Hexyl Cinnamic Aldehyde HCA Aroma Chemical
CAS# 101-86-0

Hexyl Cinnamic Aldehyde-often abbreviated as HCA and also known by chemical names such as alpha-hexylcinnamaldehyde and 2-(phenylmethylene)octanal-is a fully synthetic fragrance ingredient. Although its structure mimics naturally occurring compounds, this material is manufactured industrially via an aldol condensation between the fatty aldehyde octanal and benzaldehyde. Presenting as a clear, oil-based liquid ranging in color from pale yellow to a more pronounced yellow, HCA carries a jasmine-like scent with faint nuances of fatty/oily, waxy, and lightly herbaceous notes. Its history began when chemists sought an improved version of Amyl Cinnamic Aldehyde (ACA), which was discovered in 1923. The result was HCA, offering a lighter, more airy jasmine character with less greasy nuance than ACA, and exceptional stability in harsh media such as high-pH soaps and detergents, making it one of the most widely used fragrance materials worldwide today.

Description

Belonging to the floral family with a jasmine signature and a green-herbal facet, HCA operates from the heart to base of a composition. It functions as a blending material and a fixative thanks to its low vapor pressure, and it is also a highly useful odor modifier in formulas. Rather than projecting the sparkle of fresh flowers, HCA leans toward a waxy, oily, green-herbal direction, giving a soft, subdued impression with medium to low intensity. In exchange, its substantivity is excellent-it lasts a long time on blotters and is exceptionally durable on fabrics. In compounding, it is considered a backbone for building jasmine and gardenia accords: it adds body, creates a foundation, and links other floral materials together, while partially replacing expensive natural jasmine oil. A classic approach is combining HCA with benzyl acetate and indole: benzyl acetate provides diffusion, indole contributes the characteristic animalic nuance, and HCA builds the “body” and long-lasting structure of the artificial flower. Because it is a user-friendly liquid, HCA is often used neat, but it should always be supplied/used with an antioxidant.

Applications

Its largest use is in detergents and fabric care (laundry powders, fabric softeners) due to its low cost and outstanding lasting power. It is also widely used in cosmetics, including bar soaps, shower gels, shampoos, and most floral perfumes. HCA has a flexible dosage range-typically 2% to 30% within fragrance compounds and it can be very high in fabric softeners-however, the concentration in the finished consumer product is always subject to IFRA limits. From a safety standpoint, it appears in the EU’s list of 26 fragrance allergens requiring labeling (and similarly in many other markets). Because it oxidizes readily on exposure to air-forming byproducts that can irritate skin-commercial HCA is commonly stabilized with antioxidants such as BHT or tocopherol (vitamin E). Users should store it in a tightly sealed, dark container, away from light and high temperatures. In the market, it is difficult to single out one specific perfume because HCA appears in thousands of classic and modern products, but its heavy use is easy to recognize in floral fabric softeners such as Downy or Comfort. Finally, in entry 1609 of Perfume and Flavor Chemicals, expert Steffen Arctander described HCA as jasmine-like with a green-herbal tone-light yet persistent-and noted it is often preferred over ACA because it is more distinctly floral and less greasy, emphasizing that it is among the most frequently used perfume chemicals, present in nearly all types of floral fragrances and essential to jasmine and gardenia bases.