Chemistry of hydrocarbon compounds – Purification – separation – or recovery – By addition of extraneous agent – e.g. – solvent – etc.
Reexamination Certificate
1999-07-29
2002-06-04
Griffin, Walter D. (Department: 1764)
Chemistry of hydrocarbon compounds
Purification, separation, or recovery
By addition of extraneous agent, e.g., solvent, etc.
C585S857000, C585S858000
Reexamination Certificate
active
06399847
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to a method of purifying 1,3,5-triisopropylbenzene.
BACKGROUND OF THE INVENTION
1,3,5-Triisopropylbenzene is a known compound that can be commercially purchased. 1,3,5-Triisopropylbenzene is used in the synthesis of 2,6-bis(1-methylethyl)phenyl[[2,4,6-tris(1-methylethyl)phenyl]acetyl]sulfamate, which can be used as a lipid regulator. Because 2,6-bis(1-methylethyl)phenyl[[2,4,6-tris(1-methylethyl)phenyl]acetyl]sulfamate is a pharmaceutical intended for human use, its purity must be high. Therefore, in synthesizing 2,6-bis(1-methylethyl)phenyl[[2,4,6-tris(1-methylethyl)phenyl]acetyl]sulfamate, the purity of starting materials and intermediates in the synthesis is important. Thus, it is desirable to obtain 1,3,5-triisopropylbenzene having a high purity.
It is difficult to obtain 1,3,5-triisopropylbenzene having a purity of greater than 98% of 1,3,5-triisopropylbenzene. For example, 1,3,5-triisopropylbenzene can be purified to greater than 98% by vacuum distillation, but the distillation apparatus must contain over 120 theoretical plates, which is expensive and time consuming. Moreover, commercially available 1,3,5-triisopropylbenzene typically is not as pure as desired and must be further purified. For example, 1,3,5-triisopropylbenzene having a purity of only 97.6% can be purchased from Aldrich, Milwaukee, Wis.
The present invention provides a simple and efficient method for purifying 1,3,5-triisopropylbenzene to purities greater than 97.6% of 1,3,5-triisopropylbenzene.
SUMMARY OF THE INVENTION
The present invention provides a method of purifying 1,3,5-triisopropylbenzene that comprises combining impure 1,3,5-triisopropylbenzene with a sulfonating agent to form a reaction mixture, mixing the reaction mixture at a temperature of about 0° C. or above; and collecting the purified 1,3,5-triisopropylbenzene.
In a preferred embodiment of the method, the sulfonating agent comprises chlorosulfonic acid.
In another preferred embodiment, the sulfonating agent is about 20 mol percent of the impure 1,3,5-triisopropylbenzene.
In another preferred embodiment, the sulfonating agent is in the range of about 15 mol percent to about 30 mol percent of the impure 1,3,5-triisopropylbenzene.
In another preferred embodiment, the reaction mixture is mixed at a temperature in the range of about 0° C. to about 50° C.
In another preferred embodiment, the reaction mixture is mixed at a temperature in the range of about 20° C. to about 30° C.
In another preferred embodiment, the reaction mixture is mixed at room temperature.
In another preferred embodiment, the sulfonating agent comprises fluorosulfonic acid or sulfuric acid.
In another preferred embodiment, the reaction mixture is mixed for at least 5 minutes.
In another preferred embodiment, the reaction mixture is mixed for about 5 minutes to about 24 hours.
In another preferred embodiment, the reaction mixture is mixed for about 5 minutes to about 60 minutes.
In another preferred embodiment, the purified 1,3,5-triisopropylbenzene is collected by extracting the reaction mixture first with water, second with a base or an aqueous alcoholic solution, and last with water.
In another preferred embodiment, the purified 1,3,5-triisopropylbenzene is collected by extracting the reaction mixture with a base or an aqueous alcoholic solution.
In another preferred embodiment, the base is sodium hydroxide.
In another preferred embodiment, the sodium hydroxide has a concentration of about 5 percent to about 50 percent by weight sodium hydroxide to water.
In another preferred embodiment, the sodium hydroxide has a concentration of about 5 percent to about 20 percent by weight sodium hydroxide to water.
In another preferred embodiment, the sodium hydroxide has a concentration of about 5 percent by weight sodium hydroxide to water.
In another preferred embodiment, the base comprises sodium bicarbonate, ammonia or sodium hydroxide, or mixtures thereof.
