Distillation: processes – separatory – With disparate physical separation – Utilizing liquid-liquid extracting of distillation product
Reexamination Certificate
2000-08-16
2002-09-03
Manoharan, Virginia (Department: 1764)
Distillation: processes, separatory
With disparate physical separation
Utilizing liquid-liquid extracting of distillation product
C203S049000, C203S063000, C203S064000, C203S059000, C203S060000, C203S062000, C203S067000, C203S068000, C203S069000, C203S070000, C203S075000, C203S077000, C203S080000, C203S078000, C568S366000
Reexamination Certificate
active
06444096
ABSTRACT:
FIELD OF THE INVENTION
This invention pertains to a process for the recovery and purification of cyclobutanone from a crude product mixture obtained from an oxidation product mixture resulting from the oxidation of cyclobutanol to cyclobutanone. More specifically, this invention pertains to the recovery of cyclobutanone in a purity of at least 90 weight percent by a novel combination of distillation steps.
BACKGROUND OF THE INVENTION
Cyclobutanone is a valuable organic intermediate useful in the preparation of a variety of compounds. See, for example, Lee-Ruff, Adv. Strain Org. Chem, (1991), 1, 167 and Bellus et al., Angew Chem., (1988), 100(6), 820. Cyclobutanone can be prepared by the oxidation of cyclobutanol with chromium trioxide and oxalic acid in water as described, for example, by Krumpolic and Rocek in
Organic Synthesis Collective Volumes,
pages 114-116. The chromium trioxide/oxalic acid oxidation is relatively non-selective and produces a dilute aqueous crude cyclobutanone mixture containing many hard-to-separate impurities. Typical impurities in the crude aqueous cyclobutanone include, but are not limited to, cyclopropanemethanol, unreacted cyclobutanol, 3-butene-1-ol, 2-butene-1-ol, cyclopropane carboxaldehyde, cyclopropane carboxylic acid, ethers and mixed ethers of cyclobutanol, cyclopropanemethanol, 3-butene-1-ol, and 2-butene-1-ol; hemi-ketals and ketals of the cyclopropanemethanol, cyclobutanol, 3-butene-1-ol and 2-butene-1-ol with cyclobutanone as well as other unknown compounds with boiling points higher and lower than cyclobutanone. Many of these impurities are color bodies and which cause the cyclobutanone product to be highly colored if not removed.
Krumpolic and Rocek, supra, describe the extraction of the crude cyclobutanone-water mixture with methylene chloride and the drying of the organic phase, comprising cyclobutanone and other organic impurities, over anhydrous magnesium sulfate containing anhydrous potassium carbonate. The dried organic layer is distilled twice to remove methylene chloride and recover the cyclobutanone product. The procedure is said to produce a relatively pure cyclobutanone product, i.e., 98-99 weight percent cyclobutanone. However, this process suffers many disadvantages from a standpoint of practical large-scale production of high-purity cyclobutanone. The extracting agent, methylene chloride, is quite toxic, very volatile, and is costly to handle and dispose of safely. The aforementioned procedure specifies the use of approximately 86 kg of methylene chloride per kg of cyclobutanone produced. Thus, extraction and subsequent distillation equipment required must be very large and expensive relative to the amount of cyclobutanone produced. The authors disclose that cyclobutanone is highly soluble in water and is difficult to extract into methylene chloride at high recoveries. Moreover, the overall recovery of cyclobutanone is low (70-80%), and the authors fail to specify any methods for removing close-boiling impurities such as crotonaldehyde and cyclopropanecarboxaldehyde, as well as color bodies.
