Download - Introduction of organic chemistry
Introduction to Organic Chemistry
Introduction to Organic chemistry
1.1 Chemistry of carbon1.2 Types of organic compound
1.3 Applications of organic compound
INTRODUCTION TO ORGANIC CHEMISTRY
Organic chemistry is a chemistry of carbon compounds. Example : methane, DNA, urea, DDT (insecticide), penicillin , nicotine, aspirin etc..
But not all carbon compounds are organics. Example :
carbonate (CO32-; cyanide (CN-), bicarbonate (HCO3
-), carbon dioxide and carbon monoxide.
Organic chemistry is the study of compounds that contain carbon. It is one of the major branches of chemistry.
The history of organic chemistry can be traced back to ancient times when medicine for human extracted from plants and animals to treat members of their tribes.
In ancient era, it was produced willow bark which was used as a pain killer, (willow bark contains acetylsalicylic acid, the ingredient in aspirin )- Organic Chemistry.
Organic chemistry was first defined as a branch of modern science in the early 1800's by Jon Jacob Berzelius. He classified chemical compounds into two main groups:
i. Organic: if they originated in living or once-living matter, and
ii). Inorganic: if they came from "mineral" or non-living matter.
In 1828, Frederich Wöhler discovered that urea - an organic compound - could be made by heating ammonium cyanate (an inorganic compound).
Wöhler mixed silver cyanate and ammonium chloride to produce solid silver chloride and aqueous ammonium cyanate:
He then separated the mixture by filtration and tried to purify the aqueous ammonium cyanate by evaporating the water.
Chemistry of Carbon
The carbon family, Group 14 in the p-block, contains carbon (C), silicon (Si), germanium (Ge), tin (Sn), lead (Pb), and flerovium (Fl). Each of these elements has only two electrons in its outermost p orbital: each has the electron configuration ns2np2.
Catenation is the linkage of atoms of the same element into longer chains. Catenation occurs most readily in carbon, which forms covalent bonds with other
carbon atoms to form longer chains and structures. Catenation is the reason for the presence of the vast number of organic compounds
in nature.
1. Carbon-carbon bonds are strong, long chains or rings of carbon atoms bonded to one another are possible.
2. Diamond and graphite are two familiar examples: a. Diamond lattice being a three-dimensional network of carbon atoms, b.Graphite more closely resembles a planar network.
3.Carbon is not unique in forming bonds to itself because other elements such as boron, silicon, and phosphorus form strong bonds in the elementary state. But with the combination of hydrogen carbon affords a remarkable variety of carbon hydrides (Hydrocarbons)
4. Carbon forms bonds not only with itself and with hydrogen but also with many other elements, including strongly electron-attracting elements
WHY ORGANIC CHEMISTRY SPECIAL?
TYPES OF ORGANIC COMPOUNDS
Organic compound: An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. Such as carbides, carbonates, simple oxides of carbon (such as CO and CO2), etc.
There are three generally accepted sources of organic compounds:
SOURCES OF ORGANIC COMPOUNDS
2. Living organismsoThe chemical compounds of living things are known as organic compounds because of their association with organisms and because they are carbon-containing compounds. oAmong the numerous types of organic compounds, four major categories are found in all living things: carbohydrates, lipids, proteins, and nucleic acids3. Invention/Human ingenuityoAntibiotics, aspirin, vanilla flavoring, and heart drugs are examples of substances that no longer have to be obtained directly from nature, they are manufactured in laboratories from organic starting materials. oEach year over 250,000 new chemical compounds are discovered and many of these are products of scientists' imaginations, exploration.o Plastics are excellent examples of substances that are the product of invention - they are not found anywhere in nature.
1. carbonized organic matter: o Carbonization is the term for the conversion of an organic
substance into carbon or a carbon-containing residue through pyrolysis or destructive distillation.
o Example: the generation of coal gas and coal tar from raw coal. Fossil fuels from vegetable matter, coal to produce coke. the charcoal making process, etc.
