:
ORGANIC COMPOUNDS ALKANES
Urea was first discovered in human urine by H.M. Rouelle in 1773
It was synthesized in 1828 by Friedrich Wöhler and was
the first organic compound to be synthesized from inorganic starting materials
This discovery prompted Wöhler to write triumphantly to Berzelius:"I must tell you that I can make urea without the use of kidneys, either man or dog.
Ammonium cyanate is urea."
Friedrich Wöhler, who prepared it from
silver isocyanate through a reaction
with ammonium chloride
AgNCO + NH4Cl → (NH2)2CO + AgCl
NH4NCO → (NH2)2CO
Although Wöhler was attempting to prepare ammonium cyanate, by forming urea,
he inadvertently discredited VITALIZM, the theory that the chemicals
of living organisms are fundamentally different from inanimate matter,
thus starting the discipline of ORGANIC CHEMISTRY.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
An ORGANIC COMPOUND is any member of a large
class of chemical compounds whose molecules contain carbon.
The name "ORGANIC" is historical, dating back to the 19th century, when it was believed that
organic compounds could only be synthesized in living organisms through VIS VITALIS - the "life-force".
ORGANIC CHEMISTRY
the study of carbon containing compounds.
INORGANIC CHEMISTRY
the study of the elements and noncarbon compounds.
Inorganic exceptions:
CO, CO2, carbonates, bicarbonates, cyanides, cyanates, isocyanates
Na2CO3
Chemistry 21A
NaHCO3
NaCN
NaCNO
NaNCO
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Characteristics of organic substances
ORGANIC COMPOUNDS are generally covalently bonded.
This allows for unique structures such as long carbon chains and rings.
Carbon atoms form very stable covalent bonds with one another (catenation).
In contrast to inorganic materials, organic compounds typically
melt, boil, sublimate, or decompose below 300°C.
Neutral organic compounds tend to be less soluble in water compared to many
inorganic salts, with the
exception of certain compounds such as low molecular weight alcohols and
carboxylic acids where hydrogen bonding occurs.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Characteristics of organic substances
Organic compounds tend rather to dissolve in organic solvents which are
either pure substances like ether or ethyl alcohol,
or mixtures, such as the paraffinic solvents such as the various petroleum.
Like inorganic salts, organic compounds may also form crystals.
Unique property of carbon in organic compounds is that its valency does not
always have to be taken up by atoms of other elements, and when it is not, a
condition termed unstauration results. In such cases we talk about
carbon carbon DOUBLE BONDS or TRIPLE BONDS.
Double bonds alternating with single in a chain are called
CONJUGATED DOUBLE BONDS.
An aromatic structure is a special case in which the
conjugated chain is a closed ring.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Carbon compounds
Life as we know it is carbon based.
This means that most of the compounds you
are made of contain the element carbon.
You use carbon compounds every day.
Plastic, rubber, and gasoline, clothing, markers, tennis
rackets, are carbon compounds. Everything in house that is
not metal, ceramic or glass is organic/carbon material.
In fact, there are over 12 million known pure carbon
compounds (and imagine all possible mixtures)!
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
A carbon atom can form chemical bonds
with other carbon atoms in long chains
Carbon is unique among the elements.
or rings.
Some carbon compounds contain several
thousand carbon atoms.
glucose in cells
CARBOHYDRATES
The carbon compounds in living
things are classified into four
groups:
1. CARBOHYDRATES
2. LIPIDS
fat layer underneath skin - LIPIDS
hair - PROTEIN
cell membrane - LIPIDS
3. PROTEINS
4. NUCLEIC ACIDS
nucleus of cell – nucleic acids (DNA)
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
COMPOUNDS
Property
Organic
Inorganic
Bonding
covalent
ionic or covalent
Forces between
molecules
generally weak
quite strong
Number of
compounds
6 million+
around 250,000
Standard state
low melting solid,
liquid, or gas
solid
Water solubilty
mostly insoluble
mostly soluble
Organic solubilty
mostly soluble
mostly insoluble
Color
majority colorless
often colored
Conductibility
nonconductors
conductors in molten
or aqueous state
Combustibility
often flammable
very few burn
Rate of reactions
slow
fast
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
In the ground state of
the free carbon atom,
there are two unpaired
electrons in separate 2p
orbitals. In order to form
four bonds
(tetravalence), need four
unpaired electrons in
four separate but
equivalent orbitals.
Chemistry 21A
We assume that the
single 2s, and the three
2p orbitals of carbon mix
into four sp3 hybrid
orbitals which are
chemically and
geometrically identical;
the latter condition
implies that the four
hybrid orbitals extend
toward the corners of a
tetrahedron centered on
the carbon atom.
