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Interactions of Hazardous Materials
Intro to Organic Chemistry
Prepared by:
Dolores Gough, P.E.
George Gough, P.E., CSP
This presentation was prepared to provide some
background or refresher notes on selected and limited
topics in basic organic chemistry that may be of help
for the chemistry portion of the BOS 3640 course.
Your textbook is needed for some parts of this
presentation.
Basic Features of Atoms
Atom: smallest particle of an element; composed of smaller
particles known as electrons, protons, neutrons
Electrons: negative particles responsible for reactivity; charge of -1
Protons: positively charged particles; charge of +1
Neutrons: neutral particles; no charge
Electron
e --
P+
N
Nucleus
Protons and neutrons reside within the nucleus.
Electrons reside in designated regions surrounding the nucleus
called atomic orbitals.
Organic Chemistry – chemistry of compounds containing
one or more carbon atoms. However, the hydrogen atom is
almost always present in these compounds (shown in next slide).
Atomic Structure of Carbon
-
-
6P
6N
-
Carbon has four (4) electrons in the outer shell that need to bond for stability.
Carbon can also share electrons with other carbon atoms to form the following
types of carbon bonds:
C – C (single bond)
C = C (double bond)
C Ξ C (triple bond)
Hydrocarbons (HC) are compounds whose molecules consist of only
carbon and hydrogen atoms.
Atomic Structure of Hydrogen
-
1P
0N
Carbon electron sharing with Hydrogen: Hydrogen has one (1) electron in its outer shell that
can share with the C to form covalent bonds. However, C needs to share all 4 electrons in its
outer shell. Example: If all four electrons were shared with H, CH4 is formed.
H
H
C
H
H
or
CH4 (methane)
Carbon – Carbon Single Bond:
•
•
Alkanes: have general formula of CnH2n+2 where n = number of carbon atoms
Example: Butane has 4 carbons, all single bonds as shown:
H
I
H
I
H
I
H
I
H - C- C–C-C-H
I
I
I
I
H
H H H
•
C4H10 (see Table 12.1)
Cycloalkanes: same as alkane but the first and last C are linked (closed).
In naming them, just add “cyclo” to the alkane name. (Examples – see Sec. 12.2-B)
Cyclobutane
( http://commons.wikimedia.org)
Cyclohexane
http://commons.wikimedia.org
Organic Chemsitry Graphics retrieved from http://commons.wikimedia.org
Carbon = Carbon Double Bond:
•
•
Alkenes or Olefins: have general formula of CnH2n
Example: Butene has 4 carbons and at least 1 double bond
H
H
I
I
H - C- C=C-C–H
I
I I I
H H H H
or
C4H8
H H
I
I
H–C=C–C–C-H
I
I
I
H
H H
Carbon Ξ Carbon Triple Bond:
•
•
Alkynes: have general formula of CnH2n-2
Example: Butyne has 4 carbons and at least 1 triple bond
H
H
I
I
H - C- CΞC-C–H
I
I
H
H
or
H H
I
I
H – C ΞC – C – C - H
I
I
H H
C4H6
General Properties/Characteristics:
Alkanes (paraffins or saturated HC): relatively stable to chemical
reactions. Low molecular weight alkanes are gases or
liquids, high MW are solids.
Alkenes (olefins ): unsaturated HC because they don’t have the
maximum number of atoms each carbon is able to
accommodate; physical properties are closely
related to those of the corresponding alkanes
Alkynes (unsaturated HC): physical properties similar to those
of alkanes and alkenes
IUPAC System of Nomenclature
IUPAC (International Union of Pure and Applied Chemistry – used
for naming complex hydrocarbons)
When a hydrogen atom is removed from an alkane, the resulting
group is called alkyl group or alkyl substituent. See Table 12.2 (page
472) for common alkyl substituents.
Rules for naming an alkane (pages 472-473)
1
2
3
4
5
Example: CH3 - CH2 – CH - CH2- CH3
I
CH3
3-methyl pentane
Methyl (one carbon)
IUPAC SYSTEM (cont.)
