CA1047528A - Catalytic decomposition of an aldehyde to acetic acid and methacrolein - Google Patents
Catalytic decomposition of an aldehyde to acetic acid and methacroleinInfo
- Publication number
- CA1047528A CA1047528A CA209,313A CA209313A CA1047528A CA 1047528 A CA1047528 A CA 1047528A CA 209313 A CA209313 A CA 209313A CA 1047528 A CA1047528 A CA 1047528A
- Authority
- CA
- Canada
- Prior art keywords
- methacrolein
- methyl
- acetic acid
- catalyst
- acetoxypropionaldehyde
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Abstract
ABSTRACT OF THE DISCLOSURE
A process for separating 2-methyl-3-acetoxypropion-aldehyde from an isomeric mixture of aldehydes by catalytic decomposition.
A process for separating 2-methyl-3-acetoxypropion-aldehyde from an isomeric mixture of aldehydes by catalytic decomposition.
Description
~ 75~8 ~3CH 1892 It is known in the art that an ester when heated at: 300-550C. decomposes into an olefin and a carboxylic acid.
The reaction may be carried out in either the liquid or the vapor phase, by simply heating the ester in a metal bath or with a free flame or by passing the compound through an elec-trically heated tube.
Also, it is known that dehydration of ~ -hydroxy-aldehydes is a facile reaction catalyzed by many materials such as acids, bases, alumina, etc. Separation of a particular acetoxyaldehyds from an isomeric mixture of acetoxyaldehydes is difficult since the catalyst in many instances will react with the acetoxyaldehydes. However, it has been discovered that a particular acetoxyaldehyde may be decomposed by an elimination catalyst without reaeting with the other acetoxyaldehydes.
This invention is concerned with a process for separating 2-methyl-3-acetoxypropionaldehyde from an isomeric mixture of 4-acetoxybutyraldehyde, 2-methyl-3-acetoxypropion-aldehyde and 2-acetoxybutyraldehyde which comprises heating said isomeric mixture in the presence of an elimination catalyst which decompoSes the 2-methyl-3-acetoxypropionaldehyde to acetic acid and methacrolein and separating the acetic acid and methacrolein therefrom, said elimination catalyst being selected from the group consisting of a tertiary amine, silica-aluminas and zeolites.
The isomeric aldehydes of the present invention are produced by the hydroformylation of allyl acetate which is disclosed in a Canadian application of William E. Smith, entitled A Process for the Production of Butanediol, Serial No. 203,212, filed June 24, 1974 and assigned to the same assignee as the present invention. Also, this application of Smith discloses hydrogenating these aldehydes to produce a mixture comprising the acetate esters of the corresponding butanediols. This .
._ 1 ~
10~ 75~ 8CH-1892 mixture of the acetate esters of butanediols is then de-esterified to produce a mixture of diols. 1,4-butanediol is useful in making polyester resins with dicarboxylic acids.
The 2-methyl-3-acetoxypropionaldehyde of the instant invention has a boiling point which lies between the boiling points of 4-acetoxybutyraldehyde and 2-acetoxybutyr-aldehyde. This makes separation of an isomeric mixture of 4-acetoxybutyraldehyde, 2-methyl-3-acetoxyproprionaldehyde and 2-acetoxybutyraldehyde difficult. Also, this makes difficult the separation of the isomeric diols which are produced from hydrogenation of the isomeric aldehydes followed by de-esterification, since a diol corresponding to 2-methyl-3-acetoxyproprionaldehyde would be formed which has a boiling point between the diol corresponding to 2-acetoxybutyraldehyde and the diol corresponding to 4-acetoxybutyraldehyde. The two products, i.e., acetic acid and methacrolein, obtained by decomposing 2-methyl-3-acetoxypropionaldehyde, have a high volatility and are easily removed by distillation from the mixture of 4-acetoxybutyraldehyde, 2-acetoxybutyraldehyde, acetic acid and methacrolein.
Also, this invention is concerned with a process for separating 2-methyl-3-acetoxypropionaldehyde from an isomeric mixture of 4-acetoxybutyraldehyde, 2-methyl-3-acetoxypropionaldehyde and 2-acetoxybutyraldehyde by heating said mixture in the presence of an elimination catalyst which decomposes the 2-met~yl-3-acetoxypropionaldehyde to acetic acid and methacrolein without reacting with either the 4-acetoxybutyraldehyde or the 2-acetoxybutyraldehyde.
This elimination catalyst which may be employed within the scope of this invention is selected from the group consisting of a tertiary amine, silica-aluminas and zeolites.
The tertiary amines which may be used include alkylamines, ~475~ 8CH-1892 arylamines, cycloalkylamines, alkarylamines and aralkylamines of 1 to 25 carbon atoms as well as heterocyclic amines.
