DE2651984A1 - PROCESS FOR THE PRODUCTION OF N,N-DIMETHYLPIPERIDINIUM CHLORIDE RESPECTIVELY. N,N-DIMETHYLMORPHOLINIUM CHLORIDE - Google Patents

Description

BASF £ ktienecesellscaaft

Our reference: O.Z. 32 292 Sws / DK 6700 Ludwigshafen, 12.II.1976

Process for the production of NjN-dimethylpiperidinium chloride or NjN-dimethylmorpholinium chloride

The present invention relates to a process for the preparation of NjN-dimethylpiperidinium chloride or Ν, Ν-dimethylmorpholinium chloride from the corresponding monomethyl compounds and methyl chloride in the presence of water.

It is known Ν, Ν-dimethylpiperidinium chloride or N, N-dimethylmorpholinium chloride to use as a means for influencing the growth of plants (DT-PS 16 42 215 and DT-OS 22 07 575). she are applied in the form of an aqueous solution. They are produced in a known manner by converting N, N-dimethylpiperidinium iodide or Ν, Ν-dimethylmorpholinium iodide in the corresponding chlorides (HeIv. Chim. Acta 39, 399 (1956) or Chem. Ber. 22, 2091 (1889)).

It has now been found that Ν, Ν-dimethylpiperidinium chloride or Ν, Ν-dimethylmorpholinium chloride from N-methylpiperidine or N-methylmorpholine easily and in excellent yields if the monomethyl compounds with methyl chloride in the presence of water as a diluent a temperature of 0 to 100 ⁰ C and a pressure of 1 to 7 bar.

This is surprising and was not foreseeable because methylations were performed with methylene chloride previously either in non-aqueous solvents or when water was used as a diluent, were then temperatures (120 ⁰ C), which are far above the room temperature and high pressures (20 to 60 bar) is used.

The method according to the invention has two main advantages: First is through the use of water as a diluent

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the process is very simple and therefore very economical, since the aqueous solution of the end products is directly used for biological purposes can come. Second, the implementation at normal pressure or slightly increased pressure allows the use of inexpensive standard ones Stirred vessels, as these normally, even if they are intended for pressureless reactions, for safety reasons for a pressure from 4 to 7 bar.

The reaction can be carried out in the case of using N-methylpiperidine can be represented by the following formula:

<N-CH, + CH, C1> < N ^ Cl

σ * '

Compared to known methods, the inventive method provides Process in a simpler and more economical way the desired quaternary ammonium chlorides in good yield and high Purity. While the known methods were cumbersome because they had to be carried out in two stages, is according to the invention Procedure carried out the implementation in one step.

The starting materials for the process are N-methylpiperidine and N "-methylmorpholine and methyl chloride. They are used, for example, in approximately equivalent amounts, optionally with a slight excess of methyl chloride.

The implementation can be carried out, for example, as follows: Water and the monomethylamine are placed in the reaction vessel, the mixture is heated to the desired reaction temperature and then treated with methyl chloride. Become beneficial the reaction components are mixed with one another, for example by stirring. After the end of the reaction, the reaction solution is cooled to room temperature and then with water to the desired concentration of active ingredient diluted.

The concentration of the monomethyl amines in the water at the start of the reaction can be varied within wide limits. To be favoured

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those concentrations are used which are the concentrations after the reaction has ended of the end products which are slightly above the concentration of the aqueous solutions intended for sale. But you can also start with a more dilute aqueous solution and, after the reaction has ended, distill off some of the water used, without the quality of the end products suffering. The concentration of monomethylamines in the water is also allowed can easily be so high that they are not completely dissolved from the start or during the reaction.

Since methyl chloride is a gas, it is best to work in a closed apparatus. In the method according to the invention you can work without pressure or with pressure. The reaction is a little faster with pressure. If you work without overpressure, it is It is expedient to close the reaction vessel largely free of air by partial evacuation before the methyl chloride is introduced into the reaction vessel and then set the desired pressure by introducing methyl chloride into the container.

If you work at constant pressure during the implementation, then you can follow the course of the reaction on the amount of methyl chloride fed in.

The reaction is carried out at a temperature of O to IGO ⁰ C, preference * ', at least 20 ⁰ C, conveniently 30 to 80 ° C, in particular HO to 60 ⁰ C, batchwise or continuously.

The duration of the implementation is irrelevant for the quality of the end products. One can therefore adjust the response time according to the point of view set the greatest economic efficiency. For example, it may be cheaper to work without pressure because only a container for pressureless work is available · and a longer reaction time has to be accepted for this.

