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An organic compound is one that has carbonas the principal element
e
e
e ee
e
Carbon is unique
It has 6 electrons in its outer shell
arranges 1s2
2s2
sp2
It has room for 4 bonds to 4 other atoms.
Organic compounds have specific geometry
around the carbon to carbon bond
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The carbon atom forms bonds in atetrahedral structure with a bondangle of 109.5 O.
So a chain of carbon atoms makesa zigzag pattern
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Introduction
A hydrocarbon is a compoundconsisting of only hydrogen and
carbon.The carbon to carbon can be single,double, or triple bonds.
The bonds are always nonpolar
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Triple.
Double
Note that in each example, each carbonatom has four dashes, which represent four bonding pairs of electrons, satisfying theoctet rule.
Carbon-to-carbon bonds can be:
Single
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(B) branched
Carbon-to-carbon chains can be
(A) straight
(C) closed ring.
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Identify the longest continuous chain.
The locations or other groups of atoms attached to
the longest chain are identified and numbered bycounting from the end of the molecule which keepsthe numbering system as low as possible.
Hydrocarbon groups that are attached to the
longest continuous chain and named using theparent name and changing the ane suffix to yl
Naming alkanes
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Step-1 Identify the longest continuous chain Where is the longest continuous chain of carbons?
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EndingsEndings
Alkanes (all C-C single bonded parentAlkanes (all C-C single bonded parentchain) end inchain) end in ane ane MethMeth aneane CHCH 44
EthEth aneane CC 22HH66 PropProp aneane CC 33HH88
Attached carbon groups (substituents) endAttached carbon groups (substituents) end
inin yl yl MethMeth ylyl CHCH 33 -- EthEth ylyl CHCH 33CHCH 22 --
PropProp
ylyl
CHCH
33CHCH
22 CHCH
22
3-ethyl pentane
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Step 3. Name the attached groups.Step 3. Name the attached groups.
Carbon (alkCarbon (alk ylyl) groups) groups MethMeth ylyl CHCH 33 --
EthEth ylyl CHCH 33CHCH 22 -- PropProp ylyl CHCH 33CHCH 22 CHCH 22
HalogensHalogens Fluoro (F-)Fluoro (F-) Chloro (Cl-)Chloro (Cl-) Bromo (Br-)Bromo (Br-) Iodo (I-)Iodo (I-)
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Step 4. Designate where the groupStep 4. Designate where the groupis attached to the parent chain.is attached to the parent chain.
Use the numbers of the parent chain fromstep 2 to designate the location of theattached groups to the parent chain.
1 2 3 4 5
2-methyl
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Structural FormulasStructural Formulas
Lazy way to write the Hydrogens Instead of drawing the bonds, just state
how many hydrogens are attached NOTE: The bonds are between
CARBONS in a parent chain, and nothydrogens!
Lewis Structure
Structural Formula
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Order of PriorityOrder of Priority
IN A TIE, halogens get the lower number IN A TIE, halogens get the lower number before alkyl groupsbefore alkyl groups
4-chloro-2-methylpentane or 4-chloro-2-methylpentane or 2-chloro-4-methylpentane?2-chloro-4-methylpentane?
5 4 3 2 1
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Order of PriorityOrder of Priority
IN A TIE between SIMILAR GROUPS, theIN A TIE between SIMILAR GROUPS, thegroup lower ALPHABETICALLY gets thegroup lower ALPHABETICALLY gets thelower number lower number
4-bromo-2-chloropentane or 2-bromo-4-chloropentane ?
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IsomersIsomers
Straight chain alkanesStraight chain alkanes :: AnAnalkane that has all its carbonsalkane that has all its carbonsconnected in a row.connected in a row.
Branched chain alkanes:Branched chain alkanes: AnAn
alkane that has a branchingalkane that has a branchingconnection of carbons.connection of carbons.
Isomers: Compounds with same molecular formula butdifferent structures.
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Petroleumproductsand the
ranges of hydrocar-
bons in
eachproduct.
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There is only one possible wayThere is only one possible waythat the carbons in methane (CHthat the carbons in methane (CH 44),),ethane (Cethane (C 22HH66 ), and propane (C), and propane (C 33HH88))can be arranged.can be arranged.
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However, carbons in butane (CHowever, carbons in butane (C 44 HH1010 ) can) canbe arranged in two ways; four carbons in abe arranged in two ways; four carbons in arow (linear alkane) or a branchingrow (linear alkane) or a branching
(branched alkane). These two structures(branched alkane). These two structuresare two isomers for butane.are two isomers for butane.
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Different isomers are completely differentDifferent isomers are completely differentcompounds. They have different structures,compounds. They have different structures,different physical properties such as meltingdifferent physical properties such as melting
point and boiling point, and may have differentpoint and boiling point, and may have differentphysiological properties.physiological properties.
