DE2429937A1 - PROCESS FOR THE PREPARATION OF 2,2,6,6TETRAMETHYL-4-OXO-PIPERIDINE - Google Patents

Description

Process for the preparation of 2,2,6,6-tetramethyl-4-oxopiperidine

The production of 2,2,6,6-tetramethyl-4-oxo ~ piperidine is already known. It consists in the fact that oian 2.2, 4,4,6-Pentamethyl-2,3,4,5-tetrahydropyriiiiiiidin with a Lewis acid, preferably zinc chloride or calcium chloride in the presence of water. This as the starting material Usable pyrimidine derivative can be prepared from acetone and ammonia, its isolation from the reaction medium and, if necessary, cleaning, however, requires a considerable amount of work.

Attempts have also been made to find both reaction

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to combine steps i.e. the production of 2,2,6,6-tetramethyl-4-oxopiperidine to be realized directly from acetone without isolating the pentamethyltetrahydropyrimidine. Appropriate Attempts have so far not produced satisfactory yields, reaction mixtures are formed which are difficult to separate is lossy.

It has now been found, surprisingly, that, provided certain process conditions are observed, directly can produce 2,2,6,6-tetramethyl-4-oxopiperidine from acetone in good yield and purity. The procedure persists from two procedural steps, which can be carried out immediately one after the other, so that it is particularly suitable for the large-scale technical Production of tetramethylpiperidone is suitable. The method according to the invention is characterized in that man

a) acetone with ammonia in the presence of 0.2 to 12 mol%, based on the acetone used, of an acidic catalyst at 5 to 60 ⁰ C and reacts

b) the reaction with or without the addition of further acetone is completed by further heating, the Total amount of acetone used in the reaction to the amount of ammonia used in a molar ratio of is equal to or greater than 1.6: 1.

In the first stage of the process, preferably at least 0.15 moles of ammonia is left with the acetone react, but for practical reasons it is more appropriate to 'saturate the reaction mixture with ammonia; therefore will an excess of ammonia is preferred.

Either a Lewis acid such as aluminum chloride or tin tetrachloride can be used as the catalyst or - preferably - boron trifluoride or a boron trifluoride adduct; or a protic acid is used, or the salt of a protic acid with ammonia or a nitrogen-containing one organic base, in particular a primary, secondary or tertiary nitrogen base.

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Examples of such protic acids or of acid components in salts used as acidic catalysts are in particular: mineral acids, such as hydrochloric acid, hydrobromic acid, hydrogen iodide

acid, nitric acid, sulfuric acid and phosphoric acid, as well Sulphonic acids, such as aliphatic or aromatic sulphonic acids, e.g. methanesulphonic acid, benzenesulphonic acid, p-toluenesulphonic acid or naphthalene sulfonic acid, phosphonic acids and phosphinic acids, such as aliphatic or aromatic, e.g. methyl, benzyl or Phenylphosphonic acid, or dimethyl, diethyl or phenylphosphinic acid, and carboxylic acids, such as monobasic, dibasic or tribasic aliphatic or aromatic carboxylic acids, e.g. saturated or unsaturated monobasic aliphatic carboxylic acids with 1-18 carbon atoms, such as formic acid, acetic acid, Chloroacetic acid, dichloroacetic acid, trichloroacetic acid, propionic acid, Butyric acid, lauric acid, palmitic acid, stearic acid, Acrylic acid, methacrylic acid and cinnamic acid, saturated and unsaturated dibasic aliphatic carboxylic acids such as oxalic acid, Malonic acid, succinic acid, adipic acid, sebacic acid, tartaric acid, malic acid, fumaric acid and maleic acid, tribasic aliphatic carboxylic acids, such as citric acid, monobasic aromatic carboxylic acids, such as substituted or unsubstituted Benzoic acid and naphthoic acid, and aromatic dibasic Carboxylic acids such as phthalic acid and terephthalic acid. Monobasic and dibasic aliphatic or aromatic are preferred Carboxylic acids and monobasic aromatic sulfonic acids, such as acetic acid, succinic acid, maleic acid, benzoic acid, o-iodobenzoic acid, m-methy! benzoic acid, p-tert.-buty! benzoic acid, p-toluenesulfonic acid and cinnamic acid. As organic bases are

