29 papers of Perkin Transactions1 (year 2000) -31% chlorinated solvents

29 papers of Perkin Transactions1 (year 2000)

-31% chlorinated solvents

-35% dipolar aprotic solvents such as D/MF

-24% noxios solvents such as benzene and pyridine

-one paper water as the solvent

29 papers of Perkin Transactions1 (year 2000)

-31% chlorinated solvents

-35% dipolar aprotic solvents such as D/MF

-24% noxios solvents such as benzene and pyridine

-one paper water as the solvent

•Transportation – production of gasoline and diesel from petroleum,

fuel additives for greater efficiency and reduced emissions, catalytic

converters, plastics to reduce vehicle weight and improve energy

efficiency.

•Clothing – man-made fibres such as rayon and nylon, dyes, water-proofing

and other surface finishing chemicals.

•Sport – advanced composite materials for tennis and squash rackets,

all-weather surfaces.

•Transportation – production of gasoline and diesel from petroleum,

fuel additives for greater efficiency and reduced emissions, catalytic

converters, plastics to reduce vehicle weight and improve energy

efficiency.

•Clothing – man-made fibres such as rayon and nylon, dyes, water-proofing

and other surface finishing chemicals.

•Sport – advanced composite materials for tennis and squash rackets,

all-weather surfaces.

•Safety – lightweight polycarbonate cycle helmets, fire-retardant

furniture.

•Food – refrigerants, packaging, containers and wraps, food processing

aids, preservatives.

•Medical – artificial joints, ‘blood bags’, anaesthetics, disinfectants,

anti-cancer drugs, vaccines, dental fillings, contact lenses, contra-ceptives.

•Office – photocopying toner, inks, printed circuit boards, liquid-crystal

displays.

•Home – material and dyes for carpets, plastics for TVs and mobile

phones, CDs, video and audio tapes, paints, detergents.

•Farming – fertilizers, pesticides.

•Safety – lightweight polycarbonate cycle helmets, fire-retardant

furniture.

•Food – refrigerants, packaging, containers and wraps, food

Processing aids, preservatives.

•Medical – artificial joints, ‘blood bags’, anaesthetics, disinfectants,

anti-cancer drugs, vaccines, dental fillings, contact lenses, contra-ceptives.

•Office – photocopying toner, inks, printed circuit boards, liquid-crystal

displays.

•Home – material and dyes for carpets, plastics for TVs and mobile

phones, CDs, video and audio tapes, paints, detergents.

•Farming – fertilizers, pesticides.

THE TWELVE PRINCIPLES OF GREEN CHEMISTRY

1. It is better to prevent waste than to treat or clean up waste after it is formed

Chromare & Nitrite corrosion inhibitorCerium corrosion inhibitor

Common fertilizer(P+N) Soya base fertilizer(N 7% )

O

OCl

Cl Cl

Cl

2,3,6,7-tetrachlorodibenzo-4-dioxin

TCDD

O

OCl

Cl Cl

Cl

2,3,6,7-tetrachlorodibenzo-4-dioxin

TCDD

-Because of low polarity of dioxins and furans, like many other organochlorine compounds, are far more soluble in the fatty tissues of animals than they are in water.

-When these compounds enter the animal they are not readily exerted and tend to accumulate in fatty tissues that we call it bioaccumulation.

-So can result in an animal having significantly higher concentrations of the organochlorine compound in its body than in the surronding environment .

-At each higher level of the food chain there is an increasing concentration of the contaminant.This is known as biomagnification.

-The combined effects of bioaccumulation and biomagnification can make the contaminant levels in fish up to 100000 times greater than that of their suuronding environment.

-Because of low polarity of dioxins and furans, like many other organochlorine compounds, are far more soluble in the fatty tissues of animals than they are in water.

-When these compounds enter the animal they are not readily exerted and tend to accumulate in fatty tissues that we call it bioaccumulation.

-So can result in an animal having significantly higher concentrations of the organochlorine compound in its body than in the surronding environment .

