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New Aspects of the Hydroformylation Reaction.

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in two or three polycistronic segments of the genome may
be of special significance. It is conceivable that a genetic
organization of this kind is a necessary requirement
not only for aggregate formation but, particularly, for
the formation of the “right” protein complex, i.e. it is
needed to control its stoichiometry and/or architecture.
According to this notion the fatty acid synthetase complex of yeast would be assembled from two to three
dissimilar component complexes, the synthesis of which is
subject, in each case, to the particularly critical control
implied in a linked arrangement of their respective genes.
It is possible that the synthesis of the component complexes is also subjected to some kind of mutual co-ordination. This could take the form of typical eucaryotic control
mechanisms at the translation level.
Lecture at Dortmund on November 8,1971 [VB 327IEl
German version: Angew. Chem. 84,124 (1972)
[I] A . Hagen, Dissertation, Universitat Miinchen 1963
[2] E. Schweizer, L. Kuhn, and H . Castorph, Hoppe-Seylers Z. Physlol.
Chem. 352, 377 (1971).
New Aspects of the Hydroformylation Reaction
By Jiirgen Falbe“’
The catalytic reaction of olefins with carbon monoxide
and hydrogen to give aldehydes was discovered in 1938 by
0. Roelen (Ruhrchemie). It has become known as hydroformylation, the 0x0 synthesis, or the Roelen reaction.
The development of the petrochemical industry, through
which lower olefins have become available in sufficient
quantities at reasonable prices, provided the basis for the
world-wide exploitation of the 0x0 synthesis in large
production plants. In 1970 the annual world capacity
for 0x0 products amounted to about 2.7 x lo6 t.
The initially formed aldehydes are hydrogenated to
alcohols that are used primarily as solvents and as starting
materials for the production of plasticizers and detergents.
[*I Dr. J. Falbe
Ruhrchemie AG
42 Oberhausen-Holten, Postfach 35 (Germany)
About 80% of available production capacity is utilized
for conversion of propylene into butyraldehydes.
However, only about two thirds of the propylene is
actually transformed into the desired n-butyraldehyde,
the rest giving isobutyraldehyde as well as other byproducts and further reaction products. The reasons for
by-product formation were studied and mechanistic interpretations offered. In order to increase the selectivity
of the reaction, the tetracarbonylhydridocobalt used as
catalyst was modified by replacing the complexed carbon
monoxide by compounds of trivalent phosphorus. Although the use of phosphanes“] does reduce the amounts
of isobutyraldehyde and various higher boiling compounds, hydrogenation of the olefin to the paraffin is
promoted. Diphosphacyclopentenones[’] that have been
investigated at Ruhrchemie lessen the formation of
higher boiling compounds, esters, and alcohols and
increase the yield of n-butyraldehyde ; however, they
bring about no reduction in the proportion of isobutyraldehyde. Moreover, the increased catalyst costs incurred by
catalyst modification counteract the economic advantages
of enhanced selectivity.
Attempts were therefore made to cleave isobutyraldehyde
into products that can be used again in the 0x0 synthesis.
It was found that partial oxidation or steam reforming
affords a synthesis gas that can be re-used in 0x0 plants[31.
Isobutyraldehyde can also be cleaved into propylene,
carbon monoxide, and hydrogen[41(reversal of the 0x0
synthesis) on a fixed-bed noble metal catalyst at
250-350°C.
The reaction products can be recycled
into the 0x0 synthesis. This process has been developed
on a pilot-plant scale.
Lecture at Marl on December 22,1971 [VB 330 IE]
German version : Angew. Chem. 84,172 (1972)
[I] L. G. Canneff,L. M . Slaugh, and R. D. Mullineaux, DAS 1186455
(1960), Shell.
[2] J . Fafbe, H . nmmes, J . Weber, and W Weisheit, Tetrahedron 27,
3603 (1971).
[ 3 ] J . Fafbe and D. Hahn, German Pat. 1809727 (1968), Ruhrchemie;
F . Schnur, J . Falbe, E . Prijtt, and D. Hahn, DAS 1767261 (1968),
Ruhrchemie.
[4] J . Fafbe, H . mmrnes, and D. Hahn, Angew. Chem. 82, 181 (1970);
Angew. Chem. internat. Edit. 9, 169 (1970); Oil Gas J. of Nov. 23,
1970, p. 59.
SELECTED ABSTRACTS
Paramagnetic anisotropy of transition metal and rare earth
compounds and some minerals is surveyed in a paper by
W d e w Horrocks j r . and W d e w Hall. Introductory
sections on the theory of diamagnetism and paramagnetism
are followed by a fairly detailed description of the most
simple and versatile method of measuring magnetic
anisotropy : Krishnan’s critical torque method. Finally,
a documentation of compounds is given for which paramagnetic anisotropy data were available up to 1969
and partly into 1970, together with the pertinent references.
[Paramagnetic Anisotropy. Coord. Chem. Rev. 6, 147 to
186 (1971); 228 references, 4 figures, 1 table]
[Rd 423 IE -H]
Angew. Chem. internat. Edit. 1 Vol. I 1 (1972) No. 2
The photochemistry of adicarhonyl compounds in oxygenfree solutions is the subject of a review by B. M. Monroe.
Cleavage of a C-C bond is favored in the vapor phase,
whereas in the condensed phase hydrogen abstraction
preferably takes place. Only sufficiently strained compounds or compounds which can afford sufficiently stable
radicals give decarbonylation products. The review deals,
inter alia, with the excited states of a-dicarbonyl compounds and with photochemical reactions of a-diketones,
a-keto acids, and a-keto esters. [The Photochemistry of
a-Dicarbonyl compounds. Advan. Photochem. 8, 77-108
(1971); 120 references]
[Rd 438 IE -MI
155
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