Green Surfactants: Alkyl Polyglucosides

Alkyl polyglucosides (APG) are leading green surfactants offering sustainable solutions for various industries. As Book Chem, we’re excited to provide insights into alkyl polyglucosides.

Development History of Alkyl Polyglucosides

Alkyl polyglucosides (APG) have a history of over 100 years from research to the present. Foreign research on APG started early, but industrialization was implemented later. In 1893, Germany’s Fisher first reported the synthesis technology of alkyl polyglucosides, but it was not until the 1980s, due to concerns about the environment and petroleum resources, combined with the excellent characteristics of alkyl polyglucosides themselves, that greater attention was paid to their industrialized research.

France’s Seppic company first achieved industrial production of APG in 1978, with a capacity of 1,000 t/a, and built a 10,000 t/a production facility in 1992. Germany’s Henkel company acquired the US’s Horizon Chemical company in 1988 and purchased its 4,000 t/a pilot plant, expanding it to 25,000 t/a, which was built and put into operation in Cincinnati, USA, in 1992, achieving large-scale industrial production of APG. The company’s another 25,000 t/a production facility was constructed in Düsseldorf, Germany, in November 1993 and commissioned in September 1995.

In China, research on alkyl polyglucoside synthesis began in the 1980s, led by the China Research Institute of Daily Chemical Industry and Dalian University of Technology, conducting research on long-chain (C8 and above) APG synthesis. The China Daily Chemical Institute used glucose and fatty alcohols to produce APG products via a two-step method, applying for the first patent in China (CN1077397A) in 1992. In 1994, 1,000 t/a pilot plants were built in Guangdong and Hubei, respectively, with product quality indicators meeting the requirements of the national “Eighth Five-Year Plan” key project, filling the gap in domestic APG production. During the “Ninth Five-Year Plan,” the China Daily Chemical Institute successfully developed a one-step process for APG and put it into production.

Overview of Alkyl Polyglucosides

Alkyl polyglucosides (APG) are new, efficient, non-toxic, biodegradable non-ionic surfactants with excellent surface activity. After compounding, they can form the best surfactants currently available. Alkyl polyglucosides have outstanding performance, low surface tension, strong foaming power, stable foam, good wettability, excellent compatibility, low irritation to the human body, extremely low toxicity, and rapid biodegradation. It is currently the only variety in the world that can be called non-toxic grade. Therefore, alkyl polyglucosides are renowned as “world-class” surfactants due to their superior performance.

Properties of Alkyl Polyglucosides

Physical Properties and Solubility

APG products are mostly made into 50%~70% aqueous solutions. Pure APG is a white powder, but actual products are creamy, light yellow to amber in color. Its physical properties are closely related to the alkyl carbon chain, sugar type, and degree of polymerization used in synthesis. The melting point increases with the growth of the carbon chain in the product molecule, and some high alkyl polyglucosides begin to decompose before melting, indicating that alkyl polyglucosides are prone to decomposition and discoloration when heated. APG is a hygroscopic solid, generally soluble in water, more soluble in common organic solvents, and exhibits excellent compatibility, stability, and surface activity in acidic and alkaline solutions, especially in active solvents with high inorganic components.

Biodegradability

Biodegradation by microorganisms is an important elimination mechanism to prevent surfactants from accumulating to dangerous concentrations in the environment. Alkyl polyglucosides are synthesized from starch and its hydrolysates with fatty alcohols. Alkyl polyglucosides can be completely biodegraded in nature without forming metabolites that are difficult to biodegrade, thus avoiding new pollution to the environment.

Detergency

The detergency of surfactants varies with ion type, washing conditions, and dirt type. Sebum dirt on polyester/cotton is sensitive to non-ionic detergents. The detergency effect of APG is equivalent to that of sodium fatty alcohol polyoxyethylene ether sulfate (AES) and superior to linear alkylbenzene sulfonate (LAS), AS, and SAS.

Surface Activity

The fatty alcohol alkyl carbon chain provides a non-polar lipophilic group, so alkyl polyglucosides with alkyl chain lengths greater than 8 carbons typically have surface activity and critical micelle concentration (CMC). As the alkyl carbon chain grows, its surface tension significantly decreases, and the CMC value also decreases, indicating a significant increase in activity. According to literature reports, experiments comparing APG with fatty alcohol polyoxyethylene ether (AEO) and LAS concluded that dodecyl fatty alcohol alkyl polyglucosides have good surface activity.

Synthesis Processes of Alkyl Polyglucosides

The synthesis processes of alkyl polyglucosides are mainly divided into two types: one-step method (direct synthesis) and two-step method (transglycosylation).

One-Step Method (Direct Method)

• Advantages: Low equipment requirements, mild reaction conditions, easy control of production process, shorter reaction time.
• Disadvantages: Increased reaction difficulty, must use a sufficient excess of fatty alcohol to control sugar self-polymerization, reduce the generation rate of alkyl glucosides.

Two-Step Method (Transglycosylation Method)

• Advantages: Better solves the compatibility issue between raw materials, synthesis is easier to achieve, shorter reaction time; excess fatty alcohol is easy to evaporate.
• Disadvantages: More complex process, higher production costs, and products often contain butyl glucosides that are not easy to remove, resulting in poorer APG product quality, which to some extent affects product performance.

In summary, the one-step method has yield issues, while the two-step method has quality and cost issues.

Supply and Demand Situation of Alkyl Polyglucosides

The consumption demand for liquid detergents is constantly increasing. Since detergents containing APG improve product quality, with the increase in consumer income levels, the consumption of high-end detergents will continue to increase, thereby driving APG consumption in the Chinese market.

The grade of care products is constantly upgrading, and the improvement in product grade promotes APG consumption. At the same time, care products for infants and young children will tend to select milder surfactants, providing new opportunities for the downstream market of APG.

In the agrochemical field, APG is used to replace alkylphenols, branched benzenes in pesticides. These surfactants degrade slowly, and the degraded alkylphenols and fatty amines are more toxic, posing potential hazards to the environment. APG has low toxicity, easy biodegradation, does not pollute soil, and has no toxicity to crops, making it a good substitute for other alkylphenols and branched benzene surfactants.

According to relevant institutions’ predictions, the demand for APG will continue to increase in the coming years, expected to maintain an annual growth rate of over 10%.

For premium alkyl polyglucosides and other green surfactants, explore Book Chem’s range at Alkyl Polyglucoside Products. We’re committed to advancing alkyl polyglucosides as top bio-based surfactants for sustainable innovation.

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