Motiva Reaction Lab Report

Production diclofenac acid (DFA) by diclofenac sodium (DFS) hydrolysis

DFA which yielded from DFS hydrolysis was characterized by FT-IR and DTA. Fig. 2 showed the information provided by the spectra FT-IR profile, which distinguished DFS from DFA. The DFA’s spectra showed a specific absorption peak at 3324 cm-1 which correspond to free OH stretching of a carboxylic group. Free acid was also presented as a peak at 1693 cm-1 associated with C=O stretch and 1157 cm-1 correspond to the C-O stretch. These peaks were absence in its sodium salt spectrum. The thermogram of DFA measured by DTA is also displayed in Fig. 2, which shows the endotherm curve of melting at 173.8 °C, similar with the base-drug property (Barbato et al., 2003). Therefore,

Comparing by DFA, there was wave number shifting occurrence to the lower wave number from 1693 cm-1 (DFA) to 1681 cm-1 (DFA-PRO). The change of the wave number of carbonyl group, indicated the hydrogen bond formation between DFA and PRO. This prediction was also supported by shifting of OH free carboxylic acid of DFA from 3324 cm-1 to 3270 cm-1. The new broad spectrums at 1905 cm-1 and 2541 cm-1 were generated from hydrogen bond of O...H-N (heterocyclic) or O-H...N (heterocyclic). This phenomenon was similar with cocrystal formation of diclofenac acid with pyridines and pyrimidines families (Aakeröy et al, 2011). Based on our FT-IR spectrogram interpretation, there was strongly indicated that molecular interaction between DFA and L-Proline was a cocrystal

According to O’connor et al, 2001, the salt formation confirmed by the absence of the carbonyl peak at 1684 cm-1. In LAG of DFA-PRO, there was a peak of free carboxylic acid at 1683 cm-1. Aakeroy et al 2011, also stated that if original neutral diclofenac acid has been converted into a carboxylate moiety, COO-, will be appeared in IR spectrum below 1675 cm-1. Thus, this analysis was proved a cocrystal formation from DFA-PRO, not a salt formation. However, the determination of its exact structure, still be investigated recent with a single-crystal analysis. According to the design of cocrystal formation, once the cocrystal was arranged; only several functional groups are involved in the bonding. Therefore, the rests of them remaining were unaltered. By the analysis of FTIR spectrum of LAG product of DFA-PRO (1:1), a number of unique shifts of IR peaks as well as the new ones were shown at 3270, 3166, 1909 and 1681 cm-1.

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