药开发成油料植物提供参考。[方法]选取芍药36个栽培品种和1个野生居群为样本,采用索氏提取法提取种子油脂并测定含油率,用气相色谱—质谱联用仪(GC-MS)对提取的籽油成分进行分析。[结果]表明:芍药36个栽培品种和1个野生居群种子平均含油率为20.20%。芍药籽油主要含有豆蔻酸、棕榈酸、棕榈一烯酸、硬脂酸、油酸、亚油酸、亚麻酸和花生酸8种脂肪酸,其中,亚麻酸含量最高,平均达34.14%,其次为油酸和亚油酸,这3种不饱和脂肪酸的含量占全部脂肪酸的93.37%。芍药籽油脂肪酸含量变化相对稳定,各脂肪酸成分的变异系数从大到小依次为亚油酸(13.90%)油酸(13.51%)亚麻酸(10.71%)棕榈酸(0.18%)硬脂酸(0.09%)花生酸(0.002%)、棕榈一烯酸(0.002%)豆蔻酸(0.00%)。[结论]芍药种子含油率高,富含亚麻酸、亚油酸和油酸,且含量相对稳定,变异很小,具有开发为高含量亚麻酸食用油潜力。 相似文献
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A. Gugliucci Deborah H. Markowicz Bastos John Schulze Marina F. Ferreira Souza 《Fitoterapia》2009,80(6):339-344
The present study concentrates on the evaluation of the anti-glycation effect of some bioactive substances present in yerba maté (Ilex paraguariensis): 5-caffeoylquinic acid, caffeic acid and a sapogenin (oleanolic acid). Bovine serum albumin and histones were incubated in the presence of methylglyoxal with or without the addition of 5-caffeoylquinic acid, caffeic acid and oleanolic acid. After the incubation period, advanced glycation end product (AGE) fluorescence spectra were performed and protein structural changes were evaluated by Sodium Dodecyl Sulfate Polyacrylamide Gel Electrophoresis. Chlorogenic acid, caffeic acid are the main substances responsible for the anti-glycation effect of maté tea. 相似文献
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以松香酸、亚油酸、油酸、β-谷甾醇、甾醇油酸酯分别作为纸浆中单一树脂的模拟物,采用一种产自黄孢原毛平革菌的漆酶对树脂模拟物进行降解,通过对比漆酶/介体体系的降解效率,筛选了该漆酶合适的介体,探讨了漆酶/介体体系对单一树脂模拟物的降解效果,研究了漆酶/介体体系降解亚油酸和油酸的动力学,并对漆酶降解亚油酸的工艺条件进行了优化。研究结果表明:1-羟基苯并三唑(HBT)是较为合适的介体;漆酶/HBT体系对松香酸、亚油酸、油酸、β-谷甾醇、甾醇油酸酯单一树脂模拟物均有较好的降解效果;漆酶/HBT体系处理亚油酸、油酸的米氏常数分别为1.38和1.86mmol/L,表明亚油酸更易与漆酶/HBT体系结合;该漆酶处理亚油酸的最佳工艺条件为酶用量2.0U/mg、1-羟基苯并三唑介体用量7.6mol/g、时间60min、温度50℃、pH值4.0,此条件下亚油酸的降解率为88.9%,当酶用量增加到4.0U/mg或者处理时间延长至120min时,亚油酸的降解率可达到100%。 相似文献
10.
采用Olsen法测定土壤速效磷,采用土壤无机磷分级测定法测定土壤无机磷,分别测得在不同浓度草酸作用下哈尔滨市保护地土壤的磷含量的动态变化。试验结果表明,草酸对保护地土壤不同形态无机磷含量的影响分别是:草酸处理的Ca2-P含量、Ca8-P含量和Al-P含量随着草酸浓度的增加而增加;草酸处理的Fe-P含量和O-P含量随着培养时间的增加而增加;草酸处理的Ca10-P含量在24 h和96 h有2次的峰值,高浓度草酸处理的Fe-P、O-P、Ca10-P含量反而比低浓度处理的Fe-P、O-P、Ca10-P含量低。 相似文献
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Salviae miltiorrhizae is one of the most commonly used herbal plants in the treatment of numerous ailments including cardiovascular diseases for hundreds of years. According to the theory of traditional Chinese herbal medicine, S. miltiorrhizae is always used in combination with borneol to obtain better pharmacological effects. The purpose of this study was to investigate the effects of borneol on the pharmacokinetic and bioavailability of S. miltiorrhizae. The pharmacokinetics studying on rosmarinic acid, salvianolic acid A and salvianolic acid B which are the main active compounds of S. miltiorrhizae in rat