Benzyl chloride

Benzyl chloride
Benzyl chloride
Names
	Preferred IUPAC name (Chloromethyl)benzene
	Other names α-Chlorotoluene; Benzyl chloride; alpha-chlorophenylmethane
Identifiers
CAS Number	100-44-7 ;
3D model (JSmol)	Interactive image;
Abbreviations	BnCl
ChEBI	CHEBI:615597 ;
ChEMBL	ChEMBL498878 ;
ChemSpider	13840690 ;
ECHA InfoCard	100.002.594
EC Number	202-853-6;
KEGG	C19167 ;
PubChem CID	7503;
UNII	83H19HW7K6 ;
CompTox Dashboard (EPA)	DTXSID0020153 ;
	InChI InChI=1S/C7H7Cl/c8-6-7-4-2-1-3-5-7/h1-5H,6H2 Key: KCXMKQUNVWSEMD-UHFFFAOYSA-N ; InChI=1/C7H7Cl/c8-6-7-4-2-1-3-5-7/h1-5H,6H2 Key: KCXMKQUNVWSEMD-UHFFFAOYAV;
	SMILES ClCc1ccccc1;
Properties
Chemical formula	C7H7Cl
Molar mass	126.58 g·mol−1
Appearance	Colorless to slightly yellow, toxic liquid
Odor	Pungent, aromatic
Density	1.100 g/cm3
Melting point	−39 °C (−38 °F; 234 K)
Boiling point	179 °C (354 °F; 452 K)
Solubility in water	very slightly soluble (0.05% at 20 °C)
Solubility	soluble in ethanol, ethyl ether, chloroform, CCl4 ; miscible in organic solvents
Vapor pressure	1 mmHg (20 °C)
Magnetic susceptibility (χ)	-81.98·10−6 cm3/mol
Refractive index (nD)	1.5415 (15 °C)
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Toxic and carcinogenic; lachrymator
NFPA 704 (fire diamond)	3 2 1
Flash point	67 °C (153 °F; 340 K)
Autoignition; temperature	585 °C (1,085 °F; 858 K)
Explosive limits	≥1.1%
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	121 mg/kg (rat, oral)
LC50 (median concentration)	150 ppm (rat, 2 hr); 80 ppm (mouse, 2 hr)
LCLo (lowest published)	380 ppm (dog, 8 hr)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 1 ppm (5 mg/m3)
REL (Recommended)	C 1 ppm (5 mg/m3) [15-minute]
IDLH (Immediate danger)	10 ppm
Safety data sheet (SDS)	External MSDS
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Benzyl chloride, or α-chlorotoluene, is an organic compound with the formula C₆H₅CH₂Cl. This colorless liquid is a reactive organochlorine compound that is a widely used chemical building block.

Preparation

Benzyl chloride is prepared industrially by the gas-phase photochemical reaction of toluene with chlorine:^[3]

C₆H₅CH₃ + Cl₂ → C₆H₅CH₂Cl + HCl

In this way, approximately 100,000 tonnes are produced annually. The reaction proceeds by the free radical process, involving the intermediacy of free chlorine atoms.^[4] Side products of the reaction include benzal chloride and benzotrichloride.

Other methods of production exist, such as the Blanc chloromethylation of benzene. Benzyl chloride was first prepared from treatment of benzyl alcohol with hydrochloric acid.

Uses and reactions

Industrially, benzyl chloride is the precursor to benzyl esters, which are used as plasticizers, flavorants, and perfumes. Phenylacetic acid, a precursor to pharmaceuticals, is produced from benzyl cyanide, which in turn is generated by treatment of benzyl chloride with sodium cyanide. Quaternary ammonium salts, used as surfactants, are readily formed by alkylation of tertiary amines with benzyl chloride.^[3]

Benzyl ethers are often derived from benzyl chloride. Benzyl chloride reacts with aqueous sodium hydroxide to give dibenzyl ether. In organic synthesis, benzyl chloride is used to introduce the benzyl protecting group in reaction with alcohols, yielding the corresponding benzyl ether, carboxylic acids, and benzyl ester.

Benzoic acid (C₆H₅COOH) can be prepared by oxidation of benzyl chloride in the presence of alkaline KMnO₄:

C₆H₅CH₂Cl + 2 KOH + 2 [O] → C₆H₅COOK + KCl + H₂O

Benzyl chloride may be used in the synthesis of amphetamine-class drugs, and for this reason, sales of benzyl chloride are monitored as a List II drug precursor chemical by the US Drug Enforcement Administration.

Benzyl chloride also reacts readily with metallic magnesium to produce a Grignard reagent.^[5] It is preferable over benzyl bromide for the preparation of this reagent, since the reaction of the bromide with magnesium tends to form the Wurtz coupling product 1,2-diphenylethane.

Safety

Benzyl chloride is an alkylating agent. Indicative of its high reactivity (relative to alkyl chlorides), benzyl chloride slowly reacts with water in a hydrolysis reaction to form benzyl alcohol and hydrochloric acid. In contact with mucous membranes, hydrolysis produces hydrochloric acid. Thus, benzyl chloride is a lachrymator and has been used in chemical warfare. It is also very irritating to the skin.

It is classified as an extremely hazardous substance in the United States as defined in Section 302 of the U.S. Emergency Planning and Community Right-to-Know Act (42 U.S.C. 11002), and is subject to strict reporting requirements by facilities which produce, store, or use it in significant quantities.^[6]

References

^ ^a ^b ^c ^d ^e ^f ^g NIOSH Pocket Guide to Chemical Hazards. "#0053". National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b "Benzyl chloride". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).
^ ^a ^b "Chlorinated Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a06_233.pub2. ISBN 978-3527306732.
^ Furniss, B. S.; Hannaford, A. J.; Smith, P. W. G.; Tatchell, A. R. (1989), Vogel's Textbook of Practical Organic Chemistry (5th ed.), Harlow: Longman, p. 864, ISBN 0-582-46236-3
^ Henry Gilman and W. E. Catlin (1941). "n-Propylbenzene". Organic Syntheses; Collected Volumes, vol. 1, p. 471.
^ "40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities" (PDF) (July 1, 2008 ed.). Government Printing Office. Archived from the original (PDF) on February 25, 2012. Retrieved October 29, 2011.

External links

[PGCH-1] ^ ^a ^b ^c ^d ^e ^f ^g NIOSH Pocket Guide to Chemical Hazards. "#0053". National Institute for Occupational Safety and Health (NIOSH).

[IDLH-2] "Benzyl chloride". Immediately Dangerous to Life or Health Concentrations (IDLH). National Institute for Occupational Safety and Health (NIOSH).

[Ullmann-3] "Chlorinated Hydrocarbons". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a06_233.pub2. ISBN 978-3527306732.

[4] Furniss, B. S.; Hannaford, A. J.; Smith, P. W. G.; Tatchell, A. R. (1989), Vogel's Textbook of Practical Organic Chemistry (5th ed.), Harlow: Longman, p. 864, ISBN 0-582-46236-3

[5] Henry Gilman and W. E. Catlin (1941). "n-Propylbenzene". Organic Syntheses; Collected Volumes, vol. 1, p. 471.

[gov-right-know-6] "40 C.F.R.: Appendix A to Part 355—The List of Extremely Hazardous Substances and Their Threshold Planning Quantities" (PDF) (July 1, 2008 ed.). Government Printing Office. Archived from the original (PDF) on February 25, 2012. Retrieved October 29, 2011.

[1]

[2]

[3]

[4]

[5]

[6]