Presentation on theme: "Interactions of Hazardous Materials This presentation was prepared to provide some background or refresher notes on selected & limited topics in beginning."— Presentation transcript:
Interactions of Hazardous Materials This presentation was prepared to provide some background or refresher notes on selected & limited topics in beginning 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. References: Meyer, E. (2010). Chemistry of Hazardous Materials. (5 th edition). NJ: Pearson Kotz, J.C. et al (2003). Chemistry & Chemical Reactivity. (5 th edition). USA: Thomson Learning Pine, S.H. et al (1989). Organic Chemistry, (4 th edition). NY: McGraw-Hill Intro to Organic Chemistry Prepared by: Dolores Gough, P.E. George Gough, P.E., CSP
Basic Features of Atoms (review from Unit 1 PP presentation) Atom: smallest particle of 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 Nucleus P+ N e -- Protons and neutrons reside within the nucleus Electrons reside in designated regions surrounding the nucleus called atomic orbitals
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) 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 ). 6 P 6 N Atomic Structure of Carbon -
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 or CH 4 (methane) H 1 P 0 N Atomic Structure of Hydrogen - Hydrocarbons (HC) are compounds whose molecules consist of only carbon and hydrogen atoms.
Carbon – Carbon Single Bond: Alkanes: have general formula of C n H 2n+2 where n = number of carbon atoms Example: Butane has 4 carbons, all single bonds as shown: H H H H I I I I H - C - C – C - C - H C 4 H 10 (see Table 12.1) I I I I H H H H 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 B) Carbon = Carbon Double Bond: Alkenes or Olefins: have general formula of C n H 2n Example: Butene has 4 carbons and at least 1 double bond H H H H I I I I H - C - C = C - C – H or H – C = C – C – C - H I I I I I I I H H H H H H H C 4 H 8
Carbon Ξ Carbon Triple Bond: Alkynes: have general formula of C n H 2n-2 Example: Butyne has 4 carbons and at least 1 triple bond H H H H I I I I H - C - C Ξ C - C – H or H – C ΞC – C – C - H I I I I H H H H C 4 H 6 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 are 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 525) for common alkyl substituents ) Rules for naming an alkane (page 526) Example: CH 3 - CH 2 – CH - CH 2 - CH 3 I CH 3 3-methyl pentane
Aromatic Hydrocarbons: Regarded as compounds whose molecules are composed of one or more special rings of carbon atoms. Benzene – simplest aromatic hydrocarbon. C 6 H 6 Other common aromatic compounds: Toluene (or methylbenzene) Xylene 1,4 dimethyl benzene (para-xylene) 1,3 dimethylbenzene (meta-xylene) 1, 2 dimethylbenzene (ortho-xylene)
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: colorless solid having odor of mothballs; poses chronic respiratory hazard to humans; links exposure with onset of cancerous growths. Anthracene (C 14 H 10 ): component of coal-tar.
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 Let us take some examples: Functional group: hydroxyl (-OH) Class of organic compound: alcohol General formula: R-CH 2 -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 H – C – O – H or CH 3 OH (methanol) I H ,5 dimethyl 3-hexanol (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 CH 3 CH 2 - O - CH 2 CH 3 (ethyl) (ethyl)
Aldehydes and Ketones \ Both contain the carbonyl group C = O / Aldehydes - h ave carbonyl group located at end of chain of carbon atoms. Ketone -has carbonyl group located at nonterminal position within chain. Examples of aldehyde: formaldehyde or methanal (CH 2 O); acetaldehyde or ethanal (CH 3 CHO; 2-propenal or acrolein (CH 2 =CHCHO) Examples of ketone: acetone or 2-propanone (CH 3 COCH 3 ) methyl ethyl ketone or 2-butanone (CH 3 COCH 2 CH 3 )
Organic Acids Organic compounds containing the carboxyl group (-COOH); so they are also called carboxylic acids. They are weak acids; inherently corrosive, water-soluble with characteristic odors. General formula is R – COOH or 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): CH 3 COOH Propanoic acid (or propionic acid): CH 3 CH 2 COOH connected to cyclic structure: 2- hydroxybenzene carboxylic acid (or salicylic): o-HOC 6 H 4 COOH
Peroxo-Organic Compounds Organic hydroperoxides, organic peroxides Many compounds unstable Used to induce polymerization, process essential to production of plastics Source: Meyer (2010)
More details and other common hazardous organic chemicals are in the textbook