o-Phthalaldehyde
[CAS# 643-79-8]

Identification

• Classification: Chemical reagent >> Organic reagent >> Aromatic aldehyde (containing acetal, hemiacetal)
• Name: o-Phthalaldehyde
• Synonyms: o-Phthalic aldehyde; 1,2-Phthalic dicarboxaldehyde; 1,2-Benzenedicarboxaldehyde; Benzene-1,2-dicarboxaldehyde
• Molecular Formula: C₈H₆O₂
• Molecular Weight: 134.13
• CAS Registry Number: 643-79-8
• EC Number: 211-402-2
• SMILES: C1=CC=C(C(=C1)C=O)C=O

Properties

• Density: 1.2±0.1 g/cm³, Calc.^*
• Melting point: 54-56 °C (Expl.)
• Index of Refraction: 1.623, Calc.^*
• Boiling Point: 266.1±23.0 °C (760 mmHg), Calc.^*
• Flash Point: 98.5±19.6 °C, Calc.^*, 132 °C (Expl.)
• Water solubility: soluble

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS02;GHS05;GHS06;GHS07;GHS08;GHS09 Danger
• Risk Statements: H228-H301-H314-H315-H317-H318-H335-H373-H400-H410
• Safety Statements: P210-P240-P241-P260-P261-P264-P264+P265-P270-P271-P272-P273-P280-P301+P316-P301+P330+P331-P302+P352-P302+P361+P354-P304+P340-P305+P354+P338-P316-P317-P319-P321-P330-P332+P317-P333+P317-P362+P364-P363-P370+P378-P391-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	3	H301
Acute hazardous to the aquatic environment	Aquatic Acute	1	H400
Chronic hazardous to the aquatic environment	Aquatic Chronic	1	H410
Serious eye damage	Eye Dam.	1	H318
Skin sensitization	Skin Sens.	1	H317
Skin corrosion	Skin Corr.	1C	H314
Flammable solids	Flam. Sol.	1	H228
Specific target organ toxicity - repeated exposure	STOT RE	2	H373
Skin corrosion	Skin Corr.	1B	H314
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin sensitization	Skin Sens.	1A	H317
Skin irritation	Skin Irrit.	2	H315
Substances or mixtures corrosive to metals	Met. Corr.	1	H290
Skin corrosion	Skin Corr.	1	H314
Eye irritation	Eye Irrit.	2	H319

Discovery and Applications

o-Phthalaldehyde, with the chemical formula C8H6O2, is an aromatic aldehyde consisting of a benzene ring with two aldehyde groups (-CHO) positioned at the 1 and 2 positions. It is a structural isomer of other phthalaldehyde derivatives, differing in the relative positions of the functional groups on the benzene ring.

The discovery of o-phthalaldehyde dates back to the late 19th century, during the early exploration of aromatic aldehydes. Its synthesis was closely tied to the development of phthalic acid derivatives, which were of significant interest due to their chemical reactivity and potential applications. Over time, o-phthalaldehyde emerged as an important intermediate in organic chemistry.

One of the primary applications of o-phthalaldehyde is as a reagent in chemical synthesis, especially in the formation of other organic compounds. It is used in the preparation of various compounds such as 1,2-diamines through condensation reactions. The aldehyde groups in o-phthalaldehyde are reactive, making the compound a useful building block in synthetic organic chemistry, particularly in the formation of polyfunctional compounds.

Another key application of o-phthalaldehyde is in the synthesis of fluorescent compounds. Its ability to form highly fluorescent derivatives through reactions with amines has made it valuable in analytical and diagnostic chemistry. o-Phthalaldehyde derivatives are often used in the preparation of fluorescent probes, which can be employed in biochemical and medical applications, such as in the detection of specific biomolecules. It has also been used in studies involving protein and enzyme detection, where the fluorescence of its derivatives serves as an indicator of biochemical interactions.

o-Phthalaldehyde is also employed in the preparation of certain types of polymers and materials. By reacting with amines, it can form cross-linked networks, which are useful in the creation of specialized materials with unique properties, such as thermosetting plastics. These materials find applications in various industries, including coatings, adhesives, and electronics.

In addition to its applications in organic synthesis and material science, o-phthalaldehyde is used in the chemical industry for the production of other important chemicals. It serves as an intermediate in the synthesis of phthalimides and other derivatives that are utilized in a wide range of applications, from dyes to pharmaceuticals.

In conclusion, o-phthalaldehyde is a versatile compound with applications in organic synthesis, fluorescent compound preparation, and material science. Its role as an intermediate in the synthesis of more complex organic molecules and its ability to form useful derivatives make it an important chemical in both research and industrial contexts.

References

1979. o-Phthalaldehyde and the fluorogenic detection of peptides. Analytical Biochemistry, 94(2).
DOI: 10.1016/0003-2697(79)90375-0

1984. Measurement of free amino acids in human biological fluids by high-performance liquid chromatography. Journal of Chromatography A, 310.
DOI: 10.1016/s0021-9673(01)89028-2

1994. Measurement of GABA in rat brain microdialysates using o-phthaldialdehyde—sulphite derivatization and high-performance liquid chromatography with electrochemical detection. Journal of Chromatography B: Biomedical Sciences and Applications, 652(2).
DOI: 10.1016/0378-4347(93)e0391-3