Hexadecanal
[CAS# 629-80-1]

Identification

• Classification: Chemical reagent >> Organic reagent >> Fatty aldehyde (containing acetal, hemiacetal)
• Name: Hexadecanal
• Molecular Formula: C₁₆H₃₂O
• Molecular Weight: 240.42
• CAS Registry Number: 629-80-1
• EC Number: 211-111-0
• SMILES: CCCCCCCCCCCCCCCC=O

Properties

• Density: 0.8±0.1 g/cm³ Calc.^*
• Melting point: 35 ºC (Expl.)
• Boiling point: 297.8±3.0 ºC 760 mmHg (Calc.)^*, 68.4 ºC (Expl.)
• Flash point: 138.9±6.0 ºC (Calc.)^*
• Index of refraction: 1.44 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Hazard Statements: H315-H319-H335
• Precautionary Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Skin irritation	Skin Irrit.	2	H315
Specific target organ toxicity - single exposure	STOT SE	3	H335

Discovory and Applicatios

Hexadecanal is a long-chain aliphatic aldehyde with the molecular formula C₁₆H₃₂O. It consists of a straight 16-carbon saturated chain terminated by an aldehyde functional group. Structurally, it is categorized as a fatty aldehyde, and it serves as an important intermediate in lipid metabolism and chemical synthesis. This compound is also known by its common name, palmitaldehyde, reflecting its close relation to palmitic acid, from which it is often derived through oxidation.

The discovery and characterization of hexadecanal are rooted in early studies on natural lipids and fatty acid derivatives. It was first identified as a product of fatty acid metabolism in various organisms, including mammals, where fatty acids undergo enzymatic transformation by aldehyde-forming oxidases. Its natural occurrence in biological systems has made it a subject of interest in biochemistry and physiology, particularly in the context of lipid signaling and metabolism.

In biological systems, hexadecanal plays a role as an intermediate in the synthesis and degradation of sphingolipids. Sphingolipid metabolism involves the conversion of sphingosine-1-phosphate and other related compounds, during which hexadecanal can be formed. It is involved in peroxisomal and microsomal pathways of fatty acid degradation and may participate in lipid-derived signaling events. Its aldehyde functional group makes it reactive, allowing it to participate in redox reactions or form Schiff bases with amino groups, which can have downstream effects on proteins and membranes.

In the field of chemical synthesis, hexadecanal is utilized as a starting material or intermediate for the production of various derivatives, including long-chain alcohols, amines, and surfactants. It can be reduced to hexadecanol (cetyl alcohol), a widely used emollient in cosmetics and personal care products. Alternatively, it can be used to synthesize long-chain aldimines and oximes for use in chemical and pharmaceutical industries. The reactivity of the aldehyde group allows it to be used in condensation and polymerization reactions to create specialty materials.

Hexadecanal is also studied in the context of olfactory research. Long-chain aldehydes, including hexadecanal, are components of natural odors and pheromones in some animals. Their role in chemical communication, although not fully understood, is under investigation in mammalian models where volatile fatty aldehydes may influence social or reproductive behaviors.

In industrial applications, hexadecanal serves as a precursor to surfactants and lubricants. Its derivatives are found in detergents, textile softeners, and specialty lubricants. Because of its relatively high melting point and solid-state at room temperature, it is processed using heat or solvents during manufacturing. The controlled oxidation of palmitic acid or the partial reduction of palmityl chloride are typical synthetic routes to obtain high-purity hexadecanal for industrial use.

Analytically, hexadecanal can be identified and quantified using chromatographic methods such as gas chromatography coupled with mass spectrometry (GC-MS), often after derivatization to stabilize the aldehyde group. Its characterization includes standard techniques such as infrared spectroscopy, where the aldehyde C=O stretch appears prominently, and NMR spectroscopy for structural elucidation.

Hexadecanal remains a significant compound in both fundamental biochemical studies and applied chemical industries. Its dual identity as a biological intermediate and industrial precursor continues to support a wide range of research and product development efforts. The balance between its natural function and synthetic utility illustrates its value in bridging the gap between biological and chemical sciences.

References

1986. Modulation of myelin basic protein-induced aggregation and fusion of liposomes by cholesterol, aliphatic aldehydes and alkanes. Biochimica et Biophysica Acta (BBA) - Biomembranes, 862(2).
DOI: 10.1016/0005-2736(86)90385-8

2005. Antennal lobe projection destinations of Helicoverpa zea male olfactory receptor neurons responsive to heliothine sex pheromone components. Journal of Comparative Physiology A, 191(11).
DOI: 10.1007/s00359-005-0071-8

2016. Identification of long chain specific aldehyde reductase and its use in enhanced fatty alcohol production in E. coli. Metabolic Engineering, 37.
DOI: 10.1016/j.ymben.2016.04.003