Introduction of Organic Chemistry

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Introduction of Organic Chemistry
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Syllabus

• Introduction of Organic chemistry
• Classification
• Sources
• Types
• Functional Groups (Aldehydes,Ketone,Acids,Alccohol
  s)
• Application

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Chemistry

• Chemistry is the study of the substances,
  specially their structure, properties,
  transformations and the energy changes
  accompanying these transformation.

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Branches

• Organic Chemistry
• Inorganic Chemistry
• Physical Chemistry

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Discipline Branches of Chemistry

• Analytical Chemistry
• Industrial Chemistry
• Instrumental Chemistry
• Agriculture Chemistry
• Medicinal Chemistry

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Organic Chemistry

• The study of Carbon Compounds or better to say
  the chemistry of hydrocarbons and their
  derivatives.

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ATOMIC STRUCTURE

• Atom Smallest indivisible particle of an element
• Molecule Smallest particle of matter

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Types of Bonding

• Ionic bonding
• electron is fully transferred from metal to
  non-metal
• binding is by electrostatic attraction.

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Ionic Bonding
Sodium Atom
Fluorine Atom
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Ionic Bonding (2)
Sodium ion
Fluoride ion
Attraction between the two ions is electrostatic
-- Ionic Bond
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A SIMPLE COVALENT BOND
A pair of electrons is shared between the two
bonded atoms.
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A SIMPLE COVALENT BOND
Bonded pair
H
H
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A LEWIS DIAGRAM
..
(note use of lines for bonds)
H
O
H
..
COVALENT BONDS
CONSTRUCTED FROM LEWIS DOT SYMBOLS
..
.
.
.
.
H O H
..
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DRAWING CONVENTIONS
1. A shared pair (bond) is drawn as a line.
C O
2. An unshared pair is shown as a pair of dots.
N
3. The diagram includes formal charges (later).
..

H O H
H
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Bonding patterns

• Carbon 4 bonds
• Nitrogen (phosphorus) 3 bonds
• Oxygen (sulfur) 2 bonds
• Halogen (F, Cl, Br, I) 1 bond
• Hydrogen 1 bond

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Normal bonding patterns
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Common Bonding Patterns -- Cations
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Common Bonding Patterns -- Anions
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Types of Carbons

• Primary (1) attached to only one other carbon
• Secondary (2) attached to two other carbons
• Tertiary (3) attached to three other carbons
• Quaternary (4) attached to four other carbons

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Hydrocarbons

• Aliphatic
• alkanes contain only single bonds (saturated)
• alkenes contain at least one double bond
• (unsaturated)
• alkynes contain at least one triple bond
• Aromatic
• contain a benzene ring

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Hydrocarbons

• Alkanes contain only single (? ) bonds and have
  the generic molecular formula CnH2n2
• Alkenes also contain double (? ?) bonds and
  have the generic molecular formula CnH2n
• Alkynes contain triple (? 2?) bonds and have
  the generic molecular formula CnH2n-2
• Aromatics are planar, ring structures with
  alternating single and double bonds eg. C6H6

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Types of Hydrocarbons
Each C atom is tetrahedral with sp3 hybridized
orbitals. They only have single bonds.
Each C atom is trigonal planar with sp2
hybridized orbitals. There is no rotation about
the CC bond in alkenes.
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Types of Hydrocarbons
Each C atom is linear with sp hybridized orbitals.
Each C--C bond is the same length shorter than a
C-C bond longer than a CC bond. The concept of
resonance is used to explain this phenomena.
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Alkanes

• 1 meth methane CH4
• 2 eth ethane C2H6
• 3 prop propane C3H8
• 4 but butane C4H10
• 5 pent pentane C5H12
• 6 hex hexane C6H14
• 7 hept heptane C7H16
• 8 oct octane C8H18
• 9 non nonane C9H20
• 10 dec decane C10H22

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Naming Alkanes C1 - C10 the number of C atoms
present in the chain.
- - - -

Each member C3 - C10 differs by one CH2 unit.
This is called a homologous series. Methane to
butane are gases at normal pressures. Pentane to
decane are liquids at normal pressures.
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Nomenclature of Alkyl Substituents
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Constitutional Isomers

• Substances which have the same molecular formula
  but a different structural formula.
• Isomers differ in connectivity.