Examples of tertiary amines which may be used include tri-methylamine, triethylamines, tri-n-propylamine, tri-n-butylamine, tri-n-amylamine, tribenzylamine, propyldimethyl-amine, methyldiethylamine, butyldimethylamine, t-butyldimethyl-amine, pentyldimethylamine, methylethylbutylamine, heptyldi-methylamine, nonyldimethylamine, tetradecyldimethylamine, tri-cyclohexylamine, triphenylamine, pydridine, etc.
The silica-aluminas which may be used vary in com-position from pure silica to pure alumina.
The zeolites of the instant invention include both the natural zeolites and the alkali metal aluminosilicates or the commercial zeolites, also known as molecular sieves.
These zeolites are well known in the art and are detailed in Molecular Sieves, Charles K. Hersh, Reinhold Publishing Company, New York (1961). Preferably, representative natural zeolites which may be employed in the instant invention include those in Table 3-1, on page 21 of the Hersh reference while representative molecular sieves include those in Table 5-1, on page 54 of the Hersh reference. A most preferred molecular sieve is a Davison Molecular Sieve Type 3A which has a silica-alumina base with potassium as the cation.
The catalyst may be added along with the isomeric aldehydes into a reaction zone. A preferred amount of catalyst is about from 0.5% to about 2% based on weight of the isomeric aldehydes. If the catalyst is a molecular sieve or silica-aluminas, t~e reactants are flowed through the molecular sieve or silica-alumina in a reaction zone.
The temperature at which the reaction proceeds can be varied widely. Temperatures ranging from about 90 to 180C.
i()475~ 8CH-1892 are generally adequate although higher temperatures can be used.
Although atmospheric pressures are the only ones normally required, it will be of course apparent to those skilled in the art that superatmospheric pressure or sub-atmospheric pressure may be used where conditions and con-centrations so dictate.
The following Examples are set forth to illustrate more clearly the principle and practice of this invention to those skilled in the art. Unless otherwise specified, where parts or percents are mentioned, they are parts or percents by weight.
ExamPle I - 0.3 g. of triethylamine is added to an 18.0 g. mixture containing (by weight) 4-acetoxybutanaldehyde (69%), 2-acetoxybutanaldehyde (10%) and 2-methyl-3-acetoxy-propionaldehyde (15%), (the mixture of aldehyde isomers ob-tained from the hydroformylation reaction of allyl acetate).
The mixture is heated at 95C. in a flask equipped with a reflux condenser. Analysis shows that within 25 minutes 2-methyl-3-acetoxypropionaldehyde is completely converted into methacrolein and acetic acid. The other two aldehyde isomers remained unchanged. Methacrolein and acetic acid are separated from the aldehyde isomers by distillation.
Example II - 1.0 g. of activated alumina 1/8" pellets is added to a 10.0 g. mixture containing (by weight) 4-acetoxy-butanaldehyde (69%), 2-acetoxybutanaldehyde (10%) and 2-methyl-3-acetoxypropionaldehyde (15%). The mixture is heated at 125 C.
in a flask equipped with a reflux condenser. Analysis shows that within 20 minutes 2-methyl-3-acetoxypropionaldehyde is completely converted into methacrolein and acetic acid. The other two aldehyde isomers remain unchanged. Methacrolein and acetic acid are separated from the aldehyde isomers by distillation.
~47528 8CH-1892 Example III - A jacketed stainless steel column 127 cm. long and 1.9 cm. in diameter is packed with a zeolite molecular sieve. The column is heated to 150C. and a mixture containing (by weight) 4-acetoxybutanaldehyde (57%1, 2-acetoxybutanaldehyde (8%), 2-methyl-3-acetoxypropionaldehyde (13%) and water (16%) is pumped through the column at a rate of 7 ml./minute. Approximately 22 liters are passed through the column. Analysis shows that, in the product stream,
The reaction may be carried out in either the liquid or the vapor phase, by simply heating the ester in a metal bath or with a free flame or by passing the compound through an elec-trically heated tube.
Also, it is known that dehydration of ~ -hydroxy-aldehydes is a facile reaction catalyzed by many materials such as acids, bases, alumina, etc. Separation of a particular acetoxyaldehyds from an isomeric mixture of acetoxyaldehydes is difficult since the catalyst in many instances will react with the acetoxyaldehydes. However, it has been discovered that a particular acetoxyaldehyde may be decomposed by an elimination catalyst without reaeting with the other acetoxyaldehydes.
