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An Organoboron Model System for the Fischer-Tropsch Synthesis.

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pended in 15 mL of anhydrous diethyl ether under argon; the addition is
c.irried out so as to maintain a gentle reflux. After 1 h, the excess lithium
I, filtered off and the amount of 4 is determined by double titration according to the procedure of Gilman et al. (161; yield >95%.
(20.1 MHz, CDCII): 6 = 131.9 (C-I), 121.0
[8] 6 b : "C-NMR
('J("C,D)=23.0 Hz, C-2), 26.1, 18.0 (R', R2).
[9] 3b: "C-NMR (20.1 MHz, [D6]DMSO/C2HSOH): 6 = 150.0 (C-2), 133.7
(C-I), 20.5, 18.5 ( R ' , R2).
[lo] 2b: "C-NMR (20.1 MHz, CDCI,): 6 = 153.1 (C-2), 107.4 (C-I), 23.8 (R',
R2).
[ I I] We thank Prof. Dr. H . Gunther and Dr. P. Schmiff fur the measurements
as well as for discussion of the preliminary results. Exact analysis of the
LH, 13C - , and 'Li-NMR spectra: H. Giinther, P. Schmitt, R. Dujardin,
A. Maercker, unpublished.
[I21 Cf. D. Seebach, R. Hassig, J. Gabriel, Helu. Chim. A C ~ 66
Q (1983) 308; R.
Hassig, D. Seebach, ibid. 44 (1983) 2269.
[ 131 A. Maercker, R. Dujardin, B. Engelen, W. Buchmeier, R. Seeger, unpublished.
1141 7b: b.p.=85--86"C/100 mbar; '%NMR(20.1 MHz, CDCI]): 6 = 131.6
(C-I), 123.6 (C-2), 20.7, 19.1 (R', R'), 16.9 (CH,).
[I51 8b: b.p.=102-I03"C/10
mbar: "C-NMR (20.1 MHz, CDCI,):
6=132.3 (GI), 125.8 (C-2), 22.3, 20.6 (R',R'). 14.3 (SCHs).
[I61 H. Gilman, A. H. Haubein, J . Am. Chem. SOC.46 (1944) 1515.
An Organoboron Model System for the
Fischer-Tropsch Synthesis**
By Roland Koster* and Mohamed Yalpani
Dedicated to Professor Heinz Hoberg on the occasion
of his 60th birthday
Since the discovery of the Fischer-Tropsch synthesis"]
there have been numerous and extensive studies, not only
from the standpoint of its technology[*] but also with regard to the reaction mechanism i n v ~ l v e d [ ~and
" * ~the
~ other
variants[3b1of the still very interesting C,-growth reaction.
However, in contrast to the many investigations of assumed part steps, the overall chain formation reaction cannot be followed with a suitable model system.
Herein we report on a quantitative,[41 reductive C l polymerization of carbon monoxide, present as mono-, dior trinuclear metal carbonyl, with 9-borabicyclo[3.3. llnonane (9-H-9-BBN)['] to give 9-alkyl-9-borabicyclo[3.3.l]nonanes (9-alkyl-9-BUN). The reaction proceeds according to
Eq. (a), giving 9-BBN derivatives with mainly linear alkyl
moieties. These have so far been identified u p to 9-decyl-9BBN (n = 10).
1 Mole of pentacarbonyliron with = 1 1 moles of 9-H-9BBN[@in e.g. mesitylene or n-nonane leads in a strong exothermic reaction within a few minutes on heating at
= 140°C to the formation of a black precipitate, whose
composition corresponds to the empirical formula
FeC2H3.5. Referred to 9-H-9-BBN, about one equivalent of
gas, consisting of = 213 Hz and = 113 CH4, is liberated.
Small amounts of ethane (< 2%) as well as traces of C3/C4hydrocarbons are also detectable (MS analysis). A colorless liquid fraction and a white solid can be recovered
from the reaction mixture.['] The liquid can be separated
gas-chromatographically into numerous 9-alkyl-9-BBN
compounds whose retention volumes and MS fragmentograms are consistent with those of authentic samples. The
solid product is the diboroxane (9-BBN)z0,[81an organoboron equivalent of the water formed in the FischerTropsch synthesis.-9-Alkyl-9-BBN mixtures of varying
composition, as well as the oxide (9-BBN)z0, can also be
obtained in an analogous way with Fez(C0)9 ( 2140°C),
with Fe3(C0)12( 2 1 3 0 ° C ) or with C O ~ ( C O(29OOC)
)~
according to Eq. (a).