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• A compound can have more than one name, but a
• name must unambiguously specify only one
  compound

A C7H16 compound can be any one of the following
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Functional Groups

• An atom or group of atoms which makes an organic
  compound reactive and decides its functions
  (properties) is called a Functional group.
• In an organic compound, the alkyl group
  determines the physical properties whereas the
  functional group determines the chemical
  properties of the compound.
• A Functional group can be introduced by
  displacing hydrogen of the hydrocarbon.
• The functional groups are directly attached to
  the carbon of the organic compound.

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• The basic structure of testosterone (male
  hormone) and estradiol (female hormone) is
  identical.
• Both are steroids with four fused carbon rings,
  but they differ in the functional groups attached
  to the rings.
• These then interact with different targets in the
  body.

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• 6 functional groups, all hydrophilic
• In a hydroxyl group (-OH), a hydrogen atom forms
  a polar covalent bond with an oxygen which forms
  a polar covalent bond to the carbon skeleton.
• Because of these polar covalent bonds hydroxyl
  groups improve the water solubility of organic
  molecules.
• Organic compounds with hydroxyl groups are
  alcohols and their names typically end in -ol.

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• A carbonyl group (-CO) consists of an oxygen atom
  joined to the carbon skeleton by a double bond.
• If the carbonyl group is on the end of the
  skeleton, the compound is an aldelhyde.
• If not, then the compound is a ketone.
• Isomers with aldehydes versus ketones have
  different properties.

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• A carboxyl group (-COOH) consists of a carbon
  atom with a double bond with an oxygen atom and a
  single bond to a hydroxyl group.
• Compounds with carboxyl groups are carboxylic
  acids.
• A carboxyl group acts as an acid because the
  combined electro-negativities of the two adjacent
  oxygen atoms increase the dissociation of
  hydrogen as an ion (H).

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• An amino group (-NH2) consists of a nitrogen atom
  attached to two hydrogen atoms and the carbon
  skeleton.
• Organic compounds with amino groups are amines.
• The amino group acts as a base because amino
  groups can pick up a hydrogen ion (H) from the
  solution.
• Amino acids, the building blocks of proteins,
  have amino and carboxyl groups.

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• A sulfhydryl group (-SH) consists of a sulfur
  atom bonded to a hydrogen atom and to the
  backbone.
• This group resembles a hydroxyl group in shape.
• Organic molecules with sulfhydryl groups are
  thiols.
• Sulfhydryl groups help stabilize the structure of
  proteins.

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• A phosphate group (-OPO32-) consists of
  phosphorus bound to four oxygen atoms (three with
  single bonds and one with a double bond).
• A phosphate group connects to the carbon backbone
  via one of its oxygen atoms.
• Phosphate groups are anions with two negative
  charges as two hydrogens have dissociated from
  the oxygen atoms.
• One function of phosphate groups is to transfer
  energy between organic molecules.

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Functional Groups
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Functional Groups
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Classes of Organic Compounds
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ALCOHOL FUNCTIONAL GROUP

• R O H

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Classification

• Monohydric Alcohols
• Polyhydric Alcohols
• - Dihydric Alcohols (Ethylene Glycol)
• - Trihydric Alcohols (Glycerol)

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Monohydric Alcohols

• Devided in Primary, Secondary and tertiary
  alcohols.
• CH3OH, CH3CH2OH
• Methanol Ethanol
• CH3CH(OH)CH3
• Isopropyl Alcohol
• CH3C(OH)(CH3)
• t-Butyl Alcohol

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Physical Properties

• Lower are colorless, neutral substances with
  characteristic sweet alcoholic smell and burning
  taste. Higher are waxy solids.
• Lower are readily soluble in water organic
  solvents but it decreases as M.W. increases.
• B.P. are higher than corresponding alkanes. e.g.
  Methanol-338 K and Methane-112K