-At each higher level of the food chain there is an increasing concentration of the contaminant.This is known as biomagnification.

-The combined effects of bioaccumulation and biomagnification can make the contaminant levels in fish up to 100000 times greater than that of their suuronding environment.

FeIII

N

NN

N

O

O

O

OO

H H

R

R

X

X

Cat+=Li+, [Me4N]+, [PPh4]+

X= Cl, H,OCH3

TAML ACTI VATOR

TAML ACTI VATOR

2. Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product.

The classic evaluation of effectiveness and efficiency of a synthesis is yield. Yield also totally ignores the use or generation of any undesirable products that are an intrinsic part of synthesis.. It is possible and very often the case that a synthetic pathways, or even a synthetic step can achieve 100% and generate waste that is greater in mass and volume than that of the desired product.

The standard synthetic transformation types can be evaluated generically to determine the intrinsic atom economy of each type.

1) Rearrangement

2) Addition

Trans Cis

C==C + A-B C C

A B3) Substitution

4) Elimination

BA

CC C==C

C C

A B

+ D

A

CC

D

Efficiency of a Reaction

Percentage yield= (actual yield/theoretical yield) X 100

Topic: Atom Economy• A Measure of the Efficiency of a

Reaction and is an assessment in which one looks at all of reactants to measure the degree to which each of them is incorporated into the final product.

ATOM ECONOMY“Because an Atom is a Terrible Thing to Waste”

• How many of the atoms of the reactant are incorporated into the final product and how many are wasted? Infusing green chemistry into organic.

Atom Economy in a Substitution Reaction

Equation 1bNa Br H2SO4 NaHSO4 H2O+ + + +CH3 CH2 CH2 CH2 OH CH3 CH2 CH2 CH2 Br

1 2 3 4 5 6

Equation 1a

0.08g 1.33 2.0 1.48 g (theoretical yield)

0.0108mole 0.0129 0.0200 0.0108 mole (theoretical yield)

Compound 1 is the limiting reagent

Suppose the actual yield is 1.20 g of compound 4.


= (1.20 g/1.48 g) X 100 = 81%

CH3CH2CH2CH2OH NaBr H2SO4 CH3CH2CH2CH2Br NaHSO4 H2O+ + + +1 2 3 4 5 6

% Atom Economy = (FW of atoms utilized/FW of all reactants) X 100 = (137/275) X 100 = 50%

Table 4 Experimental Atom Economy of Equation 1: Based on Actual Quantities of Reagents Used

% Experimental Atom Economy = (mass of reactants utilized in the desired product/total mass of all reactants) X 100 = (theoretical yield/total mass of all reactants) X 100 = (1.48 g/4.13 g) X 100 = 36%

% Yield X Experimental Atom Economy

% Yield X Experimental Atom Economy = (actual yield/theoretical yield) X (mass of reactants utilized in the desired product/total mass of all reactants) X 100

%PE .EAE= (actual yield/theoretical yield) X (theoretical yield/total mass of all reactants) X 100 = (actual yield/total mass of all the reactants) X100

= (1.20 g/4.13 g) X 100 = 29%


= (1.20 g/1.48 g) X 100 = 81



%PE .EAE= (actual yield/theoretical yield) X (theoretical yield/total mass of all reactants) X 100 = (actual yield/total mass of all the reactants) X100 = (1.20 g/4.13 g) X 100 = 29


= (1.20 g/1.48 g) X 100 = 81



%PE .EAE= (actual yield/theoretical yield) X (theoretical yield/total mass of all reactants) X 100 = (actual yield/total mass of all the reactants) X100 = (1.20 g/4.13 g) X 100 = 29

GREEN CHEMISTRY

• The Synthesis of Ibuprofen– Advil, Motrin, Medipren– 28-35 million pounds of ibuprofen are

produced each year (37-46 million pounds of waste)

Since about 15 million kg of ibuprofen are

produced each year, this translates into more

than 17.5 million kg of waste generated each

year from the synthesis of ibuprofen!