The reaction mixtures contain, apart from the major
products with unbranched alkyl residues, also derivatives
with straight alkane chains not bound to C-1 (e.g. 9-see-butyl-9-BUN) and compounds with methyl-branched alkyl
groups (e.g. 9-isobutyl-9-BBN) (cf. Table 1).
Table 1. Relative yields [%I of 9-R-9-BBN from metal carbonyls and 9-H-9BBN [a]. Procedure: [7].
Alkyl
Catoms Name
1
2
3
4
5
6
7
8
9
n/5 Fe(C0)5
+
>
10
140OC
(2n+l)
- n/5
'Fe'
>
-
(
1
'
Methyl
Ethyl
Propyl
Isobutyl
sec-Butyl
Butyl
CCr-Isomery[c]
Pentyl
xC,-Isomers[c]
Hexyl
CC,-Isomers[c]
Heptyl
CC,-Isomers[c]
Octyl
CC,-Isomers[c]
Nonyl
CClu-komers[c]
Decyl
Residual alkyl
moieties [bl
>BH/CO-ratio
Fe(CO1 FedCO), Fel(C0),2
2.0
2.3
2.2
23
21.3
21.8
14.4
2.2
0.7
7.2
3.1
4. I
2.8
2.4
1.6
1.5
0.8
0.8
0.9
1.0
n. d.
0.7
12.7
42.9
14.5
8.4
1.3
0.4
4.4
2.0
2.4
1.9
I .4
0.8
1.0
0.4
0.6
n. d.
0.7
n. d .
0.4
16.8
50.0
16.1
10.0
I .3
0.6
5.0
2.0
2.7
1.3
I .4
0.8
0.8
I .4
0.6
n. d.
n. d.
n. d.
n. b.
6.0
46.7
17.4
11.7
1.6
0.7
5.6
2.2
3.0
1.4
1.6
0.8
0.8
0.3
0.5
n. d.
0.3
n. d.
n. d.
5.4
CO~(CO)~
1.9
24.4
13.6
10.3
2.1
1.0
5.7
3.9
2.9
3.7
1.6
2.5
1.7
I .o
I. I
n. d.
I .9
n. d.
n. d;
21.0
[a] G U M S analyses: G C peaks 10.3% ignored; n. d.=not determined. [b]
Separation from the highly viscous residue by cooling its pentane solution to
-78"C, and filtration. [c]ZC, isomers include all alkyl moieties with x carbons, but with the exception of straight chain alkyl residues bonded to the
boron atom via C-I.
9-H-9-BBN
nPB-o-BK
(9-BBN),O
9 -alkyl- 9 -BBN
[*I Prof. Dr. R. Koster, Prof. Dr. M. Yalpani
[**I
572
Max-Planck-Institut fur Kohlenforschung
Kaiser-Wilhelm-Platz I, D-4330 Miilheim a. d. Ruhr (FRG)
Boron Compounds, Part 67. We thank Mrs. F. Sagheb (Dept. Dr. Schomburg) for the gas-chromatographic separations and Mr. W. Schmdller
(Dept. Dr. Henneberg) for the mass spectrometric measurements.- Part
66: R. Koster, S. Penades-Ullate, W. V. Dahlhoff, Angew. Chem. 97
(1985) 508: Angew. Chem. In/. Ed. Engl. 24 (1984) 519.
