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The physical and chemical changes occurring during heating cellulose, thermal reaction of pentachlorophenol and its derivatives, and accessibility studies of cellulosic materials.

机译:在加热纤维素,五氯苯酚及其衍生物的热反应以及纤维素材料的可及性研究过程中发生的物理和化学变化。

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摘要

The overall objectives of this study were to determine the effects of heating on cellulose and on pentachlorophenol. Both of these materials are very important to the Forest Products Industries.; Cellulose is the major constituent of all plants including wood and cotton. The chemical and physical properties of cellulose can be modified by using the low temperature thermal pretreatment method.; Pentachlorophenol is used in wood to protect wood from biological degradation. Under high temperatures and alkaline conditions, pentachlorophenol can be converted into highly toxic compounds such as dioxins and furans.; In this study, the thermal reactions of pentachlorophenol and its derivatives were characterized by TGA, FT-IR, and HPLC. The chemical properties of thermal treated cotton cellulose were investigated by determination of total available glucose (TAG), FT-IR spectroscopy, and enzymatic hydrolysis. The microporous properties of treated and untreated cotton cellulose and the accessibility of cellulosic materials were evaluated by the solute exclusion method.; The major thermal reaction of salts of pentachlorophenol at 350{dollar}spcirc{dollar}-500{dollar}spcirc{dollar}C involves the ortho positions of two pentachlorophenate molecules which undergo a condensation reaction, leading to octachlorodibenzo-p-dioxin (OCDD) formation. The maximum OCDD recovery from pentachlorophenate salts was found to be 88% at 500{dollar}spcirc{dollar}C. For low temperature treated cotton cellulose, chemical analysis indicates only minor changes in the molecular structure and FT-IR spectra also show a slight increase in the carbonyl group. However, the major thermal effects on the cotton cellulose between 160{dollar}spcirc{dollar}-200{dollar}spcirc{dollar}C involve changes in surface area and in pore structure. This in turn affects enzymatic hydrolysis rates, water properties, and dimensional stability. In the accessibility study, the accessibility of cellulosic materials is shown to vary according to the degree of pretreatment of the cellulosic materials.
机译:这项研究的总体目标是确定加热对纤维素和五氯苯酚的影响。这两种材料对林产品工业都非常重要。纤维素是包括木材和棉花在内的所有植物的主要成分。纤维素的化学和物理性质可以通过使用低温热预处理方法来改变。五氯苯酚用于木材中以保护木材免受生物降解。在高温和碱性条件下,五氯苯酚可转化为剧毒化合物,例如二恶英和呋喃。在本研究中,通过TGA,FT-IR和HPLC对五氯苯酚及其衍生物的热反应进行了表征。通过测定总有效葡萄糖(TAG),FT-IR光谱和酶水解研究了热处理棉纤维素的化学性质。用溶质排除法评价处理过的和未处理过的棉纤维素的微孔性能以及纤维素材料的可及性。五氯苯酚盐在350 {spcirc {dollar} -500 {dollar} spcirc {dollar} C处的主要热反应涉及两个五氯酚酸酯分子的邻位,后者发生缩合反应,从而导致八氯二苯并对二恶英(OCDD) )形成。发现在500℃时,从五氯酚盐的最大OCDD回收率为88%。对于低温处理的棉纤维素,化学分析表明分子结构仅发生了微小变化,FT-IR光谱也显示出羰基的轻微增加。然而,在160℃至200℃之间对棉纤维素的主要热效应涉及表面积和孔结构的变化。反过来,这会影响酶促水解速率,水性质和尺寸稳定性。在可及性研究中,纤维素材料的可及性显示根据纤维素材料的预处理程度而变化。

著录项

  • 作者

    Shiau, Ing Luen.;

  • 作者单位

    Mississippi State University.;

  • 授予单位 Mississippi State University.;
  • 学科 Agriculture Wood Technology.
  • 学位 Ph.D.
  • 年度 1988
  • 页码 134 p.
  • 总页数 134
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 森林采运与利用;
  • 关键词

  • 入库时间 2022-08-17 11:50:43

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