DE2228333B2 - Process for the preparation of optionally substituted 2-butyn-4ols - Google Patents

Description

R ¹ O = CR ²

(Π)

R ¹

CH ₁ -C = CCR ³ OH

(I)

in which R ¹ and R ^{2 represent} hydrogen, a saturated or unsaturated, branched or unbranched aliphatic hydrocarbon radical with 1 to 20, preferably 2 to 13 carbon atoms, a cycloaliphatic hydrocarbon radical with 5 or 6 carbon atoms in the ring or a phenyl radical, or R »and R? together mean an alkylene radical having 4 to 6 carbon atoms, can be prepared in a very advantageous manner if an aldehyde or a ketone of the formula II

in which R ¹ and R ^{2 represent} hydrogen, a saturated or unsaturated, branched or unbranched aliphatic hydrocarbon radical with 1 to 20 carbon atoms, a cycloaliphatic hydrocarbon radical with 5 or 6 carbon atoms in the ring or a phenyl radical, or R ¹ and R ² together denote an alkylene radical having 4 to 6 carbon atoms, characterized in that an aldehyde or a ketone of the formula II

in which R ¹ and R ^{2 have} the meaning given above, in the presence of an alkali hydroxide, alkali alcoholate, alkali amide or metallic lithium as the alkaline condensation agent in a virtually water-immiscible solvent with a dielectric constant of less than 10 at temperatures of 0 to 50 ^° C reacts with all or a gas mixture containing all.

2. The method according to claim 1, characterized in that you practically not with water miscible solvents small amounts of mono- or polyhydric alcohols with 1 to 5 carbon atoms clogs.

The production of 2-butyn-4-ols by reacting aldehydes and ketones with propyne in the presence of alkaline condensing agents is known.

It is also known from German Offenlegungsschrift 55 843 that Propyne and Allen are thereby can mutually convert that the propyne and allene-containing gas with a catalyst solution in Brings contact, which consists of a dipolar aprolic solvent with a dielectric constant above IO and a hydroxide or alkoxide one Alkali metals with an atomic number higher than 10 consists.

It has been found that 2-butyn-4-ols of the formula I.

R ¹ O = CR ²

in which R ¹ and R ^{2 have} the meaning given above, in the presence of an alkali hydroxide, alkali alcoholate, alkali amide or metallic lithium as the alkaline condensation agent in a water-immiscible solvent with a dielectric constant of less than 10 at temperatures from 0 to 50 ⁰ C reacts with all or a gas mixture containing all

It was surprising that Allen was among those named Reaction conditions can be converted to 2-butyne-4-oils, since it is known on the one hand that for the mutual conversion of propyne and allene according to the German Offenlegungsschrift 19 55 843 the presence of very specific aprotic solvents is required and since, on the other hand, it is stated in German Offenlegungsschrift 16 68 399 that All even when treated with a dispersion of sodium or lithium containing sodium behaves relatively inert, while propyne is converted into the corresponding propynyl alkali metal compound. Furthermore, it is stated in the last-mentioned laid-open specification that pure metallic lithium is among the Reaction conditions even with propyne did not react

For the conversion to 2-butyn-4-ols can be pure All to be used. However, this is used with particular advantage in the case of the thermal Splitting of saturated hydrocarbons, a mixture of allene and propyne, which only occurs through very expensive distillation processes would have to be separated into allene and propyne. An extensive cleaning of the Allen-propene mixture is not necessary, since such gas mixtures according to the invention also have no disadvantages can be used which contain other hydrocarbons, olefins or diolefins in addition to allene and propyne.

Compounds of the formula II are used as aldehydes or ketones

R ¹ O = CR ²

in which R ¹ and R ² respectively represent hydrogen, a saturated or unsaturated, branched or

ν, unbranched aliphatic hydrocarbon radical with 1 to 20 carbon atoms, a cycloaliphatic hydrocarbon radical with 5 or 6 carbon atoms in the ring or a phenyl radical, or R ¹ and R ² together represent an alkylene radical with 4 to 6 carbon atoms, in

M) consideration. Of particular interest are aldehydes or ketones in which R ^{1 represents} hydrogen or a saturated hydrocarbon radical having 1 to 4 carbon atoms and R ^{2 has} the meaning given above for R ¹ and R ^2. Examples include: acetaldehyde,

h'i propionaldehyde, isobutyraldehyde, citronellal, acetone, Methyl ethyl ketone, methyl isobutyl ketone, 2-methylhepten-1-one-6,2-methylhepten-2-one-6, geranylacetone or Hexahydrofarnesylacetone.