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Methane is the simplest
hydrocarbon; the molecule is
approximately spherical, as is
shown in the space-filling model:
In the ammonia molecule, for example, the nitrogen atom normally has three
unpaired p electrons, but by mixing the 2s and 3p orbitals, we can create
four sp3-hybrid orbitals just as in carbon. Three of these can form
shared-electron bonds with hydrogen, resulting in ammonia, NH3.
The fourth of the sp3 hybrid orbitals contains the two remaining
outer-shell electrons of nitrogen which form a non-bonding lone
pair. In acidic solutions these can coordinate with a hydrogen ion,
forming the ammonium ion NH4+.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
OXYGEN
Chemistry 21A
WATER
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
By replacing one or
more of the hydrogen
atoms in CH4 with
another sp3 hybridized
carbon fragments,
hydrocarbon chains of
any degree of
complexity can be built
up. The simplest of
these is ethane:
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
HYDROCARBONS
SATURATED
PARAFFINS
ALKANES
UNSATURATED
CYCLOALKANES
H H
ALKENES
H
C
H C C H
H
H H
RING WITH CONJUGATED
DOUBLE BONDS
ALKYNES
H C C H
H
C
H
AROMATICS
H
H
H
CONJUGATED
DOUBLE BONDS
Chemistry 21A
ISOLATED
DOUBLE BONDS
C
C
C
C
C
C
H
H
H
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
ISOMERS (Greek isos = "equal", méros = "part")
are compounds with
the same molecular formula but different structural formula
A simple example of isomerism is given by propane: it has the formula
C3H8O (or C3H7OH) and occurs as two isomers:
propan-1-ol (n-propyl alcohol; I) and propan-2-ol (isopropyl alcohol; II)
C3H8O
propan-1-ol (n-propyl alcohol) propan-2-ol (isopropyl alcohol) ethyl methyl ether
Structural isomerism, or constitutional isomerism,
is a form of isomerism in which molecules with the same
molecular formula have atoms bonded together in different orders
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
position isomerism
Example of skeletal isomerism
C5H12O
C5 H 1
pentan-2-ol
2
n-pentane
isopentane
(2-methylbutane)
functional group isomerism
C6H12
pentan-3-ol
This type of isomerism is due to the
unequal distribution of carbon atoms
on either side of functional group.
METAMERISM belongs to same
homologous series.
H3C
O
C
H2
H2
C
C4H10O H2
CH3 H C
3
methyl propyl ether
1-hexene
C
O
H2
C
CH3
diethyl ether
cyclohexane
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
FUNCTIONAL GROUPS
are specific groups of atoms within
molecules that are responsible for the
characteristic chemical reactions of
those molecules.
The same functional group will undergo
the same or similar chemical
reaction(s)regardless of the
size of the moleculeit is a part of.
However, its relative reactivity can be
modified by nearby functional groups.
methanol
(methyl alcohol)
Chemistry 21A
Ether
(ethyl ether)
(diethyl ether)
ethane
ethene (ethylene)
ethyne (acethylene)
Cumene
(isopropyl benzene)
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
FUNCTIONAL GROUPS
are specific groups of atoms within
molecules that are responsible for the
characteristic chemical reactions of
those molecules.
The same functional group will undergo
the same or similar chemical
reaction(s) regardless of the
size of the molecule it is a part of.
However, its relative reactivity can be
modified by nearby functional groups.
methylamine
Chemistry 21A
acetamide
acetaldehyde
(ethanal)
methyl ethyl ketone
(butanone)
.
C O
.
carbonyl
group
acetic acid
(ethanoic acid)
ethyl butyrate
(ethyl butanoate)
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
HYDROCARBONS
SATURATED
PARAFFINS
ALKANES
UNSATURATED
CYCLOALKANES
H H
ALKENES
H
C
H C C H
H
H H
RING WITH CONJUGATED
DOUBLE BONDS
ALKYNES
H C C H
H
C
H
AROMATICS
H
H
H
CONJUGATED
DOUBLE BONDS
Chemistry 21A
ISOLATED
DOUBLE BONDS
C
C
C
C
C
C
H
H
H
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Petroleum (L. petroleum, from Greek
πετρέλαιον, lit. "rock oil") or crude oil is a
naturally occurring, flammable liquid found
in rock formations in the Earth consisting of
a complex mixture of hydrocarbons of various
molecular weights, plus other organic compounds.
Four different types of hydrocarbon molecules
appear in crude oil.
