Full blown green metrics

Green chemistry is one of the most influential concepts widely adopted by chemical industries to achieve sustainability. It has led to our understanding of sustainable ways to improve chemical processes using a standard measure called green metrics. Over the last two decades, studies on various metrics and their correlation were formulated to evaluate existing chemical processes. Yet, chemists and engineers encounter practical difficulties to achieve an entire green and a sustainable chemical process. Thus it is a challenge to measure and deploy every chemical process right from the laboratory scale to pilot plant. Green metrics allow the chemists to quantitatively understand energy, materials and cost-efficiencies that provide strategic planning called “green-by-design”. These metrics make the chemists aware of redesigning their chemical methods and rank the “greenness” of chemical reactions. Currently, green metrics lack reliability and universal applicability to most chemical processes due to their complex framework. Hence, there is a need to improve green metrics for assessing the chemical process for their greener quotient and sustainability. The present chapter describes the different green metrics with industrial examples from synthetic chemistry. Further, we have described the current status on synthetic chemistry-based metrics, green analytical chemistry, bio-based solvents, miniaturization of instruments, and sustainability metrics. Finally, we conclude by asking tough questions on green chemistry and providing a broader view to look at their principles and metric-based equations.