PL102521B1 - METHOD OF MAKING META-PHENOXYBENZALDEHYDE - Google Patents

Description

The subject of the invention is a method for the production of -phenoxybenzaldehyde, a valuable intermediate for the production of throwing insecticides known as pyrethroids.

There is known a method of producing benzaldehyde involving on the hydrolysis of the benzylidine halide (dihalide). 5 However, this method on an industrial scale has the disadvantage that it is difficult to obtain a sufficiently output dihalide cleanliness. Direct halogenation of toluene always leads to the formation of a halogenated mixture products where the halide is usually predominant 10 benzyl (monohalide).

The second known method for producing benzaldehyde is on the Sommelet's reaction, first proposed in 1913. In this reaction, the benzyl halide reacts with hexamethylene tetramine with the production of compound 15 complex which, upon hydrolysis, gives benzaldehyde hyd. However, this method is also very disadvantageous due to the difficulty of obtaining pure benzyl halide.

Separation of benzyl halide from large amounts of halide benzylidene, formed during direct chlorine- 20 toluene production is a difficult and costly task.

Takwiec for over 60 years, since the detection of the Sommelet's reaction, due to the difficulty of obtaining the starting materials of the required purity, there was no satisfactory method industrial-scale production of metaphenoxybenzal- 25 dehyde.

It has now surprisingly been found that if the meta -phenoxytoluene undergo direct halogenation, '^ v and then a mixture of meta-pheno halide prepared xybenzyl and meta-enoxybenzylidene halide (i.e. 30 mixture of one halide and dihalide) Sommelet reaction, the halide contained in this mixture meta-phenoxybenzylidene did not interfere with formation complex with hexamethylene tetramine and hydrolysis, to which this mixture is then subjected, leads to transformations of both the complex and the single compound halide in meta-phenoxybenzaldehyde obtained from the process high performance.

According to the invention, the method of producing meta-phenoxy of the benzaldehyde of the formula I is prepared a mixture of meta-phenoxybenzyl halide of formula 2 and meta-phenoxybenzylidene halide of formula 3, where in these formulas, Hal represents a halogen atom, th halogenation of meta-phenoxytoluene of Formula 4 with using halogen gas at elevated temperatures and in the presence of a free radical initiator, then the mixture thus obtained is reacted with ammonia and formaldehyde or with hexomethylene tetramine, po whereby the resulting intermediate is hydrolyzed in the shaft acid conditions at a pH in the range of 3-6.5 to give meta-phenoxybenzaldehyde.

In the second step of the process, instead of ammonia and formaldehyde hydu with a similar effect is used hexamethylene tetraamine that exists in chemical equilibrium with ammonia and formaldehyde. Longline ammonia and formal dehydrate can be treated as a hexomethylene precursor tetramines and vice versa - the latter as a source of ammonia and formaldehyde.

Reakqe with ammonia and formaldehyde, or with six methyltetraamine, can be run in a water- 102 521 102 521 3 non-aqueous or non-aqueous, e.g. in chloroform, but due to for the next step involving hydrolysis, it is preferably used aquatic environments. So you can use ammonia, formaline and hexamethylene tetraamine in the form of a solution water formations. The reaction in this step is exo thermally and its initiation does not require heating.

In practice, the reactions are preferably carried out at a temperature of temperature in the range of 10 ° * C - 150 ° C. Manufactured product the intermediate is a mixture of a halide complex salt benzyl and substantially unreacted halide benzylidene. These compounds before being subjected to hydrolysis can be separated from the reaction mixture, it is not necessary, as it was found that the hydrolysis of this mixture was found And it runs glaflfca and ^ efficiently.

The hydrolysis is generally carried out in the pH range from 3 to 6.5, preferably at a pH of 5-6. For adjusting the pH, medium The viscosity can be one hundred organic or inorganic acid. * as a favorable example of acids one can mention the acid acetic, phosphoric, salt or sulfuric, especially 50% wt. acetic acid. Hydrolysis can be taken after heating wajac acidified mixture of reaction jjfij ^^ from cooler feedback or in any other suitable known manner. Tempera the round of hydrolysis is generally in the range from 80 ° C to 200 ° C, preferably from 80 ° C to 120 ° C.

It has been found that the second step of the method according to the invention can run in the presence of the acid that is being used in the hydrolysis step, getting an even better yield.

