DE2329145A1 - Tertiary acetylenic alcohols prodn - by reacting ketones with acetylene in liquid ammonia in the presence of alkai catalysts - Google Patents

Abstract

Alcohols of the formula R1R2C(OH)C=CH (where R1 and R2 are alkyl), which are useful as inters. e.g. in the synthesis of highly pure isoprene, various monomers, odorants, pharmaceuticals, vitamins etc. are produced by reacting ketones of the formula R1R2CO with acetylene in liq. ammonia in the presence of a soln. of an alkali catalyst in an aliphatic alcohol at 20-60 degrees C removing the ammonia, neutralising the alkali catalyst, and isolating the end-prod. Using the alkali catalyst in the form of an alcoholic soln. gives homogenous reaction mixts. simplifying the technology of the process. The amt. of catalyst reqd. is reduced, and the reaction can be carried out in the absence of a gas phase, so that the safety of the process is improved.

Description

PROCESS FOR THE PREPARATION OF TERTIARY ACETYLENE ALCOHOLS The present Invention relates to processes for the preparation of tertiary acetylene alcohols.

Tertiary acetylene alcohols come as the most important starting product in several areas of chemical production, e.g. in the synthesis of highly pure Isoprene, various monomers, fragrances, drugs, vitamins, etc. Use.

Processes are known for the production of tertiary acetylene alcohols by reacting acetylene with ketones in the presence of alkali catalysts in liquid ammonia, which can generally be represented by the following formula: wherein R11 R2 are identical or different alkyl substituents.

A process for the production of dimethylethynyl carbinol is known by reacting ketones with acetylene (see Sect.

USSR copyright certificate No. 186449).

Alkali hydroxides in the form of their aqueous solutions serve as catalysts.

The reaction mixture is obtained by adding acetylene below 0.4 at Upper pressure in the acetone-ammonia mixture cooled to a temperature of -45 to -50 ° C solves. The mixture obtained is placed in a reactor equipped with a stirrer abandoned, in which the aqueous catalyst solution in an amount of 5 wt.%, based on the ketone weight, the same tig is introduced. The reaction takes place at a temperature between -40 and + 400C. After the reaction has ended, throttles the mixture obtained and drives off the Sm-ammonia therefrom, after which the im Catalyst present in the reaction mixture is neutralized. Isolating the end product, of Dimethyläthinylkarbinols, is z .B by a known method. through rectification, realized.

The method has the disadvantage that the technological process is complicated is because there is megen formation of the heterogeneous Starting reaction mixture is necessary to carry out an intimate forced mixing and thus an apparatus to be used with a screen motor.

The purpose of the present invention is to eliminate the above Disadvantage.

The invention is based on the object Arbeitsbedingungen.im Process for the production of tertiary acetylene alcohols of the general formula R1R2C (OH) C = CH, in which the same or different alkyl substituents are, by reaction of Ketones of the general formula R1R2C = O, in which R1, R2 are identical or different alkyl substituents mean with acetylene in aqueous ammonia in the presence of an alkali catalyst at an elevated temperature with subsequent ammonia removal as a result change so that the alkali catalyst present in the reaction mixture is neutralized and isolate the final product.

According to the invention, this object is achieved in that the implementation of ketones with acetylene between 20 and 60 ° C takes place, while the catalysts mentioned in the form of an alcoholic solution thereof in aliphatic alcohol for use come.

By using alcoholic solutions of alkali catalysts, which dissolve in the mixture of liquid ammonia and ketone, a reaction mixture forms, which is a common solution or permanent emulsion.

If the starting ketone dissolves in liquid ammonia ni @@ t.

so the aliphatic alcohol is added to dissolve the ketone in liquid ammonia is necessary.

If the end product is insoluble in water, it is advisable to add the reaction mixture to wash with water instead of neutralizing after the ammonia expulsion.

Aliphatic alcohols containing 1 to 6 carbon atoms can be used Alcohols as well as acetylene alcohols produced by the reaction are for use come.

Carrying out the process under homogeneous conditions according to the method according to the invention in comparison with the known makes it possible to simplify the technological process significantly. It's a lower consumption of catalyst is required, and thus a smaller amount of neutralizing agent is required consumed. The selection of alkali catalysts in the process of the invention is also significantly larger because alcoholic solutions of the same are used. The reaction can be carried out even more under conditions if the mixture completely fills the reactor and does not form a gas phase. Because of the absence of the The operational reliability of the process is increased in the gas phase.

The method according to the invention is carried out as follows.

The process can be carried out either continuously or periodically will.

The starting reaction mixture is obtained by adding acetylene under about 0.4 at overpressure in the cooled to a temperature of -45 to -50 ° C Ketone-ammonia mixture dissolves.

You take starting ingredients, starting from about 1 mole of acetylene each 2.5 to 4 moles of ammonia and 1 mole of ketone. The mixture obtained is sent to the reactor at the same time supplied with alcoholic catalyst solution. The alcoholic catalyst solution can also use the starting mixture of ammonia and ketone before its saturation with acetylene can be added.

In the other embodiment, all of the starting ingredients and the alcoholic catalyst solution to the reactor immediately without prior preparation of the starting reaction mixture are supplied.

