Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-10-17
2003-04-08
Richter, Johann (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S343000, C568S346000, C568S354000
Reexamination Certificate
active
06545185
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to the preparation of ketones. More particularly, this invention relates to a method and apparatus for preparing ketones via catalytic reaction from an aldehyde and a carboxylic acid.
BACKGROUND OF THE INVENTION
In general, unsymmetrical ketones are useful as intermediates for the production of numerous specialty chemicals. More specifically, methyl cyclopropyl ketone (MCPK) has a variety of current and potential uses including, among others, the production of specialty agricultural and pharmaceutical compounds.
Numerous literature references cite and disclose various well-known processes for the preparation of ketones. These processes include oxidation of secondary alcohols, Friedel-Crafts acylation, reaction of acid chlorides with organo cadmium compounds, acetoacetic ester synthesis and decarboxylation from acids, among others.
Text and literature references also detail problems associated with using these processes to produce ketones. These include problems such as the unavailability and/or cost of raw materials, the requirement of multi-stage processing, the low conversion of the raw materials and/or the low selectivity of the desired ketones, and the production of corrosive or hard to separate products.
Ketone production processes have also been described in the patent literature. For example, U.S. Pat. Nos. 4,528,400 and 4,570,021 disclose a process for the preparation of unsymmetrical ketones by a catalytic vapor phase reaction using reactants such as ketones with carboxylic acids. However, laboratory trials using acetone and cyclopropanecarboxylic acid resulted in the production of high quantities of gamma-butyrolactone, several pentenones and pentanones, but no MCPK.
U.S. Pat. Nos. 3,410,909 and 3,453,331 disclose processes for the preparation of symmetrical and unsymmetrical ketones from aldehydes containing up to 8 carbons in a non-cyclic saturated aliphatic chain.
German Patent Disclosure No. P36 37 788.0 (1986) discloses a specific condensation reactor process for the preparation of methyl cyclopropyl ketone (MCPK) from cyclopropanecarboxylic acid or its derivatives. However, although examples from this patent show raw material conversion of from 58 to 99 percent and selectivity to MCPK of 42 to 75 percent, the liquid hourly space velocity (LHSV) or weight hourly space velocity (WHSV) values of less than 1 (i.e., 0.25 to 0.99) minimize the industrial usefulness of this condensation reactor process.
European Patent Application No. 0 085 996 also discloses processes for the preparation of unsymmetric aliphatic ketones at atmospheric pressures (or slightly above) and at relatively low WHSV.
U.S. Pat. No. 3,966,822 (Fukui et al.) discloses the preparation of ketones from aldehydes in the presence of zirconium oxide and various other catalysts. U.S. Pat. No. 3,466,334 (Young et al.) discloses synthesis of ketones from an aldehyde and an acid in the presence of a catalyst comprised of an alumina-supported oxidized form of lithium. U.S. Pat. No. 3,453,331 (Hargis et al.) discloses a process for the synthesis of ketones from aldehydes using various alumina-supported oxidized forms of various metals. WO 00/30448, published Jun. 2, 2000 and entitled “Method and Apparatus for the Preparation of Ketones”, describes methods for the catalyst-mediated production of ketones. In general, an acid or aldehyde or derivatives thereof and a carboxylic acid are reacted in the presence of a catalyst to produce a desired ketone.
The most common industrial processes for the production of ketones typically involve the reaction of an acid in the presence of a catalyst. Catalyzed reactions such as these can be low in yield due to side reactions and/or the reactant throughput can be low due to system requirements.
Thus, there is a need in the art for a method to produce ketones in high yields in a cost-effective manner.
SUMMARY OF THE INVENTION
The present invention relates to a method and an apparatus for producing ketones via a one step synthesis from aldehydes. This synthesis has good selectivity and conversion rates. Particularly desirable reaction products include asymmetrical ketones such as methyl cyclopropyl ketone (MCPK). The method and apparatus of the present invention utilizes readily available and relatively inexpensive raw materials and results in high conversion and selectivity rates.
Generally, the raw materials used in this invention include an aldehyde, a carboxylic acid, and a source of oxygen, such as water.
In a preferred embodiment, this invention involves the reaction of cyclopropanecarboxaldehyde, acetic acid, and water at elevated temperatures in the presence of a catalyst to form methyl cyclopropyl ketone (MCPK). Vaporized reactants flow through a tube reactor provided with a suitable catalyst.
In one aspect, this invention is a method for the production of a ketone comprising providing a tube reactor having a catalytic bed; providing a carboxylic acid, a source of oxygen; and an aldehyde, and passing the carboxylic acid, the source of oxygen, and the aldehyde, each in a vapor phase, through the catalytic bed at a weight hourly space velocity greater than 1 to form the ketone. The ketone may be an asymmetrical ketone and the carboxylic acid and the aldehyde may be heated before entering the tube reactor. Preferably, the weight hourly space velocity is in the range of 1 to 20. In a preferred embodiment, the weight hourly space velocity is in the range of 2 to 20. In another preferred embodiment, the weight hourly space velocity is in the range of 5 to 20. The reacting may take place in two or more tube reactors connected in parallel. Preferably, the catalyst is a theoretical monolayer on a solid support. The method may also include the step of recovering the ketone. In preferred embodiments, the source of oxygen is water. In another preferred embodiment, the ketone is methyl cyclopropyl ketone, the aldehyde is cyclopropanecarboxaldehyde, and the acid is acetic acid. The weight ratio of the carboxylic acid: source of oxygen: aldehyde may range from 1:1:1 to 20:1:1. The catalyst may be selected from MgO, TiO
2
, ZrO
2
, ZnO, CeO
2
, and Ce
2
O
3
. A preferred catalyst is CeO
2
on a TiO
2
support wherein there is about 15 to 20% CeO
2
per gram of TiO
2
. The method may be a continuous process.
In a second aspect, this invention is a method of preparing a ketone comprising providing a plurality of tube reactors, each having a catalytic bed; providing a raw material feed comprised of a carboxylic acid, a source of oxygen, and an aldehyde, to produce the ketone; selectively passing the raw material feed through the catalytic bed of at least one of the plurality of tube reactors at a temperature of between about 350° C. and 500° C. and a weight hourly space velocity of greater than 1; and recovering the ketone. This method may also include selectively stopping the passage of raw material feed through the catalytic bed of the at least one tube reactor and passing the raw material feed through the catalytic bed of at least one of the plurality of tube reactors, and/or regenerating the catalytic bed of the at least one tube reactor through which the passage of raw material feed has been stopped. Preferably, the catalytic bed includes a CeO
2
/TiO
2
catalyst structure having about 15 to 20% CeO
2
per gram of TiO
2
.
In a third aspect, this invention is a process for the production of a ketone comprising reacting acetic acid with cyclopropanecarboxaldehyde and with water to form methyl cyclopropyl ketone; wherein the reacting occurs in the vapor phase and in the presence of a catalyst.
In a fourth aspect, this invention is a process for the preparation of a compound of formula (I)
wherein:
R
1
is cycloalkyl having from three to six ring carbon atoms which is unsubstituted or which has one or more substituents selected from the group consisting of R
4
and halogen; R
2
is halogen; straight- or branched-chain alkyl having up to six carbon atoms which is substituted by one or more —OR
5
; cycloalkyl having from
Warren Jack S.
Westphal David R.
Zoubek Steve J.
EagleView Technologies, Inc.
Popovich & Wiles, P.A.
Richter Johann
Witherspoon Sikarl A.
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