Our approach to evaluating greener chemicals is based on the 12 Principles of Green Chemistry. We recognize that these principles distill into three major categories: improving resource use, more efficient use of energy, and minimizing human and environmental hazards. At present, we are not incorporating lifecycle impacts of raw materials (ie raw material extraction, pre-processing and manufacture), but we are considering hazards of and the efficient use of such materials. Our approach intends to share with customers our view on product performance aligned with each Principle, as well as within the three larger categories. Below we present each Principle and our approach to quantify a green score for the Principle.
Principle 1 drives an overall approach to resource efficiency by considering the relationship between all input materials to a process (reactants and auxiliaries) and the desired product produced. Other Principles, such as 2, 5, 8, 9 etc. drive specific elements or approaches to resource efficiency. We are exploring approaches that allow us to variously weight more and less desirable waste management tactics.
While Principle 1 focuses on all input materials, we have crafted our approach for Principle 2 to focus on finding opportunities to reduce the amount of reactant used to produce the desired product.
In Principles 3, 4, and 5 we evaluate both the amount and toxicity of the various components of chemical synthesis, specifically raw materials, products, and solvents as detailed herein.
Our approach for Principle 3 is to reduce average amount and toxicity of raw materials used per kg of product. We recognize the many forms of toxicity and have aligned our approach to our GHS. By aligning with the GHS, we optimize both the efficiency and global relevance of our data collection process.
In Principle 3 we focus on using less toxic input materials, for Principle 4 we use the same GHS based approach to focus on the toxicity of the produced product. Recognizing that a chemical process may produce multiple products (“coproducts”), we are careful to consider the toxicity of products and co-products when we address this Principle.
We leverage the approach used for Principles 3 and 4, to focus on reducing the amount and toxicity of solvents and other separation agents used per kg of product.
We are developing an estimation of energy impact by considering the amount of time synthesis steps deviate from ambient pressure and temperature.
We prioritize the use of renewable feedstocks when practicable. For this Principle we catalogue at a minimum whether bio-based feedstocks are in use.
We recognize that each derivatization step require additional reagents and can generate waste. Our aspiration for this Principle is to develop a process to catalogue reductions in derivatization waste either directly or by proxy.
Our aspiration for this Principle is to develop a process to catalogue where the use of a catalyst reduces waste either directly or by proxy. Principle 9 serves as a compliment to Principle 2, likely driving improvements in atom economy via the specific route of catalyst use.
We approach Principle 10 with a recognition that we need to account for whether a product is readily biodegradable, as well as the hazards of biodegradation products. We default to GHS environmental hazard criteria for parent and degradation products.
For Principle 11 we are incorporating an approach to recognize the value of process steps that incorporate process analytical chemistry, for example real-time, in-process analysis to detect changes in process temperature or pH for example. We recognize that the sooner deviations from plan are corrected, the less likely a process is to generate additional waste or cause additional hazard.
The significance of principle 12 is to reduce the average physical hazards of raw materials per kg of product. We engage GHS physical hazard criteria across the range of hazard types such as explosivity, flammability, oxidizing capabilities and corrosivity.