Leon María Elena Larissa Vanillin Information History of benzene Ring structure Functional groups Hückels rule Vanillin History of benzene The empirical formula for benzene had been long known but its highly unsaturated structure was a challenge to determine ID: 526378
Download Presentation The PPT/PDF document "Aromatic chemistry" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
Aromatic chemistry
LeonMaríaElenaLarissa
VanillinSlide2
Information
History of benzene
Ring structure
Functional groups
Hückel’s
rule
VanillinSlide3
History of benzene
The empirical formula for benzene had been long known, but its highly unsaturated structure was a challenge to determine. Archibald Scott Couper in 1858 and Joseph Loschmidt in 1861 suggested possible structures that contained multiple double bonds or multiple rings, but the study of aromatic compounds was in its earliest years, and too little evidence was then
available to help chemists decide on any particular structure.
In 1865, the German chemist Friedrich August
Kekulé
published
a
paper in French suggesting that the structure contained a ring
of six carbon atoms with alternating single and double bonds
BACK
TestSlide4
History of benzene
Who was the first person to suggest the ring structure for benzene?
Archibald Scott Cooper
Joseph Loschmidt
Friedich August Kekulé
Erich
HükelSlide5
History of benzene
Benzene has a/an ______ structure.
Saturated
Unsaturated
Strong
WeakSlide6
Ring Structure
The most commonly encountered aromatic compound is benzene. The usual structural representation for benzene is a six carbon ring (represented by a hexagon) which includes three double bonds. Each of the carbons represented by a corner is also bonded to one other atom. In benzene itself, these atoms are hydrogens.
The double bonds are separated by single bonds so we recognize the arrangement as involving conjugated double bonds. An alternative symbol uses a circle inside the hexagon to represent the six
π electrons
. Each of these symbols has good and bad features.
BACK
TestSlide7
Ring structure
How much carbon does benzene have?
3
4
5
6Slide8
Ring structure
What kind of bonds does benzene have?Single, double
Double, triple
Single, double, triple
Single, tripleSlide9
Functional groups
In organic chemistry, functional groups are specific groups of atoms or bonds within molecules that are responsible for the characteristic chemical reactions of those molecules.
The atoms of functional groups are linked to each other and to the rest of the molecule by covalent bonds
.
Combining the names of functional groups with the names of the parent alkanes generates what is termed a systematic
nomenclature
for
naming organic
compounds.
BACK
TestSlide10
Functional groups
What do you have to follow if you want to name an organic compound?Plain Nomenclature
Normal organic names
Ordinary nomenclature
Systematic nomenclatureSlide11
Hückel’s rule
A cyclic ring molecule follows Hückel's rule when the number of its π-electrons equals
4n + 2 where "n" is zero or any positive integer, although clear cut
examples are really only established for values of n = 0 up to about n = 6
.
Aromatic compounds are more stable than theoretically predicted by alkene hydrogenation data; the "extra" stability is due to the delocalized cloud of electrons, called resonance energy.
BACK
TestSlide12
Hückel’s rule
BACK
What name is given to this formula: (4n+2)
Hückel
Cooper
Kekulé
AugustSlide13
Hückel’s rule
BACK
Following the previous formula (4n + 2) with n = 1, how much molecules does it have?
4
5
6
7Slide14
Vanillin
Vanillin is a phenolic aldehyde, which is an organic compound with the molecular formula C8H8O3.
Natural "vanilla extract" is a mixture of several hundred different compounds in addition to vanillin. Artificial vanilla
flavouring
is often a solution of pure vanillin, usually of synthetic origin. Because of the scarcity and expense of natural vanilla extract, synthetic preparation of its predominant component has long been of interest
.Slide15
Next questionSlide16
Next questionSlide17
Next questionSlide18
Next questionSlide19
Next questionSlide20
Next questionSlide21
Next questionSlide22
Next questionSlide23
I’m sorry, try again
BACKSlide24
I’m sorry, try again
BACKSlide25
I’m sorry, try again
BACKSlide26
I’m sorry, try again
BACKSlide27
I’m sorry, try again
BACKSlide28
I’m sorry, try again
BACKSlide29
I’m sorry, try again
BACKSlide30
I’m sorry, try again
BACKSlide31
I’m sorry, try again
BACK