DE738400C - Process for the production of polyketones, ketocarboxylic and polycarboxylic acids - Google Patents

Description

Process for the preparation of polyketones, ketocarboxylic acid and polycarboxylic acid derivatives It has long been known that acetoacetic esters and analogously constituted compounds with reactive methylene hydrogen can be added to α-β-unsaturated ketones or carboxylic acid esters with the establishment of the double bond. Such reactions have hitherto mostly been carried out in solvents, preferably in ether, the compound to be deposited being used wholly or largely as a sodium compound (cf., for example, Decombe, Comptes rendus, Volume 205, 1937, p. 68o).

As has now been found, the addition of such compounds with reactive methylene hydrogen to unsaturated compounds of the general composition where R1 = H, alkyl or aryl, R2 = double-bonded oxygen, R3 - is alkyl, aryl or o-alkyl and R3 -f- R, can also be - N, that is to say more corresponding to vinyl ketones or to alkyl esters or to the nitriles Vinylcarbonic acids can be achieved in a technically very simple manner and with good yields by heating the free compounds together to a higher temperature. The reaction can be accelerated considerably by adding small amounts of catalytically active alkalis. Without this addition, the reactions are basically the same, but much more slowly, so that it is always worthwhile to allow them to take place with the addition of these small amounts of basic substances. Likewise, in order to avoid secondary conversions and associated losses, it then appears advisable to neutralize these basic additives before working up. The reaction takes place, especially in the a-position unsubstituted vinyl ketones and acrylic acid derivatives, with the release of considerable heat of reaction, so that it is advisable not to add these compounds all at once, but gradually according to the heat of reaction removed. Surprisingly, despite the relatively high reaction temperatures, there is no significant thermal polymerization of the vinyl compounds.

The partly known, obtainable by the present process partly new connections offer technical exploitation possibilities in different directions.

EXAMPLE I 26o parts of acetoacetic ester are admixed with a solution of 0.5 parts of potassium hydroxide in 3 parts of gasoline, the mixture is heated to about 60 ° and about 30 parts of vinyl methyl ketone are run in with stirring. The increase in temperature that occurs is moderated by external cooling, and during the further addition of 10 parts of vinyl methyl ketone, the temperature is kept between 60 and 85 ° at the end at about 100 ° a little sulfuric acid and the mixture is then distilled under reduced pressure. After about 60 parts of first run, predominantly a mixture of the starting compounds, about 28o parts under g mm at 145 to 154 'are obtained, while remain.

The main product, which mainly boils under pressure at 150 'and cg, is 3-carb = ethoxyheptanedione-2-6. EXAMPLE 2 39o parts of acetoacetic ester are mixed with a solution of 1 part of potassium hydroxide in 3 parts of alcohol, and 258 parts of methyl acrylate are gradually added with stirring at 10 ° to 130 ° over the course of about 1/2 hour. Appropriate cooling ensures that the heat of reaction is dissipated. After stirring for 2 hours at 125 ° and neutralization with sulfuric acid, the mixture is distilled under reduced pressure. The main product boils at 135 to 145 ° under 5 mm pressure and is et @ "- a 500 parts. If instead of the ethyl acrylate z. If, for example, the butyl acrylate reacts, the butyl ester of i-acetyl-i-carboxethylbutyrate is obtained under very similar conditions and boiling at 16o ° at 7 mm pressure.