Property Organic compound Inorganic compound
Bonding with molecule Usually covalent Often ionic
Forces between molecules
Generally weak(Intermolecular force)
Quite strong(Electrostatic force)
Normal physical state
Gases, liquids or low-melting-point solids
Usually high-melting-point solids
Flammability Often flammable Usually non-flammable
Solubility in water Insoluble SolubleConductivity Non-conductor Conductor
Rate of chemical reaction Slow and complex Fast and simple
Properties of typical organic and inorganic compound
Name Of OrganicCompounds
Origin Usage
ProteinsExample :a) Enzymesb) Hormones
From animals a) As a structural materialsb) As a biological catalyst and regulators
Fats and OilsExample :a) Triglyceride b) Paraffin Oils c) Almond Oils
From animals and vegetables
To store energy
VitaminsExample :A, B Complex, C, D, E and K
From food For healthy growth and functioning
Naturally Occurred Organic Compounds
Items Examples Usage
Plastics Poly (ethene), Perspex.
For packaging, plastic bags, as a substitute for glass.
Medicines andDrugs
Tranquilizer, Analgesic and Bactericide.
To treat tropical diseases such as Trypanosomiasis or Sleeping Illness and Malaria.
Pesticides Dichlorodiphenyl trichloroethane( DDT )
To kill houseflies and other insects.
Dyes Methylene blue Give colour to the material.
Synthetic Organic Compounds
Type of organic compoundHomocyclic organic compound.docx
Hetero-cyclic organic compound.docx
Homocyclic-aromatic organic compound.docx
Hetero-aromatic organic compound.docx
Saturated
Unsaturated
Aromatic● CLOSE rings of Carbon atoms. ● Contain a benzene ring. Example: Benzene
Aliphatic● OPEN chains of Carbon atoms.● Unbranched or Branched ● Contain Single, Double or Triple bonds. Example: ethane (CH3–CH3) ethene / ethylene (CH2=CH2) ethyne / acetylene ( )
Alicyclic● CLOSE rings of Carbon Atoms. ● Rings form the shape of POLYGON (triangle, square, rectangle or etc). Example: Epoxide
CC CCOO
HH
HHHH
HH
HH
HH
HCHC CHCH
Functional groups: an atom or group of atoms which determine the chemical and physical properties of an organic compound.
Functional Groups
IMPORTANCEIMPORTANCE
All the member of a particular homologous series have:
1. Same general formula eg : CnH2n+1OH 2. Same functional group : same chemical reactions. Eg : all alcohols contain –OH group.
3. Each member differs from the next member by a constant –CH2.
4. As the molecular size increase, the boiling points increase.
HOMOLOGOUS SERIES
Alkane Nomenclature
Formula of organic compounds
● Molecular formula ● Empirical formula● Structural formula● Condensed formula● Bond-line formula
Organic compounds can be complexA system is needed that shows structure. We want something that is easy to read.
Example: Glucose, C6H12O6
C6H12O6
Molecular formulaCH2O
Empirical formula
Empirical formulaSimplest ratio number of atoms of each element in a molecule.
Molecular formula :Actual number of atoms of each element in a molecule.
Structural Formula: Shows all atoms in the bonds, Bonds are represented as line
Condensed Formula: Shorthand way of writing Molecular formula
Bond-line formulaRepresent structure between carbon-carbon bonds.Atoms other than carbon and hydrogen are called heteroatoms.
CHCH33CHCH22CHCH22CHCH3 3 is shown asis shown as
CHCH33CHCH22CHCH22CHCH22OHOH is shown asis shown as
Isomers
Structural isomers Stereoisomers
Isomers are different compounds that have the same molecular formula.
