DE493268C - Process for the preparation of inactive menthol - Google Patents
Process for the preparation of inactive mentholInfo
- Publication number
- DE493268C DE493268C DER55338D DER0055338D DE493268C DE 493268 C DE493268 C DE 493268C DE R55338 D DER55338 D DE R55338D DE R0055338 D DER0055338 D DE R0055338D DE 493268 C DE493268 C DE 493268C
- Authority
- DE
- Germany
- Prior art keywords
- menthol
- inactive
- preparation
- inactive menthol
- sodium
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C35/00—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a ring other than a six-membered aromatic ring
- C07C35/02—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a ring other than a six-membered aromatic ring monocyclic
- C07C35/08—Compounds having at least one hydroxy or O-metal group bound to a carbon atom of a ring other than a six-membered aromatic ring monocyclic containing a six-membered rings
- C07C35/12—Menthol
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Fats And Perfumes (AREA)
Description
Verfahren zur Darstellung von inaktivem Menthol Bei dem Verfahren nach Patent 489 819 zur Herstellung von inaktivem Menthol (dem Racemat des natürlichen Menthols) durch Reduktion von Thymol mit Wasserstoff bildet sich ein isomeres flüssiges Menthol (Isomenthol). Aus den Hydrierungsgemisch wird gemäß dem Hauptpatent durch Ausfrieren ein kristallinisches Produkt ausgeschieden, welches aus inaktivem Menthol (dem Racemat des natürlichen Menthols) besteht. Die Mutterlaugen enthalten die isomeren Menthole, welche mit dehydrierenden Katalysatoren behandelt werden, worauf die hierbei erhaltenen Ketone in Gegenwart von hy- drierenden Katalysatoren der Einwirkung von Wasserstoff unter Druck ausgesetzt werden und aus dem erhaltenen Mentholgemisch das inaktive Menthol wiederum durch Ausfrieren abgeschieden wird.Process for the preparation of inactive menthol In the process according to patent 489 819 for the preparation of inactive menthol (the racemate of natural menthol) by reducing thymol with hydrogen, an isomeric liquid menthol (isomenthol) is formed. According to the main patent, a crystalline product consisting of inactive menthol (the racemate of natural menthol) is excreted from the hydrogenation mixture by freezing out. The mother liquors contain the isomeric mentholes, which are treated with dehydrogenating catalysts, whereupon the ketones obtained in this way are exposed to the action of hydrogen under pressure in the presence of hydrogenating catalysts and the inactive menthol is again separated out by freezing out of the menthol mixture obtained.
Das vorliegende Verfahren zur Umwandlung des isomeren flüssigen Menthols besteht darin, daß man dieses auf höhere Temperaturen oberhalb r oo°, vorteilhaft etwa Zoo bis 300°, bei Gegenwart von Mentholnatrium oder -kalium erhitzt. Beispiel Aus 25 kg Thymol erhält man durch Hydrierung mit Nickel als Katalysator im Autoklaven unter Druck ein Mentholgemisch, aus dem durch fraktionierte Destillation z fl kg inaktives Menthol erhalten werden-. Die@üei der Fraktionierung abfallenden ro kg flüssiges Menthol (Isomenthol) werden mit 300 g metallischem Natrium in Reaktion gebracht und 2o Stunden auf 300° erhitzt. Darauf wird das Reaktionsprodukt, welches aus etwa Soli, inaktivem Menthol und 5o°/" flüssigem Isrnnenthol besteht, mit Wasserdampf abgetrieben -und der fraktionierten Destillation unterworfen. Man erhält etwa Soli, inaktives Menthol von höherem Schmelzpunkt.The present process for converting the isomeric liquid menthol consists in heating it to higher temperatures above r oo °, advantageously about zoo to 300 °, in the presence of menthol sodium or potassium. EXAMPLE A menthol mixture is obtained from 25 kg of thymol by hydrogenation with nickel as a catalyst in an autoclave under pressure, from which 2 kg of inactive menthol are obtained by fractional distillation. The ro kg of liquid menthol (isomenthol) falling off during the fractionation are reacted with 300 g of metallic sodium and heated to 300 ° for 20 hours. The reaction product, which consists of about soli, inactive menthol and 50% liquid isinenthol, is then driven off with steam and subjected to fractional distillation. Soli, inactive menthol of higher melting point, for example, is obtained.
Das mit Natrium zu behandelnde Isomenthol stellt ein Gemisch verschiedener isomerer Menthole dar. Bei der Einwirkung von Natrium entstehen daher die entsprechenden Natriumverbindungen dieser verschiedenenMenthole. Das Isomenthol kann gegebenenfalls noch Menthol enthalten.The isomenthol to be treated with sodium is a mixture of different isomeric mentholes. The action of sodium therefore produces the corresponding Sodium compounds of these various mentholes. The isomenthol can optionally still contain menthol.
Claims (1)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DER55338D DE493268C (en) | 1922-03-12 | 1922-03-12 | Process for the preparation of inactive menthol |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DER55338D DE493268C (en) | 1922-03-12 | 1922-03-12 | Process for the preparation of inactive menthol |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| DE493268C true DE493268C (en) | 1930-03-08 |
Family
ID=7409936
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DER55338D Expired DE493268C (en) | 1922-03-12 | 1922-03-12 | Process for the preparation of inactive menthol |
Country Status (1)
| Country | Link |
|---|---|
| DE (1) | DE493268C (en) |
-
1922
- 1922-03-12 DE DER55338D patent/DE493268C/en not_active Expired
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