At the end of the reaction, no more methyl chloride is taken up and the reaction solution has a pH of 6-7. She poses then a clear, practically colorless liquid.

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The reaction according to the invention is practically complete the desired end products, i.e. there are no by-products, which means that the yield is practically quantitative.

The only by-products that can possibly occur originate from impurities in the starting materials. For example, if that N-methylpiperidine still contains small amounts of unsubstituted piperidine contains, the reaction with methyl chloride produces N-methylpiperidine hydrochloride, which is due to the formation of the hydrochloride is not further methylated. If one sets the starting solution basic substances that release the corresponding amines from amine hydrochlorides, e.g. sodium hydroxide, can be used Prevent the formation of the hydrochloride of the tertiary amine described above. If the emergence of the amine hydrochloride and If the metal chloride produced by the basic additive does not interfere, the process can be even more economical under certain circumstances. by starting with impure starting amines. If also a larger amount of metal chloride does not interfere, one can even from the beginning of the secondary amines, i.e. from piperidine or Mor-. pholine, go out and this under the reaction conditions described above in the presence of an equivalent of a basic additive react with methyl chloride. An aqueous solution of a mixture of one mole of quaternary is then obtained as the end product Ammonium chloride and one equivalent of metal chloride.

The method according to the invention is therefore also progressive, because it is very environmentally friendly. Solid or liquid waste does not arise at all, as the reaction solution directly does desired end product is. Gaseous emissions can largely be avoided by emptying the reaction vessel and charging the same with the raw materials without the preceding Ventilation of the container makes what can easily be done with the help of pumps.

Since the aqueous solution after the reaction has ended, some methyl chloride contains, this solution may be a source of emissions be considered of impurities. In this case you can

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lead the solution after completion of the reaction through an evaporator or a distillation column and thus the reaction solution from Free methyl chloride. The aqueous distillate thus obtained can then be used again as a diluent in the following production batch are fed.

Both Ν, Ν-dimethylpiperidinium chloride and Ν, Ν-dimethylmorpholinium chloride can be produced in the same apparatus, which may be of economic importance. at If necessary, both products can also be produced together in a mixture, which can be quite useful because the two products can also be used together with particular success in some plant crops.

If you want to isolate the two products as solid crystalline substances, you can do this easily by evaporating the corresponding aqueous solutions. They are obtained as colorless, coarse crystals of high purity with a melting point above 300 ^° C.

Embodiment

In a stirred vessel, which is provided with a heating jacket and has a volume of 100 parts by volume, 30 parts by volume Filled with water and 15.6 parts by weight of N-methylpiperidine (parts by volume relate to parts by weight as liters to kilograms). The apparatus was evacuated and heated to 50 °. At this Temperature were a maximum of 1000 parts by volume via a flow meter Methyl chloride fed in per hour and the mixture was stirred.

After about 2 hours, a pressure of 2 bar was reached and this was maintained by constant, controlled addition of methyl chloride Height held.

The heating mantle was charged during the reaction with water of 55 ° C, whereby the internal temperature at 49-50 ⁰ C was maintained.

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After 7.25 hours, the pressure remained constant without further addition of methyl chloride. The mixture was stirred for a further 0.75 hours and then emptied the apparatus so that the bottom valve was just covered and so that the container was not depressurized.

The solution thus obtained was a yellowish clear liquid, showed a pH of 6.9 and, according to a content determination, contained the Ν, Ν-dimethylpiperidinium chloride as a tetraphenylborate complex precipitated and determined gravimetrically, 0.46 parts by weight per 1 part by volume. The yield was thus quantitative.

The consumption of methyl chloride corresponded to a molar ratio of N-methylpiperidine to methyl chloride of 1: 1.02.

Completely analogously, one obtains from N-methylmorpholine and methyl chloride Ν, Ν-dimethylmorpholinium chloride, the reaction time being 14 hours amounts to.

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Claims (1)

- r- OZ 32 292 Process for the preparation of N ^ N-dimethylpiperidinium chloride or Ν, Ν-dimethylmorpholinium chloride by reacting N-methylpiperidine or N-methylmorpholine with methylating agents, characterized in that the monomethyl compounds are mixed with methyl chloride in the presence of water as the diluent at a temperature of 0 to 100 C and a pressure of 1 to 7 bar. BASF Aktiengesellschaft 809820/0384