GB2048239A

GB2048239A - Production of unsaturated carbonyl compounds

Info

Publication number: GB2048239A
Application number: GB7915118A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1979-05-01
Filing date: 1979-05-01
Publication date: 1980-12-10
Also published as: GB2048239B

Abstract

To produce an unsaturated carbonyl compound, a carbonyl compound is contacted with an aluminium oxycarbonate catalyst, the water formed by the reaction being removed as it is formed. Thus, for example, trimethylnonenone can be produced from methyl isobutyl ketone, mesityl oxide from acetone, cyclohexylidene cyclohexanone from cyclohexanone, and phenyl betamethylstyryl ketone from acetophenone.

Description

SPECIFICATION Production of unsaturated carbonyi compounds This invention relates to the use of an aluminium oxycarbonate catalyst in the production of unsaturated carbonyl compounds with simultaneous removal of water of reaction to maintain the catalytic activity of the oxycarbonate catalyst.

According to the invention, there is provided a process for producing an unsaturated carbonyl compound, which comprises subjecting a carbonyl compound to dehydration in the presence of an aluminium oxycarbonate catalyst, the water formed by the reaction being removed as it is formed.

The invention can be used, for example, in an aldol condensation and dehydration process for increasing the molecular weight of carbonyl compounds. The catalyst commonly used for such a process is sodium hydroxide. This process generally yields hydroxy carbonyl compounds which are often dehydrated to form unsaturated carbonyl compounds in the presence of an acid catalyst. For example, acetone is condensed in the presence of an alkaline compound to yield diacetone alcohol which is then dehydrated to yield mesityl oxide.

In accordance with the present invention, the aldol condensation and dehydration process can be carried out using an aluminium oxycarbonate catalyst in either a fixed or in a fluidised bed. Degradation of the aluminium oxycarbonate catalyst can be avoided, when the reaction is stopped, by the application of 002 to the catalyst.

As used herein, the term "aldol condensation" means a combined condensation-and-dehydration reaction utilizing carbonyl compounds (i.e. aldehydes and/or ketones), the term "fixed bed" means a stationary catalyst bed through which vapours and liquids move, and the term "fluidised bed" means a suspension of catalyst particles, the suspension being maintained by agitation.

The aldol condensation produces alpha-beta unsaturated carbonyl compounds. The aluminium oxycarbonate catalyst, maintained in either a fixed orfuidised bed, is also useful in the substitution of other carbonyl groups into such alpha-beta unsaturated carbonyl compounds. The substitution occurs at the alpha carbon of the unsaturated carbonyl compound. Water of reaction may be removed directly or it may be removed by reversal of the aldol condensation reaction.

The process of the present invention can be used to condense a wide variety of aldehydes and ketones. Carbonyl compounds containing from two to twenty carbon atoms are particularly desirable for condensation, but higher molecular weight carbonyl compounds can be used.

By the process of the present invention, it is now possible to condense higher molecular weight ketones.

if only one carbonyl compound is used in the aldol condensation process according to the present invention, it preferably has the following general formula:

wherein R1 and R2 are the same or different and each is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkaryl group or an aralkyl group, or Rl and R2 together form an alkylene group.

If two distinct aldehydes and/or ketones are used, at least one of them preferably has the general Formula (I).

The aluminium oxycarbonate catalyst can be prepared by heating aluminium hydroxide in a carbon dioxide atmosphere. The catalyst may also be prepared by heating Al203 in a CO2 atmosphere, or by treating aluminium oxide or hydroxide with CO2, while the aluminium compound is wetted with water or with a carbonyl compound. Other methods of combining aluminium with carbon dioxide will be apparent to those skilled in the art.

The catalytic activity of the aluminium compound improves rapidly with the initial addition of CO2 but soon reaches a very efficient state that improves little thereafter. The ratio of Al:CO2:0 can vary widely. Some CO2 is essential to ensure the catalytic activity of the catalyst.

The aluminium oxycarbonate catalyst may be used in various forms, for example as granules, pellets or powders. In the process of the invention, the catalyst is preferably maintained in a suitable reaction tube or chamber. The catalyst may be employed in a fixed bed over which the carbonyl compound in vapour and/or liquid form may be passed while carrying out the aldol condensation reaction. The catalyst may also be employed as a fluidised bed.