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Preparation of Alcohol

• By Hydrolysis
• R-X NaOH? R-OH NaX
• By Hydration
• CH2CH2 ? CH3CH2OH
• Hydrolysis of Esters
• CH3COOC2H5 ? CH3COOH C2H5OH
• Reduction of Aldehyde/Ketone
• CHO/CO ? 1-Alcohol/2-alcohol
• Grignard Reagent
• R-Mg-X ?R-O-MgX ?R-OH

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Chemical properties

• Displacement of OH gr. By Halogen(X)
• R-OH HX ? RX H2O
• Action of Alkali Metals
• 2ROH 2Na ? 2RONa H2
• Dehydration
• C2H5OH ? CH2CH2 H2O
• Oxidation of Alcohol(K2Cr2O7/H2SO4)
• 1-alcohol ? Aldehyde ? Acid
• Reduction of Alcohols(Red P )
• C2H5OH 2HI ? CH3CH3H2O I2

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METHANOL
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ETHANOL
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ISOPROPYL ALCOHOL
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Ethylene glycol
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GLYCEROL
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Carbonyl Compounds

• If an oxygen atom is attached to carbon by a
  double bond
• the functional group CO is called carbonyl
  group.

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ALDEHYDE
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Physical Properties

• Formaldehyde is a gas at room temp. All other
  members are colorless liquids at ordinary temp.
  The higher members are solids.
• Lower aldehydes have unpleasant smell but as one
  goes up in the series the smell becomes more
  fruity. Ketones are generally pleasant smelling
  liquids.
• Solubilities
• Lower members are highly soluble in water.
  Solubilities decreases with increasing molecular
  mass.
• B.P. are higher than those of non polar alkanes.
• B.P. of aldehydes/Ketones are lower than the B.P.
  of alcohols.

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Chemical Properties

• Addition Across CO bond
• CH3CHO HCN CH3CH(CN)OH
  CH3CH(OH)COOH
• Acetaldehyde
  Cyanohydrins 2-hydroxy
  propanoicAcid -
• Addition of Grignard Reagent
• HCHO CH3MgBr HCH(OMgBr)CH3
  CH3CH2OH Mg(OH)Br
• With Hydroxyl Amine
• CH3CHO H2NOH
  CH3CHN-OH H2O
• With Hydrazine (Phenyl Hydrazine)
• CH3CHO H2NNH2
  CH3CHNNH2 H2O
• Oxidation
• CH3CHO
  CH3COOH
• Reduction (Pt / Ni)
• CH3CHO H2
  CH3CH2OH

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FORMALDEHYDE
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BENZALDEHYDE
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Ketones
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ACETONE
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CARBOXYLIC ACID
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Physical Properties

• The first nine mono carboxylic acids are
  colorless liquids, while the higher ones are
  colorless wax like solids.
• Solubility The first four (formic, acetic,
  propeonic, butiric) are soluble while fifth
  (valeric) is slightly soluble and acids above six
  carbon are insoluble in water.
• B.P. M.P. They have abnormally high b.p., even
  higher than those of alcohols of similar
  molecular weights.

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Chemical Properties

• Reaction with alkalies
• R-COOH NaOH R-COONa H2O
• Decarboxylation
• CH3COOH NaOH soda lime CH3COONa H2O
• CH3COONa NaOH sodalime CH4 Na2CO3
• Reduction
• R-COOH LiAlH4/ 2H2 R-CH2OH
• Reaction with Carbonates
• R-COOH Na2CO3 R-COONa
  H2O CO2
• Dehydration
• 2R-COOH R-COOCOCH3 H2O
• 
  Acid Anhydride

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FORMIC ACID
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ACETIC ACID
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BENZOIC ACID
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ESTERS
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ETHER
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DIETHYL ETHER
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TERT-BUTYL ETHER
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ETHYLENE OXIDE
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AMINES
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