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 in specific ways – depends on type functional group added Intermolecular Forces • Determine Boiling Point & Solubility • Van der Waals or dispersion: weakest – nonpolar molecules • Dipole-dipole: intermediate strength – molecule has atoms with different electronegativities – atoms not arranged symmetrically • 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 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 Naming Halides • figure out backbone name • prefixes specify substituent: fluoro, chloro, bromo, iodo • use di, tri, tetra – if more than one same thing • tell location(s) of halogen(s) – state # C attached to in backbone 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 • # C’s so lowest number 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 intermolecular forces • CH4: bp = -162C density = 0.423 g/ml • CH3Cl: 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 • 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 Table R • General Formula halocarbons: R-X – R represents entire hydrocarbon part of molecule – X represents halogen (F, Cl, Br, or I) Alcohols • OH group replaces H in hydrocarbon • OH group called: hydroxyl group H HCH H OH H HCOH H Alcohols are non-electrolytes! • hydroxyl group = hydroxide ion of bases - does not form ions in water! • hydroxyl group is polar – alcohols soluble in water Naming AlcohOLs • Based on alkane name • Name parent chain – drop –e ending & add –ol • If parent chain has 3+ C’s, # which C OH group(s) attached to 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 • Prefixes di-, tri-, tetra– used before -ol ending – tell # of hydroxyl groups Classifying Alcohols • By # of hydroxyl groups –Monohydroxy: 1 hydroxyl group –Dihydroxy: 2 OH groups –Trihydroxy: 3 OH groups • By position of each hydroxyl group on main carbon chain Monohydroxy Alcohols • Primary: OH group attached to end C of chain or branch • Secondary: OH group attached to chain C bonded to 2 other C’s • Tertiary: 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 Table R • General Formula Alcohols: ROH • R represents entire hydrocarbon part of molecule • OH is hydroxyl group 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 – bent, like H2O • Ethyl ether once used as anesthesia Properties of Ethers • Compared to alkanes (same # C’s): – Higher bp’s than similar alkanes – More soluble in water than alkanes • Compared to alcohols (same # C’s): – Lower bp’s than similar alcohols – Much less soluble in water than alcohols Naming Ethers • If both hydrocarbon branches are identical: – name the branch (once) & add the word ether • If 2 branches are different: – list them in alphabetical order followed by the word ether H H HCOCH H H Methyl Ether 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