Green chemistry Flashcards
12 Principles of Green Chemistry
- prevention of waste product
- atom economy
- designing safer chemicals
- design for degradation
- design for energy efficiency
- reduce derivatives
- catalysis
- use renewable feedstocks
- safer solvent and auxiliaries
- less hazardous chemical synthesis
- realtime analysis for pollution prevention
- inherently safer chemistry for accident prevention
Select 5 out of the 12 Principles of Green Chemistry, and explain them briefly in the
context of analytical chemistry methodology.
- prevention of waste product: here we avoid the waste because is better to avoid waste than cleaning them after being created
2.less hazardous chemical synthesis: chemical methods should be designed to use and generate substance that are less or no toxic to human being and environment.
- designing safer chemical: chemical product should be designed to preserve efficacy while reduction toxicity
- safer solvent and auxiliaries: use of auxiliaries substance must made unnecessary whenever possible and choose greener ones when used.
5.reduce derivatives: unnecessary derivatization should be minimized or avoided because those steps require additional reagents which increase waste
- design of degradation: chemical product must be designed in the way that at the end of their function they should break down into harmless degradation product that do not persist in the environment
What are the biggest challenges to achieve greener analytical chemistry methods?
- new green extraction solvent
- solventless sample preparation technique
- searching for new direct “in-setu” analytical technique
- faster energy- efficiency technique
- miniaturization and hyphenation
- assessment of environmental performance
Explain 4 aspects biggest challenges to achieve greener analytical chemistry methods
- new green extraction solvent: solvent is important for chemical reaction to proceed. so we can choose solvent that have fewest lifecycle to the environment impact, less toxicity, and which reduce energy requirement.
- solvent-less sample preparation technique: this technique they is no use of solvent at all so heat or pressure are used to produce extract.
- miniaturization and hyphenation: this can be achieved by downscaling every single step in analytical process including sample preparation, extraction,… and by combining analytical technique such as HPLC and MS to perform complex precess without having to preform every individual method
- faster energy- efficiency technique; energy waste must be reduced by conducting synthetic process at appropriate temperature and pressure.
what is green solvent and List examples of so called “green solvents”,
green solvents are organic solvent that are harmless to the human and environment.
example: heptane, supercritical carbon dioxide, water, and ethanol.
Why is supercritical carbon dioxide considered a green solvent? Motivate
supercritical carbon dioxide is nonflammable, non toxic, chemically un reactive and is produced as byproduct all that characters define greener solvent.
What are the requirements for a solvent to be considered green? List 4 aspects.
- less toxic to human and environment
- naturally occurring
- produced from renewable product
- produced as byproduct
- energy efficiency in terms of production and usage.
Can you think of any contradictory aspects with regard to if hexane or heptane is the
greenest solvent?
heptane is greener than hexane,
the lower toxicity of heptane make it safer than hexane due to hexane low viscocity
Describe the approaches
- Environment, health and safety (EHS); and
1) environment: air pollution, water pollution and biodegradability
2) Health: chronic toxicity, acute toxicity and irritability
3) safety: inflammable, reactivity, release potential
what are conventional organic solvents that perform well in
terms of EHS
methanol, ethanol, propanol and butanol
Describe the approaches
- Life cycle assessment (LCA) as approaches to describe greenness (for instance of a solvent).
life cycle assessment: is useful tools used to get picture of product’s or process impact on the environment.
approaches:
- assessment of environment impact: solvent must be produced from natural resources and renewable product.
- the aim and scope of product must be defined and make sure that is environmental friendly.
Define the following concepts being part of Life cycle assessment (LCA)
1. Functional unit
2. System boundaries
3. Hot-spot analysis
4. Effect-category
- Functional unit: refers to the quantity of the product or product system based on the performance it deliver on its end used application.
- System boundaries: refers to the boundaries defined between product being studied and the surround system for instance geographical boundaries, boundaries of time and boundaries to ward product capital
- Hot-spot analysis: refers to the processes and activities that contribute to the total environmental impact by developing more detailed sustainability information.
- Effect-category: refers to characterization of different discharged with same effect into one common unit. or it can be based on scientific analysis.
Miniaturization and hyphenation are two approaches in green analytical chemistry – Motivate why
- miniaturization is the downscaling every single step in the analytical process including sample preparation or extraction… so by doing this the amount of solvent and waste generated are reduced.
- hyphenation: is combination of analytical technique for example HPLC-LC to solve complex problem without performing individual technique. so, this will minimize the solvent used, energy and waste generated.
Why is in-situ analysis considered a green analytical chemistry approach?
in-situ analysis:(find answer)
You would like to compare two different analytical methods in terms of their environmental impact. How would you do this? Will you use any methods/tools to enable the comparison
(not sure about this answer)
i can use LCA tool ( life cycle assessment) and EHS
by:
- comparing similar product
-and identify hot-spot
