24小时热门版块排行榜    

查看: 1191  |  回复: 5

超级小笨瓜

银虫 (小有名气)

[求助] RAFT试剂对强酸的稳定性问题

有做RAFT试剂的大神没,RAFT试剂(二硫酯)对有机强酸如三氟乙酸的稳定如何,能否在RAFT聚合的过程中加入强酸同时实现可控/"活性"聚合。
回复此楼
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

shakete

金虫 (正式写手)

【答案】应助回帖

★ ★ ★ ★ ★
感谢参与,应助指数 +1
超级小笨瓜: 金币+3, 有帮助 2013-06-24 20:13:28
Meteorの泪: 金币+2, 感谢交流 2013-06-24 20:57:13
Chaleux好像一篇文章中提到过RAFT试剂在酸性条件下会水解
具体数值不太清楚,应该是70℃下几个小时内就有相当量的RAFT试剂水解
所以加入强酸之后可能会有一定的影响
2楼2013-06-24 18:16:53
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

超级小笨瓜

银虫 (小有名气)

引用回帖:
2楼: Originally posted by shakete at 2013-06-24 18:16:53
Chaleux好像一篇文章中提到过RAFT试剂在酸性条件下会水解
具体数值不太清楚,应该是70℃下几个小时内就有相当量的RAFT试剂水解
所以加入强酸之后可能会有一定的影响

能给下文章的题目么
3楼2013-06-24 20:13:49
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

love-study

至尊木虫 (职业作家)

【答案】应助回帖

★ ★ ★ ★
感谢参与,应助指数 +1
Meteorの泪: 金币+1, 感谢交流 2013-06-24 20:57:57
超级小笨瓜: 金币+3, ★★★很有帮助 2013-06-24 21:45:35
双硫脂在强酸体系里的稳定性不是很好,能发生酸解反应
学海无涯
4楼2013-06-24 20:25:30
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

shakete

金虫 (正式写手)

【答案】应助回帖

★ ★ ★ ★
超级小笨瓜: 金币+4, ★★★很有帮助 2013-06-25 15:50:41
Trithiocarbonates are known to be less subjected to hydrolysis than dithiobenzoate.(47, 48) However, a UV study performed at pH = 8.0 revealed that after only 30 min at 80 °C the absorbance of the PMAA macroRAFT agent at λ = 310 nm (corresponding to the maximum absorbance of the thiocarbonylthio function) decreased by 36% meaning that one-third of the chains had lost their RAFT chain end. After 5 h, only 14% of the chains still carried an active chain end. These results clearly explain the high amount of unreacted PMAA-CTPPA observed at this pH and the consequent poor control of the polymerization. By comparison, the hydrolytic stability of PMAA-CTPPA was significantly better at pH = 3.4 since a decay of only 4% was observed after 30 min at 80 °C and the proportion of living chains was still of 75% after 5 h (see Figure S2 in Supporting Information). In the emulsion polymerization performed at pH = 3.4, PMAA-CTPPA chains do not spend more than 45 min in the aqueous phase (Figure 1) and chain end hydrolysis can thus be neglected.


不知道怎么发图片,就把原句截下来了
http://pubs.acs.org/doi/full/10.1021/ma300875y这是文献的出处
atch Emulsion Polymerization Mediated by Poly(methacrylic acid) MacroRAFT Agents: One-Pot Synthesis of Self-Stabilized Particles
5楼2013-06-25 09:48:19
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖

lanye6209

铁杆木虫 (正式写手)

一般pH在2以上不会有太大的影响,当然时间不能太长
在路上走走看看
6楼2013-06-26 10:35:38
已阅   回复此楼   关注TA 给TA发消息 送TA红花 TA的回帖
相关版块跳转 我要订阅楼主 超级小笨瓜 的主题更新
最具人气热帖推荐 [查看全部] 作者 回/看 最后发表
[公派出国] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +3 5lbyq5wrhb 2026-02-07 3/150 2026-02-08 03:05 by vs90ilomwc
[考博] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +3 5lbyq5wrhb 2026-02-07 3/150 2026-02-08 02:52 by vs90ilomwc
[论文投稿] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +3 3rkserf6qr 2026-02-07 4/200 2026-02-08 02:45 by vs90ilomwc
[硕博家园] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +3 3rkserf6qr 2026-02-07 3/150 2026-02-08 02:32 by vs90ilomwc
[考博] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +5 2h7du0nuhk 2026-02-07 5/250 2026-02-08 02:25 by vs90ilomwc
[硕博家园] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +4 2h7du0nuhk 2026-02-07 5/250 2026-02-08 02:12 by vs90ilomwc
[考博] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +4 2h7du0nuhk 2026-02-07 6/300 2026-02-08 02:07 by vs90ilomwc
[教师之家] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +4 2h7du0nuhk 2026-02-07 6/300 2026-02-08 02:05 by vs90ilomwc
[找工作] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +4 2h7du0nuhk 2026-02-07 6/300 2026-02-08 01:46 by vs90ilomwc
[公派出国] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +4 2h7du0nuhk 2026-02-07 7/350 2026-02-08 01:45 by vs90ilomwc
[考博] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +4 2h7du0nuhk 2026-02-07 7/350 2026-02-08 01:32 by vs90ilomwc
[硕博家园] 售SCI一区文章,我:8 O5 51O 54,科目齐全 +4 2h7du0nuhk 2026-02-07 7/350 2026-02-08 01:12 by vs90ilomwc
[教师之家] 有院领导为了换新车,用横向课题经费买了俩车 +7 瞬息宇宙 2026-02-04 7/350 2026-02-07 21:47 by tfang
[有机交流] 酰胺脱乙酰基 10+5 chibby 2026-02-03 12/600 2026-02-07 19:29 by 江东闲人
[基金申请] 同年申请2项不同项目,第1个项目里不写第2个项目的信息,可以吗 +4 hitsdu 2026-02-06 4/200 2026-02-07 13:07 by jurkat.1640
[基金申请] 有时候真觉得大城市人没有县城人甚至个体户幸福 +9 苏东坡二世 2026-02-04 10/500 2026-02-07 12:37 by 小毛球
[考博] 天津大学招2026.09的博士生,欢迎大家推荐交流(博导是本人) +4 a793625982 2026-02-05 5/250 2026-02-07 10:57 by a793625982
[公派出国] CSC & MSCA 博洛尼亚大学能源材料课题组博士/博士后招生|MSCA经费充足、排名优 +4 雨念 2026-02-01 6/300 2026-02-06 23:32 by MelissaPon
[硕博家园] 博士延得我,科研能力直往上蹿 +7 偏振片 2026-02-02 7/350 2026-02-04 17:36 by 陈氏帝国
[教师之家] 遇见不省心的家人很难过 +18 otani 2026-02-03 22/1100 2026-02-04 11:06 by tangmnt
信息提示
请填处理意见