THE PREPAPATICM OP cis-CINHAi. aC ACIL

62 Pages·2009·1.3 MB·English

In presenting the dissertation as a partial fulfillment of
the requirements for an advanced degree from the Georgia Institute of
Technology, I agree that the Library of the Institution shall make it
available for inspection and circulation in accordance with its regu­
lations governing materials of this type. I agree that permission
to copy from, or to publish from, this dissertat.on may be granted by
the professor under whose direction it was written or, in his absence,
by the Dean of the Graduate Division when such copying or publication
is solely for scholarly purposes and does not involve potential f i­
nancial gain. It is understood that any copying from., or publication
of, this dissertation which involves potential gain will not be allowed
without written permission.
THE PREPAPATICM OP cis-CINHAi.aC ACIL
DTBROULh ALNL ITS C;/Ti£i:SIOJ
TO beta-BRQ.v;QSTIREHE
A TRESIS
Presented to
the Faculty of the Graduate Division
by ..<,
%
Spyros Pi Theophilou
In Partial Fulfillment
of the Requirements for the Degree
Master of Science in Chemistry
Georgia Institute of Technology
June, 195U
THE PRiiPAE" TIOi-I OF c i s - C I N I I M IC ACID
DIBROlimi
Ai:D ITS COi VERSION
TV beta-BRODOSTY vLrjE
Approved:
Date Approved by Chairman: ^fA/YLj ^) ^ H~
The author wishes to express his appreciation to his brother
Constantine and sister Emily for their financial aid during the course
of this investigation. He also wishes to thank JJr. Erling Grovenstein.
Jr._, who suggested this problem and assiduously guided it to completion,
for many stimulating discussions .and unbounding encouragement.
i ii
TABLE OF COii'TEE'TS
Page
ACKIFJ .vLEDGEIJEETS ii
LIST OF TABLES iv
OF ILLUSTRATI0:-IS v
L I ST
SFXiARY vi
I. DISCUSSION
P r e p a r a t i on of c i s - C i n n a m ic A c id 1
P r e p a r a t i on of c i s - C i n n a m ic A c id Dibrornide 5>
Conversion of c i s - C i n n a m ic A c id Dibrornide to
b e t a - Br om o s t,y r en e 7
I I. EXFERLIFHTAL DETAILS
P u r i f i c a t i on of Solvents 13
P r e p a r a t i on of c i s - C i n n a m ic A c id 19
I n f r a r ed A n a l y s is of c i s- a nd t r a n s - C i n n a m ic Acids 2i|
P r e p a r a t i on of c i s - C i n n a m ic A c id Dibrornide 30
Conversion of c i s - C i n n a m ic A c id Dibrornide to
beta—firQiiiostyrene 39
I n f r a r ed A n a l y s is f or c i s - t r a ns Isomers of b e t a-
Bran o s ty re ne h3
BIBLIOGRAPHY 5l
iv
LIST 01 TABLES
Table Page
1. Olefins from the Alkali r.ietal Salts of cis-Cinnamic
Acid Dibromide 9
2. Olefins from the Sodium Salt of trans-Cinnamic Acid
Dibromide 10
3. Radiation Data and Characteristics of Lamp Type LL 17
k» Infrared Data of cis- and trans-Cinnamic Acid Solutions
for Various Concentrations at the Four selected ,..a:.ir.ia .... 26
5>. Per Cent Held of cis- and trans-Cinnamic Acids Obtained
from Irradiation Experiments 2y
6. Lei ting Points of cis- t r an s - C innam i c Acid Dibroiiiide
Mixtures in Various Proportions 37
7. Optical Densities for Various Compositions of cis- and
t r a n s -b e t a - Br om o s ty r e n e s at Four ave Lengths I4.8
8. Optical Densities for tie Prepared beta-Bromostyrenes
at Four -.ave Lengtrs I4.9
9. Per Cent of c i s -b e t a - B r om o s ty r e n e in tiie beta-Bromostyrenes
from the Sodium or Potassium Salts of cis- and trans-
Cinnamic Acid Dibromides 5>0
V
LIST OF ILLUSTRATIONS
F i g u re Pagi
1. Conversion of t r a n s - C i n n a m ic Acid to cis_-Ginngjnic
A c id upon I r r a d i a t i on 1;
2. The S t e r e o s p e c if ic t r a ns j J e c a r b o x y l r t i ve E l i m i n a t i o ns
0I" £JL?~ anc^
t r a n s -C inn ami c A c id Libromides to b e t a-
Br om os ty r e ne s 12
3. Schematic Diagram of quartz C e ll vrith IJercury Lamp .. lo
i;. I n f r a r ed opectra of ' c i s- and tr an s - C i nn am i c A c i ds in
Carbon D i s u l f i de 25'
5. I n f r a r ed s p e c t ra of c i s- and t r a n s - C i n n a m ic A c id
Dibrornide in Carbon D i s u l f i de 3b
6. Mixed liixtures
Llelting P ^ i nt Curve upon S y n t h e t ic of
cis- anu t r a n s - C i n n a m ic A c id Dioramides 38
7. Apparatus used f or i t e c r y s t a l l i ^ a t i on of b e t a-
Bromostyrenes J4.6
8. E m p i r i c al C a l i b r a t i on Curves f or Infrared. A n a l y s is
of S y n t h e t ic ..-i..tures of c i s- and t r a n s - b e t a-
Bromostyrenes hi
vi
SUI&iARY
The purpose of this investigation was to improve the method of
preparation of cis-cinnamic acid dibromide and to study the stereochem­
istry of the c inversion of this compound to beta-bromostyrene, in the
solvents absolute ethanol, dry acetone, and water.