The relative percentage of each varies from
oil to oil, determining the properties of each oil
Chemistry 21A
Composition by weight
Hydrocarbon
Average
Range
Alkanes
30%
15 to 60%
Cycloalkanes
49%
30 to 60%
Aromatics
15%
3 to 30%
Asphaltics
6%
remainder
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
ALKANES
≡
PARAFFINS
Latin parum (= barely) + affinis with the meaning here of "lacking affinity"
Name
Molecular
Formula
Structural
Formula
Isomers
Name
Molecular
Formula
Structural
Formula
Isomers
methane
CH4
CH4
1
hexane
C6H14
CH3(CH2)4CH3
5
ethane
C2 H6
CH3CH3
1
heptane
C7H16
CH3(CH2)5CH3
9
propane
C3 H8
CH3CH2CH3
1
octane
C8H18
CH3(CH2)6CH3
18
butane
C4H10
CH3CH2CH2CH3
2
nonane
C9H20
CH3(CH2)7CH3
35
pentane
C5H12
CH3(CH2)3CH3
3
decane
C10H22
CH3(CH2)8CH3
75
CH3–
C2H5–
CH3CH2CH2–
(CH3)2CH–
Ethyl
Propyl
Isopropyl
Alkyl
Group
Name
Methyl
Chemistry 21A
CH3CH2CH2CH2–
Butyl
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
THE ALPHABET
OF ORGANIC CHEMISTRY
methane
CH4
CH4
1
hexane
C6H14
CH3(CH2)4CH3
5
ethane
C2 H6
CH3CH3
1
heptane
C7H16
CH3(CH2)5CH3
9
propane
C3 H8
CH3CH2CH3
1
octane
C8H18
CH3(CH2)6CH3
18
butane
C4H10
CH3CH2CH2CH3
2
nonane
C9H20
CH3(CH2)7CH3
35
pentane
C5H12
CH3(CH2)3CH3
3
decane
C10H22
CH3(CH2)8CH3
75
Alkyl
Group
Name
CH3–
Methyl
C2H5–
CH3CH2CH2–
(CH3)2CH–
Ethyl
Propyl
Isopropyl
Chemistry 21A
CH3CH2CH2CH2–
Butyl
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
General formula
for alkanes:
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Nowadays, the main source of methane is
"Natural Gas", which originates in the same way
as crude oil, by the anaerobic decomposition of
microscopic sea animals under the pressure of
layers of silt and mud over a period of millions of
years. This can also occur in swamps and marshes,
when plant matter decays ("marsh gas"), and in
landfill sites; in digesters breaking down sewage
sludge; and by enteric fermentation in livestock
(e.g. ruminants such as cattle and sheep), as well
as being formed when termites digest the cellulose
in the wood they have eaten.
anaerobic
in absence of air (oxygen)
Cows and other ruminants have methanogenic
bacteria in their rumen which can turn digested
carbon compounds into methane, emitted as
flatus, some 200-300 litres of gas a day.
Most of the flatus is nitrogen, but cases have
been reported of cows' flatus being ignited,
though not explosively.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
The alkanes from pentane (C5H12) to octane (C8H18)
are refined from petroleum into gasoline,
the ones from nonane (C9H20) to hexadecane (C16H34)
into diesel fuel and kerosene (primary
component of many types of jet fuel), and the ones
from hexadecane upwards into fuel oil and
lubricating oil. At the heavier end of the range,
paraffin wax is an alkane with approximately 25
carbon atoms, while asphalt has 35 and up.
pentane (C5H12)
to octane (C8H18)
paraffin wax
C9H20 to C16H34
approximately 25 carbon atoms
Chemistry 21A
asphalt has 35 C and up
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
H3C
C
H2
H2
C
CH3
CH3
C
H3C H CH3
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
NORMAL ALKANE =
STRAIGHT CHAIN ISOMER
BRANCHED ALKANES
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
CONFORMATIONS
CONFORMATIONAL ISOMERISM
is a form of stereoisomerism in which molecules with the same structural
formula (same connectivity) exist as different conformational isomers or
conformers in 3-D due to rotations about one or more σ (single) bonds.
The most stable conformer
staggered ethane
eclipsed ethane
The most unstable conformer
Natta projection method: Solid or dashed wedged bonds represent bonds
pointing above-the-plane or below-the-plane of the paper, respectively.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
CONFORMATIONS
Newman projection formulas
H
H3C
H2
C
butane
C
H2
CH3
H3C
H
CH3
staggered butane
H
H
The most stable conformer
H3C
C C
H2 H2
CH3
The most unstable conformer eclipsed butane
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
IUPAC Rules for Alkane Nomenclature
1. Find and name the longest continuous carbon chain.
2. Identify and name groups attached to this chain.
3. Number the chain consecutively, starting at the end nearest a substituent group.
4. Designate the location of each substituent group by an appropriate
number and name.
