Plant-Derived and Natural Surfactants

Posted On: March 10, 2020

Paradigm shifts in market segments are commonly governed by societal reactions to external influences from science or engineering. A global push to reduce an economy’s energy-dependence on fossil fuels is a prime example of how scientific evidence can change the mindset of society.

Oxiteno and the entire surfactant industry are not immune to these societal pressures. The surfactant (and chemical industry as a whole) have been compelled to use more natural, renewable, and sustainable methods to prepare their products, which is why Oxiteno has taken the appropriate measures to become one of the global leaders in the sustainable surfactants industry. To understand Oxiteno’s line of naturally-sourced surfactants, a quick overview of surfactants and their ‘naturalness’ is necessary.

Surfactants contain both a water-loving (hydrophilic) and a water-fearing (hydrophobic) components. This unique structure is why surfactants are significant players in a variety of industrial and commercial applications, including agrochemicals, home and personal care, industrial and institutional (I&I), paints/coatings, and oil and gas surfactants.

The home, beauty, and personal care markets use surfactants in many products that are used by consumers daily. These products include but are not limited to shampoos (to aid in emulsification), perfumes (as solubilizing agents), cosmetics (to help disperse pigments in make-up), and detergents (to assist in cleaning).

However, the new trend in today’s world is to ensure that these products are not detrimental to both our personal health, as well as, the health of the environment. For this reason, many consumers are pushing to use more natural sourced products, as the general idea is that the more “natural” a product is, the “healthier” is it is for consumers and the environment.

What Are Natural Surfactants?

So, what is a natural surfactant? There are many definitions used throughout the various commercial sectors to market “natural products.” In speaking of terms of 100% natural, one definition could be, “any ingredient isolated from a plant that acts as a surfactant.”

As you can imagine, there are very few truly natural surfactants used today. One of the more common truly natural surfactants used is saponin. However, these surfactants are expensive to isolate from plants in high yields, not to mention that they are nearly as effective at cleaning as the commercially available ethoxylated surfactants.

Cosmetics, Organic, and Natural Standards (COSMOS)

Due to the limited availability of truly natural surfactants, international standards, like the Cosmetics Organic and Natural Standards (COSMOS), have developed a more encompassing definition for natural products:

“natural products are those that mainly contain ingredients from natural origin:  water, minerals, and ingredients of mineral origin, physically processed agro-ingredients, chemically processed agro ingredients (and parts thereof) derived wholly from the above. This list excludes petrochemical moieties, preservatives, and denaturing agents of petrochemical origin”.1

What this definition is stating, is that, if any part of a surfactant is sourced from a natural origin, then it can be considered a natural product.

When using the COSMOS standard, ethoxylated plant-derived surfactants (i.e. coconut-derived surfactants) can be used to develop products that meet the criteria for COSMOS natural certification because a portion of the raw materials used to synthesize these types of surfactants is sourced from renewable, plant-based materials.

ISO 16128

Other organizations, such as the International Standardization Organization (ISO), a segment of the World Trade Organization (WTO), take the definition of naturally derived a step further. According to the ISO 16128, ethoxylated and sulfonated products are considered non-natural ingredients. However, this does not mean that if your product contains any sulfonated or ethoxylated product, it would no longer be considered of natural origin.

One of the main objectives of the ISO 16128 is to define a harmonized criterion to calculate the natural origin index and the natural origin content of a product. Therefore, you can have a product that contains up to 9% ethoxylated and sulfonated ingredients and have a natural origin content of 91%.

USDA

Another definition, supplied by the USDA, refers to the bio-content of particular products. In their definition of “Biobased products are derived from plants and other renewable agricultural, marine, and forestry materials and provide an alternative to conventional petroleum-derived products”.2  While the word natural does not necessarily enter the USDA’s definition, the term renewable does imply being sourced from a natural origin. The amount (or percentage) of a compound that is sourced from these renewable origins can be theoretically calculated and experimentally verified.

Depending on which definition you use, plant-based materials do not necessarily mean “natural” as many plant-based materials undergo secondary reactions resulting in final products added to consumer goods. Soaps are the most historic example of this, as fats (triglycerides) were saponified to produce the appropriate potassium carboxylate (i.e. soap).

In a similar manner, coconut oil can be isolated into lauryl alcohol using chemical and physical means. Unlike soap, the resulting lauryl alcohol is then further chemically modified (i.e. ethoxylated) yielding a nonionic plant-based surfactant. These coconut-derived surfactants can then be further reacted to produce the well-known sodium lauryl ether sulfates (SLES) that are in many household cleaning supplies and personal care products. So, while the final product may have a significant amount of chemistry performed to it, most of the product can still be sourced from a natural and renewable material.

Benefits of Natural and Plant-derived Surfactants

There are many benefits to using plant-based, raw materials. Because lauryl alcohol can be directly sourced from plants, the environmental impact from their synthesis from fossil fuels is greatly diminished, affording a method to continuously produce these plant-derived surfactants for our future.

