DE1618521A1 - Process for the isomerization of d-3-carene into d-4-carene - Google Patents

Description

PATENT LAWYERS

PATENTANWALT MÜLLER-BÖRNER PATENTANWALT DIPL.-ING. WEY

BERLIN 33 (DAHLEM) PODBIELSK.I ALLEE 68 8 MUNICH 22 WIOENMAYERSTRASSE

TELEPHONE 76 29 07 ■ TELEGRAMS: PROPINDUS TELEFON 22 55 85 ■ TELEGRAMS: PROPINDUS

19 837 Berlin, 30; June 1967

TIERCULES INCORPORATED, Yilmington, Delaware (USA)

Process for the isomerization of ά-3- ^ carene into d-4-caron

The invention relates to a method for the rearrangement of 5-carene in industrially valuable substances, especially the Rearrangement of 3-carene in 4-fermentation and the further conversion from 4-Ciren to useful p-monocyclic terpene clerlvates »

In particular, the invention relates to conversion from el — 3 — Careti in l — menthol,

The Carene comes naturally in numerous essential oils before, and one of them, the d-3-carene, is a major component of the turpentine, economically important Species of pine, which abound in turpentine containing d-3-carene, occur in all continents of the lielt in which pines grow, some particular species being P. Fonderosa in North America, P. Sylvestris in Europe and P. longifolia are in Asia.

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TELEPHONE: 018 4057

In the following description of the invention, the shorter and modern term "3- carene" is used instead of the older expression "Δ.-3-carene" and "4-carene" instead of '^ - ^ -.

The Carene adhere to the following structural formulas:

CH, ι J

H ₀ C

(la)

H-C:

HC

CH

CH _f

or

3-carene

(Ha)

HC

HC

CH ι

H, C C CH

³ I.

CH,

CH _f

CH,

or (Hh)

4-carene

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CH

H _p C CH
(Ilia) j Π or (nib)

CH

2-carene

Although most turpentines are useful solvents for fats, thinners for paints, detergents for
Brushes etc. are nowadays used in larger quantities of turpentine as starting materials for the extraction of other useful products
Chemicals used. For this, the turpentines are usually rectified by distillation, using concentrates
from individual terpenes such as X'-pinene and p-pinene. Z? -Pin is the most widely used substance for the manufacture of terpene resins. It is also thermally converted into myrcene and then into a number of fragrances and flavors, <? {- Pinene is a useful starting material for conversion to camphene and for hydrogenation to synthetic pine oils and mixed p-menthadiene hydrocarbons, which are the starting material for p-cymene
are. Ä-pinene can also be used for these purposes
Ornaments. However, it is usually much more expensive than
# -Pinene, so it is not usually used in cases where ^ -pinene achieves the same success.

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A review of the industrially important areas of application of the numerous terpene components shows that the Carene, especially the widespread d-3-Carene, are not able to displace one of the Pinene. This is because 3-carene does not polymerize to form hard, high-melting terpene resins; only oils are obtained The thermal isomerization also does not lead to myrcene or other acyclic compounds. The bad ones Hydrogenation processes successful with <* -pinene and ^ -pinene do not produce any significant amounts of synthetic pine oils when cooked. Until now neither could Catalysts still have conditions to be found by which 3-carene can be converted into camphene. Vigorous acid treatment converts 3-carene into a mixture of m- and p-menthadienes and viscous oils. When the m- and p-mentha— If dehydrated to cymene, they give mixed m- and p-cymene, which are difficult to separate and which are based on the Applications for pure p-cymene not yet can be used, in particular for the production of p-cresol and its derivatives. Because the Carene in general do not follow the reaction notes of the Pinene and are therefore not processed with the known methods their only important area of application is still the traditional ones of turpentine as a solvent for colors etc.

Although 3-carene as an industrial chemical starting material has not yet been as versatile as it is. how

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the Pinene, because its chemistry with that of the Pinene is not Has kept pace, it was found according to the invention that with the help of novel conversion methods it is called ohemi « shear raw material can be used, which leads to valuable products.

One aim of the invention is the conversion of 3-caitene into chemical substances that are more valuable than hydrocarbon solvents, (

Another goal is the conversion of 3-carene into p-menthadienes, which are largely free of m-menthadienes are.

Yet another goal is the conversion of 3-carene into p-cymene, which is largely free of m-cymene.

Another goal is the conversion of optically active 3-carene into optically active p-menthadiene,

Another goal is the conversion of optical active 3-carene in optically active p-menthenes,

Another goal is the conversion of 3-carene in 1-menthol.

Another goal is the conversion of 3-carene into hard terpene resins,

"6 ~ ·

Other objects of the invention will be apparent to those skilled in the art On the hand.

According to the invention it was found that (l) in the presence strong bases or (2) in the presence of a hydrogenation catalyst under hydrogen pressure 3-carene partially in its isomer, namely 4-carene, is rearranged. These partial rearrangement of 3-carene into 4-carene is one reversible reaction which leads to a mixture in which 3-carene and 4-carene are in equilibrium, with only There are traces of other components.

The partial rearrangement of 3-carene into 4-carene would be on not particularly useful because 4-carene as well as 3-Carene is known to be used only as a component of turpentine, which is a useful paint thinner etc. is. However, it became the additional finding made that 4-carene isomerized almost quantitatively to isolimones by heating, also known as 8,8-p-menthadiene is ticked,

Isolimons can be represented by the following foraol will

CH ₃ CH

^H P ^{G CH} ι ι

(IVa) ** (| f or | j (iVb)

H ₂ C CH
CH ^

Isolimones (2.8 ~ p-menthadiene)

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Isolimonen is suitable for further conversion to other useful substances, as described in more detail below is explained.

Isolimone is also valuable because it is following the method they previously used to convert other terpenes like polymerized to hard resins to a hard terpene resin (3-carene only gives oils), so that the present Invention shows a way how 3 — carene in hard terpene— resins can be converted. These hard terpene resins are useful ingredients for printing inks, protective coatings— Mixtures, adhesives, etc.

The isolimone obtained by thermal treatment of d-4-carene (made from d-3-carene) is da® d-tr & HS = -isomer _# This isomer is sterically related to the valuable 1-menthol.

d-trans Isoliraons

It is known (Pigulevslcy and Koshin, J. Gen, Chenw USSR Eng, TR 27, 879-90, ^{to which} reference is made) that d-trans-2-menthene by epoxidation and hydrogenation of

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Epoxides can be converted to 1-kenthol (plus carvoraentbol) can. According to the invention it was found that d-trans isolimones can be hydrogenated to d-trans-2-menthene with high selectivity under certain conditions. These Compound, d-trans-2-menthene, can be represented by the following formula:

CH,

.CH

I or (Vb)

CH

CH

, CH H ₃ C ^ CH ₃

d-trans-2-menthene

The method according to the invention for converting d-3-carene in d-trans isolimones and selective hydrogenation of d-trans isolimones in d-trans-2-menthene a means of transforming the hitherto almost worthless d-3-Carens in an economically important substance, namely 1-menthol, which is mostly still from foreign agricultural ones Sources. For the completion of the reduction of d-trans isolimones to d-trans-2-menthene can also not? cataly ti see procedures be used, as described in detail below and using the examples relating to this deduction will be explained in more detail «

• f

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load a source by the method according to the invention for d-trans isolimones and its partial reduction product d-trans-2-menthene will be used by the practicing organic chemist alongside the Pigulevsky process and Koshin, mentioned above, still other methods of converting the 2,3 double bond to given an eydrοxylgruppe in hand.

According to the invention, another way of converting d-trans isolimones into 1-menthol was found, that is consists that with the help of a strong base it becomes d-2,4 (8) -p-menthadiene isomerized, after which this carbon dioxide is converted to 1-menthol by known methods.

The compound d-2,4 (8) -p-menthadiene, which is used in the specialist literature also known as d-isoterpinolene, can by the following formula can be illustrated:

CH,
ι J
.CH

"CH

(VIa) ^A \ H or (VIb)

H ₂ C. J3H

ίί
C.

