DE1271707B - Process for the preparation of methyl isogeraniol - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

German class:

Number:
File number:
Registration date:
Display day:

C 07c

ClIb

12 ο-19/03

23a-6

P 12 71707.6-42 (J 29588)

December 13, 1965

4th July 1968

Many terpenes and terpene derivatives are used as fragrances and in the manufacture of fragrance compositions usable because of their valuable aromatic properties. So are terpene derivatives, such as alcohols and aldehydes, valuable and useful fragrances. Such a particularly valuable substance is 2-isopropenyl-5-methylen-6-hepten-l-ol, which is also known as "methyl isogeraniol".

Methyl isogeraniol can be prepared from myrcene and formaldehyde according to US Pat. No. 3,140,311. In the process, formaldehyde is added in the presence of boiling acetic acid as a solvent, myrcene. This process produces a mixture of methyl pentenyl dihydropyrans, primary acyclic C _u alcohols and esters of these alcohols. Methyl isogeraniol is one of the _{C u} -alcohols produced according to this process _{, but this C u} -alcohol is formed in relatively small amounts.

The process of the invention provides methyl isogeraniol and useful methyl isogeraniol esters in much higher yields than the prior art processes.

The process according to the invention for the preparation of methyl isogeraniol and its esters with a lower carboxylic acid is characterized in that myrcene sulfone is reacted with formaldehyde or a formaldehyde solution in equimolar amounts, optionally in the presence of a lower carboxylic acid or its anhydride at temperatures below about 90 ° C and the obtained compound at 160 to 220 ⁰ C pyrolyzed.

Myrcene sulfone, the starting material for the process according to the invention, can easily be prepared from 2-methyl-6-methylene-2,7-octadiene, whose common name is myrcene, as described in US Pat. No. 3,075,033, getting produced.

In this process, about 1% of an inhibitor, such as hydroquinone or phenyl- / S-naphthylamine, is added to the commercially available myrcene to prevent polymerization and polysulfone formation, and the mixture is in the presence of an excess of sulfur dioxide in a closed vessel at 60 Stirred up to 100 ° C under autogenous pressure for 2 to 6 hours. After cooling and removing the excess SO ₂ , all unreacted material is _{removed by distilling the SO 2} at pressures below atmospheric pressure. Other methods of making myrcene sulfone will be apparent to those skilled in the art, and any myrcene sulfone is suitable for use in the practice of the present invention.

Methylisogeraniol can be obtained in good yield by mixing approximately equimolar amounts of formaldehyde and

Process for the production of methyl isogeraniol

Applicant:

International Flavors & Fragrances Inc.,

New York, N.Y. (V. St. A.)

Representative:

Dr. F. Zumstein,

Dipl.-Chem. Dr. rer. nat. E. Assmann,

Dipl.-Chem. Dr. R. Koenigsberger

and Dipl.-Phys. R. Holzbauer, patent attorneys,

8000 Munich 2, Bräuhausstr. 4th

Named as inventor:
Peter William Drake Mitchell,
Lewis George Augustine,
Atlantic Highlands, NJ (V. St. A.)

Claimed priority:
V. St. v. America December 18, 1964
(419 579)

Myrcene sulfone can be obtained, but a slight molar excess of formaldehyde is preferred used. In the present invention, "formaldehyde" includes aqueous solutions of formaldehyde, Paraformaldehyde and other substances that produce formaldehyde under the reaction conditions. The usage paraformaldehyde is preferred in the practice of the present invention.