The initial step of this work was the irradiation of trans-cinnamic
acid in a saturated methanolic solution with light from a quartz mercury
lamp. The resulting mixture of cis- and trans-cinnamic acids was analysed
by an infrared technique. The conversion to cis-isomer was found to be
5>1 - 2 per cent in a 10 hour period of irradiation.
The separation of tne two isomers was effected by fractional ex­
traction and crystallization from n-hexane. The crude cis-cinnamic acid
was further purified through its aniline salt.
An improved method of preparation of cis-cinnamic acid dibromide
was devised. This consisted of addition of bromine to cis-cinnamic acid
in glacial acetic which was about one molar in hyorogen bromide. The
separation of cis-cinnamic acid dibromide from its higher melting diaster-
eoisoiner was effected by extraction with carbon disulfide followed by re-
crystallization from n-hexane. The yield of cis-cinnamic acid dibromide
was 5>0 per cent of product of m.p. 86.0-92.3'° which fr^m a mixed melting
point curve was calculated to be 95•5 - 1.0 per cent cis-cinnamic acid
dibromide.
Alkali metal salts of cis-cinnamic acid dibromide were converted
to beta-bromostyrene by heating in appropriate solvents.
v ii
The r e s u l ts are shown in the t a b le below.
O l e f i ns from the A l k a li L e t al S^lts of
c i s - C i n n a m ic A c id Dibromide
Solvent Composition of Y i e ld of beta- Comp o s it Ion of
cinnamic a c id bromostyrene b e t a - br omo s t yr e ne
d i b r o m i de c is t r a ns
% c i s - d i b r o m i de
Acetone 95.5 - 1.0 85.0 U.7 95.3
Abs. e t h a n ol 95-5 - 1.0 6U.7 2.6 97.2
..ater 91.0 - 1.0 8U.0 U.3 95.2
C a l c u l a t i o ns show t h at a ll of the c i s - b e b a - b r o m o s t y r e ne formed in
the r u ns in dry acetone and a b s o l u te etnanol can be a t t r i b u t ed to the
t r a n s - c i n n a m ic a c id dibromide p r e s e nt in the s t a r t i ng m a t e r i a l. I1 or the
r un in water the p r o d u ct c o n t a i n ed about 3 per cent of c i s - b e t a - b r o m o s-
t y r e ne w ^ i ch is c a l c u l a t ed to a r i se f r om the c i s - c i n n a m ic a c id dibromide
i t s e l f. The g r e a t er tendency of c i s- over t r a n s - c i n n a m ic a c id dibromide
to undergo d e c a r b o x y l a t i ve e l i m i n a t i on by a s t e r e o s p e c i ! ic concerted
trans-mecnanisai is a t t r i b u t ed to l e ss s t e r ic h i n d r a n ce in the c o r r e s­
ponding t r a n s i t i on s t a te f or c i s - c i n n a m ic a c id d i b r o m i d e.
1
CHAPTER I
DISCUSSION
P r e p a r a t i on of c i s - C i n n a m ic A c i d. — cis-Cinnamic a c id was prepared in
t he present work: by i r r a d i a t i on •£ m s t h a n o l ic s o l u t i o ns of trans-cinnaniic
a c id w i th u l t r a v i o l et l i g ht f r om a q u a r tz mercury arc lamp. This s y n t h e­
s is of c i s - c i n n a m ic acid was f i r st e f f e c t ed by Stoenner"'" who I r r a d i a t ed
a benzene s o l u t i on of t r a n s - c i n n a n i ic a c id f or e i g ht days .vith u l t r a v i o l et
l i g ht to give a 2£-30 per cent y i e ld of c i s - c i n n a m ic a c id (m.p. 58°).
L a t e r, Guy , w o r k i ng on i n f r a r ed a b s o r p t i on and Raman spectra of c i s-
and t r a n s - c i n n a m ic a c i d s, r e p e a t ed Stoermer1s method of p r e p a r a t i on of
c i s - c i n n a m ic a c i d. Havinga and nivard-^ i r r a d i a t ed a d i l u te s o l u t i on of
t r a n s - c i n n a m ic a c id in benzene f or s ix days w i th a mercury lamp, but
gave no statement of y i e l d.
Tanasescu'
a c i d, s t a t es t h at a s o l u t i on of o - n i t r o c i n n a m ic a c id ( in e t h yl a l c o h o l,
acetone, p y r i d i n e, e t h e r, e t c .) exposed to sun l i g ht is r a p i d ly c o l o r ed
r e d, b ut although i n s o l a t i on was c o n t i n u ed f or several weeks there was
no f u rt er change in the s o l u t i o n, ho e x p l a n a t i on of t r e se r e s u l ts is
given by tne author.
(1) R. Stoermer, Ber., If2, 1875-71 ( l ° 0 y ).
(2) hi. J. Guy, B u l l. Soc. Chim. ( F r a n c e ), 731-U2 (19U9).
(3) E. Havinga ano. R. J. F. N i v a r d, Rec. Trav. C.-i,-. m ., o7, GUo-5'U
(19U3).
(ii) J. Tanasescu, B u l l. Soc. Chim., U l, 107U (1927).