私密直播全婐app免费大渔直播,国产av成人无码免费视频,男女同房做爰全过程高潮,国产精品自产拍在线观看

相關(guān)鏈接
聯(lián)系方式
  • 通信地址:杭州市 浙江大學(xué)玉泉校區(qū)高分子大樓421房間
  • 郵編:310027
  • 電話:0571-87953732
  • 傳真:0571-87953732
  • Email:xhzhang@zju.edu.cn
當(dāng)前位置:> 首頁 > 論文著作 > 正文
Highly Active Organic Lewis Pairs for the Copolymerization of Epoxides with Cyclic Anhydrides: Metal-Free Access to Well-Defined Aliphatic Polyesters
作者:Lan-Fang Hu, Cheng-Jian Zhang, Hai-Lin Wu, Jia-Liang Yang, Bin Liu, Han-Yi Duan, and Xing-Hong Zh
關(guān)鍵字:Epoxides with Cyclic Anhydrides,Metal-Free,
論文來源:期刊
具體來源:Macromolecules 2018, 51, 3126?3134
發(fā)表時(shí)間:2018年

Polyester synthesis from the alternating copolymerization of epoxides with cyclic anhydrides via a metal-free route remains a key challenge. This work reports the development of a highly active organocatalytic route for the copolymerization of a spectrum of epoxides and cyclic anhydrides. Fully alternating polyesters were synthesized by a variety of organic Lewis acid?base pairs including organoboranes and quaternary onium salts. The effect of the acidity, type, and size of Lewis pairs on the catalytic activity and selectivity of the copolymerization is

presented. The undesirable transesterification and etherification were effectively suppressed even in the case of complete conversion of the cyclic anhydride. This could be ascribed to the formation of a unique tetracoordinate bond-carboxylate (or alkoxide) anion. The Lewis pairs

are highly active, with a turnover frequency of 102 and 303 h?1 for the copolymerization of propylene oxide with maleic anhydride and phthalic anhydride, respectively, at 80 °C. Block polyester with narrow polydispersity of 1.05 was achieved via a sequential addition strategy. This work provides robust organocatalysts for the selective copolymerization of epoxides with cyclic anhydrides.


主站蜘蛛池模板: 琼结县| 沧州市| 嘉鱼县| 福安市| 南城县| 台中县| 泸水县| 黎平县| 比如县| 萨迦县| 高台县| 拉萨市| 南雄市| 海丰县| 醴陵市| 温泉县| 堆龙德庆县| 新郑市| 南阳市| 内黄县| 巨鹿县| 体育| 叶城县| 仲巴县| 崇仁县| 高阳县| 庄浪县| 福鼎市| 清原| 什邡市| 上蔡县| 教育| 察隅县| 南靖县| 湛江市| 新绛县| 南郑县| 凌海市| 彝良县| 成武县| 贡嘎县|