1 introduction of organic chemistry. 2 syllabus introduction of organic chemistry classification ...
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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,Alccohols) 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 BondingTypes of Bonding
Ionic bonding– electron is fully transferred from metal to non-
metal– binding is by electrostatic attraction.
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Ionic BondingIonic Bonding
Na F
Sodium Atom Fluorine Atom
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Ionic Bonding (2)Ionic Bonding (2)
Na F
Attraction between the two ions is electrostatic -- Ionic Bond
Sodium ion Fluoride ion
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A SIMPLE COVALENT A SIMPLE COVALENT BONDBOND
H . H.
A pair of electrons is shared between the two bonded atoms.
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A SIMPLE COVALENT A SIMPLE COVALENT BONDBOND
H H
Bonded pair
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A LEWIS DIAGRAMA LEWIS DIAGRAM
H O H....
H O H. .... ...
COVALENT BONDS
CONSTRUCTEDFROM LEWISDOT SYMBOLS
(note use of lines for bonds)
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DRAWING CONVENTIONSDRAWING CONVENTIONS1. A shared pair (bond) is drawn as a line.
2. An unshared pair is shown as a pair of dots.
C O
N :3. The diagram includes formal charges (later).
H O H
H
.. +
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Carbon 4 bondsNitrogen (phosphorus) 3 bondsOxygen (sulfur) 2 bondsHalogen (F, Cl, Br, I) 1 bondHydrogen 1 bond
Bonding patterns
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Normal bonding patternsNormal bonding patternsNormal bonding patternsNormal bonding patterns
Carbon (4 bonds) C C C C
Nitrogen (3 bonds) N
(Phosphorus)
N N
Oxygen (2 bonds)
(Sulfur)
O O
Halogen (1 bond) X
(F, Cl, Br, I)
Hydrogen (1 bond) H
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Common Bonding Patterns -- Common Bonding Patterns -- CationsCations
..
..
:
+ + +
++
+ +
+
C N O
N O
N O
N
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Common Bonding Patterns Common Bonding Patterns -- Anions-- Anions
.. ....
..
..
..
..:
__ _
_
_
B C N O
N
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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
Aliphaticalkanes – contain only single bonds (saturated)alkenes – contain at least one double bond
(unsaturated)alkynes – contain at least one triple bond
Aromaticcontain a benzene ring
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Hydrocarbons Alkanes contain only single ( ) bonds and have the
generic molecular formula: [CnH2n+2]
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 trigonal planar with sp2 hybridized orbitals.There is no rotation about the C=C bond in alkenes.
Each C atom is tetrahedral with sp3 hybridized orbitals. They only have single bonds.
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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 C=C 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 AlkanesNaming AlkanesCC11 - C - C10 10 : the number of C atoms present in the chain.
Each member CC33 - C - C1010 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 IsomersConstitutional 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.
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.
Classes of Organic CompoundsClasses of Organic Compounds
Alkane Alkyl Halide Alcohol
Ether Amine
Alkene Aldehyde Ketone
Carboxylic Acid Ester Amide
Alkyne Nitrile
R H R X R OH
R O R' R NH2
C C
R
R
R
R
R C H
O
R C R'
O
R C
O
OH R C O
O
R' R C NH2
O
C CR R' C NR
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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
CH2=CH2 → CH3CH2OH Hydrolysis of Esters
CH3COOC2H5 → CH3COOH + C2H5OH Reduction of Aldehyde/Ketone
CHO/C=O → 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
DehydrationC2H5OH → CH2=CH2 + H2O
Oxidation of Alcohol(K2Cr2O7/H2SO4)1-alcohol → Aldehyde → Acid
Reduction of Alcohols(Red P )C2H5OH + 2HI → CH3CH3+H2O + I2
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METHANOL
Ethanol (ethyl alcohol) or grain alcohol a. Made f rom the fermentation of grain, f ruit, or sugar b. C6H12O6 + yeast 2C2H5OH + CO2 c. The alcohol that is in beverages d. Added to automotive fuels – 10% as gasohal e. 1 pint of pure alcohol will kill most people f . caused deterioration of the liver, memory loss
and is harmful to unborn babies
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ETHANOL
HC C OH
H
H
H
H
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ISOPROPYL ALCOHOL
CC C
OH
HH
H
H
H
HH
I sopropyl alcohol (rubbing alcohol) a. Alcohol used for cuts and cleaning b. Will not be absorbed by the skin c. Toxic if taken internally d. Sold as a 70% solution – 140 proof
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Ethylene glycol a. Used f or antif reeze in cars b. Very sweet tasting c. Toxic – caused kidney failure and death
C C
HH
HH
OH OH
Liver C C
OH OH
OOKidney CaC2O4
Oxalic acid Calcium Oxalate
C C
HH
HH
OH OH
Ethylene glycol
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GLYCEROL
Glycerol a. Used in lotion to keep skin soft b. Food additive that keeps cookies soft c. Can add to nitric acid to form nitroglycerin
Nitroglycerin (nitro) taken to relieve angina heart pain
C C C
HH
OHOH
HHH
OH
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Carbonyl CompoundsIf an oxygen atom is attached to carbon by a double bondthe functional group –C=O is called carbonyl group.
