EP0929505A1

EP0929505A1 - Process for preparing alkyne diols or mixtures of alkyne diols with alkyne monools

Info

Publication number: EP0929505A1
Application number: EP97944774A
Authority: EP
Inventors: Thomas RÜHL; Jochem Henkelmann; Achim Stammer; Susanne Stutz
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 1996-09-03
Filing date: 1997-08-21
Publication date: 1999-07-21
Also published as: CA2260814A1; KR20000068405A; JP2000517326A; WO1998009932A1; DE19635703A1

Abstract

The invention concerns a process for preparing alkyne diols or mixtures of alkyne diols with alkyne monools by reacting acetylene with more than equimolar amounts of ketones and/or aldehydes in the presence of an alkaline compound, the alkaline compound being used in a molar amount which is less than half the molar amount of the ketone and/or aldehyde to be reacted, in the presence of ammonia and/or at least one reactive primary amine.

Description

Process for the preparation of alkynediols or mixtures of Al - kindiols with alkyne monools

description

The present invention relates to a process for the preparation of alkynediols or mixtures of alkynediols with alkyne monools by reacting acetylene with more than equimolar amounts of ketones and / or aldehydes in the presence of an alkali compound.

Alkyne diols and mixtures of alkyne diols with alkyne monools are valuable intermediates for the production of e.g. low-foam surfactants, pyrethroids, electroplating aids or peroxides.

Processes for the preparation of alkynediols or alkyne monools have long been known. The preparation of alkynediols is generally considerably more complex than the preparation of the alkyne monools. For this, ketones or aldehydes are reacted with acetylene using a basic compound in a stoichiometric manner. A potassium alcoholate or potassium hydroxide is usually used as the basic compound. At least one mole of the potassium hydroxide or alcoholate is required to react 2 moles of ketone or aldehyde with one mole of acetylene. A solvent is usually used for this reaction. The prior art teaches various embodiments of these processes which differ in the solvent, in the sequence in which ketone or aldehyde, acetylene and the basic condensing agent are added, and in the type of basic condensing agent.

For example, DE-A-20 08 675 teaches the use of potassium alcoholates of primary or secondary alcohols in hydrocarbon solvents. DE-A-20 47 446 teaches the conversion of alkyne monools into alkyne diols by condensation of the monools with aldehydes or ketones. US-A-21 63 720 teaches the reaction of ketones with solid alkali metal hydroxides and the further treatment of the resulting mixture with acetylene at a temperature which avoids the base-induced condensation of ketones. The ketone can be present in excess and can be used as a solvent, but this excess can be replaced by another solvent such as ether. Based on the ketone to be reacted, an at least stoichiometric amount of alkali hydroxide is also used. In EP-A-285 755 the use of Al-alkyl is tert. -butyl ether taught as a solvent to reduce the often high viscosity of the known reaction mixtures. EP-A-285 755 points in column 1, lines 18-20 as well DE-A-20 47 446 in column 1, line 27 to column 2, line 4, in particular on the difficulty in the preparation of alkynediols, in particular the bis-tertiary alkynediols formed by the reaction of ketones with acetylene compared to the preparation of the alk n -Monoole hm.

US Pat. No. 3,082,260 teaches the preparation of alkyne monools by condensation of acetylene with ketones or aldehydes in liquid ammonia as solvent using about 5 to 25 mol% of alkali metal hydroxide, based on the ketone or aldehyde used, as a catalyst. In the subsequent distillation of the monools, a small residue is obtained which, in addition to products from side reactions, also contains the corresponding diol.

US-A 32 83 014 teaches the production of alkm monools while avoiding the formation of alkynediols by reacting ketones with acetylene and an aqueous solution of alkali metal hydroxide as a catalyst. The alkali hydroxide is used in an amount of 0.5 to 10 mol%, based on the ketone used. The solvent is ammonia.

The known processes for the production of alkynediols have the main disadvantage of the stochiometric use of alkali metal fertilizers. The preferred potassium alcoholates or potassium hydroxide are relatively expensive, must be used essentially free of water and are obtained in the form of a dilute aqueous solution of potassium hydroxide after the usual aqueous work-up of the reaction product. Working up the base by evaporating this solution, cleaning the residue and, if necessary, converting it into an alcoholate is technically possible, but comparatively cumbersome, lengthy and, above all, uneconomical due to the high energy expenditure when evaporating the water.

The invention had for its object to find a process for the preparation of alkynediols or mixtures of alkynediols with alkyne monools by reacting ketones and / or aldehydes with acetylene, which does not require the stoichiometric use of alkali metal hydroxide or alkali metal alcoholate.

