Chemistry

Project Report
On
“Green Chemistry”
Session: 2023-24

Under Supervision of Submitted

by
Mr. Abhishek Khushi
Lecturer in Chemistry Roll
No……………
Class XII (Non-
Medical)
TERI PUBLIC SCHOOL
KURUKSHETRA
 CERTIFICATE

This to certify that the project titled “Green Chemistry” has

been undertaken by Khushi, Roll No. ……………….. a student of XII

(Non-Medical). This project has been carried out as a part of Chemistry

project as prescribed by the Central Board of Secondary Education.

This work has been done by the candidate’s own efforts.

Mr. Abhishek
Lecturer in Chemistry
 ACKNOWLEDGE MENT

I express my deep sense of gratitude to Mr. Abhishek, Lecturer of

Chemistry, Teri Public School, Kurukshetra, for his inspiration, valuable

guidance and constant encouragement in the completion of this project. Without

him it would have been an impossible task for me. I have put my sincere effort

to make this project interesting. I have fully consulted all the available books on

this subject and I am thankful to esteemed authors

Khushi
Class 10+2, (Non-Medical)
Roll No. ………………….
 CONTENTS

1. Introduction

2. Green Chemistry Relevance and Goals

3. Twelve Principle of Green Chemistry

4. Tools of Green Chemistry

5. Alternative Starting Materials

6. Green Reagents

7. Organic Acid and Catechol Synthesis

8. Adipic Acid and Catechol Synthesis

9. Green Catalysts

10. Green Solvents

11. Organic Synthesis in Water

12. Green Process with Suitable Example

13. Future of Green Chemistry

 INTRODUCTION TO GREEN CHEMISTRY

Green chemistry-relevance and goals- Anastas’ twelve principles of green chemistry- Tools
of green chemistry: Alternative starting materials, reagents, catalysts, solvents and processes
with suitable examples.
Green chemistry relevance and goals.

With the ever increasing population around the globe, the natural resources were over
exploited to meet the demand for various types of chemicals and the pollution has became
inevitable. In industries, large amount of gases like CO, CO 2, SO2 and oxides of nitrogen are
produced due to burning of fuels such as coal and oil. H2S gas is produced during petroleum
refining, in coke ovens, manufacture of dyes, tanning industry, rayon manufacturing plants
etc. Industrial process such as manufacture of papers, plastics, chlorinated hydrocarbons,
dyes, agrochemicals, bleaching of cotton pulp and accidental leakage in store tanks and
pipelines release chlorine into the environment. An effective method to reduce air pollution is
to increase the green over. Plantation of trees especially broad leaved plants, ornamental trees
and afforestation helps these plants absorb various pollutants, gases and dust on their leaves,
twigs and stems and help avoiding pollution. Thus there is a need for development of
methods for the synthesis of chemicals without involving pollution.

Over the years different principles have been proposed to design, developand
implement processes for synthesis of chemical products. Green chemistryprinciples enable
scientists and engineers to protect and benefit the economy, people and the planet by finding
creative and innovative ways to reduce waste, conserve energy, and discover replacements for
hazardous substances.

Green chemistry is defined as “the design of chemical products and processes that
reduce or eliminate the use and generation of hazardous substances. Green chemistry can also
be defined through the use of metrics. While a unified set of metrics has not been established,
many ways to quantify greener processes and products have been proposed. These metrics
include ones for mass, energy, hazardous substance reduction or elimination, and life cycle
environmental impacts. It’s important to note that the scope of these of green chemistry and
engineering principles go beyond concerns over hazards from chemical toxicity and include
energy conservation, waste reduction, and life cycle considerations such as the use of more
sustainable or renewable feedstock and designing for end of life or the final disposition of the
product.
Twelve Principles of Green Chemistry

Basics of green chemistry include any chemical process or technology which

improves the environment and our quality of life. It is a special contribution of the chemists
to the condition for sustainable development. In this direction, Paul Anastas and John Warner
have formulated guideline or blueprint for practicing green chemistry that is expected to
make a greener chemical, process or product which in turn help to save the environment.
These principles are given below.