For example, the second step can be done by adding benzyl and benzylidene halides to a hexagonal solution methylene tetramine in acetic acid and heating mixture under reflux condenser. You can hydrolyze also carry out in the presence of mineral acid, for example hydrochloric acid which is added in the second step or in the third process step or at the end of the hydrolysis, if necessary.

A major advantage of the process according to the invention is that the possibility of using a mixture containing a halide benzyl and benzylidene halide at any rate sunku.

The high yields of aldehyde in the process according to exc the invention has been achieved using mixtures of bromides and chlorides benzyl and benzylidene.

A mixture of benzyl and benzylidene halides can be prepared in any known way. Found however, such a mixture is conveniently obtained by reaction halogenation of the corresponding toluene. So I got out the raw material of the method according to the invention, i.e. a mixture meta-phenoxybenzyl halide and meta- -phenoxybenzylidene, can be prepared by halogen meta-phenoxytoluene halogen gas, in the following higher temperature and in the presence of a free initiator radicals. The temperature of the halogenation reaction depends largely on the chemical properties of the used halogen and whether it is necessary to avoid it halogenation of the toluene ring. Halogen reaction- It essentially takes place in the temperature range from 50 ° C to 250 ° C.

It has been found that with bromination, better results is obtained by the action of gaseous bromine on meta-phenoxy- toluene at a temperature of 180-250 ° C, preferably at ultraviolet irradiation, which acts as an initiation the free radical track. In order to get the maximum the yield of benzyl bromide and benzylidene bromide an excess of gaseous bromine is preferably used. 4 There may be an excess of bromine over the toluene used sic e.g. from 10% to 25% and even up to 30% by mole. Gdjr bromine is used in excess, petrol bromide content Lidene in the mixture produced is greater than. when using bromine in stoichiometric amounts ^ or in a slight molar deficiency. However, because: in the method according to the invention transformed into a response Both mono- and dibromide undergoes greater than the aldehyde the dibromide content in the resulting mixture bromination is not a problem. By doing so, you can to obtain benzyl and benzylidene bromide in yield over 90%.

However, in the case of chlorination of meta-phenoxytoluene it has been found that better results are obtained by gas treatment chlorine to meta-phenoxytoluene dissolved in non-polar solvent, at a temperature in the range of 40-100 ° C and in the presence of a free radical initiator which is used there must be a peroxide, e.g. benzoyl peroxide (NB), or an azo compound, e.g. azoisobutyronitrile (AIBN).

Such a solvent must be selected for the chlorination reaction non-polar, which does not favor ring chlorination and does not substantially affect the chlorination conditions. Respond are halogenated with suitable solvents for this reaction hydrocarbons, e.g. carbon tetrachloride and chlorobenzene.

Very good results have been obtained with the use of tetrachloride coal.

It has also been found that the conditions for chlorination are favorable toluene side chain at the expense of breast chlorination shade is achieved when the concentration of toluene in the dissolved % in the total amount of the solvent does not exceed a certain value, e.g.

* Toluene concentration found to be favorable in. generally in the range from 5 to 50 wt.%.

The conversion of toluene should not be completed, because then unwanted by-products are formed chlorination. Chlorination should be stopped when when the conversion of the meta-phenoxytoluene is 95-99%, preferably 98-99%. As in the case of in the case of bromination, the yield of mono- and dichloride is. usually above 90% and often even above 95%.

The invention is illustrated by the following examples: Example I. a). Formation of meta-phen bromide xybenzyl and benzylidene. 430 g (2.337 moles> Of 3-phenoxytoluene placed in a 5-liter reactor filled with With nitrogen, the amount of bromine was applied 473 g (2.956 mol). There was a source in the reactor ultraviolet rays, the vicinity of which he found bromine stream outlet. Reactor content vigorously: mixed. Molar excess of bromine in relation to phenoxy- 50 of toluene was 26.5%. After about 3 hours it was finished the bromine feed was left to stand for the reaction mixture night to cool down. While cooling through the mixture a stream of nitrogen was passed. 627 g of product was obtained bromination with the following composition: 55 meta-phenoxytoluene (unreacted) 2.1% meta-phenoxybenzyl bromide 61.5% meta-phenoxybenzylidene bromide 36.4% b) Preparation of meta-phenoxybenzaldehyde. Up to 1 liter glacial acetic acid and 350 g (2.5 moles) of six 60 methylene tetraamine was added from the mixture obtained in (a) * and then 1 liter of water. The mixture was heated for 4 hours for a reflux cooler at 105 ° C, then 500 ml of concentrated hydrochloric acid was added and elapsed minutes 700 ml of water. The mixture was further heated under 65 and reflux for 15 minutes and cooled to tempera-102,521 50 ml. The combined extracts were neutralized by washing aqueous sodium bicarbonate solution, dried over anhydrous sodium sulfate and obtained after evaporation 41.9 g of meta-phenoxybenzaldehyde with a yield of 97%.

