Reaction #2: Cis-Trans Isomers Flashcards
Part 1: Cis-Trans Isomers
Weigh maleic anhydride
Heat DI water until boiling, add maleic anhydride
Cool, then place in ice
Vacuum filter solution, save filtrate
Part 2: Cis-Trans Isomers
Filtrate into round bottom flask, add HCl and boiling chips
Start condenser (water in bottom)
Boil and reflux for 10 min
Cool, ice bath
Vacuum filter
Weigh both crystals
Part 3: Cis-Trans Isomers
Use Meltemp to take a melting point
Test solubility by placing in separate test tubes with water
Why is maleic acid more soluble?
Maleic acid has a net dipole, so it is polar.
Why does fumaric acid have a higher melting point?
Fumaric acid can form two intermolecular hydrogen bonds, maleic acid can only form one, stronger IMF means higher melting points
What allows isomerism?
Double bonds allow for isomerism. If the double bond is moved, that bond is able to rotate, and then can be locked back into place with the double bond returning
How is fumaric acid produced?
- Maleic acid gains a proton from HCl
- Allows the delocalization of electrons, the double bond in the carbonyl group moves to the O
- Double bond between C2 and C3 moves towards the positive C
- Bond rotates
- Double bond returns
- Lone pair moves back between C and O
- Proton is removed
Hydrogen bonding
Strong interaction between a H bonded to O,N,F and a lone pair of e-
Net dipole
When a side of a molecule is more charged, creates polarity
Repulsion
How like charges avoid each other, negative e- clouds avoid each other
Steric interaction
How the shape of a molecule (nonbonding) influences the energy of the molecule
Rotation
Single bonds are able to turn freely
Delocalization
When lone e- don’t really “belong” to any one atom
If a molecule has more steric hinderance…
The molecule is less stable
What types of orbitals compose sp3 hybridization?
4 sp3 orbitals
What types of orbitals compose sp2 hybridization?
1 2p orbital and 3 sp2 orbitals
What types of orbitals compose sp hybridization?
2 2p orbitals and 2 sp orbitals