0 9 8 8 3/1 3 hours

suitable: aliphatic, alicyclic and aromatic, primary, secondary and tertiary amines, saturated and unsaturated nitrogen bases, urea, thiourea and basic ion exchange resins. So are aliphatic, primary amines e.g. methylamine, ethylamine, n-butylamine, octylamine, dodecylamine and hexamethylene diamine, aliphatic secondary amines e.g. dimethylamine, diethylamine, di-n-propylamine and di-isobutylamine, aliphatic tertiary amines e.g. triethylamine, 'alicyclic primary amines e.g. cyclohexylamine, aromatic primary amines e.g. aniline, Toluidine, naphthylamine and benzidine, aromatic secondary amines e.g. N-methylaniline and diphenylamine, aromatic tertiary amines Amines e.g. N, N-diethylaniline, saturated and unsaturated nitrogen bases e.g. heterocyclic bases e.g. Pyrrolidine, Piperidine, N-methyl-2-pyrrolidone, pyrazolidine, piperazine, pyridine, Picoline, indoline, quinuclidine, morpholine, N-methylmorpholine, 1,4-Diazabicyclof_2,2,2 _] - octane and triacetonamine, urea, Thiourea and strongly and weakly basic ion exchange resins. Acetonine and diacetonamine and are also preferred Triacetone amine. Examples of preferred salts are: cyclohexylamine formate, Pyridine formate, pyridine p-toluenesulfonate, di-nbutylamine acetate, Di-n-butylamine benzoate, morpholine succinate, Morpholine maleate, triethylamine acetate, triethylamine succinate, Triethylamine maleate, aniline acetate, triacetonamine p-toluenesulfonate and acetonine hydrochloride.

Ammonium chloride or boron trifluoride or a mixture of both compounds are particularly preferred.

These catalysts are used in an amount of 0.2 to 12 mol%, based on the acetone used, preferably use 2-5 mol%.

As an additional co-catalyst you can use: potassium iodide, Sodium iodide, lithium bromide, lithium iodide, lithium rhodanide,

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Ammonium rhodanide, lithium cyanide, lithium nitrate, ammonium sulfide, bromine, iodine, or a bromide, iodide, nitrate, methanesulfonate, "benzenesulfonate or p-toluenesulfonate of ammonia, triethylamine, urea or thiourea, for example in amounts of 0.01 to 0.5 mol -7 _O based on acetone.

The reaction temperature is in the first step 5 to 60 ⁰ C, preferably 5 to 35, particularly preferably 5 to 25 ° C. The addition of a monofunctional or polyfunctional alcohol has proven to be advantageous in the first process stage. Examples of alcohols suitable for this purpose are methanol, butanol, cyclohexanol, benzyl alcohol, ethylene glycol, diethylene glycol, propylene glycol, ethylene glycol monoethyl ether or 2-ethylhexanol. Preference is given to using lower monoalcohols such as methanol, ethanol and isopropanol, of which methanol is particularly preferred.

The reaction time of this first process stage, which takes place at low temperature, is at least 1, preferably 3 hours.

■ One variant of the procedure is as follows:

Subsequent to this first step of the process, a larger amount of acetone and / or a greater amount of acetone is added to the reaction medium Add diacetone alcohol or mesityl oxide or Phoron or diacetonamine or triacetonediamine and increase the temperature, preferably to 40 to 65 ° C. In the usual case, acetone is added, specifically in an amount of at least 0.5, especially 1 Parts, preferably 2-4 parts per part of the initial amount of acetone used. Just like acetone, the Use acetone derivatives listed above, preferably

409 8.8 3/136 b

Diacetone alcohol or its mixture with acetone. Farther it can be beneficial in this second procedural stage to add further catalyst to the reaction medium. this can be used together with the addition of acetone or acetone derivative happen or a little later. The same substances as in the first process stage are suitable as catalysts, boron trifluoride, ammonium chloride, concentrated sulfuric acid or hydrogen chloride.