AJ's basic condensing agents are in particular the hydroxides, alcoholates and amides of sodium and potassium into consideration, metallic lithium can also be used be used. The process according to the invention can be very particularly advantageously with sodium or Potassium alcoholates of primary or secondary Carry out alcohols with 4 to 8 carbon atoms, since these alcoholates are particularly economical from aqueous Alkali solutions can be obtained by azeotropic distillation with the only limited water-soluble alcohols can. The alkaline condensing agents are generally used in amounts of about 0.2 to 1.5 mol, preferably 0.3 to 1.0 mol per mole of aldehyde or Ketone used If potassium-containing condensation agents and tetrahydrofuran are used as solvents, even the use of catalytic ones is sufficient Amounts, i.e. amounts of about 0.2 to 0.5 mol Condensing agent per mole of aldehyde or ketone.

As a practically immiscible solvent with a dielectric constant of less than 10 come aliphatic or aromatic hydrocarbons, such as toluene, xylene, dialkyl ethers, such as diethyl ether, cyclic ethers such as tetrahydrofuran, hexamethylene oxide and dioxane and the acetals lower aliphatic aldehydes, such as the diacetals of formaldehyde or acetaldehyde with aliphatic Alcohols having 1 to 4 carbon atoms can also be used. Mixtures of the solvents mentioned can also be used. In particular, as a solvent called: Tetrahydrofuran and cyclic ethers of the tetrahydrofuran type and formaldehyde dibutyl acetal, Formaldehyde diisobutylacetai, acetaldehyde diethylacetal Acetaldehyde dibutyl acetal, acetaldehyde diist-vutyl acetal, Dioxane. The organic solvents are generally used in amounts of about 3 to 15, preferably 5 to 10 parts by volume per part by volume of aldehyde or ketone.

The organic solvents must not contain any free hydroxyl groups or amino groups, because this reduces the effectiveness of the basic condensation agent.

On the other hand, when using extremely difficult to dissolve or difficult to suspend condensing agents - such as the alkali hydroxides - of Advantage of adding small amounts of a compound containing hydroxyl groups as a solubilizer to the reaction mixture. Come as a solubilizer Particularly mono- or polyhydric alcohols with 1 to 5 carbon atoms such as methanol, ethanol, isobutanol, ethylene glycol or glycerol are suitable. The solubilizers are generally used in amounts of 0.5 to 5 parts by volume per 100 parts by volume of the solvent.

For performing the method a suspension of the alkaline condensing agent in the selected solvent or solvent mixture with all or the Allen-containing gas mixture is first saturated in general, and then at temperatures from 0 to 50 ° C, preferably 10 to 30 ⁰ C ₁ the aldehyde or ketone slowly entered with further passage of the gas or gas mixture. The exhaust gases leaving the reaction mixture are collected and, if necessary, fed back into the process.

When the aldehyde or ketone has been introduced, water is added to the reaction mixture and the phases that form are separated from one another. The organic phase is neutralized and then distilled. Any inorganic or organic acids that do not chemically change the reaction product are used for neutralization. For example, called sejen; Formic acid, acetic acid, adipic acid and sulfuric acid. During the distillation of this organic phase, the amounts of unreacted allene or gas containing gases still dissolved in the solvent are recovered.
From the aqueous alkaline phase can through

ι ο Reacting with primary or secondary alcohols with 4 to 8 carbon atoms and subsequent azeotropic distillation, the alkali metal alcoholates of these only limited water-soluble alcohols which can be used as alkaline condensation agents are obtained.

is The reaction of the aldehyde or ketone with all or the all-containing gas mixture can also be carried out under increased pressure. These Working method is advantageous if the solvent pure a low solubility for all or all containing gas mixture has such. B. with xylene or toluene. In most cases, however, there is a Working under increased pressure is not necessary.

With the help of the process according to the invention, it is possible to use the butynols of the formula I in a simple and

2) economical way from the as a by-product in the

Manufacture of all or all of butadiene

containing gas mixture and carboxyl compounds to manufacture.