In another preferred embodiment, the aqueous alcoholic solution is a methanol and water solution.
In a more preferred embodiment, the methanol and water solution is a 50 percent by volume methanol to water solution.
In another preferred embodiment, the base is 5 percent by weight sodium bicarbonate to water, or 30 percent by weight ammonia to water.
In a most preferred embodiment, the present invention provides a method of purifying 1,3,5-triisopropylbenzene that comprises combining impure 1,3,5-triisopropylbenzene with about 20 mole percent chlorosulfonic acid to the 1,3,5-triisopropylbenzene to form a reaction mixture, mixing the reaction mixture at a temperature in the range of about 0° C. to about 50° C. for a time in the range of about 10 minutes to about 24 hours, and collecting the purified 1,3,5-triisopropylbenzene by first extracting the reaction mixture with water, next extracting the reaction mixture with sodium hydroxide having a concentration in the range of about 5 percent to about 50 percent by weight sodium hydroxide to water, and last extracting the reaction mixture with water.
DETAILED DESCRIPTION OF THE INVENTION
The present invention provides a method of purifying 1,3,5-triisopropylbenzene that comprises combining impure 1,3,5-triisopropylbenzene with a sulfonating agent to form a reaction mixture, mixing the reaction mixture at a temperature at about 0° C. or above, and collecting the purified 1,3,5-triisopropylbenzene.
In general, impure 1,3,5-triisopropylbenzene is combined with a sulfonating agent in a suitable container such as a round-bottomed flask to form a reaction mixture, and the mixture is mixed by stirring or shaking or the like.
The term “impure 1,3,5-triisopropylbenzene” means 1,3,5-triisopropylbenzene that contains impurities that are desired to be removed. For example, 1,3,5-triisopropylbenzene that has a purity of 97.6% with respect to 1,3,5-triisopropylbenzene can be purchased from Aldrich, Milwaukee, Wis. However, it is desirable to have a purity of 98%. Preferably, the purity of the 1,3,5-triisopropylbenzene is greater than 98% and most preferably greater than 99%. The purities expressed herein are area percents obtained by vapor phase chromatography as set forth below.
The sulfonating agent can be selected from those sulfonating agents known to those skilled in the art. The sulfonating agent is preferably inexpensive and should provide for greater sulfonation of the impurities than of 1,3,5-triisopropylbenzene. In general, the major impurities seen in impure 1,3,5-triisopropylbenzene include 1,2,4-triisopropylbenzene and ethyldiisopropylbenzenes. Examples of suitable sulfonating agents include, but are not limited to, chlorosulfonic acid, fluorosulfonic acid, sulfur trioxide and sulfuric acid. Preferably, the sulfonating agent is chlorosulfonic acid.
The sulfonating agent is combined with impure 1,3,5-triisopropylbenzene in an amount that is in the range of about 15 mol to about 50 mole percent sulfonating agent to 1,3,5-triisopropylbenzene. Preferably, the sulfonating agent is used in an amount that is in the range of about 15 mol to about 30 mol percent sulfonating agent to 1,3,5-triisopropylbenzene. In a preferred embodiment, the sulfonating agent is chlorosulfonic acid, and the amount of the chlorosulfonic is 20 mol percent with respect to the 1,3,5-triisopropylbenzene.
The mixture of 1,3,5-triisopropylbenzene and the sulfonating agent are mixed by methods that are well-known to those skilled in the art at a temperature in the range of about 0° C. or above. Preferably, the temperature of the reaction mixture is in the range of about 0° C. to about 50° C. More preferably, the temperature of the reaction mixture is in the range of about 20° C. to 30° C. Most preferably, the temperature of the reaction mixture is about room temperature. In general, room temperature is about 23° C. However, room temperature can vary a few degrees. For example, room temperature can include the temperatures in the range of about 25° C. to about 20° C.
The reaction mixture is mixed at the desired t
Crumbaugh Gretchen
Schweiss Dieter
Walker Jonathan Charles
Ashbrook Charles W.
Griffin Walter D.
Kurlandsky David R.
Nguyen Tam M.
Warner-Lambert & Company
LandOfFree
Method of purifying 1,3,5-triisopropylbenzene does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of purifying 1,3,5-triisopropylbenzene, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of purifying 1,3,5-triisopropylbenzene will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2967862