Example IV. Preparation of meta-phenoxybenzaldehyde hydu from the corresponding benzyl and benzylide bromides new. Up to 50 ml of a cooled to 10 ° C 40% solution formalin was added over 15 minutes to 25 ml of 35% aqueous ammonia solution. Then 25 g of crude mixture was added shreds of bromides, produced as in example Ia, and the whole stirred under nitrogen for 4 hours. Mixture it is acidified with 50 ml of acetic acid and heated under chilled reflux for 3 hours and, after cooling, extracted ml of toluene. The toluene extract was neutralized by washed with sodium bicarbonate solution, diluted equal to ethanol and partitioned between saturated aqueous sodium bisulfite solution. Received relationship bisulfite was filtered off and washed with toluene az to the disappearance of colored impurities. Drying out 20.5 g of purified bisulfite compound were obtained of a new 3-phenoxybenzaldehyde, the action of which of thin mineral acid, pure meta -phenoxybenzaldehyde. Yield, calculated from the mixture chloride was 77%.

Examples V - VII. Prepare a mixture meta-phenoxybenzyl chloride and meta-phenoxy- benzylidene. For heated under the radiator, reversible at 80 ° C of a solution of 10 g of meta-phenoxytoluene and 0.25 g free radical initiator in 100 ml of carbon tetrachloride a chlorine stream was introduced as solvent. Out A series of experiments were done with different reaction times and various initiating factors. The results of these experiments are given in the table below.

The above list shows that selectivity, i.e. total wt.% mono- and dichloride, depending on the presence free radical initiator and the degree of reaction tohienia (cf. example VI, in which leading relatively low selectivity was achieved until the end of the reaction).

In another series of experiments, the effect of concentration was shown toluene in a solvent on selectivity: found that selectivity decreases with increasing toluene concentration.

Example VIII. Preparation of meta-phenoxybenzal dehyde from the corresponding benzyl and benzylide chlorides new. Up to 150 ml of a cooled to 10 ° C 40% solution ) Blackboard Example V *) V>) VII attempt counter

Initiator free radicals AIBN AIBN NB Time reaction (h) 0.75 1.00 1.50 3.00 1.00 1.00 3.00 7.00 % conversion important toluene 77 93 99 100 98 14 27 47 Product composition (wt%) chloride 1 84.5 74.5 54.9 2.7. 67.3 61.0 65.0 64.0 two Tuesday 14.9 ' 24.2 42.0 66.3 32.1 11.0 8.5 9.4 contaminated cleaning **) 0.6 3.1 , 9 0.6 28.0 26.5 26.6 Selective nosc (%) 99.4 98.7 • 96.9 | 69.0 | 99.4 | 72.0 73.5 73.4 | *) with nitrogen passing *) chlorinated products in the ring: AIBN - azoisobutyronitrile NB - "- benzoyl peroxide room by immersion in ice water. Then the non-reaction mixture was extracted with dichloride methylene in the amount of 3 times 500 ml. Combined extracts neutralized (pH 7-8) by washing with saturated sodium bicarbonate, washed once with 1 liter of 10% 5 hydrochloric acid solution in ice water and once 1 liter of water. After drying the extracts over anhydrous methylene dichloride was distilled off with sodium sulfate and residue degassed under high vacuum (0.1 mm Hg) to constant weight, yielding 430.5 g (2.172 moles) of meta-pheno xybenzaldehyde.

NMR showed 95% product purity and chro * gas-liquid matography showed that all the bromide benzyl and benzylidene bromide have undergone waving. Yield of meta-phenoxybenzaldehyde (2.172 mol) 15 based on the starting amount (2,337 mol) of meta-phenol xytoluene was 93%.