EXAMPLE 3 300 parts of acetylacetone are heated to 100 ° with stirring, after 2 parts of potassium hydroxide have been added, and 2io parts of vinyl methyl ketone are gradually added in such a way that the temperature rises to about 126 ° C. The mixture is then stirred for 2 hours at i20, neutralized and distilled under reduced pressure. About 35o parts of 3-acet \ -1-lieptandione-2, 6 are obtained, which transitions between 135 and 150 ° under 12 mm Di-1, 7k. In addition, about 50 parts of a product that fades at 17 ° to 1850 ° and 12 mm pressure is obtained, which solidifies on cooling and crystallizes from alcohol in colorless needles with a melting point of 150 °. This product results from the addition of two molecules of vinyl methyl ketone to one molecule of acetylacetone. According to the analysis, it represents a condensation compound formed from it by the escape of 1 molecule of water, which probably has the following composition Example: 32o parts of malonic ester are heated to 100 ° and 172 parts of methyl acrylate are run in over the course of 3 hours. The mixture is gradually warmed to 120 ° and finally stirred for 5 hours at this temperature. It is now distilled under reduced pressure. After a short run, the main product passes between 150 and 170 degrees at 5 mm pressure with over 80 ″ yield of the ethyl ethyl ester of z-carbethoxyglutaric acid. Example s 495 g of methyl cyanoacetate are heated to 85 ° after the addition of 3 g of piperidine. While cooling, @ 35o g vinyl methyl ketone are added over the course of 20 minutes. The temperature is allowed to rise to 100 ° and the mixture is finally kept at 130 ° for 3 hours. When working up, the main product obtained is; - Acetyl-x-cyanobutyric acid ethyl ester. Example 16 After addition of 5 g of morpholine, 65o parts of acetoacetic ester are heated to 120 ° and 265 parts of acrylonitrile are allowed to run in over the course of 20 minutes with cooling. In the subsequent vacuum distillation, the γ-acetyl-γ-carbätlioxybutyronitrile boiling at 140 to 148 ° at 5 mm pressure is obtained with a 40% yield. Furthermore, with a yield of 350 /, a product is obtained which boils at aooo and 5 mm pressure, which solidifies in colorless needles on cooling which, after recrystallization from alcohol, have a melting point of 82.5 °. According to the analysis, they represent the addition of 2 molecules of acrylonitrile to one molecule of acetoacetic ester. Example 7 32o parts of malonic ester are heated to 100 after adding 3 g of potassium hydroxide in 10 g of methanol. Without cooling, zoo parts of methyl methacrylate are added over the course of 3 hours. The mixture is heated more and more intensely and at the end stirred for a further z hours at 140 °. It is then neutralized and distilled under reduced pressure. Almost without. The flow passes over at a pressure of between 1.5 and 1700 at a pressure of 5 mm, with a yield of 80 '/ o of the ethyl methyl ester of z-carbethoxy [methylglutaric acid]. EXAMPLE 8 39o parts of acetoacetic ester are heated to 10 'after adding a solution of 3 g of potassium hydroxide in 10 g of fuel; 300 parts of methyl methacrylate are added over the course of 1 hour. The mixture is continuously heated so that it boils evenly. It is now boiled on the reflux condenser for about 5 hours until the temperature has risen to 160 °. In the subsequent vacuum distillation of the weakly acidic solution, about 30% of the starting compounds are recovered unchanged. After a short intermediate run, the 2-ketohexane-3,5-dicarboxylic acid methyl ether is obtained in a yield of about 650%, based on the compounds used. Example 100 parts of acetylacetone are heated to 80 ° after adding a solution of ig sodium hydroxide in 3 g of fuel. 132 parts of phenyl vinyl ketone are added dropwise over the course of hours; the heating is switched off while the drops are being added. The mixture is then stirred at 80 ° for 1 hour and at 10 ° for a hour. When the acidified mixture is distilled under reduced pressure, after a short preliminary run - mainly an unchanged mixture of the starting compounds - 150 parts of a thick oil which boils at 150 ° under 3 mm pressure and soon solidifies in deep yellow crystals. After recrystallization, these show a melting point of 81 °. According to the analysis, they represent a product created by the leakage of water from the initially formed addition compound according to the following scheme:

Claims (1)

PATENT CLAIM: Process for the production of polyketones, ketocarboxylic acid and polycarboxylic acid pellets by reacting compounds with reactive methylene hydrogen, such as acetoacetic ester, and analogously constituted compounds with unsaturated compounds of the general composition where R1 = H, alkyl or aryl, R2 = double-bonded oxygen, R3 = alkyl, aryl or o-alkyl and R2 + R3 can also be - N, with heating, characterized in that this reaction is carried out in the absence of solvents and if necessary, in the presence of small amounts of basic substances, which are neutralized when using fixed alkalis before work-up.