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Benzoyl chloride, also known as benzenecarbonyl chloride, is an organochlorine compound with the formula C6H5COCl. It is a colourless, fuming liquid with an irritating odour. It is mainly useful for the production of peroxides but is generally useful in other areas such as in the preparation of dyes, perfumes, pharmaceuticals, and resins.

Benzoyl chloride
Benzoyl Chloride
Preferred IUPAC name
Benzoyl chloride
3D model (JSmol)
ECHA InfoCard 100.002.464
RTECS number
  • DM6600000
Molar mass 140.57 g·mol−1
Appearance colorless liquid
Odor Benzaldehyde like but more pungent
Density 1.21 g/mL, liquid
Melting point −1 °C (30 °F; 272 K)
Boiling point 197.2 °C (387.0 °F; 470.3 K)
-75.8·10−6 cm3/mol
Safety data sheet Fisher Scientific MSDS
Toxic T Corrosive C
R-phrases (outdated) R34
S-phrases (outdated) (S1/2) S26 S45
NFPA 704
Flammability code 2: Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38 and 93 °C (100 and 200 °F). E.g. diesel fuelHealth code 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasReactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g. liquid nitrogenSpecial hazards (white): no codeNFPA 704 four-colored diamond
Flash point 72 °C (162 °F; 345 K)
Related compounds
Related compounds
benzoic acid, benzoic anhydride, benzaldehyde
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references


Benzoyl chloride is produced from benzotrichloride using either water or benzoic acid:[1]

C6H5CCl3 + H2O → C6H5COCl + 2 HCl
C6H5CCl3 + C6H5CO2H → 2 C6H5COCl + HCl

As with other acyl chlorides, it can be generated from the parent acid and other chlorinating agents phosphorus pentachloride or thionyl chloride. It was first prepared by treatment of benzaldehyde with chlorine.[2]

An early method for production of benzoyl chloride involved chlorination of benzyl alcohol.[3]


It reacts with water to produce hydrochloric acid and benzoic acid:

C6H5COCl + H2O → C6H5CO2H + HCl

Benzoyl chloride is a typical acyl chloride. It reacts with alcohols to give the corresponding esters. Similarly, it reacts with amines to give the amide.[4][5]

It undergoes the Friedel-Crafts acylation with aromatic compounds to give the corresponding benzophenones and related derivatives.[6] With carbanions, it serves again as a source of "PhCO+".[7]

Benzoyl peroxide, a common reagent in polymer chemistry, is produced industrially by treating benzoyl chloride with hydrogen peroxide and sodium hydroxide:[8]

2 C6H5COCl + H2O2 + 2 NaOH → (C6H5CO)2O2 + 2 NaCl + 2 H2O


  1. ^ Takao Maki, Kazuo Takeda “Benzoic Acid and Derivatives” Ullmann's Encyclopedia of Industrial Chemistry 2002, Wiley-VCH, Weinheim. doi: 10.1002/14356007.a03_555
  2. ^ Friedrich Wöhler, Justus von Liebig (1832). "Untersuchungen über das Radikal der Benzoesäure". Annalen der Pharmacie. 3 (3): 262–266. doi:10.1002/jlac.18320030302. hdl:2027/hvd.hxdg3f.
  3. ^ US1851832, 29 March 1932
  4. ^ C. S. Marvel And W. A. Lazier "Benzoyl Piperidine" Org. Synth. 1929, volume 9, pp. 16. doi:10.15227/orgsyn.009.0016
  5. ^ Prasenjit Saha, Md Ashif Ali, and Tharmalingam Punniyamurthy "Ligand-free Copper(ii) Oxide Nanoparticles Catalyzed Synthesis Of Substituted Benzoxazoles" Org. Synth. 2011, volume 88, pp. 398. doi:10.15227/orgsyn.088.0398. (an illustrative reaction of an amine with benzoyl chloride).
  6. ^ Wesley Minnis "Phenyl Thienyl Ketone" Org. Synth. 1932, vol. 12, pp. 62. doi:10.15227/orgsyn.012.0062
  7. ^ M. Fujita and T. Hiyama "Directed Reduction of a beta-keto Amide: Erythro-1-(3-hydroxy-2-methyl-3-phenylpropanoyl)piperidine" Org. Synth. 1990, volume 69, pp. 44. doi:10.15227/orgsyn.069.0044
  8. ^ El-Samragy, Yehia (2004). "Chemical and Technical Assessment". Benzoyl Peroxide (PDF). 61st JECFA (Technical report). Joint FAO/WHO Expert Committee on Food Additives. p. 1. Retrieved 31 October 2013.

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