French Patent FR 0112261 discloses a process for the preparation of aldehydes or ketones in which molecular oxygen in conjunction with a bimetallic catalyst is used to oxidatively dehydrate primary or secondary, mono- or polyfunctional alcohols that contain two to thirty-six carbon atoms. The water formed is removed in the course of the reaction by azeotropic distillation using an organic solvent chosen in such a way that: (1) the binary azeotrope that the solvent forms with water has a boiling point of at least 50° C., (2) the boiling point of the solvent is less than the boiling point of the alcohol to be dehydrogenated, and (3) the boiling point of the solvent is less than the boiling point of any binary azeotrope that may form between the alcohol and water as well as the alcohol and the organic solvent itself. The organic solvent is specified to have a boiling point between 50° C. and 200° C. and is chosen from among aliphatic, cycloaliphatic, or aromatic hydrocarbons; alkyl or alkenyl esters of aliphatic carboxylic acids; aliphatic, aromatic, or cyclic ethers; aliphatic, cycloaliphatic, or aromatic nitrites; aliphatic, cycloaliphatic, or aromatic ketones. Furthermore, the azeotrope formed between water and the organic solvent must be heterogeneous.
Although FR 0112261 provides a general method for azeotropic distillative dehydration of ketones, the patent specifies that an additional solvent must be added to perform the dehydration of the ketone. Moreover FR 0112261 fails to contemplate methods for obtaining a high purity ketone product. No methods are disclosed for the removal of unreacted alcohol feed material, color bodies, other high and low boiling, or close-boiling impurities in order to obtain a high purity ketone product.
U.S. Pat. No. 2,647,861 discloses a process for the purification of ketones containing water and unreacted alcohol starting material, specifically for methyl ethyl ketone (MEK), methyl propyl ketone (MPK), and methyl butyl ketone (MBK) by two or three column pressure-swing distillation sequence. In the case of MEK, MPK, and MBK, the composition of the ketone-water azeotrope varies significantly with moderate changes in pressure. This patent also fails to contemplate methods for obtaining a high purity ketone product. No methods are disclosed for the removal of color bodies, other high- and low-boiling, or close-boiling impurities in order to obtain a high purity ketone product.
U.S. Pat. No. 2,684,934 discloses a process for the purification of mixtures of MEK and methyl isopropyl ketone containing water and unreacted ethanol and isopropanol by a combination of extractive distillation, extraction, and azeotropic distillation steps with an added solvent. The crude aqueous ketone-alcohol feed is first extractively distilled with water as the extractive distillation solvent. The column base product comprising unreacted ethanol, isopropanol and water is recycled to the ketone formation step, while the MEK-MIPK-water distillate product is countercurrently contacted with n-hexane in an extraction column. The water-rich raffinate comprising some MIPK and MEK is recycled to the extractive distillation column. The hexane-rich extractant, comprising most of the MIPK and MEK in the feed to the extractor, as well as some water, is fed to an azeotropic distillation column where the remaining water is taken overhead as the heterogeneous low-boiling ternary hexane-MEK-water azeotrope. The azeotrope is allowed to phase separate, is decanted, and the organic-rich layer containing most of the MEK and hexane is recycled to the extraction step. The aqueous layer of the decantation is recycled to the extractive distillation step. MEK and MIPK are then separated in a final distillation step.
U.S. Pat. No. 4,186,059 describes a similar solvent-assisted azeotropic distillation and extraction process for MEK dehydration using toluene as the water entrainer in the distillation step and hydrocarbon wax as the extraction solvent. French Patent FR 78 28329 teaches a similar azeotropic distillation processes for the dehydration of MEK using a light hydrocarbon as the water entrainer, preferably n-pentane. Soviet Union patent 1,567,603 teaches the use of diisopropyl ether as the solvent for MEK dehydration.
All of these MEK-related patents teach processes that are unduly complicated, expensive, and unnecessary for cyclobutanone dehydration. While MEK and water form a low-boiling heterogeneous azeotrope, the liquid-liquid region is small with high mutual solubility of MEK and water. Thus MEK is not a favorable entrainer for use in its own dehydration.
BRIEF SUMMARY OF THE INVENTION
We have developed a process for the recovery of cyclobutanone in a purity of at least 90 weight percent by a novel combination of distillation and processing steps. The purification process of the present invention involves a process for the recovery of cyclobutanone in a purity of at least 90 weight percent from a crude product mixture comprising cyclobu
Barnicki Scott Donald
Falling Stephen Neal
Foster Mary Kathleen
Fuller, Jr. Dewey Wayne
Kline Robert Sterling
Blake Michael J.
Eastman Chemical Company
Manoharan Virginia
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