Synthesis of 9, 10-dihydroanthracene-9, 10-endo-α, β-succinic anhydride from anthracene

5/5 - (2 votes)

[ps2id id=’background’ target=”/]

BACKGROUND

Principle: The reaction of conjugated dienes with the ethylenic or acetylenic compound to form a six member cyclic product commonly known as “adduct” and reaction is known as Diels- Alder reaction. It is [4+2] cycloaddition involving reaction of diene (4π electrons) with dienophile (2π electrons) to form cyclic product. This is an example of pericyclic or concerted reaction, where all the bond formations and bond breaking occur at the same time. In the same fashion anthracene (diene) reacts with maleic anhydride (dienophile) to give 9, 10-dihydroanthracene – 9, 10 – endo – α, β – succinic anhydride.¹

Aim: To synthesize 9, 10 – dihydroanthracene – 9, 10 – endo – α, β-succinic anhydride from anthracene (Diels-Alder reaction).

Reaction:

Mechanism:
Cyclo-addition reaction (Diels-Alder reaction) or Pericyclic reaction

[ps2id id=’requirements’ target=”/]

REQUIREMENTS

Chemicals: Anthracene

Maleic anhydride

Xylene

Activated charcoal

Apparatus: Beaker

Pipette

Round bottom flask – 250 ml

Condenser

Glass rod

Buchner funnel

[ps2id id=’procedure’ target=”/]

PROCEDURE

Transfer 4 g of anthracene, 2.2 g maleic anhydride and 50 ml of dry xylene in a 250 ml round bottom flask fitted with a reflux condenser. Boil the reaction mixture for about 30-35 min. under reflux and then allow it to cool down to room temperature. If the reaction mixture appears to be colored, add 1 g of finely powdered activated charcoal and again reflux for 10-15 min. Filter the hot solution through Buchner funnel with suction and on subsequent cooling, in the filtrate colorless crystals of product (also known as adduct) are obtained. The yield of the crude product is 4.3 g, having melting point 256-258 ͦ C. Recrystallize the crude product from about 50 ml of xylene, filter the hot solution through small preheated funnel, allow to cool the filtrate, so that solute soon crystalline out. Recrystallized product is obtained as colorless crystals, melting point 260-263 ͦ C, with yield of 4.1 g.

Calculation:

Here limiting reagent is anthracene; hence yield should be calculated from its amount taken.

Molecular formula of anthracene = C₁₈H₁₀

Molecular formula of 9,10–dihydroanthracene-9,10–endo-α,β-succinic anhydride = ‎C₁₈H₁₂O₃

Molecular weight of anthracene = 178 g/mole

Molecular weight of 9,10–dihydroanthracene-9,10–endo-α,β-succinic anhydride = 276 g/mole

Theoretical yield:

178 g anthracene forms 276 g product

Therefore, 4 g anthracene will form …….? (X) g product

X =( 276 ×4)/178 = 6.2 g

Theoretical yield = 6.2 g

Practical yield = ————- g

% Yield = (Practical Yield)/(Theoretical Yield) × 100

[ps2id id=’conclusion’ target=”/]

CONCLUSION

9,10–dihydroanthracene-9,10–endo-α,β-succinic anhydride was synthesized and the percentage yield was found to be………..%

[ps2id id=’references’ target=”/][ps2id id=’1′ target=”/]

REFERENCES

Practical in organic chemistry, by Hitesh G. Raval, Sunil L. Baldania and Dimal A. Shah, Nirav Prakashan, Page no. 275.