p-Tolualdehyde
[CAS# 104-87-0]

Identification

• Classification: Flavors and spices >> Synthetic spice >> Aldehyde fragrance >> Aromatic aldehyde
• Name: p-Tolualdehyde
• Synonyms: 4-Methylbenzaldehyde
• Molecular Formula: C₈H₈O
• Molecular Weight: 120.15
• CAS Registry Number: 104-87-0
• EC Number: 203-246-9
• SMILES: CC1=CC=C(C=C1)C=O

Properties

• Water solubility: 0.25 g/L (25 °C)
• Density: 1.0±0.1 g/mL, Calc.^*, 1.018 g/mL (Expl.)
• Melting point: -6 °C (Expl.)
• Index of Refraction: 1.558, Calc.^*, 1.544-1.548 (Expl.)
• Boiling Point: 204.5 °C (760 mmHg), Calc.^*, 204-205 °C (Expl.)
• Flash Point: 80.0 °C, Calc.^*, 80 °C (Expl.)

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H319
• Safety Statements: P264-P264+P265-P270-P280-P301+P317-P305+P351+P338-P330-P337+P317-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Acute toxicity	Acute Tox.	4	H302
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335
Eye irritation	Eye Irrit.	2A	H319
Flammable liquids	Flam. Liq.	4	H227
Acute toxicity	Acute Tox.	4	H312

Discovery and Applications

p-Tolualdehyde, also known as 4-methylbenzaldehyde, is an organic compound with the chemical formula C8H8O. It is an aromatic aldehyde and consists of a benzene ring with a methyl group (-CH3) at the para position and an aldehyde group (-CHO) at the 1-position. This compound is a colorless to pale yellow liquid with a characteristic almond-like odor.

The discovery of p-tolualdehyde dates back to the early 19th century when it was first isolated from the distillation of toluene. Toluene, a common industrial solvent, is derived from petroleum and natural gas, and its derivative, p-tolualdehyde, is one of the products formed during the oxidation process of toluene.

p-Tolualdehyde is widely used in the fragrance and flavor industry due to its distinct odor. It is commonly employed as a key ingredient in perfumes, soaps, and other scented products. Its almond-like aroma makes it suitable for use in both floral and fruity fragrance compositions. Additionally, it is used in the preparation of synthetic flavors, particularly in products such as candies, baked goods, and beverages.

Another major application of p-tolualdehyde is in the production of chemical intermediates. It serves as a precursor in the synthesis of various chemicals, including pharmaceuticals, agricultural chemicals, and dyes. In particular, p-tolualdehyde is involved in the synthesis of p-tolylamine and other related compounds, which are used in the manufacture of dyes and pigments.

The compound is also used in organic synthesis, especially in the creation of various functionalized aromatic compounds. p-Tolualdehyde can undergo reactions such as nucleophilic substitution and reduction, allowing for the synthesis of other valuable organic materials.

In terms of safety, p-tolualdehyde is considered to have relatively low toxicity. However, like other aldehydes, it can be irritating to the eyes and respiratory system in higher concentrations. Adequate ventilation and proper handling are recommended when working with this chemical.

In summary, p-tolualdehyde is a valuable aromatic aldehyde with established uses in the fragrance and flavor industries, as well as in the production of chemical intermediates. Its pleasant almond-like aroma and utility in organic synthesis make it a versatile compound in both industrial and consumer products.

References

1979. Determination of Aliphatic and Aromatic Aldehydes in Polluted Airs as their 2,4-Dinitrophenylhydrazones by High Performance Liquid Chromatography. Journal of Chromatographic Science, 17(5), 264.
DOI: 10.1093/chromsci/17.5.264

2018. Volatile metabolomic signature of bladder cancer cell lines based on gas chromatography-mass spectrometry. Metabolomics: Official journal of the Metabolomic Society, 14(5), 1361.
DOI: 10.1007/s11306-018-1361-9

2020. Chemical profiling of the human skin surface for malaria vector control via a non-invasive sorptive sampler with GC×GC-TOFMS. Analytical and Bioanalytical Chemistry, 412(23), 2799.
DOI: 10.1007/s00216-020-02799-y