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Halocarbons, Alcohols, & Ethers. Hydrocarbon Derivatives:. 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 :
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Halocarbons, Alcohols, & Ethers Hydrocarbon Derivatives:
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
C3H7F CH3Cl CH3CHFCH3 H H H H–C–C–C–H HFH H H–C–Cl H 2-fluoropropane chloromethane
Naming Halides CH3CCl2CHClCH3 C4H7Cl3 HCl H H H –C – C – C – C– H HCl 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
2-chloro-4-fluoro-3-iodobutane Different Halogens 4 3 2 1 Chlorine 1st alphabetically: determines numbering
Br CH3CH2CHCHCH3 I 3-bromo 2-iodo pentane F Cl HCCH F Cl 1,1-dichloro-2,2-difluoroethane Name:
Stronger intermolecular forces Properties of Halocarbons • alkane & alkyl halide of similar size & shape: • alkyl halide has higher bp & higher density Why? • CH4: bp = -162C density = 0.423 g/ml • CH3Cl: bp = -24C density = 0.911 g/ml
Boiling Point (C) Density (g/ml) CH3CH2CH2CH2CH3 pentane 36 0.626 CH3CH2CH2CH2CH2F 1-fluoropentane 63 0.791 Inc Inc CH3CH2CH2CH2CH2Cl 1-chloropentane 108 0.882 CH3CH2CH2CH2CH2Br 1-bromopentane 130 1.218 CH3CH2CH2CH2CH2I 1-iodopentane 155 1.516
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)
OH H HCOH H H HCH H Alcohols • OH group replaces H in hydrocarbon • OH group called: hydroxyl group
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
H H H H HCCCCH OHH H H Note: Never more than one OH group per C Naming H H H H HCCCCH HOHH H 1-Butanol bp = 100C 2-Butanol Bp = 115C
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 H H H H 1-butanol (primary) H H H H H-C-C-C-C-H H HO H H 2-butanol (secondary)
H H-C-H H H H-C-C-C-H HOH 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 - O R - H O + H + H-bond
Correct response = D Which compound has the highest boiling point? • CH4 • C2H6 • C3H8 • C3H7OH
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
Methyl Ether Propyl Ether H H HCOCH H H H H H H H H HCCCOCCCH H H H H H H
Methylpropyl Ether H H H H HCOCCCH H H H H