Η, ϋ

d-2,4 (8) -p-menthadiene (d-isοterpinolen)

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Known processes for the production of menthol from 2,4 (8) -p-menthadiene are up to the production of dl-menthol limited because so far the only i / economical usable form of 2,4 (8) -p-menthadiene the dl mixture

dwar (mixture of 72.4 (8) -p-menthadiene and l-3.4 (8) -p-menthadiene), which can be obtained by acid treatment of certain terpenes. Patent 2,851,481 describes a method after which the hydrochloride of 2,4 (8) -p-menthadiene mainly is hydrolyzed to dl ~ 3-menthen-8-ol, which in turn is converted back into dl-pulegol and this to dl-menthol isomers can be hydrogenated. Patent 2,366 describes a process by which dl-2,4 (8) -p-ifenthadiene is partially hydrogenated to dl-3-menthene and the latter over </ - Glycol and ketone is converted to dl-menthol. By doing In these processes, if dl-2,4 (8) -p-menthadiene is assumed, they can only lead to dl-menthol, which is a commodity contains only a small amount of 1-menthol, so that it can usually only be used in such cases where the full cooling effect of 1-menthol is not required. Reference is made to patents 2,851,481 and 2,866,826 referenced.

The present invention becomes d-2,4 (8) -p-menthadiene available for the first time from the cheap terpene d-3-carene, which, from the point of view of experts in the field, is only used as a solvent, and it allows the application of the known methods which are based on the treatment of dl-2,4 (8) -p-menthadiene

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the production of 1-menthol, Jie will be explained below, can also non-Iratalytische methods are applied for completion of the conversion of d-trans-Isoliinonen to a-2,4 (8) -p-menthadiene.

The first stage in the extraction of the aforementioned group of related useful substances from d-3-carene! Consists in the rearrangement of d-3-carene in d-4 cooking with the help of a Catalyst. According to the invention found that suitable catalysts consist of a group of start 3ase.n, which are used under I? edbedingungen in which the Carl anions of a hydrocarbon are formed, and that they are also from a group of hydrogenation srcataly— in the presence of "ihydrogen with an over Afciaosphärendruclr lying bridge exist ».

The ex'ste group of catalysts consisting essentially of simple or complex Al'talimetalialxylen including acyclic, cyclic and aromatic .'ü-'ra.li ~ cietallderivcten and strong 3asen i;.? Alkali IE '- iallal-ro ^ olaten and Allcali ^ etallaniid-en, the expedient in the media vcr ^ s where their basicity may develop, Ox3ce y.lkalime tall soft ^J a sufficient basisoi "uIp training Car'.aniouen of hydrocarbons in the presence of dip ^^ rroi »aprotic LOSUnSr ¹¹ IIt ⁺ ^ ¹¹ P v: ± o " Diniethylsulfo i; I to be indexed, but not in "oolar liydro..ylisehen L'5s""liquids such as alcohols, the alkali metal amides are e ^ en all sufficient basisoi,

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to cause the formation of carbanions if the medium is an amine or a hydrocarbon, but not if the medium is an alcohol «

It is of course appropriate to use a hydrocarbon as the medium in particular, the use of d-3 cooking itself is expedient both d-3-oarene and the strong base under conditions in which they mutually dissolve, and so the reaction is at least partially homogeneous. Under different conditions the strong base is largely insoluble in the d-3-carene-containing phase and the reaction is essentially heterogeneous and takes place on the surface of the basic catalyst.

Organic compounds that work with alkali metals like Li, Na, K, Rb and Cs to form strongly basic catalysts for use in the method of the invention Compounds or form complexes are hydrocarbons such as olefins, cyclic olefins, aromatic hydrocarbons including polycyclic aromatic and aralyryl hydrocarbons and acetylene hydrocarbons, as well as heterocyclic compounds related to hydrocarbons in which one or more carbon atoms are replaced by nitrogen or other heteroatoms, such as pyridine, alkylpyridine, quinoline, pyrrole and Dibenzofurans

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In some cases, sodium or other alkali metals react easily with the organic compounds mentioned. In other cases the reaction is so slow that it appears desirable to use an "accelerator" or "Initiator" used to initiate the conversion between sodium and to accelerate the organic compound ,, Such "accelerators" or "initiators" can be halogenated organic compounds that react readily with sodium, such as o-chlorotoluene, as well as others Metal alkyls including the previously formed alkali metal derivatives of a hydrocarbon or a related substance. In industrial practice it may be desirable to have a small amount of an old one, but still use active catalyst to initiate or accelerate the reaction between sodium and a To support hydrocarbon, for example to a to form new catalyst. Catalysts such as the alkali metal derivatives of alcohols and amines can usually can be prepared by direct reaction of the alkali metals with the alcohol or amine, even without the addition of a Initiator expires willingly enough.

Depending on the system chosen, the strongly basic catalyst can be formed and danti with the too isomerizing cooking, but it can also Formed in situ, metallic sodium, which with o-chlorotoluene or with other halogen compounds

is accelerated, as described by duroh Pines and employees (cf. J.A.CeS. 77, 6314 (1955); J.A.C.S. 78, 1178 (1956) and Paten * 2 804 489), is a suitable and cheap strong base, Other representative suitable bases are the sodium derivatives of methylnaphthalene in methylnaphthalene, the sodium and / or aluminum derivatives of ^ -picoline in ^ -Pikolin, potassium tert-butoxide in Dime t Jay isulf oxide, Lithium in ethylenediamine, amyl sodium in hydrocarbons and the like. In general, any base can be used in the context of the invention, which under the prevailing conditions is strong enough to form carbanions, and the examples are merely representative ways of carrying it out show the method according to the invention are not intended to limit the invention in any way, as with the same success aucfyandere and equivalent combinations of strong bases, temperature, time and medium can be applied.

In general, the appropriate relationships between time, temperature and the amount or activity of the catalyst will depend on the particular case at hand. The appropriate temperature range is zwisohen room temperature and 180 C. The lower temperature limit is determined by the fact that at a far below room temperature temperature, the reaction proceeds too slowly, nut if not the ratio of catalyst to cooking is particularly high. The thermal isomerization of 4-carene is above 180 ° C

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to isolimones represents a strongly increasing side reaction. In In the presence of the base, the isolimone is converted to 2,4 (8) -p-menthadiene «The formation of small amounts of m- and p-cymene is another side reaction that occurs with increased Temperature takes place «That is why the appropriate temperature range from tree temperature to 180 ° C is not to be understood as restrictive because it is exceeded or not reached can be achieved if the described effects are desired, If the catalyst system is chosen so that the isomerization runs rapidly at 180 ° C or above, it is quite possible to reduce the time at such a temperature so that side reactions are suppressed to a great extent and the treatment result largely depends on the isomerization remains restricted from d-3-carene to d ~ 4-carene.

The isomerization of d-3-carene to d-4-carene is a reversible reaction that eventually reaches equilibrium. The maximum amount of d-4-carene in this equilibrium mixture is about 45% by weight. It is of course not necessary to drive the isomerization to the point of equilibrium, the 4-Oarene has a lower boiling point than the 3-Carene, and the isomerization can be stopped at any point and a- Remove ^ Carene-Konze ^ occurred by fractional distillation. Because d - ': - cooking has a lower temperature, one method of operation is that d-3-carene and the catalyst (possibly together with one for the

BAD OR | Q / m _al

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Medium suitable for the catalyst) into a catalyst chamber, which can be the still of a distillation plant, or in a chamber which is in a still leads, and that the overflowing from the distillation, d-4-carene-containing product is eliminated.

For the conversion of d-4-carene into d-trans isolimones is it is not necessary to separate the carenes from one another. According to the invention it was found that when a mixture of d-3-carene and d-4-carene is heated to a temperature necessary for the isomerization of d-4-carene to d-trans isolimones is sufficient that the d-3-carene remains largely unchanged and easily by fractional distillation from which d-trans isolimones can be separated. The high thermal stability of d-3-carene is in the Literature noted (Beilstein EIII, Volume 5, page 363), where d-3-carene is referred to as stable up to at least 400 ° C will. Suitable heating times for the largely complete conversion of d-4-carene into d-trans isolimones are 16 hours at 200 ° C, 3.25 hours at 220 ° C, 43 minutes at 240 ° C and 11 minutes at 26o ° C. It can even higher temperatures can be used with a correspondingly shorter time, because both d-trane isolimons as well as d-3-carene have good heat stability «

The heat-treated Gemisoh is in a Püllkörperfraktionier column or suitably rectified in a series of continuously successive fractionation columns, where d-trans isoliroones as technically pure, bright

Fraction is separated. 209824/0998

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The concentrated d-3-carene is initially volatile Substance that is also obtained as a technically pure substance is and the stage for isomerization to d-4-carene again can be fed.

Tienn the hasic isomerization of d-3-carene to d-4-carene is undertaken under conditions in which side reactions are significant, the resulting appear Products as an even higher boiling substance, mainly m- and p-cymene and d-2,4 (8) -p-menthadiene contains. These substances are considered higher boiling points from the system Distillation fraction or removed as a bottom product and not returned to the cycle for their degradation to avoid.

