Commercial Uses of Propylene H3 H CH3 H.C-CH-CH3 Ag cat. polymerize H H H H propylene oxide propylene polypropylene H+ HO catalyst 0 CH2-CH-CH3 CH3-CH-CH3 cat. CH3-C-CH3 OH OH OH propylene glycol isopropyl alcohol acetone Copyright 2010 Pearson Prentice Hall,Inc
Commercial Uses of Propylene
Addition Polymers H CH3 H CH3 H CH3 H-C-CH CH3 polymerize H H H nH H propylene (monomer) polypropylene (polymer) H CI H CC=C polymerize H H H H H H」n H H vinyl chloride poly(vinyl chloride) PVC,“vinyI' polymerize tetrafluoroethylene poly(tetrafluoroethylene) PTFE,Teflon® Copyright 2010 Pearson Prentice Hall,Inc
Addition Polymers
Physical Properties Low boiling points,increasing with mass. Branched alkenes have lower boiling points. Less dense than water. Slightly polar -Pi bond is polarizable,so instantaneous dipole- dipole interactions occur. -Alkyl groups are electron-donating toward the pi bond,so may have a small dipole moment
Physical Properties ❖Low boiling points, increasing with mass. ❖Branched alkenes have lower boiling points. ❖Less dense than water. ❖Slightly polar ◼Pi bond is polarizable, so instantaneous dipoledipole interactions occur. ◼Alkyl groups are electron-donating toward the pi bond, so may have a small dipole moment
Physical Properties Polarity Similar to alkanes,haloalkanes. H CH3 u=0.33D 3=9 u=0 cis-2-butene,bp 4 C trans-2-bute ne,bp 1 C C=0 H H H u=1.7D 4=0D b.p.=60°c b.p.=48°c
Physical Properties Similar to alkanes, haloalkanes. Cl C H C H Cl Cl C H C Cl H m = 1.7 D b.p. = 60ºc m = 0 D b.p. = 48ºc Polarity m = 0.33 D cis-2-butene, bp 4 °C C C H H3C H CH3 m = 0 trans-2-butene, bp 1 °C C C H H H3C CH3
Stability of Alkenes Measured by heat of hydrogenation: Alkene H2->Alkane energy More heat released,higher energy alkene. difference 2.7 kcal (11 kJ) 30.3kcal(127kJ) 27.6 kcal (115 kJ) reaction coordinate
Stability of Alkenes ❖Measured by heat of hydrogenation: Alkene + H2 → Alkane + energy ❖More heat released, higher energy alkene