Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acid esters
Reexamination Certificate
2002-03-27
2003-12-02
Raymond, Richard L. (Department: 1623)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acid esters
C560S265000, C568S302000
Reexamination Certificate
active
06657075
ABSTRACT:
FIELD OF THE INVENTION
This invention pertains to a process for the production of tertiary butyl esters. More specifically, this invention pertains to a continuous process for the preparation of tertiary butyl esters through the reaction of a ketene with tertiary butyl alcohol containing a finite amount of water.
BACKGROUND OF THE INVENTION
Carboxylic acid esters of tertiary butyl alcohol are useful for the production of agrochemicals, coatings, dyes, and solvents. There are several documented methods for the production of tertiary butyl esters. One well-known method for the preparation of tertiary butyl acetate (t-butyl acetate) is by the reaction of isobutylene with acetic acid in the presence of a variety of catalysts. Some of the many types of catalysts used for this reaction include metal silicates, cation exchange resins, acidic ion-exchange resins, sulfuric or other protic acids, as well as modified copolymers of styrene and divinylbenzene.
U.S. Pat. No. 5,866,714 describes a method for producing tertiary butyl acetate by the reaction of isobutylene with acetic acid using byproduct tertiary butyl alcohol to suppress olefin polymerization.
U.S. Pat. No. 4,360,406 describes a method for producing tertiary butyl alcohol and tertiary butyl acetate by the reaction of isobutylene with an aqueous solution of an aliphatic carboxylic acid in the presence of an acidic ion-exchange resin. In this process the t-butyl acetate is produced as a minor impurity, which is removed from the process by azeotropic distillation with water.
U.S. Pat. No. 4,009,203 describes a process for producing esters, including t-butyl acetate, by the reaction of an olefin with a halogenated aliphatic, halogenated aromatic or alkenic carboxylic acid in the presence of pre-formed acyloxystannic trihalide.
U.S. Pat. No. 3,102,905 describes a process for producing t-butyl acetate by the reaction of isobutylene and acetic acid in the presence of an organic sulfonic acid in the liquid phase. The crude product is then purified by means of distillation to give t-butyl acetate free of isobutylene.
U.S. Pat. No. 3,096,365 describes a process for producing tertiary esters from olefins and carboxylic acids in the presence of a polyvalent metal silicate catalyst. In this process a tertiary olefin is contacted with a carboxylic acid, in the presence of the catalyst, at temperatures not exceeding 300° F. to yield the corresponding tertiary ester.
U.S. Pat. No. 3,072,714 describes a process for separating esters from a mixture comprising the said ester, sulfuric acid, and an alkanoic acid. The ester is produced from the sulfuric acid catalyzed reaction of the alkanoic acid with an olefin. The ester is recovered by phase separation after treating the crude reaction mixture with an aqueous alkaline solution.
U.S. Pat. No. 3,055,934 describes a method for producing tertiary esters from tertiary olefins in the presence of sulfuric acid. In this process a tertiary olefin is condensed with an aliphatic hydrocarbylmonocarboxylic acid in the presence of sulfuric acid to produce the corresponding tertiary alkyl ester. The crude tertiary ester is recovered by phase separation after extraction with water.
U.S. Pat. No. 3,053,887 describes a method of producing a t-butyl ester from the reaction of an alkanoic acid with isobutylene in the presence of a catalyst. In this process isobutylene is reacted with a lower alkanoic acid in the presence of a sulfonated copolymer of styrene and a cross-linking compound consisting of divinylbenzene at a temperature below 5° C.
U.S. Pat. No. 3,031,495 describes a process for producing t-butyl acetate by the reaction of acetic acid with a tertiary olefin in the presence of a catalyst. In this process the acetic acid is contacted with the tertiary olefin at a temperature of 0-60° C. and in the presence of a catalyst consisting of a divinylbenzene cross-linked polystyrene sulfonic acid cationic exchange resin containing water.
In the related art described above, isobutylene (or other tertiary olefins) is reacted with acetic acid (or other carboxylic acids) in the presence of strongly acidic catalysts to yield t-butyl acetate (or other tertiary esters).
Another known method for producing esters is by the reaction of acetic acid with alcohols. The reaction of acetic acid with many primary and secondary alcohols proceeds readily, without catalyst, to yield the corresponding ester and water (byproduct). The reaction of tertiary alcohols with acetic acid, however, does not proceed at useful rates without the use of a strong acid catalyst. With t-butyl alcohol, the reaction of acetic acid proceeds smoothly with a variety of strong acid catalysts but yields are often low due to the formation of unwanted by-products, especially isobutylene. When tertiary butyl alcohol is reacted with acetic acid in the presence of strongly acidic catalysts, a large amount of isobutylene gas is formed from the acid-catalyzed dehydration of tertiary butyl alcohol. Due to the formation of the isobutylene, this process requires special equipment that allows for the recovery of the isobutylene off-gas in a safe manner and results in reduced yields.
The production of t-butyl acetate from acetic acid and tertiary butyl alcohol is described in several patents. U.S. Pat. No. 5,151,547 discloses a process for producing an organic carboxylic acid ester from an organic carboxylic acid and an alcohol in the presence of a catalytic amount of sulfuric acid in the gas phase. As described above, when tertiary butyl alcohol is reacted with acetic acid in the presence of a variety of acid catalysts, isobutylene gas was a major by-product. The separation of the by-product gas from the corresponding ester requires special equipment to allow for the recovery of the gas in a safe manner.
U.S. Pat. No. 3,590,073 discloses a method of producing t-butyl acetate from the reaction of acetic acid and tertiary butyl alcohol in the presence of a sulfonic acid cation exchange resin. When this method of production of t-butyl acetate is employed, temperatures exceeding >40° C. causes extensive decomposition of the product to isobutylene and acetic acid, which lowers yield dramatically.
German Patent Application No. 3,636,754 describes a continuous method of preparation of alkyl acetate from an alcohol and acetic acid in the presence of a mineral acid catalyst to yield the corresponding crude acetic acid ester. The crude ester is then purified by distillation.
In the related art described above, t-butyl acetate is produced by the reaction of a carboxylic acid with an alcohol in the presence of strong Lewis or mineral acid catalysts.
Another known method for the production of t-butyl acetate is by the reaction of acetic anhydride with tertiary butyl alcohol. This reaction proceeds without catalyst to yield t-butyl acetate and acetic acid. The major drawback of this method for producing t-butyl acetate is that for every mole of product produced, a mole of acetic acid by-product is also produced. A method for recovering the acetic acid must be developed to make the process economical. Another major drawback of this method for producing t-butyl acetate is that the reaction is somewhat sluggish, without the use of a catalyst, which restricts production rates. When a catalyst is used to improve the reaction rate, a variety of unwanted by-products are often produced making the production of pure t-butyl acetate more difficult without added purification equipment.
U.S. Pat. No. 3,489,796 describes a method for producing tertiary amyl acetate from acetic anhydride and tertiary amyl alcohol using hydrochloric acid as a catalyst. This method of producing tertiary amyl acetate gives product in good yield and high purity after fractional distillation.
In the related art discussed above, t-butyl acetate (or other tertiary esters) is produced by the reaction of acetic anhydride with tertiary butyl alcohol. The reaction between acetic anhydride and tertiary alcohols, including tertiary butyl alcohol, is somewhat sluggish and requires the use of an added catalyst to incre
Cook Steven Leroy
Turner Phillip Wayne
Williams Kevin Alan
Eastman Chemical Company
Graves, Jr. Bernard J.
Middlemas Eric D.
Raymond Richard L.
Tucker Zachary C.
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