GB341654A - A process for preparing pure inactive menthol - Google Patents
A process for preparing pure inactive mentholInfo
- Publication number
- GB341654A GB341654A GB37532/29A GB3753229A GB341654A GB 341654 A GB341654 A GB 341654A GB 37532/29 A GB37532/29 A GB 37532/29A GB 3753229 A GB3753229 A GB 3753229A GB 341654 A GB341654 A GB 341654A
- Authority
- GB
- United Kingdom
- Prior art keywords
- inactive
- menthol
- neomenthol
- alcohol
- thymol
- 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)
Abstract
Pure inactive menthol is prepared by subjecting the hydrogenation products of thymol, menthones and menthenones or the isomerization products of inactive isomeric menthols to partial esterification, purifying the resulting esters by crystallization and then saponifying. The partial esterification process frees the starting material from neomenthol, whilst the subsequent crystallization step eliminates isomenthol. According to the examples, (1) thymol is hydrogenated, the product heated with insufficient phthalic anhydride for complete esterification and then distilled with steam to remove the unesterified menthol fraction consisting chiefly of neomenthol; the remaining ester is recrystallized twice from alcohol and finally saponified; (2) inactive neomenthol is heated with sodium and the isomerization product, after being steam distilled, then esterified with phthalic anhydride as before; on adding alcohol to the mass, the acid phthalic acid ester of inactive menthol crystallizes out; this is twice recrystallized from alcohol and then saponified. Specifications 289,125, 289,126 and 297,019, [all in Class 2 (iii), Dyes &c.], are referred to.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE341654X | 1929-01-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB341654A true GB341654A (en) | 1931-01-22 |
Family
ID=6234967
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB37532/29A Expired GB341654A (en) | 1929-01-28 | 1929-12-06 | A process for preparing pure inactive menthol |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB341654A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105461516A (en) * | 2015-11-20 | 2016-04-06 | 安徽海华科技股份有限公司 | A synthetic process of L-menthol |
-
1929
- 1929-12-06 GB GB37532/29A patent/GB341654A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105461516A (en) * | 2015-11-20 | 2016-04-06 | 安徽海华科技股份有限公司 | A synthetic process of L-menthol |
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