The reaction time required for the second process stage, which takes place at an elevated temperature, is about 3 to 20 hours.

Also the following method step is advantageous for guiding b) 8-20 hours at 50-55 ⁰ C, or at first 2-7 hours at 50-55 ⁰ C and then for another 2-6 hours at reflux temperature, in particular at about 56-60 ⁰ C.

Both process stages can be carried out under pressure, e.g. 1-30, especially 1-10, especially 1-3 atmospheres overpressure. In this case, temperatures above 60 ° C are possible.

The tetramethylpiperidone can be isolated in a manner known per se, e.g. by adding water and separating as a hydrate, or by adding acid such as hydrochloric acid, sulfuric acid or oxalic acid and separating as salt, or by adding an excess of lye, in particular concentrated alkali, such as aqueous sodium hydroxide solution or potassium hydroxide solution, and separation as an organic layer, or in particular by distillation, if necessary after neutralization of the catalyst by adding a base such as sodium hydroxide, potassium hydroxide or sodium carbonate.

The acetone used in the first stage of the process can, to a certain extent, be water and / or condensation products of acetone, such as diacetone alcohol, mesityl oxide,

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Contain phoron, diacetonamine and / or triacetonediamine. Such an addition can have a favorable effect on the yield. A preferred condensation product of acetone is mesityl oxide and especially diacetone alcohol. This makes it possible to use the distillate resulting from distillative work-up at the end of the second stage as raw material in the first stage, which results in a high acetone conversion. If the water content of the reaction medium increases, e.g. in the case of such a medium Recycling too much, it is advisable to remove some of the water from the reaction mixture. This can for example, by adding concentrated alkali, e.g. sodium hydroxide solution, to the reaction mixture at the end of the first stage. is added and, after brief stirring, the aqueous layer is separated off.

In the method according to the invention can also organic solvents can be used.

Organic solvents which are particularly suitable for the process according to the invention are, for example, hydrocarbons, such as aromatics, e.g. benzene, toluene and xylene, as well as aliphatics such as hexane, heptane and cyclohexane, as well as chlorinated hydrocarbons, such as methylene chloride, trichloroethane, carbon tetrachloride, Chloroform, ethylene chloride and chlorobenzene, and ethers such as tetrahydrofuran, dioxane and diethyl ether, and nitriles such as Acetonitrile, as well as aprotic polar solvents such as suIfolan, acetonitrile, nitromethane, dimethylformamide, dimethylacetamide, Tetramethylurea, hexamethylphosphoric acid amide and dimethyl sulfoxide, and particularly preferably alcohols, such as mono- or polyfunctional, unsubstituted or substituted aliphatic ones Alcohols, e.g. lower alkanols such as methanol, ethanol, propanol, isopropanol and tert-butanol, as well as cyclohexanol, benzyl alcohol, Ethylene glycol monomethyl ether, glycol and propane-1,3-diol,

409883/136 b

especially a C-, -C, -alcohol, such as methanol, as well as diacetone alcohol, Phoron, Diacetonamine, Triacetonediarain and Mesityloxide. Mixtures of the above solvents are also suitable.

The present invention is illustrated by the following examples. Further advantageous refinements of the method according to the invention can be seen from the patent claims.

409883/136

example 1

A suspension consisting of 11 g of ammonium acid and a mixture of 340 g of acetone and 64 g of methanol is saturated with ammonia gas at 13 to 17 ° C. for 12 hours. Subsequently X'jird diluting the resulting colorless oil with 350 g of acetone and 15 to 20 Sttinden kept under stirring at 50-55 C ^p long. Excess solvent is then removed by evaporation in vacuo and 36 g of water are added to the reddish residue. The crystallization, which begins at 0 to 5 ° C., is completed by stirring for 2 hours. 286 g of 2,2,6,6-tetramethyl-4-oxopiperidine hydrate of melting point 55 ° -60 ° C. are obtained in the form of pale yellowish crystals. . ·

The product is obtained as the oxalate salt from the decomposition point 180 ⁰ Cj when neutralizing the Reakticnsmischung with oxalic acid.

