Principles of Green Chemistry

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Catalyst Noun

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[kat-l-ist]

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Catalyst

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A substance that increases a chemical reaction's rate by providing a lower energy pathway without being consumed in the process.

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Example: This diagram shows a catalytic converter where catalysts (red and blue dots) speed up the chemical reaction that changes harmful car exhaust into safer gases.

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By-product Noun

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[bai-prod-ukt]

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By-product

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A substance produced during a chemical reaction in addition to the main, desired product, often contributing to chemical waste.

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Example: In the combustion of methane to produce energy, carbon dioxide and water are created as secondary substances, or by-products, of the main reaction.

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E-factor Noun

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[ee-fak-ter]

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E-factor

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A metric measuring waste efficiency, calculated as the total mass of waste generated divided by the mass of the product.

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Example: This image uses candies to show a chemical reaction that produces a large amount of waste compared to the small amount of desired product.

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Process Mass Intensity Noun

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[pro-ses mas in-ten-si-tee]

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Process Mass Intensity

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A metric measuring process efficiency, calculated as the total mass of all inputs divided by the mass of the final product.

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Example: This formula shows that Process Mass Intensity (PMI) is the ratio of the total mass of all materials used (inputs) to the mass of the final desired product.

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Atom Economy Noun

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[at-uhm ee-kon-uh-mee]

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Atom Economy

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A measure of reaction efficiency, calculated as the mass of the desired product divided by the total mass of reactants.

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Example: This image shows a chemical reaction where all starting atoms (reactants) are used to make the final substance (product), demonstrating 100% atom economy with no waste.

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Auxiliaries Noun

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[awk-zil-yuh-reez]

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Auxiliaries

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Substances like solvents or separation agents that facilitate a reaction but are not incorporated into the final product.

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Example: This image shows a solvent (an auxiliary substance) being used to dissolve a solute, forming a solution. In green chemistry, the goal is to reduce or replace such auxiliaries.

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Solvent Noun

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[sol-vuhnt]

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Solvent

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A substance, usually a liquid, capable of dissolving other substances to form a uniform mixture called a solution.

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Example: This diagram shows water molecules (the solvent) pulling apart and surrounding the ions of a solid, causing it to dissolve into a solution.

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Carcinogen Noun

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[kar-sin-uh-juhn]

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Carcinogen

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A substance, radionuclide, or radiation that is an agent directly involved in causing cancer in living tissue.

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Example: This diagram shows the effect of a carcinogen by comparing orderly normal cells to the messy, uncontrolled growth of cancer cells that form a tumor.

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Distillation Noun

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[dis-tuh-ley-shuhn]

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Distillation

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A purification process involving the selective boiling and subsequent condensation of components from a liquid mixture to separate them.

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Example: This diagram shows distillation, a process where a mixture (salt water) is heated to create vapor, which is then cooled in a condenser to become a purified liquid.

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Reverse Osmosis Noun

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[ri-vurs os-moh-sis]

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Reverse Osmosis

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A purification process that uses a partially permeable membrane to separate ions and unwanted molecules from a solution.

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Example: This diagram shows pressure forcing small water molecules through a membrane from salt water to fresh water, while larger salt molecules are blocked.