Another significant advantage is the reduction in greenhouse gases. Traditionally, propylene glycol (the first cousin of a surfactant) is derived from petroleum, a non-renewable source. Over the past few years, scientists figured out how to convert renewable plant-based glycerin to propylene glycol using a catalytic process known as hydrogenolysis. Using hydrogenolysis reduces greenhouse gases by 61% compared to the traditional method of producing propylene glycol from petroleum.3

The Push for Biodegradable Surfactants

Knowing the sourcing information of raw materials allows us to answer questions like ‘where did it come from’ and ‘how much of this product is natural,’ which are important questions relating to a product’s impact on the environment. Nevertheless, a remaining question of ‘what happens to the product once it is used’ remains.

Recently, there has been a big push for not only using natural- or plant-based surfactants in consumer goods but also to use more eco-friendly and biodegradable surfactants as well. Balson and Felix described biodegradation as the destruction of a chemical by the metabolic activity of microorganisms such as bacteria, fungi, and algae.4  Knowing if a product can be broken down into innocuous components is an extremely poignant aspect for all chemicals, but especially for surfactants, as these types of molecules are ageNTS that are ACTive on all types of SURFaces…hence the name SURFACTANTS.

Because one portion of a surfactant is hydrophilic and the other hydrophobic, these molecules can commonly be dispersed in aqueous systems, allowing for rapid microbial uptake. The molecular architecture of surfactants, which can be governed by the sourcing of their raw materials (for instance plant-based), can dictate how rapidly these products are consumed in the environment and certain generalizations can be made regarding the biodegradation of surfactants. For instance, linear alcohol ethoxylates are more biodegradable than their branched counterparts. Linear alcohol ethoxylates are considered readily biodegradable as observed by >80% degradation in 28 days for linear, and 40% for some branched alcohol ethoxylates. 5  Generally speaking, linear alcohols are sourced from renewable materials, as branched alcohols are not nearly as common in the environment.

Examples of Natural Surfactants from Oxiteno

Oxiteno has recognized both general trends of renewable sourcing and biodegradation in the surfactant industry. We have made strides to not only increase our production of plant-based surfactants that are made from renewable sources but to improve their effectiveness as surfactants, making these bio-based surfactants a more appealing option for the consumer.

Additionally, Oxiteno has recognized the need to offer a wider selection of biodegradable surfactants and has moved away from offering products that are known to bio-accumulate. For more information regarding the bio-properties of our surfactants, please feel free to contact Oxiteno online.

Oxiteno offers a full line of plant-derived surfactants including cetearyl-, cetyl-, cetyl oleyl- lauryl-, stearyl- alcohol ethoxylates (ALKONAT®), castor oil ethoxylates (ALKEST CSO®), and lauramine oxides (NEOMINOX®), all of which are derived from either renewable palm or coconut oil. Keep in mind, plant-derived surfactants are not guaranteed to work as well as synthetic, or petrochemically derived surfactants. In fact, there are many common uses for plant-derived surfactants.

Many of the alcohol ethoxylates mentioned above are used in a wide range of industrial and household cleaning products. Lauryl alcohol ethoxylates, which are derived from palm oil, are common natural surfactants for shampoo and shower gel because they act as foaming agents. Lauryl alcohol ethoxylates also have excellent wetting properties making them ideal for use in industrial and household cleaning products. These are great natural surfactants for laundry detergents and cleaners where the ability of such products to clean heavily depends on its ability to wet the surface of textiles and hard-surfaces.

Oxiteno offers a full line of lauryl alcohol ethoxylates (ALKONAT® L-series). Castor oil ethoxylates find many uses in a variety of industries because this class of compounds is a versatile emulsifier, solubilizer, emollient, dispersant, and lubricant. Due to the many potential areas of applications, Oxiteno’s ALKEST® CSO and SURFOM® R series are used in various applications by agricultural, oil & gas, textile, cosmetic and metal-working industries. Lauramine oxides and cocamidopropyl betaines have gained much traction in the home & personal care market, specifically in hair-care products, body washes, and hand soaps, due to their mild nature (compared to SLES) and their excellent foaming properties.

Visit our site for more information of Oxiteno’s line of plant-derived surfactants, and our capabilities as one of the leading U.S. surfactant manufacturers.

 

  1. “COSMOS-standard Cosmetics organic and natural standard Version 3.0 – 21st October 2013” (PDF). COSMOS-standard AISBL. Revised January 2019.
  2. https://www.biopreferred.gov/BioPreferred/faces/pages/BiobasedProducts.xhtml
  3. “Kicking the Oil Habit: Making Propylene Glycol from Plants.”  gov- www.energy.gov/technologytransitions/kicking-oil-habit-making-propylene-glycol-plants
  4. Balson, M.S.B. Felix, The biodegradability of non-ionic surfactants, in: D.R. Karsa, M.R. Porter (Eds.), Biodegradability of Surfactants, Blackie Academic and Professional, 1995, pp. 204–230.
  5. L Kravetz, J.P Salanitro, P.B Dorn, K.F Guin, Influence of hydrophobe type and extent of branching on environmental response factors of non-ionic surfactants, J. Am. Oil Chem. Soc., 68 (1991), p. 610