SU695553A3 - Method of preparing m-phenoxybenzaldehyde - Google Patents

Description

The prepared brominated product (627 g) has the following composition,%: 3-phenoxytoluene (unconverted) 2.1; 3-phenocibenzyl bromide 61.5; 3-phenoxybenzalbromide 36,4.5

B. Preparation of g-phenoxybenzaldehyde.

The brominated mixture is added to 1 liter of glacial acetic acid and 360 g of hexamethylenetetramine (2.5 mol), and then to 1 liter of water. After incubation for 4 hours under reflux (105 ° C), 500 ml of concentrated hydrochloric acid is added, and after 5 minutes, 700 ml of water | And the mixture is heated for 15 minutes with a vertical condenser.

After cooling to room temperature by immersion in ice water, the reaction mixture was extracted with methylene dichloride (3x500 ml). The combined extracts are washed with a neutral solution (pH 7-20 8) with a saturated solution of sodium bicarbonate, and then washed again with 1 l of water with H0% glacial hydrochloric acid, and then with 1 l of water. After drying with anhydrous sodium sulfate, methylenedi- 25 chloride is removed and the remaining product is degassed to constant weight under high vacuum (0.1 mm Hg) to obtain 430.5 g (2.172 mol) of 3-phenoxybenzaldeg: ida. The yield of the target product is 93%, based on the initial 30% 3-phenoxytoluene with a purity of 99.5%.

Example 2. Getting l-phenoxybenzaldehyde from the corresponding bromides of benzyl and benzal.

Brominated L1 - phenoxytoluene 35 (33.65 g), obtained in Example 1 (A), is added to a solution of hexamethylenetetramine (16.8 g) dissolved in chloroform (140 ml). The mixture is stirred overnight and then salt 40 is filtered off (41.5 g), which is dissolved in acetic acid (35 ml) and water (35 ml) and heated with cooling for 4 hours. After adding concentrated hydrochloric acid (27 ml), cooling is continued for 45 hours and a further 0.5 hours. The cooled reaction mixture is extracted with methylene chloride (30 x 20 ml), the organic extract is washed with a neutral aqueous solution of sodium bicarbonate, then the solvent is evaporated, and 50 the residue is distilled, obtaining g-phenoxybenzaldehyde (14.6 g, 61%) as a colorless liquid, i.e. 140-141 ° C / 1 mm Hg Art.

Example 3. Getting. M-phenoxybenzaldehyde from the corresponding chlorides 55 benzyl and benzal.

A mixture of 3-phenoxybenzyl chloride and 3-phenoxybenzalchloride (50 g), containing 60% monochloride and 40% dichloride, is added to a solution of hexamethylentetra-60 mine (35 g) in acetic acid (100 ml) and water (100 ml) and a mixture of the mixture is heated with cooling for 4 hours. Then hydrochloric acid is added and the mixture is cooled for 15 minutes.65

After cooling to room temperature, the reaction mixture was extracted with methylene chloride (3 x 50 ml). The combined extracts are washed with a neutral aqueous solution of sodium bicarbonate, dried with anhydrous sodium sulfate and evaporated to obtain 3-phenoxyben-3 aldehyde (41.9, yield 97%),

Example 4. Preparation of ./-phenoxybenzaldehyde from the corresponding benzyl and benzal bromides.

The formalin solution (40%, 50 ml) is cooled to 10 ° C and then treated with an aqueous solution of ammonia (35%, 25 ml) for 15 minutes. The crude bromide mixture (25 g) obtained in Example 1A is added and the mixture is stirred under a layer of nitrogen for 4 hours. The mixture is then oxidized with acetic acid (50 ml) and heated with draining for 3 hours. After cooling, the reaction mixture extracted with toluene (25 ml) and the extract washed with a neutral sodium bicarbonate solution. The toluene solution of the crude 3-phenoxybenzaldehyde is diluted with an equal amount of ethanol and then stirred with a saturated aqueous solution of sodium bisulfite. The bisulfite composition formed is filtered off and washed with toluene until no colored impurities are present. After vacuum draining, 20.5 g of purified 3-phenoxybenzaldehyde bisulphite composition is obtained, which, after treatment with inorganic acid, is converted to pure 3-phenoxybenzaldehyde. The yield calculated from the chloride mixture, 77%.

Example 5. Preparation of i-phenoxybenzaldehyde from the corresponding benzyl and benzalchlorides.

The formalin solution (40% 150 ml) is cooled to 10 ° C and treated with an aqueous solution of ammonia (35% 75 ml) for 15 minutes. A mixture of 3-phenoxybenz1-chloride and 3-phenoxybenzalchloride containing 70% monochloride and 30% dichloride (50 g) is added and shifted under nitrogen for 3 hours. The mixture is then oxidized with acetic acid (150 ml) and stirred for 3 hours for cold After cooling, the reaction mixture was extracted with toluene (100 ml) and the extract was washed with a neutral solution of sodium bicarbonate. The resulting bisulfite product is filtered and washed with toluene. After vacuum drying, 63.0 g of purified 3-phenoxybenzaldehyde bisulfite is obtained, which, after treatment with an inorganic acid, is converted to pure 3-phenoxybenzaldehyde. The yield calculated by the mixture of chlorides, 95%.

Claims (2)

Claims 1. Method of preparation -fe6 Noxitoluenes use a mixture of W-phenoxybenzyl and L-phenoxybenzal halides and hydrolysis is carried out at a pH of from 3 to 6.5. 2. A method according to claim 1, characterized in that the intermediate is hydrolyzed in the presence of acetic or inorganic acid.