Two Step Synthesis of a Novel Phthalein Based pH Indicator

Faculty Mentor(s) Name(s)

Wathsala Medawala

Abstract

Conventional phthalein dyes are used as pH indicators due to their distinct color change in solutions of different pHs. For example, a solution of phenolphthalein in water turns from colorless to pink as the pH of the solution is increased from acidic to basic. Here, we propose a two-step synthesis of a novel phthalein based pH indicator from commercially available materials that utilizes reactions commonly encountered in undergraduate organic chemistry courses. In step one, the pure product of 1-phenyl-2,3-naphthalenedicarboxylic anhydride was obtained which was used in step two by reacting it with phenol. The final product obtained contained acid base color change indicator properties similar to phenolphthalein. Currently, we are attempting to purify the final indicator product to better characterize it through NMR and melting point analysis. Once the pure indicator product is obtained, the synthesis will be incorporated into the organic chemistry and quantitative analysis laboratory curriculum at Georgia College with the aim of enhancing student learning outcomes through a student-centered hands-on pedagogy.

Start Date

27-3-2024 10:00 AM

End Date

27-3-2024 10:50 AM

Location

Magnolia Ballroom

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Mar 27th, 10:00 AM Mar 27th, 10:50 AM

Two Step Synthesis of a Novel Phthalein Based pH Indicator

Magnolia Ballroom

Conventional phthalein dyes are used as pH indicators due to their distinct color change in solutions of different pHs. For example, a solution of phenolphthalein in water turns from colorless to pink as the pH of the solution is increased from acidic to basic. Here, we propose a two-step synthesis of a novel phthalein based pH indicator from commercially available materials that utilizes reactions commonly encountered in undergraduate organic chemistry courses. In step one, the pure product of 1-phenyl-2,3-naphthalenedicarboxylic anhydride was obtained which was used in step two by reacting it with phenol. The final product obtained contained acid base color change indicator properties similar to phenolphthalein. Currently, we are attempting to purify the final indicator product to better characterize it through NMR and melting point analysis. Once the pure indicator product is obtained, the synthesis will be incorporated into the organic chemistry and quantitative analysis laboratory curriculum at Georgia College with the aim of enhancing student learning outcomes through a student-centered hands-on pedagogy.