化學(xué)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(lǐng)域備受青睞.利用離子液體(IL)中陽(yáng)離子可作為電子接受體而陰離子作為強(qiáng)氫鍵受體的特性來(lái)高效溶解制備膠原溶液具有廣闊的應(yīng)用前景.封面圖給出了皮膠原在兩種IL中的溶解機(jī)理.由圖可見(jiàn),IL中的陰陽(yáng)離子對(duì)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(jié)合.同時(shí)由于靜電力的作用,它們可分別與膠原側(cè)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(dǎo)致膠原鏈能夠自由地運(yùn)動(dòng)并溶解于其中.詳見(jiàn)本期2196-2204頁(yè).
膠原在兩種離子液體[BMIM]Cl和[BMIM]Ac中的溶解及再生結(jié)構(gòu)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?xún)烧邽槿軇┭芯苛四z原纖維在咪唑類(lèi)離子液體中的溶解行為及再生前后的結(jié)構(gòu)與熱穩(wěn)定性變化.結(jié)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(duì)[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(dòng)性的膠原溶液,而且再生膠原的三股螺旋結(jié)構(gòu)保留度更高.FTIR、UV、XRD、CD、TG分析結(jié)果表明,膠原在咪唑離子液體中溶解前后其化學(xué)結(jié)構(gòu)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(jié)構(gòu)與性能變化
來(lái)源出版物:化工學(xué)報(bào),2015,66(6): 2196-2204聯(lián)系郵箱:范浩軍,fanhaojun@scu.edu.cn
來(lái)源出版物:Chinese Journal of Chemical Engineering,2015,23(6): 954-961聯(lián)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