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      化學工業(yè)

      2015-11-01 01:34:24
      中國學術期刊文摘 2015年16期
      關鍵詞:離子鍵熱穩(wěn)定性氫鍵

      化學工業(yè)

      封面介紹:膠原生物大分子因具有特殊的生物活性而在許多領域備受青睞.利用離子液體(IL)中陽離子可作為電子接受體而陰離子作為強氫鍵受體的特性來高效溶解制備膠原溶液具有廣闊的應用前景.封面圖給出了皮膠原在兩種IL中的溶解機理.由圖可見,IL中的陰陽離子對解離為自由的[BMIM]+和Cl-(Ac-)后分別與膠原肽鍵中的羰基氧或者—NH—上的H結合.同時由于靜電力的作用,它們可分別與膠原側鏈離子化的COO-與NH3+相互吸引鍵合.IL與膠原分子間新形成的氫鍵與離子鍵,打斷了膠原分子間原有的氫鍵及離子鍵,最終導致膠原鏈能夠自由地運動并溶解于其中.詳見本期2196-2204頁.

      膠原在兩種離子液體[BMIM]Cl和[BMIM]Ac中的溶解及再生結構比較

      劉潔,趙世玉,徐洲,等

      采用離子交換法,以1-丁基-3-甲基氯代咪唑([BMIM]Cl)為原料合成了咪唑醋酸鹽型離子液體([BMIM]Ac),以兩者為溶劑研究了膠原纖維在咪唑類離子液體中的溶解行為及再生前后的結構與熱穩(wěn)定性變化.結果表明,膠原纖維在CH3COO-和Cl-型離子液體中均能溶解,但具有明顯不同的溶解特性.相對[BMIM]Cl的溶解性能而言,[BMIM]Ac能夠在較低的溫度下獲得高濃度和良好流動性的膠原溶液,而且再生膠原的三股螺旋結構保留度更高.FTIR、UV、XRD、CD、TG分析結果表明,膠原在咪唑離子液體中溶解前后其化學結構未發(fā)生明顯變化,而三股螺旋的保留度和熱穩(wěn)定性略有降低.

      離子液體;膠原;溶解;再生;結構與性能變化

      來源出版物:化工學報,2015,66(6): 2196-2204聯系郵箱:范浩軍,fanhaojun@scu.edu.cn

      來源出版物:Chinese Journal of Chemical Engineering,2015,23(6): 954-961聯系郵箱:WANG Jin-fu,wangjfu@tsinghua.edu.cn

      封面介紹:A detailed kinetic model of the synthesis of methylphenyldichlorosilane(MPDS)from methyldichlorosilane and chlorobenzene by gas phase condensation was developed. The calculated results were in a good agreement with the experimental results. The main pathway of MPDS production was proposed and proved. The kinetic model can be used in design and optimization of the industrial reactor for MPDS synthesis(See Liu et al. Pages 954-961).

      Detailed kinetics of methylphenyldichlorosilane synthesis from methyldichlorosilane and chlorobenzene by gas phase condensation

      LIU Tong ,WANG Tie-feng,HUANG Yun-long,et al.

      Methylphenyldichlorosilane(MPDS,CH3C6H5SiCl2)is an important silicone monomer for the synthesis of highperformance polymethylphenylsiloxane polymers. In this work,the mechanism of the synthesis of MPDS from methyldichlorosilane and chlorobenzene by gas phase condensation was studied,and a kinetic model with 35 species and 58 elementary reactions was established. Experiments were carried out in a tubular reactor under a wide range of reaction conditions. The calculated mole fractions of the reactants and products were in a good agreement with the experimental results. A mechanism of the insertion of chloromethylsilylene into the CCl bond of chlorobenzene was proposed,which was proved to be the main pathway of MPDS production. The established kinetic model can be used in design and optimization of the industrial reactor for MPDS synthesis.

      Detailed kinetics; Methylphenyldichlorosilane; Chloromethylsilylene; Gas phase condensation

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