Improved yields of methyl isogeraniol can be obtained in the practice of the present invention when the reaction is carried out in the presence of a solvent. Suitable solvents are organic carboxylic acids and anhydrides and their mixtures, preferably lower alkanecarboxylic acids and their anhydrides and their mixtures. Lower alkanecarboxylic acids of 1 to carbon atoms are generally preferred. Examples of for use as a solvent in

809 568/576

3 4

the implementation of the present invention ge Although the pyrolysis directly with the reaction

Suitable organic carboxylic acids are formic acid, when the reaction is carried out in the presence of a product Acetic acid, trimethyl acetic acid and propionic acid. The sulfuric acid catalyst has been carried out Use of acid anhydrides, such as propionic acid, has been found that

anhydride, is preferred, above-average results are obtained when the

Using acetic anhydride reaction mixture, nits are first neutralized with

obtained drid as a solvent. alkaline substances and washing with water from acidic

It is generally preferred that the reactants are freed.

medium a strong mineral acid, such as concentrated If the reaction to produce the methyliso-sulfuric acid, Phosphoric acid, hydrochloric acid io geraniols in the presence of an organic carboxylic acid and the like, especially when acetic acid, tri- or anhydride has been carried out methyl acetic acid, propionic acid or their anhydrides, the sulfone addition product in the form of the ester can be used in the reaction medium. A preferred acid or anhydride. It is added reaction medium consists of acetic anhy- preferred to drive off the sulfur dioxide while drid that contains concentrated sulfuric acid. 15 the product is in the form of an ester, so that the

The reaction is exothermic and there should therefore be hydroxyl group protected during pyrolysis.

Cooling devices should be provided to keep the tempe- As stated above, the only additional ones

keep the temperature in the desired range. Cooling steps include a distillation or other purification

is necessary to set the reaction temperature at or of the substance which may be necessary for a given purpose

to be kept below 90 ° C. It is preferred that the temperature may be 20 if the methyl isogeraniol ester is desired.

below 90 ° C, because at and above this tempe-. The methyl isogeraniol esters are valuable fragrances,

temperature is the rate of decomposition of myrcene, for example, the acetic acid ester of methyl

sulfons rises and becomes significant. As a result, isogeraniols become a natural and peculiar one

the reactants and the medium if a smell and is also a fragrance. He has an

such is used, preferably at temperatures 25 pleasant, fresh, plant-like odor, similar

kept in the range of about 10 to about 80 ° C, such as crysanthemums and colognes, and is as

excellent results ranging from about 25 to a component of geranium, neroli and bergamot

about 4O ⁰ C are obtained. The reaction becomes useful in perfumes.

Depending on the temperature, at least 3 hours. If the methyl isogeraniol itself is desired, the

the carried out. Albeit in a very long 30 ester to be saponified. Solutions are preferred

Time range no bad results obtained from alkali metal hydroxides in alcohols, such as

little is generally gained with ethanol, ethanol, or isopropanol, for this purpose

the respondents used in longer than 48 hours.

Keep in touch. Preferably the reac- After saponification, the methyl isogeraniol can

tion time about 4 to about 12 hours. 35 can be cleaned according to standard methods.

The first step of the reaction yields a myrcene under certain reaction conditions in some sulfone-formaldehyde addition product. In some cases, the solvent system can be modified with methyl isopene derivative It is necessary to obtain this reac- geraniolfraktionen, which in the case of the fractionated distillation product to pyrolyze to obtain the sulfone ring lation, a noticeable sulfur odor split or crack and find the sulfur dioxide 40. This sulfur smell can come from the to drive out. The pyrolysis or cracking is easily carried out by products made according to the invention Heating of the sulfone reaction product achieved. Da- stirring with Raney nickel, preferably in one at, the reaction product is used to crack the amount of about 5 to 10 weight percent of the pro-sulfone to temperatures in the range of about 160 ducts. This treatment will heated to about 220 ° C. 45 preferably at temperatures in the range of about

Since methyl isogeraniol, the ester and the invention 20 to about 45 ° C and over a period of about

appropriate dioxane-reactive double bonds carried out Va up to about 2 hours, hold, the cracking is preferably carried out under conditions that the product is as short as

possible exposure to heat. Such an example common method for pyrolyzing the heterocyclic,

sulfur-containing ring consists in the sulfone- A mixture of 4.37 moles of myrcene sulfone and

Formaldehyde reaction product dropwise a 5.32 mole paraformaldehyde is added for 12 hours at a