Because of the close boiling points of d-trans isolimones and d-3-carene must be used for this separation an efficient column can be used when high purity d-trans isolimone is desired. At work in the laboratory it was found that with a packed column of 1 »diameter that was 10 feet high with interlocking Packing was filled, a very satisfactory separation could be brought about.

The production of d-trans isolimones from d-3-carene can be carried out in a continuous process. This is that d-3-carene in a continuous

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Treatment stage is catalytically isomerized to a mixture with the desired amount of d-4-carene. This The mixture is then separated from the catalyst by filtration, decantation, distillation or the like and continuously with one sufficient for the largely complete conversion of the d-4-carene into d-trans isolimones Heat treated for temperature and time. The d-trans isolimone is produced as a process product, for example by distillation separated off and the d-3-carene fed back to the catalytic isomerization stage.

A suitable precipitation column (e.g., the one above described) separates the by-products into two fractions, namely (l) mixed m- and p-cymene, the are suitable as solvents, and (2) d-2,4- (8) -p-menthadiene, the known process in 1-menthol or » can be converted into pure p-cymene.

The isomerization of d-3-carene into d-4-carene can take place under Use of a hydrogenation catalyst can be carried out in the presence of a limited amount of hydrogen. It is useful if the pressure is above atmospheric pressure 1 / hydrogen pressure to work. According to the invention found that when using a 1 / hydrogen pressure slightly above atmospheric pressure with a palladium catalyst from d-3-carene d-4-carene is formed, and that the formation auoh duroh a Niokelkatalysator at low Temperatures like room temperature and by one

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Copper Chromite Catalyst Catalyzed under vigorous conditions will. Appropriate conditions for copper chromite are a hydrogen pressure of 50 to 100 p.s.i.g. and 150 to 170 ° C. This is due to the lower activity of copper chromite compared to Pd and Ni catalysts, which the latter at room temperature and a liasserstoffdruc'ic from 50 p.s.i.g. and are less active. From this point of view of the invention, the most appropriate one is .Working range between room temperature (about 23 C) and 180 C and the pressure at an animal above atmospheric pressure to about 100 p.s.i.g. A secondary reaction which consists essentially in the hydrogenation of the double bond of the d-3-carene occurs under all conditions, and so caran and / or other hydrogenation products are formed as by-products when used to isomerize d-3-carene to 4-carene a hydrogenation catalyst plus Hydrogen is used. Under different conditions, the carene can form menthane and trimethylcycloheptane as well as being hydrogenated to caran. In general, can these substances in the production of d-trans isolimones thermal isomerization of d-4-carene and further boi the Umwaiidlung to, for example! -Menthol run along Because they are saturated, they are largely inert. At a point where it seems convenient, they can desired? be removed in 1 s. They are useful Solvent, and Carnn can be treated with acid,

where ίϊΙ.-3-menthene arises, which, as in the patent 2,846,486 is an intermediate for the

Extraction of dl-menthol is.

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To the formation of these saturated hydrocarbon by-products to a minimum, it is desirable to to keep the pressure as low as possible if more active catalysts are used. Since it is in is generally simple, the formation of d-4-carene by Following infrared spectrophotometry or gas chromatography, the cooking-catalyst mixture is in the appropriate Measure with hydrogen at a slightly above atmospheric pressure pressure is brought into contact, and this pressure is increased in small steps until a sufficient isomerism ratio what is indicated by samples to be taken for analysis has been achieved, Venn copper chromite or a similarly weakly active catalyst is used, the Carene Katalyeator Gemlsch is expediently under one Hydrogen pressure from 50 to 100 p.s.i.g. kept, and the Temperature is increased in small steps until the sample is taken shows that d-4 ~ carene is formed in a useful ratio. Higher pressures can also be used, for example 500 p, fl, i «g., with a very low Change in the formation of by-products because these catalysts generally have a relatively low ability to Hydrogenation of carbon-carbon double bonds exhibit. However, since a high-pressure system in general is more expensive than a low pressure system, it is usually appropriate to operate at low pressure.

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How this can be a hydrogenation catalyst Isomerisierungsgemisoh obtained are continuously prepared using, for example, by fresh and / or recovered d ~ 3 "Caren is pumped _t when using a strongly basic catalyst by separated a Iaomerisatstrom continuously from the Behändlungsstufe, for example by filtration or evaporation, is by passing this stream to a thermal isomerization vessel, where it is maintained at a sufficient temperature for a time sufficient to isomerize d-4-carene to d-trans-isolimones, and by transferring the product leaving the thermal isomerization stage to a continuous distillation unit. tion stage is passed, where the dr-trans isolimone is separated, the d-3-carene precession is returned to the cycle. and by-products are removed,

Some attention should be paid to the impurities in the starting material d-3-carene apply if this is catalytically rearranged to d-4-carene, as described above, d-3-Carene avidly absorbs atmospheric oxygen and thereby forms Osydatiotis products. In catalytic isomerization with a strong base, in which the active base is present as an insoluble phase and the isomerization in the usually takes place on the surface of the base is it is appropriate when the carene is freed from impurities that could coat the active surface. in the In general, these substances (for example oxidation products) are polar and usually contain hydroxyl groups. she

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can be removed by adding the carene over sodium is distilled, or by adsorption with activated clay or other adsorbents, in order to renew Formation of oxidation products in the so purified To prevent Carene, this should be kept in the absence of air. «The strongly basic catalysts themselves react with air and moisture and thereby become destroyed, so that it is generally desirable to use the Catalyst and the introduced carene before these decomposing To preserve influences. Take appropriate precautionary measures an activated sodium- catalytic converters have a very long service life. In the case of the batch method, for example using a Ratio of 1 part by weight of activated sodium per 100 parts by weight of purified carene, the catalyst can be separated from the carene and at least half a dozen times to be reused, so that eventually at least 600 parts of d-3-carene isomerized with 1 part of sodium to give d-4-carene can be.

Of course, the catalytic converter will wear out a bit, in part due to the impurities, which preferentially combine with the catalyst and thus for the isomerization unusable, and partly through mechanical loss due to fine particles, if for the separation of the isomeric ized Carens decanted from the insoluble catalyst will. In the case of the ilochet temperature process, at least sioh

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but slowly an active catalyst by bringing them together of sodium metal with the reaction mixture, the nature of the formation of the active catalyst is not clear, and they can be made by reacting sodium with a small amount of it aromatic hydrocarbons (cymene), which are accelerated as by-products in the high-temperature process are present, or with "to be added" appropriately to be selected Aromatics. In any case, the catalyst bed wiid by the addition of a little fresh sodium from time Time to compensate for losses due to contamination and mechanical losses kept in an active condition «

When a hydrogenation catalyst is used, the common hydrogenation catalyst poisons become important »When that Cooking comes from sulphate turpentine, so take care of it carried so that the sulfur level is low, hydrogenation catalysts however, are not particularly sensitive to small amounts of air oxidation products Cooking, such as cooking obtained through the ordinary careful processing. In general copper chromite and related catalysts are less sensitive to traces of catalyst compounds as Nickel or palladium, and because of this, they can be particularly attractive.

Des nac! = Obtained by the method described above d — trans-Isol ^^^ nen, "das rIb p- ^ Ienthadien i ^ t, can ä'irch be ': 2 "nth process for converting ρ-McTi + h-i-dienes into

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p-Oymol can be converted into this. It can also be polymerized to ^u frten terpene resins. Kx uev " os it is desirable to use it for the conversion to 1-mentliol nao ¹ · ^r Ic« i method of Pigulevs!: Yi: ri tCgrMk or according to other methods in which of d-trane-S-Meiitl-en It is assumed that it is advisable to hydrogenate the exocyclisobic double bond selectively.It is clear that the possible hydrogenation products of d-trans isolimones

d-trans isolimones

the following connections are:

d-trans-2-menthene

trans-8 menthene

trans-p-menthane

According to the invention it has been found that although nickel and palladium give all of these hydrogenation products in a more or less random manner (cobalt acts similarly), platinum particularly favors the selective formation of d-trans-P-menthene and that ruthenium is technically sufficient

BATH ORIGINAL

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Has selectivity, a crude product with about 80 fo cf-trans-2-menthene is obtained, which is mainly supplemented by trans-p-menthane and contains no trans-8-menthene * The selectivity of platinum is improved by reducing the catalyst concentration to almost the point of disappearance and by reusing the catalyst. Under optimal ¹ conditions, this catalyst can achieve the performance of ruthenium; on the other hand, in addition to the favored 2-menthene, this generates sensitive amounts of trans-8-menthene and of course p-menthane, but if d-trans isolimones under preferred conditions lead to d-trane- 2-menthene is hydrogenated, the crude product contains about 80% by weight of d-trans-2-menthene and negligible amounts of trans-8-menthene, which is mainly supplemented by trans-p-menthene and little unreacted d-trans-isolimone will »This Gemiseh [can be used for the conversion to 1-menthol by the method of Pigulevsky and Eöshin and by other means. Appropriate hydrogenation conditions mean a minimum amount of catalyst, preferably 1% by weight or less, the use of Pt or Ru, a temperature of about 0 to 100 ° C. and a pressure between atmospheric pressure and 100 p, s, i, g, if necessary higher pressures or other catalysts such as Ni, Pd or Co can also be used. At the upper temperature limit the isolimon disproportionates,

Through direct chemical processes, d-trans isolimones can be produced can also be reduced to d-trans-2-menthene. The addition of

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Hydrogen halides such as hydrogen chloride or hydrogen bromide selectively attack the exocyclic double bond first on, with 8-halo-2-menthene being obtained in almost quantitative yield. The halogen can for example by Reduction with sodium and alcohol or other combinations of metal and active hydrogen are selectively removed, whereby d-trans-2-menthene is formed.

