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Chemistry- Chapter 14- Haloalkanes
Haloalkanes are the basis of many synthetic compounds such as PVC, teflon and a number
of solvents.
Haloalkanes have a hydrocarbon chain with one or more halogens in place of a hydrogen
atom, (i.e. F, Cl, Br, I)
General formula- CnH2n+1X (where X is the halogen).…

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Solubility

The polar C-X bonds are NOT POLAR ENOUGH TO MAKE THE HALOALKANE SOLUBLE IN
WATER.
Main intermolecular forces are van der Waals and dipole-dipole (no hydrogen bonds).
Haloalkanes can remove oily stains (oily stains are mixtures of hydrocarbons).


Boiling point

The boiling point of haloalkanes depends on the number…

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Nucleophilic Substitution

NUCLEOPHILE- Electron pair donor that attacks and forms covalent bonds with positively charged C
atoms. It is either a negative ion or has a slight negative charge.

E.g. -:OH (hydroxide ion), :NH3 (ammonia), -:CN (cyanide ion)



1. Nucleophilic substitution with aqueous NaOH (sodium hydroxide) or aqueous KOH (potassium…

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2. Nucleophilic substitution with cyanide ions (-:CN):




The product is called a "nitrile".

Note: When naming, include the new extra "C" in the root name followed by "nitrile.




3. Nucleophilic substitution with ammonia (NH3)

Conditions:

Reaction of haloalkanes with an excess of concentrated solution of ammonia (NH3) in ethanol
is…

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The product is a primary amine.

*NH3 must be added twice during this reaction.*




The uses of nucleophilic substitution:

RCH2X (Haloalkane)

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Elimination reactions in haloalkanes:

In theses haloalkane reactions, a hydrogen halide (H-X) is removed and a double (C=C) bond is left in
it's place, leaving an alkene.



1. The :OH- ion acting as a base

Although OH:- can act as a nucleophile, under different conditions it can act as a…

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1. The lone pair on the OH:- ion bonds with a H atom attached to one of the C atoms next to the C-X
bond. (H2O formed).

2. The electron pair from the C-H bond now becomes a C=C bond.

3. The X now takes the pair of electrons in…

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Haloalkanes and the environment:

Chlorofluorocarbons (CFC's) are haloalkanes containing only chlorine, fluorine and carbon (no
hydrogen).

CFC's are very unreactive under normal conditions.

Short chain CFC's are gases and used in aerosols, propellants, refrigerators etc.

Long chain CFC's are used as dry-cleaning and de-greasing solvents.

CFC's eventually end up in…

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This takes place in two stages:

Stage 1: The Cl* free radical takes a hydroen atom from CH4 (methane) to form hydrogen chloride, a
stable compound. This leaves a methyl free radical- CH3*

Cl* + CH4 --> HCl +CH3*

Stage 2- The methyl free radical reacts with a chlorine molecule,…

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