The temperature at which the aldol condensation reaction is carried out can be up to 2000C or higher. The preferred temperature range is between 800C and 1 50 C. The reaction speed decreases with temperature. At higher temperatures more undesired side reactions occur. The aldol condensation reaction should be conducted at a temperature at which the reactant and product remain stable. For example, aldehyde begins to decompose at about 2500.

The pressure at which the aldol condensation reaction is carried out may be, for example, from sub-atmospheric to about 50 atmospheres. The preferred pressure range is between 1 and 10 atmospheres. During the reaction, the carbonyl compound may be in the vapour phase and/or the liquid phase, but preferably it is a mixture of vapour and liquid with the vapour and liquid components of the mixture moving in opposite directions through the bed of the catalyst.

The preferred reaction conditions are such that the water of reaction is azeotropically removed from the catalyst chamber. Removal of water is essential to maintain the required catalytic activity of the catalyst. When using carbonyl compounds that readily form an azeotrope with water, it is convenient to operate at atmospheric pressure and at a temperature at or near the normal boiling point of the carbonyl compound. When using compounds such as acetone which do not readily form an azeotrope with water at such pressure and temperature, then the pressure and temperature may be raised. A solvent can be added to aid in the formation of an azeotrope and in separating the water.

Under the preferred reaction conditions, the hot vapours moving up through the catalyst bed contain the water of reaction, Upon condensation, the water separates from the organic condensate.

The organic condensate is refluxed through the catalyst thereby removing the reaction product.

Removal of the product from the catalyst bed is desirable to minimize formation of undesirable byproducts. Keeping the catalyst wetted with the liquid reactant also suppresses the formation of such byproducts.

When using a fluidised bed, it is preferred to remove the reaction mixture solution at reaction product concentrations of 75% or less, to limit the formation of such by-products.

In general, pressure of 1 to 10 atmospheres are preferred to establish the boiling points of the carbonyl compounds in the desired 800C to 1 500C temperature operating range.

In the presence of the aluminium oxycarbonate catalyst, the aldol condensation dehydration process is reversible, which is an important advantage of the invention. Due to this reversibility of the aldol condensation process, it is now possible to produce additional unsaturated carbonyl compounds by contacting the aluminium oxycarbonate catalyst with alpha-beta unsaturated carbonyl compounds, either alone or in the presence of another carbonyl compound. The reaction conditions previously described can be used to produce these additional compounds but temperatures below 800C can also be used.

The present invention will be illustrated by the following Examples.

EXAMPLE 1 There was used an aldol condensation dehydration pilot plant consisting of (1) an autoclave fitted with heating steam coils, (2) a 1 5 cm diameter vertical tube having a "catalyst chamber" extending above the autoclave, sections to this tube above and below the catalyst chamber being packed with ceramic saddles, (3) a condenser, and (4) a condensate receiver.

Methyl isobutyl ketone (MIBK) was refluxed in the autoclave at atmospheric pressure. The 2,6,8trimethyl-5-nonen-4-one (TMNO) formed was removed from the bottom of the autoclave. The catalyst chamber was packed with the aluminium oxycarbonate catalyst.

The water by-product from the reaction was removed from the receiver while the MIBK from the receiver was returned to the top of the vertical tube as reflux.

The operating conditions were as given in the following Table 1: Table 1

Catalyst Depth Run Time TMNO Conversion TMNO Rate (cm) (Hours) (kg) (gm/cm2/hr*) (%) 24 11 9 4.4 100 81 260 977 20 98 208 80.5 536 36 96.6 305 - - 46 * Gram/cm 2of cross sectional area of the catalyst chamber.

EXAMPLE 2 The plant described in Example 1 was used. Acetone was refluxed through the catalyst bed while mesityl oxide was removed from the autoclave. Normal pentane was refluxed to the top of the tube to aid in the removal of water from the refluxing acetone. Water was removed from the receiver.

The operating conditions were as given in the following Table 2:

Catalyst Depth Pressure Conversion Rate (cm) (Atmospheres) (gm/cm2/hr) 142 3 3.7-5.4 142 3.7 4.4-7.3 142 4.4 6.3 142 5.1 7.8 - 9.3 142 5.8 11 142 6.4 14.6 - 16 305 7.8 49 EXAMPLE 3 There was used a plant as described in Example 1 with a catalyst depth of 305 cm. The plant was pressurised overnight with CO2 at 3.7 atmospheres.This CO2 treatment enhanced the catalytic activity of the aluminium oxycarbonate and the conversion rate to TMNO increased to more than 50 gm/cm2/hr.

