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 Halocarbons Alcohols Ether Aldehydes Ketones Carboxylic Acid Ester Amines Amide 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 CH3CHFCH3 H H H H–C–C–C–H H–C–Cl H F H 2-fluoropropane         2-fluoropropane chloromethane C3H7F

Naming Halides 2,2,3-trichlorobutane CH3CCl2CHClCH3 C4H7Cl3 H Cl H H H – C – C – C – C – H H Cl Cl H 2,2,3-trichlorobutane

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 Chlorine 1st alphabetically: determines numbering 4 3 2 1 Chlorine 1st alphabetically: determines numbering 2-chloro-4-fluoro-3-iodobutane

Name: Br CH3CH2CHCHCH3 I 3-bromo 2-iodo pentane F Cl HCCH 1,1-dichloro-2,2-difluoroethane

Properties of Halocarbons alkane & alkyl halide of similar size & shape: alkyl halide has higher bp & higher density Why? CH4: bp = -162C density = 0.423 g/ml CH3Cl: bp = -24C density = 0.911 g/ml Stronger intermolecular forces

Inc Inc 1.516 155 CH3CH2CH2CH2CH2I 1-iodopentane 1.218 130 CH3CH2CH2CH2CH2Br 1-bromopentane 0.882 108 CH3CH2CH2CH2CH2Cl 1-chloropentane 0.791 63 CH3CH2CH2CH2CH2F 1-fluoropentane 0.626 36 CH3CH2CH2CH2CH3 pentane Density (g/ml) Boiling Point (C) Inc Inc

Uses of Alkyl Halides Cleaners & solvents Examples: Teflon & PVC’s Refrigerants (used to be chlorofluorocarbons- now 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 H H HCOH HCH OH group replaces H in hydrocarbon OH group called: hydroxyl group OH H HCOH H HC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 HCCCCH OH H H H H H H H HCCCCH H OH H H 1-Butanol bp = 100C 2-Butanol Bp = 115C 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)

H H H H H-C-C-C-C-O-H 1-butanol (primary) H H H H H-C-C-C-C-H H H O H H 2-butanol (secondary)

H H-C-H H H H-C-C-C-H H O H 2-methyl 2-propanol (Tertiary)

H H H-C─C-H O O 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 - O R - H O + H H-bond +

Which compound has the highest boiling point? C3H7OH Correct response = D

Table R General Formula Alcohols: ROH R represents entire hydrocarbon part of molecule OH is hydroxyl group

Ethers General formula ROR R and R are hydrocarbon branches 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 HCOCH Methyl Ether H H H H H H HCCCOCCCH Propyl Ether

H H H H HCOCCCH Methylpropyl Ether