Example II. Preparation of meta-phenoxybenzaldehyde high from the corresponding benzyl and benzylidene bromides wego. The brominated m-pheno obtained in Example 1a xytoluene (33.65 g) was added to the solution of 16.8 g of hexamethyl lenbtetramine in 140 ml of chloroform and stirred for night. After filtering, 41.5 g of salt was obtained which was dissolved it was taken up in 35 ml of acetic acid and 35 ml of water. Solution heated under reflux for 4 hours, then 25 27 ml of concentrated hydrochloric acid were added and heated under a reflux cooler for the next 0.5 hours. Chilly the reaction mixture was extracted with methylene chloride 3 times 20 ml each and the organic layer was neutralized by washing with an aqueous solution of bicarbonate 30 sodium. After evaporation of the solvent, the residue was left to evaporate distilled to obtain 14.6 g (61%) of m-phenoxybenzal- dehyde in the form of a colorless liquid at boiling point 140 - - 141 ° C / 1 mm Hg.

Example III. Preparation of meta-phenoxybenzaldehyde 35 hydrocarbon from the corresponding benzyl and benzylidene chlorides wego. For a solution of 35 g of hexomethylene tetramine in 100 ml of acetic acid, 50 g of a chloride mixture were added meta-phenoxybenzyl chloride and metafenoxybenzylide chloride new, containing 60% monochloride and 40% dichloride. 40 Then 100 ml of water was added and the mixture was heated under reflux for 4 hours, then added concentrated hydrochloric acid and heated further for 15 minutes.

The reaction mixture was cooled to room temperature The mixture was extracted with methylene chloride 3 times 45102 521 each 8 formalin was added in 15 minutes to 75 ml of 35% aqueous ammonia solution. 50 g of the mixture was then added meta-phenoxybenzyl chloride and meta-phenoxy- benzylidene, containing 70% monchloride and 30% of dichloride and was stirred all over under a nitrogen atmosphere for Three hours. The mixture was acidified with 150 ml of acetic acid and stirred without heating for 3 hours under a cooler reflux for 4 hours. After cooling the reaction mixture extracted with 100 ml of toluene and the extract was neutralized with washing with sodium bicarbonate solution. Solution the crude m-phenoxybenzyldehyde in toluene was diluted equal amount of ethanol and mixed with a saturated solution aqueous sodium bisulfite. The obtained water adduct sulfite was filtered off and washed with toluene. After drying in the vacuum, 63.0 g of a purified water compound of the sulfite m-phenoxybenzaldehyde from which it acts A pour of dilute mineral acid was isolated pure m-phenoxybenzaldehyde. Yield, calculated with the property chloride equilibrium was 95%.

Claims (3)

Patent claims A method for the preparation of meta-phenoxybenzaldehyde of the formula I, characterized by the preparation of a mixture of metaphenoxybenzyl halide of the formula II and meta-phenoxybenzylide halide of the formula III, where in the formulas Hal is a halogen atom by halogenation of - phonoxytoluene of the formula 4 using halogen gas at an elevated temperature and in the presence of a free radical initiator, then the mixture thus prepared is reacted with ammonia and forrialdehyde or with hexamethylene tetraamine, whereupon the intermediate product thus formed is hydrolyzed under acidic conditions at pH 10 in the range 3-6.5 to give methylphenoxybenzaldehyde. 2. The method according to claim The process of claim 1, wherein the mixture of meta-phenoxybenzyl halides and meta-phenoxybenzylidene is prepared by reacting meta-phenoxytoluene with gaseous bromine used in an excess of 10-30 mol%, at a temperature in the range of 180-250 ° C and in the presence of ultraviolet light as an initiator. 3. The method according to p. 1. characterized in that the mixture meta-phenoxybenzyl halides and meta-phenoxybenzylidene are prepared by reacting meta-phenoxytoluene in a nonpolar solvent at a temperature in the range of 40-100 ° C with chlorine gas and in the presence of a CHC 9% peroxide or azo initiator. W WZ0R 1 Hal.CH -Q 9 W 2 \ = j WZ0R 2 (Hal) 2CH-pQ CH. , -d »-o MODEL 3 WZ0R U LZG Z ^ d 3 order 217-79 Raalkl. 95 + 20 copies Price PLN 45