0 VCH Verlagsgesellschaft m b H , 0-6940 Weinheim, 19x5
Fe,(CO), reacts with 9-deuterio-9-borabicyclo[3.3.1]non a r ~ e [ (9-D-9-BBN)
~~I
in mesitylene > 140°C to give 9-alkyl-9-BBN compounds, whose 9-alkyl moieties contain
only very little deuterium[''. Reaction of 9-D-9-BBN with
Co,(CO), in heptane at =9O"C, however, leads to formation of 9-perdeuterioalkyl-9-BBN compounds (degree of
deuteriation of the alkyl moieties: >95%). The alkyl
groups of the 9-alkyl-9-BBN compounds must therefore be
generated by reduction of the metal-coordinated C O ligands. Presumably metal carbenes and/or metal-alkene 7c-
0570-0833/85/0707-0572 $ 02.50/0
Angew. Chem. I n / . Ed. Engl. 24 (19x5) No. 7
Table 2. Relative vields 1%1 of 9-methvl-9-BBN and 9-ethyl-9-BBN as a function of the >BH/CO ratio
Carbonylmetal
co
compound [bl
(solvent)
[mmol]
9-H-9-BBN
[mmol]
>BH/CO
2.3
2.1
0.9
2.2
0.2
4.5
2.3
1.3
1.8
1.9
87
67.8
35.0
77.8
79.8
48.6
32.4
20.8
50.0
51.4
38.0
32.0
38.0
35.0
399.0
10.8
14.4
16.6
27.2
27.2
Yield [a]
9-Me-9-BBN
9-Et-9-BBN
[Oh1
IW
42.9
29.4
24.2
5.2
1.0
59.0
50.3
30.1
18.6
35.4
14.8
24.0
33.6
20.0
21.0
21.0
20.3
33.8
30. I
17.6
9-Me-9-BBN
9-Et-9-BBN
2.9
1.2
0.1
0.25
0.05
2.8
2.5
0.9
0.6
2.0
[a] G C peaks; conditions for separation: capillary column (36 m); dexsil300; injection block: 150°C; column: 40-280°C (6"/rnin). [h] Standard conditions: carhonylmetaf compound and 9-H-9-BBN in mesitylene ( M ) or in nonane (N) heated for t 1 h at Z 140°C. [c] Portionwise addition ( t 3 h) of solid 9-H-9-BBN to the
solution of Fe(CO), at 140°C. [d] Heated at t 9 O T .
complexes are formed as intermediates in the synthesis (cf.
Scheme I )
141
I+
1
1
+ 9-H-9-BBN
9-CH3- 9-BBN
CHZ
[5]
9-H-9-BBN
[6]
9-alkyl-9-BBN
Scheme I. Possible mode or the 9-alkyl-9-BBN formation
Different rates of the reduction and CO-insertion reactions lead, depending upon the amount of monomeric 9-H9-BBN available in solution, to varying amounts of 9-methyl-, 9-ethyl-, and higher 9-alkyl-9-BBN homologues.
Thus, at low >BH/CO ratios the amount of 9-methyl-9BBN drastically decreases, e.g. on slow addition of 9H-9BBN (cf. Tables 1 and 2).
We presume that the higher 9-alkyl-9-BBN compounds
(alkyl Z C,H,) are only formed on polynuclear metal clusters or on the surfaces of metal particles which separate
from the original homogeneous solutions of the metal carbonyls.
The composition of the 9-alkyl-9-BBN mixture depends
on the molar ratio of the reactants and on the reaction conditions, i.e. the temperature, the heating rate, or additives,
e.g. alkali metal alkoxides. The metal carbonyl/9-H-9BBN system is thus suitable as a readily variable, easily
accessible reaction mixture for the investigation of the
Fischer-Tropsch synthesis.
Received: March 27, 1985 [Z 1176 IE]
German version: Angew. Chem. 97 (1985) 6oo
CAS Registry numbers:
9R-9-BBN (R=methyl), 23418-81-7; 9R-9-BBN (R=ethyl), 52102-17-7; 9R9-BBN (R=propyl), 1127-78-2; 9R-9-BBN (R=butyl), 23532-74-3; (9BBN)?O, 74744-62-0; 9H-9-BBN, 280-64-8; Fe(Co)5, 13463-40-6; Fe2(Co)g,
15321-51-4: C O ~ ( C O )10210-68-1:
~,
Fe3(Co),2, 17685-52-8.
[I] Patent ( D R P 484337), entitled "Verfahren zur Gewinnung mehrgliedriger
Paraffi nkohlenwasserstoffe aus Kohlenoxyden und Wasserstoff auf katalytischem Wege", filed 60 years ago (July 22, 1925) by Franz Fischer and
Hans Tropsch (Miilheim a. d. Ruhr).
[2] Ullmanns Encyklopadie der Technischen Chemie, Vol. 14, 4th Edit., Verlag
Chemie, Weinheim 1977, p. 329-355; R. B. Andersen: The FischerTropsch Synthesis. Academic Press, London 1984.
