CS201989B1 - Method of preparing alkyl-benzyl-dimethylammonium-bromides - Google Patents

Description

The invention relates to a process for the preparation of alkyl benzyldimethylammonium bromides of the formula I

CHο ₆ ^η 5 ° η ₂ -ν + R - Br

CHC.H, - CH ~ _O N ~ R 6 5 2 |

CH.

(I) wherein R is alkyl of 8 to 18 carbon atoms.

The compounds of the above formula are used as disinfectants. Carriers of significant antimicrobial activity are aliphatic chains of carbon atoms in the range indicated (Lawrence C.A. et al., J. Am. Pharm. Assoc, 36, 353, 1947). They are prepared by quaternizing the benzyldimethylamine of formula II, with the alkyl bromides of formula III, wherein R has the same meaning as in formula I, according to the equation

CHCH.

| 3

C ₆ H ₅ -CH ₂ -N-R

CH.

(i) (II) (III)

Podía čs. pat. file no. The compounds of formula I are prepared by reacting benzyldimethylamine with alkyl bromides in which the alkyl has 8 to 18 carbon atoms, without solvent, at a temperature of up to 100 ° C. The most frequently reported in the literature is the preparation of a compound of formula I wherein alkyl has carbon atoms, i.e. laurylbenzyldimethylammonium bromide of formula IV

CHCl 2 -Hc-CH 3 -NC-, _O H _{0 (} -Br> d)

CH, (IV), according to the above MS. pat. file and also according to French Pat. file no. 1,000,869 is prepared by reacting benzyldimethylamine with solvent-free lauryl bromide at a temperature of up to 100 ° C. The disadvantage of this procedure is that there are side reactions between the starting components and the product formed, which results in undesirable coloring and lower yields. Likewise, using ethanol and isopropanol as solvents produces similar products. According to Polish pat. file no. 62 185, the reaction of benzyldimethylamine with lauryl bromide is carried out in the presence of an amount of water such that 1.5-20% aqueous solutions of laurylbenzyldimethylammonium bromide are formed. A pure product is produced, but it is necessary to work with large volumes.

These disadvantages are eliminated by the procedure according to MS. aut. Certificate No. 157 7.12, wherein the quaternization of benzyldimethylamine with lauryl bromide is carried out with the addition of urea in the form of a 0.4 to 1% solution in water, the amount of which in the reaction mixture is 18 to 22% by weight. The disadvantage of this process is that the pure product and good product yield in the concentrated aqueous solution are achieved by a considerable long reaction time of 8 to 15 hours, which creates quite high energy and wage demands.

The disadvantages of the prior art are eliminated by the process for the preparation of the alkylbenzyldimethylammonium bromides of the formula I by quaternizing the benzyldimethylamine with the alkyl bromides of the formula III in a 1: 1 molar ratio according to the invention. C. The process according to the invention makes it possible to obtain the final product in satisfactory purity, good yield and in concentrated form in a short reaction time. The end product is an alkylbenzyldimethylammonium bromide itself, for example laurylhenzyldimethylammonium bromide or a mixture of alkylbenzyldimethylammonium bromides. According to the invention, laurylbenzyldimethylammonium bromide is prepared by quaternizing benzyldimethylamine with lauryl bromide in an aqueous solution of glycerol or monoethylene glycol at a temperature of 100 to 110 ° C. The procedure for the preparation of laurylbenzyldimethylammonium bromide can be used as a general procedure, e.g. a mixture of alkylbenzyldimethylammonium bromides having individual alkyls of 8 to 18 carbon atoms.

In an aqueous solution of glycerol or monoethylene glycol in the reaction temperature range of 100 to 110 ° C, the reaction progress between the starting materials is considerably accelerated. The advantage of using glycerol or monoethylene glycol is that these substances are commonly used as excipients in pharmaceutical products, so that their presence in the final product is not detrimental.

