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Study on Vinyl Polymerization Initiation Mechanism | Môn Công nghệ hóa học - Đại học Sư phạm Kỹ thuật Thành phố Hồ Chí Minh

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Study on Vinyl Polymerization Initiation Mechanism Môn Công nghệ hóa học. Tài liệu được sưu tầm gồm 7 trang, giúp bạn ôn tập tốt hơn. Mời các bạn đón xem. 

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Tác giả:

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Linh Giang

1 tuần trước
Danh sách Quiz
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82
X.
D. Feng,
X.
Q.
Guo,
K. Y.
320
400
5
A
Inm
Fig.
6
.
The
CTC
spectra
of
PMMA in TCNE/CH,Cl,
solution.
(1)
:
PMMA (initiation
by
AIBN),
(2):
PMMA (initiation
by
TMEDA/APS),
(3):
TMEDA/TCNE in CH,Cl,
Initiation mechanbm
Based
on
the results discussed above, the following initiation mechanism
of
the
TMEDA/persulfate system via contact charge transfer complex
(
CCT)
and cyclic
transition state
CTS)
(
may
be proposed.
so:-
CTS
5
+
H20
-
HSOa
-
1
+
'OSO,H
5
+
HO.
6
The free radicals
1
,
5
and
6
are responsible for the initiation
of
vinyl polymeriza-
tion.
In
the absence
of
monomers, the primary free radical
1
may undergo fi-scission
to form free radical
3
and the unstable imino compound
4
,
which will react with water
to form methylamine and formaldehyde6).
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Study of the initiation mechanism
of
the vinyl polymerizationw ith the system.
.
.
83
In the case
of
a high concentration
of
TMEDA, a free radicalc hain transfer reac-
tion may take place to form radical
2
by reaction
of
radicals
1
,5
or
6
with TMEDA.
The authors are indebted to the
National Natural ScienceF oundation
of
China
for
financial
support of this work.
’)
U.S.
4189370 (1980)
,
Assignee, Societe Sebia, inv.: E. Boschetti;
Chem. Abstr.
93
,
4104631
,
2
T. Tanaka,
Sci. Am.
244
(
l), 110 (1981)
,
3
M. K.
Gupta,
R.
Bansil,
Polym. Prepr. (Am. Chem.
Soc.,
Div.
Polym. Chem.)
22
(2)
.
375
4
,
X.
Q. Guo,
K.
Y.
Qiu,
X.
D.
Feng,
Scientia Sinica,
B
30
(9)
, 897 (1987)
@
J.
March,
“Advanced Organic Chemistry Reactions, Mechanism andS tructure”,
2
nd Ed.,
(
1
980)
(1981)
E. Collinson,
F.
S.
Dainton,
G.
S.
McNaughton,
Trans. Faruday
SOC.
53
,
489 (1957)
McGraw-Hill, New
York
1977
,
p.
806
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X. D. Feng, X. Q. Guo, K. Y. Qiu
Fig. 6 . The CTC spectra of PMMA in TCNE/CH,Cl,
solution. (1) PMMA (initiation
by AIBN :) , (2): PMMA (initiation
by TMEDA/APS), (3): TMEDA/TCNE in CH,Cl, 320
400 5 A Inm
Initiation mechanbm
Based on the results discussed above, the following initiation mechanism of the
TMEDA/persulfate system via contact charge transfer complex ( CCT) and cyclic transition state (C TS) may be proposed. - so:-
1 + 'OSO,H 5 CTS
5 + H20 - HSOa + HO. 6
The free radicals 1 , 5 and 6 are responsible for the initiation of vinyl polymeriza-
tion. In the absence of monomers, the primary free radical 1 may undergo fi-scission
to form free radical 3 and the unstable imino compound 4 , which will react with water
to form methylamine and formaldehyde6).
Downloaded by Lynh Nguyen (lynhn228@gmail.com) lOMoAR cPSD| 58675420
Study of the initiation mechanism o
f the vinyl polymerizationw ith the system. . . 83 In the case
of a high concentration o
f TMEDA, a free radicalc hain transfer reac-
tion may take place to form radica 2 l by reaction of radicals
1,5 or 6 with TMEDA.
The authors are indebted to the
National Natural ScienceF oundation
of China for financial support of this work.
’) U.S. 4189370 (1980) , Assignee, Societe Sebia, inv.: E. Boschetti;
Chem. Abstr. 93 , 4104631 ( 980 ) , 2 T
1. Tanaka, Sci. Am. 244 ( l), 110 (1981) ,
3 M. K. Gupta, R. Bansil, Polym. Prepr. (Am. Chem. Soc., Div. Polym. Chem.) 22 (2) . 375 (1981)
4 , X. Q. Guo, K. Y. Qiu, X. D. Feng, Scientia Sinica, B 30 ( 9) , 897 (1987)
E. Collinson, F. S. Dainton, G. S. McNaughton, Trans. Faruday SOC. 53 , 489 (1957)
@ J. March, “Advanced Organic Chemistry Reactions, Mechanism andS tructure”, 2 nd Ed.,
McGraw-Hill, New York 1
977 , p. 806
Downloaded by Lynh Nguyen (lynhn228@gmail.com)

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