1. Prevention: It is better to prevent waste than to treat or clean up waste after it has
been created.
The first principle aims to develop the zero waste technology (ZWT). In terms of
ZWT, in a chemical synthesis, waste product should be zero or minimum. It also aims to
use the waste product of one system as the raw material for other systems. As for example,
bottom ash of thermal power station can be as a raw material for cement and brick
industry; effluent coming out from cleaning of machinery parts may be used as coolant
water in thermal power station; municipal waste as a source of energy; etc.. Many such
examples are known. Such practices will reduce the waste product.
2. Atom Economy: Synthetic methods should be designed to maximize the
incorporation of all materials used in the process into the final product.
The concept of atom economy has been illustrated in unit-III.
3. Less Hazardous Chemical Syntheses: Wherever practicable, synthetic methods
should be designed to use and generate substances that possess little or no toxicity to
human health and the environment.
This principle aims to develop the methodologies that will minimize the use and
formation of toxic and hazardous. In other words, the synthetic methodologies should use
and generate the eco-friendly substance that will show title or no toxicity to human health
and environment.
4. Designing Safer Chemicals: Chemical products should be designed to affect their
desired function while minimizing their toxicity.
In many chemical industries, not only the waste product but the starting materials are
also quite hazardous to the workers and environment. For example, adipic acid,is widely
used in polymer industries (cf. manufacture of nylon, polyurethane, lubricants, etc.
Benzene is the starting material for the synthesis of adipic acid but benzene is
carcinogenic and benzene being a VOC pollutes air. In green technology developed by
Drath and Frost, adipic acid is enzymatically synthesized from glucose.
5. Safer Solvents and Auxiliaries: The use of auxiliary substances (e.g., solvents,
separation agents, etc.) should be made unnecessary wherever possible and innocuous
when used.
This principle aims to use green solvents (e.g. water, supercrictical CO 2 in place of
volatile halogenated organic solvents e.g. CH2Cl2, CHCl3, C2Cl4 (perchloroethlene), CCl4
for chemical synthesis and other purpose. If possible solvent free synthesisis preferred. For
example, Claisen rearrangement can be carried out in solid phase (Scheme 1.)

Scheme 1. Claisen rearrangement in solid phase

6. Design for Energy Efficiency: Energy requirements of chemical processes should be
recognized for their environmental and economic impacts and should be minimized. If
possible, synthetic methods should be conducted at ambient temperature and pressure.
To save energy, synthetic methodologies should need more and more moderate
conditions and the amibient temperature and pressure are the best choice. It need suitable
catalysts (i,e. enzyme) can work at the ambient conditions.
Energy savings can be done in many others ways: Refluxing requires conditions
requires less energy ; waste heat may be used for heating the reactants and other things;
improving the technology of heating system; preference for photochemical reactions
(specially by using the solar radiation) instead of thermochemical reactions; extraction of
energy from the waste product, use of microwave heating etc.
These practices advocate the concept of green energy as demanded by the 6th principle.
7. Use of Renewable Feedstock: A raw material or feedstock should be renewable
rather than depleting whenever technically and economically practicable.
It encourages the use of starting material (i,e. raw material or feedstock) which should
be renewable, if technically and economically practicable. In fact, continuous use (i,e.
overexploitation) of the nonrenewable (e.g. petroleum product, fossil fuel) will deplete the
resource and future generation will be deprived. Moreover, use of these nonrenewable
resources puts a burden on the environment.
 On the other hand, use of sustainable or renewable resources e.g. agricultural or
biological product ensures the sharing of resources by future generation. Moreover,this
practice generally does not put much burden on the environment.The products and wastes
are generally biodegradable.
The practice of this principles has been illustrated in many cases like bioplastics and
biopolymers(e.g. PHB, PHV, PHVB, BIOPOL, etc.) biodiesel, carbon monoxide feedstock
in the manufacture of polycarbonate, green synthesis of furfural from biomas, green
synthesis of adipic acid and catechol, polylactic acid from biomas.
8. Reduce Derivatives: Unnecessary derivatization (use of blocking groups, protection/
deprotection, temporary modification of physical/chemical processes) should be
minimized or avoided if possible, because such steps require additional reagents and can
generate waste.
Specially in organic synthesis, we need very often protection of some functional
group. Finally, we again need their deprotection. It is illustrated in the following example
of synthesis of m-hydroxybenzoic acid from m-hydroxybenzaldehyde (Scheme 2).

