高等学校化学学报 ›› 2022, Vol. 43 ›› Issue (6): 20210835.doi: 10.7503/cjcu20210835

• 高分子化学 • 上一篇    下一篇

NaBH4/MCl x 体系对液体端羧基氟橡胶的还原及还原机理

常云飞, 廖明义(), 温佳明   

  1. 大连海事大学交通运输工程学院, 大连 116026
  • 收稿日期:2021-12-16 出版日期:2022-06-10 发布日期:2022-02-22
  • 通讯作者: 廖明义 E-mail:liaomy@dlmu.edu.cn
  • 基金资助:
    国家自然科学基金(51873026)

Reduction Performance and Mechanism of Liquid Terminated-carboxyl Fluoroelastomers Using NaBH4/MCl x Reduction System

CHANG Yunfei, LIAO Mingyi(), WEN Jiaming   

  1. College of Transportation Engineering,Dalian Maritime University,Dalian 116026,China
  • Received:2021-12-16 Online:2022-06-10 Published:2022-02-22
  • Contact: LIAO Mingyi E-mail:liaomy@dlmu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(51873026)

摘要:

以液体端羧基氟橡胶(LTCFs)为原料, 硼氢化钠与金属氯化物(NaBH4/MCl x )为还原体系, 采用一锅法成功将LTCFs还原为液体端羟基氟橡胶(LTHFs). 研究了多种稀土金属氯化物(LaCl3, CeCl3, NdCl3和SmCl3)和过渡金属氯化物(MnCl2, NiCl2, CoCl2和CuCl2)对LTCFs还原效果的影响及变化规律. 采用傅里叶变换红外光谱(FTIR)、 核磁共振氢谱(1H NMR)、 核磁共振氟谱(19F NMR)和化学滴定法对原料和产物的分子链结构和官能团含量进行了表征. 结果表明, 稀土金属MCl x 还原体系对LTCFs的还原效果均高于过渡金属MCl x 还原体系, LTCFs中的—C=C—和—COOH均可以被还原为—C—C—和—OH, 其中NaBH4/SmCl3还原体系还原效率最高, 达到92%. 机理研究表明, NaBH4/MCl x 对—COOH的还原性能与MCl x 中金属阳离子和羰基氧间的结合力有关, 结合力越大越有利于—COOH的还原.

关键词: 液体端羧基氟橡胶, 金属氯化物, 硼氢化钠(NaBH4), 羧基, 还原机理

Abstract:

Using a simple one-pot method, direct transformation of liquid terminated-carboxyl fluoroelastomers(LTCFs) to the corresponding liquid terminated-hydroxyl fluoroelastomers(LTHFs) was easily realized with sodium borohydride(NaBH4) in the presence of metal chloride(MCl x ). The structure and functional group content of LTCFs and LTHFs were analyzed by Fourier transform infrared spectroscopy(FTIR), 1H nuclear magnetic resonance(1H NMR) spectrocopy, 19F nuclear magnetic resonance(19F NMR) spectrocopy and chemical titration. The results showed that —C=C— and carboxyl groups of LTCFs were reduced efficiently. The effect of different rare-earth chlorides(LaCl3, CeCl3, NdCl3 and SmCl3) and transition metal chlorides(MnCl2, NiCl2, CoCl2 and CuCl2) on the performances of the LTCFs reduction was discussed. The NaBH4/SmCl3 system was the best and the reduction rate reached 92% under optimum reaction conditions. Mechanism research showed that the stronger binding force of metal ion and carbonyl oxygen was beneficial to the reduction of LTCFs.

Key words: Liquid terminated-carboxyl fluoroelastomer, Metal chloride, NaBH4, Carboxyl, Reduction mechanism

中图分类号: 

TrendMD: