Assignment Cover Sheet

Department of Biochemistry, BZU, Multan.

Assignment of Biochemistry.

NAME: Muhammad Zeeshan Ahmed.

_______________________________________________________

STUDENT ID: BS BC 14 17.

_______________________________________________________

ASSIGNMENT NAME: Organic Solvents,its properties and uses.

_______________________________________________________

DUE DATE: 25th of February, 2015.

Declaration

I certify that the attached work is entirely my own (or where submitted to meet the

requirements of an approved group assignment is the work of the group), except where

work quoted or paraphrased is acknowledged in the text. I also certify that it has not been

submitted for assessment in any other unit or course.

I agree that Deakin University may make and retain copies of this work for the purposes of

marking and review, and may submit this work to an external plagiarism-detection service

who may retain a copy for future plagiarism detection but will not release it or use it for any

other purpose.

DATE: 24th of February, 2015.

_______________________________________________________

An assignment will not be accepted for assessment if the declaration appearing above has

not been duly completed by the author.

Solvent A solvent is a substance that dissolves a solute (a chemically different liquid, solid or gas), resulting in

a solution. A solvent is usually a liquid but can also be a solid or a gas. The quantity of solute that can

dissolve in a specific volume of solvent varies with temperature. Common uses for organic solvents are

in dry cleaning(e.g., tetrachloroethylene), as paint thinners (e.g., toluene, turpentine), as nail polish

removers and glue solvents (acetone,methyl acetate, ethyl acetate), in spot removers (e.g., hexane,

petrol ether), in detergents (citrus terpenes) and in perfumes(ethanol). Solvents find various

applications in chemical, pharmaceutical, oil and gas industries, including in chemical syntheses and

purification processes.

Examples Water is the most commonly cited example of a solvent. Other common examples are hexane, ethanol,

and ether.

A solvent dissolves a solute, a good example would be sugar (the solute) and water (the solvent) mixing

together. A example of a solvent would be water, an example of a solute would be salt or sugar.

Examples: water, ethanol, methanol, iso-propanol, butanol, kerosene and many others.

Sometimes when one solvent is not useful then a mixture of two or more solvents is also used.

Organic Solvents

The most commonly used group of non-aqueous liquid solvents is the organic solvents. Organic

solvents are hydrocarbons and related substances - an organic compounds that contain carbon

atoms.

The majority of industrially used organic solvents are volatile (the vapour pressure is higher than

0,1 mbar at 20° C).

Chemical Nature of Organic Solvents Solvents usually have a low boiling point and evaporate easily or can be removed by distillation, thereby

leaving the dissolved substance behind. Solvents should therefore not react chemically with the

dissolved compounds - they have to be inert. Solvents can also be used to extract soluble compounds

from a mixture. Solvents are usually clear and colorless liquids and most of them have a characteristic

smell. The concentration of a solution is the amount of compound that is dissolved in a certain volume

of solvent. The solubility is the maximal amount of compound that is soluble in a certain volume of

solvent at a specified temperature.

ORGANIC SOLVENT CLASSIFICATION Most organic solvents can be classified into chemical groups based on the configuration of the hydrogen

and carbon atoms and the presence of different functional groups . Chemical groups that are commonl y

used are straight or branched chains of carbon and hydrogen (eg. hexane, heptane), cyclic hydrocarbons

(eg. cyclohexane, turpentine), esters (ethyl acetate, i s o p r o p y l a c e t a t e ) , a r o m a t i c

hydrocarbons (eg. benzene, toluene, xylene), alcohols (eg. ethanol, isopropanol), ketones (eg. acetone,

methyl ethyl ketone), halogenated hydrocarbons (eg. carbon tetrachloride, c h l o r o f o r m ) , a l d e h y

d e s ( e g . acetaldehyde, formaldehyde), ethers (eg. diethyl ether, isopropyl ether), glycols (eg. ethylene

glycol, hexylene glycol) and nitro-hydrocarbons (eg. nitroethane, nitromethane).

Properties and Uses of Different Organic Solvents

1. HYDROCARBONS

i. Benzene

Physical Properties Formula: C6H6

IUPAC ID: Benzene

Density: 876.50 kg/m³

Boiling point: 80.1 °C

Molar mass: 78.11 g/mol

Melting point: 5.5 °C

Soluble in: Water

Structure of Benzene

Geometry of Benzene Benzene represents a special problem in that, to account for the bond lengths quantitatively, there must

either be electron delocalization (molecular orbital theory) or a spin coupling of the p-orbitals (valence

bond theory):[39]

The various representations of benzene

X-ray diffraction shows that all six carbon-carbon bonds in benzene are of the same length, at 140

picometres (pm). The C–C bond lengths are greater than a double bond (135 pm) but shorter than a

single bond (147 pm). This intermediate distance is consistent with electron delocalization: the electrons

for C–C bonding are distributed equally between each of the six carbon atoms. Benzene has 8 hydrogen

atoms fewer than the corresponding parent alkane, hexane. The molecule i s planar.[40] The MO

description involves the formation of three delocalized π orbitals spanning all six carbon atoms, while in

VB theory the aromatic properties of benzene originate from spin coupling of all six π orbitals.[41][42][43][44]

It is likely that this stability contributes to the peculiar molecular and chemical properties known as

aromaticity. To indicate the delocalized nature of the bonding, benzene is often depicted with a circle

inside a hexagonal arrangement of carbon atoms.

As is common in organic chemistry, the carbon atoms in the diagram above have been left unlabeled.

Realizing each carbon has 2p electrons, each carbon donates an electron into the delocalized ring above

and below the benzene ring. It is the side-on overlap of p-orbitals that produces the pi clouds.

Derivatives of benzene occur sufficiently often as a component of organic molecules that there is a

Unicode symbol in the Miscellaneous Technical block with the code U+232C (⌬) to represent it with three

double bonds,[45] and U+23E3 (⏣) for a delocalized version.[46]

Uses of Benzene as a solvent

Benzene was previously used widely as a solvent in labs, but this use has decreased in many

countries due to the concern over carcinogenic effects. Benzene is a naturally occurring

component of petroleum and is present in gasoline.

Individuals working in industries involved with benzene production (petrochemical industry,

coke manufacturing),rubber tire or cast rubber film manufacturing, transport or storage of

benzene or benzene-containing products, and gas station employees all are at risk for excess

benzene expose. Benzene has been removed from commercial solvents, the use of industrial

solvents may still be a source of exposure. Historically, benzene used as a solvent in printing

inks in the rotogravure industry and adhesives by shoemakers led to a high degree of exposure

in these industries.

Benzene is used mainly as an intermediate to make other chemicals, above all

ethylbenzene,cumene, cyclohexane, nitrobenzene, and alkylbenzene. More than half of the

entire benzene production is processed into ethylbenzene, a precursor to styrene, which is used

to make polymers and plastics like polystyrene and EPS. Some 20% of the benzene production is

used to manufacture cumene, which is needed to produce phenol and acetone for resins and

adhesives. Cyclohexane consumes ca. 10% of the world's benzene production; it is primarily

used in the manufacture of nylon fibers, which are processed into textiles and engineering

plastics. Smaller amounts of benzene are used to make some types of rubbers, lubricants, dyes,

detergents, drugs, explosives, and pesticides. In 2013, the biggest consumer country of benzene

was China, followed by the USA. Benzene production is currently expanded in the Middle East

and in Africa, whereas capacities in Western Europe and North America stagnate.

ii.Toluene

Physical properties Molecular weight 92g

Empirical formula C7H8

Boiling point (OC) 110.6 C

Freezing point (OC) -95 C

Specific gravity (20/4) 0.867

Structure of Toluene

Geometry of Toluene

Toluene, also known as methylbenzene, is an organic chemical compound. It is categorized as such

because of the presence of carbon (C) atoms in its chemical formula, C7H8. You may notice that the

chemical formula of toluene (C7H8), has seven carbon (C) atoms and eight hydrogen (H) atoms. This is

significant because it means that it is classified as a hydrocarbon, a compound that only contains carbon

(C) and hydrogen (H) atoms.

Additionally, toluene is considered an aromatic compound because a benzene ring is present in its

chemical structure. A benzene ring is present when there are six carbon (C) atoms that connect to one

another with alternating double bonds, creating a hexagonal 'ring'. In the case of toluene, the carbon

atoms are at each edge of the hexagon.

Because toluene is both an aromatic compound and a hydrocarbon, these name qualifiers may be

combined, making the compound an aromatic hydrocarbon. The chemical structure also shows that

there is a methyl group, which is -CH3 attached to the benzene ring, the reason why it is also called

methylbenzene.

To make it a little more clear, a picture of the chemical structure for toluene is just below. He re, it shows

that it contains a benzene ring (boxed in red):

Chemical Structure of Toluene

The following illustration shows two ways of drawing the structure of toluene; both are possibilities of

how the benzene ring can be illustrated. On the left, the benzene ring is shown as a hexagon that has

three double bonds, and on the right, the benzene ring is shown also as a hexagon, but with a circle

inside.

Two ways to Draw the Chemical Structure of Toluene

Uses of Toluene as a solvent

In organic chemical synthesis where it is used to make Benzene, Xylene and

Phenol

In the manufacture of explosives

In the manufacture of polymers for plastic bottles and to make Polyurethane

and Nylon

In the manufacture of cosmetics

In the manufacture of dyes and inks

As a fuel additive where it is used to increase the octane ratings

As a solvent in cleaning agents, adhesives, resins, paints and paint thinners

In the early years of the manufacture of Coca Cola beverages, Toluene was

used to remove the cocaine from the coca leaves before production

As Toluene has good heat transfer capabilities, it has been used in sodium cold

traps which are used in the nuclear industry

In the manufacture of jet fuel blends

2.Alcohol

i.Methanol

Physical properties Molecular weight 32g

Empirical formula CH4O

Boiling point (OC) 64C

Freezing point (OC) -98C

Specific gravity (20/4) 0.792

Structure of Methanol

Source of Methanol Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical

with formula CH3OH (often abbreviated MeOH). It is the simplest alcohol, and is a light, volatile,

colorless, flammable, liquid with a distinctive odor that is very similar to but slightly sweeter than

ethanol (drinking alcohol). At room temperature it is a polar liquid.

Methanol is produced naturally in the anaerobic metabolism of many varieties of bacteria, and is

ubiquitous in the environment. As a result, there is a small fraction of methanol vapor in the

atmosphere. Over the course of several days, atmospheric methanol is oxidized with the help of sunlight

to carbon dioxide and water.

Methanol burns in air forming carbon dioxide and water:

2 CH3OH + 3 O2 → 2 CO2 + 4 H2O

A methanol flame is almost colorless in bright sunlight.

Methanol is often called wood alcohol because it was once produced chiefly as a byproduct of the

destructive distillation of wood. Most methanol today is produced from the methane found in natural

gas, but methanol is also produced from all types of biomass, coal, waste, and even CO 2 pollution from

power plants. Learn more about methanol production here.

Methanol is a colorless liquid that boils at 64.96° C (148.93° F) and solidifies at -93.9° C (-137° F). It forms

explosive mixtures with air and burns with a non-luminous flame. Methanol is also a toxin and should

not be ingested – drinking quantities of methanol can result in blindness and severe damage to the

central nervous system. For more information on methanol and health, please visit our Health & Safety

section.

Uses of Methanol as a solvent The largest use of methanol by far is in making other chemicals. About 40% of methanol is

converted to formaldehyde, and from there into products as diverse as plastics, plywood, paints,

explosives, and permanent press textiles.

Other chemical derivatives of methanol include dimethyl ether, which has replaced

chlorofluorocarbons as an aerosol spray propellant, and acetic acid. Dimethyl ether (DME) also

can be blended with liquified petroleum gas (LPG) for home heating and cooking, and can be

used as a diesel replacement for transportation fuel.

Methanol is used on a limited basis to fuel internal combustion engines. Pure methanol is

required by rule to be used in Champcars, Monster Trucks, USAC sprint cars (as well as midgets,

modifieds, etc.), and other dirt track series, such as World of Outlaws, and Motorcycle

Speedway.

Methanol is a traditional denaturant for ethanol, the product being known as "denatured

alcohol" or "methylated spirit". This was commonly used during the Prohibition to discourage

consumption of bootlegged liquor, and ended up causing several deaths.[23]

Methanol is also used as a solvent, and as an antifreeze in pipelines and windshield washer fluid.

In some wastewater treatment plants, a small amount of methanol is added to wastewater to

provide a carbon food source for the denitrifying bacteria, which convert nitrates to nitrogen to

reduce the nitrification of sensitive aquifers.

ii.Ethanol

Physical properties Molecular weight 46g

Empirical formula C2H6O

Boiling point (OC) 78 C

Freezing point (OC) -114 C

Specific gravity (20/4) 0.789

Structure of Ethanol

Source of Ethanol Commonly referred to simply as alcohol or spirits, ethanol /ˈɛθənɒl/ is also called ethyl alcohol, and

drinking alcohol. It is the principal type of alcohol found in alcoholic beverages, produced by the

fermentation of sugars by yeasts. It is a neurotoxic[8][9] psychoactive drug and one of the oldest

recreational drugs used by humans. It can cause alcohol intoxication when consumed in sufficient

quantity. Ethanol is used as a solvent, an antiseptic, a fuel and the active fluid in modern (post-mercury)

thermometers (since it has a low freezing point) . It is a volatile, flammable, colorless liquid with a strong

chemical odor.

Effects on the central nervous system Ethanol is a central nervous system depressant and has significant psychoactive effects in sublethal

doses; for specifics, see "Effects of alcohol on the body by dose". Based on its abilities to change the

human consciousness, ethanol is considered a psychoactive drug.[30] Death from ethanol consumption is

possible when blood alcohol level reaches 0.4%. A blood level of 0.5% or more is commonly fatal. Levels

of even less than 0.1% can cause intoxication, with unconsciousness often occurring at 0.3–0.4%.

Uses of Ethanol as a solvent Ethanol is used extensively as a solvent in the manufacture of varnishes and perfumes;

as a preservative for biological specimens;

in the preparation of essences and flavorings;

in many medicines and drugs;

as a disinfectant and in tinctures (e.g., tincture of iodine);

as a fuel and gasoline additive (see gasohol).

Many automobiles manufactured since 1998 have been equipped to enable them to run on

either gasoline or E85, a mixture of 85% ethanol and 15% gasoline. E85, however, is not yet

widely available.

Denatured, or industrial, alcohol is ethanol to which poisonous or nauseating substances have

been added to prevent its use as a beverage; a beverage tax is not charged on such alcohol, so

its cost is quite low.

Medically, ethanol is a soporific, i.e., sleep-producing; although it is less toxic than the other

alcohols, death usually occurs if the concentration of ethanol in the bloodstream exceeds about

5%. Behavioral changes, impairment of vision, or unconsciousness occur at lower

concentrations.

3. Chlorinated solvents

i. Chloroform

Physical properties Molecular weight 119g

Empirical formula CHCI3

Boiling point (OC) 61C

Freezing point (OC) -23C

Specific gravity (20/4) 1.48

Structure of Chloroform

Nature of Chloroform Chloroform is an organic compound with formula CHCl3. It is one of the four chloromethanes.[2] The

colorless, sweet-smelling, dense liquid is a trihalomethane, and is considered hazardous. Several million

tons are produced annually as a precursor to PTFE and refrigerants, but its use for refrigerants is being

phased out.[2] The hydrogen attached to carbon in chloroform participates in hydrogen bonding.

Uses of chloroform as a solvent Chloroform is primarily used in the production of refrigerants (e.g. chlorofluorocarbon (CFC)-22,

fluorocarbon-22), in the production of plastics (especially vinyl chloride) and in the manufacture

of other chemicals.

Chloroform is used as an extraction solvent for fats, oils, greases, rubber, waxes, gutta-percha,

resins, lacquers, floor polishes, artificial silk manufacture, gums and adhesives.

It is utilised as an industrial solvent in the extraction and purification of some antibiotics,

alkaloids, vitamins and flavours.

It is used as a solvent in organic chemistry, in photography and in making dyes, drugs and

pesticides.

Other uses are as a dry cleaning agent to remove spots, as a fumigant and in fire extinguishers

to lower the freezing temperature of carbon tetrachloride.

Chloroform formulated with other ingredients is used to control screw worm in animals.

Chloroform is steadily being replaced by less toxic solvents and may no longer be used in some

of these applications.

Its use as an inhaled anaesthetic during surgery has already been largely discontinued.

ii. Carbon tetrachloride

Physical properties Molecular weight 154

Empirical formula ClCI4

8oiling point (OC) 76

Freezing point (OC) -23

Specific gravity (20/4) 1.58

Structure of Carbon tetrachloride

Nature of Carbon Tetrachloride Carbon tetrachloride, also known by many other names (the most notable being tetrachloromethane

(also recognized by the IUPAC), carbon tet in the cleaning industry, Halon-104 in firefighting and

Refrigerant-10 in HVACR), is the inorganic compound with the chemical formula CCl4. It was formerly

widely used in fire extinguishers, as a precursor to refrigerants, and as a cleaning agent. It is a colourless

liquid with a "sweet" smell that can be detected at low levels.

In the carbon tetrachloride molecule, four chlorine atoms are positioned symmetrically as corners in a

tetrahedral configuration joined to a central carbon atom by single covalent bonds. Because of this

symmetrical geometry, CCl4 is non-polar. Methane gas has the same structure, making carbon

tetrachloride a halomethane. As a solvent, it is well suited to dissolving other non-polar compounds,

fats, and oils. It can also dissolve iodine. It is somewhat volatile, giving off vapors with a smell

characteristic of other chlorinated solvents, somewhat similar to the tetrachloroethylene smell

reminiscent of dry cleaners' shops.

Uses of Carbon tetrachloride as a solvent Washing Nuclear Magnetic Resonance NMR tubes

Acetone (followed by adequate drying).

