SURFACTANTS purification. What has changed is the level of environmental and regulatory attention surrounding it.
Germany initiated a REACH restriction process concerning the manufacture, placing on the market and use of 1,4-dioxane in surfactants. That intention was withdrawn on 20 August 2025 while German authorities assess new information concerning environmental emission pathways and possible regulatory measures. No restriction arising from that proposal is currently in force. 2
For the Formulation Triangle, however, the important point is not whether a particular limit ultimately appears. SLES did not suddenly stop working. Its detergency did not disappear. Its foam did not disappear. Its ability to create commercially attractive formulations did not disappear.
What changed was how one aspect of its sustainability and stewardship profile was being evaluated. That alone can move a material within the triangle.
Solving one problem can create another
It is technically possible to manufacture SLES with very low residual 1,4-dioxane. Lower residual levels can be achieved through tighter process and purification control.
However, additional control rarely comes for free. More stringent purification can mean additional energy, process time, analytical control and capital requirements. The material may retain the same measured cleaning performance in a defined application while the manufacturing economics change.
This illustrates an important point about sustainable formulation. We often talk about replacing a material as though the problem exists only inside the molecule. In practice, sustainability is also shaped by the infrastructure surrounding that molecule: how it is manufactured, purified, transported and regulated.
A material can therefore move towards or away from one corner of the triangle while remaining chemically almost unchanged. Figure 2 illustrates this movement: SLES performance can remain broadly constant while sustainability and affordability shift around it.
Is AOS the answer?
One chemistry receiving increasing attention as an alternative anionic surfactant is alpha olefin sulfonate( AOS). This offers strong detergency and high foam and is readily biodegradable. Because its manufacture does not require ethoxylation, it avoids the same ethoxylation-derived 1,4-dioxane pathway.
At first sight, that appears to provide a straightforward solution. In practice, substitution is not that simple. AOS behaves differently in formulation, so replacing an established SLES system may require reformulation to reproduce the desired foam, electrolyte response, rheology and sensory profile.
This brings affordability back into the equation. Even where the primary surfactants appear commercially comparable, the finished formulation may not be. More importantly, conventional commercial alpha olefins have historically been produced from petrochemical ethylene.
Moving from an SLES with a largely renewable fatty alcohol carbon contribution to a conventional fossilderived AOS could therefore solve one stewardship issue while moving the formulation in the opposite direction on renewable carbon. That is an uncomfortable but useful example
Figure 2 – How SLES can move within the triangle
NOV / DEC 2026 SPECCHEMONLINE. COM
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