PL105245B1 - METHOD OF THE PRODUCTION OF CARBOXYLIC ACID BENZYL ESTERS - Google Patents

Description

The present invention relates to a method of producing esters benzylic carboxylic acids, which are half products for the synthesis of medicinal and fragrances and plasticizers.

Apart from the classical methods of obtaining acid esters carboxylic words, e.g. by the action of alcohol on acid chlorides is a known method of producing esters benzyl carboxylic acids by O-alkylation the sodium or potassium salt of the carboxylic acid at using benzyl chloride.

Reactions are carried out at elevated temperature, or in homogeneous phase using a solvent, e.g. a lower aliphatic alcohol such as ethanol, be in a two-phase environment with water. In both in these cases, mediocre yields are obtained product, which is unsatisfactory on a larger technical scale.

Production in a two-phase environment is known carboxylic acid methyl esters by reactions a water-soluble iodine salt of a carboxylic acid with methyl or dimethyl sulfate when used as a catalyst for a quaternary ammonium salt.

[AND. Brandström "Preparative lon Pair Extraction", A. B. Hassie, Móludal, Sweden 1974]. This method after allows to obtain methyl esters with satisfactory yield.

The object of the invention was to develop a manufacturing process of the benzyl esters of eliminic carboxylic acids the use of solvents and such burdensome reactions agents such as, for example, thionyl chloride, and for the preparation of washing the product on a larger technical scale with good with a yield exceeding 90% of the theoretical amount.

It has been found that this goal is achieved if known reaction between a water-soluble salt of an acid and one is fed alternately with benzyl chloride from an excess of the reactants, and an intermittent reaction is also obtained alternately be the organic layer if added in excess of acid salt, or in the case of water layer an excess of benzyl chloride was added and the product was evolved silver is removed from the organic layer in a known manner.

Moreover, it was found that there was an increase in productivity costs by 5-10% if in the process carried out according to of the invention, i.e. when the reactant is introduced alternately gents, catalytic amounts of salt or hydrogen are used ammonium oxide of the general formula R * R2R3R4N (+) X (-), wherein R1, R2, R3, R4 are the same or different and represent alkyl or benzyl groups with a total number of carbon atoms after the above 12, preferably 16-40, and X (-) is an anion halogen, sulfate or OH (-).

It has also been found that ammonium salts or hydroxides of the given formula used in catalytic amounts of prevent the reaction of benzyl chloride with the solution water-soluble salts of carboxylic acids not only when feeding one alternately with excess reagents, which is particularly convenient for continuous process, but also in a periodical manner physical.

These three possible variants of the method according to the invention for * they walk in an aquatic environment, at an elevated temperature round and the benzyl ester is isolated in a known manner from the organic layer, e.g. by distillation, extraction or concentration and crystallization. 105 2453 The ammonium salts or hydroxides used in the process are according to the invention, chlorides, sulfates or hydrogen oxides of such cations as tetrabutylammonium, tricap- rylmethylammonium, distearyl dimethylammonium, tributylbenzylammonium, tricaprylobenzylammonium.

Ammonium salts used as catalysts in the process according to the invention the invention may be introduced together with one of the reagents, or produced in the reaction environment by feeding the corresponding tertiary amine, which with chloride benzyl gives the ammonium salt. Such third-order amines can be, for example, tributyl amine, tricapryl amine or distearylmethyl.

Example 1 Up to 870 g of boiling 60% aqueous solution of the potassium salt of phenylacetic acid (3 moles in counted as dry salt) with a temperature of 110-115 °) contained Jacego 4 g of tricaprylmethylammonium chloride, dropwise with vigorous stirring for 1 hour. 254 g (2 moles) of benzyl chloride at the speed of laz worthy boiling of the mixture. After instillation of the entire portion The benzyl chloride mixture is boiled for a further 5-6 hours, then cooled to room temperature and a 40-50% KOH solution is added until reaching pH = 10 and the organic layer is separated, which distills under reduced pressure of about 10 mm Hg. A forerun is obtained with a boiling point of 60- —180 ° C in an amount of 45 g and ester fractions at temperature boiling 190-195 / 10 mm Hg in the amount of 382 g which is 85% yield with respect to benzyl chloride.