Alternatively, d-trans isolimone can be converted to its aluminum derivative, such as by heating with triisobutyl aluminum. The aluminum compound is formed preferentially at the terminal double bond. Decomposition with water or other active hydrogen compounds leads to d-trans-2-menthene plus aluminum hydroxide »The reduction the terminal double bond is quantitative,

d-trans isolimones can also lead to d-2,4 (S) -p-menthadiene being transformed. The d-2,4 (8) -p-menthadiene can then if desired, converted to 1-menthol in accordance with the teaching of patents 2,851,481 and 2,866,926.

For the conversion of d-trans isolimones into d-2,4 (8) -p-mentha ~ serve under conditions of temperature, time and base concentration suitable for carrying out the isomerization the isolimonen is brought together with a strong base. With a potassium tert-butoxide / dimethylsulfo ^ id system the isomerization proceeds almost instantaneously (and

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BATH ORIGINAL

exothermic) at room temperature, a side reaction occurs on when d-3-carene for isomerization to d - ^ - cooking with

ο an active sodium catalyst heated at 170 to 180 C. will. At this temperature, d-4-carene slowly isomerizes thermally to d-trans isolimones, which is the basic one Catalyst converts to d-Sj'iisl-p-menthadiene »The activated Pine S-Type Sodium Catalyst (described above) causes the further conversion of d ~ 2, A (8) -p-menthadiene to other products only slowly ^ but catalyze other strong bases this further conversion very quickly.

The next isomerization proceeds on the ring diene, which ultimately "borrowed leads to an equilibrium, the fo about 50 $ e / terpinene, 20 ⁶ J ₀ y'-terpinene, 25 fo 2.4 {8) -p-menthadiene and 5 Contains 3,8-p-menthadiene. It is known that the ring dienes dehydrate to p-gymol if this isomerization is carried out at a sufficiently high temperature. Therefore, in the case of a particularly strongly basic catalyst, the time and temperature should be selected appropriately in order to carry out the desired isomerization in a reasonable time, and the reaction should be interrupted to allow the further conversion of the desired d-2, * t (8) - Avoid p-menthadiens' in une rw ims elite products. The same types of catalyst as are used for the isomerization of d-3-carene to d-4-carene are suitable for this purpose. The conversion can easily be followed by infrared spectrometry, gas chromatography or ultraviolet spectrometry

209824/0998

- "β -

■ - 28 ~

will. Suitable working conditions vary between room temperature or below (potassium tert-butoxide-dimethyl sulfoxide system) up to reflux temperature with activated sodium catalysts of the Pines type.

d-trans isolimones can also be converted to d-2,4 (8) -p ~ menthadiene by non-catalytic processes. For this purpose, for example, one mole of HCl is added to d-trans isolimones, with 8-chloro-2-menthene monolydrochloride being obtained in almost quantitative yield. By refluxing this substance with bases such as pyridine or alcoholic potassium hydroxide solution, it is largely converted into d-2, ^/ t (8) -p-menthadiene.

The following are used to explain the invention in more detail Examples in which, unless otherwise specified, parts and percentages are parts by weight and percentages by weight mean,

example 1

A flask equipped with a Hochleistungsrührerex Reaktionsko? Was bon with a Stiokstoffeinleitung, an outlet, a thermometer and a Infr ° red ^T iei? 3 ampe provided "In these were under a nitrogen atmosphere 500 g of dry xylene (mixed isomers) and placed 10 g frischgesohnittenes sodium. The flask was heated to melt the sodium with the infrared lamp at 100 C, the ^"wimuch: i watch it in operation set was NaCl · wen {ton r.jhmtrn.!

BATH ORIGINAL ->>> -

20 982 4/0998

While stirring vigorously, the heat lamp was turned off and the mixture was allowed to cool to 70 ° C. with continued stirring to keep the sodium in dispersion during the solidification. The stirrer was then switched off and the mixture was allowed to cool for 2 1/2 hours and allow it to settle. 250 oom xylene were then pipetted off from the mixture, very little sodium being entrained. The remaining suspension in the flask was treated with 250 com d-3-carene (95 io purity, determined by Gasohromatographie), which had been distilled over sodium and stored under nitrogen * To the mixture was entnom- a sample. which served as a reference substance for the infrared spectrograph, after which the mixture was stirred at 65 ° C for one hour and a sample was taken again 10 cc o ^ Ghlortöluo} offset the temperature woduroh rapidly to 82 ° 0 increase "A Stumi · naoh the addition of the o-Ghlortöluols! showed © ine infrarotepektrometriecli tested sample _# that the formation of d-% ~ Caren had used was Stirred for a further 3 1/2 hours, and then a further sample was examined. "About 30 % of the d-3". Car "n" had been rearranged in d ** 4-0arett.

Example 2

In a 2 liter Kolbeii equipped with a stirrer 600 g of xylene (mixed isomers) introduced, of which 100 g were distilled off to ensure dryness. The condenser was then brought to reflux and 10 g Freshly peeled sodium was added, whereby for

Dispersion of the sodium under the semisch a few minutes Was refluxed and stirred under a stream of nitrogen. This The mixture, which is stirred under reflux, is carried out by means of a dropping trioether mixed with 10 oom o-chlorotoluene. The mixture was then under nitrogen flow to form the active The catalyst was stirred under reflux overnight.

The following morning, after cooling, 500 g of d-3-carene were obtained (95 # purity, distilled over sodium and stored under nitrogen) was added. The mixture was then under The stirring was heated to reflux and samples were taken every hour for infrared analysis. This became the following Receive work protocol:

Remarks

Start of warming

Reflux

Sample 1 (8 % d-4-carene)

Sample 2 (24 # d-4-Car ”) Sample 3 (38 % d-4 ~ Gar” n) Sample 4 (42 % d-4-Car ”n) Sample 5 (42% d-4-Car” n)

time Temperature ⁰ C 08.45 32 09.30 151 10.30 153 11.30 153 12.30 153 13 * 10 152 14.30 152

Infrared analysis indicated an hourly increase d-4- "Carene up to the fourth hour" Sample 5 showed none further increase in d-4-carene »

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209824/0998

Example 3

Here the isomerization of d-3-carene was carried out in that the active sodium catalyst was formed in situ by 3 l of a mixture of d-3-carene (95 fo) , which had previously been distilled over sodium, and xylene in the Ratio of 50:50, 10 g of sodium metal and 10 ecm of o-clilortoluene were stirred under reflux. Stirring at reflux was continued until infrared inspection of a sample indicated equilibrium was reached. The mixture was then cooled and the catalyst allowed to settle. The carene / xylene mixture was then decanted off and replaced by k ± hk 2 liters of fresh cooking alone (without xylene), which had been distilled over sodium. The mixture was again stirred under reflux until infrared analysis indicated that equilibrium had been reached. The carene was decanted again and replaced with fresh carene distilled over sodium. This procedure was repeated until a total of six passes had been carried out over the same catalyst bed using the total amount of carene. As a result of the large number of passes, the procedure was simplified in that the mixture was only stirred under reflux overnight and tested the following morning to make sure of isomerization. Under these conditions, the reflux takes place at 170 to 175 ° C. Several by-products were formed. The gas chromatographic analysis of the six runs using pure d-3-carene with one and the same catalyst bed gave the following results:

209824/0998 '= "■

Component no.

