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頁籤選單縮合
題名 | The Alkaline Anthraquinone-Amylose Reactions: Yield Preservation and Random Chain Cleavage(Part 2)--Reaction Mechanism=直鏈澱粉與AQ之鹼性反應:產率提升和高分子斷鍵(2)--反應機制 |
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作者姓名(中文) | 張慎餘; | 書刊名 | 林產工業 |
卷期 | 15:3 1996.09[民85.09] |
頁次 | 頁491-506 |
分類號 | 476.1 |
關鍵詞 | 直鏈澱粉; 降解反應; 反應速率; 反應機構; 木材製漿; 溫度效應; Amylose; Anthraquinone; Alkaline degradation; Kinetics; Mechanism; Wood pulping; AQ; |
語文 | 英文(English) |
中文摘要 | AQ(9,10-二氫二酮-〔9,10〕)製漿法在過去近二十年間已廣被世界各地所接受。其主要原因是AQ可以加速製漿反應並且提高漿的產率。本研究中運用直鏈澱粉來模擬碳水化合物(譬如纖維素)在鹼性環境下的兩項重要反應,即產率的提升和高分子斷鍵。研究結果發現當AQ不存在於反應系統中時,直鏈澱粉會因為降解反應的發生而損失其質量。而此質量之損失會因為另一「停止反應」而顯著降低降解反應的重要性,進而保護住直鏈澱粉的質量。另外,當AQ不存在時,研究結果並沒有發現高分子斷鍵的現象。可是當AQ被添加到反應系統中時,在同樣條件下,不僅直鏈澱粉的質量增加了,高分子的鏈長也比沒有AQ時要短。因此,AQ會導致直鏈澱粉的產率提升,但是也會造成澱粉高分子的斷鍵。以上反應的反應速率常數,反應溫度的影響,以及其反應機構均於本篇實驗報告中做詳細討論。 |
英文摘要 | Amylose was used as model compound for cellulose. And two major reactions, namely, yield loss and random chain cleavage were examined for alkaline reactions of amylose both with and without anthraquinone (AQ). For amylose reactions without the presence of AQ, both peeling and stopping reactions are operative under the reaction conditions, with peeling occurring more easily than stopping. The initial ratio of the peeling rate coefficient to the stopping rate coefficient decreases as the temperature increases, indicative of an increased impoortance of the stopping reaction at higher temperatures. On the other hand, random chain cleavage does not occur significantly under the experimental conditions without the presence of AQ. When AQ is present in the amylose reactions, it is effective in preserving amylose yield. However, the effectiveness of AQ yield preservation decreases as temperature increases. At lower temperatures, the yield preservation is probably accomplished by aldonic acids formation. But at higher temperatures, mechanisms other than oxidation may account for the yield preservation by AQ in alkaline systems. AQ is able to induce random chain cleavage. However, it appears that AQ induces chain cleavage only at high temperatures. Induced chain cleavage implies that AQ can produce pulps with lower strength. Free radicals are probably involved in the mechanisms of AQ chain cleavage reaction. |
本系統之摘要資訊系依該期刊論文摘要之資訊為主。