Please enable JavaScript.
Coggle requires JavaScript to display documents.
Chapter 15 - Haloalkanes, image, image, image, image, image - Coggle…
Chapter 15 - Haloalkanes
Naming
Haloalkanes - compounds containg carbon, hydrogen and atleast one halogen
When two or more halogens are present, in a structure they are listed in alphabetical order
Haloalkane reactivity
Haloalkanes have a carbon-hydrogen bond, halogen atoms are more electronegative than carbon atoms
Electron pair in carbon-halogen bond is closer to the halogen atom than the carbon atom, so the bond is polar
In haloalkanes the carbon atom has a slightly positive charge and can attract species containing a lone pair
Nucleophile include: hydroxide ions, water molecules and ammonia molecules
Electronegativity decreases down the group meaning the carbon-fluorine bond is much more polar the carbon iodine bond, so the C-I bond is much weaker
-
Hydolysis
Chemical reaction involving water or an aqueous solution of a hydroxide that causes the breaking of a bond in a molecule
In hydrolysis of a haloalkane, halogen atom is replaced by an -OH gropu
Process
1) Nucleophile, OH- approaches the carbon atom attatched to the halogen on the opposite side of the molecule from the halogen
2) Angle of attack by the OH- minimises repulsion between the nucleophile and the halogen (dipole negative)
-
-
-
-
Haloalkanes can be converted to alcohol using aqueous sodium hydroxide, the mixture is heated under reflux
-
-
Experiment
-
-
3) Place a test tube with 0.1 moldm3 of silver nitrate in the water bath and allow it to reach the same temperature as the other tubes
-
-
-
Hydrolysis of primary, secondary and tertiary haloalkanes
-
Primary haloalkane reacts with a one-step mechanism, whereas a tertiary haloalkane reacts by a two-step mechanism
1st step - carbon-halogen bond of the tertiary haloalkane breaks by heterolytic fission, forming a tertiary carbocation and halide ion
-
Increased rate is due to the increased stability of the tertiary carbocation compared to the primary carbocation
-
-
-
-
-
-
