1. DR. R.K. KHANDAL
DIRECTOR
WORKSHOP ON HYDROCARBONS
SHRIRAM INSTITUTE FOR INDUSTRIAL RESEARCH
19, UNIVERSITY ROAD, DELHI - 110007
Email : sridlhi@vsnl.com Website : www.shriraminstitute.org

2. OUTLINE
 What are they ?
 How are they formed ?
 Types of Hydrocarbons ?
 Characterization of Hydrocarbons ?
 Environmental issues
 Degradation and Biodegradation ?
 Bioremediation ?
Everything about Hydrocarbons

3. Hydrocarbons: What are they ?
 Compounds consisting of Carbon & Hydrogen
 Covalent bonding
 Varying Molecular Weights
 Exist in all three states: Gas; Liquid; Solid
 Used as fuel, solvent, coating, base material
Non-Renewable
Non-Polar
Petroleum as the source
Non-degradable

4. Hydrocarbons: What are they
Li
Na
K
Rb
 H is first element
 C is first of IV group; middle of first row of Periodic table
A Range of Chemicals based on C & H
Cs
Be
Mg
Ca
Sr
Ba
B
Al
Ga
In
Tl
C
Si
Ge
Sn
Pb
N
P
As
Sb
Bi
O
S
Se
Te
Po
F
Cl
Br
I
At
He
Ne
Ar
Kr
Xe
Fr Ra
H
Rn

5. Hydrocarbons: What are they ?
 Nonionic in nature
 Carbon as a base
 Hydrogen as an acid
 A big chain length - - - - C- C - C- C - - - -
 Completely non-polar; Insoluble in water
Hydrocarbons are naturally occurring
substances; but not renewable !

6. Hydrocarbons:How are they formed ?
 2 Electrons in p orbital
 Should loose 2 electrons
like other elements in its
group
 Instead bonds covalently
 sp3
hybridized
C H
1s2
2s2
2p2 1s1
 I group I element; 1 e-
 Can exist as Hydride or
Hydrogen derivative
 Only one electron to take
part in bonding
 Shares to form covalent
bond

7. Hydrocarbons : How are they formed?
C
1s2 2s2
2p2
H
1s1
Hybridization
p3
s
sp3
orbitals s orbital

8.  One carbon has 4 sp3
hybridized orbitals
 All four can share one electron each
 4 H 1s orbitals combine to form CH4
Hydrocarbons : How are they formed?
No polarization ; no polarity
C
H
1s
H
1s
H
1s
H
1s
C C
H
H H HCH4 CH4

9.  Carbon can bond with carbon besides bonding with hydrogen
Since all bonds are formed by sharing of an electron
each from two different orbitals; σ bond is formed
Saturated alkane molecule CnH2n+2
C C C C
Hydrocarbons : How are they formed?
H H H H
HHHH

10.  Carbon can combine with carbon with more than one bond,
when hydrogen atoms are less than those present in alkanes
Unsaturated alkenes (2 bonds) and alkynes ( 3 bonds)
C
C H- C≡C-H
C C C=C
H
H
H
H
Hydrocarbons : How are they formed?
CnH2n
CnH2n-2

11. In the nature, compounds of carbon and hydrogen
exist in hydrated form; carbohydrates
All hydrocarbons are formed in the nature through
evolutionary process, but they are non- renewable !
Carbohydrates form by photosynthesis process in plants
In addition to C & H, they also contain O
Carbohydrates are sources of energy for all living systems
Hydrocarbons : How are they formed ?

12. Carbohydrates
Hydrocarbons : How are they formed ?
Biomass of plants & living species
• Pressure
• Temperature
• Microbes
• Enzymes
Dehydroxylation
Hydrocarbons
Burried under the earth
Lignite Coal Crude oil Natural gas
< 500 m < 1000 m > 600 m > 600 m
• pH
• Catalysts

13. Petroleum
 Micro-organisms or sea animals origin
 Occur under earth’s crust 600-6000 m depth
Crude oil/ Petroleum Useful fractions
Remains of
dead Micro-
organisms
Covered
by sand/
clay
Sank at
bottom of
sea
Petroleum
High temperature,
Pressure, Absence
of air, Bacterial
action
Also called crude oil
Mixture of 150 different organic compounds
Refining