Example 2

The procedure is as indicated in Example 1, with the difference that in the 2nd step together with the addition of acetone 1.3 g of boron trifluoride, dissolved in ether, is added. Isolation of 2,2,6,6-tetramethyl-4-oxopiperidine takes place as described in example!

• 409883/1 385

Example 3

The procedure is as in Example 1, with the difference that instead of ammonium chloride, 1.3 g of boron trifluoride, dissolved in ether. In the second process step, 11 g of ammonium chloride are then added together with the Acetone added to the reaction mixture.

Example 4-7

A suspension consisting of 11 g of ammonium chloride, 340 g of acetone and 64 g of methanol is saturated with aramonia gas for 4 hours at 13 to 17 ° C. Subsequently, the resulting colorless oil is diluted with 900 g acetone and held for 15 to 20 hours with stirring at 50-55 ⁰ C. After the first 6 hours, 70 g of 97% sulfuric acid are added dropwise to the solution within 1-2 hours. At the end of the reaction time, the pH of the reaction mixture is adjusted to a value of 4.5 to 5 within 1-2 hours using 97% strength sulfuric acid. The resulting suspension of the hydro-sulfate of 2 _{J-TetrameLhyl} 2,6,6-4-oxopiperidine is filtered at 5-10 ⁰ C and washed with acetone. 655 g of hydrosulfate salt are obtained, which corresponds to 381 g of 2,2,6,6-tetraraethyl-4-oxopiperidine.

Proceed as described above, but in the 2nd step the amount of acetone and acetone given in Table 1 If sulfuric acid is used, that in the third is obtained Yields indicated in the column of the table.

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-Λί -

example Acetone henge
in the 2nd step Sulfuric acid-
Amount (after 6
Hours added) yield
2,2,6,6-tetra
methyl-4-oxopi-
peridin 100%
(isolated as
Hydrosulphate) 5 900 g - 342 g 6th 1140 g 70 g 402 g 7th 670 g 45 g 314 g

Example 8

A suspension consisting of 11 g of ammonium chloride, 340 g of acetone and 64 g of methanol is saturated with ammonia gas for 4 hours at 13 to 17 ° C. The resulting colorless oil is then diluted with 900 g of acetone and kept at 50-55 ° C. for 15 to 20 hours with stirring. After the first 6 hours, the pH of the solution is adjusted to 8.5-8.6 by introducing about 23 g of hydrogen chloride gas. At the end of the reaction time, the pH of the reaction mixture with hydrogen chloride increases within 1-2 hours set to the value 5 to 6. The resulting suspension of the hydrochloride of 2,2,6,6-tetramethyl-4-oxopiperidine is at - · * filtered 0-5 ⁰ C and washed with acetone. 400 g of hydrochloride salt are obtained, which contains 293 g of 2,2,6,6-tetramethyl

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-ΛΖ -

4-oxopiperidine corresponds.

After distilling off Hr, 0 and methanol and diluting the distillation residue are made from the mother liquor with acetone a further 95 g of Hydrochloric !, which contains 70 g of 2,2,6,6-tetramethyl-4-oxopiperidine corresponds, isolated.

Example 9

40 g of ammonia gas are introduced into a mixture consisting of 126 g of acetone, 22.5 g of methanol and 4.7 g of ammonium chloride in about 4 hours at 13-15 ° C. The reaction mixture is then stirred for a further 30 minutes at the same temperature. Are then added 220 g of diacetone alcohol and 110 g of acetone to the reaction mixture, the whole is heated within 1 hour to '55 ⁰ C and holding it for 12 hours at this temperature. Working up the experiment by fractional distillation gives 125 g of 2,2,6,6-tetramethyl-A-oxopiperidine.

