synthesis of aspirin equation, Schemes and Mind Maps of Chemistry

Download synthesis of aspirin equation and more Schemes and Mind Maps Chemistry in PDF only on Docsity! Synthesis of Aspirin equation Synthesis Purification Characterization Aspirin: some background ! Patented by Bayer in 1893 ! One of the oldest drugs ! One of the most consumed drugs (Production in the US is 10 million Kg/year) Organic background Alcohols ! Alcohols ! Aliphatic alcohols: Hydroxyl derivatives of saturated hydrocarbons ! Enols: Hydroxyl derivatives of unsaturated hydrocarbons R OH H3C OH methanol OH ethanol OH R R enol OH phenol Organic background Carboxylic acids O OHH O OH H.C O OH formic acid acetic acid benzoic acid R O OH Organic background Esterification R1 OH O HO R2 R1 O O R2 carboxylic acid alcool ester H+ + This is an equilibrium! Reaction OH OH O salicylic acid O O O acetic anhydride O OH HO O O acetyl salicylic acid (aspirin) OH O acetic acid H2SO4 heat + + Reaction mechanism OH HO O O O O O HO O O OH O H+ O HO O H+ OH O O + -H+ Safety ! Consult MSDS for safety information on all the chemicals you plan to use. ! MSDS are available from the 2507 webpage. Assessment of purity: Looking for properties Physical properties ! Physical appearance ! Solubility ! Melting point ! Infrared spectra Chemical properties ! Percent yield ! Potentiometric titration ! Phenol test Assessment of purity: Physical appearance ! Physical state (solid? liquid? ..) ! Color ! Odor ! Texture ! Homogeneity in composition Assessment of purity: Solubility ! In a test tube, transfer a small amount of your product (end of a spatula) ! Add ~1/2mL of solvent ! Determine solubility at room temperature ! If not, gently heat and determine solubility at higher temperature ! Test several organic solvents and compare with litterature Assessment of purity: Percent yield ! Definition: %Yield = nexp/nth ! Write down the reaction with the correct stoechiometry. Ex: A+B " C ! Prepare a chart like below and calculate yield. nC (mol) experimental mc (g) experimental nC (mol) theoretical mC (g) theoretical nB (mol) mB (g) or VB (mL) nA (mol) mA (g) or VA (mL) Assessment of purity: potentiometric titration ! Objective: Determine the pKa at the half equivalence point. ! Procedure: Titrate potentiometrically the acetylsalicylic acid with a strong base and find pKa O OH HO O O OHO O O O- Na+ + NaOH + H2O Assessment of purity: Phenol test and visible spectroscopy ! Phenol react with FeCl3 (aq) to give a deep purple complex. ! Phenol is not present in the product but in one of the reactant. ! This test indicate the presence of unreacted starting material (quantitative analysis possible via visible spectroscopy). OH OH O salicylic acid + Fe3+ Deep purple complex