Rules for naming alkenes (1 double bond), dienes (2 double bonds),
tienes (3 double bonds) & “cyclos”
1
Examples:
2
3
4
5
CH3CH = CHCH2CH3
1
2
3
2- pentene
4
CH2 = CH – CH = CH2
1, 3 - butadiene
Rules for naming alkynes (pages 479-480)
1
Examples:
2
3
4
5
6
CH3CH2C Ξ CCH2CH3
1
2
3- hexyne
3
CH Ξ CCH3
1- propyne
Aromatic Hydrocarbons
Regarded as compounds whose molecules are composed of
one or more special rings of carbon atoms
Benzene – simplest aromatic hydrocarbon
C 6H 6
http://commons.wikimedia.org
Other common aromatic compounds:
• Toluene (or methylbenzene)
• Xylene
1,4 dimethyl benzene
(para-xylene)
http://commons.wikimedia.org
http://commons.wikimedia.org
1,3 dimethylbenzene
(meta-xylene)
1, 2 dimethylbenzene
(ortho-xylene)
http://commons.wikimedia.org
http://commons.wikimedia.org
Organic Chemistry Graphics retrieved from http://commons.wikimedia.org
Polynuclear Aromatic Hydrocarbons (PAHs)
Two or more mutually-fused benzene rings per molecule (when a pair of
carbon atoms is shared and the bond between them)
Examples:
•Naphthalene (C10H8): colorless solid having odor of mothballs; poses
chronic respiratory hazard to humans; exposure is llinked with onset of
cancerous growths.
http://commons.wikimedia.org
• Anthracene (C14H10): component of coal-tar.
http://commons.wikimedia.org
Organic Chemistry Graphics retrieved from http://commons.wikimedia.org
Functional Groups
In a hydrocarbon, one or more hydrogen atoms may be substituted with
another atom or group of atoms. This atom or group of atoms is called the
functional group, and this group determines many of an organic compound’s
characteristic chemical properties. It identifies an organic compound as alcohol,
ether, aldehyde, etc.
There are over 100 functional groups; some of the important ones are covered
in the book and listed in Table 13.1.
Let us take some examples:
Functional group: hydroxyl (-OH)
Class of organic compound: alcohol
General formula: R-CH2-OH
Functional group: oxy (-O-)
Class of organic compound: ether
General formula: R-O-R’
where: R and R’ are arbitrary alkyl or aryl substituent
Alcohols
•Organic compounds derived by substituting one or more hydrogen
atoms in hydrocarbon molecule with hydroxy group (-OH)
•General chemical formula of simple alcohol is R-OH
Examples:
H
I
Methyl alcohol
(methanol)
H–C–O–H
or CH3OH
I
H
OH
1
3,5 dimethyl 3-hexanol
2
3I
CH3
4
5
/
6
CH3 CH2 C CH2 CH
I
CH3
methyl
\
CH3
methyl
Ethers
• Organic compounds that are highly volatile, flammable liquids
• Produce organic peroxides by reacting with atmospheric oxygen
catalyzed by light
• Highly reactive, potentially explosive
• General formula is R-O-R’
Example:
Diethyl ether
CH3CH2 - O - CH2CH3
(ethyl)
(ethyl)
Aldehydes and Ketones
\
C=O
/
•
Both contain the carbonyl group
•
Aldehydes - have carbonyl group located at end of chain of carbon
atoms
•
O
II
R–C–H
Ketone - has carbonyl group located at nonterminal position
within chain
O
II
R – C – R’
Examples of aldehyde: formaldehyde or methanal (CH2O);
acetaldehyde or ethanal (CH3CHO;
2-propenal or acrolein (CH2=CHCHO)
Examples of ketone: acetone or 2-propanone (CH3COCH3)
methyl ethyl ketone or 2-butanone
(CH3COCH2CH3)
Organic Acids
• Organic compounds containing the carboxyl group (-COOH), so
they are also called carboxylic acids. They are weak acids,
inherently corrosive, and water-soluble with characteristic odors.
• General formula is R – COOH
• In the IUPAC nomenclature, the suffix – oic acid is used to
designate carboxylic acids; but when the functional group (-COOH)
is connected to a cyclic structure, - carboxylic acid becomes the
appropriate suffix.
• Examples:
Methanoic acid (or formic acid): H COOH
Ethanoic acid (or acetic acid): CH3 COOH
Propanoic acid (or propionic acid): CH3CH2 COOH
connected to cyclic structure:
2- hydroxybenzene carboxylic acid (or salicylic):
o-HOC6H4 COOH
Peroxo-Organic Compounds
• Organic hydroperoxides, organic peroxides
• Many compounds unstable
• Used to induce polymerization, process
essential to production of plastics
Meyer (2014)
Meyer (2014) Chemistry of Hazardous Materials. (6th ed). NJ: Pearson
More details and other common
hazardous organic chemicals
are in the textbook.
Reference
Meyer, E. (2014). Chemistry of Hazardous Materials. (6th ed.). Upper Saddle River, NJ:
Pearson.
Organic chemistry graphics retrieved from http://commons.wikimedia.org