Add liquid which is stirred at 50 ° C to pyrolysis temperature. The received 1305-g-

will hold, and the formed methylisogeraniol 55 crude product is added dropwise by the

condense vapors. Any non-reactive product to 300 g of mineral oil at one temperature

Liquid stable at the pyrolysis temperature of 200 ° C and a pressure of 10 to 20 mm Hg

can be used. In general it is usually cracked or pyrolyzed, and the evaporated pyrolysis

and economical, for this purpose a mineral oil to product is collected in a collecting vessel,

use. The product vapors are from the pyro- 60 The crude pyrolysis product is in an amount of

lysis collected in a collecting vessel. The capture 778 g is obtained and is released at a pressure of 1 mm Hg

Vessel preferably contains a protective agent in order to oxy- rapidly distilled, whereby 711 g of distillate are obtained

dation, isomerization or polymerization of the product. This distillate yields 271 g of light frac-

to prevent ducts. Suitable protective substances are hy- ions, followed by 237 g of methyl isogeranol fractions.

droquinone, 4,4'-methylene-bis- (2,6-di-t.-butylphenol), 6g The methyl isogeraniol obtained in this way is 50% pure, see above

Phenyl - /? - naphthylamine, 2,2'-methylene-bis- (4-methyl- that the total yield is 16.2% of theory.

6-t.-butylphenol), 4,4'-methylene-bis (2,6-di-t.-butyl- About 60 g of 4,4-dimethyl-5- (3-methylene-

phenol) or 4,4'-methylene-bis- (6-t.-butyl-o-cresol). 4-pentenyl) -m-dioxane obtained.

Claims (2)