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Example 10

A suspension consisting of 11 g of ammonium chloride, 340 g of acetone and 64 g of methanol is saturated with ammonia gas at 13 to 17 ° C. for 4 hours. Subsequently, the resulting colorless oil is diluted with 900 g acetone and held for 15 to 20 hours with stirring at 50-55 ⁰ C.

According to the gas chromatogram, the resulting reaction mixture contains 378 g of 2,2,6,6-tetramethyl-4-oxopiperidine (Triacetonamiri), which is isolated by distillation.

Example 11

A suspension of 11 g of ammonium chloride, 340 g of acetone and 4 g of 20% strength aqueous solution of ammonium sulfide is saturated with ammonia gas ^{at 13 to 17 ° C. for 4 hours.} Then continue as indicated in example 10.

The final reaction mixture contains 450 g of triacetonamine.

Example 12

A suspension of 11 g ammonium chloride, 340 g Acetone and 1 g of potassium iodide are saturated with ammonia gas for 4 hours. Then continue as in example 10 is specified. The reaction mixture contains 400 g of triacetonamine. ■

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- 14 ■
Example 13

The procedure is the same as in Example 10, except that 64 g of dioxane are used instead of 64 g of methanol. The reaction mixture contains 314 g of triacetonamine.

Example 14

The procedure is the same as in Example 10, except that 64 g of ethanol are used instead of 64 g of methanol. The reaction mixture contains 363 g of triacetonamine.

Example 15

The procedure is the same as in Example 10, except that 64 g of isopropanol are used instead of 64 g of methanol.

• The reaction mixture contains 350 g of triacetonamine,

Example 16

The same result as in Example 15 is obtained when the methanol is replaced by 64 g of dimethylformamide replaced.

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Example 17

The procedure is the same as in Example 10, but without the addition of methanol.

The reaction mixture contains 336 g of triacetonamine.

Example 18

A suspension consisting of 11 g of ammonium chloride, 340 g of acetone and 64 g of methanol is used for 4 hours saturated with ammonia gas at 13 to 17 ° C.

Subsequently, the resulting colorless oil is diluted with 1,360 g of acetone and maintained for 15-20 hours under stirring at 50-55 ⁰ C.

The resulting reaction mixture contains 420 g of triacetonamine.

Example 19

Same as Example Io, the procedure is, however, first for 6 hours at 50-55 ⁰ C and then for 3 hours under vigorous reflux is stirred (at-56-60 ⁰ C) after dilution with 900 g of acetone.

The resulting reaction mixture contains 337 g of triacetonamine.

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- 16 Example 20

The procedure is the same as in Example 10, except that 5.5 g or 38 g are used instead of 11 g of ammonium chloride Amiiionium chloride used:

Ammonium chloride
G g triacetonamine
in the reaction mixture 5.5 220 38 381

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Claims (1)

