1 / 31

Lecture 3

Lecture 3. Hazardous Waste – Chapter 2. Common Hazardous Wastes. Most common classes of hazardous compounds: Petroleum products Solvents Pesticides Polychlorinated biphenyls Dioxins Metals. Common Hazardous Wastes. Need to learn the language of Haz Waste

charlotte
Download Presentation

Lecture 3

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

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, H2 • 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, 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

  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 • International Union of Pure and Applied Chemists (IUPAC) • Common and Trivial Names • 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

  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 • -CH3 Methyl • -CH2-CH3 Ethyl • Table 2.3 Common Alkyl Groups

  14. Common Hazardous Wastes • IUPAC Nomenclature for Alkanes • Select the carbon skeleton with the longest chain as the parent compound • Assign numbers to the carbons where the alkyl group is attached • 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 • Commas always separate numbers and hyphens always separate words • 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 • The longest carbon skeleton containing the double bond serves as the basis for naming the compound, -ene suffix instead of –ane • Number the first double-bonded carbon on the longest chain so that it has the lowest possible # • Name alkyl substituents in the same manner as alkanes • 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 • Draw the PAH rings so that two of the sides are vertical • Draw as many rings as possible in a horizontal line • 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 109 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

More Related