Lecture 3Lecture 3
Hazardous Waste – Chapter 2
Common Hazardous WastesCommon Hazardous Wastes
Most common classes of hazardous compounds:
Petroleum products Solvents Pesticides Polychlorinated biphenyls Dioxins Metals
Common Hazardous WastesCommon Hazardous Wastes
Need to learn the language of Haz WasteNomenclature and Structure required to
Determine rates of transport & transformation Evaluate toxicity and risk Design remediation
Organic Carbon – – molecules containing carbon and hydrogen and
possibly oxygen, nitrogen, phosphorus, sulfur, and halogens, derived from a biological source
Common Hazardous WastesCommon Hazardous Wastes
Inorganic – mineralsCarbon bonding
– Two types of bonding Ionic – donation of valence electron, NaCl Covalent
– shared valence electrons, following the octet rule
– Atoms want to fill their outmost shell, H2
– Overlap of orbitals
Common Hazardous WastesCommon Hazardous Wastes
Electrostatic forces hold both ionic and covalent bonds together– Organic compounds have covalent bonds,
carbon can not release a donated electron completely
– Many chemical bonds exhibit characteristics that are covalent and ionic (dipole)
Common Hazardous WastesCommon Hazardous Wastes
Dipole– Charge separation resulting from the covalent bond
between two different atoms– The electron cloud is pulled towards the larger electron
density Negative dipole – atom with higher e- density Positive dipole – atom with fewer e-
– Bond polarity (electron density) can affect treatment of hazardous waste, determining treatment technologies
Common Hazardous WastesCommon Hazardous Wastes
Nomenclature– Two major divisions of organic compounds
Aliphatic compounds – straight and branched chains of carbon atoms, classified as alkanes, alkenes, alkynes, etc.
Aromatic comopounds – carbon-based rings with resonating conjugated double bonds (benzene)
Common Hazardous WastesCommon Hazardous Wastes
Isomerism– The different ways to write chemicals:
Empirical formula – glucose, CH2O, ratio of the elements in the molecule
Chemical formula – C6H12O6, number of each atom in the molecule
Structural formula – drawing of the compound with straight lines representing the bond
Common Hazardous WastesCommon Hazardous Wastes
Isomers– the different arrangements that organic
compounds can take while having the same chemical formula
– Three dimensional movement of the atoms– The more carbon atoms, the more isomers– Widely different characteristics
Common Hazardous WastesCommon Hazardous Wastes
Organic Nomenclature Systems 1. International Union of Pure and Applied Chemists
(IUPAC)
2. Common and Trivial Names
3. Trade Names
Need to have a basic understanding of all three in dealing with hazardous waste
Common Hazardous WastesCommon Hazardous Wastes
Alkanes– Straight or branced chains of carbon and
hydrogen– Bonds are not fixed, but are constantly rotating bonds – 3D– Table 2.2 Names of straight-chain alkanes up to
20 carbons– Isomers of alkanes with more than 4 carbons
can cause a nomenclature nightmare
Common Hazardous WastesCommon Hazardous WastesNumber Name
1 Methane
2 Ethane
3 Propane
4 Butane
5 Pentane
6 Hexane
7 Heptane
8 Octane
9 Nonane
10 Decane
11 Undecane
12 Dodecane
13 Tridecane
14 Tetradecane
15 Pentadecane
16 Hexadecane
17 Heptadecane
18 Octadecane
19 Nonadecane
20 Eicosane
Common Hazardous WastesCommon Hazardous Wastes
– The nomenclature problem with alkanes is solved through the use of substituent groupes or radicals
– For alkanes the radicals are called alkyl groups and lack on H from the parent group
-CH3 Methyl
-CH2-CH3 Ethyl
– Table 2.3 Common Alkyl Groups
Common Hazardous WastesCommon Hazardous Wastes
IUPAC Nomenclature for Alkanes1. Select the carbon skeleton with the longest chain as the
parent compound2. Assign numbers to the carbons where the alkyl group is
attached3. If more than one of a given substituent group is attached to
the skeleton, use a prefix to show how many of these groups are on the molecule
4. Commas always separate numbers and hyphens always separate words
5. The order of the substituent groups in the name should be alphabetical
Common Hazardous WastesCommon Hazardous Wastes
Common Names of Alkanes / Alkyl Derivatives– Perfix iso-, used in the petroleum industry for naming
alkanes branced at one end, primarily for smaller alkanes
– In industry the prefixes in Table 2.5 are often used
Common Hazardous WastesCommon Hazardous Wastes
Alkenes– Characterized by a double bond somewhere in
the molecule ylene is the older IUPAC ene is the new, but everyone uses ylene suffix No rotation occurs around the double bond, the