plasma, was achieved using a optimal high-performance liquid chromatographic technique coupled with liquid-liquid extraction method. After administration of either single salvianolic acids or salvianolic acids in combination with borneol, plasma concentrations of rosmarinic acid, salvianolic acid A and salvianolic acid B of male Sprague-Dawley rats were determined at different time points (5, 10, 20, 30, 45, 60, 90, 120, 180, 240, 300, and 360 min). In comparison with salvianolic acid extract alone, there were statistically significant differences in pharmacokinetic parameters of rosmarinic acid, salvianolic acid B and salvianolic acid A, and the bioavailability of the three salvianolic acids increased by different degrees when the salvianolic acid extract and borneol were administered together. These results indicated that borneol could enhance the intestinal absorption, decrease the distribution and inhibit the metabolism of salvianolic acids. 相似文献
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[目的]确定引起天女木兰褐化现象的酚酸种类,筛选出最佳抗褐化剂及使用最适浓度。[方法]在B5培养基中分别添加各种抗褐化剂,芽外植体培养30 d后计算出褐化率,对褐化率结果进行统计分析,并比较三种抗褐化剂的抗褐化效果;另外,在组培过程中定期取样,利用HPLC测定芽外植体中咖啡酸、绿原酸和对香豆酸含量变化。[结果]表明:天女木兰芽外植体褐化过程中咖啡酸和绿原酸含量下降幅度较大,而对香豆酸含量下降幅度较小,说明咖啡酸和绿原酸容易被氧化,而对香豆酸较为稳定;三种抗褐化剂控制褐化现象发生的最佳效果排序为VCPVPCA;尽管PVP控制酚酸氧化效果不如CA,但是预防褐化效果确强于CA,其原因是由于二者抗褐化机理不同所致;VC使用的最适浓度为500 mg·L~(-1),如果超过此浓度会导致外植体褐化率增加;PVP最适浓度为1 000~1 500 mg·L~(-1),CA最适浓度为300 mg·L~(-1)。[结论]天女木兰芽外植体褐化底物是咖啡酸和绿原酸,而与对香豆酸无关;VC、PVP和CA三种抗褐化剂抗褐化机理各不相同,综合比较VC抗褐化效果最好,其次是PVP,CA排在最后。 相似文献
13.
采用GC-MS和DSC对索氏法、浸提法、超声波协同微波法和水酶法等4种方法提取的丝光绿蝇幼虫油脂的脂肪酸组成及热力学性质进行分析,为其开发和利用奠定基础。结果表明,浸提法油脂中共有15种脂肪酸,其余3中方法油脂均含有17种脂肪酸,主要成份为油酸、亚油酸、棕榈油酸和棕榈酸4种,占脂肪酸总量的89%左右,棕榈酸、棕榈油酸和油酸含量分别为248.47 mg·g-1、243.51 mg·g-1、174.96 mg·g-1,不饱和脂肪酸比例较高,约占脂肪酸含量的65%,其他必需脂肪酸花生四烯酸和DHA也有少量存在。不同方法提取的油脂的热动力学特性差异明显,油脂的熔点及玻璃化转变温度有一定差异。浸提法提取油脂的性质较差,超声波协同微波法是最适合丝光绿蝇幼虫油脂提取的方法,得到的油脂品质较好,具有开发和利用价值。 相似文献
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The chemical conversion of red pine sulfuric acid lignin (Klason lignin) (SAL) as an acid hydrolysis lignin sample to water-soluble arylsulfonates of lignin derivation (i.e., phenolized SAL) was investigated. Treatment of phenolized SAL with chlorosulfonic acid followed by alkali hydrolysis gave water-soluble sulfonated products with a sulfonic acid group on their aromatic nuclei quantitatively. The products possess 2.0 SO3Na/C9 C6. In contrast, the content of sulfuric acid group in sulfonated SAL was only 0.33C9. Chlorosulfonation of 1-guaiacyl-l-p-hydroxyphenylethane as a phenolized guaiacyl lignin model compound revealed that the sulfonyl chloride group was introduced at thepara position of an aromatic methoxyl group, theortho position of a phenolic hydroxyl group, or both. 相似文献
15.
