Technological breakthroughs

As the world seeks to reduce its dependence on fossil fuels and curb pollution, a group of environmentally friendly surfactants is attracting increasing attention. These are alkyl polyglycosides (APGs)—compounds made from sugar and naturally derived fatty alcohols.

What Are APGs and Why Are They “Green”?

APGs belong to the group of nonionic surfactants. They are synthesized from renewable raw materials such as glucose, derived from corn starch, potatoes or wood, and fatty alcohols, which are commonly sourced from coconut or palm oil. Unlike many conventional petroleum-based surfactants, APGs are readily biodegradable, relatively mild to the skin and eyes, produce fine and stable foam, and offer strong cleaning performance.

Structurally, each APG molecule consists of two parts: a hydrophilic “head” made up of sugar units and a hydrophobic “tail” consisting of a hydrocarbon chain. When the carbon chain contains between C8 and C14, the products generally deliver the best performance, including good water solubility, strong surface-tension reduction, stable emulsification and greater safety compared with many conventional cleaning agents.

Toxicological studies indicate that APGs have very low acute toxicity and do not generally cause allergic reactions or genetic mutations at concentrations normally used. They also biodegrade rapidly under both aerobic and anaerobic conditions, ultimately breaking down into carbon dioxide and water—an advantage over many other synthetic surfactants.

How Are APGs Produced?

The most common production method is glycosidation, in which sugar reacts with fatty alcohol under acid catalysis to form glycosidic bonds. Two main approaches are used: a one-step direct process and a two-step process involving a short-chain alcohol intermediate.

Catalyst technology has evolved over time. Early processes relied on strong inorganic acids such as sulfuric acid. These have increasingly been replaced by organic acids such as p-toluenesulfonic acid and dodecylbenzenesulfonic acid, which help reduce equipment corrosion and produce lighter-colored products. Today, researchers are focusing on solid catalysts and ionic liquids, which can be easier to separate and recycle and may offer environmental advantages.

Other approaches include enzymatic catalysis, phase-transfer catalysis and more complex techniques such as Koenigs–Knorr and trichloroacetimidate methods. Enzymes offer mild reaction conditions and high selectivity, but their relatively high cost and slow reaction rates have limited their widespread industrial adoption.

New technologies, including microwave-assisted processing and high-gravity reactors, are also being investigated to accelerate reactions, lower operating temperatures and reduce sugar degradation or self-polymerization—problems that can cause products to darken and make purification more difficult.

Practical Applications

In cosmetics and personal care products, APGs are used in facial cleansers, shampoos, moisturizing creams, liquid soaps and other formulations because of their mildness and ability to form stable emulsions. They can help reduce irritation and are therefore suitable for sensitive-skin products and formulations designed for children.

In household detergents and cleaning products, APGs offer effective grease removal, fine foam, good hard-water tolerance and rapid biodegradability, helping to reduce the environmental impact of cleaning products on water systems. They are also used in metal cleaners and various specialized industrial formulations.

In the oil and gas industry, APGs can reduce interfacial tension between oil and rock and alter the wettability of reservoirs, thereby helping improve oil recovery. They offer relatively good thermal and salt tolerance while posing fewer environmental concerns than many conventional chemicals.
In pharmaceuticals and agriculture, APGs can serve as carriers or formulation aids, improving the solubility of active ingredients, enhancing their penetration through the skin or plant surfaces, and increasing the stability of nanoemulsion systems.

Remaining Challenges

Despite having already been commercialized, large-scale APG production still faces several challenges. Long-chain fatty alcohols and sugars have limited compatibility, which can slow the reaction and require an excess of alcohol. After the reaction, the excess alcohol must be removed through dealcoholization, while decolorization is also required. Both processes consume energy and can damage the product if the temperature is not carefully controlled.

Manufacturers are increasingly adopting multistage evaporation systems, such as combinations of falling-film evaporators with wiped-film or short-path evaporators, to reduce temperature and thermal exposure. For decolorization, hydrogen peroxide is widely used together with high-speed mixing equipment designed to improve efficiency while minimizing foam formation.

Outlook

The global APG market is expected to grow strongly over the coming decade. Key development directions include the use of recyclable catalysts, optimization of reaction and purification processes, and expansion into premium cosmetics, environmentally friendly cleaning products and greener enhanced oil recovery technologies.

APGs are not a single “magic bullet” for sustainable chemistry. However, they demonstrate how chemical products can combine effective performance with greater consideration for human health and the environment. As production technologies continue to improve, the shampoos, dishwashing liquids and industrial cleaning formulations used every day may become increasingly sustainable—and sugar and plant-derived oils are likely to play an important role in that transition.

Reference
Zhang, B., Yang, C., Liao, S., Lai, X., Zhang, Y., Chen, B., & Xiong, W. (2025). Progress on the synthesis and applications of the green non-ionic surfactant alkyl polyglycosides. RSC Advances, 15(55), 47333–47359.