traces

1.1

0.2

35.1 47.0

1.6 o »3

7.3

6 * 6

0.5

Identity

Not identified Not identified fi-Careii

Not identified d-4 «* CJaren

d-3 ^ C are ti

Bipenten

Not identified ole and p-cytnol d-2,4 (8) * »p-> metithadles Nlttht. identified

It was found that the ratio of d «4-Gareu to d-3-Carene was about 43:57 »

After completing this sieve, the catalyst bed was replaced j?; bäekantierön von de «i last cooking under Stiokstoxf three Stored months * oils reuse (after the same Process) showed that the catalyst was less active, but still active "By adding 10 g of fresh Sodium (but without o-chlorotoluene) was the activity revived. Usually there were three more Runs carried out and the catalyst bed stored under nitrogen *

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W8521

When the isomerization of d-3-carene was carried out at about 150 ° C. under reflux and drilling in the presence of toluene or xylene in order to keep the boiling point at this temperature, the formation of lifting products was almost completely suppressed. Other di ^ ge xvars are of course pale; 150 C slightly lower than at 170 C> The gssorromatogra- phical Anat ^ se cJes product of the reaction in toluene gave (on tcUioifreier basis) 35.5 $ d-4-carene, 59.5 $ d ~ 3-Carctt, 5 / j other substances (emanated from ro ^ 05 ^ igem dt — 3- »carene) ♦

example H

Most of the cooking with approximate equilibrium obtained according to Example 2 was, after decanting off the catalyst, filtered through a folded paper filter and placed in portions of 1500 ecm in a stainless 2 l Parrautoclave. Each batch was heated to 220 ° C., held at ~ 20 ° C. for four hours and then cooled. At 220 ° C., a pressure of about 40 psi, g developed. however, the d-4 ~ carene-iJamien, do.ß ': an α-4-carene left over ./ar »Instead, the rjamien of d-trans isolimons came in." »The d-3-carene content showed a negligibly small change, the d-fcrans- * isolimonen was separated by fractional distillation in an almost crude form and had the following physical effects:

Mp 1.4636

d ₂₅ 0.8230

d ^ (10 em-Neat tube) + 167 °

Purity by GC 99 fo

Example 5

A portion of the cooking in equilibrium described in Example 3 is used to separate the d-4-carene from the d-3-carene in a 1 "10'-acid which is ^{filled with 0.16 H} interlocking packings; ar, fractionally distilled at a working pressure of? 5 Torr and a reflux ratio of iO: 1. The separation of d-4-carene is less sharp than the separation of the d-trans isolimony from d-3-carene, but less sharp Obtain d-4-carene with the following properties:

N ^ ⁵ 1.473

d ₂₅ 0.856

em-Neatrohr) +76.3

+89.1

MJ

UV (methanol) ^ max ~ ^2l ^ purity by GC 94 %

Example 6

d-trans- Iaolimonen geniiii Example 4 was made with a Ilutheniiua catalyst as it is hydrogenated: in a par-

BATH ORIGINAL

Soliüttelf flap 16 g of d-trans-Isolimonen, lh g of isopropanol and 0.16 g of commercially available Rutheniura charcoal Xatalysator introduced. The initial pressure was 50 ps, "g" Until a heating lamp was switched on to warm the bottle, "no" hydrogen was adsorbed. After that, hydrogen adsorption began over a period of two hours the shaker was stopped. Do Abfil "** trate the catalyst and the isopropanol Eerauswasehen with ¥ ater the Produlct was infrarotspektroaetrisch and gaschromatographiseh examined" the {JaschröHiatograram yielded 7.4 $ trans-p-menthane _f 75 "^ f ° d-trans -2-menthene _r 11.5 ¹ Jo unreacted d-trans-isolimonen and negligible your amounts of tran-s—

In game 6

In a more alternative experiment, a ruthenium catalyst was shaken in isopropanol at 50 psig using a heat lamp to preactivate it. The catalyst was then separated off by filtration and placed in the Parr shaker along with Ik g isolimones. The hydrogenation was interrupted after the reservoir pressure had dropped to 8 psig (approximately equivalent to the theoretical amount of hydrogen). The gaschromatographisohe analysis showed 15.2 fo trans-p-Mentlian, 78 fo d-trans-2-lientheu, 5, * "h ^ d-trans Isoliiaonen and a small amount of other compounds. 8-Henthen .erden could not detected .

^BA 0 OR _{! GmAI} " ⁵⁶ ""

209824/0998

Example 7

The following materials were In one with a stirrer, one Gas inlet tube, a thermometer and a nitrogen inlet and outlet provided 5 l flask

750 ecm d-trans isolations 3000 com isopropanol 0.5 g Pt oxide catalyst

Hydrogen was introduced through the inlet tube (The temperature was kept at 30 ° C ί 2 ° C), and samples were taken periodically for infrared investigation. Each sample was soaked in water and the oil layer was washed and dried. The refractive index was also measured. As the infrared spectrum »an essential one Decrease in methylene endgroup hands was demonstrated the gas chromatography analysis was also carried out. No gas chromatography was performed on the first three samples Analyzes made.

sample

Component no,

4th 5 6th identity 0.7? % 0.4 % 0.6 % Not identified 9.2 16.6 19.4 trans-p-menthane 1.1 0.6 1.4 Not identified 62.2 67.6 68.7 d-trans-2-menthene 6.0 4.8 2.0 trans-8 menthene - 0.4 0.6 Not identified 16.1 2.4 0.9 d-trans «-Isolimones 1.1 1.3 1.5 Not identified 0.4 - - Not identified 3.4 5.9 4.9 Not identified 1.45K 0 1.4479 1.4475 4/09 9a

1610521

Example 7a

The selectivity of a Pt catalyst was improved by the following procedure: 15 g of d-trans isolimones and 0.075 g of Pt oxide catalyst were placed in a Parr ^ shaker bottle. The hydrogenation, which began at an initial hydrogen pressure of 50 p, si, g «, was stopped after 40 minutes after approximately the theoretical amount of hydrogen had been adsorbed. The contents of the bottle were poured out, and the analysis showed insufficient selectivity. 15 g of fresh d-trans isolimone were placed in the bottle that had not been worn out, but without a catalyst d-trans ^ isolimones absorbed about the theoretical amount of hydrogen, and the Sohtittler was stopped 20 minutes later. The gas-chromatographic analysis showed 15.2 $ trans-p-menthane, 78.0 # d-trans-2-menthene, 5, ^ for d-trans-isolimones, no S-menthene and best small amounts of impurities,

This procedure with only traces of Pt catalyst was extended in the following way and introduced 0.25 g of Pt oxide catalyst. The Anfangsvnnferstoffdruok was 100 p »s _o i, g" The hydrogenation was continued at tree temperature (maintained by the KÜhlsohlange) * "is about the theoretical hydrogen was added quantity. The gas-chromatographic

BAD ORJGJNAL -

" ³⁸ "

Analysis of the product showed 13.8 # trans ^ p-methane, 78.1 $ d-trans ~ 2-menthene, 6.9 $ unreacted d-trans-isolimone, no 8-menthene and 1.3 # impurities,

After filtering off the catalyst, the ^ w * was "impure d-trans-2-menthene without further treatment by the method of Pigulevsky Eoshin and converted in good yield in 1-menthol.

Example 8

In each of these experiments, 16 g of d-trans isolimones were diluted with Tk g of isopropanol and hydrogenated in a Parr-Sohüttler with the designated catalyst at room temperature until about the theoretical amount of hydrogen was absorbed, as was determined by the drop in the container pressure. The initial hydrogen pressure was 50 paig. After removal of the catalyst by filtration and the isopropanol by washing with water, the hydrogenation product was examined by infrared spectrometry. The catalysts used were Raney nickel, Raney cobalt and commercially available 5 follow Pd-carbon. The infrared spectrograms of these experiments showed less d-trans-2-menthene than had been obtained with the Pt or the ruthenium catalyst, and the presence of old 8-menthene. The product obtained with the Raney cobalt was examined by gas chromatography, with 19.1 % trans-p-menthene, 58.4t ^ d-trans-2-menthene, 16.4 % trans-8-menthene, 2.4 % d-trans-isolimones

- 39 -

were found. The one using Pd and Ni
products obtained differed somewhat in terms of distribution
from the "lianey cobalt"

A Raney Niokel catalyst moistened with water sometimes shows an increased selectivity «By shaking iron
16 g isolimones with a Raney nickel catalyst moistened with barrels at room temperature, an initial pressure of
50 psig and a reaction time of three hours, however, a product was obtained which, as determined by gas chromatographic analysis, toe ¹ «! © ,, 13.0 # trans * -p-menthane, 48.6 # d-trans-2-menthene , 18 "contained 7 % trans-8-menthene and 16.8 fa d-trans-isoli &oaen"

Because träns-8-menthen in about the same degree
2-menthene reacts with peracids ₉ wait of
Peracids useless _s consumed when at üem "- there are menthol method of Pigulevsky and Koshin and other processes in a mixture with 2-menthene!. Through his education
Not only is the initial isolimon attacked, but it also interferes with the following stages.

