Claims
- 1. In a process for selective crystallization of 2,6-dialkyl-naphthalenes selected from the group consisting of methyl-n-propyl-naphthalene, methyl-isopropyl-naphthalene, methyl-n-butyl-naphthalene, methyl-isobutyl-naphthalene, ethyl-isopropyl-naphthalene, ethyl-n-butyl-naphthalene, di-n-propyl-naphthalene, diisopropyl-naphthalene, di-n-butyl-naphthalene and diisobutyl-naphthalene from their isomeric mixtures from a polar solvent solution at a temperature of 25.degree. to -30.degree. C., the improvement comprising effecting the crystallization with constant stirring to obtain the 2,6-dialkyl naphthalene in a high degree of purity.
- 2. The process of claim 1 wherein the ratio of isomer mixture to solvent lies in the range from 1 to 0.5-4.0.
- 3. The process of claim 1 wherein the ratio of isomer mixture to solvent lies in the range from 1 to 2.
- 4. The process of claim 1 wherein the cooling rate is 2.degree. to 15.degree. C. per hour.
- 5. The process of claim 1 wherein the dissolved isomer mixture is cooled with stirring at a cooling rate of 2.degree. to 15.degree. C. per hour, and pure 2,6-dialkyl-naphthalene is used to seed the solution before the beginning of crystallization.
- 6. The process of claim 1 wherein the 2,6-isomer is obtained from dialkyl-naphthalene mixture with a 2,6-dialkyl-naphthalene content of more than 10% by weight.
- 7. The process of claim 1 wherein 2,6-diisopropyl-naphthalene is obtained in the presence of 1,5-diisopropyl-naphthalene.
- 8. The process of claim 1 wherein 2-isopropyl-6-methyl-naphthalene is obtained.
Priority Claims (1)
Number |
Date |
Country |
Kind |
3531559 |
Sep 1985 |
DEX |
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PRIOR APPLICATION
This application is a continuation of copending U.S. patent application Ser. No. 901,182 filed Aug. 27, 1986, now abandoned.
US Referenced Citations (6)
Foreign Referenced Citations (1)
Number |
Date |
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730740 |
Mar 1966 |
CAX |
Continuations (1)
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Number |
Date |
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Parent |
901182 |
Aug 1986 |
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