Example II ^ ' ^e methyl isogeraniol product fractions analyzed, whereby at 0.8 mm Hg a bp - 80 ⁰ C, Myrcene sulfone in an amount of 4.37 mol is η = 1.4940, a UV absorption maximum with a stirred mixture of 5.32 mol Paraform- 224 πιμ and an extinction coefficient or ε value of aldehyde and 8.25 mol of 90% Formic acid added 5 of. 18 260 is found
set. Cooling devices are used to the reaction mixture at a temperature in Example IV to keep rich of 25 to 35 ⁰ C. After 9 hours it will the solution is supplied with the same volume of water. The procedure described in Example III provides thins, and the resulting lower layer will yield even better yields if the sulfuric acid is washed, until a neutral reaction is achieved. catalyst before pyrolysis or cracking of the The washed lower layer is then neutralized by sulfone ring with alkali,
dropwise addition in 500 g of mineral oil at a mixture of 4.13 mol of myrcene sulfone, Temperature of 180 ⁰ C and a pressure of 20 mm Hg 6.4 mol paraformaldehyde and 6.4 mol acetic acid cracked or pyrolyzed. The 621 g of the condensed anhydride is protected with uniform stirring at 50 vapors from the pyrolysis by adding up to 55 ° C a solution of 4.3 g of concentrated sulfur-30 g of 2,6-di-t.-butyl-p-cresol and then acid and 20 g of acetic anhydride in the course of 17 hours at 25 ° C with 800 ml ^ea hour ig added with a 10%. The reaction mixture is stirred with sodium hydroxide solution in order ^{to stir the ester at 50 to 55 0} C for a further 11 hours, then hydrolyze or saponify. The thus obtained ao 12 g of an aqueous 50% sodium hydroxide solution 571 g of hydrolysis products are added at a pressure of. 1 mm Hg rapidly distilled, with 472 g of distillate The acetic acid and the unreacted acetic acid hold which is fractionated to remove the methyl anhydride from the reaction mixture to obtain isogeraniol. Stripping removed in vacuo while the reac- The Methylisogeraniol thus obtained is 60% pure, 25 tion mixture at a temperature of 6O ⁰ C, or corresponding to a yield of 14.3% of theory. is held less. The reaction mixture will then slowly under vacuum to mineral oil at one Example III temperature of 160 to 180 ⁰ C given. That from the hot mineral oil distilling out methylisogera-acetic anhydride in an amount of 10.6 mol, 30 niolacetat is at temperatures in the range of 110 which contains 5 ml of concentrated sulfuric acid, to 130 ⁰ C at a rate of 14 to 30 ml of a mixture of 8.6 Moles of myrcene sulfone and distilled per hour and collected in a collecting vessel containing 10.6 moles of paraformaldehyde under constant rest an inhibitor. The acetate can be added. During the 1 hour addition of the fractional distillation and / or other anhydride-sulfuric acid mixture, the reac- 35 purification process is subjected to the mixture being cooled to the temperature in the range if desired, or if it is for a given rate of 25 to 40 ⁰ Hold C. After adding the turn it is necessary to obtain a higher purity anhydride-sulfuric acid mixture, the solution will be sufficient. The mixture was stirred for a further 48 hours at the reaction temperature. If the methyl isogeraniol has the desired end The mixture thus obtained is then dried at 50 ⁰ C and 40 represents product, the acetate is saponified by 2stündiges a pressure of 2 mm Hg to remove the acetic refluxing with aqueous-methanolic acid and unreacted acetic anhydride sodium hydroxide. The mixture is distilled. The 3380 g residue thus obtained are then cooled and the methanol is removed by distillation then by adding dropwise to 400 g of mineral oil. The organic layer is separated from that at 200 ^° C. and a pressure of 10 to 20 mm Hg in the aqueous layer with benzene and pyrolyzed with Na flow for 3Va hours. trium chloride solution until a neutral reaction Wash off the 2060 g of condensed vapors. Pyrolysis are 30 g of 2,6-di-t.-butyl-p-cresol as an anti-Then the benzene is stripped off, and it oxidizing agent is added and the mixture is obtained 581 g of 70% methyl isogeraniol, which hydrolyzes or saponifies in that it corresponds to a yield of 60% of theory for 17 hours with a yield of 60%. A solution of 400 g of sodium hydroxide in 400 ml of alcohol is then uniformly stirred from a mixture of the alcohol, water and 2.81 of methanol. with a polymerization inhibitor, calcium carbonate. After this time, the methanol is fractionally distilled from the and Raney nickel, the mixture being stripped in vacuo, and the hydrolyte-methylisogeraniol results in a purity of 82% 55 The fabric has a rig = 1.4928 and a density of reaction washed. The washed product becomes 0.9144 at 15 ° C. The methyl isogeraniol then rapidly distilled at 2 mm Hg pressure, giving a tart, fresh rose petal odor with muted 1283 g of crude product. Violet smell and is alone, in perfumes or others The crude product can be used on a 35.6 cm column of fragrance compositions,
fractionated with a reflux ratio of 4: 1, 60
wherein 701 g of methyl isogeraniol with a purity of 76% can be obtained, which is a yield of pure product corresponds to 37% of theory. A perceptible in the methyl isogeranol fractions 1. Process for the production of methyl isogera- The smell of sulfur is reduced by mixing the methyl 65 niol and its esters with a lower carbon isogeraniol acid with about 10 percent by volume Raney nickel, characterized in that at 45 ° C, stirring evenly for 1 hour, one Myrcensulfon with formaldehyde or a easily removed. Formaldehyde solution supplying compound in equi- 7 8 molar amounts, optionally in the presence of a sulfone and the formaldehyde in the presence lower carboxylic acid or its anhydride in the case of a mineral acid. Temperatures below about 90 ⁰ C converts and the third method according to claim 1 or 2, characterized obtained compound pyrolyzed at 160 to 220 ° C. characterized in that one is the implementation between 2. The method according to claim I ₉ characterized marked 5 the myrcene sulfone and the formaldehyde in one draws that the reaction of the myrcene temperature in the range of 25 to 40 ° C is carried out. 809 S68 / 576 6.68 © Bundesdruckerei Berlin