Example 9

25 ecm of a sample of pure d-3-carene became 110 ecm Dimethyl sulfide dried with molecular sieves and 9.0 g Potassium tert-butoxide added. The mixture was 23 hours

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209824/0998

stirred at 65 ° C. The mixture was then poured into water and the oil was extracted with hexane. The hexane solution was washed while the hexane was distilled off. The gas chromatographic analyzes showed two peaks, one of 40.7 # and another of 59.3 % The first peak corresponds to d-4-Garen and the second d-3-Carene,

The heaktion was made by using 253 com 95 d-3-

/ Cären (the impurities were different Terpentinkomponenten) but not 4-carene), 1112 g and 91 g Dlaethylsulfoxid Kaiium-tert, butoxide expanded "The Bohprodukt gave after de" washing .in the gasohromatographisehen analysis 37% ~ 4-cooking, 58.4 # d-3-carene and 4.5 # other constituents «The crude product was fractionated in a laboratory distillation unit with a 1» χ 48 " ^{column which was filled with 0.16 n} interlocking packings« There was none achieved sharp separation between the Carenen (the column is for this Zweoke too short), but the lower boiling was enriched d-4 ~ Caren in the first fraction, "Sine sample with 56.0 fi d-4-carene, substantially by ö-3-carene was added, was used for Ieomerisierungsveroii © 5a ©, Aue a glass tube were prepared _a each with a few drops of $ 56 d-4-carea sample containing filled and were then sealed ten capsules. Five ciieser capsules were in a temperature controlled bath of 220 ° C and the other five immersed in a 200 ° C bath. The vials were removed from the baths, cooled, opened and theirs at time intervals

- 41 -

209824/0998

U-

Contents gasohromatography examined. The analyzes resulted in a steady increase in d-4-carene, the formation of d-trans-Isoliiiionett in the appropriate amount and none remarkable change in the concentration of d-3-carene,

70 com of the above-described substance enriched with d ** 4 "cooking" was heated for four hours in a Druok bottle immersed in an oil bath at 220 ° C. After cooling, the infrared monitoring of a sample did not reveal any remaining d-4- * carene, but essentially A mixture of d-trana isolimones and d ~ 3 ~ carene, Dae isomerate was fractionated in a 1/2 ^w ac 24 ^w #> solid column at AtmosphBrendruok, a concentrate of d ~ trans «isolimons being obtained. The best fraction was obtained nooh a little d-3-carene, but shows an optical rotation of + 140 ° in a 10 cm neat tube. Fractionation of the isolinion / d-3-carene-6a iso in a more effective column makes the d-trans -Isolimons completely separated from this, as described in example k «

7 5/10 ecm of impure d-trans-isolimones from the distillation with the 1/2 "column were slowly going into a slurry of 1 g of aluminum chloride in 20 oom toluene at 10 to 12 ° C brought in. It was stirred for 30 minutes, after which the catalyst was washed out with dilute hydrochloric acid. That Toluene was driven off by heating under low vacuum. A hard terpene resin was obtained which was brittle and easily disintegrated when refrigerated.

Example 10

An active catalyst was produced by stirring 1 g of sodium metal in 26 g of ^ -methylnaphthalene at 183 »*» 205 ° C. for 2.25 hours. It irarde a thick black suspension of a solid in a black liquid obtained "To this was added 25 cc of pure d-3-carene added Naoh an introduction period of 0.5 hours at 110 to 140 ° C was reacted for eight hours at 150 ° C. After washing out the catalyst, the gas chromatographic analysis of the product (based on ^ -methylnaphthalene-free basis) showed 1.06% 2-carene, 44.1 % d-4-carene, 5 ^, 1 $ d-3-carene and 0.75 % of higher-boiling substances, which are composed of m- and p-cymene and d-2,4 (8) -p-menthadiene.

After increasing the heating temperature to 170 to 180 ° C the response time was shortened, but also increased Amount of higher boiling substances. With a / S-methylnaphthalene / sodium system it is possible to distill the isomerized Carengemisoh out of the reaction mass and add early cooking to the catalyst.

Example 11

Duroh dispersing 0.975 g hair-grown potassium in 20 com refluxing o-xylene with the aid of a high-performance mechanical stirrer became an active catalyst manufactured. When the potassium was well dispersed,

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209824/0993

the mixture was cooled to 90 ° C. and 15 μm of a 15th solution of n ~ butyllithium in hexane was added. This mixture was held at 110-125 ° C for 19 hours. After removal of the catalyst, gas chromatographic analysis of the product showed 42.6 % d ~ 4 ~ carene _t 52.4% d-5-carene and 4.3% higher-boiling by-products (on a solvent-free basis) «

Example 12

An active catalyst was produced by stirring 0.575 8 frlßiAgesohnem sodium with 16 ecm | ^ -picoline for 50 minutes at 143 ° C with a yard power converter. 13.6 g of pure C1-3-carene were added to this mixture, and the whole was stirred S2 hours at 23.1 & is 1% 3 "After removal of the catalyst and d ©© ¹ Fikoilas the product was examined gaschromatographigeh _β wherein 0 _p 8 io 2-carene, 39.9 fo d-4-carene, 56.7% d ~ 3 cooking and 2.6 <fo higher boiling substances resulted,

Example 13

By stirring 0.694 g of lithium metal at 50 ecm Ethylenediamine in a 500 ccm flask under a nitrogen atmosphere an active catalyst was produced at 110 to 116 ° C. It developed a blue tint that became paler with increasing conversion of lithium. As the blue color had disappeared, the mixture became further

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209824/0998

heated for two hours at 100 to Il6 ° C and stirred.

The reaction flask was then immersed in a constant temperature bath of 86 ° C ± 0.5 ° C, and the solution of Lithium in ethylenediamine was added to 158 com d-3-carene. The mixture was stirred and heated under a nitrogen atmosphere for a further two hours, after which the mixture was cooled and dried over water was left standing. The gas chromatographic examination a sample showed that the method had established a Carene balance. It was determined, that it is possible to equilibrate two further portions of 158 g of d-3-carene with the same catalyst, each of these passes decreasing the catalyst activity.

Example 15a

An active catalyst was prepared on foigetule Heise with 3 '3.8 g A1 »Q * (Harehaw alumina Al OIOEP) 100/300 mesh was obtained by heating in a stainless steel tube at 500 ° C and at 3 to 5 torr for 20 hours getjrceiämQ'üo tJÖSasOBSö öieaea * Since trarde tiüreh the pipe

sloweaor g) ti © föoto £ gatr <Mi headed, "- ^: '

The fired alumina was cooled and provided under nitrogen in a eisi © with a stirrer 100 oom flask over ^r _ g 3.J.55 Mairiummetall contained. Bas mixture

was then heated to 150 ° C and to disperse the

209824 / 099Ö

Sodium stirred on the clay for two hours. The resulting black catalyst contained 8 $ sodium, 7 9/10 g of this catalyst (cooled, under nitrogen) was slurried with hexane and transferred to a 100 eom flask equipped with a stirrer, which contained 40 oea d-5-carene Mixture was stirred and heated from tree temperature to 90 ° C. The gaaohromatographic analysis showed that after 48 minutes a carene balance weight had been set,

Example 14

200 com toluene were introduced into a distillation vessel of a 1 "π 4β"? * Fraction column filled with interlocking packings. Of this, 50 com were distilled off to ensure dryness, after which 6 g of freshly dissolved sodium and 3 com o-sulphate oil were added to the vessel. This mixture was refluxed overnight to form an active catalyst. Then 250 cc »d-3-carene (95 % » unit, free of 4->carene> were slowly added through the column, maintaining at reflux in order to prevent the entry of tuft xu . The toluene was then distilled off and the distillation of fermentation started at a low overflow ratio to allow isomerization and rectification Infrared test of the contents of the still, that it consisted mainly of m- and p-Gymol,

«46-

209024/0901

Example 15

A 1 / s teaspoon of an aqueous slurry of a low activity Raney Niokel catalyst was placed in the bottle of a Parr Sohaker. Swirling isopropanol a total of three times, allowing to settle, and decanting removed the water from the nickel. As much isopropanol as possible was poured off, after which 198 g of teohnisoh pure d-3-carene (purity 90 to 95 %, free of 4 cooks) were poured into the bottle. The hydrogenation took place under an initial hydrogen pressure of 50 psig and room temperature. the reaction proceeded slowly and was naoh about three days interrupted · During this time were about 75 i · absorbed the theoretical for the saturation of a double bond amount of hydrogen. During the hydrogenation, four samples were taken and examined by infrared spectrometry. These samples showed that the concentration of d-4-carene increased to a maximum and then with continued hydrogenation of d-3-carene and. d-4-Caren au Caran decreased again. ;

This partially hydrogenated Gemisoh that; essentially Caran, d-3-carene and d-4-carene contained, was in a Distillation plant with a 1 «xa & 8" packed column filled with interlocking Flini bodies and at a return flow ratio of 30ϊΐ and 25 Torr fractionated. The column was for such a sharp separation between these constituents boiling close together not sufficient, but the fractions were not continued.