Scheme 2. Green synthesis of m-hydroxybenzoic acid from m-hydroxybenzaldehyde

Obviously, in such cases, atom economy is also less. The green chemistry principle
aims to develop the methodology where unnecessary steps should be avoided, if
practicable. Bio catalytic reactions very often need no protection of selective group.
9. Catalysis: Catalytic reagents (as selective as possible) are superior to stoichiometric
reagents.
This principle of green chemistry states that catalytic reagents are superior to
stoichiometric reagents. The use of catalysts is preferred because of following advantages.
(i)100% atom economy because the true are fully recovered without any change in their
chemical and physical properties.
(ii) The catalyzed reactions are faster i,e. energy save is possible.
(iii) Reaction yield are better.
(iv) Selective reaction product.
(v) Maximum utilization of the starting material and minimum production of the waste
material.
Some representative catalytic reactions(100% atom economy) are:

10. Design for Degradation: Chemical products should be designed so that at the end of
their function they break down into innocuous degradation products and do not persist in
the environment.
It states that the waste product should degrade automatically to clean the environment.
Thus the biodegradable polymers and pesticide are always preferred. Sometimes, the
polymers are to be made degradable photochemically. Here it should be mentioned that
the degraded products should not be toxic.
11. Real-time analysis for Pollution Prevention-Analytical methodologies need to be
further developed to allow for real-time, in-process monitoring and control prior to the
formation of hazardous substances.
Analytical methodologies should be developed or modified, so that continuous
monitoring of the manufacturing and processing units is possible, This is very much
important for the chemical industries and nuclear reactors. This efficient monitoring is
quite essential to avoid the accident.
12. Inherently Safer Chemistry for Accident Prevention-Substances and the form of a
substance used in a chemical process should be chosen to minimize the potential for
chemical accidents, including releases, explosions, and fires.
The substance to be used in a chemical industries should be in such forms so that the
possibility of accidents can be minimized. For example, if the chemical process works
with the gaseous substances, then the possibility of accidents including explosion is
relatively higher compared to the system working with the nonvolatile liquid and solid
substance. In fact, the risk is minimum if the process works with solid substances at every
step.
 Chemists from all over the world are using their creative and innovative skills to
develop new processes, synthetic methods, reaction conditions, catalysts etc., using the green
chemistry concepts. Some examples are given below.

1. Hydrochlorofluorocarbons (HFCs): Historically, chlorofluorocarbons (CFCs) have

been used as refrigerants in air conditioners and refrigerators. CFCS have the advantages
of safe combustibility, high stability, and low toxicity, but unfortunately they destroy the
ozone layer.HFCs have replaced CFCs and HFCs are, indeed, safer for the ozone layer.

2. Converting waste glycerin from biodiesel production to propylene glycol with the use
of a copper-chromate catalyst. Propylene glycol produced in this way will be cheap
enough to replace the more toxic ethylene glycol that is the primary ingredient in
automobile antifreeze.

3. Another approach towards protecting plants from pests and diseases is to activate their
natural defense mechanism against pests and diseases it is known as Harpin technology.
Harpin is a naturally occurring protein that is isolated from genetically altered bacteria.
When applied to the leaves and stems of plants, this protein elicits their natural defense
systems. The EPA has classified harpin as Category IV, which is reserved for the materials
with the lowest hazard potential. As an added benefit, Harpin also stimulates plant growth.

4. In order to decrease human consumption of petroleum, chemists have investigated

methods for producing polymers from renewable resources such as biomass. Polylactic
acid (PLA) is a polymer of naturally occurring lactic acid (LA), and LA can be produced
from the fermentation of corn. Another advantage of polylactic acid is that, unlike most
synthetic polymers which liter the landscape and pack landfills, it is biodegradable.PLA
can also be recycled by conversion back to lactic acid. It can replace many petroleum-
based polymers in products such as carpets, bags, cups and textile fibres.

Tools of Green Chemistry

The list of tools to help companies to change to safer products and processes is
growing rapidly, and it can sometimes be challenging to know which among the many
available options will prove the most useful. Tools vary in several ways, the most important
being that different tools are used to accomplish different ends. A hazard assessment is not
the same as an alternatives assessment, although a hazard assessment is often a part of an
alternatives assessment. An alternative assessment is not the same as a lifecycle analysis
(LCA), and a resource analysis is another different approach. The objective of this section is
to provide a way to review some of the well-known and proven tools in a more coherent
manner by organizing them into different categories.

The difficult task for chemists and others is to create new products, processes and
services that achieve the societal, cheap and environmental boons that are now required in
organic synthesis. For organic synthesis the challenges for chemists include the discovery and
development of new synthetic pathways using green chemistry tools such as alternative
starting materials, reagents, catalysts, solvents and processes. The details of each tool is
discussed below.

Alternative starting materials

Many chemical industries producing organic chemical depend on petroleum feedstock.