[3] a) C . Masters, Adu. Organomet. Chem. 17 (1979) 61; C. K. Rofer-De
Poorter, Chem. Rea. 81 (1981) 447; G. Henrici-Olive, S. Olive: The Chem-
Angew. Chem. Inl. Ed. Engl. 24 (1985) No. 7
[7]
[8]
[9]
istry ofthe Catalyzed Hydrogenation of Carbon Monoxide. Springer, Berlin 1984; b) S. L. Suih, K. C. McMahon, L. M. Tau, C . 0. Bennett, J . Cafal. 89 (1984) 20; c) w . A. Herrmann, Angew. Chem. 94 (1982) 118; Angew. Chem. Int. Ed. Engl. 21 (1982) 117.
Compare the yields of the Fischer-Tropsch products with those of other
metal carbonyl reductions: A. Wong, J . D. Atwood, J . Organomel. Chem.
199 (1980) C 9 ; 210 (1981) 395; C. Masters, C. van der Woude, J. A. van
Doom, J . A m . Chem. Sac. 101 (1979) 1633.
a) R. Koster, Angew. Chem. 72 (1960) 626; h) R. Koster, P. Binger, Inorg.
Synth. 15 (1974) 141; c) cf. Houhen-Weyl: Methoden der Organischen
Chemie, Ed. X111/3a, 4th Edit., Thieme, Stuttgart 1982, p. 330; d) see
[ k ] , p. 339 f.
a) For determination of the hydride number ( H Z B B Y )the
, 9-H-9-BBN
consumed by the metal carbonyls was measured at G 140°C [6b]:
)~
Fe(C0)5 ( H Z s s N = 11); Fe2(C0)9 (20); Fe,(CO),> (26.5); C O ~ ( C O (16).
The consumption of open-chain alkyldiboranes(6) [5b,c] is greater ( H Z
[6h] > HZBRN);
complex mixtures of trialkylboranes, trialkylboroxines
and tetraalkyldiboroxanes; are formed; h) R. Koster, L. Synoradzki,
Chem. Ber. 117 (1984) 2850.
Experrmenlal: The yellow-orange slurry of 9-H-9-BBN [5b, c] (8.21 g, 67.8
mmol) and Fe(COjs (3.21 g, 6.16 mmol) (>BH : F e = 11.1;
>BH :CO=2.2: I ) in nonane ( = 8 mL) was heated slowly under protective gas; the color changed from orange-yellow through yellowish gray
(50-SOT) to black. At 2 8 0 ° C 4.5 mmol of gas (MS: 68.5% H2, 31.9Oh
CHI, = 1.3% C2Hh, = 1% C4HIO)were liberated. After stirring for =30
min (bath: = 140°C; exothermic reaction up to = 160°C) nonane (5.8 g ;
14 torr; bath: 5 7 0 ° C ) and a 9-alkyl-9-BBN mixture [ t1 g (calc. 0.96 9);
0.001 torr; bath: C90"Cl (S"B= 88.2) were distilled off (composition: cf.
Table 1) under vacuum. From the highly viscous residue by sublimation
in vacuo (0.001 torr; bath: 90- IOOT) 7.75 g(calc. 7.95 g) of colorless (9BBN)20 remained [MS: m/z=258; S"B= 59.31. After heating in boiling
heptane one obtains 520 mg Fe-containing black solid ( ~ 6 7 %
Fe).
See [Sc]. pp. 816, 819.
9-D-9-BBN [Sc] transforms at 2 140°C via dehydroboration/deuterioboration into partially deuterated 9-H-9-BBN compounds.
X-RaY Structure Determination of
[a-(PhenYlsulfonYl)benZYllithiumTetramethylethylenediaminejz:
Chirality of an a-Sulfonyl "Carbanion"""
By Gernot Boche,* Michael Marsch, Klaus Harms, and
George M . Sheldrick
Dedicated to Professor Rolf Huisgen on the occasion of
his 65th birthday
a-Sulfonyl "carbanions" ( R1R2C"-S02R3M @)play an
important role in synthetic chemistry."' The high acidity of
[*] Prof. Dr. G. Boche, M. Marsch
Fachbereich Chemie der Universitat
Hans-Meerwein-Strasse, D-3550 Marhurg (FRG)
Prof. G. M. Sheldrick, Dr. K. Harms
Institut fur Anorganische Chernie der Universitat
Tammannstrasse 4, D-3400 Gottingen (FRG)
[**I This work was supported by the Fonds der Chemischen lndustrie
0 VCH Verlagsgesellschaft mbH, 0-6940 Weinheim, 1985
0570-0833/85/0707-0573 $ 02.50/0
573
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