Classification of isomers
n-pentane 2-methylbutane
2,2-dimethylpropane
Structural isomers
C5H12
Example
CHCH33CHCH22CHCH22CHCH22CHCH22CHCH33
n-hexanen-hexane
C6H14
(CH(CH33CHCH22))22CHCHCHCH33
3-Methylpentane3-Methylpentane
(CH(CH33))22CHCH(CHCHCH(CH33))22
2,3-Dimethylbutane2,3-Dimethylbutane(CH(CH33))33CCHCCH22CHCH33
2,2-Dimethylbutane2,2-Dimethylbutane
(CH(CH33CHCH22))22CHCHCHCH33
2-Methylpentane2-Methylpentane
Stereoisomer
Compound with the same molecular formula and structural formula but with different arrangement of their bond in space.
HH33CC
CC CC
CHCH33
HH
HHHH
CHCH33
CC CC
HH33CC
HH
cis-2-butene trans-2-butene
cis (large groups on same side)
trans (large groups on opposite sides)
Naming of organic compound according to IUPAC system1 Identify the longest carbon chain. This chain is called the parent chain
2 Identify all of the substituents (groups appending from the parent chain).
3 Number the carbons of the parent chain from the end that gives the substituents the lowest numbers. When comparing a series of numbers, the series that is the "lowest" is the one which contains the lowest number at the occasion of the first difference. If two or more side chains are in equivalent positions, assign the lowest number to the one which will come first in the name.
4 If the same substituent occurs more than once, the location of each point on which the substituent occurs is given. In addition, the number of times the substituent group occurs is indicated by a prefix (di, tri, tetra, etc.).
5 If there are two or more different substituents they are listed in alphabetical order using the base name (ignore the prefixes). The only prefix which is used when putting the substituents in alphabetical order is iso as in isopropyl or isobutyl. The prefixes sec- and tert- are not used in determining alphabetical order except when compared with each other.
6 If chains of equal length are competing for selection as the parent chain, then the choice goes in series to: A. the chain which has the greatest number of side chains. B. the chain whose substituents have the lowest- numbers. C. the chain having the greatest number of carbon atoms in the smaller side chain. D. the chain having the least branched side chains.
7 A cyclic (ring) hydrocarbon is designated by the prefix cyclo-which appears directly in front of the base name.
prefix Length of Carbon
Meth 1
Eth 2
Prop 3
But 4
Pent 5
Hex 6
Hept 7
Oct 8
Non 9
Dec 10
1. Longest chain is 6 - hexane2. Two methyl groups - dimethyl
3. Use 2,5-dimethylhexane
EXAMPLE
Types of Organic Reactions
General
Addition Substitution Elimination Rearrangement
Specific
Hydrogenation Esterification Oxidation Hydrolysis
Addition: Two substances react together to form a single substance.
Ethane Bromoethane
Substitution (SN2 reaction): An atom or a group (leaving group) in a
molecule is replaced by another atom or group (nucleophile / electrophile).
Elimination: Removal of atoms or groups of atoms from a saturated molecule to form an unsaturated molecule.
Rearrangement: Migration of an atom, a group of atoms or a bond from one atom to another within molecule to form its isomer.
Hydrogenation•Addition of hydrogen to a multiple bond to form a single bond substance.
+ H—H+ H—HCC CC HH CC CC
HH HH
HH HH
HH
HH
HH
HH
HH
Pt
Ethylene Ethane
Hydrogen
Hydrogenation of alkane
Esterification: Acid-catalyzed ester formation between alcohol and carboxylic acid.
CHCH33COCHCOCH22CHCH33
OO
++ HH22OOCHCH33COHCOH
OO
++ CHCH33CHCH22OHOHHH22SOSO44
refluxEthanoic acid Ethanol Ethyl ethanoate
Fischer esterification
Oxidation: An increase in the number of bonds between carbon and oxygen and/or a decrease in the number of carbon-hydrogen bonds.
Hydrolysis•Chemical process in which a molecule is split into two parts by the addition of a molecule of water.
(CH3)3C–Br + H2O (CH(CH33))33C–OH + HBrC–OH + HBr
tert-Butyl alcohol alcoholtert-Butyl bromide Hydrogen bromide
Applications of Organic Compounds