Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2002-05-13
2004-02-24
Shah, Mukund J. (Department: 1624)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C560S221000, C560S238000, C560S300000
Reexamination Certificate
active
06696594
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a process for the conversion of aldehydes to esters, specifically acrolein or methacrolein to methyl acrylate or methyl methacrylate, respectively. In the process, an aldehyde is contacted with an oxidizing agent to form an intermediate and then the intermediate is contacted with a diol or an alcohol to form an ester. Specifically, acrolein or methacrolein is contacted with an oxidizing agent which is also a chlorinating agent, such as t-butyl hypochlorite, and the chlorinated compound is contacted with an alcohol, such as methanol, to form methyl acrylate or methyl methacrylate, respectively.
2. Description of the Prior Art
Manufacture of methyl acrylate (MA) and methyl methacrylate (MMA) can be accomplished by progressive oxidation of propylene to acrolein and to acrylic acid and esterification to methyl acrylate and of isobutylene to methacrolein and methacrylic acid and to methyl methacrylate, respectively. The first oxidation is a catalytic reaction that converts an olefin in the presence of oxygen to an unsaturated aldehyde and water:
H
2
C═CA
x
-CH
3
+O
2
→H
2
C═CA
x
-CHO+H
2
O
where A is hydrogen or an alkyl group.
The catalyst is generally a multi-component mixed metal oxide catalyst, typically molybdenum based.
The second oxidation is also a catalytic reaction that converts an unsaturated aldehyde in the presence of oxygen to an unsaturated carboxylic acid:
H
2
C═CA
x
-CHO+½O
2
→H
2
C═CA
x
-COOH
The catalyst is generally a multi-component mixed metal oxide or heteropoly compound catalyst, also typically molybdenum based.
Esterification of the unsaturated carboxylic acid is also a catalytic reaction that converts the unsaturated carboxylic acid in the presence of an alcohol to an unsaturated ester:
H
2
C═CA
x
-COOH+A′OH→H
2
C═CA
x
-COOA′+H
2
O
where A′ is an alkyl group.
An article entitled “A Novel, Nonoxidative Method for the Conversion of Aldehydes to Esters” by Stephen R. Wilson et al published in J. Org. Chem., vol. 47, pages 1360-1 (1982), disclosed conversion of (cyclobutadiene)iron tricarbonyl to tricarbonyl (methyl 1-4-v-1,3-cyclobutadiene-carboxylate)iron or tricarbonyl (isophorol 1-4-v-1,3-cyclobutadiene-carboxylate)iron with tert-butyl hypochlorite and methanol or isophorol, respectively, and conversion of cinnamaldehyde to methylcinnamate with tert-butyl hypochlorite and methanol. The choice of solvent appeared to control the product obtained. For example, it was reported that the reaction of tert-butyl hypochlorite with cinnamaldehyde in methanol produced 2-chloro-3-methoxy-3-phenylpropanal whereas the reaction of tert-butyl hypochlorite with cinnamaldehyde in carbon tetrachloride produced 1-chloro-3-phenylpropanal. There was no disclosure of the effectiveness of chlorinating aliphatic aldehydes for conversion to esters or of the effect of solvents on such a process.
Hypochlorites have been used in other chemical reactions. U.S. Pat. No. 3,488,394 discloses the hydroxylation of olefins by reacting olefin and a hypochlorite in the presence of OsO
4
while U.S. Pat. No. 3,846,478 discloses the reaction of a hypochlorite and olefin in an aqueous medium and in the presence of OsO
4
catalyst to hydroxylate the olefin. Both of these procedures can employ co-solvents such as t-butyl alcohol. When this is done, it is disclosed that there is some tendency for allylic chlorination of the olefinic compound to occur, e.g., by the action of t-butyl hypochlorite formed from reaction of the t-butyl alcohol and sodium hypochlorite (NaOCl). Alternatively, part of the t-butyl hypochlorite can react with allyl alcohol to form a chlorinated ether.