Accordingly, a process for the preparation of alkynediols or mixtures of alkynediols with alkyne monools by reacting acetylene with more than equimolar amounts of ketones and / or aldehydes in the presence of an alkali compound was found, which is characterized in that the alkali compound in a smaller molar amount than half the molar amount of the setting ketones and / or aldehydes in the presence of ammonia and / or at least one reactive primary amine.

Compounds of sodium, potassium, rubidium and cesium, in particular those of sodium and potassium, are suitable as the catalyzing alkali compound. Alkali hydroxides and / or alkali alcoholates are preferably used. Examples of catalysts which can be used according to the invention alone or in a mixture are sodium hydroxide and potassium hydroxide, sodium methoxide, sodium ethanolate, sodium propanolate, sodium isopropanolate, sodium butanolate, sodium isobutanolate, sodium tert. -butanolate and sodium tert. -amylate, potassium methoxide, potassium ethanolate, potassium propoxide, potassium isopropoxide, potassium butoxide, potassium isobutanolate, potassium tert. -butanolate and potassium- tert. amylate. The potassium compounds are preferably used, and potassium hydroxide and potassium methoxide are particularly preferred.

The alkali compound can be used in solid form or as a solution or suspension in a solvent or suspending agent. As a rule, solutions or suspensions are easier to handle and easier to dose in precise quantities than solids, which is why the use of a solution or suspension of the alkali compound is generally preferred over the use of the alkali compound as a solid. The difference between solution and suspension is generally not sharply defined; depending on the solubility of the alkali compound in the chosen solvent, part of the alkali compound can be dissolved and the rest in suspension. The choice of this solvent or suspending agent is generally not critical and is only subject to the condition that it must be inert to the reactants. Mono-alcohols such as methanol, ethanol, n-propanol, iso-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol, tert. -Butanol or diols such as glycol, propylene glycol, alkyne monools, alkyne diols or mixtures of alkyne diols with alkyne monools such as the products of the process according to the invention are used. Water can also be used as solvent, the concentration of the alkali compound in the water preferably being chosen so that the amount Water, which is finally present in the actual reaction mixture, does not exceed 10% by weight, based on the reaction mixture. Ethers such as diethyl ether, dibutyl ether, tetra-hydrofuran, methyl tert. -butyl ether or ethyl tert. Butyl ethers can be used as well as hydrocarbons, for example pentane, hexane, heptane, cyclopentane or cyclohexane or mixtures thereof. Highly polar, aprotic solvents can also be used, examples of this class of substances are Dimethyl sulfoxide ("DMSO"), sulfolane and N-methylpyrrolidone. Liquid ammonia can also be used. Preferably, the product of the reaction as a solution or suspen sion medium ^¬ is used for the alkaline compound.

The molar amount of the alkali compound used in the reaction mixture is less than half the molar amount of the ketone and / or aldehyde to be reacted. In general, 0.1 to 5 mol of alkali compound, based on the ketone to be reacted and / or the aldehyde to be reacted, are added. Preferably, 0.2 to 1 mol% of alkali compound, based on the ketone to be reacted and / or the aldehyde to be reacted, is added. The use of larger amounts of alkali is technically possible, but because of the increasing use of alkali and / or the effort for its reprocessing, it is generally less and less advantageous economically with increasing amount of alkali. The use of smaller amounts of alkali is also technically possible, but is generally economically disadvantageous due to the long reaction times.

The reaction mixture contains ammonia and / or at least one reactive primary A in as the cocatalyst. The amount of cocatalyst is generally at least equimolar to the amount of the alkali compound or the alkali compounds used. Preferably at least twice that to the amount of the alkali compound used or the equimolar amount of ammonia or primary amine used in the alkali compounds and, in a particularly preferred manner, at least five times. For example, amino-substituted alkanes having 1 to 4 carbon atoms can be used as the primary amine.

Examples of primary amines which can be used according to the invention are low molecular weight alkylamines, for example alkylamines having one to four carbon atoms, such as methylamine, ethylamine, 1-propylamine, 2-propylamine, 1-butylamine, 2-butylamine, 2-methyl-1-propylamine and 1, 1-dimethylethylamine. Mixtures of at least two amines or mixtures of at least one amine with ammonia can also be used. Ammonia and / or methylamine are preferably used, very particularly preferably ammonia.

In principle, the process can be carried out without any further solvent. The process can likewise only be carried out in the presence of the solvent or the suspending agent of the solution or suspension of the alkali compound if the alkali compound is added in a solvent or suspending agent. However, the process can also be carried out in the presence of a solvent specifically used for the reaction whose selection is subject to the same condition as the choice of solvent or suspension medium of the alkali compound. All solvents which dissolve acetylene, such as N-methylpyrrolidone, dioxane, dimethyl sulfoxide ("DMSO"), sulfolane or THF, and ammonia or primary nurses are also suitable as solvents. The usable as solvent pri maren nurse can be selected on e as usable as cocatalyst Primae ^¬ ren. Ammonia is preferably used as the solvent.