In fact, use of biotechnology involving biological feedstock, biocatalysts and biosynthesis is
the most important aspect of green chemistry in chemical industries.The remarkable
advantages in bio transformations are: ambient reaction conditions i.e. normal temperature
and pressure, aqueous media, use of renewable feedstock. Here we shall give some examples.

Green reagents

In order to carry out the transformation of selected feedstock into the target molecule
the criteria of efficiency, availability and effect of the green reagent used is important. The
success of modern organic synthesis mostly relies upon the selection and implementation of
proper reagents, which may be either used under specific or variety of conditions.
These reagents are to target the conversion of a specific functional group without affecting
the other, a challenging task, and to give higher yields as far as possible. A good reagent must
give least problems while working up the reaction. The qualities of a good reagent suitable
for modern organic synthesis are:

 The reagent should be cheap.

 It should be eco-friendly i.e., poses less risk to the environment and could be recycled
whenever required.
 It should be versatile i.e., works under variety of conditions.
 The reagent may require to target specific functional group.
 It should give a good yield of the desired product.
 The workup conditions must be less tedious.
 Examples of some green reagents are dimethyl carbonate, polymer supported reagents
and light.

Dimethyl carbonate (DMC) is produced through a green catalytic process by Enichen (Italy).
Low toxicity, the absence of irritating or mutagenic effects associated with it and its
biodegradability qualifies DMC as an environmentally friendly chemical. It is used as a
benign substitute for hazardous and toxic reagents such as dimethyl sulphate, methyl iodide
and phosgene. In fact, in the presence of a nucleophile and under basic conditions DMC
exhibits a versatile and tunable chemical reactivity, depending up on the experimental
conditions. In particular, at the reflux temperature (900 oC), it can react as a methoxy
carbonylating agent and at T> 1200 oC it acts as methylating reagent. Both reactions generate
methanol as by-product that can be recycled for the same product of DMC. DMC avoids the
formation of unwanted inorganic salts and the related disposal.

Organic waste management:

Oxidation of organic compounds is very often required in both organic synthesis and
treatment of waste present in the effluents of organic chemical industries. For these oxidation
reactions,very often metal complexes are used as catalysts and the process produces a big
burden on the environment. For this purpose, green technology considers the application of
lactase enzyme which can oxidize many organic compounds in aqueous media by simply
using atmospheric oxygen at ambident conditions.

Adipic acid and catechol synthesis

Scheme 3. Green synthesis adipic acid and catechol

 The conventional manufacture of the chemical products like adipic acid (used in
production of nylon polymer), catechol, BHT, etc. needs the consumption of petroleum based
feedstock like benzene, toluene, etc. Based on green chemistry an alternative process has
been developed (Scheme 3).

This technique consumes the agro-based product as the feedstock and the biocatalyst
is the genetically altered E.coli. The variety producing catechol is different from the species
leading to adipic acid.

Chitin (a biopolymer) can be easily obtained from the shells of crabs and other sea-
products.It can be processed into the modified polymers that find many applications
including the oil-drilling industry, biomedical industry, waste management industry, etc.

Green Catalysts

It is not only the “green” solvents that will change the face of synthetic organic
reactions, but also the use of “green catalysts” will improve substantially the efficiency of
many industrial processes. The use of catalysts is one of the principles of Green Chemistry.
Catalysis is considered as a cornerstone for innovative changes in chemical processes.
Catalysts helps to save energy, minimize reaction time, increase yield, reduce use of solvents,
and lower production of by-products and waste. Catalysis with “green” catalysts(which can
be recycled) is considered a very important step in the direction of Green Chemistry for many
industrial processes.
Catalytic systems based on immobilized metal complexes have been reported which
are capable of catalyzing reactions of pharmaceutical value, such as the selective oxidation of
steroidal compounds. In one study, chloroauric acid (HAuCl4) is used as a catalyst in water
for the stereoselective, cycloisomerization of various functionalized allenes to five or six
membered oxygen or nitrogen containing heterocycles. Compared to traditional gold catalysts
in organic solvents, this catalytic system is more environmentally friendly and can be reused
after complete conversion of the substrate.
An economical and sustainable transfer hydrogenation for aldehydes and ketones is a
chemo-selective procedure which uses neither precious/non-precious metals nor ligands.
Wacker oxidation of higher alkenes and aryl alkenes has been developed using molecular
oxygen as the oxidant, in which colloidal palladium nanoparticles stabilized in ethylene
carbonate are considered to facilitate its reoxidation under co-catalyst free conditions. A
simplified one-step procedure for making some mesoporous solid sulfonic acids has been
reported and can achieve environmentally friendly replacements for traditional acids such as
sulfuric acid and its organic derivatives.
Invention of clay-supported zinc chloride (clayzic) is the basis of a commercial
“Envirocat”, catalyst, which has proven to be useful for Lewis acid catalyzed reactions,
including benzylations, olefinations, and some cyclizations. A new solid Lewis acid, HMS-
supported zinc triflate has shown reasonable selectivity in the rearrangement of α-pinene
oxide to campholenic aldehyde with excellent reusability compared to conventional
homogeneous processes.
Zeolites, popular green catalysts, are crystalline alumino-silicates with exchangeable
cations. A major application of the zeolites in catalysis is in acid catalyzed reactions such as
alkylation, acylation, electrophilic aromatic substitution, cyclization, isomerization and
condensation,. A convenient and rapid method for Knoevenagel condensation has been
developed by using 1,4-Diazabicyclo-[2.2.2]-octane-base ionic liquid catalysts. These
catalysts can be recycled seven times without activity loss.

