Question

what would be the percent yield if the final weight of my product is 0.1357g this is a green chemistry wittig reaction to produce 1,4-diphenyl-1,3-butadiene from benzyltriphenylphosphonium chloride and trans- cinnamaledyde using sodium hydroxide as the base

You will be using a Green Chemistry Wittig reaction (NOT Wittig-Horner Emmons reaction) to produce 1,4-diphenyl-1,3-butadiene starting with benzyltriphenylphosphonium chloride and trans- cinnamaledyde using sodium hydroxide as the base. This reaction is considered a "green" reaction, because an aqueous solution will be used for the reaction instead of N,N-dimethylformamide (DMF), methanol, or other solvents. For the workup you will be using ethanol instead of methylcyclohexane. The ylide (shown in figure 2 and 3) should react with trans-cinnamaldehyde to form 1,4-diphenyl-1,3- butadiene. Past experiments have shown that the trans, trans-isomer (E,E)-1,4-diphenyl-1,3-butadiene was the major isomer and the cis, trans-isomer (E,Z)-1,4-diphenyl-1,3-butadiene the minor isomer produced in this reaction. In the HPLC chromatogram of your product you will most likely see both. You can get more information about the Wittig reaction and the Wittig-Horner-Emmons reaction including their performance in the lab by reading Chapter 39 (pages 507 ff) of Williamson/Masters: Macro and Micro Experiments in Organic Chemistry, 6th edition other laboratory textbooks. Online resources might be helpful as well. FYI: The ylide in the reaction you will perform is shown in figure 2 and 3. The reaction mechanism for the (2+2) addition step is shown in figure 4. But in alteration to this mechanism, the ylide you will be using won't have 2 hydrogens attached to the ylide carbon. One hydrogen is replaced with a phenyl group. Don't forget to include the overall reaction as well. Procedure Place 2.10 mmol benzyltriphenylphosphonium chloride (Calculate BEFORE you come to the lab and know how many grams you need!) and 2.00 mmol trans-cinnamaldehyde (Calculate BEFORE you come to the lab and know how many ml you need. Use the molecular weight and the density for your calculation.) in a microscale Erlenmeyer flask. Add 1 mL water and stir the suspension with a stir bar and/or glass rod so that you have no clumps. Add 3 mL 10 N NaOH and stir the reaction mixture for 30 minutes with a stir bar. If it clumps, use a glass rod to remove the clumps. After the reaction time of 30 minutes, collect the crystals by micro vacuum filtration. Discard the filtrate (Waste container: reaction water). Wash the crystals in portions with water

Answer 1

trans cinnamaldehyde is present in (2.00 mmol) in less amount. -Hence it is limiting reagent. Theoretical yield = 2:00 mmol. reaction Thus, and is PhP + Phuto 2018 A Ph. I WAOH 4 Ph & Ph₂po Patah + ph i Mol. wt : Theoretical of product = 206 g molt yield a 2068 2 g o.noog rof Asha 1000 Observed yield = 0.1357 g :: 4. yield = (0:03:58, X100) 7.5 38.429. (Ares) 0.406