JP2539876B2 - Method for producing 2,2,6,6-tetramethyl-4-oxopiperidine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for the synthesis of 2,2,6,6-tetramethyl-4-oxopiperidine. The present invention relates to a method for directly producing 2,2,6,6-tetramethyl-4-oxopiperidine from acetone and ammonia at low temperature and low pressure.
More specifically, the present invention relates to reacting acetone with ammonia in the presence of a novel catalyst. Such catalysts include sulfonyl halides, haloamides, haloimides, β
-Comprising active halogen-containing compounds selected from haloesters, β-halonitriles, α-halohydroxy compounds, β-haloketones and alkyl and aryl derivatives of sulfuryl halides.

A conventional synthetic method for the preparation of 2,2,6,6-tetramethyl-4-oxopiperidine (ie triacetoneamine) is the reaction of excess acetone with ammonia at low temperature in the presence of a Lewis acid. , Making acetonin as an intermediate and then hydrolyzing it at higher temperatures. Acetonin is formed in the first step at room temperature and is converted to triacetoneamine at 50-70 ° C. Triacetoneamine is isolated by distillation in a yield of up to 85% or by precipitation with water in the form of the hydrate in a yield of up to 73%.

We have discovered that a group of active halogen compounds can be used in place of the prior art catalysts to improve the reaction rate and also improve the yield at lower temperatures and pressures.
The process according to the invention comprises two stages which can be carried out immediately and continuously in the same reactor, so that the process is particularly suitable for large-scale commercial production of the tetramethylpiperidine product.

The process according to the invention is carried out as follows: Acetone at (a) 0.5 to 30 ° C. per mol of acetone used.
In the presence of "active halogen compound catalyst" 01 to 0.1 moles of ammonia at a concentration of acetone per mole 0.5 to 1.5 moles of NH _3: then (b) by further heating to 50-70 ° C., NH ₃ React with additional acetone at a concentration of 5 to 10 mol acetone per mol:

As the catalyst, sulfonyl halide R-SO ₂ X, sulfuryl halide SO ₂ X _2, N-haloimides RCO-N (X) -CO
R, N-haloamide RCO (NHX), β-haloester RCH
_{(X) CH 2 -CO 2 R} , β- halonitrile RCH (X) CH ₂ -C
There are N, α-haloalcohols RCH (OH) -CH ₂ X and α-haloketones RCOCH ₂ (X), where X is chlorine or bromine and R is an alkyl having up to 22 carbon atoms, an alkyl It is a hydrocarbon group selected from alkyl and alkylaryl groups. Examples of such compounds include tetrachloro-1,4-benzoquinone, methanesulfonyl chloride, sulfuryl chloride, 1,3-dibromo-5,5.
-Dimethylhytanthione, 1,3-dichloro-5,5-dimethylhytanthione, N-bromosuccinimide, trichloromelamine, trichloroisocyanuric acid, 3-chloropropionitrile, ethyl-3-chloropropionate,
There are 1,3-dichloro-2-propanol and N-chlorosuccinimide, and their chloro or bromo equivalents.

The first stage of the reaction can be carried out at a temperature of about 25-30 ° C. at atmospheric pressure. The second stage can then be carried out at a temperature of 50-70 ° C with the addition of acetone.

The practice of the method of the present invention may be better understood with reference to the following non-limiting examples. In the example,
All amounts and proportions are by weight unless otherwise indicated.

Example 1 74 g (0.0375 mol) of 1,3-dichloro-5,5-dimethylhydanthione and 135 g of acetone were charged into a bottle equipped with a rubber liner, a steel cap and a magnetic stirrer. There was a small hole in the crown into which a needle for evacuation or liquid injection was inserted. The water aspirator vacuum was applied for a few minutes and the pins were weighed. After depressurization, 21 g of ammonia was introduced at 21 ° C. for 1 hour. After 2 hours at room temperature, 300g of acetone was added and the temperature was kept at 67 ° C for 4 hours.
And allow the reaction to continue overnight at 56 ° C. According to gas chromatographic analysis, the reaction solution contained 138 g of 2,2,6,6-
It contained tetramethyl-4-oxopiperidine (hydrate). Add 20 g of sodium hydroxide to this solution and
Stirred for hours. The two phases were separated and 270 g of acetone and low boiling by-products were recovered by fractional distillation under the pressure of 15 mmHg in the temperature range of 30 ~ 84 ℃, acetone, mesityl oxide, diacetone alcohol, acetonin and a few g Was obtained. Another fraction cut (84 mm at 15 mmHg
Upon boiling at 88 ° C), the product was recovered in a yield of 84.2% (based on acetone used).

