Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
1998-08-04
2001-05-01
Stockton, Laura L. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S909000
Reexamination Certificate
active
06225507
ABSTRACT:
DESCRIPTION
The present invention relates to a process for the preparation of alcohols and/or aldehydes by the hydroformylation of olefins containing more than 3 carbon atoms, comprising the stage of hydroformylation using a rhodium catalyst homogeneously dissolved in the reaction medium, the separation of the rhodium catalyst from the effluent of the hydroformylation reaction by extraction with an aqueous solution of a water-soluble complexing polymer, isolation of the hydroformylation product from the organic phase, and precarbonylation of the aqueous extract containing the rhodium with the addition of an essentially water-immiscible organic liquid and recycling of the organic phase to the hydroformylation.
The hydroformylation of olefins with carbon monoxide and hydrogen in the presence of transition metal catalysts is well known. While &agr;-olefins are capable of hydroformylation to a high degree using rhodium-containing catalysts (cf J. Falbe, Ed.: New Syntheses With Carbon Monoxide, Springer, Berlin 1980, pp. 55 et seq), this catalyst system is less suitable for internal and internal, branched-chain olefins and also for olefins containing more than 7 carbon atoms (cf Falbe, pp. 95 et seq). Thus internal carbon—carbon double bonds are hydroformylated in the presence of such a catalyst only very slowly. Since the separation of the hydroformylation product from the homogeneous catalyst dissolved in the reaction system usually takes place by distillation and the boiling point of the aldehyde formed during hydroformylation increases with increasing carbon number and chain length to temperatures at which the rhodium-containing catalyst decomposes, this hydroformylation method is uneconomical for the hydroformylation of olefins containing more than 7 carbon atoms. In the hydroformylation of polymeric olefins such as polyisobutene, the noble metal-containing catalyst can not be recovered in a reusable form.
On the other hand internal and internal, branched-chain olefins can be advantageously hydroformylated with so-called “bare” rhodium, ie with homogeneous rhodium compounds dissolved in the hydroformylation medium and not modified with phosphorous ligands such as phosphines or phosphites. Such rhodium catalysts not modified with phosphines or phosphites and their suitability as catalysts for the hydroformylation of the aforementioned classes of olefins are known (cf Falbe, pp. 38 et seq). The terms “bare rhodium” or “bare rhodium catalysts” are used in this application for rhodium hydroformylation catalysts which are not modified, under the conditions of the hydroformylation, with ligands and particularly not with phosphorous ligands such as phosphine or phosphite ligands, unlike conventional rhodium hydroformylation catalysts. Carbonyl or hydrido ligands are not to be regarded as ligands in this context. It is assumed in the technical literature (cf Falbe, pp. 38 et seq), that the rhodium compound HRh(CO)
4
is the catalytically active rhodium species in the hydroformylation using “bare rhodium catalysts”, although this is not absolutely proven on account of the many chemisms concurrently taking place in the hydroformylation reaction zone. Only for the sake of simplicity do we also go by this assumption in the present application, without this imposing any restriction on the scope of the invention, if at some time in the future a rhodium species other than that stated should turn out to be the actual catalytically active species. The “bare rhodium catalysts” form under the conditions of the hydroformylation reaction from rhodium compounds, eg rhodium salts, such as rhodium(III) chloride, rhodium(III) nitrate, rhodium(III) acetate, rhodium(II) acetate, rhodium(III) sulfate, or rhodium(III) ammonium chloride, from rhodium chalkogenides, such as rhodium(III) oxide or rhodium(III) sulfide, from salts of rhodium oxyacids, for example the rhodates, from rhodium carbonyl compounds, such as Rh
4
(CO)
12
and Rh
6
(CO)
16
or from organorhodium compounds, such as rhodium dicarbonyl acetylacetonate, cyclooctadiene rhodium acetate or chloride in the presence of CO/H
2
mixtures, generally designated as synthesis gas. For information on the execution of hydroformylations with “bare” rhodium reference may be made, at this juncture, to the following literature by way of example: U.S. Pat. No. 4,400,547; DE-A 3338340; DE-A 2604545; WO 82/03856; Chem. Ber. 102, 2238 (1969); Tetrahedron Lett. 29, 3261 (1968); Hydrocarbon Process. 85-86(1975).
However hydroformylation using “bare” rhodium also suffers from the drawback that the thermolabile rhodium catalyst (cf U.S. Pat. No. 4,400,547) partially decomposes to metallic rhodium on account of the thermal load imposed during purification, by distillation, of the hydroformylation product, which is deposited on the walls of the reactor and pipes. The precipitated metallic rhodium cannot be recycled to the hydroformylation reaction, since it cannot be converted back to the catalytically active rhodium compound under the hydroformylation conditions. The loss of rhodium caused by this chemical behavior of “bare rhodium catalysts” have hitherto prevented any large-scale use of this process.
Numerous processes have been proposed in the literature to solve these problems, of which the process described in DE-A 4,230,871 (further prior literature also cited in said reference) is a useful solution in the form of the extraction of the catalyst using sulfonated, nitrogenous, low molecular weight chelating agents and recycling of the extracted catalyst. This process has been further improved in the process described in WO 95/25080. Said reference describes an additional precarbonylation of the extract prior to recycling to the hydroformylation.
A process similar to that disclosed in WO 95/250080 is described in EP-A 695,734, in which the catalyst is extracted from the hydroformylation effluent by means of an aqueous solution of a phosphorous chelating agent selected from the group consisting of monosulfonated or polysulfonated and/or carboxylated monophosphanes or oligophosphanes. All of the phosphorous chelating agents disclosed in EP-A 695,734 are low molecular weight compounds.
Whilst this improvement of the process in its industrial form has made it possible to operate it on an industrial scale, the success of the extraction itself has remained unsatisfactory: on the one hand the degree of extraction and also the reversibility of complex formation and dissociation in the precarbonylation has been unsatisfactory and on the other hand the sulfonic acid group-containing low molecular-weight chelating agents described in the above two specifications are not readily available and are expensive, so that the object of the invention is to find extracting agents which
are readily available
are water-soluble without migrating into the organic phase to any substantial extent, and
have strong complex-binding properties, so that good extracting efficiency is guaranteed.
According to the invention, this object has been achieved by means of a process for the preparation of aldehydes or aldehydes and alcohols by hydroformylation of olefins containing more than 3 carbon atoms, comprising a hydroformylation stage, in which the olefin is hydroformylated under a pressure of from 50 to 1000 bar and at a temperature of from 50° to 180° C. by means of a rhodium catalyst dissolved in a homogeneous reaction medium and a catalyst recovery stage comprising extraction of the rhodium catalyst with an aqueous solution of a chelating agent, isolation of alcohol and/or aldehyde from the extracted hydroformylation product stream, precarbonylation of the aqueous rhodium-containing extract in the presence of carbon monoxide, synthesis gas, or a gas mixture containing carbon monoxide under a pressure of from 50 to 1000 bar and at a temperature of from 50° to 180° C., separation of the effluent of the precarbonylation stage into an organic phase containing the major portion of the rhodium and an aqueous phase amended sheet containing the chelating agent and recycling of the organic phase to
Giessler Bernhard
Gunther Wolfgang
Kneuper Heinz-Josef
Oppenlander Knut
Paciello Rocco
BASF - Aktiengesellschaft
Keil & Weinkauf
Stockton Laura L.
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