Aldehyde C-11 MOA aka. 2-Methyl Decanal Aroma Chemical
CAS# 19009-56-4

2-Methyldecanal, also widely known in the flavor and fragrance industry as Aldehyde C-11 MOA or Methyl Octyl Acetaldehyde (CAS Number: 19009-56-4, Molecular Formula: C11H22O), is a potent branched aliphatic aldehyde. This compound typically appears as a clear, colorless to pale yellow liquid. Structurally, the presence of the alpha-methyl group makes 2-Methyldecanal significantly more stable than its straight-chain counterparts (such as Decanal or Aldehyde C-10) against oxidation and alkali degradation. Due to its hydrophobic nature, it has limited solubility in water but dissolves readily in oils and organic solvents.

The product's most distinctive feature is its intense aldehydic, waxy, and citrus-like (orange peel) odor profile, accompanied by a fresh metallic nuance and subtle amber undertones. Perfumers value this compound for its ability to deliver a "clean linen" freshness and add a radiant, complex character to fragrance formulations. Because of its remarkable diffusive power and high odor intensity, Aldehyde C-11 MOA is used exclusively in trace amounts, and it is generally recommended to be evaluated at dilutions of 1% or lower.

In industrial manufacturing, 2-Methyldecanal is an incredibly versatile raw material. Its superior stability makes it an ideal choice for high-pH environments, including soaps, laundry detergents, and fabric softeners. It is also widely used in a variety of personal care products, cosmetics, and air care applications. Notably, this compound serves as a core active ingredient in malodor counteractant compositions. When combined with other specific materials, it creates a synergistic effect that successfully neutralizes and blocks unpleasant smells such as urine, sweat, body odor, and pet odors.

To ensure optimal quality, the product must be stored in a cool, dry place, protected from heat and light. During storage, it should be kept in tightly sealed containers (preferably aluminum or glass) under an inert blanket of nitrogen gas; this prevents oxidation into corresponding carboxylic acids, which can otherwise result in a rancid or sour off-odor. Finally, the concentration and dosage of Aldehyde C-11 MOA in finished consumer products must strictly adhere to the safety guidelines and usage limits established by the International Fragrance Association (IFRA).