8Chapter 04

Dr wolfs chm 201 202 4 29 classificatio classificatio

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Unformatted text preview: r hydroxyl group. Dr. Wolf's CHM 201 & 202 4- 29 Classificatio Classificatio n n H CH3CH2CH2CH2CH2F OH primary alkyl halide secondary alcohol CH3 CH3CHCH2CH2CH3 Br secondary alkyl halide Dr. Wolf's CHM 201 & 202 CH3CCH2CH2CH3 OH tertiary alcohol 4- 30 4.5 Bonding in Alcohols and Alkyl Halides Dr. Wolf's CHM 201 & 202 4- 31 Dipole Moments Dipole Moments alcohols and alkyl halides are polar alcohols H H H δ+ C δ+ H H δ+ O δ– H C δ– Cl H µ = 1.7 D 1.7 Dr. Wolf's CHM 201 & 202 µ = 1.9 D 1.9 4- 32 Dipole Moments Dipole Moments alcohols and alkyl halides are polar alcohols µ = 1.7 D 1.7 Dr. Wolf's CHM 201 & 202 µ = 1.9 D 1.9 4- 33 Dipole-Dipole Attractive Forces Dipole-Dipole Attractive Forces Dr. Wolf's CHM 201 & 202 δ– δ+ δ– δ– δ+ δ+ δ– δ+ δ+ δ– 4- 34 Dipole-Dipole Attractive Forces Dipole-Dipole Attractive Forces Dr. Wolf's CHM 201 & 202 δ– δ+ δ– δ– δ+ δ+ δ– δ+ δ+ δ– 4- 35 4.6 Physical Properties of Physical Alcohols and Alkyl Halides: Alcohols Intermolecular Forces Boiling point Solubility in water Density Dr. Wolf's CHM 201 & 202 4- 36 Effect of Structure on Boiling Point Effect of Structure on Boiling Point CH3CH2CH3 Molecular weight Boiling point, °C Dipole moment, D Dr. Wolf's CHM 201 & 202 CH3CH2F CH3CH2OH 44 46 48 -42 +78 -32 0 1.9 4- 37 Effect of Structure on Boiling Point Effect of Structure on Boiling Point CH3CH2CH3 Molecular weight 44 Intermolecular forces are weak. Boiling point, °C Only intermolecular forces are induced dipole-induced dipole attractions. -42 Dipole moment, D Dr. Wolf's CHM 201 & 202 4- 38 Effect of Structure on Boiling Point Effect of Structure on Boiling Point CH3CH2F Molecular weight 48 Boiling point, °C -32 Dipole moment, D A polar molecule; therefore dipole-dipole and dipole-induced dipole forces contribute to intermolecular to attractions. attractions. 1.9 Dr. Wolf's CHM 201 & 202 4- 39 Effect of Structure on Boiling Point Effect of Structure on Boiling Point CH3CH2OH CH Molecular weight 46 Boiling point, °C +78 Dipole moment, D 1.7 Dr. Wolf's CHM 201 & 202 Highest boiling point; strongest intermolecular attractive forces. Hydrogen bonding is stronger than other dipole-dipole attractions. 4- 40 Figure 4.4 Hydrogen bonding in ethanol Figure 4.4 Hydrogen bonding in ethanol δ– δ– Dr. Wolf's CHM 201 & 202 δ+ δ+ 4- 41 Figure 4.4 Hydrogen bonding in ethanol Figure 4.4 Hydrogen bonding in ethanol Dr. Wolf's CHM 201 & 202 4- 42 Boiling point increases with increasing Boiling point increases with increasing number of halogens number of halogens Compound Boiling Point CH3Cl -24°C -24°C CH2Cl2 40°C 40°C CHCl3 61°C 61°C CCl4 77°C 77°C Even though CCl4 is the only compound in this list without a dipole moment, it has the highest boiling point. dipole Induced dipole-induced dipole forces are greatest in Induced CCl4 because it has the greatest number of Cl atoms. CCl Cl is more polarizable than H. Dr. Wolf's CHM 201 & 202 4- 43 But trend is not followed when halogen But trend is not followed when halogen is fluorine is fluorine Compound Boiling Point CH3CH2F CH3CHF2 -25°C -25°C CH3CF3 -47°C -47°C CF3CF3 Dr. Wolf's CHM 201 & 202 -32°C -32°C -78°C -78°C 4- 44 But trend is not followed when halogen But trend is not followed when halogen is fluorine is fluorine Compound Boiling Point CH3CH2F -32°C -32°C CH3CHF2 -25°C -25°C CH3CF3 -47°C -47°C CF3CF3 -78°C -78°C Fluorine is not very p...
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