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Lecture 3 Hazardous Waste – Chapter 2. Common Hazardous Wastes Most common classes of hazardous compounds: Petroleum products Solvents Pesticides Polychlorinated.

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Presentation on theme: "Lecture 3 Hazardous Waste – Chapter 2. Common Hazardous Wastes Most common classes of hazardous compounds: Petroleum products Solvents Pesticides Polychlorinated."— Presentation transcript:

1 Lecture 3 Hazardous Waste – Chapter 2

2 Common Hazardous Wastes Most common classes of hazardous compounds: Petroleum products Solvents Pesticides Polychlorinated biphenyls Dioxins Metals

3 Common Hazardous Wastes Need to learn the language of Haz Waste Nomenclature 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

4 Common Hazardous Wastes Inorganic – minerals Carbon 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, H 2 –Overlap of orbitals

5 Common 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)

6 Common 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

7 Common 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)

8 Common Hazardous Wastes Isomerism – The different ways to write chemicals: Empirical formula – glucose, CH 2 O, ratio of the elements in the molecule Chemical formula – C 6 H 12 O 6, number of each atom in the molecule Structural formula – drawing of the compound with straight lines representing the bond

9 Common 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

10 Common 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

11 Common 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

12 Common Hazardous Wastes NumberName 1Methane 2Ethane 3Propane 4Butane 5Pentane 6Hexane 7Heptane 8Octane 9Nonane 10Decane 11Undecane 12Dodecane 13Tridecane 14Tetradecane 15Pentadecane 16Hexadecane 17Heptadecane 18Octadecane 19Nonadecane 20Eicosane

13 Common 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 -CH 3 Methyl -CH 2 -CH 3 Ethyl – Table 2.3 Common Alkyl Groups

14 Common Hazardous Wastes IUPAC Nomenclature for Alkanes 1. Select the carbon skeleton with the longest chain as the parent compound 2. Assign numbers to the carbons where the alkyl group is attached 3. 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

15 Common 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

16 Common 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

17 Common Hazardous Wastes Rules for naming Alkenes 1. 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

18 Common 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

19 Common 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)

20 Common 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

21 Common Hazardous Wastes PAH Nomenclature Rules 1. 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

22 Common 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 10 9 barrels/year – Used in auto’s, heating, power generation, etc.

23 Common 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

24 Common Hazardous Wastes Four classes of PAH’s in Crude oil: – Parafins – alkanes – Olefins – alkenes – Napthenes – cycloalkanes – Aromatics – monocyclic aromatic hydrocarbons and PAH’s

25 Common 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

26 Common 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

27 Common 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.

28 Common 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

29 Common 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

30 Common 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

31 Homework Chapter 2: 1, 3, 4, 5, 8


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