This invention is concerned with a process for separating 2-methyl-3-acetoxypropionaldehyde from an isomeric mixture of 4-acetoxybutyraldehyde, 2-methyl-3-acetoxypropion-aldehyde and 2-acetoxybutyraldehyde which comprises heating said isomeric mixture in the presence of an elimination catalyst which decompoSes the 2-methyl-3-acetoxypropionaldehyde to acetic acid and methacrolein and separating the acetic acid and methacrolein therefrom, said elimination catalyst being selected from the group consisting of a tertiary amine, silica-aluminas and zeolites.
The isomeric aldehydes of the present invention are produced by the hydroformylation of allyl acetate which is disclosed in a Canadian application of William E. Smith, entitled A Process for the Production of Butanediol, Serial No. 203,212, filed June 24, 1974 and assigned to the same assignee as the present invention. Also, this application of Smith discloses hydrogenating these aldehydes to produce a mixture comprising the acetate esters of the corresponding butanediols. This .
._ 1 ~
10~ 75~ 8CH-1892 mixture of the acetate esters of butanediols is then de-esterified to produce a mixture of diols. 1,4-butanediol is useful in making polyester resins with dicarboxylic acids.
The 2-methyl-3-acetoxypropionaldehyde of the instant invention has a boiling point which lies between the boiling points of 4-acetoxybutyraldehyde and 2-acetoxybutyr-aldehyde. This makes separation of an isomeric mixture of 4-acetoxybutyraldehyde, 2-methyl-3-acetoxyproprionaldehyde and 2-acetoxybutyraldehyde difficult. Also, this makes difficult the separation of the isomeric diols which are produced from hydrogenation of the isomeric aldehydes followed by de-esterification, since a diol corresponding to 2-methyl-3-acetoxyproprionaldehyde would be formed which has a boiling point between the diol corresponding to 2-acetoxybutyraldehyde and the diol corresponding to 4-acetoxybutyraldehyde. The two products, i.e., acetic acid and methacrolein, obtained by decomposing 2-methyl-3-acetoxypropionaldehyde, have a high volatility and are easily removed by distillation from the mixture of 4-acetoxybutyraldehyde, 2-acetoxybutyraldehyde, acetic acid and methacrolein.
Also, this invention is concerned with a process for separating 2-methyl-3-acetoxypropionaldehyde from an isomeric mixture of 4-acetoxybutyraldehyde, 2-methyl-3-acetoxypropionaldehyde and 2-acetoxybutyraldehyde by heating said mixture in the presence of an elimination catalyst which decomposes the 2-met~yl-3-acetoxypropionaldehyde to acetic acid and methacrolein without reacting with either the 4-acetoxybutyraldehyde or the 2-acetoxybutyraldehyde.
This elimination catalyst which may be employed within the scope of this invention is selected from the group consisting of a tertiary amine, silica-aluminas and zeolites.
The tertiary amines which may be used include alkylamines, ~475~ 8CH-1892 arylamines, cycloalkylamines, alkarylamines and aralkylamines of 1 to 25 carbon atoms as well as heterocyclic amines.
Examples of tertiary amines which may be used include tri-methylamine, triethylamines, tri-n-propylamine, tri-n-butylamine, tri-n-amylamine, tribenzylamine, propyldimethyl-amine, methyldiethylamine, butyldimethylamine, t-butyldimethyl-amine, pentyldimethylamine, methylethylbutylamine, heptyldi-methylamine, nonyldimethylamine, tetradecyldimethylamine, tri-cyclohexylamine, triphenylamine, pydridine, etc.
The silica-aluminas which may be used vary in com-position from pure silica to pure alumina.
The zeolites of the instant invention include both the natural zeolites and the alkali metal aluminosilicates or the commercial zeolites, also known as molecular sieves.
These zeolites are well known in the art and are detailed in Molecular Sieves, Charles K. Hersh, Reinhold Publishing Company, New York (1961). Preferably, representative natural zeolites which may be employed in the instant invention include those in Table 3-1, on page 21 of the Hersh reference while representative molecular sieves include those in Table 5-1, on page 54 of the Hersh reference. A most preferred molecular sieve is a Davison Molecular Sieve Type 3A which has a silica-alumina base with potassium as the cation.
The catalyst may be added along with the isomeric aldehydes into a reaction zone. A preferred amount of catalyst is about from 0.5% to about 2% based on weight of the isomeric aldehydes. If the catalyst is a molecular sieve or silica-aluminas, t~e reactants are flowed through the molecular sieve or silica-alumina in a reaction zone.
The temperature at which the reaction proceeds can be varied widely. Temperatures ranging from about 90 to 180C.
i()475~ 8CH-1892 are generally adequate although higher temperatures can be used.
Although atmospheric pressures are the only ones normally required, it will be of course apparent to those skilled in the art that superatmospheric pressure or sub-atmospheric pressure may be used where conditions and con-centrations so dictate.
