C10-20 and C16-18-unsatd fatty acids reaction products with di-Me sulfate-quaternized triethanolamine
[CAS# 91995-81-2]

Identification

• Classification: Surfactant
• Name: C10-20 and C16-18-unsatd fatty acids reaction products with di-Me sulfate-quaternized triethanolamine
• CAS Registry Number: 91995-81-2
• EC Number: 295-344-3

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
Skin irritation	Skin Irrit.	2	H315
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Chronic hazardous to the aquatic environment	Aquatic Chronic	4	H413
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Flammable liquids	Flam. Liq.	2	H226

Discovory and Applicatios

Fatty acids, C10‑20 and C16‑18‑unsaturated, reaction products with di-methyl sulfate‑quaternized triethanolamine are part of the class of quaternary ammonium surfactants commonly referred to as ester quats. These compounds are synthesized by reacting unsaturated fatty acids with triethanolamine to form fatty acid esters, followed by quaternization using dimethyl sulfate to generate the positively charged ammonium center. The fatty acid feedstocks include mixtures of C10‑C20 chain lengths, with C16‑C18 unsaturated chains derived from naturally occurring oils and fats. The quaternization reaction introduces the cationic charge, resulting in a molecule that combines hydrophobic and hydrophilic regions, which is responsible for its surfactant and conditioning properties.

The development of ester quaternary ammonium compounds emerged in the mid-20th century as industrial chemists sought surfactants that offered both conditioning effects and improved biodegradability compared to earlier non-esterified quaternary ammonium compounds. By incorporating ester linkages derived from natural fatty acids, these compounds were designed to retain the surface activity and antimicrobial properties of conventional quats while providing enhanced environmental compatibility. The di-methyl sulfate quaternization method allowed for high conversion to the quaternary ammonium form, ensuring stability, water solubility, and strong interaction with negatively charged surfaces.

Applications of these compounds are primarily in personal care and cosmetic formulations. They are widely used in hair care products such as shampoos, conditioners, and leave-in treatments, where they function as conditioning agents by adsorbing to the hair surface, smoothing the cuticle, and reducing static electricity. Their cationic nature allows them to adhere to negatively charged keratin fibers, improving combability and imparting a soft feel. In skin care products, they are incorporated to enhance emulsification, texture, and skin conditioning, providing a mild and non-irritating effect.

In fabric care, these ester quats are used in fabric softeners, dryer sheets, and textile treatments. The molecules orient on textile fibers with their hydrophobic tails toward the surface and the cationic head groups adhering to the fiber, which reduces static cling and improves softness. This property also makes them valuable in industrial applications where antistatic properties are required, such as in paper processing, leather treatment, and surface coatings.

The environmental profile of these compounds has been a focus of research due to concerns over the persistence of traditional quaternary ammonium compounds. The incorporation of ester linkages allows for hydrolytic cleavage under environmental conditions, facilitating biodegradation while retaining functional performance during use. This balance of efficacy and environmental consideration has contributed to their widespread adoption in consumer and industrial products.

The versatility of these quaternary ammonium compounds extends to their use as emulsifiers and dispersing agents. They can stabilize oil-in-water emulsions and enhance the performance of formulations in which hydrophobic active ingredients are incorporated. Their chemical structure also allows for modification of fatty acid chain lengths to optimize properties for specific applications, such as enhancing mildness for hair care or increasing lubrication for textile treatment.

The industrial production of fatty acids, C10‑20 and C16‑18-unsaturated, reaction products with di-methyl sulfate-quaternized triethanolamine has enabled the widespread availability of mild, multifunctional surfactants that combine conditioning, emulsifying, and antistatic properties. Their discovery reflects the broader trend in surfactant chemistry to design molecules that are effective, safe for human use, and environmentally considerate. Over decades, these compounds have become standard ingredients in personal care, textile, and industrial formulations, demonstrating the practical value of combining natural fatty acid feedstocks with quaternary ammonium chemistry.