Cocamidopropyl Betaine (CAPB) is an amphoteric surfactant primarily derived from fatty acids of coconut oil and dimethylaminopropionic acid.
It is widely used in personal care and cleaning formulations as a foaming agent, cleanser, and conditioning additive.

Chemical Structure

General Formula:
R–CO–NH–(CH₂)₃–N⁺(CH₃)₂–CH₂–COO⁻

Where represents a fatty alkyl chain (mainly C₁₂ and C₁₄, with smaller fractions of C₁₆ and C₁₈).

Cocamidopropyl betaine contains both hydrophilic (betaine group) and hydrophobic (alkyl chain) segments.
It behaves as a cationic surfactant in acidic media and as an anionic surfactant in alkaline conditions, giving it its amphoteric nature.

Typical Physical and Chemical Properties

Property	Specification
Appearance	Clear to pale yellow, viscous liquid
Odor	Mild, characteristic coconut-like odor
Density (25°C)	1.045 – 1.085 g/cm³ (per Sigma-Aldrich)
pH (10% solution)	4.5 – 6.5 (depending on purity and formulation)
Active Matter	28 – 32%
Solubility	Fully soluble in water
Hard Water Stability	Excellent
Chemical Compatibility	Compatible with anionic, cationic, nonionic, and amphoteric surfactants

Applications of Cocamidopropyl Betaine

Personal Care and Cosmetic Products

Mild and baby shampoos
Liquid hand soaps and shower gels
Facial cleansers and gentle laundry detergents

Functional Roles

Foam booster and foam stabilizer
Viscosity enhancer in surfactant blends
Skin and hair conditioner, providing softness and moisture

Advantages

Mild to skin and eyes (per OECD 404 and 405 testing)
Compatible with all major surfactant types
Stable over a wide pH range
Readily biodegradable and environmentally safe (complies with OECD 301)
Sulfate-free (SLS/SLES-free) with low irritation profile

Limitations & Safety Considerations

May cause contact sensitization in rare cases — typically due to trace impurities such as Dimethylaminopropylamine (DMAPA) or amidoamine residues.
Possible nitrosamine formation in the presence of nitrites under certain conditions.
Slightly higher cost compared to conventional synthetic surfactants like SLES.

Safety & Handling Information

Aspect	Guideline
Skin and eye contact	Low irritation potential; rinse with water after prolonged contact
Inhalation	Non-volatile; no vapor hazards under normal conditions
Flash Point	> 100°C
Storage Conditions	Store in tightly sealed containers, in a cool, dry area away from direct sunlight and strong oxidizers
Environmental Stability	Biodegradable and low toxicity to aquatic organisms

Summary

Cocamidopropyl Betaine is a mild, multifunctional amphoteric surfactant valued for its excellent foaming, cleansing, and conditioning properties.
Its biodegradability, low irritation potential, and broad compatibility make it an essential ingredient in modern personal care and household formulations, particularly in sulfate-free systems.