Alcohol Derivatives - Amines

Amines are a very interesting group of weak bases. They have very similar properties to ammonia.

Different sources quote different ways of preparing amines. Most sources quote that amines are made by reacting ammonia with a haloalkane. This would make an acid (hydrogen halide, such as HCl) and a base (the amine). These would react to make an amino salt. You would need excess ammonia and/or high temperature (to drive off the hydrogen halide) for an aqueous solution of the amine to truly be produced. Please keep this in mind when looking at the video and other sources.

For more information, please click HERE (ChemGuide)

Alcohol Derivatives - Haloalkanes

Haloalkanes are a very useful intermediate compound, often used when converting one useful compound into another. Their own uses are limited, primarily due to the impact they have on the environment. Haloalkanes are generally immiscible (insoluble in water) as they are (technically) non-polar.

Haloalkanes are the products of:

• reacting a halogen (such as bromine) with hydrocarbons.
• reacting an alcohol with Lucas Reagent (chloroalkanes produced); remember that tertiary alcohols react very quickly, while primary alcohols may not react at all.
• reacting an alcohol with PCl₃, PCl₅ or SOCl₂

Haloalkanes can be converted into:

• alkenes, using NaOH (or KOH) dissolved in alcohol (elimination reaction)
• alcohols, using aqueous NaOH (or KOH) (substitution reaction)
• amines, using excess NH₃ (substitution reaction); if you use do not use enough NH₃, it will make an amino salt instead, such as ethyl ammonium chloride

For more information about haloalkanes, click HERE (ChemGuide)

Alcohol Derivatives - Carboxylic Acids

Carboxylic acids are made when primary alcohols are oxidised under reflux. They are weak acids, as they do not completely dissociate in water. This means that they have a lower hydronium ion concentration that inorganic acids, like hydrochloric acid, so have a higher pH (but still below 7) and slower reaction rate.

For more information about carboxylic acids and their reactions, click HERE (ChemGuide)

Reactions of Alcohols

Today, we did some experiments with primary, secondary and tertiary alcohols. There was no teaching done today, so here are some videos explaining some of our observations and how to use them to identify/classify alcohols.

Preparation of Butanol from Butene

There are a few ways to make alcohols:

• fermentation of sugars
• synthesis gas
• hydration of alkenes

We looked at the hydration of 1-butene using dilute sulfuric acid:

Isomers of Pentanol

We had to try to make and name as many isomers of pentanol as we could (using molecular models):

Some of the numbering in these is redundant, but it is a good habit to include them at this stage.

The Structure of Alcohols

The structure of alcohols tells us a lot about their physical properties and chemical reactions. This lesson was about the different isomers of C₄H₉OH, with the students starting by trying to make (and name) all of the ones that contain the alcohol functional group.

EXTENSION (not covered in Level 2, but worth seeing if you disagree about your structures of 2-butanol you made in class)