209824/0998

gradual distillation successively with caran, 4-carene and 3-carene enriched as by infrared examination of the parliamentary groups has been established "

Example 16

In the bottle of a Parr Sohüttlers were I98 g technically pure d-3-carene (90 to 95 #) "that, as determined by infrared examination _p contained no 4-carene, and h g of a 5 follow Pd-carbon catalyst introduced . The device (including the storage container) was filled with hydrogen to a pressure of 5 p, sig » _4, after which the Sohüttler was allowed to run for two hours. The contents of the flash were then examined by infrared analysis; the pressure had dropped to 0 psig during this time. Negligibly small amounts of d-4 cooking were detected. " Until the device was again filled to a pressure of 5 p ₀ 8 _{0 ieg e} with T3 gas, and left to lam for a further two hours. After this, a robe indicated that a small amount of d-4-carene had been formed The pressure was then increased to 50% and the hydrogenation continued for 24 hours a Heislampe heated for another 24 hours. There were about 20 $ mBlar than the theoretical amount of hydrogen to a double bond absorbs infrared _p and the last curve seen was Garan and the presence of non-Caran Bandenj the sohlieBlich as su! jl ^

associated with heptane. The formation of this Substance made from carene requires two moles of hydrogen, from which the theoretical amount to be absorbed is greater Amount of hydrogen explained.

Example 17

A technically pure, 95 # d-3-carene (free of 4-carene) was placed in a Parr autoclave equipped with a stirrer. In these, based on the Oaren, 1 or 2% (as indicated below) copper chromite catalyst entered. As also stated below, the prevailing Pressures of 100 p.s.i.g. and 500 p.s.i.g. All runs were carried out at 165 ° C. The samples were filtered off from the catalyst and infrared spectrometry and examined by gas chromatography «The following results were obtained:

Run # Catalyst Pressure Time GC Analysis (psig)

1 1,500 10 h 21.3% d-4-carene

66.3 # d-3-carene

22,100 13h 29.6 # d-4-carene

54,> # d-3-carene

3 2 100 13 h 32.2f. d-4-carene

49.2 % d-3-carene

Runs 1 and 2 were made using 400 g d-3-carene and Durohlauf 3 carried out using vim 1200 g. The very slight drop in hydrogen pressure indicated by the manometer indicated that a

BADORfGJNAL ~ ^V) "

209824/0998

161852t

minor hydrogenation equilibrium the Carene accompanied »The gas chromatographic analysis showed that the Nioht-Garene almost completely ahead of the Carene eluted. It was believed to be saturated Hydrocarbons were, but were not identified.

After removal of the catalyst to convert the d-4 ** carene into d-trans isolimines, the substance from run 3 was treated in an autoclave at 220 ° C. for four hours. It was found and a change in the 3-Caren ~ Göhaltes, Fractionation of thermally boh ^ ndölton product in a chamber filled with interlocking Püllkörpern l ^w χ "10" - column then gave d ^ trans Isolimonen, ehr the "or less contaminated by hydrogenation was wonaoh d-3-carene followed which was suitable for re-use. Although this method, a d-trans-Isoliiaonen produces lower t purity than the isomerization with a basic catalyst plus heat treatment, at least interfere with the impurities, the saturated hydrocarbons are, in general not the further treatment stages of the thus obtained d-trans isolimony "

Example 18

In a 500 ocm flask equipped with a stirrer were 110 g of dry dimethyl sulfoxide and 9 g of potassium tert-butoxide brought in. This Gemisoh was made with 25 ecm

209824/0998

d-trans isolinrons displaced by 25 C. The temperature rose rapidly to 34 ° C and then slowly fell, so that it was 15 minutes after the addition of the d-trans isolimony to 32 ° C had sunk. This mixture was after this time as well as 1 hour, two hours and three hours after the addition a sample of the d-trans isolimony was taken. After this The first two samples were analyzed by gas chromatography and all four samples by infrared spectrometry. The gas-chromatographic analyzes of the first two Samples were as follows:

Component no.

Sample after 15 min.

Sample after 1 hour %

identity

1 2.1 2.1 Not identified 2 7.1 12.7 ^ -Terpines 3 0.1 0.3 Not identified 4th 2.0 3.8 Not identified 5 8.8 8.2 3,8-p-menthadiene 6th - 2.2 Not identified 7th 7a, 5 69.2 d-2,4 (8) -p-menthadieη 8th 0.3 0.4 Not identified 9 0.4 0.3 Not identified 10 0.7 0.7 Not identified 11 0.2 0.2 Not identified

The last two samples showed an increasing increase in «(-terpinene and a decrease in d-2, A (8) -p-menthadiene, each the more the balance leaned toward the side of p-menthadiene.

- 51 209824 / 099S

The same experiment was repeated at 65 ° C., and after A sample was taken after one hour. The infrared spectrogram showed that the equilibrium of the p-menthadiene mixture had completely stopped.

Example 19

10 g of sodium metal and 100 g of toluene were placed in a 500 cm flask equipped with a stirrer. The mixture was heated to reflux with stirring, after which a mixture of 43 gd ~ trans ~ isolimone hydrochloride was poured through a dropping funnel. (8-chloro-2-menthene), which was prepared by adding 1 mole of HCl to 1 mole of d-trans isolimones, and 25 g of tert-butymnol were introduced. This addition was extended over a period of 30 minutes. The mixture became quite thick after five minutes, so that another 100 com of toluene had to be added through the reflux condenser. Stirring under reflux was continued for 5 1/2 hours, wonacfyaas refluxing mixture was treated cautiously dropwise with water to destroy the residual sodium i and decompose the alkoxide. After the washing, most of the toluene was distilled off with a column and the crude product was examined by infrared spectrometry and gas chromatography. Gas chromatographic analysis (on a toluene-free basis) showed 86 fo d-trans-2-menthene, which was supplemented by mixed menthadienes, which resulted from the HCl removal of the d-trans-isolimone hydrochloride by a base «since these impurities boil higher as d-trans-

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2-rMenthen, they can easily be made by fractional distillation be removed,

Example 20

In one equipped with a nitrogen inlet and a stirrer 500 oem flasks were 68 g of d-trans isolimones and Introduced 50 g of triisobutyl aluminum. The mixture was heated to 120 ° C, after which a dropping funnel a sufficient amount of heptane was introduced so that the

"Gemiso was gently refluxed at 120 ° C.

Heating and stirring continued overnight. The gaseous isobutylene (28 g) evolved during this time was caught in a cooling lock. After cooling to room temperature, excess liquid was carefully added dropwise Water was added, the temperature being increased through a cooling bath for most of this addition held less than 50 ° G. At the end of this addition, however, the temperature was allowed to rise to 70 ° C. Of the

| l water addition was terminated when no further exothermic Reaction was observed * During the addition of water, 6 g of isobutane were collected in the cooling sole from the decomposition of excess isobutylaluminum introduced caused by the water). The infrared examination the heptane solution gave d-trans-2-menthene, no residual d-trans isolimones, no other menthenes, so that it can be seen that no isomerization of the ring double bond had taken place.

