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Formulated products used in hydraulic fracturing are designed to address specific subsurface challenges during oil and gas well completion and are intended for the treatment of a myriad of issues i...

Summary Although the concepts underpinning green chemistry have evolved over the past 30 years, the practice of green chemistry must move beyond the environmental and human health-related roots of green chemistry towards a more systems-based, life cycle-informed, and interdisciplinary practice of chemistry. To make a transition from green to sustainable chemistry, one must learn to think at a systems level; otherwise green chemistry-inspired solutions are unlikely to be sustainable. This perspective provides a brief description of why the current situation needs to change and is followed by how life cycle thinking helps chemists avoid significant systems-level impacts. The transition from batch to continuous flow processing and novel approaches to isolation and purification provide a case for interdisciplinary collaboration. Finally, an example of end-of-useful-life considerations makes the case that systems and life cycle thinking from an interdisciplinary perspective needs to inform the design of new chemical entities and their associated processes., Graphical abstract, Highlights • Green and sustainable chemistry must include a systems and life cycle perspective • Green and sustainable chemistry requires extensive interdisciplinary collaboration • Catalysis, purification and isolation, and batch to flow processing are discussed, Chemistry; Organic chemistry; Green chemistry; Green engineering

To remain relevant, chemists need to be able to understand their work in terms of systems. Since systems thinking is a framework to understand and manage systems, the introduction of systems thinki...

David J.C. Constable is the science director of the American Chemical Society's Green Chemistry Institute. In this role, he works to catalyze and enable the implementation of sustainable and green chemistry and engineering throughout the global chemistry enterprise.

The solvent selection methodology developed earlier by Gani et al. [Gani, R., Jimenez-Gonzalez, C., & Constable, D. J. C. (2005). Method for selection of solvents for promotion of organic reactions. Computers and Chemical Engineering , 29 , 1661–1676] has been extended to handle multi-step reaction systems as well as solvent substitution for specific reaction steps for existing processing systems. The problems were formulated based on the methodology guidelines, and solved using ICAS software tool [ICAS Documentation. (2003). Internal report . CAPEC, Department of Chemical Engineering, Technical University of Denmark]. Highly promising results were obtained, either in accordance with results previously published in the literature, or with industrial process data. This shows that the methodology has potential for application to complex reaction schemes as well as on the problems of solvent replacement.

A Green Technology Comparison framework incorporating a life cycle approach and sustainability metrics has been used to compare the performance, and the environment, health, safety, and life cycle impacts of two synthetic methods used to produce 7-aminocephalosporic acid (7-ACA). The routes under study were a chemical synthetic process and a two-enzyme catalyzed process, both starting from the potassium salt of cephalosporin C. Cradle-to-gate life cycle impact estimations were performed using the Fast Life Cycle Assessment of Synthetic Chemistry (FLASC™) tool and following modular gate-to-gate methodology. The results compare the synthetic efficiency, environment, health, safety, and life cycle metrics for a mature chemical process and a more recent but less developed enzymatic process for making 7-ACA. The chemical process has a higher yield, but a significantly lower reaction mass efficiency and half the mass productivity of the enzymatic process. The chemical process uses more hazardous materi...

The solvent selection methodology developed earlier by Gani et al. (Comp. Chem. Eng., 2005) has been extended to handle multi-step reaction systems. The solvent selection problem was formulated based on the methodology guidelines, and solved using ICAS software tool. A list with solvent candidates is generated so that it can be further investigated experimentally. Comments and clarifications from chemists have been incorporated into the problem formulations to clarify the role of the solvents in the chemistry and potential reactivity issues. Highly promising results were obtained, in accordance with Industrial process data.

A method to select appropriate green solvents for the promotion of a class of organic reactions has been developed. The method combines knowledge from industrial practice and physical insights with computer-aided property estimation tools for selection/design of solvents. In particular, it employs estimates of thermodynamic properties to generate a knowledge base of reaction, solvent and environment related properties that directly or indirectly influence the rate and/or conversion of a given reaction. Solvents are selected using a rules-based procedure where the estimated reaction-solvent properties and the solvent-environmental properties guide the decision making process. The current method is applicable only to organic reactions occurring in the liquid phase. Another gas or solid phase, which may or may not be at equilibrium with the reacting liquid phase, may also be present. The objective of this method is to produce, for a given reaction, a short list of chemicals that could be considered as potential solvents, to evaluate their performance in the reacting system, and, based on this, to rank them according to a scoring system. Several examples of application are given to illustrate the main features and steps of the method.

A considerable amount has been written about the use of metrics to drive business, government and communities towards more sustainable practices. A number of metrics have also been proposed over the past 5–10 years to make chemists aware of the need to change the methods used for chemical syntheses and chemical processes. This paper explores several metrics commonly used by chemists and compares and contrasts these metrics with a new metric known as reaction mass efficiency. The paper also uses an economic analysis of four commercial pharmaceutical processes to understand the relationship between metrics and the most important cost drivers in these processes.

A set of metrics has been developed which enables a simple assessment to be made of batch processes in terms of waste, energy usage, and chemistry efficiency. It is intended to raise awareness of green chemistry by providing a tool to assist chemists in monitoring progress in the reduction of environmental impact as they design new routes and modify processes.