U.S. Pat. No. 6,127,556 discloses t-butyl hypochlorite as an oxidizing agent in a multi-step conversion of aldehydes to epoxides.
U.S. Pat. No. 4,110,533 discloses t-butyl hypochlorite in a process for the manufacture of enol derivatives and the conversion of a thio grouping into a sulfoxide grouping by oxidation of a 2-cephem compound to the corresponding oxide in the presence of an inert solvent, such as a halogenated hydrocarbon like methylene chloride.
U.S. Pat. No. 4,007,211 discloses t-butyl hypochlorite in process to convert an alpha-thio carboxylic acid to the corresponding ketone by removing the carboxylic carbon by oxidative decarboxylation.
The conversion of aldehyde to ester without the presence of a metal catalyst would be advantageous. Oxidation of the metal sites can result in poor catalyst performance.
OBJECTS OF THE INVENTION
Accordingly, an object of this invention is to provide a process for converting aldehydes to esters with an oxidizing agent and a diol or an alcohol.
And, an object of this invention is to provide an oxidizing agent, preferably one which is also a chlorinating agent, to form an intermediate of an acyl chloride from an aldehyde.
Also, an object of this invention is to provide an anhydrous process for converting aldehydes to esters.
Further, an object of this invention is to provide a process in the absence of solvents for converting aldehydes to esters.
Additionally, an object of this invention is to provide a process for converting aldehydes to esters in a single batch reactor.
SUMMARY OF THE INVENTION
These and other objects are accomplished by a process for producing esters from aldehydes with an oxidizing agent, preferably one which is also a chlorinating agent, and a diol or an alcohol.
This invention relates to a process for producing esters from aldehydes comprising reacting essentially in the absence of water an aldehyde having the general formula of RCHO, wherein R is an alkenyl group or alkyl group having one to six carbon atoms, with an oxidizing agent having the general formula R′
3
COX, wherein R′ is an alkyl group having one to six carbon atoms bonded to a tertiary carbon atom, each R′ being the same or different, and wherein X is a halogen, to form an intermediate and reacting the intermediate with an alcohol having the general formula of R″OH or a diol having the general formula HOR′″OH, wherein R″ is an alkyl group or alkoxy group having one to eight carbon atoms or an aryl group having six to ten carbon atoms and R′″ is an alkyl group having one to eight carbon atoms or an aryl group having six to ten carbon atoms to form an ester having the general formula RCOOR″ or RCOOR′″OH or a diester having the general formula RCOOR′″OOCR.
This invention also relates to a process for producing an ester from an aldehyde comprising (a) contacting an aldehyde having the general formula of RCHO, wherein R is an ethenyl or isopropenyl group, with an oxidizing agent having the general formula R′
3
COX, wherein R′ is an alkyl group having one to six carbon atoms bonded to a tertiary carbon atom, each R′ being the same or different, and wherein X is a halogen, to form an intermediate; and (b) contacting an alcohol having the general formula of R″OH or a diol having the general formula HOR′″OH, wherein R″ is an alkyl group or alkoxy group having one to eight carbon atoms or an aryl group having six to ten carbon atoms and R′″ is an alkyl group having one to eight carbon atoms or an aryl group having six to ten carbon atoms, with the intermediate to form an ester having the general formula RCOOR″ or RCOOR′″OH or a diester having the general formula RCOOR′″OOCR wherein the process is carried out essentially in the absence of water.
The reaction sequence of the present invention is as follows:
DESCRIPTION OF EMBODIMENTS OF THE INVENTION
This invention is generally a process for converting aldehydes to esters by contacting the aldehyde with an oxidizing agent and then with a diol or an alcohol. The oxidizing agent is preferably also a chlorinating agent such as t-butyl hypochlorite.
To achieve the objects of the present invention, the reaction between the a
Au Andrew T.
Flosser David Adam
Lawanier Jean-Pierre
Saudi Basic Industries Corporation
Shah Mukund J.
Tucker Zachary C.
Wheelington Jim
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