Hydrocarbon Derivatives: Halocarbons Alcohols Ethers Hydrocarbons • contain only carbon & hydrogen • carbon can also form strong covalent bonds with other elements such as: O, N, F, Cl, Br, I, S, & P Functional Group • functional group: atom or group atoms in organic molecule that always behaves the same way • adding functional group changes chemical & physical properties of molecule in specific ways – changes depend on type functional group added Intermolecular Forces • determine boiling point & solubility • van der Waals (dispersion): weakest – nonpolar molecules • dipole-dipole: intermediate strength – molecule has atoms with different electronegativities – molecules not symmetrical • hydrogen bonding: strongest – molecules contain H bonded to F, O, or N Functional Groups 1. halocarbons 2. alcohols 3. ether 4. aldehydes 5. ketones 6. carboxylic acid 7. ester 8. amines 9. amide 10.amino acid see Table R Halocarbons/Halogens/ Organic Halides • one (or more) hydrogen atoms in alkane is replaced with halogen atom (F, Cl, Br, or I) • no longer hydrocarbons! • called halocarbons, alkyl halides or organic halides Table R • general formula halocarbons: R-X – R represents entire hydrocarbon part of molecule – X represents halogen (F, Cl, Br, or I) Naming Halides • figure out backbone name • prefixes specify halogen: fluoro, chloro, bromo, iodo • di, tri, tetra if more than one same halogen • state # C attached to in backbone – gives location(s) of halogen(s) 0 Note: follow same basic rules learned so far • # chain so halogen has lowest # • halogen # takes precedent over multiple bonds and branches CH3Cl H H–C–Cl H chloromethane CH3CHFCH3 H H H H–C–C–C–H H F H 2-fluoropropane C3H7F Naming Halides CH3CCl2CHClCH3 H Cl H H H–C–C–C–C–H H Cl Cl H 2,2,3-trichlorobutane C4H7Cl3 Ranking Halogens • if more than 1 kind halogen atom present – name them alphabetically • lowest # goes to halogen alphabetically first • Different Halogens 4 3 2 1 chlorine 1st alphabetically: determines numbering 2-chloro-4-fluoro-3-iodobutane Name: Br CH3CH2CHCHCH3 I 3-bromo 2-iodo pentane F Cl HCCH F Cl 1,1-dichloro-2,2-difluoroethane Properties of Halocarbons • alkane & alkyl halide of similar size & shape: – alkyl halide has higher bp & higher density Why? stronger IMF • CH4: hydrocarbon (non-polar) bp = -162C density = 0.423 g/ml • CH3Cl: halogen (polar) bp = -24C density = 0.911 g/ml CH3CH2CH2CH2CH3 pentane CH3CH2CH2CH2CH2F 1-fluoropentane CH3CH2CH2CH2CH2Cl 1-chloropentane CH3CH2CH2CH2CH2Br 1-bromopentane CH3CH2CH2CH2CH2I 1-iodopentane Boiling Point (C) 36 Density (g/ml) 0.626 63 0.791 Inc 108 0.882 130 1.218 155 1.516 Inc Uses of Alkyl Halides • cleaners, solvents, plastics • examples: – Teflon & PVC’s – refrigerants (used to be chlorofluorocarbonsnow hydrofluorocarbons) Halogen Derivatives • CH3Cl: local anesthetic (chloromethane) • CHCl3: solvent, general anesthetic (trichloromethane) • CHI3: antiseptic (tri-iodomethane) • CCl4: dry cleaning solvent (tetrachloromethane) • CF2Cl2: refrigerant (dichloro,difluoromethane) • fluorocarbons: teflon, lubricants, synthetic blood • chlorofluorocarbons: aerosol propellants, refrigerants Alcohols • OH group replaces H in hydrocarbon • OH group called hydroxyl group H HCH H OH H HCOH H Table R • general formula Alcohols: ROH • R represents entire hydrocarbon part of molecule • OH is hydroxyl group alcohols are non-electrolytes! • hydroxyl group (hydroxide ion of bases) - does not form ions in water! (no metal like bases) • hydroxyl group is polar – alcohols soluble in water Naming AlcohOLs • based on alkane name • name parent chain – drop –e ending & replace with –ol • # C OH group(s) attached to (if 3+ carbons) Naming H H H H HCCCCH OH H H H 1-butanol bp = 100C H H H H HCCCCH H OH H H 2-butanol Bp = 115C Note: never more than one OH group per C more than 1 hydroxyl group • use prefixes di-, tri-, tetra– put before -ol ending – tell # of hydroxyl groups Classifying Alcohols 1. by # of hydroxyl groups 2. by position of each hydroxyl group on main carbon chain # hydroxyl groups • monohydroxy alcohol: 1 hydroxyl group • dihydroxy alcohol: 2 OH groups • trihydroxy alcohol: 3 OH groups position of hydroxyl group: monohydroxy alcohols • primary alcohol: -OH group attached to end C of chain • secondary alcohol: -OH group attached to C bonded to 2 other C’s • tertiary alcohol: -OH group attached to C at branch point (C bonded to 3 other C’s) HHHH H-C-C-C-C-O-H HHHH HHHH H-C-C-C-C-H HHO H H 1-butanol (primary) 2-butanol (secondary) H H-C-H H H H-C-C-C-H HO H H 2-methyl 2-propanol (tertiary) H H H-C─C-H O O H H H H H H-C─C─C-H O O O H H H dihydroxy trihydroxy Properties of Alcohols • contain: H bonded to O atom – hydrogen bonding • alcohols: higher bp than corresponding alkane • ‘like dissolves like’ – alcohols tend to be very soluble in water R R - O H + O H H-bond + - Which compound has the highest boiling point? A. B. C. D. CH4 C 2H 6 C 3H 8 C3H7OH Correct response = D Ethers • general formula ROR – where R may or may not be same as R • R and R are hydrocarbon branches • O is oxygen bridge • ethers are not linear – they are bent, like water Properties of Ethers • pure ether: no hydrogen bonding – weak dipole-dipole interactions since polar – bent, like H2O • ethyl ether once used as anesthesia Properties of Ethers • compared to alkanes with same # C’s: – higher bp’s than alkanes (ethers have greater mass due to O) – more soluble in water than alkanes (ethers are polar, alkanes are not) • compared to alcohols with same # C’s: – lower bp’s than similar alcohols (ethers don’t have H-bonds, alcohols do) – much less soluble in water than alcohols (ethers less polar than alcohols) Naming Ethers • if both hydrocarbon branches identical: – name branch only once followed by ether • if 2 branches are different: – list names alphabetically followed by ether H H HCOCH H H methyl ether (correct on Table R) H H H H H H HCCCOCCCH H H H H H H propyl ether H H H H HCOCCCH H H H H methylpropyl ether