Successful substitution is about more than replacing X with Y
By Lauren Zarama, CEO, InKemia Green Chemicals, Inc.
As a company that develops green chemistry technologies, we are often asked: “What do you have that is a good replacement for [insert any chemical of concern]?”
While we are very glad to receive the question, the answer is not always straightforward.
Why? Unless there is evidence of prior successful replacements in identical or similar processes or products, the solution will depend on the specific industrial application and the sustainability goal that must be achieved.
If your sustainability goal is to find a biobased version of an existing oil-derived chemical, the substitution might not be difficult from the technical perspective, since the drop-in solution will work perfectly due to the chemical property match.
If, however, your sustainability goal is to reduce the hazardous nature of a functional ingredient in a consumer product, eliminate the risk of explosion or some other danger, the molecular structure change needed will impact the final product or process – often negatively. It means that substituting undesired chemicals with safer alternatives is not trivial and requires careful planning, adequate chemical tools and sound scientific methodologies.
When seeking alternative chemicals to integrate into a product or process, many factors must be considered that go beyond looking for a property match.
For example, will the new chemical perform the same function as the chemical to be replaced? Is the new chemical compatible with the rest of the ingredients in the formulation? Is it compatible with the equipment you are using? Are there any conflicting constraints that the new chemical generates based on synergistic or antagonistic effects? Is the alternative more expensive? Does it have the right regulatory approvals?
“Substituting undesired chemicals with safer alternatives is not trivial and requires careful planning”
While some of the above factors may be correlated to the chemical structure, there are many properties relevant to the product or process performance that cannot be predicted with sufficient accuracy.
As a result, R&D teams have no other option than to experiment with the substitution. One additional problem that R&D teams face is the existence of rough fitness landscapes.
For example, a successful substitution of a chemical in a specific product, say a makeup formula, does not necessarily mean you can replace that same chemical in a body wash formulation. The notion of universal replacements is often misleading and this applies no matter the industry.
The key to a successful replacement is the ability to find the right compromise between a large number of essential functional properties. To achieve this, you need a sufficiently large and diverse set of chemicals that are potential candidates for the substitution.
“The notion of universal replacements is often misleading and this applies no matter the industry”
There is in fact a mathematical relationship between the probability of finding optimal solutions and the size and diversity of the chemical libraries from which the solution is sought. Therefore, increasing the repository of green chemicals is a major goal at InKemia.
We also explore new chemical spaces and expand the range of available green chemicals by designing and developing new chemicals.
But we believe our greatest value is found in our ability to innovate through a diverse business model and by working with any part of the value chain. Our business model moves along the spectrum from contract research to joint development and finally to internal R&D projects.
Our customers range from raw material suppliers to chemical manufacturers to retailers. This flexibility allows us to develop positive relationships with other chemical suppliers and companies that produce green chemical technologies because we can connect their materials with new applications and customers.
Our hope is that by sharing details with you about how InKemia approaches the substitution of chemicals of concern that it can help in planning your own efforts related to optimizing the chemicals in your products or processes.