It can be seen from Examples 1, 2 and 3 that, under the conditions of the invention, the reaction time of the quaternization of benzyldimethylamine with lauryl bromide or alkyl bromides takes 2 to 4 hours. In addition, Example 3 shows that under the same conditions benzyldimethylamine is reacted with a mixture of alkyl bromides prepared from an appropriate mixture of alkanols in the range of C8 to C18. The prepared mixture alkylbenzyldimetylamóniumbromidov, particularly from a mixture of C ₂ and C ₄ and C ₁₃ and C ₁₅ are compared to the same order of magnitude laurylbenzyldimetylamóniumbromidom disinfection efficiency, as the normal j thermally stable against precipitation of the active ingredients in solid form and 1'ahšie applied as it remains for a long time in the liquid state. An advantage of the process for preparing the alkylbenzyldimethylammonium bromides according to the invention is that it allows the quaternization of benzyldimethylamine with alkyl bromides to be carried out in a short reaction time, reducing energy and wage costs and also allowing the preparation of a mixture of alkylbenzyldimethylammonium bromides. reduces the cost of (foreign exchange) funds needed to secure foreign raw materials.

Further details are given in the examples.

Example 1

A mixture of 200 g of lauryl bromide (99.9% by weight), 110 g of benzyldimethylamine (98.5% by weight) and a solution of 40 g of monoethylene glycol in 20 g of distilled water are heated and stirred for 2 hours at a reaction temperature of 110 ° C to pH 7.0. It is obtained

77.2% (w / w) solution of laurylbenzyldimethylammonium bromide.

Example 2

A mixture of 300 g of lauryl bromide (99.9% by weight), 165 g of benzyldimethylamine (98.5% by weight) and a solution of 35 g of glycerol in 55 g of distilled water are heated and stirred for 3 and a half hours in the reaction temperature to 108 ° C to pH 6.7. It is obtained

80.2% (w / w) solution of laurylbenzyldimethylammonium bromide.

Example 3

Into 600 g of a mixture of alkanol (octanol - -C 1.5 wt.% Cl _2-54% wt., C ₄₄ - 44% wt., And C _I8 - 1.5% wt.) Was added first, 25 g of red phosphorus, then 260 g of bromine is slowly admitted, reaching a temperature of 130 ° C. Bromine admission and cooling, respectively. heating of the reaction mixture is controlled to maintain the temperature for 4 hours. Stirring is then stopped, the reaction mixture is cooled to 50 ° C, the lower acidic layer (ca. 10 ml) is waste and the upper layer is mixed twice with approximately 300 ml of a solution prepared previously by dissolving 35 g of sodium carbonate and 25 g of sodium chloride in 550 g of water. 5 g of sodium pyrosulphite and 5 g of activated carbon are added to the crude alkyl bromide mixture with stirring and filtered after half an hour (or the crude alkyl bromide mixture is purified by a single vacuum distillation). 675 g of a mixture of alkyl bromides having an approximate composition of individual alkyls is obtained, such as the starting mixture of alkanols (bromine content 29.7% by weight), to which 350 g of benzyldimethylamine (99.6% by weight), 85 g of glycerol in 135 are added. g of distilled water and the mixture is heated and stirred for 4 hours in the reaction temperature range of 102 to 108 ° C to pH 6.5. A mixture of alkylbenzyldirhetylammonium bromides in a solution of 76% by weight is obtained. calculated on laurylbenzyldimethylammonium bromide.

Claims (1)

OBJECT OF THE INVENTION A process for the preparation of alkylbenzyldimethylammonium bromides of the formula I, cn ₃ En-H _C ~ CH _O ~ N - R 0 9 div wherein R is alkyl of 8 to 18 carbon atoms, quaternization of benzyldimethylamine with alkyl bromides of the formula R - Br, wherein R is as defined in formula I, in a 1 The composition of claim 1, wherein the quaternization is carried out in an aqueous solution of glycerol or monoethylene glycol at temperatures of 100 to 110 ° C.