SYNTHESIS OF CINNAMIC ACID BASED ON PERKIN REACTION USING SONOCHEMICAL METHOD AND ITS POTENTIAL AS PHOTOPROTECTIVE AGENT

Abstract

Cinnamic acid plays a vital role in the synthesis of other important compounds and as a precursor for
the synthesis of commercial cinnamon esters used in perfumery, cosmetics, and pharmaceutical
industries. The aim of this research is to synthesize cinnamic acid using sonochemical methods.
Cinnamic acid was synthesized using Perkin reaction by reacting 0.05 mole of benzaldehyde with
0.073 mole of acetic acid anhydride and 0.03 mole of sodium acetate as a catalyst in the Erlenmeyer
flask and then the mixture was put in a sonicator for 60 minutes at 70^oC. The synthesized compound
was tested organoleptic properties, and the melting point was measured. The chemical structure was
elucidated using FT-IR, H-NMR, and ¹³C-NMR. The photoprotective activity was examined from its
antioxidant and SPF values. The synthesized compound was found in the form of a shiny white fine
crystal which had distinctive odor with a yield of 4.98% and the melting point was found at 133^oC. In
the structure elucidation using FT-IR (the aromatic ring absorption at the wave number 1580 cm^-1-
1600 cm^-1. The wave number 1625 cm^-1 is an aromatic conjugated alkene group, while wave number
1689.4 cm^-1 is a carbonyl group. The wave number 2500 cm^-1– 3250 cm^-1 is an OH carboxylic acid
group) , H-NMR (7.410 (m, 5H, Ar-H); 7.425(t, 1H); 7.572 (d, 1H); 8.057 (d, 1H,C=CH) and ¹³C-NMR
(129.309 ppm; 130.998 ppm; 134.58 ppm; 170.017 ppm) showed that when compared with the
standard compound as the reference, the synthesized compound was confirmed to be cinnamic acid.
The antioxidant activity test showed that at the concentration of 20 ppm the synthesized compound
was able to reduce free radicals by 46.69%. This finding showed that the synthesized compound had
antioxidant activity.

Keywords: Cinnamic acid, Perkin Reaction, Photoprotective, Sonochemistry, Structure elucidation