Claims dr er le N D dinne _ PATENT ADVOCATE 2 8 B F? E M E N UHLANDSTRASSE . Process for the production of 2,2,6,6-tetramethyl 1-4-oxopiperidine, characterized in that one a) acetone with ammonia in the presence of 0.2-12 mol-7 ₀ based on the acetone used an acidic catalyst at 5-60 ⁰ C, and b) the reaction with or without the addition of further acetone completed by further heating, the total amount of acetone used in the reaction to the used Amount of ammonia in a molar ratio of equal to or greater than 1.6: 1. 2. The method according to claim 1, characterized in that the acetone in process step a) partly by diacetone alcohol and / or mesityl oxide is replaced. 3. The method according to claim 1, characterized in that partially or completely through the acetone in process step b) Diacetone alcohol, mesityl oxide, Phoron, diacetonamine or triacetonediamine is replaced. 4. The method according to claim 2, characterized in that the acetone is partially replaced by mesityl oxide. 5. The method according to claim 3, characterized in that some or all of the acetone is replaced by diacetone alcohol, 6. The method according to claim 1, characterized in that the total amount of acetone used in the reaction to the used Amount of ammonia in a molar ratio of 2 ρ 6: 1. .409883 / 1365 7. The method according to claim 1, characterized in that in process step a) acetone and ammonia in a molar
Ratio of 0.8-1.1: 1 used, and the rest
Acetone is used in process step b). 8. The method according to claim 1, characterized in that the salt of a protic acid is used as the acid catalyst
Ammonia or a nitrogen-containing organic base is used. 9. The method according to claim 8, characterized in that the protic acid is a mineral acid or an organic one
Acid used. 10. The method according to claim 9, characterized in that the organic acid is a sulfonic acid or a carboxylic acid
used. 11. The method according to claim 8, characterized in that the ammonium salt of a mineral acid is used as the salt. 12. The method according to claim 8, characterized in that the ammonium salt of an organic acid is used as the salt. 13. The method according to claim 8, characterized in that the salt is a mineral acid salt of a nitrogen-containing
organic base is used. 14. The method according to claim 8, characterized in that the salt is a salt of a nitrogen-containing organic base
used with an organic acid. 409883 / 136b 15. The method according to claim 8, characterized in that triacetonamine is used as the nitrogenous organic base, Triethylamine, hexamethylenediamine, 1,4-diazabicyclo [2,2,2] octane, Urea or thiourea ends. 16. The method according to claim 8, characterized in that a salt of hydrochloric, hydrobromic or hydrochloric acid, of nitric acid, an organic sulfonic acid, cyanoacetic acid, or a haloacetic acid is used. 17. The method according to claim 8, characterized in that an ammonium salt of hydrochloric acid, hydrobromic acid, Hydroiodic acid, nitric acid, benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, dichloro or Cyanoacetic acid used. 18. The method according to claim 8, characterized in that a salt of hydrochloric acid, hydrobromic acid, Hydriodic acid, nitric acid, benzenesulfonic acid, p-toluenesulfonic acid, Methanesulfonic acid, dichloroacetic acid or cyanoacetic acid with triacetonamine, triethylamine, hexamethylenediamine, 1,4-diazabicyclo [2.2.2] octane, urea or thiourea used. 19. The method according to claim 8, characterized in that the salt is ammonium chloride, ammonium bromide, ammonium iodide, Ammonium formate, ammonium tosylate, urea nitrate, urea tosylate, Hexamethylenediamine dihydrochloride or triacetonamine hydrochloride used. 20. The method according to claim 8, characterized in that hexamethylenediamine dihydrochloride is used. 40988? / 136b - to - 21. The method according to claim I _5, characterized in that
an acid is used as the acidic catalyst. 22. The method according to claim 21, characterized in that the acid used is a Lewis acid. 23. The method according to claim 22, characterized in that boron trifluoride is used. 24. The method according to claim 21, characterized in that the acid used is a protic acid. 25. The method according to claim 24, characterized in that the protic acid is a mineral acid or an organic one Acid used. 26. Vei-driving according to claim 25, characterized in that the organic acid used is sulfonic acid or a carboxylic acid. 27. The method according to claim 24, characterized in that protic acid is hydrochloric acid, formic acid, Acetic acid, malonic acid, succinic acid, maleic acid, benzoic acid, cinnamic acid, benzenesulfonic acid or p-toluenesulfonic acid used-. 28. The method according to claim 1, characterized in that
in addition to the acidic catalyst, 0.01 to 0.5 Mo1-%
