Synthesis of Triphenylmethanol Using the Grignard Reaction and Acid Workup Amanda Sokol Partner: Jack Platacz TA: Edgar Reyes Cruz Lab: Tuesday, 1:40 - 4:30 PM PSH 334 March 17, 2023 Abstract: The purpose of this experiment was to synthesize pure triphenylmethanol by preparing and performing the Grignard reaction followed by an acid workup step. The two-week process combined various techniques used in lab this semester thus far with some new techniques; the first week involved making the Grignard reagent and its reaction with Benzophenone, while the second week consisted of hydrolysis as well as extraction and purification of the product through recrystallization. The solid product was also characterized through melting point and infrared spectroscopy. Ultimately, the melting point range of pure triphenylmethanol was 162.1°C - 163.9°C. The experiment yielded 29.45% crude …show more content…
When the Grignard was prepared, magnesium was the limiting reactant and bromobenzene was in excess. Benzophenone was the limiting reactant in the Grignard reaction, and thus, benzophenone is used as the limiting reagent in the calculations below. After the experiment, the weight of the crude product was measured to be 0.460 g, and the weight of the pure product was 0.350 g. The molar mass of triphenylmethanol was found to be 260.3 g in the pre-lab. Thus, using the theoretical yield (Equation 3) and the weights of crude and pure product discovered, the percent yield of crude product (Equation 4), the percent yield of pure product (Equation 5), as well as the percent recovery (Equation 6) were determined. Moles of the Reactants: Moles of bromobenzene = weight of bromobenzene (g)molecular weight (g/mol) = 1.218 g157.01 g/mol = 0.0078 mol Moles of magnesium = weight of magnesium (g)molecular weight (g/mol) = 0.153 g24.3 g/mol = 0.0063