Ch. 11: Carbon A Multifarious Element

Ch. 11: Carbon A Multifarious Element

Why Carbon? Versatility Single, double, triple bonds Structural diversity

Short-hand hand for expressing carbon- based compounds C 4 H 10 : butane Structural formula Condensed structural formula Carbon skeleton formula C 4 H 8 C 4 H 6

Isomers Isomers same composition, diff. structures Structural isomers: same # atoms, diff. structures Ethanol (C 2 H 6 O) vs. dimethylether (C 2 H 6 O)

Problems Draw all isomers of C 3 H 8 O. There are 3. Draw all isomers of C 4 H 8 Br 2. 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( chirality) Pairs of chiral molecules = enantiomers

Classes of Carbon-Containing Containing Hydrocarbons Only C & H Cmpds Alkane: : C n H 2n+2 (Saturated every C-C C C bond single) Alkene: : C n H 2n (at least one double bond btwn C s) (Unsaturated double, triple bonds)

Classes of Carbon-Containing Containing Cmpds Alkyne: : C n H 2n-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 chain

Draw out the following alkanes and rename them, if needed Hexane 2-methylhexane 2,2-diethylpropane 4-ethyl-2-methylnonane Now, I ll I draw some and you name them

Naming Alkenes, alkynes Start counting carbon chain from lowest carbon containing double/triple bond 1-propene, not 2-propene2 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-heptyneheptyne Now, I ll I draw some and you name them

Naming Halohydrocarbons Same rules apply In alphabetical order Bromine bromo chlorine chloro fluorine fluoro iodine iodo Ex: 2-chlorobutane2 Practice (fix if necessary): 3-bromo-2-chloropentane 3,3-diiodobutane Now, I ll I 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-OHR 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 I 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 I draw some and you name them

Other functional groups Amines RNH 2 Putrescine = 1,4-butanediamine Cadaverine = 1,5-pentanediamine

Practice Triethylamine Triisopropylamine Now, I ll I draw some and you name them

Other functional groups Aldehydes RCOH Start counting the carbon-chain chain from the C=O Methanal, butanal, hexanalal Ketones RCOR Start counting the carbon-chain chain from the C=O 2-propanone,, 3-heptan3 heptanone

Practice Methanal Hexanal 2-pentanone 4-decanone Now, I ll I draw some and you name them

Other functional groups Carboxylic acids RCOOH Start counting the carbon-chain chain from the C=O Methanoic acid, ethanoic acid, etc. Esters RCOOR Start counting the carbon-chain chain from the C=O -OR takes on alkyl name RCO takes on oate suffix Thus, HCOOCH 3 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 I draw some and you name them

Other functional groups Amides RCONR 2 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 Demo Making nylon 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 truck tires