Essay Wittig reaction

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SYNTHESIS OF TRANS-9-(2-PHENYLETHENYL) ANTHRACENE (A WITTIG REACTION) Introduction: The purpose of this experiment is to convert carbonyl compounds to alkenes using Wittig reaction. In this case we will be synthesizing Trans-9-(2-phenylethenyl) anthracene from benzyltriphenylphosphonium chloride and 9-anthraldehyde. We will also aim to obtaining a high percent yield and purity for the synthesis of Trans-9-(2-phenylethenyl) anthracene. The mechanism for this reaction goes thus: Experimental: Benzyltriphenylphosphonium chloride (0.201g) and 9-anthraldehyde (0.116g) were weighed and added to a short-neck round-bottomed flask (5ml). Dichloromethane (2ml) was measured using a measuring cylinder and added to the…show more content…
Hickey) Organic chemistry lab 2 manual, department of Chemistry University of New Orleans. We observed a yellow residue in the bottom of the flask after the dichloromethane has been boiled off, and 2-propanol (3ml) was added to it and then was heated until the entire residue dissolved and the solution was transferred to a clean Erlenmeyer flask. After allowing the flask to cool to room temperature and cooling on ice, the product was collected and washed with 2-propanol (2ml) into a clean Hirsch funnel and was filtered using vacuum filtration. The triphenylphosphine oxide remained in the propanol solution, and the crystals were dried by drawing air through them. The mass, percentage yield and melting point of the product was obtained. The crystals were stored in a glass vial for next experiment. Data/calculations Mass of product obtained = 0.077g Mole Ratio for both C25H22PCl and C15H10 O with product is 1:1 Determination of the number of moles for each reactant: Benzyltriphenylphosphonium chloride (C25H22PCl) = 9-anthraldehyde (C15H10 O) = The limiting reagent is therefore Benzyl triphenylphosphonium chloride. The theoretical yield of 9-(2 phenylethenyl) anthracene is 0.145g Actual 0.077g Percentage yield = Melting Point: Fast ramp Slow ramp Start temp.
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