Green solvents

The replacement of toxic or hazardous organic solvents in industrial processes and

systems has been initiated long time ago. Examples, like replacement of benzene with
toluene, cyclohexane instead of carbon tetrachloride, dichloromethane instead of chloroform
etc. The scientific literature contains many examples and practices with replacement of the
most toxic and hazardous solvents.

Green solvents are environmentally friendly solvents or bio-solvents, which are

derived from the processing of agricultural crops. The uses of petrochemical solvents are the
key to the majority of chemical processes but not without severe implications on the
environment. The Montreal protocol identified the need to re-evaluate chemical processes
with regard to use of volatile organic compounds (VOCs) and its impact theses the
environment. Green solvents were developed as environmentally friendly alternative to
petrochemical solvents. Ethyl lactate, an ester of lactic acid is a green solvent derived from
processing corn. Lactate esters solvents are commonly used solvents in the paints and
coatings industry and have numerous attractive advantages including being 100%
biodegradable, easy to recycle, non-corrosive, non-carcinogenic and non-ozone depleting.
Ethyl lactate is a particularly attractive solvent for the coatings industry as a result of its high
solvency power, high boiling point, low vapour pressure and low surface tension. It is a
desirable coating for wood, polystyrene and metals and also acts as a very effective paint
stripper and graffiti remover. Ethyl lactate has replaced solvents including NMP, toluene,
acetone and xylene, which has resulted in the workplace being made a great deal safer. Other
applications of ethyl lactate include being an excellent cleaner for the polyurethane
industry. Ethyl lactate has a high solvency power which means it has the ability to dissolve a
wide range of polyurethane resins. The excellent cleaning power of ethyl lactate also means
it can be used to clean a variety of metal surfaces, efficiently removing greases, oils,
adhesives and solid fuels. The use of ethyl lactate is highly variable as it has eliminated the
use of chlorinated solvents.

The major part of the undesirable solvents have a good alternative in the group of the
“green” solvents; for example dichloromethane (which is yet a recommended alternative to
other chlorinated solvents) can be replaced by ethyl acetate or t-butyl methyl ether (MTBE).
The dipolar aprotic solvents group (dimethylformamide, N-methylpyrrolidinone) is the only
group of unwanted solvents which has non-satisfactory alternative of replacement, because of
their unique solvating properties.

1. Preferred Usable Undesirable

2. Sc-CO2 Cyclohexane Pentane
3. ILs Heptane Hexane(s)
4. Water Toluene Di isopropyl ether
5. Acetone Methyl cyclohexane Diethyl ether
6. Ethanol Isooctane Dichloromethane
7. 2-propanol Acetonitrile Dichloroethane
8. 1-propanol 2- THF MeTHF Chloroform
9. Ethylacetate Xylenes Pyridine
10. Isopropylacetate DMSO Dioxane
11. Methanol Acetic acid Dimethoxyethane
12. 1-Butanol Ethylene glycol Benzene
13. tert-Butyl alcohol Methyl Ethyl Ketone Carbon tetrachloride
Note: Sc-CO2 is referred to Supercritical-CO2.

