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Carboxylic acids and their derivatives

Carboxylic acids and their derivatives. Structure. Structure of derivatives. acyl halide. anhydride. acid halide. ester. amide. The acyl group. Nomenclature. HCO 2 H formic acid (from Latin formica , ant). CH 3 CO 2 H acetic acid (from Latin acetum , vinegar)

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Carboxylic acids and their derivatives

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  1. Carboxylic acids and their derivatives

  2. Structure

  3. Structure of derivatives acyl halide anhydride acid halide ester amide

  4. The acyl group

  5. Nomenclature HCO2H formic acid (from Latin formica, ant) CH3CO2H acetic acid (from Latin acetum, vinegar) CH3CH2CO2H propionic acid (from Greek protos, first and piôn, fat) CH3(CH2)2CO2H butyric acid (from Latin butyrum, butter) CH3(CH2)3CO2H valeric acid (valerian root) CH3(CH2)4CO2H caproic acid (from Latin caper, goat) CH3(CH2)6CO2H caprylic acid CH3(CH2)8CO2H capric acid

  6. Nomenclature -aminobutyric acid

  7. Nomenclature -hydroxypropionic acid or lactic acid isocaproic acid

  8. Aromatic acids p-bromobenzoic acid m-toluic acid

  9. Aldehydes - non-systematic names form(ic acid)aldehyde b-methylvaleraldehyde

  10. IUPAC CH3CH2CO2H propanoic acid (CH3)2CHCH2CH2CO2H 4-methylpentanoic acid 2-hydroxy-5-methyl-3-hexenoic acid (CH3)2CHCH=CHCH(OH)CO2H C-1

  11. Cyclic acids Saturated cyclic acids are named as cycloalkanecarboxylic acids: cis-2-methylcyclohexanecarboxylic acid

  12. Salts of carboxylic acids sodium benzoate (CH3CO2)2Ca calcium acetate or calcium ethanoate

  13. Nomenclature of derivatives

  14. Nomenclature of acyl halides Change -ic acid to -yl halide

  15. Nomenclature of anhydrides change acid to anhydride

  16. Nomenclature of amides change -icor -oic acid to -amide

  17. Nomenclature of esters change -ic acidto name of alcohol group or phenol + -ate

  18. Order of precedence of functional groups

  19. Physical properties Intermolecular hydrogen bonding is very important. In the solid and liquid states, carboxylic acids exist as dimers. Mp and bp values are far higher than the corresponding alcohols.

  20. Physical properties of acid derivatives Polar compounds: the acyl halides, anhydrides, and esters have boiling points which are very similar to those of aldehydes and ketones of equivalent molecular weight. However, the amides.......

  21. Dissociation of carboxylic acids ~ 10-5

  22. Relative acidities Relative basicities

  23. Acidity of carboxylic acids

  24. Structure of carboxylate ions

  25. Substituent effects CH3CO2H ClCH2CO2H Cl2CHCO2H Cl3CCO2H Ka 1.76x10-5 136x10-5 5530x10-5 23200x10-5 HCO2H CH3CO2H CH3CH2CH2CO2H Ka 17.7x10-5 1.76x10-5 1.52x10-5

  26. Salts of carboxylic acids • crystalline, non-volatile, decompose on heating to 300 - 400C. • sodium, potassium and ammonium salts are all water soluble and insoluble in non-polar solvents.

  27. Salts of carboxylic acids water insoluble water soluble NB: Phenols do not react with bicarbonate.

  28. Preparation of carboxylic acids

  29. Oxidation of primary alcohols

  30. Oxidation of arenes

  31. Oxidation of arenes

  32. The haloform reaction

  33. Carboxylation of Grignard reagents

  34. Carboxylation of Grignard reagents 2,2-dimethylpropanoic acid

  35. Hydrolysis of nitriles + NH3

  36. Preparation of nitriles - an SN2 reaction CH3CH2CH2CH2Br + CN- CH3CH2CH2CH2CN primary halide (CH3)3CBr + CN- (CH3)2C=CH2 + HCN

  37. Nomenclature of nitriles CH3CH2CN - 3 carbon chain propane + nitrile = propanenitrile propionic acid - ic acid + onitrile = propiononitrile ethanenitrile acetonitrile CH3CN pentanenitrile valeronitrile CH3(CH2)3CN

  38. The acyl group

  39. Reactivity of aldehydes and ketones

  40. Reactivity of carboxylic acid derivatives – nucleophilic addition - elimination G = -OH, -X, -OOCR, -NH2, or -OR Why?

  41. Reactivity of carboxylic acid derivatives The ease of loss of the leaving group, G, depends on its basicity: G = HO-, X-, RCO2-, NH2-, or RO- G = H-, R- ?

  42. Reactivity of carboxylic acid derivatives

  43. Base hydrolysis

  44. Acid hydrolysis

  45. SN2 v acyl substitution

  46. Nucleophilic displacement - reactivity

  47. Haloform reaction

  48. Haloform reaction

  49. acid chlorides Use thionyl chloride (SOCl2), phosphorus trichloride (PCl3) or phosphorus pentachloride (PCl5).

  50. acid chlorides

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