close

Вход

Забыли?

вход по аккаунту

?

a-Olefins from Ethylene.

код для вставкиСкачать
T h e phenacyl bromide behaves in a n analogous fashion, b u t
the iodide yields (2) in low concentration a n d leads t o acetophenone phenylhydrazone as t h e main product.
Received: February 3, 1970
IZ 148 IEI
German version: Angew. Chem. 82. 2 5 4 (1970)
[*I Prof. W. C. Stickler and W. C. Hoffman
Department of Chemistry, University of Denver
Denver, Colorado 80210 (USA)
[ I ] See, e . g . , E . VotoEek, Coll. czechoslov. chem. Comm. 2,
681 (1930); Chem. Abstr. 25, 1488 (1931).
[2] 0. Hess, Liebigs Ann. Chem. 232, 234 (1886).
[3] For the structure of ( 2 ) see: D . Y . Curtin and E. W. Tristrain, J . Amer. chem. Soc. 72, 5238 (1950). (Their review of
previous work contains, however, some historical and factual
errors.)
[4] H . D . Hart, M . S . Thesis, University of Denver, 1952;
W. C . Stickler, H. D . Hart, and P. Yin, J. Co10.-Wyo. Acad.
Sci. 1952, 34; W. C . Stickler, W . Epstein, and L . Gachic, ibid.
I953, 24.
[5] Cf. 0.L. Chapman e f al., J. Amer.chem. SOC.86,4968 (1964).
[6] We a re indebted to Prof. J . J . Schmidt-CollPrus and his
staff, University of Denver Research Institute, and Mr. R . H .
Williams, Univ. of Illinois, for obtaining th e spectra and aiding
us in their interpretation.
[7] A . Burawoy, J . chem. SOC. (London) 1937, 1865; e x . ,
C H-N =N-C6H 5 absorbs at 403 nm.
[8] T he dienophilic structure involving C=C can be arrived at
by considering either limiting resonance structures o r tautomeric forms.
phere of argon. T h e homogeneous solution is then transferred
t o a n autoclave a n d cooled t o --20 "C. Ethylene is introduced
i n t o t h e autoclave a t 1 2 a t m an d both pressure an d temperature ar e kept constant during the t i me o f reaction
(1 hour). After withdrawal of the ethylene at t h e reaction temperature the conversion can b e determined by weighing (increase in weight minus t h e solubility o f t h e ethylene in t he
reaction solution): 34.6 g, corresponding t o a conversion of
13.0 moles o f ethylene per liter o f reaction solution per hour.
T h e reaction solution was washed with water t o remove
catalyst; so me solid polymer (0.9%) was precipitated. T h e
organic phase was fractionated by vacuum distillation (see
Tab l e 1).
Received: February 4, 1970
IZ 149 IE]
German version: Angew. Chem. 82, 255 (1970)
~
~~~~
[*IDr. G . Henrici-Olive and Dr. S. Olive
Monsanto Research S.A.,
CH-8050 Zurich, Eggbuhlstrasse 36 (Switzerland)
[l] Homogeneous Catalysis at Ti(rv) Centers, Part 3. - Part 2:
G. Henrici-OlivP and S . Olive, J. Polymer Sci., Part B, in press.
121 G. Henrici-Olivd and S . OiivP, Angew. Chem. 79, 764
(1967); Angew. Chem. internat. Edit. 6, 790 (1967).
[3] C . Henrici-OlivP and S . OlivP, Advances Polymer Sci. 6, 421
(1969), and literature cited therein.
141 H . Bestian and E. Prinz, US-Pat. 2907805 (1959), Farbwerke Hoechst.
[5] H . Bestian and K . Clauss, Angew. Chem. 75, 1068 (1963);
Angew. Chem. internat. Edit. 2, 704 (1963).
Dicyclopropylacetylene by Fritsch-ButtenbergWiechell Rearrangement
a-Olefins from Ethylene111
By Gisela Henrici-Olivk a n d Salvador Olive'[*]
By Gert Kobrich a n d Dieter Merkel [*I [**I
Ethylene is rapidly converted in to solid polyethylene by t h e
two-component catalyst Cp2TiRC1,'RAICIz (Cp = cyclopentadienyl, R = alkyl) in toluene at O°Crz,31. Besriaii et a/.,
however, have shown that t h e major products a r e liquid
oligoethylenes - mainly 2-ethyl-1-olefins ( I ) having vinylidene terminal groups - when C12TiRCI/RAIC12 is used as
catalyst in CHzC12 as solvent a t -70 "C [4,51.
By systematically changing th e reaction conditions an d t h e
ligands on titanium we have n o w been able t o prepare
C6-c40 olefins (2) having predominantly vinylic end groups.
T h e best results were obtained by using t h e following procedure:
(CzH50)3TiCI (2 mmoles) is dissolved i n toluene (100 ml)
a n d treated with CzHsAIClz (10 mmoles) under a n atmos-
Table 1.
Fractionation of oligoethylene.
Fraction
Parts by weigl
Vjnylidene ( I )
No.
( %)
(%) [bl
1
2.3
2
3
4
5
6
7
8
9
10
13.7
11
16.0
2.0
12.0
6.7
8.0
9.5
13.4
15.5
0.9
56 [cl
8 4 [cl
112 [cl
150
175
195
215
225
292
465
solid
Reaction of 1-chloro-2,2-dicyclopropylethylene(Z),prepared
from dicyclopropyl ketone ( I ) by chloroolefination 111, with
n-butyllithium i n T H F between -110 an d +2OoC afforded
t h e hitherto unknown dicyclopropylacetylene ( 5 ) as a stable,
colorless liquid, beside 1,I-dicyclopropyl-1-hexene ( 4 ) .
Hydrogenation of t h e acetylene ( 5 ) over a Lindlar catalyst
proceeded almost quantitatively an d stereospecifically t o
give cis-l,2-dicyclopropylethylene( 6 ) 121.
T h e supposedcarbenoid intermediate (3) has n o t been detected
so far probably because t h e electron-repelling a n d bulky
cyclopropyl groups slow down metalation o f ( 2 ) , on t h e o n e
hand, an d accelerate decomposition of (3) [31 o n t h e other.
I
(C~H,),P=CHCI
100
>95
395
>90
2 9 0
390
290
>SO
%
>70
270
-
[a] Number average molecular weight, Mn, determined by vaporpressure osmometry.
lbl Percentage of molecules with vinyl- and
vinylidene end groups calculated from the absorption at 9 1 0 and 890
cm-1 resp.
[cl The first three fractions distilled together with the
toluene and were identified gas-chromatographically as I-butene,
I-hexene, and 1-octene.
Angew. Chem. internut. Edit. J Vol. 9 (1970)
No. 3
243
Документ
Категория
Без категории
Просмотров
0
Размер файла
119 Кб
Теги
ethylene, olefin
1/--страниц
Пожаловаться на содержимое документа