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New Stereospecific Catalysts for Polymerizing Butadiene.

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(free from isotetrasilane). Results of determinations with
isotetrasilane will be published later. Combustion in a calorimetric bomb is suitable for disilane, which is readily condensed, and for tri- and tetrasilanes, which are liquids [4].
On account of its low b.p. (-1 11.6 "C), however, SiH4 could
only be burnt at constant pressure in a specially designed
combustion chamber [ 5 ] . This method was also applied to
disi1ane
Table 1 shows the heats of combustion (W,) at 20 "C and the
enthalpies of formation (WB) derived therefrom for silanes
at 20 "C.
The X-ray diffraction pattern showed complete absence of
crystallinity in the polymer. Catalytic hydrogenation of the
polymer (61 = 2.5) using Pd/CaC03 [2] was carried out at
room temperature in benzene. Hydrogen absorption ceased
at only 65 "/, of theoretical amount.
Determination of the degrcc of unsaturation by the iodine
chloride addition method [31 showed that 85 % of the vinyl
group reacted.
When the MoCIs was combincd with Ni(C0)4, the polymer
obtained with thc resultant catalyst was found unexpectedly
to be more than 85 % cis- I ,4-polybutadiene.
Table 1. Heats of combustion (Wp) and enthalpies of formation (WB)
of silanes at 20 "C
Received, July 15th, 1963
[Z 550/371 IE]
German version: Angew. Chem. 75, 858 (1963).
.
I
-835.1
& 0.7
g
liq
liq
liq
-11.3
-36.2
-54.4
-70.8
g
g
liq
liq
The reaction in the bomb yielded sc-SiOz, that in the combustion chamber gave amorphous SiOz. The difference in
enthalpy of these two forms of SiOz is important for the
calculation of the enthalpy of formation of SiHl and was
estimated by combustion of disilane in the calorimetric bomb
(Wp = -575.3 kcal/mole) and in the combustion chamber
(Wp = -568.9kcal/mole) allowing for the heat of evaporation
(5.0 kcal/mole); the value obtained was -5.7 kcal/mole.
Received, July 15th, 1963
[Z 554/387 IEI
German version: Angew. Chem. 75, 859 (1963)
[ I ] M . J. Ugier, Ann. Chim. Phys. [5] 20, 25, 37 (1880); H.von
Wartenberg, Z. anorg. allg. Chem. 79, 71 (1913); E. 0. Brimin
and H.M.Humphreys, J . physic. Chem. 61, 829 (1957).
[2] S. R. Gunn and L. G. Green, J. physic. Chem. 65, 779 (1961).
[3] F. F e h l , G. Kuhlhiirsch, and H. Lwhleich, Z . anorg. allg.
Chem. 303,294 (1960).
[4] G. Jansen, Ph. D. Thesis, Universitat Koln, 1960.
[ l ] D. Morero, S. &fltQmhroKio, L. Porri, and F. Clampelli,
Chim. e Ind. 41, 756 (1959).
[2] A. I. Yakuhchik and G. N . #;rotnova, Rubber Chem. Technol.
31, 156 (1958).
[3] T . S. Lee, I. M . Koltof, and M . A . Mnirs, J . Polymer Sci. 3,
66 (1948).
1,3-Dithiolane-2-thione-4,5-dione
By Dipl.-Chem. B. Krebs and Doz. Dr. G. Gattow
Anorganisch-Chemisches I nslitut der Universitat Gottingen
Dedicated to Prof. Dr. Brodtniann on the occasion of his
60th birthday
Interaction of equimolar quantities of SC(SH)2 [ I ] and oxalyl
chloride has given rise to I .3-dithiolane-2-thione-4,5-dione
( I ) for the first time and i n qtiantitative yield as beautifully
cristalline wine-red needles.
II
S
[5] H. Rohmer, Diploma Thesis, Universitat Koln, 1963.
New Stereospecific Catalysts for Polymerizing
Butadiene
By S. Otsuka and M. Kawakami
Research Laboratory, Japan
Synthetic Rubber Co., Yokkaichi (Japan)
We have found new stereospecific catalysts for polymerizing
butadiene which do not rely on organometal compounds of
Group I to I11 metals.
When a mixture of molybdenum pentachloride and cobalt
carbonyl was used as a catalyst, butadiene was polymerized
to a completely amorphous polymer which has a 1,Zcontent
(determined by the infrared analysis according to Morero [I])
of 99 % without fractionation. All operations were carried
out under nitrogen. A typical polymerization procedure is as
follows: A solution in benzene of dicobalt octacarbonyl
(0.25 mmole, 0.5 matom as Co) was added to a suspension of
molybdenum pentachloride (0.5 mmole) in benzene. The resulting slurry contained a black precipitate and was heated at
50°C for one hour, about 19 mole-"/, of carbon monoxide
being evolved. Polymerization of butadiene was effected by
this aged catalyst mixture at 40°C for 18 hours; yield: 60 %.
The intrinsic viscosity [?I of the polymer lay in the range 2-3,
depending upon the conditions of polymerization. Polymer
with [q] greater than 2 is a rubber-like solid which is soluble
in acetone and ether and very soluble in benzene giving a
highly viscous solution.
618
Adilute solution of (COC1)2 in CHC13 is dropped slowly
at 0 "C with exclusion of moislure into a solution of SC(SH)z
in CHCI3, when ( I ) is formed smoothly with immediate evolution of HCI. The reaction is completed by heating for 10 minutes at 50°C. After removal ol' theCHCI3,( I ) is recrystallized
from n-hexane (m.p. 6 6 " C , b.p. 9O"CjZ mm; d:5 = 1.890).
When heated at atmospheric pressure under nitrogen, ( I ) decomposes above 100 "Cinto ( ' 0 2 , CO, COS, and CS?. I t is readily soluble in CtIC13, CC14, benzene, ether, but only sparingly
soluble in paraffins; it is reiidily decomposed by polar solvents such as methanol or clhanol. Hydrolysis in water affords oxalic acid and trithiocwbonic acid (+ HzS -1- CSz), together with yellow polymerisation products. This hydrolytic
decomposition is also complcle within several hours on exposure of (1) to a moist atmosphere.
The visible spectrum (solvent : CC14, n-hexane) contains a
weak R-double band with niaxima at 522 and 540 mp, together with a strong K-band at 417 mp. The infrared spectrum (in CC14 and Nujol) hiis peaks at 1716 and 1724 (incompletely resolved, s), 1105 (s), 1000 (s), 958 (m), 800 (w),
526 (m), and 468 (w) cni..l.
X-ray diffraction studies (rotating crystal, Weissenberg
equator and Weissenberg eq ui-inclination photographs with
Cu-Kcc-radiation) about [OIO] and precession measurements
(@ = 30 ",Mo-K,-radiation) uhout [IOO]and [OOl] show that
( I ) crystallizes monoclinically with z = 8 in the space group
C;,.-P2/b
or Czh,--P21/h; a = 11.34 1 0.02,b= 5.220+
O.OI,andc= 19.39 I- 0.03 A ; $ .:96"50' ! 30'. X-raydensity:
1.886.
Received, July ISth, 1963
[Z 543/379 1El
German version: Angew. Chem. 75,978 (1963)
[ I ] G . Gattow and B. Krehs, %..anorg. allg. Chem. 321,143(1963).
A n g e w . Chem. intormil. Edit. 1 Vo/. 2 (1963) 1 N o . 10
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stereospecific, new, catalyst, butadiene, polymerizing
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