based on acetone used in process step a), a cocatalyst different from this is added. 409883 / 136b 29 .. The method according to claim 28, characterized in that as cocatalyst potassium iodide, sodium iodide, lithium bromide, Lithium iodide, lithium rhodanide, ammonium irhodanide, Lithium cyanide, lithium nitrate, ammonium sulfide, bromine, iodine or a bromide, iodide, nitrate, methanesulfonate, benzenesulfonate or p-toluenesulfonate of ammonia, triethylamine, Urea or thiourea added. 30. The method according to claim 1, characterized in that one in process step a) works at a temperature of 5 - 35 ° C, 31. The method according to claim 1, characterized in that the process step a) is carried out at a temperature of 5-25 ^° C. 32. The method according to claim 1, characterized in that the reaction in the presence of a mono- or polyfunctional Alcohol or mixtures of such alcohols. 33. The method according to claim 32, characterized in that one used a lower monoalcohol as alcohol. 34. The method according to claim 33, characterized in that methanol, ethanol, ethylene glycol monomethyl ether or Mixtures of these solvents are used. 35. The method according to claim 33, characterized in that the Aikoho1 used is Methano1. 36. The method according to claim 1, characterized in that at least 0.15 mol of ammonia is used per mol of acetone 409883/1365 242HH37 37. Ancestors geinass claim 32, characterized in that man a) Acetone in it: not less than 0.15 parts of ammonia per mole of acetone starting material in methanol or ethanol in the presence of 0.2 to 7 mol percent, based on acetone as the starting material, 1. an ammonium is a satire with a pK value below 5.0 or 2. the corresponding acid alone or 3. Boron trifluoride or 4. boron trifluoride is reacted in a mixture with the AmmoniumsaIz according to 1. or 2. in accordance with the acid at temperatures between 5 and 25 ^0C at least 3 hours and ansehliessend b) adding at least half of tind acetous used in process step a) allows the reaction to proceed at temperatures between 40 and 65 ⁰ C for at least 3 hours. 38. The method according to claim 37, characterized in that the catalyst used in process step a) is ammonite chloride or boron trifluoride or a mixture of both. 39. The method according to claim 38, characterized in that ._ that man a) saturates the acetone with ammonia gas and the reaction in methanol in the presence of 2-5 Mo1-%, relative to acetone, ammonium chloride at temperatures between 10 and 17 ⁰ C is reacted during 3 to 5 hours; b) the reaction continued at temperatures between 50 and 55 ⁰ C for 8 to 20 hours ;. 409883 / 13ßb 40. The method according to claim 1, characterized in that a Lewis or protic acid is used as the acidic catalyst in stage a) and it is carried out at 5-35 ° C., and in the Step b) the reaction by adding more acetone and / or diacetone alcohol, mesityl oxide, Phoron, diacetonamine or triacetonediamine completed by increasing the temperature. 41. The method according to claim 40, characterized in that in process step b) an additional amount of a Lewis acid or a protic acid is added. 42. The method according to claim 37, characterized in that in process step b) an additional amount of a Lewis acid or is added to a protic acid « 43. The method according to claim 42, characterized in that in method step b) boron trifluoride or ammonium chloride is added. 44. The method according to claim 42, characterized in that concentrated sulfuric acid is added in method step b) will. 45. Process according to claim 42, characterized in that hydrogen chloride is added in process step b). 46. The method according to claim 40, characterized in that in process step b) at least 0.5 part of acetone and / or diacetone alcohol or mesityl oxide is added per part of the acetone used in step a). 4098.83 / 136b 42 ": The method according to claim 46, characterized in that in process step b) 2-4 parts of acetone and / or diacetone alcohol or mesityl oxide per part of the in step a) added acetone used. 48. The method according to claim 37, characterized in that in process step b) 2-4 times the amount of the im Process step a) adds acetone used. 49. The method according to claim 37, characterized in that in step b) at least twice the amount of the acetone used in step a) and 0.05 to 1 mol calculated on the acetone used in step a) 97% sulfuric acid is added and the reaction between temperatures of 40 and 65 ⁰ C can take place for 8 to 20 hours. 50. The method according to claim 49, characterized in that hydrochloric acid is added instead of sulfuric acid in process step b). 51. The method according to claim 48, characterized in that one in process step b) the 2-4 times the amount of im Process step a) used acetone and 5-12 Mo1-%, based on the acetone used in step a) of concentrated sulfuric acid or of hydrogen chloride and the reaction is allowed to proceed for 8-20 hours at 40 to 65 ° C. 52. The method according to claim 2, characterized in that the acetone used is water and / or lower monoalcohols contains. 409883 / 136b 2423337 53. The method according to claim 1, characterized in that the reaction is carried out at above +5 ⁰ C and under pressure. CIBA-GEIGY AG FO 3.33 Sat / Tue / st 409883/1365