CarboxylicAcidandderivative（化学课件）地道英语教学.ppt

* * Organic Chemistry Carboxylic acids 02 Introduction General formula: CnH2n+1COOH Contains the carboxyl (–COOH) functional group Carboxyl group Stem 02 Introduction A weak organic acid Dissociates partially in water to give H+ ions Acidic proton = Only this will dissociate to give H+ ions Ethanoic acid CH3COOH Methanoic acid HCOOH Structural Formula Name Molecular Formula Nomenclature of Carboxylic Acids CH3COOH HCOOH C3H7COOH Butanoic acid Propanoic acid C2H5COOH Structural Formula Name Molecular Formula Nomenclature of Alkenes CH3CH2CH2COOH CH3CH2COOH Structural Isomerism Can carboxylic acids exhibit isomerism? Physical Properties Very soluble 168 Liquid Butanoic acid Very soluble 141 Liquid Propanoic acid Very soluble 118 Liquid Ethanoic acid Very soluble 101 Liquid Methanoic acid Solubility in water Boiling Point (oC) Physical State Alcohol B.P. and M.P. increases as no. of carbon atoms increases. Physical Properties Very soluble 168 Liquid Butanoic acid Very soluble 141 Liquid Propanoic acid Very soluble 118 Liquid Ethanoic acid Very soluble 101 Liquid Methanoic acid Solubility in water Boiling Point (oC) Physical State Alcohol Carboxylic acids are very soluble in water. Production of Carboxylic Acids Carboxylic acids can be obtained by: Oxidation of alcohols Oxidation (to form carboxylic acids) Alcohols can be easily oxidised by air or common oxidising agents to form its corresponding alcohols. Alcohol KMnO4 or K2Cr2O7 Heat under reflux CnH2n+1OH CnH2n+1COOH H2O + + 2 [O] Carboxylic acid acidified Production of Carboxylic Acids Reaction of Carboxylic Acids A carboxylic acid will dissociate partially in water to give hydrogen (H+) ions and carboxylate ions (RCOO-). Ethanoic acid Ethanoate ion hydrogen ion Reaction of Carboxylic Acids Like all acids, the hydrogen ion gives the carboxylic acid its chemical properties. Hence, when dissolved in water, carboxylic acid will turn blue litmus red. Carboxylic acids will also participate in reactions similar to an