In the context of the present invention, compounds of the general formula I are used as ketones or aldehydes:

0

(I)

R ^l R2

used. There is no restriction per se with regard to the choice of the residues, so that all inert organic residues, for example those with one to 50 carbon and / or heteroatoms, come into consideration. For example, R ¹ and R ² in this formula independently of one another denote alkyl, alkenyl, aryl, alkylaryl, aryl alkyl or arylalkenyl radicals which can be straight-chain or branched, open-chain or cyclic, substituted or unsubstituted. The term aryl stands for example for phenyl or naphthyl. Instead of aryl radicals, heteroaromatic groups such as heteroaromatic rings, which can contain one or more heteroatoms such as nitrogen, oxygen or sulfur, can also be present. In the same way, the radicals can also be aliphatic or cycloaliphatic, both saturated and olefinically unsaturated. These aliphatic or cycloaliphatic radicals can also contain one or more heteroatoms such as nitrogen, oxygen or sulfur. In addition, the radicals R ¹ and R ² can be linked to one another and, together with the carbonyl group, form a ring system which can also be olefinically unsaturated and can also contain heteroatoms such as nitrogen, oxygen or sulfur. All of the radicals mentioned can be inert substituents such as, for example, alkyl or alkoxy radicals

Wear halogen atoms such as fluorine, chlorine, bromine or iodine. In the case of aldehydes, R ^{2 is} hydrogen; in the special case of formaldehyde, both R ¹ and R ^{2 are} hydrogen. Examples include ketones such as acetone, methyl isobutyl ketone, methyl ethyl ketone, methyl heptanone, methyl heptenone, methyl norbornenyl ketone, trimethylcyclopentanone, acetophenone, benzophenone, methyl vinyl ketone and ionone.

Suitable aldehydes are, for example, formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, 2-ethylhexanal, benzaldehyde or substituted benzaldehydes such as 4-tert-butylbenzaldehyde.

In general, it is expedient to use only one ketone or one aldehyde, but in principle it is also possible to use mixtures of at least two ketones, mixtures of at least two aldehydes and also mixtures of at least one ketone with at least one aldehyde. In this case, mixtures of products are obtained which are then worked up together and used further as mixtures or which can be separated into individual components in the course of the work-up. It is also possible to separate the product mixture resulting from the reaction of acetylene with various ketones and / or aldehydes, for example by physical methods, for example by distillation, into cuts or fractions, ie not to obtain the individual compounds, but rather new mixtures of the Products whose composition differs from that of the original mixture and to continue using these cuts or fractions.

The concentrations of the reactants involved and the amount of solvent can be chosen relatively freely according to the requirements of the proper operation of the process (criteria can be, for example, the viscosity of the reaction mixture, the desired, economically optimal space-time yield, the selectivity or the amount of acetylene which can be handled safely ). The optimum amounts of ketone, aldehyde, acetylene and solvent for the products desired and the educts used in each case can vary. To achieve a satisfactory yield of alkynediols, however, it is necessary that the molar ratio of ketone and / or aldehyde to acetylene is higher than 1: 1. It is preferably at least 1.2: 1. If the production of pure alkynediols or a predominant proportion of alkynediols in a mixture with monools is desired, this ratio is preferably 1.5: 1 and in a particularly preferred manner at least 2: 1 The ratio can then be, for example, 2: 1, 4: 1 or 6: 1. If a lower proportion of ketone and / or aldehyde is used, part of the acetylene does not react to the alkynediol, but the reaction remains for it Part at the level of AI kinmonools, i.e. a 1-substituted or 1, 1-disubstituted propargyl alcohol. In this case, mixtures of Al-kindiol and alkyne monool are obtained. Experience has shown that high amounts of ammonia as a solvent also lead to an increased formation of propargyl alcohol. The volume ratio of ammonia to the ketone or aldehyde used should therefore generally not exceed the value of 30: 1 in order to achieve an optimal yield of pure alkynediols, preferably the value should not be less than 20: 1, in particular that of 10: 1.

It may even be advantageous to fall below the volume ratio of 2: 1 or 1: 1.

If it is desired to produce a mixture of alkyne monool and alkynediol, a higher excess of ammonia, for example a volume ratio to the ketone or aldehyde used of less than 50: 1, preferably less than 40: 1, can be used.

The reaction temperature for the production of pure alkynediols or mixtures with a predominant proportion of alkynediols is generally between 10 ° C. and 140 ° C., preferably between 40 and 120 ° C. and particularly preferably between 50 and 100 ° C. If the temperature is chosen lower, for example below 50 ° C, part of the acetylene does not react to the alkynediol, but the reaction remains for this part at the stage of propargyl alcohol. In this case, mixtures of alkynediol and propargyl alcohol are obtained.

