2-Nitrobenzaldehyde
| |
| Names | |
|---|---|
| IUPAC name
2-Nitrobenzaldehyde
| |
| Properties | |
| C7H5NO3 | |
| Appearance | Pale yellow crystalline powder |
| Melting point | 43 °C (109 °F; 316 K) |
| Boiling point | 152 °C (306 °F; 425 K) |
| Insoluble | |
| Hazards | |
| Occupational safety and health (OHS/OSH): | |
Main hazards
|
Harmful, Potentially mutagenic |
| NFPA 704 (fire diamond) | |
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
| |
2-Nitrobenzaldehyde, ortho-nitrobenzaldehyde or o-nitrobenzaldehyde is an organic aromatic compound containing a nitro group ortho to an aldehyde. 2-Nitrobenzaldehyde finds use as an intermediate in the synthesis of the widely used dye Indigo.[3]
Synthesis
The synthesis of 2-nitrobenzaldehyde via nitration of benzaldehyde is problematic because this produces mostly 3-nitrobenzaldehyde, with yields being about 19% for the ortho-, 72% for the meta- and 9% for the para isomer.[4] For this reason, the nitration of benzaldehyde to yield 2-nitrobenzaldehyde is not cost-effective.
- In one synthetic process, toluene is mono-nitrated at cold temperatures to 2-nitrotoluene, with about 58% being converted to the ortho- isomer, the remaining forming meta- and para- isomers.[5] The 2-nitrotoluene can then be oxidized to yield 2-nitrobenzaldehyde.[6][7]
- Another potential method of production is the oxidative cleavage of 2-nitrostyrene. Cinnamaldehyde is nitrated in a solution of acetic anhydride in acetic acid, in high-yield to 2-nitrocinnamaldehyde.[8] This is then oxidized to 2-nitrocinnamic acid and decarboxylated to the 2-nitrostyrene. The ethylene group can be oxidized in a number of different ways to yield 2-nitrobenzaldehyde.[9]
Uses
2-Nitrobenzaldehyde is an intermediate chemical for the synthesis of Indigo, a water-insoluble dye commonly used to dye jeans and other fabrics. In the Baeyer-Drewson indigo synthesis, two moles of 2-nitrobenzaldehyde condenses with two moles of acetone in basic aqueous solution to yield one mole of indigo in a one-pot synthesis.[10][11][12][13]
Baeyer-Drewson Indigo Synthesis
2-Nitrobenzaldehyde is a potential starting material for other chemicals as well, given the two relatively reactive groups attached to an aryl system.
Substituted 2-nitrobenzaldehydes can also be used to yield other important compounds based on indigo, such as Indigo carmine.
References
- ^ 2-Nitrobenzaldehyde
- ^ 2-Nitrobenzaldehyde MSDS
- ^ http://en.wikipedia.org/wiki/Baeyer-Drewson_indigo_synthesis Baeyer-Drewson Indigo Synthesis
- ^ Structure of Benzene, California State University Dominguez Hills
- ^ http://www.thecatalyst.org/experiments/AndersonS/AndersonS.html Product Distribution in the Nitration of Toluene, Steven W. Anderson, January 7, 1999
- ^ Synthesis of 2-Nitrobenzaldehyde from 2-Nitrotoluene, Alexander Popkov
- ^ "o-Nitrobenzaldehyde". Archived from the original on 2009-07-23. Retrieved 2009-07-21.
{{cite web}}: Unknown parameter|deadurl=ignored (|url-status=suggested) (help) - ^ o-NITROCINNAMALDEHYDE, nitration of cinnamaldehyde, organic-synthesis
- ^ Selective aerobic oxidation of styrene to benzaldehyde catalyzed by water-soluble palladium(II) complex in water, Bo Feng, Zhenshan Hou, Xiangrui Wang, Yu Hu, Huan Li and Yunxiang Qiao
- ^ http://en.wikipedia.org/wiki/Baeyer-Drewson_indigo_synthesis Baeyer-Drewson Indigo Synthesis
- ^ Synthesis of Indigo
- ^ Indigo Synthesis
- ^ Synthesis of Indigo and Vat Dyeing