Fuel System 2 Organic Chemistry faculty of

Fuel system

1. Organic Chemistry &
Hydrocarbons Groups
Prof. Dr. Eng. Medhat A. MOHAMMED Elkelawy
[email protected]
[email protected]

2. Organic Chemistry -
Introduction
•Organic chemistry is the study of carbon
compounds.
•Animals, plants, and other forms of life
consist of organic compounds.
–Nucleic acids, proteins, fats, carbohydrates,
enzymes, vitamins, and hormones are all
organic compounds.
•Biochemistry was developed later as the
study of the chemical compounds and
reactions in living cells.

3. Numbers and Types of Bonds for
Common Elements in Organic Compounds
Application of the octet rule indicates that these elements should bond as shown below:

4. Identifying Valid & Incorrect
Structural Formulas
An Example
Two structural formulas are shown above. Which on
does not represent a real compound?
•In structure (a) each H and halogen has one bond,
each C has four bonds, and each O has two bonds.
This is a valid structure.

5. Identifying Valid & Incorrect
Structural Formulas
An Example
As we examine (b), we note that each H has one bond,
each C has four bonds, the N has three bonds, BUT
the O has three bonds.
•The O should only have two bonds.
Therefore (b) is not a valid structure.

6. Identifying Incorrect Structural
Formulas
Confidence Exercise
•Check the number of bonds in the above figure
to each atom and determine whether any
bonding rules are violated.

7. Identifying Incorrect Structural
Formulas
Confidence Exercise
This is not a valid
structure for caffeine!
O should have
two bonds, C
should have 4
bonds
Each N should
have 3 bonds
Each C should
have 4 bonds

8. Hydrocarbons
•Hydrocarbons are the most simple organic
compounds.
•Hydrocarbons contain only carbon (C) and
hydrogen. (H)
•For classification purposes, all other organic
compounds are considered derivatives of
hydrocarbons.
•Hydrocarbons can be divided into aromatic
and aliphatic hydrocarbons.

9. Molecular Structure of Hydrocarbon:-
Carbon atoms form four bonds in molecular
structures, while hydrogen has one bond.
A saturated hydrocarbon molecule there is no
double or triple carbon-to-carbon bonds and will have a
maximum number of hydrogen atoms.

An unsaturated molecule will have double or triple
carbon-to-carbon bonds.

10. Division of the Family
of Hydrocarbons (functional group)
Classification of Hydrocarbons

11. Alkanes ( Paraffins )
•Alkanes are hydrocarbons that contain only
single bonds.
•Alkanes are said to be saturated hydrocarbons
–Their hydrogen content is at a maximum.
•Alkane general formula  C
n
H
2n + 2
•The names of alkanes all end in “-ane.”
•Methane  butane are gases
•Pentane  C
17
H
36
are liquids
•C
18H
38 and higher are solids

12. Alkanes – Energy Related
Products
•Methane = primary component of natural
gas
•Propane & Butane = primary component
of bottled gas
•Gasoline = pentane to decane
•Kerosene = alkanes with n = 10 to 16
•Alkanes with n > 16  diesel fuel, fuel
oil, petroleum jelly, paraffin wax,
lubricating oil, and asphalt

13. Visualization of an Alkane’s
Structure
Structural formula – a graphical
representation of the way atoms
are connected
Condensed structural formula –
save time/space and are
convenient
Ball-and-Stick models – 3D
models that can be built by
students

14. 14 | 14
Models of Three Alkanes
•Names, Structural Formulas, Condensed
Structural Formulas, and Ball-and-Stick Models

15. The First Eight Members of the
Alkane Series
All satisfy the general formula C
n
H
2n

+ 2

16. Introduction
•Recall that alkanes are aliphatic
hydrocarbons having C—C and C—H
bonds. They can be categorized as
acyclic.
•A cyclic alkanes have the molecular formula
C
n
H
2n+2
(where n = an integer) and contain only
linear and branched chains of carbon atoms.
They are also called saturated hydrocarbons
because they have the maximum number of
hydrogen atoms per carbon.
Alkanes

17. •Cycloalkanes:
Contain carbons joined in
one or more rings. Because their
general formula is C
n
H
2n
, they
have two fewer H atoms than an
acyclic alkane with the same
number of carbons.
Alkanes

18. 18
•All C atoms in an alkane are surrounded by four groups,
making them sp
3
hybridized and tetrahedral, and all bond
angles are 109.5°.
•The 3-D representations and ball-and-stick models for
these alkanes indicate the tetrahedral geometry around
each C atom.

Introduction

19. •The three-carbon alkane CH
3
CH
2
CH
3
,
called propane, has a molecular formula
C
3H
8. Note in the 3-D drawing that each C
atom has two bonds in the plane (solid
lines), one bond in front (on a wedge) and
one bond behind the plane (on a dashed
line).
Introduction

20. 20
•Additionally, in propane and higher molecular
weight alkanes, the carbon skeleton can be
drawn in a variety of ways and still represent
the same molecule. For example, the three
carbons of propane can be drawn in a
horizontal row or with a bend. These
representations are equivalent.
Introduction
Propane

21. 21
•There are two different ways to arrange four
carbons, giving two compounds with molecular
formula C
4
H
10
, named butane and isobutane.
•Butane and isobutane are isomers—two different
compounds with the same molecular formula.
Specifically, they are constitutional or structural
isomers.
•Constitutional isomers differ in the way the atoms
are connected to each other.