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Number of possible isomers increases
rapidly with the number of carbons C 30H62 >4 billion possible isomers
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Properties of Alkanes Main property: will burn
C C C
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Types of Carbon AtomsTypes of Carbon Atoms Primary carbon (1Primary carbon (1
oo
)) a carbon bonded toa carbon bonded to
one other carbonone other carbon
Secondary carbon (2Secondary carbon (2 oo )) a carbon bonded toa carbon bonded to
two other carbonstwo other carbons
Tertiary carbon (3Tertiary carbon (3 oo )) a carbon bonded toa carbon bonded to
three other carbonsthree other carbons
C
C
CH
H
H
C C
H
C
C
C
C
H
H
C C
H
HC
C
H
C
C
C
C
H
H
C C
H
H
C
C
C
H
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Unsaturated Hydrocarbons Can have more hydrogen atoms added Very important in biological systems Alkene: hydrocarbon that contains one
or more carbon-to-carbon doublebonds
To show the presence of the doublebond, the ane suffix from the alkanename is changed to ene.
General formula of C n Hn Simplest: ethylene, C 2H4
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Ethylene is the gas that ripens fruit, and a ripe fruitEthylene is the gas that ripens fruit, and a ripe fruitemits the gas, which will act on unripe fruit. Thus,emits the gas, which will act on unripe fruit. Thus,
a ripe tomato placed in a sealed bag with greena ripe tomato placed in a sealed bag with greentomatoes will help ripen them.tomatoes will help ripen them.
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Naming of Alkene is similar to naming alkanesexcept:
The longest continuous chain must containthe double bond.
The base name now ends in ene. The carbons are numbered so as to keep the
number for the double bond as low aspossible.
The base name is given a number whichidentifies the location of the double bond.
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Alkyne: hydrocarbon thatcontains one or more carbon-to-carbon triple bonds
Naming an alkyne is similar tothe alkenes, except the basename ends in yne.
General formula of C n H2n 2 Simplest: acetylene, C 2H2
Alkynes
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Properties of Alkenes and Alkynes
Similar physical properties to alkanes
Undergo more reactions than alkanes
Addition reaction: add compounds across doublebond
Importantly, they can form polymers
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Cyclic Hydrocarbons
Carbon atom chains in form of rings Can be represented by structural
formulas or symbolic representations
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Cycloalkanes and Aromatic Hydrocarbons Cycloalkanes are alkanes (only carbon to carbon
single bonds) which form a ring structure.
The "straight" chain has carbonatoms that are able to rotate freelyaround their single bonds,sometimes linking up in a closedring.
(B) Ring compounds of the firstfour cycloalkanes.
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An aromatic compound is one that is based on thebenzene ring( C 6H6).
Structure: Alternating single & Double Bonding
A benzene ring that is attached to another compound isgiven the name phenyl.
H
H
H
H
H
H
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Functional Groups
Group of atoms that gives a familyof organic compounds itscharacteristic chemical andphysical properties
Alkyl group: derived from alkane byremoving a H R stands for alkyl group in general
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Halogens (F 2, Cl 2, Br 2, I2,) can all add to ahydrocarbon to form am alkyl halide .
When naming the halogen the ine ending isreplaced by o
Fluorine becomes fluoro
Chlorine becomes chloro Bromine becomes bromo Iodine becomes iodo
Halogens
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Common examples of organic halides.
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Alcohol Family hydroxyl(OH) group
Replace - e with - ol CH 3OH, methanol, simplest
Produced industrially
Mainly a chemical intermediate
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C 2H5OH, ethanol
Made industrially and by fermentation
Industrially produced alcohol has noxioussubstances added
Small, simple alcohols tend to be toxic
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Multifunctional Alcohols
Several common alcohols have more than one OHgroup Ethylene glycol: main ingredient in antifreeze Glycerol: used in lotions
Ingredent in some explosives
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Ethers
Two alkyl groups attached to same O Example CH 3CH 2-O-CH 2CH 3
Used mainly as solvent Little chemical reactivity
Insoluble in water
Highly flammable
ld h d d
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Aldehydes and Ketones Both contain carbonyl group (C=O)
Aldehyde: R-CHO Ketone: R-CO-R
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Common Aldehydes Change - e ending to - al
Produced by oxidation of alcohols Formaldehyde used as a preservative
Larger ones used as fragrances Benzaldehyde flavor in maraschinocherries
C
O
H
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Common Ketones Change - e ending to - one
Acetone most common ketone Used primarily as a solvent
Produced by oxidation of alcohols
CH3
C
H3C
O
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Carboxylic Acid
Contains C=O and OH group on samecarbon Change - e to - oic acid
Acetic acid: acid in vinegar
R C
O H
O
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Esters
Derived from carboxylic acids andalcohols
Tend to be fragrant Methyl butyrate apple Ethyl butyrate pineapple Ethyl formate rum
Methyl salicylate wintergreen