DE516651C - Process for the preparation of inactive menthol - Google Patents

Process for the preparation of inactive menthol

Info

Publication number
DE516651C
DE516651C DER75879D DER0075879D DE516651C DE 516651 C DE516651 C DE 516651C DE R75879 D DER75879 D DE R75879D DE R0075879 D DER0075879 D DE R0075879D DE 516651 C DE516651 C DE 516651C
Authority
DE
Germany
Prior art keywords
menthol
mixture
liquid
inactive
preparation
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
Application number
DER75879D
Other languages
German (de)
Inventor
Dr Karl Schoellkopf
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
RHEINISCHE KAMPFER FABRIK
Original Assignee
RHEINISCHE KAMPFER FABRIK
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by RHEINISCHE KAMPFER FABRIK filed Critical RHEINISCHE KAMPFER FABRIK
Priority to DER75879D priority Critical patent/DE516651C/en
Application granted granted Critical
Publication of DE516651C publication Critical patent/DE516651C/en
Expired legal-status Critical Current

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)
  • Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Description

Verfahren zur Darstellung von inaktivem Menthol Es wurde gefunden, daß das nach dem Verfahren des Hauptpatentes 489 819 zunächst erhältliche flüssige, isomere Mentholgemisch, das technisch wegen seiner schlechten geruchlichen Eigenschaft nur geringen Wert hat, auch unmittelbar in inaktives Menthol (das Racemat des natürlichen Menthols) übergeführt werden kann, indem man es unmittelbar unter Druck mit Wasserstoff in Gegenwart von Katalysatoren, die für die Hydrierung geeignet sind, nochmals behandelt. Man erhält dann wieder ein Mentholgemisch von der gleichen Zusammensetzung wie das Reduktionsprodukt des Thymols, aus dem sich, wie nach dem Verfahren des Hauptpatentes 489 8z9, das inaktive Menthol vom höheren-Schmelzpunkt und von dem Geruch und Geschmack des natürlichen aktiven Menthols gewinnen läßt.Process for the preparation of inactive menthol It was found that the liquid initially obtainable according to the process of the main patent 489 819, isomeric mixture of menthol, which is technically because of its bad odorous property has little value, even directly in inactive menthol (the racemate of the natural Menthols) can be converted by placing it directly under pressure with hydrogen treated again in the presence of catalysts which are suitable for the hydrogenation. A menthol mixture of the same composition as that is then obtained again Reduction product of thymol, from which, as in the process of the main patent 489 8z9, the inactive menthol from the higher melting point and from the smell and taste of natural active menthol.

Die Behandlung des flüssigen, isomeren Mentholgemisches kann man zweckmäßig auch derartig ausführen, daß man das flüssige Mentholgemisch dem Thymol zumengt, die Mischung unter Druck mit Wasserstoff in Gegenwart von Katalysatoren behandelt und aus dem dann erhaltenen Mentholgemisch in der erwähnten Weise das inaktive Menthol vom höheren Schmelzpunkt gewinnt. Es war nicht vorauszusehen, daß das flüssige, isomere Mentholgemisch bei Behandlung mit Katalysatoren Lund Wasserstoff sich in das Racemat des natürlichen Menthols umlagern läßt. Beispiel 25 kg desflüssigen, isomerenMentholgemisches werden in einem Autoklaven mit 500 g Nickelkatalysator bei etwa 200° mit Wasserstoff unter einem Druck von 5 bis 3o Atm. gut verrührt. Nach beendeter Behandlung wird der Autoklaveninhalt durch Destillation oder Filtration vom Katalysator befreit. Aus dem so erhaltenen Mentholgemisch wird das inaktive Menthol vom höheren Schmelzpunkt durch Ausfrieren und Abschleudern in der Kälte von dem zurückbleibenden flüssigen, isomeren Mentholgemisch getrennt.The treatment of the liquid, isomeric menthol mixture can expediently also be carried out in such a way that the liquid menthol mixture is added to the thymol, the mixture is treated under pressure with hydrogen in the presence of catalysts and the inactive menthol of the higher melting point is obtained from the menthol mixture obtained in the manner mentioned wins. It was not foreseeable that the liquid, isomeric menthol mixture could be rearranged into the racemate of natural menthol on treatment with catalysts L and hydrogen. Example 25 kg of the liquid, isomeric menthol mixture are in an autoclave with 500 g of nickel catalyst at about 200 ° with hydrogen under a pressure of 5 to 30 atm. well mixed. After the treatment has ended, the contents of the autoclave are freed from the catalyst by distillation or filtration. From the menthol mixture obtained in this way, the inactive menthol with the higher melting point is separated from the remaining liquid, isomeric menthol mixture by freezing out and spinning off in the cold.

Die oben beschriebene Behandlung des flüssigen, isomeren Mentholgemisches kann auch gemeinsam mit Thymol in der gleichen Weise erfolgen.The treatment of the liquid, isomeric menthol mixture described above can also be done together with thymol in the same way.

Claims (1)

PATENTANSPRACHE i. Verfahren zur Darstellung von inaktivem Menthol, dem Racemat des natürlichen Menthols, gemäß Patent 489 81g, dadurch gekennzeichnet, daß_ man dägl.nach dem VerfUreh des- IHaiiptpatentes zunächst erhältliche flüssige, isomere Mentholgemisch unmittelbar nochmals mit Wasserstoff unter Druck bei Gegenwart von Katalysatoren behandelt. 2. des Verfahrens nach Anspruch z, dadurch gekennzeichnet, daß die Behandlung des flüssigen, isorneren Mentholgemisches mit Wasserstoff unter Druck in Gegenwart von Katalysatoren gemeinsam mit der Behandlung des Thymols erfolgt. PATENT APPEAL i. Process for the preparation of inactive menthol, the racemate of natural menthol, according to patent 489 81g, characterized in that the liquid, isomeric menthol mixture initially obtainable after the process of the patent patent is immediately treated again with hydrogen under pressure in the presence of catalysts. 2. The method according to claim z, characterized in that the treatment of the liquid, isorneren menthol mixture with hydrogen under pressure in the presence of catalysts takes place together with the treatment of the thymol.
DER75879D 1922-10-11 1922-10-11 Process for the preparation of inactive menthol Expired DE516651C (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
DER75879D DE516651C (en) 1922-10-11 1922-10-11 Process for the preparation of inactive menthol

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DER75879D DE516651C (en) 1922-10-11 1922-10-11 Process for the preparation of inactive menthol

Publications (1)

Publication Number Publication Date
DE516651C true DE516651C (en) 1931-01-26

Family

ID=7415201

Family Applications (1)

Application Number Title Priority Date Filing Date
DER75879D Expired DE516651C (en) 1922-10-11 1922-10-11 Process for the preparation of inactive menthol

Country Status (1)

Country Link
DE (1) DE516651C (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1189073B (en) * 1958-07-10 1965-03-18 Glidden Co Process for the preparation of d, l-menthol by racemizing d- or l-menthol, -neomenthol, -isomenthol or -neoisomenthol

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1189073B (en) * 1958-07-10 1965-03-18 Glidden Co Process for the preparation of d, l-menthol by racemizing d- or l-menthol, -neomenthol, -isomenthol or -neoisomenthol

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