Since about 15 million kg of ibuprofen are

produced each year, this translates into more

than 17.5 million kg of waste generated each

year from the synthesis of ibuprofen!

The Boots Synthesis of IbuprofenAtom Economy

% Atom Economy = (FW of atoms utilized/FW of all reactants) X 100 = (206/514.5) X 100 = 40%

The BHC Synthesis of Ibuprofen Atom Economy

3. Wherever practicable, synthetic methodologies should be designed to use and generate substances that possess little or no toxicity to human health and the environment

Ni-Al2O3 Co-CO2

370-800psi 120-140psi

370-800psi

Ni-Al2O3

+

O OH

CO2HH2OC

OH

OH

OH

OHOH OH

OHO

CO2H

E.ColiE.Coli

CO2HH2OCCO2H

H2OCH2 Pt

370-800

R

CN

3HC

O O

O

CH3+ +

CN

R

CH3OH + CO2

3HC

K2CO3

LD50 &LC50.

LD and LC stand for lethal dose and lethal concentration respectively.LD50 is the dose of a chemical at which 50% of a group of animals(usually rats or mice) are killed, whilst LC50 is the concentration in air or water of the chemical which kills 50% of test animals. These tests are the most common ways of measuring the acute toxicity of chemicals.

LD50 tests are done by injecting, applying to the skin or giving orally a known dose of pure chemical. The result is usually expressed in terms of milligrams of chemical per kilogram of animal, e.g. LD50 (oral, rat) –10 mg kg –1 means that when given orally at the rate of 10 mg kg -

1animal weight the chemical will kill 50% of rats tested.

Similarly LC50 tests are usually carried out by allowing the animal to breathe a known concentration of the chemical in air, results being expressed in parts per million(ppm) or milligrams per cubic metre (mg m3).

4. Chemical products should be designed to preserve efficacy of function while reducing toxicity.

The balance btwn maximizing the desired performance and function of chemical product while ensuring that the toxicity and hazard is reduced to its lowest possible level is the goal of designing safer chemicals

CH2CH2CN CH3CHCN

OH OH

rat oral LD50=45 mmol/Kg rat oral LD50=1.23 mmol/Kg

R

CN

OH

R

O

RR

+ HCN

R-CH2-CN R-CH-CN.

R-C-CN

Me

Me

Mechanism of action analysis:Direct toxicity: Chemical substance itself that is reacting to cause the end effect of concernIndirect toxicity: it is metabolite or derivative of the original substance that is responsible for harmful interaction with the body

SAR(structure activity relationships):SAR are based on a correlation btwn the molecular architecture of a compond and its activity

Avoid the use of functional group that posses some toxicity:Isocyanate base adhesive Acetoacetate esters

Vinyl solfone base dye Vinyl solfone sulfatebase dye

Mask the functional group that posses some toxicity

Minimizing bioavailability:The ability to enter the various biological systems and organs is called bioavailability

Minimizing auxiliary substances:Innocuous coating need to be dissolved in hazardous solvent Coating with the same properties but can be used in aqueous systems

5. The use of auxiliary substances (e.g. solvents, separation agents, etc.) should be made unnecessary whenever possible and, innocuous when used.

1)Concern for solvents2)Environment3)Supercritical fluids4)Solventless5)Aqueous6)Immobilized7)Ionic Liq.

CH2Br CH2BrCH3CH3

Br

HVNBSCO2[SC]40 C139 barAIBN4hours

HV40 CBr2

CO2[SC]

252 barK2CO3

5MIN

+

100% 75% Minor Product

3)Supercritical fluids

CO2 benefits

1)Nonflammable

2)Nontoxic

3)Chemically unreactive

4)Cheaply recovered byproduct from the production

of ammonia and from natural gas wells

5)It can be recovered, purified and reused

CO2 benefits

1)Nonflammable

2)Nontoxic

3)Chemically unreactive

4)Cheaply recovered byproduct from the production

of ammonia and from natural gas wells

5)It can be recovered, purified and reused

O

O

O

OO

OHR

+

R OH O

O

O

O

OH

OO

R O

NH4+MeCO3

-

-H20

4)Solventless

NNH2

O+

NH

H2O220 C

5)Aqueous

+

OH

OH

OH

H2O

220C

Isomerization of geraniol

[ ] n

O

O

6)Immobilized

ZnClMeNCH2CH2OH

Me

Me

+ 2Ionic Liq.

