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Dimerization of Propylene with Catalysts Exhibiting Activities Like Highly-Active Enzymes.

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reacts with sodium methoxide in methanol to give a bright red phosphonium ylide. which yields, e. g., with benzaldehyde a chromatographically separable 1 : l mixture of (0-and (Z)-6.8-dimethyl-4-styrylazulene(yield 69%).
[4] C Wiftig, Bull. SOC.Chim. Fr. 1971, 1921; B. M. Trosr, L. S. Melvin, Jr.: Sulfur Ylids. Organic Chemistry, Vol. 31. Academic Press, New York 1975.
131
Dimerization of Propylene with Catalysts Exhibiting
Activities Like Highly-Active Enzymes
By Borislav Bogdanovik, Bernd Spliethoff; and Giinther
Wilkef*]
u
h
c
(CH3)2N O H
d
e
N3 C 1 B r
f
[(C6H,)3pJ BF?
azulene derivative (7) (blue needles). The structure of (6) was
established primarily by analysis of the 'H-coupled I3CNMR spectrum. Formation of compound (6) corresponds to
that of the methylenecyclohexadiene intermediates detected
in the Sommelet-Hauser rearrangement of o,o'-disubstituted
benzyl-dimethylsulfonium and -trimethylammonium
c H3
C H3
J'CH3
CH3
In 1963 we discovered soluble catalysts which dimerize
ethylene and propylene with high activity, even at - 20 "C at
normal pressure1'].As catalysts we have employed, inter alia,
a-allylnickel halides in combination with Lewis acids such
as EtAlCl,. The dimerization of propylene can be controlled
within wide limits by addition of phosphanes having different electronic and, especially, steric properties, so that dimers
of various structures can be prepared at will['].The olefin dimerizations were performed in CH2C12or C6H5C1.We have
quoted the activity of the catalysts in the dimerization of propylene at normal pressure and - 20 "C for 3-6 kg product/
(g Ni. h).
In later experiments we established that the previously
found, but nevertheless considerable activity was apparently
exclusively determined by the reaction conditions such as
stirring, cooling, and gas feed, even though relatively small
amounts of catalyst were employed. As we have now found,
the activity is in fact about one thousand times higher. The
experiments for determining such high activities were performed as follows:
100 ml of C&,Cl, 350 g (8.33 mol) of 99.8% propylene,
and 0.6 g (4.72 mmol) of EtAIClz are mixed at temperatures
between -45 and -75 "C). The relatively large amount of
EtAlCI, should ensure that traces of impurities are trapped
(under the conditions given, EtAlC1, does not react with propylene). The vigorously stirred mixture is then treated with a
solution of 0.0023 g ( 5 ymol) of =-C3H5NiBrP(C6HII)3 in 1
ml C6H,C1 (prepared by multiple dilution of aliquot
amounts). A strongly exothermic reaction immediately sets
in, so intensive cooling is necessary to keep the temperature
of the reaction mixture constant. After 30 min the reaction is
terminated by passage of gaseous NH3, excess propylene
(250-300 g) is bubbled off, and the product worked up. Table 1 lists the results of experiments at various temperatures.
Table 1. Catalytic dimerization of propylene.
Unlike these intermediates, (6) does not undergo thermal
rearrangement; however, acid-catalyzed rearrangement (1%
HC1O4 in CH30H) regenerates the azulene system to give
4,6,8-trimethyl-1-(methylthiomethyl)azulene (8) (blue needles).
Physical data of the new compounds are compiled in Table 1.
T
["C]
g Product/
( 5 pmol cat.
x 30
-75
-65
-55
kg Product/
(g Ni-h)
mol C3H6/
(mol Ni.h)
[a1
min)
22
47
84
Turnover
number/s
152
324
580
209 524
447 619
800000
60
130
230
Received: April 28, 1980 [Z 514 IE]
German version: Angew. Chem. 92, 635 (1980)
[a] Turnover number = reaction steps at the active center; here: molecules of
propylene/alom Ni (approx. values).
CAS Registry numbers:
.
(2), 74465-56-8; (31, 74465-58-0; (4a). 74465-59-1; (4b), 74465-60-4; ( 4 ~ )7446561-5; (4d), 74465-62-6 14e). 74465-63-7. ( 4 n , 74465-65-9; (6), 74465-66-0; (71,
14465-67-1; (8), 74465-68-2
As expected, in the temperature range quoted the amount
of product/30 min doubles on increasing the temperature by
10 "C. The composition of the products is practically independent of the temperature, in contrast to catalysts in which
[ I ] S. Kurokawa, T Saro. T Noguchi, K. Yano. Bull. Chem. SOC.Jpn. 48, 1559
(1975). V. B. Mochalin, Yu. N. Porshner, Usp. Khim. 46, 1002 (1977); Russ.
Chem. Rev. 46, 530 (1977), and further references therein; K. Hafner, W.
Rieper, unpublished.
[Z] K. Hajner, H. Pelster, H. Pafzelr, Justus Liebigs Ann. Chem. 650, 80
(1961).
622
0 Verlag Chemie, GmbH, 6940 Weinheim, 1980
[*] Prof. Dr. B. Bogdanovic, Ing. (grad.) B. Spliethoff, Prof. Dr. G . Wilke
Max-Planck-Institut fur Kohlenforschung
Kaiser-Wilhelm-Platz 1, D-4330 Miilheim-Ruhr (Germany)
["I
Activity = amount of reacted substrate/(catalyst unit x unit time).