Removal of grease from NMR tubes Trichloroethylene, Chloroform.

Organic synthesis (Eg: feedstock use of CTC for

synthesis of DV acid chloride)

Dichloromethane; Chloroform

Solvent of polymers

Tetrahydrofuran; Chloroform;

Dichloromethane & Dichloroethane

4. Ketones

i. Acetone

Physical properties Molecular weight 58

Empirical formula C3H60l

Boiling point (OC) 56

Freezing point (OC) -95

Specific gravity (20/4) 0.790

Structure of Acetone

Nature of Acetone Acetone is the organic compound with the formula (CH3)2CO. It is a colorless, volatile, flammable liquid,

and is the simplest ketone.

Acetone is miscible with water and serves as an important solvent in its own right, typically for cleaning

purposes in the laboratory. About 6.7 million tonnes were produced worldwide in 2010, mainly for use

as a solvent and production of methyl methacrylate and bisphenol A.[11][12] It is a common building block

in organic chemistry. Familiar household uses of acetone are as the active ingredient in nail polish

remover and as paint thinner.

Uses of Acetone as a solvent Acetone is a good solvent for most plastics and synthetic fibres including those used in Nalgene

bottles made of polystyrene, polycarbonate and some types of polypropylene.

It is ideal for thinning fiberglass resin, cleaning fiberglass tools and dissolving two-part epoxies

and superglue before hardening.

It is used as a volatile component of some paints and varnishes.

As a heavy-duty degreaser, it is useful in the preparation of metal prior to painting; it also thins

polyester resins, vinyl and adhesives.

Many millions of kilograms of acetone are consumed in the production of the solvents methyl

isobutyl alcohol and methyl isobutyl ketone. These products arise via an initial aldol

condensation to give diacetone alcohol.[2]

2 (CH3)2CO → (CH3)2C(OH)CH2C(O)CH3

Acetone is used as a solvent by the pharmaceutical industry and as a denaturation agent in

denatured alcohol.Acetone is also present as an excipient in some pharmaceutical products.[5]

Laboratory uses In the laboratory, acetone is used as a polar aprotic solvent in a variety of organic reactions,

such as SN2 reactions.

The use of acetone solvent is also critical for the Jones oxidation.

It is a common solvent for rinsing laboratory glassware because of its low cost, volatility, and

ability to dissolve water. For similar reasons, acetone is also used as a drying agent.

Acetone can be cooled with dry ice to -78 °C without freezing;

Acetone/dry ice baths are commonly used to conduct reactions at low temperatures.

Acetone is fluorescent under ultraviolet light, and acetone vapor may be used as a fluorescent

tracer in fluid flow experiment.

6. Miscellaneous solvents

i. Acetic Acid

Physical properties Molecular weight 60

Empirical formula C2H4O2

Boiling point (OC) 118

Freezing point (OC) + 17

Specific gravity (20/4) 1.051

Structure of Acetic Acid

Nature of Acetic Acid Acetic acid is an organic compound with the chemical formula CH3COOH (also written as CH3CO2H or

C2H4O2). It is a colourless liquid that when undiluted is also called glacial acetic acid. Vinegar is roughly

3 %-9 % acetic acid by volume, making acetic acid the main component of vinegar apart from water.

Acetic acid has a distinctive sour taste and pungent smell. Besides its production as household vinegar, it

is mainly produced as a precursor to polyvinylacetate and cellulose acetate. Although it is classified as a

weak acid, concentrated acetic acid is corrosive and can attack the skin.

Uses of Acetic acid as a solvent Glacial acetic acid is an excellent polar protic solvent. It is frequently used as a solvent

for recrystallization to purify organic compounds.

Acetic acid is used as a solvent in the production of terephthalic acid (TPA), the raw material

forpolyethylene terephthalate (PET). About 20% of acetic acid was used for TPA production.

Acetic acid is often used as a solvent for reactions involving carbocations, such as Friedel-

Crafts alkylation. For example, one stage in the commercial manufacture of

synthetic camphor involves a Wagner-Meerwein rearrangement of camphene to isobornyl

acetate; here acetic acid acts both as a solvent and as a nucleophile to trap

the rearranged carbocation.

Glacial acetic acid is used in analytical chemistry for the estimation of weakly alkaline

substances such as organic amides. Glacial acetic acid is a much weaker base than water,

so the amide behaves as a strong base in this medium. It then can be titrated using a

solution in glacial acetic acid of a very strong acid, such as perchloric acid.[55]

Reference;

Website, http://en.wikipedia.org/wiki

Website,http://technical.information/properties.of.solvents.aspx

Website,http://mgc-a.com/products/uses.html