Benzoyl chloride
Benzoyl chloride, also known as benzoyl chloride and benzoyl chloride, is a type of acid chloride. The pure product is a colorless, transparent and flammable liquid that emits smoke when exposed to air. The industrial product is slightly light yellow in color and has a strong pungent odor. The steam has a strong irritating effect on the eye mucosa, skin and respiratory tract, and induces tears by stimulating the eye mucosa. Soluble in ether, chloroform, benzene and carbon disulfide. It gradually decomposes when exposed to water, ammonia or ethanol to produce benzoic acid, benzamide or ethyl benzoate and hydrogen chloride. In the laboratory, it can be obtained by distilling benzoic acid and phosphorus pentachloride under anhydrous conditions.
Industrial preparation methods can be obtained by chlorinating benzaldehyde using thionyl chloride. Benzoyl chloride is an important intermediate in the preparation of dyes, fragrances, organic peroxides, pharmaceuticals and resins. It is also used in photography and the production of artificial tannic acid, and has been used as an irritant gas in chemical warfare.
Preparation of amides
The preparation methods of amides include: condensation acylation reaction of carboxylic acid and amine, acylation reaction of ammonia or amine and acid halide, acylation reaction of ammonia or amine and acid anhydride, other condensation methods, transesterification to amide, amide The radical is converted to amide.
The reaction between benzoyl chloride and ammonia belongs to the acylation reaction of ammonia or amine and acid halide, and is a preparation method of benzamide. The simplest way to synthesize amides is the interaction of acid halides (acyl chlorides, acyl fluorides, and acyl fluorides) with ammonia or amines. Acyl chlorides and acid bromides can react quickly with aliphatic and aromatic amines to generate amides with high yields. However, acyl fluoride is relatively stable to water and other nucleophiles. Generally, the reaction between acid chloride, acid bromide and amine is exothermic and sometimes even extremely violent. Therefore, the reaction is usually carried out under ice cooling. A certain amount of solvent can also be used to slow down the reaction speed.
Commonly used solvents are dichloroethane, ether, carbon tetrachloride, toluene, etc. Since the hydrogen halide is generated during the reaction, it is necessary to remove the hydrogen halide with a base to prevent it from forming a salt with the amine. Both organic bases and inorganic bases can be used in this type of reaction. Commonly used organic bases include triethylamine, pyridine, etc. Commonly used inorganic bases include Na2CO3, NaHCO3, K2CO3, NaOH, KOH, etc. In our research we found that many reactions are cleaner and easier to handle with inorganic bases. For some aromatic amines with large steric hindrance and low activity, the reaction may not occur even if acid chloride is used. At this time, we need to add a catalyst such as DMAP, etc. Sometimes it can also be obtained directly from the high-temperature reflux reaction of amine and amide without adding any base.
Reaction of benzoyl chloride and ammonia
This is the preparation method of benzoyl amide. First, add ammonium carbonate and ammonia water with a relative density of less than 0.905 in a glass-lined reaction pot, stir, and drop benzoyl chloride below 40°C. After the addition is complete, stir for another 30 minutes until the smell of benzoyl chloride disappears. Filter the crude product; wash with water; recrystallize with distilled water to obtain benzamide.
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