The conversion of all to propyne and the

jo reaction of propyne with the carbonyl compound takes place in the same reaction medium. The work-up of the reaction mixture after the reaction is complete extremely simple, since the solvents used with the one added to the reaction mixture

r, water are not miscible. Through this simple Wastewater and thus environmental protection problems are avoided. Continue to let the solvents used according to the invention are easily and completely removed from the acetylene alcohols formed separate, whereby very pure acetylene alcohols are obtained, which is not the case with solvents such as dimethyl sulfoxide and N-methylpyrrolidone, for example Case is The butynols of formula 1 produced have as

• n intermediates for organic syntheses, as sleeping and sedatives as well as fragrances of interest. In particular that from 2-methylhepten-2-one-6 or 2-methylhepten-l-one-6 with all or all-containing gases produced 2,6-dimethyl-2-nonene 7-yn-6-ol and 2,6-dimethyl-1-nonene-7-yn-6-ol show good fragrance properties.

The parts mentioned in the following examples are parts by weight.

^y ' B e i s ρ i e I 1

The suspension of 112 parts of potassium isobutylate in 67 Parts of xylene are distributed in 1600 parts of tetrahydrofuran with stirring, and the suspension obtained

bo for one hour at temperatures of about 25 ° C saturated with pure all. About 150 parts of all are solved in the process.

In the course of 4 hours with further passage of all at temperatures from 25 to

hi 3O ⁰ C 252 parts of 2-methyl -! - hepten-6-one entered. 24 parts of exhaust gas are collected in a freezer. The exhaust gas has the following composition: 84% Pronin and 16% Allen.

After the ketone has been introduced, 100 parts of water are added to the reaction mixture. Make it up 120 parts of an aqueous 43% strength potassium hydroxide solution, which is used again for the production of potassium isobutylate can be.

The organic phase formed is neutralized by adding 2 parts of formic acid and then distilled. During this distillation, the unreacted allene-propyne mixture dissolved in the solvent is collected. 276 parts of 2,6-dimethyl-l-nonen-7-yn-6-ol with a boiling point bp _s = 99 ° C. and 31 parts of unreacted 2-methyl-lhepten-6-one are obtained. The yield is 94.5% of theory, based on converted 2-methyl-1-hepten-6-cn.

Example 2

In the suspension of 112 parts of potassium isobutylate in 67 parts of xylene and 1600 parts of tetrahydrofuran is introduced at 20 ° C, a gas mixture, which except other hydrocarbons, olefins and butadiene contains 44% allene and 22% propyne after 1 hour Saturation of the suspension with the gas mixture is started with further introduction of the gas mixture 252 Parts of 2-methyl-2-hepten-6-one to enter. The entry is ended in 3 hours. The reaction temperature is kept at 20 ° C during the introduction.

The reaction mixture is then mixed with 100 parts of water, the aqueous potassium hydroxide solution formed separated, the organic phase neutralized by Zugsbe of 1 part sulfuric acid and then distilled 268 parts of 2,6-dimethyl-2-nonen-7-η-6-ol are obtained with a boiling point Κρ <«= 65 to 66 ° C and 22 s parts unreacted 2-methyl-2-hepten-6-one. The yield is 88.5% of theory, based on 2-methyl-2-hepten-6-one.

Example 3

ίο Pure allene is introduced into the mixture of 7 parts of lithium chips and 500 parts of tetrahydrofuran with stirring. The temperature of the mixture initially rises to about 45 ° C., but then falls again. With simultaneous introduction of further Allen 126 parts of 2-methyl-2-heptcn-6-one are introduced into the mixture at 20 to 30 ⁰ C in the course of 4-8 hours. A total of 120 parts of allene are passed in. The reaction mixture is mixed with 20 parts of water. The separated organic phase is neutralized and distilled. The distillation gives 138 parts of 2,6-dimethyl-2-nonen-7-yn-6-ol with a boiling point of bp8 = 97 ° C and a refractive index π = 1.4685 and practically no unreacted 2-methyl-2-hepten-6-one. The yield of 2,6-dimethyl-2-nonen-7-yn-6-ol is 83% of theory.

The 80 parts of the gas mixture recovered in the distillation in a deep-freeze receiver exist 60% from all, 7% from propyne and 33% from propylene.

Claims (1)

Claims; 1, Process for the preparation of optionally substituted 2-butyn-4-ols of the formula I. R ¹ CH ₃ -C = CCR ² OH U)