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Unformatted text preview: Announcements Hand in crystallization report and benzoic acid product Print out revised report form from product. ( Print out revised report form from Blackboard. ) Find your ester assignment on Blackboard. The name of your ester is determined by your lab and bench number. Esters O R 1 O R 2 Organic compounds often associated with fragrances. Volatile esters are found in perfumes Volatile esters are found in perfumes, essential oils, and pheromones. They also give many fruits their They also give many fruits their scent. Esters Trimyristin triester glyceryl myristate Fragrant esters isopentyl acetate banana octyl acetate orange ethyl butyrate pineapple methyl butyrate apple isobutyl formate raspberry methyl salicylate wintergreen methyl salicylate wintergreen Esters R 2 O O R 1 R 1 OH HO R 2 O H 2 O + + H + Carboxylic Acid Alcohol Ester 2 1 2 The first half of an esters name corresponds to the parent alcohol and the other half derives from the name of the parent acid. + O O H 2 O + + H + OH HO O Ethanol Ethyl Ethanoate Ethanoic Acid (Ethyl Acetate) (Acetic Acid) Vinegar Vinegar Esters H O + O + H + O Isopropyl butanoate H 2 O + O Butanoic acid Isopropanol + OH HO HO OH + H + O H 2 O + Propyl isobutanoate Isobutanoic acid Propanol HO O O Propyl 2-methylproponate Acid Catalyzed formation of Esters OH R 1 OH O H + R 1 OH O H R 1 OH OH O R 1 OH O H R 2 + R 2 O H OH H + Shift H A R 1 OH O R O H H R 1 OR 2 O H- H 2 O R 1 OR 2 O- H + R 2 Esters Formation R 1 C O O R 2 R 1 C O OH O R 2 + H + H 2 O 1 2 1 2 H 2 O Reversible reaction --- slow Reversible reaction ---- slow.- Add catalyst (concentrated H 2 SO 4 ) The position of equilibrium can be controlled using The position of equilibrium can be controlled using Le Chatelieres principle. To shift the equilibrium to the right and increase the yield: Remove a product (water; ~1 mL con. H 2 SO 4 ) Add excess reactant (Large excess of acid) Quiz R 2 O R 1 O R 1 OH HO R 2 O H 2 O + + H 2 SO 4 If 2.0 mmol of carboxylic acid, and 1.0 mmol of alcohol are used, how many moles of water are produced?...
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- Fall '08
- Organic chemistry, Solvent, Carboxylic acid, Ester Parts