'x' is the product which is obtained from benzene by reacting it with carbon monoxide and hydrogen chloride in the presence of cuprous chloride. 'y' is the major product obtained from the benzene by reacting it with ethanoyl chloride in the presence of anhydrous AlCl3. Product (major) obtained by heating x and y in the presence of alkali is z. Total number of π (pi) electrons in z is .
Answer
16
Solution
x: Gattermann–Koch reaction: C6H6 + CO + HCl anhyd. AlCl3/CuCl C6H5CHO (benzaldehyde)
y: Friedel–Crafts acylation: C6H6 + CH3COCl anhyd. AlCl3 C6H5COCH3 (acetophenone)
z: cross aldol (Claisen–Schmidt) condensation followed by dehydration:
C6H5CHO + CH3COC6H5 OH , C6H5CH=CH-CO-C6H5 (z)
[figure]
π electrons in z: two benzene rings = 2 × 6 = 12; C=C = 2; C=O = 2
∴ Total = 12 + 2 + 2 = 16
Answer: 16