0570-0833/80/0808-0622
$ 02.50/0
Angew. Chem. Ini. Ed. Engl. 19 (1980) No. 8
(f-C4H9)P(i-C3H7)2
was employed as steering ligandtZ1.In the
present case we obtained, besides 10-15% of higher olefins,
dimers of the following composition: 18% 4-methyl-I-pentene, 1-3% cis-4-methyl-2-pentene, 76% 2,3-dimethyl-l-butene, 4% 2-methyl-l-pentene, as well as traces of other isomers.
The values in Table 1 already show that the activity of the
catalyst is higher by a factor of about 100 even at - 55 "C
than previously quoted for - 20 "C. Assuming a doubling of
the activity/lO"C, gives an activity of ca. 6000-7000 kg
product/(g Ni .h) and hence the factor 1000. For a comparison with enzyme activities, appropriate experiments had to
be performed at 25 "C. As experiments under pressure have
at this temperature the catalysts are fully active,
though a determination of the actual activity under pressure
can be achieved only with considerable effort, owing to the
limitations of the apparatus. Calculation as above gives a
value of ca. 150 x lo3 kg/(g Ni. h) and a turnover number/s
of ca. 60000; the corresponding data for enzymes13] are:
hexokinase 100, catalase 80000, carboanhydrase 600 000.
The activity of the catalyst diminishes at higher conversions, probably because of traces of impurities; nevertheless,
in one experiment at -45°C we have achieved turnover
numbers of lo6 mol propylene/mol of catalyst; on terminating the reaction the activity had fallen to about 10% of the
activity during the first 30 min.
If, under otherwise identical conditions, propylene is allowed to react with a catalyst not containing phosphane, the
activity is only ca. 1/15 of that quoted above, i. e. the phosphane not only exerts steering properties but also effects considerable activation. Generally, however, this catalysis would
also appear to be a further example of the phenomenon already observed several times, i. e. that the product selectivity
increases with increasing catalyst activity[41.To our knowledge the systems described here are the most active synthetic
homogeneous catalysts known to date.
We have investigated the solubility of difficultly volatile
biochemical substances in compressed fluid solvents using as
example the model substance a-tocopheryl acetate (vitamin
E acetate) in C02. For the measurements, a newly developed
optoelectrical methodI'l was used which enabled experimental determination of relatively low solubilities (for older
methods see 139.
From the clouding points of a mixture measured at various
pressures and temperatures a family of p ( T ) mixing curves
was constructed for each mixture examined. The curves in
Figure 1 are continuous between 20 and 50°C and do not
show any discontinuity in the neighborhood of the critical
temperature of COz (ca. 31 "C). This would indicate a continuous transition between the liquid-liquid and liquid-gas
phase equilibria (for an explanation of these phenomena
see 14.5.81).
I
15
Received March 14, 1980 [Z 516 IE]
German version: Angew. Chem. 92, 633 (1980)
CAS Registry numbers:
Propylene, 115-07-1. EtAIC12 56343-9 mr-C,H5NiBrP(CoH,,),. 4731 5-25-3
[ I ] a) G. Wdke. US-Pal. 3379706 (1963), Studiengesellschaft Kohle; b) B. Bogdanouic, G. Wilke. Brennst. Chem. 49, 323 (1968).
[2] G. Wilke In M . Tmrsui: Fundamental Research in Homogeneous Catalysis.
Val. 3. Plenum Press, New York 1979, pp. 1 ff.
[3] H. Winkler in K. Hauffe: Katalyse. de Gruyter, Berlin 1976, p. 218.
[4] W. Brenner, P. Heimbach, H:J. Hey, E. W. Mziller, G. Wilke, Justus Liebigs
Ann Chem. 727. 161 (1969), pp. 170. 171 therein.
300
TIT
35
LO
I
clmol dm-3 .lo-*
2
L
10
20
6
8
10
1
250 -
L
0
f!
P
200 -
150 -
100 -
Dr. Z. Alwani
Lehrstuhl fur Physikalische Chemie I1 der Universitft Bochum
Present address: Thyssen-Maschinenbau GmbH
D-5810 Witten-Annen (Germany)
Angew. Chem. Int Ed. Engl. 19 (1980) No. 8
30
From the p ( T ) curves (Fig. 1) the solubilities were determined as a function of pressure at a given temperature; sim-
By Ziad Alwani'']
Industrial methods have recently been developed for the
extraction of natural products with supercritical or fluid solvents at pressures of up to ca. 400 bar (cf. ['I). As examples
might be mentioned the decaffeination of coffee, the production of hop extract, and the extraction of spices. In the construction of chemical plant for high-pressure extraction, a
knowledge of parameters such as, inter alia, extraction rate
and solubility data, is of paramount importance.
["I Based on a lecture delivered at the GDCh-Hauptversammlung in Berlin,
September 12, 1979.
25
Fig. 1. p ( T ) Curves for a-tocapheryl acetate in CO, at several constant concentrations [wt-%I. CP=critical point.
Solubility of Nonvolatile Biochemical Substances
in Compressed Carbon Dioxide'"]
['I
20
30
LO
50
clg-dm-3
Fig. 2. c @ ) Curves for a-tocopheryl acetate in CO1 at several constant temperatures.
0 Verlag Chemre, GmbH, 6940 Weinheim, 1980
0570-0833/80/0808-0623
$ 02.50/0
623
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