5. Assemble the name, listing groups in alphabetical order.
The prefixes di, tri, tetra etc., used to designate several groups of
the same kind, are not considered when alphabetizing.
ALKYL GROUP is a group differing by one hydrogen from alkane
Group
Name
CH3–
Methyl
C2H5–
CH3CH2CH2–
(CH3)2CH–
Ethyl
Propyl
Isopropyl
Chemistry 21A
CH3CH2CH2CH2–
Butyl
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
non-alkyl groups:
Group
F
Cl
Br
I
NO2
NH2
Name
fluoro
chloro
bromo
iodo
nitro
amino
Systematic name
Common/Trivial
name(s)
Chem.
formula
Chloromethane
Methyl chloride
CH3Cl
Dichloromethane
Methylene
chloride
CH2Cl2
Trichloromethane
Chloroform
CHCl3
Tetrachloromethane
Carbon
tetrachloride,
Freon 10
CCl4
polytetrafluoroethene
PTFE, Teflon
-[CF2-CF2]x
it is the only known surface
to which a gecko cannot stick
H3C
NO2
nitromethane
methylamine
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
General (IUPAC) nomenclature principle
CH3CH2CH2CH(CH3)2
CH3CH2C(CH3)2CH2CH2CH3
PREFIX
ROOT
ENDING
number
and
identity of
attached
groups
longest
carbon
chain
functional
class
(CH3CH2)2CHCH2CH(CH3)2
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
CH3CH2CH2CH(CH3)2
Functional group is an alkane, therefore suffix = -ane
The longest continuous chain is C5 therefore root = pent
The branch is a C1 alkyl group i.e. a methyl group
The first point of difference rule requires numbering from
the right as drawn, the substituent locant is 2-
2-methylpentane
CH3CH2C(CH3)2CH2CH2CH3
(CH3CH2)2CHCH2CH(CH3)2
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
CH3CH2CH2CH(CH3)2
CH3CH2C(CH3)2CH2CH2CH3
3,3-dimethylhexane
Functional group is an alkane, therefore suffix = -ane
The longest continuous chain is C5 therefore root = pent
The branch is a C1 alkyl group i.e. a methyl group
The first point of difference rule requires numbering from
the right as drawn, the substituent locant is 2-
2-methylpentane
Functional group is an alkane, therefore suffix = -ane
The longest continuous chain is C6 therefore root = hex
There are two substitutents, both C1 alkyl group i.e. methyl groups
The first point of difference rule requires numbering from the left as
drawn, the substituent locants are 3- and 3-
(CH3CH2)2CHCH2CH(CH3)2
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
CH3CH2CH2CH(CH3)2
CH3CH2C(CH3)2CH2CH2CH3
3,3-dimethylhexane
(CH3CH2)2CHCH2CH(CH3)2
4-ethyl-2-methylhexane
Chemistry 21A
Functional group is an alkane, therefore suffix = -ane
The longest continuous chain is C5 therefore root = pent
The branch is a C1 alkyl group i.e. a methyl group
The first point of difference rule requires numbering from
the right as drawn, the substituent locant is 2-
2-methylpentane
Functional group is an alkane, therefore suffix = -ane
The longest continuous chain is C6 therefore root = hex
There are two substitutents, both C1 alkyl group i.e. methyl groups
The first point of difference rule requires numbering from the left as
drawn, the substituent locants are 3- and 3-
Functional group is an alkane, therefore suffix = -ane
The longest continuous chain is C6 therefore root = hex
One C1 alkyl group substituent i.e. a methyl group
One C2 alkyl group substituent i.e. an ethyl group
The first point of difference rule requires numbering from the
right as drawn, the substituent locants are 2- and 4-
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
The longest chain: PENTANE
Substrituents: three methyl groups
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
The longest chain: PENTANE
Substrituents: three methyl groups
Name: 2,2,4-trimethylpentane
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Examples of Simple Cycloalkanes
Name
Molecular
Formula
Cyclopropane
C3H6
Cyclobutane
Cyclopentane
C4H8
C5H10
Structural
Formula
Cyclohexane
C6H12
Cycloheptane
C7H14
Cycloalkane
CnH2n
(CH2)n
Line
Formula
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
CYCLOHEXANE
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Alicyclic compounds can display cis-trans isomerism
(geometric isomerism or configuration isomerism)
When the substituent
groups are oriented
in the same direction,
the diastereomer is
When the substituents
are oriented in
opposing directions,
the diastereomer is
referred to as cis
referred to as trans.