The reaction takes place between 20 and 600 C at increased pressure (20 up to 30 atm) for 5 to 60 minutes. The degree of conversion of ketone reaches 70 up to 95%. After the reaction has ended, the mixture obtained is throttled to atmospheric pressure, drives off ammonia, which is fed back into the process, neutralizes the in the reaction mixture existing alkali catalyst or washes the reaction mixture with water then, when the end product is insoluble in water. The unreacted, by distillation isolated, ketone is also returned to the process.

The reaction mixture from the reactor can be without any Repeatedly saturate the treatment with acetylene at a temperature of -45 to -500C and feed it back into the process, thereby increasing the degree of conversion of ketone increased without the acetylene content of the starting mixture sunimmlt, which increases the explosion safety of the process increases.

The reaction can be carried out under conditions when the mixture completely fills the reactor and does not form a gas phase. In the absence of the Gas phase in the reactor, the operational reliability of the process is also increased.

For a better understanding of the present invention, the following are made specific examples given, Example 1 The starting reaction mixture is obtained by dissolving 6.5 kg of acetylene under 0.4 atm overpressure in the mixture, the 12 kg of acetone and 13.5 kg of liquid ammonia and at a temperature of -45 to -500C has cooled down. The reaction mixture is fed continuously to the reactor, in the catalyst, namely 42 g of KOH, dissolved in 560 g of dimethylethynyl carbinol, arrived at the same time. The reaction takes place at 55 ° C. for 17 minutes. After finished Reaction throttles the resulting mixture to atmospheric pressure, drives ammonia from it, neutralizes the alkali catalyst that is present in the mixture, and isolates dimethylethynyl carbinol by rectifying the mixture. You get 10.44 kg product, i.e. 60.7%, based on the acetone taken.

Example 2 The reaction mixture, which 1 mole of acetone, 3.7 moles of liquid Ammonia, 1 mole of acetylene and 5 g of caustic potash in 20 g of ethyl alcohol is used in the reactor heated at 600 C for 8 minutes. According to the indications of the chromatographic analysis the degree of conversion of dimethylethynylcarbinol is 82%.

Achieved when replacing caustic potash with alcoholate in ethyl alcohol the degree of conversion 95%.

Example 3 The reaction mixture which contains 1 mol of methylheptenone, 4 Mole of liquid ammonia, 1 mole of acetylene, 5 g of caustic potash in 20 g of methanol contains heated in the reactor at 550 C for 10 minutes. According to the chromatographic Analysis shows the degree of conversion of methylheptenone into 2,6-dimethyloctene-2-yn-7-ol-6 95%.

Example 4 The reaction mixture, which 1 mole of acetone, 4 moles of liquid Ammonia, 1 mole of acetylene and 1.2 g of (CH3) 4NOH in 5 g of methanol is added to the reactor heated at 470 C for 8 minutes. The degree of conversion, based on the acetone, is 45 5 '.

Example 5 to 7 When the reaction mixture is heated from the im Example 4 specified composition in the presence of 2.7 G; possibly% (CH3) 4NOCH3 as 20% strength methanol solution, the yield of dimethylethynyl carbinol was 95%. In the Use 3.5% by weight (CH3) 4NO (n-C3H7) as a catalyst (in the form of a 20% solution in n-C3H7OH) the yield of dimethylethynyl carbinol was 66%. Used as a Catalyst 2.7% C6H5CH2N (CH3) 3 OH in the form of its 20% solution in isopropyl alcohol, the yield of dimethylethynyl carbinol is 97%.

Example 8 The reaction mixture consisting of 0.3 mol of liquid Ammonia, 0.155 mole acetylene, 21.4 g (0.1 mole) 2,6-dimethyldekanon-10 and 0.5 caustic potash in 10 g of isopropyl alcohol, was heated at 260C in the reactor for 40 minutes. According to the results of the chromatographic analysis, the content of 2,6,10-trimethyldodecine-11-Cl-10 is 92.4%.

Example 9 The reaction mixture consisting of 0.3 mol of liquid Ammonia, 0.155 moles of acetylene, 0.1 moles of 2,6,10-trimethylpentadecano-14, 0.5 g of caustic potash in 15 g of isobutanol, was heated at 250C in the reactor for 1 hour. After the According to the chromatographic analysis, the content of 2,6,10,14-tetramethylhexadecine-15-ol-14 is 91.7%.

Claims (3)

PATENT CLAIMS: 1. Process for the production of tertiary acetylene alcohols general formula R1R2C (OH) C = CH, where R1 and R2 are identical or different alkyl substituents are, by reaction of ketones of the general formula R1R2C, O, where R2 is the same or means different alkyl substituents with acetylene in liquid ammonia in the presence of an alkali catalyst at elevated temperature with subsequent Removal of ammonia by neutralizing an alkali catalyst present in the reaction mixture and isolating the final product that does not indicate that the Reaction of ketones with acetylene between 20 and 60 ° C takes place while the catalyst in the form of an alcoholic solution of the same in aliphatic alcohols for use comes. 2. The method according to claim 1, d a d u r c h g ek e n n z e i c h n e t that in the case where the ketone is insoluble in liquid ammonia, the aliphatic one Alcohol is added in which said ketone is soluble. 3. The method according to claim 1, 2, d a d u r c h g e -k e n n z e i c h n e t that in the event that the end product is water-insoluble, the reaction mixture is washed with water after removal of ammonia.