Green chemistry
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Transcript of Green chemistry
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GREEN CHEMISTRY
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TWELVE PRINCIPALS OF GREEN CHEMISTRY 1. PREVENTION
2. ATOM ECONOMY3. LESS HAZARDOUS4. DESINING SAFER CHEMICALS5. SAFER SOLVENT AND AUXILIARIES6. DESING FOR ENERGY EFFICIENCY7. USE OF RENAWABLE FEEDSTOCKS 8. REDUCE DEGRADATIO9. CATALYSIS10.DESING FOR DEGRADATION11.RT ANALYSIS FOR POLLUTION PREVENTION12.INHERENTLY SAFER CHEMISTRY FOR
ACCIDENT PREVENTION
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1. PRINCIPAL
PREVENTION
Pollution prevention act of 1990 focus on reducing or eliminating waste at the source by modifying production process, promoting the uses of non toxic or less toxic substances , implimanting conservation techniques and reusing material rather than putting them into the waste system
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HARPINS :- Harpin’s are naturally occuring protein and are non toxic . Harpin’s proteins trigger a plants natural defense systems to protect against disease and pests and simultaneously activate certain plant growth systems without altering the plants DNA
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Atom economy is an important concept of green chemisty
philosophy. Atom economy can be written as.
% ATOM ECONOMY =
MOLECULAR WEIGHT OF DESIRED PRODOCT
_____________________________________________
X 100
MOLECULAR WEIGHT OF ALL REACTANTS
2nd
Principal
ATOM ECONOMY
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A measure of the efficincy of a reaction. Atom economy, in contrast to percent yield, take into chemist with a means to quantify how many atoms are turned into useful product vs. those atom turns into waste.
HOW THE ATOM ECONOMY IS RELATED TO GREEN CHEMISTRY?
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It is fundamental in chemical reaction of the form A+B _____ C+D That two products are necessarily generated though product C may have been the desired one. That being the case , D is considered a byproduct. As a significant goal of chemistry to maximize the efficiency.
Creating reaction utilizing atom economy
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3rd principal
Designing safer solvent1. List of substances to avoid, often called
a BLACK LISTS This included. Methelene chloride Trichloroethylene Lead Organo-tin compound Chlorinated paraffins Phthalates Nonylphenolethoxylate Brominated flame retardant
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• 1st METHYLENE CHLORIDE: COLOURLESS LIQUID WITH CHOLOROFORM LIKE ODOUR
APPLICATION ; It have many industrial application
1. Paint striping.
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2ND Pharmaceutical manufacturing.
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3RD Paint remover manufacturing.
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4th application metal cleaning and degreasing
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METHEYLENE CHLORIDE
EFFECT ON HUMAN
temporary cornear damage
Caused server burns and
swelling in the throat of a man
Crosses the placental barrier Memory loss
speech problem and balance
problem
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Potential for methylene
chloride to build up accumulate
in body
Well absorb through the lungs,intestine and skin
It is converted to co and co2 in the body
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Trichloroethylele;
Harmful effect on human
Abdominal pain and signs and
symptoms central nervous system depression,
Reddening of the skin, irritation
Caused smarting pain and injury to the surface tissue of the
eye.
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LEAD;
Harmful effect on human
Loss of appetite,n
ausea,
Difficult in sleeping,
moodiness,
Anemia and decreased
sexual drive.
Damage to the blood forming,
nervous, urinary, and reproductive
system
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4th principal renewable feedstocks
Feedstocks that are suitable for the process include plant- derived as soybean, rapeseed and palm. However in the future non-edible oils such as Jatropha and Alga oils will become increasingly important sources of Ecofining feedstock
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SOLVENT Green solventTypes of green solvent
Ungreen solvent
Types of ungreen solvent
Water Ionic liquids Supercritical
co2 Bio etahnol
Toluene Acetone VOCs benzene
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1st green solvent Water Water can be used as solvent for grignard and
other formerly water incompatible reaction for some reaction there is no need for the reagent to be soluble in water
Primary disadvantages; large amount of energy of time that often must be expended in order to sufficiently separate the product from the water before the product can be used and the water discarded.
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Supercritical water it differ from the liquid water in being able to readily dissolve both organic compounds and gases.
.
SUPERCRITICAL WATER
Primary disadvantages ;-
very high temperature
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A. They are highly polar. Few are volatile such as dimethylammonium dimethylcarbamate. Some are less polar such as tetralkylphophonium ionic liquid mad by cytec canada.
IONIC LIQUIDS
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Bio ethanol Ethanol facts: Environment Ethanol is an renewable fuel
produced from plant, unlike petroleum-based fossil fuels that have a limited supply and are the major contributor of carbon dioxide9 (co2) emissions,a greenhouse gas (GHG)
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Facts of ethanol1st fact :- ethanol reduced smog
pollution.
2nd fact :- ethanol has a positive energy balance.
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3rd fact :- water usage in ethanol production is declining 4th fact :- ethanol is rapidly biodograded in surface water ground water and soil.
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Supercritical co2
Supercritical carbon dioxide refers to carbon dioxide that is in the fluid state while also being at or above both its critical temprature or pressure ,supercritical co2 is forced through the green coffee bean and they are sprayed with water at high pressure to caffeine.
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Uses of supercritical co2 Used as a more environmentally friendly
solvent for dry cleaning.
Used as more than 30 years to enhance oil recovery in mature oil field.
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Ungreen solvent VOC’S Volatile organic compounds are
compound that have a high vapour pressure and water stability
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VOC’s
Sources :- many VOCs are human made
chemicals that have been used and produced in the manufacture of paints, pharmaceuticals and refrigerants. They are often components of petroleum fuels, hydraulic fluids, paint thinner and dry cleaning agents.
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Where do they come from ? paints and lacquers, paint strippers,
cleaning supplies, carbon less copy papera etc.
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Harmful effect
on Human health
irritation
Nose and throat
discomfort
nausea
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Environmental effect Volatile organic compound play a large role as that
react in the air with nitrogen oxides and sunlight to form ozone . Because of this the EPA (environmental protection agency) has determined that controlling volatile organic compound is an effective method for minimizing ozone levels.