Method for synthesizing p-fluorobenzoyl chloride

Abstract

The invention discloses a method for synthesizing p-fluorobenzoyl chloride. The method is characterized by comprising the following steps: adding bis(trichlormethyl) carbonate into a reaction kettle filled with parafluorobenzoic acid and 1,2-dichloroethane, reacting in the presence of a catalyst, filtering, and performing reduced pressure distillation, thereby obtaining p-fluorobenzoyl chloride. The selected acylating chlorination reagents are green and environment-friendly, the raw materials are low in price and readily available, the synthetic process is mild in conditions, the purity of the finally obtained product can be 99.9 percent, and the product has wide application prospects and industrial values.

Description

technical field

[0001] The invention relates to the field of preparation of fluorine-containing intermediates, in particular to a synthetic method of p-fluorobenzoyl chloride. Background technique

[0002] p-Fluorobenzoyl chloride is an important fluorine-containing intermediate and an important intermediate for the synthesis of fluorine-containing drugs flunarizine, lomerizine, and almitrigine. Its special application is that it is a special high-performance engineering plastic An important intermediate of the monomer 4,4'-difluorobenzophenone of polyetheretherketone (PEEK).

[0003] At present, there are many publicly reported routes for the synthesis of p-fluorobenzoyl chloride, mainly as follows: U.S. Patent US 2006 / 12879A1 reports that it is prepared by reacting p-fluorobenzoic acid with thionyl chloride. The shortcoming of this route is the preparation of by-products A large amount of acid gas is produced, which is more corrosive to equipment; U.S. Patent US6187952B1 ...

Examples

Embodiment 1

[0018] Weigh 89.1g (0.3mol) of solid phosgene (BTC) and 63g (0.45mol) of p-fluorobenzoic acid into a three-necked flask, add 500mL of solvent 1.2-dichloroethane, and add 0.3g (0.003mol) of catalyst triethylamine , slowly raising the reaction temperature to 60° C., reacting at this temperature for 4 hours, filtering the reaction solution, removing the solvent, and finally obtaining about 60 g of p-fluorobenzoyl chloride by distillation under reduced pressure, with a yield of 95.1%.

Embodiment 2

[0020] Weigh 89.1g (0.3mol) of solid phosgene (BTC) and 84g (0.6mol) of p-fluorobenzoic acid in a three-necked flask, add 500mL of solvent 1.2-dichloroethane, add 0.24g (0.003mol) of catalyst pyridine, and slowly Raise the temperature of the reaction to 60° C., react at this temperature for 4 hours, filter the reaction solution, remove the solvent, and finally obtain about 75.8 g of p-fluorobenzoyl chloride through vacuum distillation, with a yield of 80.1%.

Embodiment 3

[0022] Weigh 89.1g (0.3mol) of solid phosgene (BTC) and 105g (0.75mol) of p-fluorobenzoic acid in a three-necked flask, add 500mL of solvent 1.2-dichloroethane, add 0.2g (0.003mol) of catalyst imidazole, and slowly Raise the reaction temperature to 60°C, react at this temperature for 4 hours, filter the reaction solution, remove the solvent, and finally obtain about 100.6 g of p-fluorobenzoyl chloride by distillation under reduced pressure, with a yield of 85.0%.

technical field

[0001] The invention relates to the field of preparation of fluorine-containing intermediates, in particular to a synthetic method of p-fluorobenzoyl chloride. Background technique

[0002] p-Fluorobenzoyl chloride is an important fluorine-containing intermediate and an important intermediate for the synthesis of fluorine-containing drugs flunarizine, lomerizine, and almitrigine. Its special application is that it is a special high-performance engineering plastic An important intermediate of the monomer 4,4'-difluorobenzophenone of polyetheretherketone (PEEK).

[0003] At present, there are many publicly reported routes for the synthesis of p-fluorobenzoyl chloride, mainly as follows: U.S. Patent US 2006 / 12879A1 reports that it is prepared by reacting p-fluorobenzoic acid with thionyl chloride. The shortcoming of this route is the preparation of by-products A large amount of acid gas is produced, which is more corrosive to equipment; U.S. Patent US6187952B1 ...

Examples

Embodiment 1

[0018] Weigh 89.1g (0.3mol) of solid phosgene (BTC) and 63g (0.45mol) of p-fluorobenzoic acid into a three-necked flask, add 500mL of solvent 1.2-dichloroethane, and add 0.3g (0.003mol) of catalyst triethylamine , slowly raising the reaction temperature to 60° C., reacting at this temperature for 4 hours, filtering the reaction solution, removing the solvent, and finally obtaining about 60 g of p-fluorobenzoyl chloride by distillation under reduced pressure, with a yield of 95.1%.

Embodiment 2

[0020] Weigh 89.1g (0.3mol) of solid phosgene (BTC) and 84g (0.6mol) of p-fluorobenzoic acid in a three-necked flask, add 500mL of solvent 1.2-dichloroethane, add 0.24g (0.003mol) of catalyst pyridine, and slowly Raise the temperature of the reaction to 60° C., react at this temperature for 4 hours, filter the reaction solution, remove the solvent, and finally obtain about 75.8 g of p-fluorobenzoyl chloride through vacuum distillation, with a yield of 80.1%.

Embodiment 3

[0022] Weigh 89.1g (0.3mol) of solid phosgene (BTC) and 105g (0.75mol) of p-fluorobenzoic acid in a three-necked flask, add 500mL of solvent 1.2-dichloroethane, add 0.2g (0.003mol) of catalyst imidazole, and slowly Raise the reaction temperature to 60°C, react at this temperature for 4 hours, filter the reaction solution, remove the solvent, and finally obtain about 100.6 g of p-fluorobenzoyl chloride by distillation under reduced pressure, with a yield of 85.0%.