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Example 21

In a vessel equipped with a stirrer 5OG ocm flask 80 g of pyridine was heated under reflux for * Then slowly 43 g of d-trans ^ laolimonen-hydroohlorid (8-chloro-2-menthene) _f were prepared by addition of Ϊ mol BOl to 1 mole d-trans isolimotia, slowly introduced "The stirring at reflux was continued for four hours, with samples being taken after one, two and four hours." hydroohiQridfi with dilute hydrochloric acid showed the Infrarotuntersuohung of the samples, that the product consisted primarily of d-2 _t% (8) -p-menthadiene and a small amount zurüokgebildetem d-trens-laolimonen * amounted the optical rotation in a "10 em-tube +7? ° »The reaction was already complete after the first hour *

A similar treatment using ethanol isoher KOH solution, made up of 200 g of methanol and 20 g KOH platelets, also resulted in d-2,4 (8) -D- »menthadiene as main pj? oduct, because of the low reflux temperature (67 ° C) were nearing completion of the reaction two hours required. The presence of very faint methoxyl bands in the infrared spectrum indicated that the ether formation was a minor side reaction »

Ex iel 22

Example 13a repeats, with the exception that instead of sodium, potassium is used to prepare the catalyst

209824 / 099Ö " ⁵ ^" *

was used, The results were gotiaiiso satisfactory *

By the process according to doi * invention, d-3-carene can be rearranged into d-4-carene in good yield. Although the description and examples are directed primarily to the use of d-3-carene, 1-3-carene can be rearranged to 1-4-carene with equal success by the process of the invention. Can likewise mixtures * '■ 1-4 Caren be rearranged of d- and 1-3 Caren in Gemisohe of d- and.

The ones used to rearrange 3-carene into 4-carene Hydrogenation catalysts are precious metals like platinum and Palladium, base metals such as nickel and cobalt, and metal oxides like copper ohromite. This rearrangement is caused by the presence of hydrogen with an above atmospheric ' druok lying Druok completes * The pressure under which the hydrogen is introduced fluctuates primarily Line depending on the catalyst used. It will be easy for those skilled in the art to understand the teachings and working examples of the present invention for the rearrangement of 3-carene into 4-carene in good

! prey to choose suitable hydrogen pressure.

At the moment the area of application of 4-carene is only small. It is used as a solvent for paints and as a cleaning agent

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medium used for paint brushes «According to the invention, however, 4-carene is preferably used for the production of isolimones. The d-4-carene obtained by isomerization of d-3-carene is converted into d-trans isolimones by heating at an elevated temperature for a sufficient time. It is advantageous to use relatively high temperatures for this conversion, which means that a minimum of time is required for the conversion of d-4-carene to d-trans-isolimouene. In addition to the above-mentioned time-temperature relationships, two minutes at 280 ° C, about 30 seconds at 300 ° C, about 0.7 seconds at 350 ° C, about 0.016 seconds at 400 ° C and about 450 ° are required for complete conversion C takes about 0.0004 seconds.

The d-trans isolimones obtained according to the invention can are polymerized to hard solid polymers or resins, which are used as components of adhesives, protective

Overlays and the like find application. ^

The preferred field of application of d-trans isolimones is used in the production of 1-menthol, for this purpose the d-trans isolimones, as explained above, initially either in d-trans-2-menthene or in d-2, A (8) -p-menthadiene converted. Both compounds can be converted to 1-menthol by methods already known will,

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It can be seen from the description and the examples that d-3-carene isomerizes to d-4-carene in good yield by bringing d-3-carene together with relatively strongly basic mixtures. This catalyst system consists of a basic mixture, the basicity of which leads to the formation of carbanions of the d-3-carene when brought together with this is sufficient. When using d-3-carene as a starting material, the isomerization is preferably at temperatures between about 23 ° C (room temperature) and 180 ° C are carried out. It \ n.rd not all of the d-3-carene rearranged in d-4-carene, but there is an equilibrium between d-3-carene and d-4-carene, in which d-3-carene dominates, one. The reaction can be interrupted at any desired time after the formation of d-4-carene has started. A reaction mixture of d-3-carene and d-4-carene in a ratio of 80:20 is economically justifiable. Usually it is appropriate to carry out the reaction until no more significant amounts of d-4-carene are formed, i.e. until the equilibrium between d-3-carene and d-4-carene has been established. The reaction is usually carried out in such a way that Until the ratio of d-3-carene to d-4-carene in the mixture is about 60:40 to 57:43.

As explained above, d-3-carene is rearranged in good yield with a catalyst system in d-4-carene which from a basic Alfealimetallgemiscli with a basicity

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exists, which is sufficient for the formation of carbanions of d-3-carene when brought into contact with it »

Base mixtures which can be used according to the invention are those which have previously been composed of an alkali metal and organic compounds which are capable of forming organometallic compounds with the alkali metal. These include monocyanic aromatic hydrocarbons such as toluene and xylene and polycyclic ^ aromatic hydrocarbons such as naphthalene, methylnaphthalene, anthracene, Fluorene, phenanthrene and tetralin are monocyclic aromatic hydrocarbon is used, it is appropriate to initiate the formation of the alkali metal - derivatives of the monocyclic aromatic hydrocarbon to add an accelerator such as o-chlorotoluene. As explained above, heterocyclic compounds can also be used. The heterocyclic compounds usually contain a ring with one nitrogen atom and at least four, but not more than five carbon atoms, The aforementioned accelerators such as o-chlorotoluene can be used with an alkali metal such as sodium and an organic compound can be used, but they can also be used to catalyze the isomerization reaction can be used with alkali metal alone. Just like o-chlorotoluene, other halogenated aromatic compounds can also be used Compounds used, such as o-bromotoluene, ■ o-chloroethylbenzene and o-bromoethylbenzene, alkali metal alkyls

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such as amyl sodium., amyllithium and butyllithium are suitable can also be used as base mixtures for the catalyst. These catalysts x ^ ground in an inert medium rfie Cyelohezian, Heptane, hexane, nonane and the like are used.

The following additional example serves to further Illustration of the invention.

Example 23

20 ecm of pure d-3-carene were added to a mixture of 8.5 ecm 0.8 N-amyl sodium in heptane and 20 ecm n-nonane. It was hei 52 minutes 100 ° C reacted "The analysis of the reaction mass showed (aui" solvent-free basis) 0.82 # d-2-carene, 43.7 ° / o d-4-carene and 55.5 ^c fo d- 3-carene,

Claims;

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Claims (1)

Patent claims t 1 «Process for the isomerization of d-3-caron into d-4-carene, that are thermally converted into d-trans isolimones cann, thereby gelcennzelehnet that d-3-carene with a Katalyc + or ^ rtem is brought together, which consists of a The group selected is (l) an alkali metal base mixture with a basicity necessary for the formation of carhan ions of d-3-carene after bringing it into contact with this is sufficient, or (s) a catalyst system consisting of a hydrogenation catalyst and hydrogen consists, wherein the hydrogenation catalyst is a noble metal, noble metal or metals; id. Process according to Claim 1, characterized in that the catalyst system is one of the following: a) a previously formed basic mixture of alkali metal and a polycyclic aromatic hydrocarbon, BAD ORiGINAL 209824/0998 TELEPHONE: 0184057 b) a previously formed basic mixture of an alkali metal imind a halogenated aromatic hydrocarbon, c) a previously formed basic mixture of an alkali metal .und a heterocyclic compound with a Ring made of one nitrogen atom and at least four and at most five carbon atoms, d) a previously formed basic mixture of a jilkali metal derivative an alcohol and a dipolar aprotic solvent, e) a previously formed basic mixture of an alkali metal and an amine, f) a basic mixture of alkali metal applied to alumina, g) a previously formed base raw mixture of an alkali metal derivative a non-aromatic hydrocarbon, h) a previously formed basic mixture of an alkali metal and a monocyclic aromatic carbonate material , i) a noble metal hydrogenation catalyst and hydrogen, j) a base metal hydrogenation catalyst and hydrogen and ■; c) a ketalloid hydrogenation catalyst and hydrogen. 3. The method according to claim 1 or 2, characterized in that the reaction with the catalyst at atmospheric pressure up to 500 p.s.i.ß. and at a temperature of 23 to 180 ° C pressure-cooled. , earth. BATH 209824/0998 4, method according to one of claims 1 to 3 _? characterized in that the reaction is carried out in the presence of "palladium, nickel, or copper chromite and hydrogen» 5 · method naoli one of claims 1 to 4, characterized characterized that the formed d - ^ - carene for a Conversion into d- »trans-isolimones on sufficient time a temperature of at least 180 ° C is heated, % _A method according to claim 5, characterized in that the d-trans isolimone is further converted into d ~ trans-2-menthene or d ~ 2,4 (8) -p-menthadiene. 7 * Method according to claim 51 characterized} that the d-trans-Isoliraanen selectively to d-trans ~ 2-Meiithen is hydrogenated, 8. The method according to claim 5 _}, characterized in that the d ~ trans isolimones for conversion to d-2,4 (8) -p-mentha ~ dien is brought together with a strong base. Ra - 19 827 209824/0888