cis-1,2-dichlorocyclohexane
Chemistry 21A
trans-1,2-dichlorocyclohexane
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
1,1-dimethylcyclohexane
1-t-butyl-1-methylcyclohexane
cis-1,2-dimethylcyclohexane
trans-1,2-dimethylcyclohexane
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
cis-1,2-dimethylcyclopentane
trans-1,2-dimethylcyclopentane
cis-1,2-dibromocyclopentane
trans-1,2-dibromocyclopentane
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Melting (blue) and boiling (pink)
points of the first 14 n-alkanes in °C.
CH4 to C4H10 alkanes are
gaseous;
from C5H12 to C17H36 they
are liquids;
and after C18H38 they are
solids
R.T.
As a rule of thumb, the boiling
point rises 20 - 30 °C for each
carbon added to the chain
A straight-chain alkane will have a boiling point higher than
a branched-chain alkane due to the greater surface area in
contact, thus the greater van der Waals (dispersion) forces,
between adjacent molecules.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
a HOMOLOGOUS SERIES
is a series of organic compounds with a similar general formula,
possessing similar chemical properties due to the presence of
the same functional group, and shows a gradation in physical
properties as a result of increase in molecular size and mass
HYDROPHOBIC (water in Greek hydro- and fear phobos)
refers to the physical property of a molecule (known as a hydrophobe)
that is repelled (insoluble in) from a mass of water.
HYDROPHILIC, from the Greek (hydros) "water" and φιλια
(philia) "friendship," refers to a physical property of a molecule
that can transiently bond with water (H2O) through hydrogen bonding
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
CH4 + 2O2 →
CO2 + 2H2O + 213 kcal/mol
Provided the combustion is complete, all the hydrocarbons will burn with a
blue flame. However, combustion tends to be less complete as the number of
carbon atoms in the molecules rises. That means that the bigger the
hydrocarbon, the more likely you are to get a yellow, smoky flame.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Incomplete combustion (where there isn't enough oxygen present) can lead to
the formation of carbon or carbon monoxide.
As a simple way of thinking about it, the hydrogen in the hydrocarbon gets the
first chance at the oxygen, and the carbon gets whatever is left over!
2CH4 + 3O2 → 2CO + 4H2O
CH4 + O2 → C + 2H2O
The presence of glowing carbon particles in a flame turns it
yellow, and black carbon is often visible in the smoke.
Carbon monoxide is produced as a colourless poisonous gas.
Oxygen is carried around the blood by haemoglobin (US: hemoglobin).
Unfortunately carbon monoxide binds to exactly the same site on the
haemoglobin that oxygen does.
The difference is that carbon monoxide binds irreversibly - making that particular
molecule of haemoglobin useless for carrying oxygen. If you breath in enough
carbon monoxide you will die from a sort of internal suffocation.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
CRACKING is the process whereby complex organic molecules
such as kerogens or heavy hydrocarbons are broken down into simpler
molecules (e.g. light hydrocarbons) by the breaking of carbon-carbon
bonds in the precursors.
CRACKING, also referred to
as PYROLYSIS, is the
breakdown of a large alkane into
smaller, more useful alkanes and
an alkene.
Simply put,
hydrocarbons
cracking is the
process of
breaking long chain
hydrocarbons into
short ones.
Factory of Shukhov
cracking process,
Baku, USSR, 1934.
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
CH4 + Cl2 + energy
CH4 + Cl2 + energy
——>
——>
CH3Cl + HCl
CH3Cl + CH2Cl2 + CHCl3 + CCl4 + HCl
The relative amounts of the various products depend on
the proportion of the two reactants used.
In the case of methane, a large excess of the hydrocarbon
favors formation of methyl chloride as the chief product;
whereas, an excess of chlorine favors formation of
chloroform and carbon tetrachloride.
Alkanes react easily
with halogens
forming haloalkanes.
Chemistry 21A
Systematic name
Common/Trivial
name(s)
Chem.
formula
Chloromethane
Methyl chloride
CH3Cl
Dichloromethane
Methylene
chloride
CH2Cl2
Trichloromethane
Chloroform
CHCl3
Tetrachloromethane
Carbon
tetrachloride,
Freon 10
CCl4
polytetrafluoroethene
PTFE, Teflon
-[CF2-CF2]x
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Chemistry 21A
Dr. Dragan Marinkovic
:
ORGANIC COMPOUNDS ALKANES
Chemistry 21A
Dr. Dragan Marinkovic