Brief Intro
Natural resources are converted into useful products.
Bulk chemicals produced on a large scale b/c there is a larger demand for them.
Fine chemical are produced on a smaller scale.
They’re used as feedstock’s (reactants bought by other manufacturers).
How to achieve a greener industry
- Renewable sources
- Fewer use of hazardous chemicals
- Increased energy efficiency
- Reduce waste + pollution
- Higher yield
The work of the chemical industry 1A
Jobs
Maintenance worker: Fixes problems with machines
Transport workers: Brings materials into the plant
Research chemists: Investigate the best method
Production chemists: “Scale up” the methods
Analytical chemists: Test the purity of samples and see if it measure up to standards.
Technical team: Monitor data + conditions
Chemical process
- These raw materials are converted into chemicals and purified into feedstocks after being heated and compressed.
- Crude oil 2)Air 3) Water
- The synthesis takes place in the reactor and is converted into the product à Energy is released.
– Some CR’s take place in high temp. so need heat energy
- Uses catalyst
- The mixture of chemicals is separated into: Product, by-products, unchanged material (recycled).
- Heat energy is produced as a by-product b/c so it is used to make steam in the exchanger à saves money + energy
- The product is analysed to monitor purity.
Products made from synthesis
- Basic organics
- Petrochemicals
- Pigments, paint, dyes
- Pharmaceutical
- Speciality chemicals
Innovations in green chemistry 1B
Regulations are put in place for the storing and transporting of chemicals. Hazard symbols and sealed containers prevent harm from coming to people + environment.
Preventing pollution: 1) New method 2) Use renewable + cost effective resources
Green chemistry benefits:
- Increases efficiency 2) Reduces cost 3) Avoid risks
Reducing use of petrochemicals, e.g. crude oil, will be more sustainable.
Rather, you should ferment renewable plant material using bacteria à produces MALANIC ACID à produces sorona à used for clothes
| Advantages | Disadvantages |
| Renewable | Takes up land meant for food |
| Less energy used | Energy needed to produce more fertilisers + for harvesting |
| Fewer emissions | |
| Saves crude oil |
Yields
Yield – efficiency of method
- Compares quality with predicted quality
High yield = good but doesn’t mean that process is “green”.
Working out percentage yield
E.g. 10g of CaCO3 is heated for 20mins. The product is 4.8g of CaO. What is the percentage yield?
- Formula: CaCO3 (s) à CaO (s) + CO2 (g)
- Atoms that end up in the product are referred to as green. Waste products are brown.
- Find RFM: CaCO3 = 40 + 12 + (16 x 3) = 100 CaO = 40 + 16 = 56
So, 100g of CaCO3 produces 56g of CaO.
- Theoretical yield: 56/100 x 10 = 5.6g [from 10g of CaCO3 ]
- % yield: Actual yield / theoretical yield
- / 5.6 x 100 = 7%
Atom economy
= the efficiency à how much product ends up as reactant
Formula: RAM of product / RAM of reactant x 100
E.g. CaCO3 (s) à CaO (s) + CO2 (g)
RAM =100 RAM=56 RAM=44
Atom economy: 56 / 100 x 100 = 5.6%
Avoiding hazardous chemicals
Need to replace toxic reactant with safer alternatives.
Copper catalyst means that process runs under milder conditions = save energy + costs.
Energy efficiency
Heat energy is used for: 1) drying 2) reactions 3) process waste 4) separate + purify
To prevent energy loss, must: Install efficient insulation in pipes + stop steam from escaping leaking valves
Exothermic reactions release energy which is used to make steam to generate electricity = NO BILLS for extra energy
Catalyst
Catalysts speed up CR’s for the DESIRED product NOT the unwanted product.
PROs of catalysts
- Reduces waste
- Lower temp. required à good for environment
- Saves energy
Need to find ways to lower energy demand.
Biocatalyst – enzymes produced by microorganisms
- Operates within limited temp. + pH range à any higher = denatured
Petrochemical route has more steps = more energy + money spent
Heat exchangers have two materials flowing in opposite directions. The hot material is cooled by the colder one.
Recycling
Install distillation units to separate desired chemicals from waste gases. This will reduce waste.
Convert old polymer to monomer à re-polymerise pure monomer à fresh feedstock à new polymer.
Use by-products to make another product.
Need to remove harmful chemicals from air / water / landfills.
Closed loop – use waste material to manufacture the same product + there is no loss in quality
Open loop – waste is recovered to manufacture lower quality product
- Not as good value but cuts down on the amount of fresh feedstock required
Designing new catalysts
Wrap organic structure around metal ion to make a new catalyst.
Catalyst for making polyester:
Wrap citrate ions around titanium ions to produce a polymer. This titanium can be used as antimony to replace toxic metals.
You need to think about the size+ shape of the molecules, as well as the interaction with electrons.
PRO’s of new catalysts
- More efficient b/c less catalyst is needed to make a fixed amount of polymer
- The new catalyst metals aren’t toxic
- New catalyst à new polymers
Sustainable development – meeting needs of present without compromising needs of future
Green chemistry – long term sustainability + short term impacts on health + environment