recap

Name the 12 principles of Green Chemistry

Waste prevention

Atom economy

Less hazardous chemical synthesis

Designing safer chemicals

Safer solvents and auxiliaries

Design for energy efficiency

Use of renewable feedstocks; Reduce derivatives

Catalysis

Design for degradation

Real-time analysis for pollution prevention

Inherently safer chemistry for accident prevention.

Summarise Principle 1: Waste Prevention

Design reactions and processes to prevent waste formation rather than treating waste after it is produced.

Summarise Principle 2: Atom Economy

Maximise incorporation of all reactant atoms into the desired product to minimise waste.

Summarise Principle 3: Less Hazardous Chemical Synthesis

Use reagents and methods that minimise toxicity, explosiveness, and corrosiveness.

Summarise Principle 4: Designing Safer Chemicals

Design chemicals with reduced inherent hazard while maintaining function (risk = hazard × exposure).

Summarise Principle 5: Safer Solvents and Auxiliaries

Minimise solvent use or replace hazardous solvents with safer alternatives.

Summarise Principle 6: Design for Energy Efficiency

Reduce energy demand by operating at lower temperatures, pressures, and shorter reaction times.

Summarise Principle 7: Use of Renewable Feedstocks

Replace non-renewable petrochemical feedstocks with renewable resources such as biomass or CO₂.

Summarise Principle 8: Reduce Derivatives

Avoid unnecessary derivatisation such as protecting groups that add steps, waste, and energy use.

Summarise Principle 9: Catalysis

Prefer catalytic processes over stoichiometric ones to improve efficiency, selectivity, and sustainability.

Summarise Principle 10: Design for Degradation

Design chemical products to break down into non-persistent, innocuous substances after use.

Summarise Principle 11: Real-time Analysis for Pollution Prevention

Monitor reactions in real time to prevent over-processing, waste, and pollution.

Summarise Principle 12: Inherently Safer Chemistry for Accident Prevention

Choose substances and reaction conditions that minimise risks of fires, explosions, and releases.

Atom economy formula

(Mr of desired product ÷ Σ Mr of all reactants) × 100

High atom economy means

Less waste and improved sustainability.

E-factor formula

Mass of waste ÷ mass of product.

Low E-factor means

A more sustainable chemical process.

Risk equation

Risk = Hazard × Exposure.

Green chemistry focuses on reducing

Hazard rather than exposure.

name general risks/drawbacks from chemical processes

• energy consumption: high temp+ pressure for long periods of time , explosive risk - USE AMBIENT CONDITIONS, OR ADD ABUNDANT CATALYST

• health risks = carcinogens , reproductive issues , flammability

• safety ; skin burns, toxicity , flammability (needs to be stored correctly or with an inert atmosphere which is less energy efficient), explosive

• environment ; aquatic life toxicity , ground water toxicity, soil contamination, toxicity to non target organisms - USE BIODEGRADEABLE MATERIALS

• large organic solvent use : heavy carbon footprint , toxic USE ETHANOL, WATER, ETOAC, MECHANOCHEM , RECYCLE SOLVENT

• metal choice = scarcity and expense for starting materials and reactants USE ABUNDANT METALS FE/NI

• persistent chemicals - non biodegradable , TRY RECYCLE OR REUSE, REPLACE W/ BIODEGRADEABLE ONES

• high stoichiometry= waste USE CATALYST INSTEAD

• multiple steps, protecting groups = every step increases carbon footprint USE SELECTIVE CATALYST OR ONE STEP CATALYSIS INSTEAD

• high e factor and low atom economy

• non renewable feedstock = global warming + gas emisions- rekl USE PAPER MILL SLUDGE, BIOMASS, SUGARS , PHAs, CO2

• greenhouse gases by products = NO2

• lack of real time analysis

Why are precious metals a sustainability risk?

They are scarce, expensive, and have supply-chain issues.

what is mechanochemistry and what are the sustainability benefits

• NO SOLVENT , less waste

• less energy, no cooling and heating

• improved safety

Two greener solvents to replace DCM or benzene

Ethanol and ethyl acetate.

Green alternative to Pd or Pt catalysts

Fe or Ni base-metal catalysts.

Why does catalysis improve sustainability?

Lower energy use, higher selectivity, less waste.

Why use renewable feedstocks?

They reduce reliance on fossil resources.

examples of renewable feedstocks

• starch

• cellulose

• glucose ( sugars)

• waste biomass

• co2, water, n2

• ethanol

give examples of sustainable solvents

• water

• ethanol

• ScCO2

• EtOAc

• EtOH

drawbacks of incineration

• energy consumption = small possibly volatile molecules w/ short chains

• smaller molecules = more difficult to manage

drawbacks of DCM

• health and safety risk

• heavy carbon footprint =have to remove and sep solvent at end of reaction

• energy consumption

drawbacks of an inert atmosphere

• - high energy requirements , many hours , high energy consumption