Practical work on organic synthesis techniques

At the end of the organic chemistry practical work cycle, students should be able to:
- work in a laboratory in conditions of maximum safety for people (precautions with regard to chemical risks) and for the environment (waste recycling), in line with sustainable development and societal responsibility.
- properly implement an organic chemistry reaction and justify the experimental protocol followed to modify the structural/functional properties of a molecule.
- choose and implement a purification method suited to the physico-chemical characteristics of the compound synthesized. choose and implement a purification method adapted to the physico-chemical characteristics of the synthesized compound.
- choose and implement analysis and characterization methods adapted to the physico-chemical and structural characteristics of the synthesized product.
- interpret observations and explain the results obtained by writing reports.

Organic chemistry courses and practical work from previous years

Prior to the practical sessions, students will have 2 lesson slots dedicated to the theoretical foundations essential for the practical part.

These bases will cover :

- glassware and fixtures used in organic chemistry, depending on the reaction conditions to be set up.

- conducting a reaction

- the importance and role of end-of-reaction treatments.

The principle of purification methods will be recalled and analysis methods explained.

A reminder about personal protective equipment and safety conditions in the laboratory will be given.

Various reactions were selected for use during the practical sessions. Two 10-hour summaries, giving rise to TP reports, are carried out in pairs.

- synthesis of an organomagnesium, followed by nucleophilic addition of Grignard reagent to a carbonyl derivative.

- a reaction from Cannizzaro.

These reactions have been chosen to enable students to master the implementation of an organic reaction, taking into account not only the dangerousness of the reagents used and the products generated, but also their reactivity and physico-chemical characteristics (reaction under anhydrous conditions, for example). During these syntheses, students will acquire the skills needed to isolate compounds by liquid-liquid extraction, recrystallization, distillation under reduced pressure and steam distillation. They will also be able to characterize isolated products (infrared spectroscopy, melting point measurement, gas chromatography (GPC)) and assess their purity by GPC.

Finally, they will learn to write a report specific to organic synthesis laboratory work.

An individual assessment in which the student must synthesize an organic compound, purify it, characterize it and analyze its purity is used to evaluate these various skills. The synthesis to be carried out is chosen at random by the student. The reaction may involve nucleophilic substitution, aromatic electrophilic substitution, elimination, nucleophilic or electrophilic addition or transposition.

Molecular and Polymer Chemistry theme

"Organic Chemistry", K.P C. Vollhardt and N. E.Shore, Freeman and Co, New York, 1994