Written by Norman Lowe, April 2026
In surfactant chemistry, we discuss four broad types based on their ionic charge. The first three are: “anionics,” which provide a negative charge in solution; “cationics,” which provide a positive charge in solution; and “non-ionics,” which do not ionize in solution and thus carry no charge. The fourth type is the “amphoterics,” which possess both a negative and positive charge, for example:
R.N⁺(R²)2.COO־
This example features a quaternary nitrogen group (N⁺R₄) with a positive charge and an acyl group (COO־) with a negative charge within the same molecule. This is balanced at neutral pH and is known as the “zwitterionic form.”
Key Properties of Amphoteric Surfactants
Common properties of amphoterics include:
- Compatibility with anionic, cationic, and nonionic surfactants
- Stable across the entire pH range, typically very mild to the skin, and stable in high levels of electrolytes
- Depending on the alkyl chain length, they can be high-foaming or low-foaming and serve as excellent wetting agents
This versatility makes them highly useful across numerous applications.
Common Types and Industrial Applications
Alkyl and Alkyl Amidopropyl Betaines
These are the reaction products of a Fatty Tertiary Amine or Alkyl Amidopropyl Ternary Amine with an Acyl Chloride, resulting in:
R.N⁺(CH3)2CH2C00־ Alkyl Betaine
Or : R.C(O)NH(CH2)3N⁺(CH3)2.CH2C00־ Alkyl Amidopropyl Betaine
These are commodity surfactants used in detergent and cosmetic systems as foam stabilizers and are primarily high foamers. For more in-depth information on this important group, please ask to see our related article on Alkyl and Alkyl Amidopropyl Betaines.
HARKE UK & Ireland offers an extensive range of Alkyl and Alkyl Amido Betaines from both Verdant and Syensqo. Please contact us for data on the ranges available under the trade names Mackam® (Verdant) and Mirataine® (Syensqo). These include high-active grades, ultra-low salt grades, oral product grades, mass-balanced and coconut-derived options, and powder grades.
Alkyl and Alkyl Amido Sultaines
These surfactants are often referred to as “Sulpho Betaines / Sulfobetaines,” as they are the sulfate equivalents of Alkyl and Alkyl Amido Betaines. In these molecules, the carboxyl group is replaced with a sulfate group, for example:
R.N⁺(CH2)2.CH2CH(OH)CH2.SO3־..Na⁺ Fatty Alky Hydroxy Sultaine
R.C(O)NH(CH2)3N⁺(CH3)2CH2CH(OH)CH2SO3־ Fatty Amidopropyl Hydroxy Sultaine
Sultaines are used in high-foaming applications such as shampoos, body washes, liquid hand soaps, and hand dishwashing liquids. Industrially, they are used in traffic film removers (TFRs) and high-foaming wash systems. They are particularly noted for producing very stable “sticky foams,” which are used in pressure washing high-sided vehicles and large industrial ovens. Generally, sultaines are higher in activity than betaines and remain stable under more extreme electrolyte and alkalinity conditions.
Main Products in Our Range:
- Mackam® CBS 50G Cocamidopropyl Hydroxy Sultaine (HARKE UK & Ireland/Verdant)
- Mackam® LSB 50 Laurylamidpropyl Hydroxy Sultaine (HARKE UK & Ireland/Verdant)
- Mackam® LHS-E Lauryl Hydroxy Sultaine (HARKE UK & Ireland/Verdant)
- Mirataine® CBS -UP Cocamidopropyl Hydroxy Sultaine (HARKE UK & Ireland/Syensqo)
Alkyl Iminodipropionates
R.N[(CH2)2.CO]2
These are the reaction products of fatty primary amines and Acrylic Acid or Sodium Acrylate. Having two carboxylic groups, they can exist in acid, monosodium, or disodium forms depending on the pH. At neutral pH, the nitrogen is not protonated, so the net charge is zero. In acidic conditions, the nitrogen is protonated, giving a charge of +1; in alkaline conditions, the charge is -1. They remain stable across the entire pH range.
Mackam® OIP-40, OIP 50 and OIP-HA (Verdant) (2 Ethyl Hexyl Iminodipropionates)
These products are based on 2-Ethylhexylamine (Iso-Octylamine). They are salt-free, very low-foaming, and act as highly efficient “hydrotropes,” primarily used to solubilize non-ionic surfactants in high-caustic and high-electrolyte systems. Consequently, they find use in hard surface cleaners and traffic film removers. They also act as sludge dispersants in closed systems and CIP cleaners and can reduce the viscosity of high-active detergent systems.
Mackam® DP122, Mackam® H2C-HA, and Mackam® 168L (Verdant)
These are Coco- Or Lauriminodipropionates based on C12-14 alkyl amines. They are salt-free, high-foaming surfactants that retain hydrotrope properties and act as good wetting agents. They are used in high-foaming, high-caustic, and high-electrolyte systems, such as traffic film removers, and are stable across the entire pH range.
Imidazoline-Based Amphoterics
These are the reaction products of Alkyl Imidazolines with either Chloroacetic Acid or Acrylic Acid. Upon neutralisation with Sodium Hydroxide, they yield Sodium Alkyl “Ampho” Acetates (or Disodium Alkyl “Ampho” Diacetates) or Disodium Alkyl “Ampho” Dipropionates. The Alkyl group varies based on required properties, typically C8 (Capryl), Coco, Palm kernel (C8-18), or Lauryl (C12-rich).
Cocoamphoacetates and Diacetates are high-foaming and very mild, making them ideal for baby shampoos, frequent-wash shampoos, hand dishwashing liquids, and high-foaming alkaline TFRs. The short-chain (C8) Capryl variant is very low-foaming and an excellent wetting agent.
Amphodipropionates are largely used in non-cosmetic applications. Short-chain products are very low-foaming, stable in high-caustic systems, and serve as excellent hydrotropes.
Amphoacetates and Diacetates:
- Mackam® Ultra C32 MB, Ultra L32 MB, Mackam® C2M conc NP MB, Mackam® CY75 (Verdant, short chain Capryl (C8) Amphodiacetate)
- Miranol® Ultra L28 ULS MB (Syensqo, ultra low salt grade)
C32 and L32 are based on Coconut oil or Palm kernel oil, the L32 being C12 lauryl-rich. The palm-based ingredients are mass balanced (MB).
Amphodipropionates:
Mackam® 2CSF is a Disodium Cocoamphodipropionate, a high-foaming, salt-free amphoteric.
We offer a blended product, Mackam® JEM, which combines a short-chain Amphoacetate and a short-chain Iminodipropionate. This results in a synergistic product that is very low-foaming with excellent wetting properties, suitable for high-caustic and high-electrolyte cleaning systems such as bottle washing, beer line cleaning, and glass cleaning.
This document provides an overview of the primary amphoteric products on the market and the main products that HARKE UK & Ireland can supply. The technical department at HARKE UK & Ireland has a deep understanding of this chemistry and is adept at formulating products across all these application areas. For further information, please get in touch.
