Atom Economy principles

Nowadays, a chemical process for the production of a desired product has to be evaluated considering its conversion, chemical yield and selectivity, but also its atom efficiency, according to the atom economy principle established by Trost in 1991. ... 

Early pioneers in green chemistry included Trost (who developed the atom economy principle) and Sheldon (who developed the E-Factor). These measures were introduced to encourage the use of more sustainable chemistry and to provide some benchmarking data to encourage scientists to aspire to more benign synthesis. 

According to the atom-economy principle included in the 12 principles of Green Chemistry, protocols where all the materials used in the process are incorporated in the end product are highly desirable. In this context, multicomponent reactions, which perform with good atom economy, are interesting reactions. Gold-catalysed multicomponent reactions under solvent-free conditions have been extensively studied. 

A synthetically powerful method, an approach based on cycloaddition chemistry, allows one to assemble the pyridine ring in one step. Not only is this method efficient, atom economy, but also its convergency allows for the preparation for highly substituted systems in which one can, in principle, control all five positions on the pyridine ring. A versatile example of this methodology is the Boger reaction. It has been applied to the synthesis of a very diverse set of targets. 

One of the fundamental and most important principles of Green Chemistry is that of atom economy. This essentially is a measure of how many atoms of reactants end up in the final product and how many end up in byproducts or waste. The percentage atom economy can be calculated as 100 times the relative molecular mass (RMM) of all atoms used to make wanted product divided by the RMM of all reactants. Box 1.2. The real benefit of atom economy is that it can be calculated at the reaction planning stage from a balanced reaction equation. Taking the following theoretical reaction ... 

Yield and other mass-related metrics such as atom economy, reaction mass efficiency and mass intensity have been examined by Constable et al with regard to their significance concerning greenness and costs. The importance of using a (product) concentration term, which can be mass intensity or mass index, is additionally emphasized by Laird et al This is in compliance with Winterton, who in his twelve more green chemistry principles demands the establishment of full mass balances. 

Although the asymmetric isomerization of allylamines has been successfully accomplished by the use of a cationic rhodium(l)/BINAP complex, the corresponding reaction starting from allylic alcohols has had a limited success. In principle, the enantioselective isomerization of allylic alcohols to optically active aldehydes is more advantageous because of its high atom economy, which can eliminate the hydrolysis step of the corresponding enamines obtained by the isomerization of allylamines (Scheme 26). 

Measurements of the chemistry and process efficiency are attempts to address Green Chemistry Principles 2 (atom economy) and 8 (reduce derivatives). Atom economy is one of the most widely known measures of chemistry efficiency [43-45] and is calculated from... 

At least one of the 12 principles—number 2, design safe products—is a must for pharmaceutical synthesis. Indeed, pharmaceutical products are regulated and tested for safety. Principle number 7, maximize atom economy, refers to a metric against which the greenness of a process may be evaluated. Green metrics are covered in the next section. 

This chapter outlines the principles of green chemistry, and explains the connection between catalysis and sustainable development. It covers the concepts of environmental impact, atom economy, and life-cycle analysis, with hands-on examples. Then it introduces the reader to heterogeneous catalysis, homogeneous catalysis, and biocatalysis, explaining what catalysis is and why it is important. The last two sections give an overview of the tools used in catalysis research, and a list of recommended books on specialized subjects in catalysis. 

Examine the list of the 12 principles of green chemistry shown at the beginning of this chapter. Which of these principles relate to the concepts of atom economy, the E-factor, and the environmental quotient Q ... 

Integration of green chemistry principles into pre-lab and post-lab questions is another easy and effective inclusion method. The synthesis of aspirin is a common first-year lab procedure. One of the fundamental principles of green chemistry is atom economy. A possible pre-lab question might be to have the students calculate the percent atom economy of the synthesis using the following equation ... 

The most frequently discussed green chemistry topic was catalysts, followed by the synthesis of ibuprofen, ionic liquids, supercritical solvents, atom economy, pesticides, polymers, renewable feedstocks, and the principles of green chemistry. Other green chemistry topics that were found included... 

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