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ALDEHYDE
R C H
O
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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 C=O 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 AmineCH3CHO + H2NOH CH3CH=N-OH + H2O
With Hydrazine (Phenyl Hydrazine)CH3CHO + H2NNH2 CH3CH=NNH2 + H2O
OxidationCH3CHO CH3COOH
Reduction (Pt / Ni)
CH3CHO + H2 CH3CH2OH
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FORMALDEHYDE
Formaldehyde a. Soluble in water b. 40% solution is called formaline c. Used in some plastic manufacturing d. Makes a good disinfectant
CH H
O
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BENZALDEHYDE
Benzaldehydea. called synthetic oil of almondb. used as flavoring – maraschino cherriesc. used in perfumes
CH
O
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Ketones
C
O
R R
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ACETONE
A c e t o n ea . M a d e f r o m I s o p r o p y l a l c o h o l
b . U s e d a s a s o l v e n t f o r f a t s , r u b b e r , p l a s t i c s , a n d v a r n i s h e sc . U s e d a s f i n g e r n a i l p o l i s h r e m o v e rd . W i l l n o t m i x w i t h w a t e rW a s h e s w a t e r o f f o f g la s s w a r e a f t e r c le a n in g
C
O
CH 3 C H 3CH 3 C H C H 3
O H - H
C
O
CH3 CH3
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CARBOXYLIC ACID
C
O
R OH R COOH
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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 PropertiesReaction with alkaliesR-COOH + NaOH R-COONa + H2ODecarboxylationCH3COOH + NaOH soda lime CH3COONa + H2O
CH3COONa + NaOH sodalime CH4 + Na2CO3
ReductionR-COOH LiAlH4/ 2H2 R-CH2OHReaction with CarbonatesR-COOH + Na2CO3 R-COONa + H2O + CO2
Dehydration2R-COOH R-COOCOCH3 + H2O Acid Anhydride
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FORMIC ACID
Formic Acida. Irritant to skinb. Part of the venom in ants, bee’s, or wasps
C
O
H OH
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ACETIC ACID
The acid in vinegar
C
O
CH3 OH
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BENZOIC ACID
Benzoic acidUsed to make benzene type compounds in organic synthesis
C
O
OH
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ESTERS
R C
O
O R
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O
O
Apricot (pentyl buterate)
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O
O
Orange (Octyl acetate)
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OC
O
CH3 Jasmine (benzyl acetate)
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OH
C
O
O CH3 Wintergreen (methyl salicylate)
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ETHER
R O R
Diethyl ether a. Used as a solvent b. Used for thinning paints c. Boils at 36 C (dries quickly) d. Used as anesthetic or as a drug e. Dissolves organic compounds readily f. Reacts with oxygen to form unstable peroxides
O
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DIETHYL ETHER
Tert-butyl ether (MTBE)a. Gasoline additiveb. Reduces CO emissionsc. Replaced lead as the antiknock compound
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TERT-BUTYL ETHER
CH3 O C
CH3
CH3
CH3
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ETHYLENE OXIDE
Ethylene Oxidea. Very toxic gasb. Used in the formation of ethylene glycolc. Ethylene glycol is used in antifreeze and in polyester fibers.
CC
O
H
H
H
H
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AMINES
N H
H
H
N H
H
R
N R
H
R
N R
R
R
primary
secondary
tertiary
amonia
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CH2 N H
H
CH2 Amphetamine (stimulant drug)
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Analine (used in dyes)N H
H
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N CH3
H
CH3
Dimethyl amineused in volcanizing rubber, tanning hydesand making of soaps
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N CH2CH3
CH2CH3
CH3CH2
Triethyl amineattracts insectswarning agent in natural gas