14. Petroleum : Occurrence
To oil
refinery To supply
line
Rocks
Natural gas
Petroleum
Sea water
Soil
Crude
oil well

15. 101 Production of Petrochemicals
GasolinePetroleum
Refinery
Petroleum gas (Ethane,
propane, butane)
Naphtha
Reforming
Methane Ethane Ethene Propane Butane
Hydrogen
Benzene
Toluene
Xylene
Hydrogen
Cyclohexane

16. Cracking
Thermal
Liquid phase
High boiling
lubricating oil
Vapor phase
Low boiling
fraction
Low boiling
fraction
SteamCatalytic
High
hydrocarbons
(Catalyst SiO2 : Al2O3: MnO2)
4 : 1 : 1
Low hydrocarbons
eg. Gasoline
production
477 o
C
327-377 o
C
2 atm , catalyst
High hydrocarbons
in vapor phase
Heat, 900o
C
Low unsaturated
hydrocarbons
Cooled rapidly

17. 17
Cracking/
breaking down/
pyrolysis
C10H22 C8H18 + C2H4
∆
497 o
C
 C-C bonds are broken in random manner
 Yield of low boiling fractions (low molecular mass) eg. Gasoline
is increased by the cracking of less useful high boiling fraction
Higher hydrocarbons Lower hydrocarbons
Cracking of Hydrocarbons
Cracking
Cracking always leads to low boiling alkenes as by-products
Products obtained from cracking depends on:
 Structure of alkane
 Pressure
 Catalysts
C16H34 C8H18 + C8H16
Low boiling volatile
High boiling

18. 18
n- Hexane
- H2
397 o
C, Pt
Production of aromatic hydrocarbons like
benzene & Toluene
Increase aromaticity hydrocarbons
Increase octane number of gasoline
Reforming/ Aromatization
- 3H2
cyclohexane benzene
CH3
H2C
CH2
CH2
CH2
CH3

19. 19
Liquified Petroleum Gas (LPG) : Low boiling fractions of
petroleum
LPG & CNG
 Used as domestic & industrial fuel
 As a source of low molecular mass petrochemicals
Liquified under
pressure
Compressed Natural gas (CNG) - Mixture of
Methane 60-90%(main constituent)
Ethane 5-9%
Propane 3-18%
Butane 2-14%
CO2, N2, H2S <1% each
Ethane, Propane , Butane Liquified petroleum gas
(main constituents)

20. Coal : Classification
Element
Carbon
Peat
54
Lignite
84
Bituminous Anthracite
Hydrogen
Oxygen
Nitrogen
Sulphur
5.5
35
2
3.5
64
5
26
1.3
3.3
8
4.5
1.3
1.5
93
3.3
2.0
1.3
0.5
Anthracite is the richest in carbon content

21. 21
Fischer Tropsch process Bergius process
Synthetic Petrol
n C + (n+1)H2(g) CnH2n+2
(coal) (mixture of hydrocarbons)
Iron oxide
200-250 atm
475 o
C
Bergius process
C (red hot) + H2O(g) CO + H2
(coke)
n CO + (2n+1) H2 CnH2n+2 + nH2O
5-10 atm,
177-202 o
C
Co catalyst
Fractional
distillation
Fischer Tropsch process
Coal
Petrol
Water gas

22. 101 Destructive Distillation of Coal
Volatile
Coal
Solid
residue
Undissolved
gases
Soluble
gases
Upper
aqueous
layer
Lower
layer
Coke ~ 70%
by mass
Passed through water
Allowed to standCoal gas ~ 17%;
mainly alkanes &
alkenes
Ammonical liquor ~ 8-10 %
Coal Tar ~ 4-5 %

23. 101 Fractional Distillation of Coal Tar
Light Oil ~ 2.25 %
Coal Tar
Upto 170 °C
Benzene, Toluene, Xylene
170 - 230 °C
Middle Oil ~ 7.5 %
Phenol, Cresol, Naphthalene
Heavy Oil ~ 16.5 %
230 - 270 °C
Anthracene
Oil ~ 12 %
270 - 360 °C
Cresol, Naphthalene, Naphthol
Carbon still remains as a residue with ~ 56 % content
Anthracene

