Preparation of Aldehydes and ketone

Introduction

Aldehyde and ketone is an organic compound that both have C=O or carbonyl group. The different between aldehyde and ketone is that, aldehyde have alkyl (R) group and one hydrogen (H) atom attached to it C=O, or carbonyl group. While ketone have two alky (R) group to attached to it C=O or carbonyl group without H atom.

In some case, potassium dichromate (K₂Cr₂O₇) is used for oxidizing agent, the reaction are usually carried out in an acidic solution such as tetraxosulfate (IV) acid (H₂SO₄)(aq).

In the above, it shown that determination of further oxidation of ketone is not predictable. Now with the explanation, and illustration with above diagram, you have understand equation governing the production aldehyde and ketone. Example of ketone, is acetone. Acetone is one of the common and simplest of ketone, with (IUPAC name, 2-propanone), is commercially used as a paint thinners and nail polish removers.  Acetone product in the laboratory production usually purified by distillation process, we shall throw more light on acetone distillation as we progress with our studies.

Physical properties

The contain polar carbonyl group, as a result of this make aldehyde and ketone a polar compounds, but the cannot form hydrogen with one another as the alcohol usually do, as such aldehyde and ketone have lesser boiling point compare to alcohol that have the same molecular weight, but higher compare to those of hydrocarbon of the same molecular weight. They have a significant solubility in water (H₂O) if they contain carbons less than five, the reason is because of the formation of hydrogen bonds with water molecules.  Acetaldehyde (ethanal, CH₂CHO) and acetone are water miscible in all proportions.

Chemical Properties

There are little similarity between aldehyde and ketone, aldehyde are easily oxidized, this occur as result as of the hydrogen atom attached to the carbonyl group. While in ketone there are no hydrogen attached to the carbonyl group of I, which make it less oxidized.

Aldehyde reaction with other element to produce carboxylic acid, even can oxidized aldehyde, as shown below;

Some other weak oxidizing agent can also result this reaction,. One of this is Tollens reagent, a (HO^–) solution of complex ion silver Ag(NH₃)⁺. The reaction give a product of metallic silver (Ag⁰), that often produce shiny mirror on the container side.

laboratory preparation of ester 

Present of aldehyde is detected with the use of Tollens reagent. Bededicts reagent solution can also be oxidize to aldehydes. The solution is made up of basic (OH^-) solution of copper (II) citrates. Which the simple formula cannot be represented by complex composition.

On the above equation it found that is conversion of copper blue (II) citrate to an insoluble red copper (I) oxide. This conversion indicate a positive test. The reaction did not only take place in a simple aldehyde but also reducing sugar, example glucose.