PREPARATION OF BENZOIC ACID + H2SO4 + H20 + ORGANIC CHEMISTRY SISP AIM: To prepare and submit benzoic acid from benzanilide APPARATUS: Round bottom flask, Reflux condenser, beaker, Funnel, Glass rod CHEMICALS: Benzanilide, 70%H 2 SO 4 PRINCIPLE: The principle involved in the preparation of benzoic acid from benzanilide is acid catalysed hydrolytic reation. Benzanilide undergoes hydrolysis in acidic medium to yield benzoic acid as colourless crystals. Aniline hydrogen sulphate being water soluble remains in solution and solid benzoic acid separates out. REACTION: PHARMACEUTICAL CHEMISTRY Page No.87 EXPERIMENT NO: 13
AIM: To prepare and submit benzoic acid from
benzanilideAPPARATUS: Round bottom flask, Reflux condenser, beaker,
Funnel, Glass rodCHEMICALS: Benzanilide, 70%H2SO4PRINCIPLE: The
principle involved in the preparation of benzoic acid from
benzanilide is acid catalysed hydrolytic reation. Benzanilide
undergoes hydrolysis in acidic medium to yield benzoic acid as
colourless crystals. Aniline hydrogen sulphate being water soluble
remains in solution and solid benzoic acid separates
out.REACTION:
+H2SO4+H20+ PROCEDURE: A mixture of 1 gm of benzanilide and 10
ml of 70%H2SO4 were placed in a round bottom flask fitted with a
reflux condenser. The mixture was boiled gently for 30 minutes.10ml
of hot water was poured on the inner walls of the condenser to
dissolve benzoic acid which gets solidified in the condenser. The
flask was cooled on ice bath. The benzoic acid separates. The solid
benzoic acid was filtered off, washed with cold water and
dried.Calculation: Molecular weight of salicylic acid
=138gMolecular weight of benzoic acid= 180g197 g benzanilide 122g
benzoic acid1 g benzanilide X g benzoic acidX=1*122/197=
0.6gTheoretical yield =0.6gPractical yield= -----------------
gPercentage yield = Practical yield/ Theoretical
yieldx100=------------------------------%w/wREPORT:Benzoic acid is
prepared and submitted.Theoretical yield of Benzoic acid
is-------------------------Practical yield of Benzoic acid is
-----------------------Percentage yield of Benzoic acid is
--------------------------%w/w.Question & Answers for Viva
Voce:1) What is the principle involved in the preparation of
benzoic acid from benzanilide?A) The principle involved in the
preparation of benzoic acid from benzanilide is acid catalysed
hydrolytic reation.2) Which compound on acid hydrolysis yields
benzoic acid?A) Benzanilide on acid hydrolysis yields benzoic acid
3) Give the molecular weight of benzoic acid?A) 1224) What is
hydrolysis?A) Hydrolysis is a chemical reaction during which the
bond is broken in a reactant by the addition of water.5)
Saponification is an example for which type of reaction?A)
Saponification is an example for base catalysed esterification