Choline chloride

7)Ionic Liq.

•Good solvent for awide range of inorganic and organic materials

•Often composed of poorly co-ordinating ions and can therefore be highly polar yet non co-ordinating

•No effective vapour pressure

•Liquid range of 300 ºC allowing tremendous kinetic control

•Thermally stable up to 200 ºC

•Their water sensitivity does not affect their industrial applications

•Immiscible with a number of organic solvents and provide non-aqueous polar alternatives for two phase systems

•Relatively inexpensive/easy to prepare

THE GREEN ASPECTS

1)The high solubility of ionic liquids implies that only small reactor volumes are required thus reducing waste from synthetic processes.

2) Also since they are often composed of poorly co-ordinating ions there is a great potential for very high recovery and hence recycling of the solvent.

3)The fact that they have no effective vapour pressure and a large liquid range means that ionic liquids, even if used at high temperatures, do not release harmful vapours thus reducing the amount of volatile organic compounds released into the atmosphere.

.Perfect candidates for biphasic catalysis(cleaning up fuel diesl and in chemical and pharmaceutical industries). Battery electrolytes. Catalyst solvent (hydrogenation with rhodium, ruthenium and cobalt complexes, oligomerisation with nickel complexes. Bronsted and lewis acidity and superacidity. Ranging from hydrophobic to hydrophilic.Water sensitive to air stable. Cheap and straight forward to prepare

6. Energy requirements should recognized for their environmental and economic impacts and should be minimized. Synthetic methods should be conducted at ambient temperature and pressure.

1)Separation.energy.requirements2)Microwaves3)Sonic4)Optimizing.the.reaction.should.mean.minimizing.the.energy.Requirement

7. A raw material feedstock should be renewable rather than depleting whenever technically and economically practical.

1) What are renewable vs. depleting feedstocks?2) Sustainability3) Direct environmental effects 4) Indirect environmental effects5) Limited supply creates economic pressure6) The political effects of petroleum7) Concern about biological feedstocksa) Seasonal supplyb) Land/energy usage

8. Unnecessary derivatization (blocking group, protection/deprotection, temporary modification of physical/chemical processes) should be avoided whenever possible.

1) The prevalence of this practice in chemistry2) Blocking/protecting groups3) Making salts, etc. for ease of processing4) Adding a functional group only to replace it

NH

Cl Cl

NO2

NH2

H2

CATALYST NH

NO2 NH2

Cl2 HNO3

H2

CATALYSTNH

NH2

NO2 NH2

+

+

+ {CH3}4N+OH-

-H2O

-H2O

NH NH

N

O

(CH3)4N+

N

O O

(CH3)4N+

_ __

9. Catalytic reagents (as selective as possible) are superior to

stoichiometric reagents.

CH3CH2CH2CH2OH + NaBr + H2SO4

CH3CH2CH2CH2Br + NaHSO4 + H2O

This reaction is actually an acid promotion Rn not an acid catalyzed Rn. This is a result of the fact that the sulfuric acid in this reaction is required in stoichiometric, not catalytic amounts. As principle 9 indicates reagent used in catalytic amount are preferable to reagents used in stoichiometric amounts. Since one mole of sulfuric acid is required for the loss of every water molecules in this reaction. Then only stoichiometric quantities of this reagent will suffice. However even if stoichiometric amounts are used then recovery / recycling / reuse of unwanted products should take place whenever this is feasible. Significant strides have been made to develop rns that are promoted by nontoxic and recoverable catalysts.

