|Jmol-3D images||Image 1|
|Molar mass||151.12 g/mol|
|Appearance||Pale yellow crystalline powder|
|Melting point||43 °C; 109 °F; 316 K|
|Boiling point||152 °C; 306 °F; 425 K|
|Solubility in water||Insoluble|
|R-phrases||R36 R37 R38 R41|
|Main hazards||Harmful, Potentially mutagenic|
| (what is: / ?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
The main routes to nitrobenzaldehyde begin with the nitration of styrene and cinnamic acid followed by the conversions of the resulting 2-nitrostyrene and 2-nitrocinnamic acids. Cinnamaldehyde can also be nitrated, e.g. in a solution of acetic anhydride in acetic acid, in high-yield to 2-nitrocinnamaldehyde. This compound is then oxidized to 2-nitrocinnamic acid, which is decarboxylated to the 2-nitrostyrene. The vinyl group can be oxidized in a number of different ways to yield 2-nitrobenzaldehyde.
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. The 2-nitrotoluene can then be oxidized to yield 2-nitrobenzaldehyde.
Alternatively, 2-nitrotoluene as formed above can be halogenated to a 2-nitrobenzyl halide followed by oxidation with DMSO and sodium bicarbonate to yield 2-nitrobenzaldehyde, which is subsequently purified with the creation of a bisulfite adduct.
The nitration of benzaldehyde produces mostly 3-nitrobenzaldehyde, with yields being about 19% for the ortho-, 72% for the meta- and 9% for the para isomer. For this reason, the nitration of benzaldehyde to yield 2-nitrobenzaldehyde is not cost-effective.
2-Nitrobenzaldehyde is an intermediate in an early route to Indigo, a water-insoluble dye commonly used to dye jeans and other fabrics. In the Baeyer-Drewson indigo synthesis, 2-nitrobenzaldehyde condenses with acetone in basic aqueous solution to yield indigo in a one-pot synthesis. The method was abandoned in the early part of the 20th century, being replaced by routes from aniline.
Given its two relatively reactive groups, 2-nitrobenzaldehyde is a potential starting material for other compounds. Substituted 2-nitrobenzaldehydes can also be used to yield other important compounds based on indigo, such as Indigo carmine.
- 2-Nitrobenzaldehyde MSDS
- 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://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.
- "Process for the Preparation of 2-Nitrobenzaldehyde". Retrieved 2010-10-18.
- Structure of Benzene, California State University Dominguez Hills
- See Baeyer-Drewson indigo synthesis
- Synthesis of Indigo
- Indigo Synthesis
- Synthesis of Indigo and Vat Dyeing
- Elmar Steingruber "Indigo and Indigo Colorants" Ullmann's Encyclopedia of Industrial Chemistry 2004, Wiley-VCH, Weinheim. doi: 10.1002/14356007.a14_149.pub2
- Peter Šebej, Tomáš Šolomek, Ľubica Hroudná, Pavla Brancová and Petr Klán: J. Org. Chem., 2009, 74 (22), pp 8647–8658; doi: 10.1021/jo901756r