The following Examples are set forth to illustrate more clearly the principle and practice of this invention to those skilled in the art. Unless otherwise specified, where parts or percents are mentioned, they are parts or percents by weight.
ExamPle I - 0.3 g. of triethylamine is added to an 18.0 g. mixture containing (by weight) 4-acetoxybutanaldehyde (69%), 2-acetoxybutanaldehyde (10%) and 2-methyl-3-acetoxy-propionaldehyde (15%), (the mixture of aldehyde isomers ob-tained from the hydroformylation reaction of allyl acetate).
The mixture is heated at 95C. in a flask equipped with a reflux condenser. Analysis shows that within 25 minutes 2-methyl-3-acetoxypropionaldehyde is completely converted into methacrolein and acetic acid. The other two aldehyde isomers remained unchanged. Methacrolein and acetic acid are separated from the aldehyde isomers by distillation.
Example II - 1.0 g. of activated alumina 1/8" pellets is added to a 10.0 g. mixture containing (by weight) 4-acetoxy-butanaldehyde (69%), 2-acetoxybutanaldehyde (10%) and 2-methyl-3-acetoxypropionaldehyde (15%). The mixture is heated at 125 C.
in a flask equipped with a reflux condenser. Analysis shows that within 20 minutes 2-methyl-3-acetoxypropionaldehyde is completely converted into methacrolein and acetic acid. The other two aldehyde isomers remain unchanged. Methacrolein and acetic acid are separated from the aldehyde isomers by distillation.
~47528 8CH-1892 Example III - A jacketed stainless steel column 127 cm. long and 1.9 cm. in diameter is packed with a zeolite molecular sieve. The column is heated to 150C. and a mixture containing (by weight) 4-acetoxybutanaldehyde (57%1, 2-acetoxybutanaldehyde (8%), 2-methyl-3-acetoxypropionaldehyde (13%) and water (16%) is pumped through the column at a rate of 7 ml./minute. Approximately 22 liters are passed through the column. Analysis shows that, in the product stream,
2-methyl-3-acetoxypropionaldehyde is completely converted into methacrolein and acetic acid and the other two aldehyde isomers remain unchanged. Methacrolein and acetic acid are separat~dfrom the aldehyde isomers by distillation.
It should, of course, be apparent to those skilled in the art that changes may be made in the particular embodiments of the invention described which are within the full intended scope of the invention as defined by the appended claims.
It should, of course, be apparent to those skilled in the art that changes may be made in the particular embodiments of the invention described which are within the full intended scope of the invention as defined by the appended claims.
Claims (9)
1. A process for separating 2-methyl-3-acetoxy-propionaldehyde from an isomeric mixture of 4-acetoxybutyral-dehyde, 2-methyl-3-acetoxypropionaldehyde and 2-acetoxy-butyraldehyde which comprises heating at a temperature of from about 90°C to about 180°C said mixture in the presence of an elimination catalyst which decomposes in 2-methyl-3-acetoxypropionaldehyde to acetic acid and methacrolein, and separating the acetic acid and methacrolein therefrom; said elimination catalyst being selected from the group consisting of a tertiary amine, silica-aluminas and zeolites.
2. The process of claim 1 wherein said tertiary amine is selected from the group consisting of alkylamines, cycloalkylamines, alkarylamines, aralkylamines and heterocyclic amines.
3. The process of claim 2 wherein said silica-aluminas have a composition which may vary from pure silica to pure alumina.
4. The process of claim 1 wherein said zeolite is a synthetic alkali metal alumina silicate.
5. The process of claim 4 wherein said alkali metal is potassium.
6. The process of claim 3, 4 or 5 wherein the reac-tants are flowed through the catalyst in a reaction zone.
7. The process of claim 2 wherein said catalyst is present in an amount of about 0.5% to about 2% by weight based on the weight of said isomeric aldehydes.
8. The process of claim 1, 2 or 7 wherein the tertiary amine is pyridine.
9. The process of claim 1, 2 or 7 wherein the tertiary amine is triethylamine.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA209,313A CA1047528A (en) | 1974-09-16 | 1974-09-16 | Catalytic decomposition of an aldehyde to acetic acid and methacrolein |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA209,313A CA1047528A (en) | 1974-09-16 | 1974-09-16 | Catalytic decomposition of an aldehyde to acetic acid and methacrolein |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1047528A true CA1047528A (en) | 1979-01-30 |
Family
ID=4101151
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA209,313A Expired CA1047528A (en) | 1974-09-16 | 1974-09-16 | Catalytic decomposition of an aldehyde to acetic acid and methacrolein |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1047528A (en) |
-
1974
- 1974-09-16 CA CA209,313A patent/CA1047528A/en not_active Expired
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