Chlorobenzaldehyde
Chlorobenzaldehyde | ||||||
Surname | 2-chlorobenzaldehyde | 3-chlorobenzaldehyde | 4-chlorobenzaldehyde | |||
other names | o -chlorobenzaldehyde | m -chlorobenzaldehyde | p -chlorobenzaldehyde | |||
Structural formula |
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CAS number | 89-98-5 | 587-04-2 | 104-88-1 | |||
PubChem | 6996 | 11477 | 7726 | |||
Molecular formula | C 7 H 5 ClO | |||||
Molar mass | 140.57 g mol −1 | |||||
Physical state | liquid | firmly | ||||
Melting point | 11-14 ° C | 16-18 ° C | 45-47 ° C | |||
boiling point | 212-214 ° C | 213-214 ° C | 213-214 ° C | |||
GHS labeling |
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H and P phrases | 314 | 315-319-335 | 302-315-319-335 | |||
no EUH phrases | no EUH phrases | no EUH phrases | ||||
280-305 + 351 + 338-310 | 261-305 + 351 + 338 | 261-305 + 351 + 338 |
In chemistry, chlorobenzaldehydes are a group of substances that are derived from both benzaldehyde and chlorobenzene . The structure consists of a benzene ring with attached aldehyde group (-CHO) and chlorine (-Cl) as substituents . Their different arrangements ( ortho , meta or para ) result in three constitutional isomers with the empirical formula C 7 H 5 ClO.
presentation
The synthesis of 4-chlorobenzaldehyde can take place starting from 4-chlorotoluene , which is first reacted with phosphorus pentachloride and chlorine under UV radiation. Hydrolysis of the intermediate product obtained in this way, which is doubly chlorinated on the methyl group, with concentrated sulfuric acid leads to 4-chlorobenzaldehyde.
properties
The 4-chlorobenzaldehyde, which has the highest symmetry, has the highest melting point.
use
Chlorobenzaldehydes are used for triphenylmethane dyes and drugs. 4-chlorobenzaldehyde is a basic substance for the synthesis of the pesticides chlorobenzilate , coumachlor , paclobutrazole , triticonazole and uniconazole . Clomazone is obtained from 2-chlorobenzaldehyde .
The 4-chlorobenzaldehyde can also be used to produce 4-fluorobenzaldehyde.
Individual evidence
- ↑ a b c d e f Alfa Aesar catalog 2008/09, p. 445.
- ↑ Data sheet 2-chlorobenzaldehyde from Sigma-Aldrich , accessed on October 16, 2016 ( PDF ).
- ↑ Data sheet 3-Chlorobenzaldehyde from Sigma-Aldrich , accessed on October 16, 2016 ( PDF ).
- ↑ Data sheet 4-chlorobenzaldehyde from Sigma-Aldrich , accessed on October 16, 2016 ( PDF ).
- ^ WL McEwen: p-Chlorbenzaldehyde In: Organic Syntheses . 12, 1932, p. 12, doi : 10.15227 / orgsyn.012.0012 ; Coll. Vol. 2, 1943, p. 133 ( PDF ).
- ↑ Entry on chlorobenzaldehyde. In: Römpp Online . Georg Thieme Verlag, accessed on May 3, 2014.
- ↑ Thomas A. Unger: Pesticide Synthesis Handbook . William Andrew, 1996, ISBN 0-8155-1853-6 , pp. 1028 ( limited preview in Google Book search).
- ↑ http://www.prepchem.com/synthesis-of-4-fluorobenzaldehyde/