For a vigorously stirred water layer heated to bp (110-115 ° C), 254 g are added dropwise within 1 hour (2 moles) of benzyl chloride containing 2 g of tri caprylomethylammonium chloride (approx. 0.005 mol) and heated the mixture for 3 hours more, then added 100 g of water to dissolve the potassium chloride. After cooling After exposure to a temperature of about 80 ° C, the water layer is separated on. 580 g is added to the remaining organic layer 60% of an aqueous solution of the potassium salt of phenylacetic acid % (1.7 moles of dry salt) containing 2 g of tricaprylmethylammonium chloride and heated to boiling, stirring vigorously for 4-5 hours. Na¬ step-by-step after cooling to about 20 ° C, it becomes alkaline by 40- —50% KOH to pH 10, the organic layer is separated and distills as before. The water layer is thin with the same amount of benzyl chloride containing 2 g of the catalyst as given above and proceed as described above the cycle. The total yield of the ester converted to the phenylacetic acid consumed for the reaction is 95%. v Example II. To a boiling 50% aqueous solution sodium hydroxide (192 g, 2.4 mol NaOH) was added 292.8 g (2.4 moles) of benzoic acid and 1.85 g (0.01 mole) of tributylamine and during boiling, using vigorous stirring is instilled in 1/2 hour. 254 g (2 moles) of benzyl chloride.

Boiling of the reaction mixture is maintained for 7-8 hours After cooling, 16 g (0.2 mole NaOH) are added 50% aqueous sodium hydroxide solution, sat 100 g of water melts and the organic layer is separated subjected to distillation under reduced pressure.

356 g of benzyl benzoate are obtained, i.e. 166-168 ° / / 10 mm Hg. Yield in terms of benzyl chloride is 84%. From the water layer, 68 g (0.56 mole) of benzoic acid by concentrated acidification hydrochloric acid to pH 1. Benzyl benzoate yield based on the benzoic acid consumed, it is 92%.

LZG Z-d 3 in Pab., Zai 245 4 Example III. Up to 870 g of boiling 60% aqueous solution of the potassium salt of phenylacetic acid (3 moles in counting on dry salt) with a temperature of 110-115 ° is added dropwise with vigorous stirring for 1 hour 254 g (2 mole) of benzyl chloride fast enough gentle boiling of the mixture. After dripping all porqi the benzyl chloride mixture is boiled, for the next 5-6 hours, then it can be cooled room temperature and 40-50% solution is added.

KOH until reaching pH = 10 and the layer is separated organic which is distilled under reduced pressure German approx. 10 mm Hg. A forerunner of a temperature is obtained boiling point 60-180 ° in the amount of 48 g and ester fractions with a boiling point of 190-195 ° / 10 mm Hg in quantity 340 g, which is 75% of the yield in relation to the chloride benzyl. Then proceed as in the example I combined the yield of the ester is based on the used for the reaction phenylacetic acid 88%. As chloride benzyl yield is 84%. . twenty

Claims (4)

Patent claims 1. A method for the preparation of benzyl esters of carboxylic acids by treating a water-soluble salt of a carboxylic acid in aqueous solution with benzyl chloride, characterized in that an excess of one of the reactants is alternately fed and an alternating or alternating organic layer is also collected When an excess of an acid salt is added, or an aqueous layer when an excess of benzyl chloride is added, the product is isolated from the organic layer in a known manner. 2. A process for the preparation of benzyl esters of carboxylic acids * by treating a water-soluble salt of a carboxylic acid in an aqueous solution with benzyl chloride, characterized by the fact that it is fed; alternating one of the reactants in excess containing catalytic amounts of an ammonium salt or hydroxide of the formula R1R2R3R4N (+) X (~), where R1, R2, R3, R4 are the same or different and represent alkyl or benzyl groups with a total number of carbon atoms above 12 preferably 16-40, and X (-) is a halogen, sulphate or OH (-) anion, whereby either an alternate or an organic layer is obtained when an excess acid salt is added, or an aqueous layer when an excess of benzyl chloride is added and the product comes out of the organic layer in a known manner. 50 3. A process for the preparation of benzyl esters of carboxylic acids by treating a water-soluble salt of a carboxylic acid in aqueous solution with benzyl chloride, characterized in that catalytic amounts of the ammonium salt or hydroxide of formula 55 R ^ R ^ N (+) X (-), wherein R1, R2, R3, R4 are the same or different and represent alkyl or benzyl groups with a total number of carbon atoms of more than 12, preferably 16-40, and X (-) is a halogen, sulfate or OH anion (~). 60 4. The method according to p. The method according to claim 2 or 3, characterized in that the ammonium cations used are, in particular, tetrabutylammonium, tricaprylmethylammonium, distearylmethylammonium, tributylbenzylammonium, tricaprylobenzylammonium, n. 969-79, 100 + 20 copies 45 il \