EXAMPLE 4 A three litre flask equipped with a stirrer to produce a fluidised bed was used. A receiver and condenser extended upward from the flask. To the flask, 1 kg of MIBK and 100 gm of aluminium oxycarbonate (fine powder) were added, and heated to an initial boiling point of 11 50C. The MIBK and water formed an azeotrope, and 67 ml of MIBK saturated with water was removed. Thereafter, MIBK was continually refluxed to the flask. Over a ten hour period, the temperature of the flask increased from 1 550C to 1450 C, and 760 gm of product were removed from the reaction flask. Distillation produced 250 gm of MIBK and 410 gm of TMNO. Remaining from the distillation was 100 gm of residue. The conversion of MIBK was 70%. The reaction product was 80.4% TMNO.

This Example illustrates that the aluminium oxycarbonate catalyst can be utilized in a fluidised bed as well as in a fixed bed.

EXAMPLE 5 A three litre flask was used to carry out an aldol condensation process. Extending from the flask was a 50 mm diameter column. The column was packed at the bottom with ceramic saddles. The centre 25 cm section of the column was packed with aluminium oxycarbonate. The top 1 2 cm section of the column was packed with ceramic or porcelain saddles. A receiver and a water-cooled condenser were operatively coupled to the top section of the column.

The flask was charged with 1,800 ml of methyl ethyl ketone (MEK) and refluxed at atmospheric pressure. A small amount of n-hexane, added to the condenser, aided in the water separation. After refluxing for 1 3 hours, approximately 70% of the original MEK was condensed to a product having a distinct spicy odor. The condensation products were 5-methyl-4-hepten-3-one and 3,4-dimethyl-3hexen-2-one.

EXAMPLE 6 The same equipment as described in Example 5 was used. The flask was charged with 1,600 ml of n-butanal and 200 ml of n-hexane. Refluxing at atmospheric pressure, the n-butanal was condensed to 2-ethylhexanal at a rate of approximately 20 gm/hr.

EXAMPLE 7 The same equipment as described in Example 5 was used. The flask was charged with 2,500 ml of mesityl oxide. Refluxing at atmospheric pressure resulted in a mixture of C9 di-unsaturated ketones. The conversion rate was approximately 300 gm/hr. Removal of water was accomplished by reversal of the aldol condensation reaction to form acetone. The acetone was removed from the reaction while it was being formed.

EXAMPLE 8 The equipment of Example 1 was used. The catalyst had depth of 24 cm. It was allowed to stand overnight. The reaction was restarted the next day. The rate of formation of TMNO was slightly greater than 3.9 gm/cm2/hr. After standing again overnight, the rate of TMNO formation was less than that amount. Loss of activity of the catalyst continued with subsequent stops and starts. To prevent such degradation of the catalyst, CO2 treatment of the catalyst at each shutdown was used. After such CO2 treatment, no apparent loss of catalytic activity reoccurred.

EXAMPLE 9 TMNO was heated in the presence of aluminium oxycarbonbate using the same equipment as described in Example 4. The resulting products were decanted and distilled. The distillate consisted of MIBK, unreacted TMNO, CO,8 di-unsaturated ketones, and distillation residues.

EXAMPLE 10 Using the equipment as described in Example 4, 1 500 ml of cyclohexanone and 100 gm of aluminium oxycarbonate were added to the flask, and heated to an initial boiling point of 1 420C. Water evolved quickly and the temperature of the flask rose to 200or in three hours. The liquid was decanted, and distilled to yield unreacted cyclohexanone, cyclohexylidene cyclohexanone, and a higher molecular weight condensation product, C18H26O, believed to be di-cyclohexylidene cyclohexanone.

EXAMPLE 11 Using the equipment as described in Example 5, 1 500 ml of cyclohexanone were added to the flask, and heated to boiling. After seven hours the temperature of the flask was 21 00C. Distillation yielded about 80% cyclohexylidene cyclohexanone together with unreacted cyclohexanone. Very little of the higher molecular weight condensation products were produced.

EXAMPLE 12 Using the equipment as described in Example 4, 1 700 ml of acetophenone were added along with 300 gm of the catalyst. Also added, as a solvent, were 100 ml of hexane to suppress the boiling point and ta form an azeotrope with the water. The aldol condensation was rapid. The yield was 65% phenyl beta-methylstytyl ketone.