24. Hydrocarbons : Types
CharacteristicsParameter Type
C-C Bond
Single C-C bond
Double C=C bonds
Triple C≡C bonds
Alkanes
Alkenes
Alkynes
Shape
Straight chain
Ring structure
Ring structure with
delocalized e-
Chain length
No. of C-atoms involved
 <C5
C6-C17
 >C18
All of them are non-polar
Acyclic
Cyclic
Aromatics
 Gas
Liquid
Solid

25. Behaviour
Increases with unsaturation
Decreases with increase in chain length
Increases with increase in chain length
Decreases with branching
Decreases with unsaturation
Parameter
Boiling Point
Reactivity
Hydrocarbons : Behaviour & Properties

26. 26
Why Cyclopropane is very reactive when
compared to Cyclohexane ?
C - C - C bond angle = 60o
in cyclopropane
C - C - C bond angle = 90o
in cyclobutane
C - C - C bond angle = 120o
in cyclohexane
Angle strain in cyclopropane = 1/2(109.3 - x) = 1/2(109.3 - 60o
) = 24o
40’
Angle strain in cyclobutane = 1/2(109.3 - x) = 1/2(109.3 - 90o
) = 9o
6’
Angle strain in cyclohexane = 1/2(109.3 - x) = 1/2(109.3 - 120o
) = - 5o
16’
 Deviation is more in case of cyclopropane making it highly
strained and hence, more reactive than cyclohexane

27. Hydrocarbons: Characterization
Characterize as per chemistry and with reference to
the requirements of the application
Characterization
Compositional Physical properties Chemical properties
IR/UV
GC
GC/MS
LC
LC/MS/MS
Melting point
Boiling point
Vapour pressure
Calorific value
Solubility
Viscosity
Unsaturation
Reactivity
Chain length
Structure
Conformation

28. Hydrocarbons: Environmental Issues
Certain hydrocarbons are carcinogenic in nature
Aromatics  Poly-aromatics
Water should be treated well before being put into
river or water bodies
Degradation & remediation are the key tasks
Carcinogenic hydrocarbons getting into food
chain is a major cause of concern
Water  Food  Feed

29. 101Hydrocarbons : Environment Issues
Crude oil Spillage getting into
water bodies
Process step Pollution
Water Oil
Desalting
Water with salts Oil
Petrochemicals
Water must be treated well before reuse etc.
Contamination of
HCs in water
Water contaminated
with HCs
Demulsification
Various
processes
Effluent Water

30. 101Hydrocarbons: Treatment of Water
Contaminated water
Step
Various types of surfactants play a key role
Check
Deoiling
Reuse
Oil Water
Level of
contamination
Right type of
surfactants
Compliance as per
guidelines

31. 101Hydrocarbons: Water Oil Systems
Selection of suitable surfactant is the key
Oil Water
Oil Hydrophobe
Water Hydrophile
Separation is spontaneous unless solubilized / emulsified
Water in oil Oil in water
Oil Water
Surfactant Surfactant

32. Hydrocarbons: Degradation
Degradation of hydrocarbons is not easy because of
strong bonding of C-C and C-H bonds; no polarization
Hydrocarbons
Degradation
∆ E
Breaking of bonds
Formation of short chain molecules
from long chain ones
Ultimately to elements C as CO2 and H as H2O
∆ E Bio or chemical process

33. Hydrocarbons: Degradation & Biodegradation
Hydrocarbons
Chemical Process
pH Solar Radiations
Biological Process
Adsorption on soils
Solubility in water
Creation of activity
Smaller molecules
Adsorption on soils
Solubility in water
Taken up by microbes
Enzymatic reactions
Smaller molecules
Emulsion
Solubilisation

34. Hydrocarbons: Bioremediation
Hydrocarbons
Bio-remediation Phyto-remediation
Isolation of microbes
Picked up by plants
Culturing microbes
eating hydrocarbons
Biodegradation
Emulsion Solution
Plant metabolism
Phyto-remediation

35. Hydrocarbons: Degradation
The factors can be maneuvered to facilitate
degradation of hydrocarbons
Degradation Factors
Solubility
in water
Emulsion in
water
O/W
W/O
Energy
absorption
from solar
radiations
Chemicals
Environment
pH
Catalysts

36. THANK YOU