Example 2 By the operation and apparatus described in Example 1, 10.7 g (0.037
5 mol) of 1,3-dibromo-5,5-dimethylhydanthione and 135 g of acetone were charged to a bottle. 20.5 g of ammonia was added over 3 hours. After adding 300 g of acetone, the reaction mixture was kept at 67 ° C. for 8 hours. The yield determined by gas chromatography was 78.1% (based on acetone used).

Example 3 By the procedure described in Example 1, 4.3 g (0.0375 mol) of methanesulfonyl chloride and 135 g of acetone and 21 g of ammonia were added to the reactor. The reaction was continued at room temperature for 1.5 hours. After adding an additional 300 g of acetone, the reaction was performed at 56 ° C.
It lasted for 16 hours. The yield determined by gas chromatography was 81.5% (based on acetone used).

Example 4 According to the procedure of Example 1, 4.3 g (0.0375 mol) of methanesulfonyl chloride and 435 g (7.5 mol) of acetone and 21 g of ammonia are introduced into the reactor and placed in a water bath at 69 ° C. Maintained for hours. By the same recovery operation as in Example 1, 80.8% (based on acetone used) was achieved.

Example 5 The procedure of Example 1 was used to achieve a yield of 83.5% (based on acetone used) using 13.3 g (0.075 mol) N-bromosuccinimide.

Example 6 The procedure of Example 1 was used to achieve a yield of 81.8% (based on acetone used) using 10.2 g (0.075 mol) of ethyl-3-chloropropionate and 21 g of ammonia.

Example 7 In the procedure of Example 1, 7.0 g (0.075 mol) of 3-
A yield of 79.7% (based on acetone used) was achieved using chloropropionitrile and 22 g of ammonia.

Example 8 According to the procedure of Example 1, using 3 g (0.045 mol) of sulfuryl chloride and 21 g of ammonia, 84.4%
Yield (based on the acetone used) was achieved.

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor John F. Stephen William Penn Boulevard, West Chester, 19380, Pennsylvania, United States 200 (56) References JP-A-62-45574 (JP, A) JP-A-62-129267 (JP, A) JP-B-59-29589 (JP, B2) Japan Chemical Journal, Vol. 90, No. 3 (1969), pp. 296-299

Claims (3)

(57) [Claims] 1. A method for producing 2,2,6,6-tetramethyl-4-oxopiperidine, which comprises reacting acetone and ammonia at a temperature in the range of 5 to 70 ° C., wherein SO ₂ X
_{2, R-SO 2 X,} RCO-N (X) -COR, RCO (NHX), RCH
_{(X) CH 2 -CO 2 R} , RCH (X) CH 2 -CN, RC (OH) -CH 2 X
And RCO—CH ₂ (X) where X is chlorine or bromine and R is a hydrocarbon group selected from alkyl, aryl, arylalkyl and alkylaryl groups having up to 22 carbon atoms. ] The above reaction is carried out in the presence of a catalytic amount of an active halogen compound selected from the group consisting of 2,2,6,6-tetramethyl-4-
Process for producing oxopiperidine. 2. Acetone is used in an amount of 0.5 to 1.0 per mol of acetone.
By heating with ammonia at a molar NH ₃ concentration in the range of 5-30 ° C., followed by additional acetone and further 50-70 ° C. at a concentration of 5-10 mol of acetone per mol NH ₄ ; The method according to claim 1, wherein the reaction is carried out. 3. An active halogen compound is tetrachloro-1,
4-benzoquinone, methanesulfonyl chloride, sulfuryl chloride, 1,3-dibromo-5,5-dimethylhydanthione, 1,3-dichloro-5,5-dimethylhydanthione, N-bromosuccinimide, trichloromelamine,
Trichloroisocyanuric acid, 3-chloropropionitrile, ethyl-3-chloropropionate, 1,3-dichloro-2-propanol and N-chlorosuccinimide,
And the method of claim 1 which is selected from the group consisting of these chloro or bromo equivalents.