The five main solvent systems which are currently considered as “green” are: i)
solventless systems, ii) water, iii) ionic liquids, iv) fluorous solvents and v) supercritical
fluids. Even though the last couple of decades has seen a large development of all of these
systems as “clean” alternatives for synthesis and catalysis, it is also becoming increasingly
clear that no single system will, in its own right, ever be able to replace completely all
conventional reagents and solvents as a truly environmentally friendly alternative. It means
that an ideal and universal “green” solvent for all situations does not exist because there are
drawbacks associated with all of these systems, both from the point of views of applicability
and sustainability.
Organic Synthesis in Water
Although water is considered a problem for organic synthesis and the purification
processes and drying in final products is very cumbersome, in recent years water is
considered a good solvent for organic reactions. A good example is the synthetic routes of the
Diels-Alder reactions in which the hydrophobic properties of some reagents makes water an
ideal solvent. Water as a solvent accelerates some reactions because some reagents are not
soluble and provides selectivity. The low solubility of oxygen is also an advantage for some
reactions where metal catalysts are used. When aryl aldehyde reacts with nitroacetonitrile in
heterogeneous aqueous medium at room temperature for 7 hr., α-cyano-β-aryl-nitro ethane
results in high yield (Scheme 4).

Scheme 4. Green Synthesis of α-cyano-β-aryl-nitro ethane

The product yield in the above case is 90%, when phenyl group is replaced by p-
Cl-C6H4, the yield of the product is 95%. With p-OH- C 6H4replacing C6H5 the yield of the
product becomes 94%.

Green processes with suitable examples.

Green synthesis of ibuprofen

Ibuprofen is a widely used non steroidal anti-inflammatory drug (NSAID) and inhibits
the enzyme. Its commercial synthesis was first introduced by Boots company of Nottingham,
UK with atom economy only 40% (Scheme 5). It involves six lengthy steps consisting of
Fridel-Crafts acylation of 4-isobutyl benzene using stoichiometric quantity of Lewis acid,
Darzens glycidic ester condensation, elimination to get ketone, oxime formation, dehydration
to get nitrile and then its hydrolysis to get ibuprofen as the final product. The methodology
has been being used since 1960’s, but BHC has developed a new method with atom economy
77%.

Scheme 5. Boots synthesis of Ibuprofen with atom economy only 40%.

This modified and greener method involves Fridel-Crafts acylation of 4-isobutyl

benzene using HF acid, its reduction to get alcohol and CO insertion to get ibuprofen with
atom economy 77% (Scheme 6).

Scheme 6. BHC green synthesis of Ibuprofen with atom economy of 77%.

Thus the use of alternate regents such as HF acid for acylation reaction, palladium
catalyst in the CO insertion reaction gave rise to the greener method. For this contribution,
BHC was awarded Presidential Green Chemistry Award (PGCA) of the USA in 1997. The
development of this greener alternate method let the reduction of lot of waste products.

Example-2: Coenzyme catalysed benzoin condensation

Thiamine hydrochloride was used as the catalyst for the synthesis of benzoin through
benzoin condensation (Scheme 7).
 Conventional method
O
H O OH
NaCN
2
EtOH/H2O
Alternate Green method
O
H O
OH
Thaimine hydrochloride
2

Scheme 7. Thiamine hydrochloride mediated synthesis of benzoin.

Example 3: Synthesis of Adipic acid

Green and alternate route for the synthesis of adipic replacing traditional acid is
shown in scheme 8.

O OH
HNO3

or
O
Traditional route HO OH

O
Adipic Acid

Green route
KHSO4.Aliquid 336
Scheme 8. Conventional and green synthesis of adipic
Example 4: Greener method for the production of ally alcohol.
Traditional Route: Alkaline hydrolysis of allyl chlorie, which generate acid as a by-
product

Greener route: To avoid chlorine. Two stop reaction using propylene CH2=CHCH3

The added benefit of the greener route is recovery of acetic acid in the final step, leaving no
unwanted by product
Future of Green Chemistry

Though the tenets of green chemistry might seem simple to implement, improvements
can still be made in a large number of chemical processes. A lot of the chemical products we
all utilize come from processes that still fail to meet a number of these principles; plenty of
these products are still derived from chemicals from crude oil, and many still produce large
amounts of waste. There are, of course, challenges involved in meeting some of the principles
in a large number of processes, but it can also drive new research and the discovery of new
chemistry. It is to be hoped that, in the coming years, many more processes will be
adapted with these principles in mind. Microwave mediated and sonochemical organic
synthesis are important green synthetic methods used in organic synthesis, which are
described in Unit II and III respectively.