carbons are fixed Table 2.6 gives the rules for naming Alkenes
Common Hazardous WastesCommon Hazardous Wastes
Rules for naming Alkenes1. The longest carbon skeleton containing the double
bond serves as the basis for naming the compound, -ene suffix instead of –ane
2. Number the first double-bonded carbon on the longest chain so that it has the lowest possible #
3. Name alkyl substituents in the same manner as alkanes
4. Give a special prefix to an alkene across the plane of the double bond cis – same side, trans – continues on the opposite side of the double bond
Common Hazardous WastesCommon Hazardous Wastes
Alkynes and Organic Acids– Alkynes
Triple carbon-carbon bond named the same as alkanes, except with a –yne suffix
– Organic Acids Contain a carboxylic group –COOH, in place of one terminal
methyl group, -anoic acid suffix
– Aldehyde COH, -al suffix
– Cyclohexane
Common Hazardous WastesCommon Hazardous Wastes
Aromatic Compounds– Alternating single and double bonds between carbon
atoms joined in a ring– Resonating double bond, provides stability, has an
aromatic (sweet) odor– Naming, substituent first followed by benzene or Ph,
for phenyl– When more than one group is added to a ring, the name
of the position on the ring is stated as Ortho (-o), Meta (-m), or Para (-p)
Common Hazardous WastesCommon Hazardous Wastes
Polycyclic Aromatic Hydrocarbons (PAH)– Two or more benzene rings bound together– Also known as polynuclear aromatic compounds (PNA)
PNA is a more general term, the molecule can contain O, N, or S
– PAH’s contain only C in the ring petroleum products, cigarette smoke, automobile exhaust
– Smallest PAH’s are naphthalene and anthracene– There are 35 prescribed IUPAC compounds– Table 2.8 gives the Nomenclature rules
Common Hazardous WastesCommon Hazardous Wastes
PAH Nomenclature Rules1. Draw the PAH rings so that two of the sides are
vertical
2. Draw as many rings as possible in a horizontal line
3. Number the periphery of the ring clockwise, starting at the first carbon atom not a part of ring fusion, of the right hand ring of the top row
Common Hazardous WastesCommon Hazardous Wastes
Petroleum– Naturally occurring complex mixture of
hydrocarbons– Big problem!– UST’s – put underground to prevent fires, now
leaking into groundwater– Used by everyone, 2.43 x 109 barrels/year– Used in auto’s, heating, power generation, etc.
Common Hazardous WastesCommon Hazardous Wastes
Petroleum– Contamination not due to consumption but how
much UST’s leak and how many spills there are– Crude oil and petroleum products are highly
variable– Consist primarily of aliphatic and aromatic
hydrocarbons
Common Hazardous WastesCommon Hazardous Wastes
Four classes of PAH’s in Crude oil:– Parafins – alkanes– Olefins – alkenes– Napthenes – cycloalkanes– Aromatics – monocyclic aromatic
hydrocarbons and PAH’s
Common Hazardous WastesCommon Hazardous Wastes
Petroleum– Crude oil
Refined, Reformed, and Distilled before use– Refining involves: separtation (distillation), conversion
(cracking), and upgrading (hydrocracking)
– Distillation ranges shown in Table 2.11
BTX– Benzene, Toluene, Xylene, an important group found in
gasoline, 6-36% of gasoline
Common Hazardous WastesCommon Hazardous Wastes
Non-Halogenated Solvents– Most common are petroleum distillates,
aliphatic and aromatic hydrocarbons, alcohols, ketones, esters, and ethers
– Used for cold cleaning, metals degreasing, paint stripping, carriers in paint, varnishes and ink
Common Hazardous WastesCommon Hazardous Wastes
Hydrocarbons– Mineral spirits – paint thinner, dry cleaning– BTX also used for cleaning
Ketone– Table 2.14 for nomenclature rules– C=O in the middle of a carbon chain– Common names are used most often, Acetone,
etc.
Common Hazardous WastesCommon Hazardous Wastes
Alcohols and Esters– Alcohol has the (-OH) group, -ane is replaced
by (-anol)– Esters are derivatives of alcohol, -ane is
replaced by -anate
Common Hazardous WastesCommon Hazardous Wastes
Halogenated Solvents– Halogenated hydrocarbons produce better
solvents than non-halogenated Chlorination is the most wide spread industrial
practice for metals cleaning They contaminate GW in Metro areas due to
dumping High density, relative high water solubility, low
degradability
Common Hazardous WastesCommon Hazardous Wastes
Common halogenated hydrocarbons– Methylene chloride, Chloroform, Carbon
Tetrachloride– Dip cleaning is primarily responsible for
environmental releases– Other major category of chlorinated derivatives
Chlorinated derivatives of ethane and ethylene– TCA, TCE and PCE
HomeworkHomework
Chapter 2: 1, 3, 4, 5, 8