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Preparing Azo Dyes Using Combinatorial Methods For The Formation Of An Azo Dye

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The purpose of this experiment was to prepare azo dyes using the combinatorial approach to show the principles combinatorial chemistry. Using combinatorial synthesis, an array of chemicals can be synthesized by using a parallel synthesis to identify potentially valuable compounds. This electrophilic aromatic substitution reaction involved multiple steps to complete, however, no major techniques were used; only the use of a hot place and an ice bath. The specific azo dyes produced in this experiment used the coupling partners 1-naphthol and 2-naphthol with 3-aminobenzenesulfonic acid. The azo dye for the meta reaction of 1-naphthol with 3-aminobenzenesulfonic acid yielded a very dark red color. The azo dye for the meta reaction of …show more content…

Less energy is required to raise the energy levels of aromatic azo compounds with less conjugation and therefor, less high energy waves are absorbed and the dye appears increasingly blue/black.
Figure 1: Conjugation levels of various common aromatic azo compounds. As a class, we were able to compare and contrast the colors of the aromatic azo compounds from several different coupling partners as well as different substitution patterns for each (i.e. ortho, para, meta). This type of synthesizing molecules to create an array of potentially useful compounds is known as combinational chemistry. In combinatorial synthesis, when using a compound with multiple points of diversity, or R groups which can be substituted, a substantial number of possible structures can be found depending on the number of substituents utilized. Laboratories can use automated technologies to perform these types of reactions on an industrial scale but scientists can also utilize these methods to synthesize and compare a select few molecules [2]. More specifically, the type of combinatorial synthesis utilized by our lab is known as “parallel synthesis”. In parallel synthesis, a number of reactants are available to react individually with a number of substrates which produces a substantial number of unique and potentially useful compounds. One way of organizing the information about these reactions is to create a table with the reactants

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