In principle, the process can be carried out at atmospheric pressure or elevated pressure. If ammonia or another volatile substance is chosen as the solvent, it will generally be appropriate to choose the pressure so that the solvent is in liquid form at the reaction temperature. In the case of ammonia as a solvent, a possible suitable pressure is, for example, 20 bar.

The process can be carried out, for example, in such a way that the ketone or aldehyde to be reacted is saturated with acetylene. The alkali compound and the cocatalyst and, if desired, the solvent are then added and the mixture is reacted in a reactor. The reactor used is generally not critical and can be, for example, a tubular reactor, a loop reactor, a stirred tank reactor or a cascade of stirred tank reactors. After the reaction has ended, the mixture can be worked up in a conventional manner. If a volatile solvent is used, this is removed vapors and the product is then obtained, for example, by distillation. The reaction mixture or the residue after removal of the solvent can be freed from the alkali catalyst before washing the product by washing with water and phase separation. Likewise, a possible portion of water in the reaction mixture can be removed by phase separation before removal of a solvent or the recovery of the product if this portion interferes with the further work-up.

Examples

A liquid mixture of acetone with acetylene, liquid ammonia and an hourly 6 ml of a 10 wt. Solution were introduced into a heated tubular reactor (9 mm diameter, 500 mm long), which was operated with a pump as a loop reactor with an external liquid return .-% potassium hydroxide in methanol required. Product was withdrawn from the circuit under pressure control so that the pressure in the reactor was constant at 20 bar. After evaporation of the volatile constituents at room temperature and atmospheric pressure, the product was analyzed by gas chromatography and the amounts of methylbutinol (MBI) and 2, 5-dimethyl-hex-3-in-2, 5-diol (DMHD) produced and the amount of unused acetone was determined. The acetone conversion and the yields of MBI and DMHD were calculated from this.

The results are shown in Table 1.

Examples 1 to 3 show that the method according to the invention makes it possible to prepare the alkynediol with excellent selectivity, that is to say without a measurable amount of alkyne monool.

Examples 4 and 5 show embodiments in which mixtures of the alkynediol and the alkyne monool are obtained.

Example 6 is a comparative example analogous to US Pat. No. 3,082,260, which shows that in the case of a reaction which deviates several times from the procedure according to the invention (too low temperature, too much ammonia and excess acetylene), in accordance with the teaching of US Pat. No. 3 082 260 only the alk - monool is produced.

Table 1: Examples for the preparation of alkynediols

Example No. Temperature Ammonia Acetone / Acetylene ratio Acetone yield Yield

Mixture of acetone / acetylene set at MBI at DMHD

[° C] [ml / h] [ml / h] [Mol / Mol] Mol.- -%] [Mol .-%] [Mol .-%]

1 80 5 60 2 1 32 0 27

2 80 15 60 2 1 44 0 37

3 80 15 60 4 1 50 0 46

4 80 30 30 2 1 77 36 34

5 80 30 30 1 1 79 39 32 6 (comparison) 40 60 30 1 2 92 87 0

Claims

claims

1. A process for the preparation of alkynediols or mixtures of alkynediols with alkyne monools by reacting acetylene with more than equimolar amounts of ketones and / or aldehydes in the presence of an alkali compound, characterized in that the alkali compound in a smaller molar amount than half the molar amount of the ketone and / or aldehyde to be used in the presence of ammonia and / or at least one reactive primary amine.

2. Process for the preparation of alkynediols by reacting acetylene with at least twice the molar amount of ketones and / or aldehydes, characterized in that the alkali compound in a smaller molar amount than half the molar amount of the ketone and / or aldehyde to be reacted in the presence of ammonia and / or at least one reactive primary amine.

3. Process according to claims 1 or 2, characterized in that the alkali compound is used in an amount of 0.1 to 5 mol%, based on the ketone to be reacted and / or the aldehyde to be reacted.

4. The method according to claim 3, characterized in that the alkali compound is potassium hydroxide and / or potassium methoxide.

5. The method according to claims 1 to 4, characterized in that the molar amount of ammonia and / or amine is at least as large as that of the alkali compound used.

6. The method according to claim 5, characterized in that ammonia is used as the solvent.

7. The method according to claim 1, characterized in that the molar ratio of the ketone and / or aldehyde to acetylene is higher than 1.5: 1.

8. Process according to claims 1 to 7, characterized in that the reaction temperature is 10 to 140 ° C.

9. The method according to claims 1 to 8, characterized in that the reaction is carried out under increased pressure.