The formation of a complex with aluminum by low molecular weight compounds and saponified ozone-treated kraft lignins was
evaluated based on the decrease in pH of their solutions on the addition of 0.1 M AlCl3. Decreases in pH were observed with the solutions containing compounds having adjacent carboxyl groups (oxalic acid), carboxyl/alcoholic
hydroxyl groups (glycolic acid), carboxyl/formyl groups (glyoxylic acid), and phenolic hydroxyl groups (protocatechuic acid)
on the addition of 0.1 M AlCl3. The malonic and phthalic acids, having two carboxyl groups, were also effective. These results show that the compounds were
effective in forming complexes with aluminum. This finding corresponds to the fact that aluminum toxicity is reduced by formation
of a complex with aluminum, except in phthalic acid. The chemical structures stated above in ozone-treated kraft lignins contribute,
at least partly, to the complex with aluminum. The pH of solutions containing saponified ozone-treated kraft lignins and alkaline-treated
kraft lignin decreased more than that without modified kraft lignins on the addition of 0.1 M AlCl3, showing that they were effective in forming a complex with aluminum. The high molecular weight part of saponified ozone-treated
kraft lignin was effective in forming a complex with aluminum and in reducing its toxicity. 相似文献
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Seeds of Albizia chinensis(Osb.) Merr. in addition to water were also treated with different treatments by incubating in ethyl alcohol, acetone, and petroleum ether at room temperature for different du... 相似文献
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H. Yamaguchi 《Wood Science and Technology》2002,36(5):399-417
A new wood preservative containing low molecular weight and low-toxicity silicic acid (LWSA) was investigated. To prevent
environmental pollution with the wood preservative, a silicic acid monomer aqueous solution (SAMS) or colloidal silicic acid
solution (CSAS) was combined with various metal compounds or boric acid. Agents where SAMS or CSAS was combined with boric
acid gave good protection against decay caused by the brown-rot fungus Fomitopsis palustris, the treated wood (Cryptomera japonica D. Don) specimens after the leaching test maintained a high resistance to decay. The leaching and decay tests revealed high
quantities of chemicals leaching from wood treated with SAMS-metal agents. However, when wood was treated with SAMS-boric
acid, there was little leaching of agent in either test. The mechanism of resistance of wood, which was treated with boric
acid mixed with CSAS or SAMS, to the brown-rot fungus F. palustris were investigated. When the concentration of boric acid was high, mycelial growth was inhibited completely and no protein
production was detected. When the amount of boric acid was low, the xylanase, mannase and cellulase activities were lower
than with control wood powder. When powdery boric acid was combined with CSAS, it was considered that the treated woods have
higher anti-weather properties than when boric acid-methanol solution was mixed with CSAS. The agent-preparation method adopted
should be considered carefully after taking the treatment process and the intended use of the preservative-treated wood into
account.
Received 26 September 2000
This study was supported by a Grant-in-Aid (09460079) for Scientific Research from the Ministry of Education, Science, and
Culture of Japan. 相似文献
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The mechanism of paper sizing in fatty acid soap size-alum systems was studied by structural analyses of the size components in handsheets prepared with13C-labeled fatty acid soap size. Patterns of sizing performance and aluminum content of the handsheets were similar to those for the rosin soap size-alum sizing systems, although the patterns of calcium content were different. Solid-state13C-nuclear magnetic resonance analysis of the handsheets revealed that fatty acid calcium salt was the predominant size component in the handsheets prepared using tap water. This calcium salt is formed from the fatty acid soap size (fatty acid potassium salt) by ion exchange with calcium ion in pulp suspensions and retained on pulp fibers through aluminum compounds originating from alum added. On the other hand, when deionized water was used, free fatty acid was the major component in the handsheets. Fatty acid aluminum salt was present as a minor component in the handsheets prepared in both tap water and deionized water systems. Therefore, all size components (i.e., fatty acid calcium salt, free fatty acid, fatty acid aluminum salt) seem to contribute to the appearance of sizing features.This research was presented in part at the 64th Pulp and Paper Research Conference of Japan TAPPI, Tokyo, June 1997 相似文献
19.
B. Popovic 《Forest Ecology and Management》1984,8(2):81-93
Short-term incubation experiments were carried out with humus samples from acidification experiments in the field, and the effect on the nitrogen mineralization was studied. A tendency for a positive effect of acid treatment on the mineral nitrogen accumulation was most evident in samples from Åseda, South Sweden. The field experiments also included NPK-fertilization, alone or combined with acid treatments. The strong positive effect of NPK-fertilizers on the nitrogen mineralization was depressed by the sulphuric acid supply. Nitrification was strongly reduced by acid addition, but markedly increased by liming in combination with NPK-fertilization. Soil respiration decreased markedly in samples from acidified plots. 相似文献
20.
This study evaluated oxalic acid accumulation and bioremediation of chromated copper arsenate (CCA)-treated wood by three brown-rot fungi Fomitopsis palustris, Coniophora puteana, and Laetiporus sulphureus. The fungi were first cultivated in a fermentation broth to accumulate oxalic acid. Bioremediation of CCA-treated wood was then carried out by leaching of heavy metals with oxalic acid over a 10-day fermentation period. Higher amounts of oxalic acid were produced by F. palustris and L. sulphureus compared with C. puteana. After 10-day fermentation, oxalic acid accumulation reached 4.2 g/l and 3.2 g/l for these fungi, respectively. Fomitopsis palustris and L. sulphureus exposed to CCA-treated sawdust for 10 days showed a decrease in arsenic of 100% and 85%, respectively; however, C. puteana remediation removed only 18% arsenic from CCA-treated sawdust. Likewise, chromium removal in F. palustris and L. sulphureus remediation processes was higher than those for C. puteana. This was attributed to low oxalic acid accumulation. These results suggest that F. palustris and L. sulphureus remediation processes can remove inorganic metal compounds via oxalic acid production by increasing the acidity of the substrate and increasing the solubility of the metals.An erratum to this article can be found at 相似文献