Preparation method of 4-n-heptylbenzoyl chloride_Kain Industrial Additive

Background and overview^[1]

4-n-Heptylbenzoyl chloride can be used as a pharmaceutical synthesis intermediate. If 4-n-heptylbenzoyl chloride is inhaled, move the patient to fresh air; if the skin comes into contact, take off contaminated clothing, rinse the skin thoroughly with soap and water, and seek medical treatment if you feel uncomfortable; if the eyes are clear In case of contact, separate eyelids, rinse with running water or saline, and seek medical attention immediately; if ingested, rinse mouth immediately, do not induce vomiting, and seek medical attention immediately.

Preparation method^[1]

The preparation of 4-n-heptylbenzoyl chloride is as follows:

(m=8)

1) Add 80 mL thionyl chloride (1.2 mol) into a 250 mL three-necked flask, heat to 50-60°C, add 70.9 mL heptanoic acid (0.5 mol) dropwise within 1 hour, and heat to reflux until no hydrogen chloride gas escapes. until. Excessive thionyl chloride was recovered by distillation, and distillation was continued to collect 67.1g of n-heptanoyl chloride, with a yield of 93%, bp: 173°C. Add 80.1g anhydrous aluminum trichloride (0.6mol) and 125mL benzene (1.4mol) into a 250mL three-necked flask, stir and cool to below 5°C, and start adding 61.93mL (0.4mol) n-heptanoyl chloride dropwise, keeping the temperature low At 10°C, complete the dropwise addition within 1 hour.

2) React at 20°C for 0.5h, and heat in water bath to 40~50°C until no hydrogen chloride escapes. Cool with ice water, pour 250g of water to dilute, use dilute hydrochloric acid to decompose the complex, and place it into layers. Separate the oil layer, extract the water layer with ether, combine the ether layer with the oil layer, wash with water, sodium hydroxide with w=0.10, and water in sequence, dry the oil layer with calcium chloride, filter, evaporate the ether and excess benzene, and distill under reduced pressure , collect the 155°C/2.0kPa fraction to obtain 63.2g of n-heptanoylbenzophenone, with a yield of 83.2%.

3) Add 67.2g (1.2mol) potassium hydroxide, 57g n-heptanophenone (0.3mol), 45g (0.9mol) hydrazine hydrate with w=0.85 and 150mL triethylene glycol into a 500mL three-necked flask. . Stir and heat to reflux. After reflux reaction for 2 hours, use a water separator to separate water and raise the temperature. Raise the temperature to 195°C within 2 hours and reflux for 4 hours. After the reaction is completed, cool to room temperature, add 250 mL of water to dilute, and let stand to separate layers. The aqueous layer is extracted three times with diethyl ether. The diethyl ether extract is combined with the organic layer, and washed twice with dilute hydrochloric acid and water respectively. The organic layer was dried with calcium chloride, filtered, and the ether was evaporated and then distilled under reduced pressure to obtain 43.98 g of n-heptylbenzene, yield 83.3%, bp: 233°C.

4) Add 10g anhydrous aluminum trichloride (67.4mmol) and 27mL methylene chloride into a 150mL three-necked flask, stir and cool; add 17.1g (134mmol) oxalyl chloride dropwise within 5min at 4 to 6°C. Then, a mixture of 11.9g n-heptylbenzene (67.5mmol) and 40mL dry methylene chloride was added dropwise within 1 hour at about 5°C, reacted at 25°C for 2 hours, cooled the mixture to 0°C, and slowly poured in 7.5g while stirring. To a mixture of calcium chloride and 170g of crushed ice, keep the temperature below -5°C during the addition process, and immediately separate the organic layer. Dry over anhydrous sodium sulfate, filter, and evaporate the solvent under reduced pressure. Dissolve the residual liquid in 50 mL of diethyl ether, cool to 0°C, and wash with potassium hydroxide with w=0.05 and water in sequence. The organic layer is washed with anhydrous sodium sulfate and water in sequence. 0.4nm molecular sieve drying. Filter, evaporate the solvent and then distill under reduced pressure. Collect the fraction at 138~140℃/133Pa to obtain 10.6g of 4-n-heptylbenzoyl chloride with a yield of 66.0%.