Complete the following acid-base reactions and predict the direction of equilibrium (to the right or to the left) for each. Justify your prediction by citing values of pKa for the stronger and weaker acid in each equilibrium. For values of acid ionization constants, consult Table 23.2 (Acid Strengths, pKa, of the Conjugate Acids of Selected Amines) and Appendix 2 (Acid Ionization Constants for the Major Classes of Organic Acids). Where no ionization constants are given, make the best estimate from the information given in the reference tables and sections. PhC=CH+NH3 =PhenylacetyleneAmmonia Table 23.2 Acid Strengths, pK, of the Conjugate Acids of Selected AminesAmineStructurepk, of Conjugate AcldAmmoniaNH,9.26Primary AminesMethylamineCH,NH,10.64EthylamineCH,CH,NH,10.81CyclohexylamineCH,NH,10.66Secondary AminesDimethylamlne(CH),NH10.73Diethylamine(CH,CH,),NH10.98Tertiary AminesTrimethylamine(CH,),N9.81Triethylamine(CH,CH,),N10.75Aromatic AminesAniline-NH,4.634-MethylanilineCH,-NH25.084-ChloroanlineCI-NH24.154-NitroanllineO,N--NH,1.0Aromatic Heterocyclic AminesPyridine5.25Imidazole6.95

The reaction of an acid with the base results in the formation of a salt. In an equilibrium…

PhC=CH + NH3 = Phenylacetylene Ammonia Table 23.2 Acid Strengths, pK, of the Conjugate Acids of Selected Amines Amine Structure pk, of Conjugate Acld Ammonia NH, 9.26 Primary Amines Methylamine CH,NH, 10.64 Ethylamine CH,CH,NH, 10.81 Cyclohexylamine CH,NH, 10.66 Secondary Amines Dimethylamlne (CH),NH 10.73 Diethylamine (CH,CH,),NH 10.98 Tertiary Amines Trimethylamine (CH,),N 9.81 Triethylamine (CH,CH,),N 10.75 Aromatic Amines Aniline -NH, 4.63 4-Methylaniline CH, -NH2 5.08 4-Chloroanline CI- NH2 4.15 4-Nitroanlline O,N- -NH, 1.0 Aromatic Heterocyclic Amines Pyridine 5.25 Imidazole 6.95

PhC=CH + NH3 = Phenylacetylene Ammonia Table 23.2 Acid Strengths, pK, of the Conjugate Acids of Selected Amines Amine Structure pk, of Conjugate Acld Ammonia NH, 9.26 Primary Amines Methylamine CH,NH, 10.64 Ethylamine CH,CH,NH, 10.81 Cyclohexylamine CH,NH, 10.66 Secondary Amines Dimethylamlne (CH),NH 10.73 Diethylamine (CH,CH,),NH 10.98 Tertiary Amines Trimethylamine (CH,),N 9.81 Triethylamine (CH,CH,),N 10.75 Aromatic Amines Aniline -NH, 4.63 4-Methylaniline CH, -NH2 5.08 4-Chloroanline CI- NH2 4.15 4-Nitroanlline O,N- -NH, 1.0 Aromatic Heterocyclic Amines Pyridine 5.25 Imidazole 6.95

Organic Chemistry

9th Edition

ISBN:9781305080485

Author:John E. McMurry

Publisher:John E. McMurry

Chapter22: Carbonyl Alpha-substitution Reactions

Section22.1: Keto–enol Tautomerism

Problem 1P

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