Benzal chloride

Structural formula
General
Surname	Benzal chloride
other names	Dichloromethylbenzene Benzylidene chloride Benzyl dichloride Chlorobenzal Phenyl dichloromethane α, α-dichlorotoluene
Molecular formula	C 7 H 6 Cl 2
Brief description	colorless liquid with a pungent odor
External identifiers / databases
CAS number 98-87-3 EC number 202-709-2 ECHA InfoCard 100.002.463 PubChem 7411 Wikidata Q419420
properties
Molar mass	161.03 g mol −1
Physical state	liquid
density	1.26 g cm −3
Melting point	−16 ° C
boiling point	205 ° C
Vapor pressure	0.5 h Pa (20 ° C) 0.9 hPa (30 ° C) 3 hPa (50 ° C)
solubility	very bad in water (200 mg l −1 at 20 ° C)
Refractive index	1,550
safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary danger H and P phrases H: 302-315-318-331-335-351 P: 261-280-305 + 351 + 338-311
MAK	Switzerland: 0.015 ml m −3 or 0.1 mg m −3
Toxicological data	3249 mg kg −1 ( LD 50 ,  rat ,  oral )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions . Refractive index: Na-D line , 20 ° C

Benzal chloride is a chemical compound from the group of aromatic chlorinated halogenated hydrocarbons (more precisely the chlorinated toluene derivatives ). It is in the form of a colorless liquid that fumes slightly in air.

Extraction and presentation

Benzal chloride can be prepared by radical chlorination (radical side chain halogenation) of toluene via benzyl chloride , whereby benzotrichloride is also formed.

${\displaystyle \mathrm {C_{6}H_{5}CH_{3}+Cl_{2}\rightarrow C_{6}H_{5}CH_{2}Cl+HCl} }$

${\displaystyle \mathrm {C_{6}H_{5}CH_{2}Cl+Cl_{2}\rightarrow C_{6}H_{5}CHCl_{2}+HCl} }$

${\displaystyle \mathrm {C_{6}H_{5}CHCl_{2}+Cl_{2}\rightarrow C_{6}H_{5}CCl_{3}+HCl} }$

With an optimized reaction procedure (one works below the boiling point of benzal chloride and chlorination under photochemical conditions in the gas phase), however, practically only benzal chloride is formed.

properties

Chemical properties

Benzaldehyde is formed by hydrolysis of benzal chloride :

${\displaystyle \mathrm {C_{6}H_{5}CHCl_{2}+H_{2}O\rightarrow C_{6}H_{5}CHO+2HCl} }$

Phenylcarbene is formed with strong bases .

Safety-related parameters

Benzal chloride forms flammable vapor-air mixtures at higher temperatures. The compound has a flash point of 88 ° C. The lower explosion limit (LEL) is 1.1 vol.% (75 g / m ³ ). The ignition temperature is 525 ° C. The substance therefore falls into temperature class T1.

use

Benzal chloride is used to make benzaldehyde , cinnamic acid, and others.

proof

Benzal chloride can be detected by gas chromatography .

Individual evidence

1. ↑ ^{a b c d e f g h i j k l m} Entry on alpha, alpha-dichlorotoluene in the GESTIS substance database of the IFA , accessed on September 4, 2018(JavaScript required) .
2. ↑ Benzal chloride data sheet from Sigma-Aldrich , accessed on February 22, 2010 ( PDF ). .
3. ↑ Entry on α, α-dichlorotoluene in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on February 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
4. ↑ Swiss Accident Insurance Fund (Suva): Limits - Current MAK and BAT values (search for 98-87-3 or benzal chloride ), accessed on November 2, 2015.
5. ↑ Benzal chloride data sheet from Acros, accessed on February 22, 2010.
6. ^ Hans Beyer and Wolfgang Walter : Textbook of Organic Chemistry , 19th edition, S. Hirzel Verlag, Stuttgart 1981, ISBN 3-7776-0356-2 .
7. ^ Author collective: Organikum , 22nd edition, Wiley-VCH, Weinheim 2004, ISBN 978-3-527-31148-4 .
8. ↑ Manfred Rossberg, Wilhelm Lendle, Gerhard Pfleiderer, Adolf Tögel, Eberhard-Ludwig Dreher, Ernst Langer, Heinz Rassaerts, Peter Kleinschmidt, Heinz Strack, Richard Cook, Uwe Beck, Karl-August Lipper, Theodore R. Torkelson, Eckhard Löser, Klaus K. Bags: “Chlorinated Hydrocarbons” in Ullmann's Encyclopedia of Chemical Technology, 2007 John Wiley & Sons, New York.
9. ↑ Arbeitsicherheit.de: Procedure for the determination of α, α-dichlorotoluene (benzal chloride)  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. .  

Web links

• Freepatentsonline: Process for the preparation of possibly substituted benzaldehydes (from Benzalchlorid)