Grignard Reaction Essay

1647 Words7 Pages
The Grignard Reaction Synthesis of triphenylmethanol Josh Wilson Chem 443-003 January 1,2012-February 7,2012 Introduction In this experiment we synthesized triphenylmethanol from a Grignard reagent and an ester. To form triphenylmethanol we reacted methyl benzoate with phenylmagnesium bromide. Reaction Scheme: Theory An organometallic compound is an organic compound that contains a Carbon-metallic bond. The metal can be Li, Na, Mg, Cu, Pd or any other transitional metal. In this lab we used Mg as our metallic portion of the organometallic compound. Organometallic compounds are special in that they cause Carbon to become a nucleophile. More specifically in this lab we used R-Mg-Br an alkyl magnesium halide to project the nucleophillic properties onto the Carbon atom, known as a Grignard reagent because of it founder chemist Victor Grignard. The purpose of Grignard reactions is to create a C-C bond, more specifically a tertiary or a secondary alcohol. The Grignard reagents are usually created with the solvents anhydrous diethyl ether or THF and are very air sensitive. The Grignard reagent are very basic which make them very good proton acceptors. In our experiment we created a tertiary alcohol by using an ester and carbonyl molecule. The ester is converted to a ketone than immediately reacts with the Grignard reagent to give the tertiary alcohol, triphenylmethanol. Reaction Mechanism Procedure A. Preparation of the Grignard reagent * Weigh about .5 g of Magnesium turnings * Use mortar and pastel to grind turnings * Put tunings into round bottom flask * Assemble apparatus * Prepare 2.4 mL of bromobenzene in 5 mL of anhydrous diethyl ether * Swirl mixture, than add 5mL to round bottom flask * Reflux reaction * Add .5 mL increments of the ethereal solution over 10 minutes B. Synthesis of
Open Document