22. IF THE chain in the molecule are branched
with different molecular structures with the same
number of carbon and hydrogen atom is exist that
Known as “ISOMER”
Constitutional isomers

23. •Carbon atoms in alkanes and other organic
compounds are classified by the number of
other carbons directly bonded to them.
Introduction

24. •Hydrogen atoms are classified as primary
(1°), secondary (2°), or tertiary (3°)
depending on the type of carbon atom to
which they are bonded.
Introduction

25. Cycloalkanes
Cycloalkanes have molecular formula C
n
H
2n
and
contain carbon atoms arranged in a ring. Simple
cycloalkanes are named by adding the prefix
cyclo- to the name of the a cyclic alkane having
the same number of carbons.

26. 26
Nomenclature
The name of every organic molecule has 3 parts:
1.The parent name indicates the number of carbons in
the longest continuous chain.
2.The suffix indicates what functional group is
present.
3.The prefix tells us the identity, location, and number
of substituents attached to the carbon chain.

27. Find the parent carbon chain and add the suffix.
Note that it does not matter if the chain is straight or it
bends.

28. Also note that if there are two chains of equal
length, pick the chain with more substituents. In
the following example, two different chains in the
same alkane have seven C atoms. We circle the
longest continuous chain as shown in the
diagram on the left, since this results in the
greater number of substituents.

29. Number the atoms in the carbon
chain to give the first substituent the
lowest number.

30. If the first substituent is the same distance
from both ends, number the chain to give
the second substituent the lower number.

31. When numbering a carbon chain results in
the same numbers from either end of the
chain, assign the lower number
alphabetically to the first substituent.

32. 32
Name and number the substituents.
•Name the substituents as alkyl groups.
•Every carbon belongs to either the longest chain or a
substituent, not both.
•Each substituent needs its own number.
•If two or more identical substituents are bonded to the
longest chain, use prefixes to indicate how many: di- for
two groups, tri- for three groups, tetra- for four groups,
and so forth.

33. 33
 Combine substituent names and numbers + parent and suffix.
•Precede the name of the parent by the names of the substituents.
•Alphabetize the names of the substituents, ignoring all prefixes
except iso, as in isopropyl and isobutyl.
•Precede the name of each substituent by the number that indicates
its location.
•Separate numbers by commas and separate numbers from letters
by hyphens. The name of an alkane is a single word, with no
spaces after hyphens and commas.

34. Structural formula
2,2,4-trimethylpentane
Ball-and-Stick Model
Condensed structural formula is (2,2,4-trimethylpentane)

ةاجتا
دعلا

35. For example, all of the molecules shown below
share the same molecular formula, C6H14
(hexacarbon tetradecahydride?)
CC C C C H
H
H
H
C
H H H
HHHH
H
H
H
2-methyl-pentane2-methyl-pentane
CC C C C H
H
H
H
C
H H
HHHH
H
H
H
H
CC C C
H
H
H
C
H H
HH
C
H
H
H
H
H
H
H
CC C C
H
H
H
C
H
HH
C
H
H
H
H
H
H
H
H
3-methyl-pentane3-methyl-pentane
2,2-dimethylbutane2,2-dimethylbutane
2,3-dimethylbutane2,3-dimethylbutane

36. Isobutane can also be called
methylpropane-propane because it has
three carbon atoms in the main chain and
one methyl radical, CH3, replacing one of
the hydrogen atoms
Molecules with no branches in their chain are sometimes called
normal; thus butane is sometimes called normal butane or n-butane.
2-ethylpentane is a WRONG NAME.
It is actually 3-methylhexane.

37. Division of the Family
of Hydrocarbons (functional group)
Classification of Hydrocarbons

38. Olefins (sometimes called alkene)
Carbon-hydrogen combination of CnH2n, n being any number.
Olefine family consists of chain molecules that contain double carbon-
to-carbon bond, and are therefore UNSATURATED

39. Diolefins (sometimes called aldiene)
Carbon-hydrogen combination of CnH2n-2, n being any
number.
Diolefine family consists of chain molecules
that contain two double carbon-carbon bond,
and are therefore UNSATURATED

40. Acetylene
Carbon-hydrogen combination of CnH2n-2, n being any
number.
acetylene family consists of chain
molecules that contain triple double carbon- to-
carbon bond, and are therefore UNSATURATED

41. Cycloparaffins
Carbon-hydrogen combination of CnH2n, n being any
number.
Cycloparaffin family consists of chain
molecules that contain single ring structure with
one carbon-to-carbon bond, and are therefore
UNSATURATED

42. Aromatics
Carbon-hydrogen combination of CnH2n-6, n being any
number.
Aromatics
family consists of
chain molecules that
contain single ring
structure with double
carbon-to-carbon
bond, and are
therefore
UNSATURATED

43. Alcohol
Alcohols are similar to paraffins with one of hydrogen atoms
replaced with the hydroxyl radical OH.