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Ch. 11: Carbon A Multifarious Element Why Carbon? • Versatility • Single, double, triple bonds • Structural diversity Short-hand for expressing carbonbased compounds • C4H10: butane • Structural formula • Condensed structural formula • Carbon skeleton formula • C4H8 • C4H6 Isomers • Isomers – same composition, diff. structures • Structural isomers: same # atoms, diff. structures Ethanol (C2H6O) vs. dimethylether (C2H6O) Problems • Draw all isomers of C3H8O. There are 3. • Draw all isomers of C4H8Br2. There are 9. Stereoisomers • Same formula, diff. orientation • Two types: • 1) geometric • 2) optical isomers Geometric isomers • Require double bond! • Cis vs. trans Optical isomers • Nonsuperimposable mirror images • Called chiral molecules (chirality) • Pairs of chiral molecules = enantiomers Classes of Carbon-Containing Cmpds • Hydrocarbons • Only C & H • Alkane: CnH2n+2 • (Saturated every C-C bond single) • Alkene: CnH2n (at least one double bond btwn C’s) • (Unsaturated double, triple bonds) Classes of Carbon-Containing Cmpds • Alkyne: CnH2n-2 (at least one triple bond btwn C’s) • Cyclohydrocarbons: rings of carbon • Aromatic: rings w/pi-bonding – benzene Naming Alkanes • Suffix: -ane • Count out longest carbon chain • Prefixes: • 1C meth• 2C eth• 3C prop• 4C but• 5C pent• 6C hex• 7C hept• 8C oct• 9C non• 10C dec- Naming Alkanes • Hydrocarbon substitution = alkyl groups • Meth methyl, etc. • Use number, followed by “-”, to designate placement of substituent – 2-methylpentane • If 2 or more of same subs. di, tri, tetra, etc. – 2,3-dimethylpentane • If more than one different alkyl group, use alphabetic ordering – Butyl precede ethyl precedes methyl • 4-ethyl-3-methylheptane • In naming hydrocarbons always go with longest carbon-chain Draw out the following alkanes and rename them, if needed • Hexane • 2-methylhexane • 2,2-diethylpropane • 4-ethyl-2-methylnonane • Now, I’ll draw some and you name them Naming Alkenes, alkynes • Start counting carbon chain from lowest carbon containing double/triple bond • 1-propene, not 2-propene • Use number, followed by “-”, to designate placement of double or triple bond – 1-butene – 2-octyne Draw the following and if there is isomerism draw both structures and name them • 1-hexene • 2-hexene • 3-heptyne • 2-methyl-3-heptyne • Now, I’ll draw some and you name them Naming Halohydrocarbons • Same rules apply – – – – – In alphabetical order Bromine bromo chlorine chloro fluorine fluoro iodine iodo • Ex: 2-chlorobutane • • • • Practice (fix if necessary): 3-bromo-2-chloropentane 3,3-diiodobutane Now, I’ll draw some and you name them Naming Aromatic Cmpds • Monosubstitution: – Methylbenzene toluene – Phenol – Aniline • Disubstitution: • o- = ortho • m- = meta • p- = para Practice • Chlorobenzene (does it make a difference where you put the Cl?) • Draw all isomers (and name them) of a benzene that has 1 bromine and one fluorine – Which combinations are disallowed and why? Other functional groups • Functional group = characteristic grouping or arrangement of atoms • Alcohols = R-OH • Methanol, ethanol, propanol, etc. • Structural isomers of alcohols • 1,2-ethanediol = ethylene glycol Practice: rename if necessary • 1-propanol • 2-propanol • 3-propanol • Now, I’ll draw some and you name them Other functional groups • Ether: ROR’ 1) Select the longest carbon chain and name it as the correct alkane. 2) Change the “-yl” ending of the other (shorter) hydrocarbon group to “-oxy” to obtain the alkoxy group name. 3) Combine the two names giving the alkoxy group name first. Practice • Dimethylether • Butoxyhexane • methoxyethane • Now, I’ll draw some and you name them Other functional groups • Amines • RNH2 • Putrescine = 1,4-butanediamine • Cadaverine = 1,5-pentanediamine Practice • Triethylamine • Triisopropylamine • Now, I’ll draw some and you name them Other functional groups • • • • Aldehydes RCOH Start counting the carbon-chain from the C=O Methanal, butanal, hexanal • • • • Ketones RCOR’ Start counting the carbon-chain from the C=O 2-propanone, 3-heptanone Practice • Methanal • Hexanal • 2-pentanone • 4-decanone • Now, I’ll draw some and you name them Other functional groups • • • • Carboxylic acids RCOOH Start counting the carbon-chain from the C=O Methanoic acid, ethanoic acid, etc. • • • • • • • Esters RCOOR’ Start counting the carbon-chain from the C=O -OR’ takes on alkyl name RCO takes on –oate suffix Thus, HCOOCH3 methyl methanoate By the way, acetate = ethanoate Practice • • • • • Hexanoic acid 2-methylpropanoic acid (give its other name) Hexyl ethanoate Butyl butanoate 3-methylbutyl ethanoate (has a more common name) • Now, I’ll draw some and you name them Other functional groups • Amides • RCONR2 • Ex: methanamide, ethanamide Polymers • Huge molecules with repeating monomers • • (subunits) Thermoplastics (polyethylene, styrofoam): respond to heating Soften and flow when heated, harden when cooled; reversible – Over 60 million tons of polyethylene produced annually! • Thermosetting plastics (Formica-brand): initially soft, but solid when heated; irreversible Styrofoam, Teflon, silicone, Kevlar Condensation Polymers • Combining monomers and splitting out small molecules (like water) – Demo • Making nylon • Demo – Green “snot” Green “snot” Copolymers • Polymerization of 2 • (or more) diff. monomers Such as: – Styrene-butadiene rubber (SBR) • Predominately used for car and light-truck tires