As will be apparent to those skilled in the art, the invention provides a process which can be very efficient and economical. Simplicity of the process and the required equipment make it possible to utilize small and, therefore, relatively inexpensive production plants. Accordingly, these smaller plants can be more advantageously located near the source of materials or markets. In addition, the process of the invention can produce products for which no previously known process was commercially suitable.

Claims

1. A process for producing an unsaturated carbonyl compound, which comprises subjecting a carbonyl compound to dehydration in the presence of an aluminium oxycarbonate catalyst, the water formed by the reaction being removed as it is formed.

2. A process according to claim 1, wherein the carbonyl compound also undergoes condensation with itself or with another carbonyl compound.

3. A process according to claim 2, wherein the or at least one of the carbonyl compounds has the general formula:

wherein R1 and R2 are the same or different and each is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkaryl group or an aralkyl group, or R and R2 together form an alkylene group.

4. A process according to claim 3, wherein the carbonyl compound used is methyl isobutyl ketone and the unsaturated carbonyl compound produced is trimethyinonenone.

5. A process according to claim 3, wherein the carbonyl compound used is acetone and the unsaturated carbonyl compound produced is mesityl oxide.

6. A process according to claim 3, wherein the carbonyl compound used is cyclohexanone and the unsaturated carbonyl compound produced is cyclohexylidene cyclohexanone.

7. A process according to claim 3, wherein the carbonyl compound used is acetophenone and the unsaturated carbonyl compound produced is phenyl beta-methylstyryl ketone.

8. A process according to claim 2 or 3, wherein the carbonyl compound used is an alpha-beta unsaturated compound, and wherein this compound undergoes condensation either with itself or with another carbonyl compound.

9. A process according to claim 8, wherein mesityl oxide undergoes condensation to produce a C9- diunsaturated ketone.

10. A process according to any of claims 2 to 9, wherein condensation is curried out in the presence of a solvent to aid in the removal of water.

11. A process according to any of claims 1 to 10 wherein the catalyst is in the form of a fixed bed or a fluidised bed.

1 2. A process according' to any of claims 1 to 1 wherein the process is effected at a temperature of from 80 to 1500C.

1 3. A process according to any of claims 1 to 12, wherein the activity of the catalyst is maintained and/or enhanced by treating it with CO2.

14. An unsaturated carbonyl compound, when produced by a process according to any of claims 1 to 13.

14. A process for producing an unsaturated carbonyl compound, substantially as described in any of the foregoing Examples.

1 5. An unsaturated carbonyl compound, when produced by a process according to any of claims 1 to 14.

New claims ammendments to claims filed on 13 June 1 980 Superseded claims all New or amended claims:

1. A process for producing an unsaturated carbonyl compound, which comprises contacting at least one ketone or aldehyde with an aluminium oxycarbonate catalyst, the water formed by the reaction being removed as it is formed.

2. A process according to claim 1, wherein the ketone or aldehyde or at least one of the ketones or aldehydes has the general formula:

wherein R1 and R2 are the same or different and each is a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkaryl group or an aralkyl group, or R1 and R2 together form an alkylene group.

3. A process according to claim 2, wherein methyl isobutyl ketone is contacted with the catalyst to produce trimethylnonenone.

4. A process according to claim 2, wherein acetone is contacted with the catalyst to produce mesityl oxide.

5. A process according to claim 2, wherein cyclohexanone is contacted with the catalyst to produce cyclohexylidene cyclohexanone.

6. A process according to claim 2, wherein acetophenone is contacted with the catalyst to produce phenyl beta-methylstyryl ketone.

7. A process according to claim 2, wherein an alpha-beta unsaturated ketone or aldehyde, or a mixture thereof with a different ketone or aldehyde, is contacted with the catalyst.

8. A process according to claim 7, wherein mesityl oxide is contacted with the catalyst to produce a C9-diunsaturated ketone.

9. A process according to any of claims 1 to 8, wherein the reaction is carried out in the presence of a solvent to aid in the removal of water.

1 0. A process according to any of claims 1 to 9, wherein the catalyst is in the form of a fixed bed or a fluidised bed.

1 A process according to any of claims 1 to 10, wherein the process is effected at a temperature of from 80 to 1 500C.

1 2. A process according to any of claims 1 to 1 wherein the activity of the catalyst is maintained and/or enhanced by treating it with CO2.

1 3. A process for producing an unsaturated carbonyl compound, substantially as described in any of the foregoing Example.