Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2000-07-03
2001-10-30
Padmanabhan, Sreeni (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S451000, C568S909000
Reexamination Certificate
active
06310261
ABSTRACT:
The present invention relates to a process for preparing aldehydes and alcohols by hydroformylation of olefins in the presence of catalyst complexes comprising a metal of group VIII of the Periodic Table of the Elements and as ligand a phosphorus-free, high molecular weight modified polyamine which is essentially insoluble in water and recycling of the catalyst complex remaining in the bottoms from the distillation of the reaction mixture to the hydroformylation reaction.
The hydroformylation of olefins using carbon monoxide and hydrogen in the presence of transition metal catalysts has already been studied very well. Although &agr;-olefins can be hydroformylated very well using rhodium-containing phosphine-modified catalysts (cf. J. Falbe, Ed.: New Syntheses With Carbon Monoxide, Springer, Berlin 1980, p. 55 ff), this catalyst system is not very suitable for internal and branched internal olefins nor for olefins having more than 7 carbon atoms (cf. Falbe, p. 95 ff). Thus, internal carbon-carbon double bonds are only hydro- formylated very slowly in the presence of such a catalyst. Since the hydroformylation product is generally separated from the catalyst homogeneously dissolved in the reaction system by distillation and the boiling point of the aldehyde formed in the hydroformylation increases with increasing number of carbon atoms and chain length to temperatures at which the rhodium-phosphine-containing catalyst decomposes, this hydroformylation method is not economical for the hydroformylation of olefins having more than 7 carbon atoms.
In contrast, internal and branched internal olefins can be advantageously hydroformylated using “naked” rhodium, i.e. using rhodium compounds which are not modified with phosphorus-containing ligands such as phosphines or phosphites and are homogeneously dissolved in the hydroformylation medium. Such rhodium catalysts which are not modified with phosphines or phosphites and their suitability as catalyst for the hydroformylation of the abovementioned classes of olefins are known (see Falbe l.c., p. 38 ff). The terms “naked rhodium” or “naked” rhodium catalysts are used in this application for rhodium hydroformylation catalysts which, in contrast to conventional rhodium hydroformylation catalysts, are not modified with phosphorus-containing ligands such as phosphine or phosphite ligands under the conditions of the hydroformylation. Ligands in this sense do not include carbonyl or hydrido ligands. In the specialist literature (see Falbe l.c., p. 38ff), it is assumed that the rhodium compound HRh(CO)
4
is the catalytically active rhodium species in hydroformylation using “naked rhodium catalysts”, although this has not been unambiguously proven owing to the many chemical reactions occurring in parallel in the hydroformylation zone. It is only for the sake of simplicity that use is also made of this assumption here. The “naked” rhodium catalysts are formed under the conditions of the hydroformylation reaction from rhodium compounds, e.g. rhodium salts such as rhodium(III) chloride, rhodium(III) nitrate, rhodium(II) acetate, rhodium(III) acetylacetonate, rhodium(III) sulfate or rhodium(III) ammonium chloride, from rhodium chalcogenides, such as rhodium(III) oxide or rhodium(III) sulfide, from salts of rhodium-oxygen acids, for example the rhodates, from rhodium-carbonyl compounds such as dicarbonyl- rhodium acetylacetonate or cyclooctadienerhodium acetate or cyclooctadienerhodium chloride in the presence of CO/H
2
mixtures which are generally referred to as synthesis gas. The procedure for hydroformylations using “naked” rhodium is described, for example, in the following references: U.S. Pat. No. 4,400,547; DE-A 33 38 340; DE-A 26 04 545; WO 82/03856; Chem. Ber. 102, 2238 (1969); Tetrahedron Lett. 29, 3261 (1968); Hydrocarbon Process. 85-86 (1975), EP-A 588 225, WO 95/25080, EP-A 695 734, WO 96/16012, WO 97/30016, DE-A 19608559, EP-A 885 183.
However, hydroformylation using “naked” rhodium also has the disadvantage that, as a result of the thermal stresses in the distillative work-up of the hydroformylation product, the thermolabile rhodium catalyst (cf. U.S. Pat. No. 4,400,547) is partly decomposed to metallic rhodium which deposits on the walls of the reactor and pipes. The precipitated rhodium metal cannot be returned to the hydroformylation reaction since it cannot be converted into the catalytically active rhodium compound under the hydroformylation conditions. The rhodium losses resulting from this chemical behavior of the “naked” rhodium catalysts have hitherto prevented greater industrial use of this process.
DE-A 33 38 340 and U.S. Pat. No. 4,400,547 describe processes for hydro-formylation by means of “naked rhodium catalysts” in which a phosphine or phosphite is added to the reaction product from the hydroformylation to prevent precipitation of rhodium. These phosphorus compounds form phosphine or phosphite complexes with the rhodium catalyst and thus protect it from thermal decomposition during the course of the distillative work-up of the hydroformylation product. After the distillation is complete, the rhodium-containing distillation bottoms are treated with an oxidizing agent so that the rhodium is set free in catalytically active form from the phosphine or phosphite complexes in question and the phosphine or phosphite ligands are oxidized to the corresponding phosphine oxides and phosphates which do not form rhodium complexes under hydroformylation conditions. The oxidized distillation bottoms are then reused as catalyst for the hydroformylation. The oxidized phosphorus compounds formed in the oxidation generally do not interfere in the hydroformylation, although the process does result in accumulation of the oxidized phosphorus compounds in this hydroformylation circuit. Apart from these oxidized phosphorus compounds, the high-boiling components (e.g. aldol condensation products of the aldehydes) also accumulate in the catalyst circuit in this method of operation since they cannot be distilled off with the products and thus need to be bled off from the catalyst circuit.
According to U.S. Pat. No. 4,252,678, homogeneous, colloidal metal clusters of the elements rhodium, ruthenium, osmium and iridium which are bound to a polymer are used as catalysts for hydroformylation. Polymers which are mentioned as being usable for this purpose are vinyl polymers containing alkenyl, phosphine, phosphine oxide, arsine, isonitrile and isocyanate groups, in particular copolymers of styrene, of ethylene and their derivatives with butadiene, isoprene, cyclopentadiene, p-styryldiphenylphosphine and p-styryldiphenylphosphine oxide. The preparation of these metal clusters by thermal decomposition of carbonyl clusters of the metals in question is very complicated, which is why this process has not been able to become established.
Liu et al (Macromol. Symp. 105, 179 (1996)) describe the hydroformylation of propylene using rhodium clusters bound to polyvinylpyrrolidone which are colloidally dispersed in water. Since polyvinylpyrrolidone is not soluble in the hydroformylation medium, it is necessary when using this catalyst to carry out the reaction in a two-phase system of water/organic hydroformylation medium, as a result of which valuable high-pressure reaction space in the reactor is occupied by water, resulting in an unsatisfactory space-time yield based on the total reactor volume. In addition, these catalysts are very air-sensitive and are irreversibly deactivated if they come into contact with air during catalyst recycling.
Finally, U.S. Pat. No. 3,594,425 discloses a process for hydroformylation in which phosphorus-free, low molecular weight polyamines, including low molecular weight polyamines modified with alkylene oxides, are used as ligands. The specific poly- amines described all have a molecular weight of less than 300. Although it is indicated that the polyamine ligands open up the opportunity of recycling the catalyst complex with the distillation bottoms to the hydroformylation reaction, the use of the polyamines described there has
Decker Jurgen
Geissler Bernhard
Mahr Norbert
Paciello Rocco
Roper Michael
BASF - Aktiengesellschaft
Keil & Weinkauf
Padmanabhan Sreeni
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