The role of catalysts is to facilitate a transformation that is desired without being consumed as part of the rn and without being incorporated in the final product. This facilitation can take several different forms including: 1) Selectivity enhancement: selective catalysis has been achieved to ensure that the degree of rn that take place is controlled (e.g. mono additions vs. multiple addition), the site of rn is contolled (c-methylations vs. o- methylations), and the stereochemistry is controlled(e.g. R vs. S enantiomer). In green chemistry both starting material utilization is enhanced and waste production is minimized.

2) Energy minimization by lowering the Ea of a rn pathway, catalytic systems not only achieve control, but also lower the emperatures. That are necessary to effect a reaction. In large scale of commodity chemical process, this energy balance issue can be the single most important factor from both an environmental and economic impact assessment point of view.

In comparing catalytic versus stoichiometric process, the advantage of catalysis is that, while a stoichiometric reagent will generate one mole of product for every mole of reagent used, a catalysts will carry out thousands , if not millions, of transformations before it is exhausted.

10. Chemical products should be designed so that at the end of their function they do not persist in the environment and break down into innocuous degradation products.

1) plastics2) pesticides3) just as you design for function, consider degradation as a function4) designing for biodegradability

Classification of groups based on the effect on biodegradation defined from literature data

Negative group Neutral group Positive group

Mono benzene NO2, X, SO3H,Quaternary CH ,NH , OCH ,Ether, COOH, OH, Ester, Amide Derivatives C, CF3,Tertiary Amine, CN, Aldehyde, OThers 2 Substituted (meta), Ortho,para 3-6 Substituted Acyclic NO , X, SO H, Quaternary CH ,NH ,OCH , Ether, COOH, OH, Ester, Amide Compounds C, CF , Tertiary Amine,CN Amide, Aldehyde

11. Analytical methodologies need to be further developed to allow for real-time in-process monitoring and control prior to the formation of hazardous substances

An area of focus within the analytical community now is to develop methods and technology that allow the prevention and minimization of the generation of hazardous substances in chemical processes.The development of process analytical chemistry for green chemistry is based on the premise that ‘ you can not control what you can not measure’. In order to effect changes on process during their operation, you need to have accurate and reliable sensors, monitors, and analytical techniques to assess the hazards that are present in the process stream. When these toxic substances are detected at even the smallest trace levels it may be possible to adjust the parameters of the process to reduce or eliminate the formation of these substance. If the sensors are interfaced directly with process controls, this hazard minimization may very well be automated.

Another example of the use of process analytical chemistry is in the monitoring of the progress of reactions to determine their completion. In many cases, chemical process require the continuous addition of reagent until the reaction is complete. If there is a real- time, in – process monitor to allow determination of completion, then the need for additional excess reagent can be obviated and potentially hazardous substances can be eliminated from use and will not find their way to the waste stream.

12. Substances and the form of a substance used in a chemical process should chosen so as to minimize the potential for chemical accidents, including releases, explosions, and fires.

In some cases where the recycling of a solvent from a process may have advantages from the perspective of pollution prevention and release to the environment, it may also increase the potential for a chemical accident or fire.Approaches to the design of inherently safer chemistry can include the use of solids or low vapor pressure substances in place of the volatile liq. Or gases that are associated with the majority of chemical accidents. Other approaches include avoiding the use of molecular halogens in large quantity by substituting reagents that carry the halogens to be transferred in a more innocuous manner. The utilization of ‘ just- in- time’ techniques involves the generation and rapid consumption of hazardous substances within a contained process.

RNH2 + COCl2 RNCO HCl RNHCO2R

URETHANE+

RNH2 RNCO H2OCO2RNHCO2RURETHANE

+ +

Monsato university

R'OH

R'OH

Process Used to Minimize or Eliminate Hazards in theTeaching Lab

•Assess the reaction conditions, focusing on solvents and reagents first. •Identify hazardous materials or inefficient procedures •Modify the process and test efficacy of new procedure •Evaluate the overall process for hazards and efficiency

29 papers of Perkin Transactions1 (year 2000) -31% chlorinated solvents

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Transcript of 29 papers of Perkin Transactions1 (year 2000) -31% chlorinated solvents