H H acid HOOCCHCl2 Cl H O - C C Cl – – – O H (C) LABORATORY AND INDUSTRIAL PREPARATIONOF ALKANOIC ACIDS. In a school laboratory, alkanoic can be prepared by adding an oxidizing agent (H+/KMnO4 or H+/K2Cr2O7)to the corresponding alkanol then warming. The oxidation converts the alkanol first to an alkanal the alkanoic acid. NB Acidified KMnO4 is a stronger oxidizing agent than acidified K2Cr2O7 General equation: R- CH2 OH + [O] --H+/KMnO4--> R- CH + H2O(l) – –O (alkanol) (alkanal) R- CH + [O] R- C O – –OOH (alkanal) (alkanoic acid) Examples 1.Ethanol on warming in acidified KMnO4 is oxidized to ethanal then ethanoic acid . CH3- CH2 OH + [O] CH3- CH + H2O(l) – –O (ethanol) (ethanal) CH3- CH O + [O] --H+/KMnO4--> CH3- C – –OOH (ethanal) (ethanoic acid) 2Propanol on warming in acidified KMnO4 is oxidized to propanal then propanoic acid CH3- CH2 CH2 + [O] --H+/KMnO4--> CH3- CH2 CH + OH – –O H2O(l) (propanol) (propanal)
H H acid HOOCCHCl2 Cl H – O - C – C – Cl O H (C) LABORATORY AND INDUSTRIAL PREPARATIONOF ALKANOIC ACIDS. In a school laboratory, alkanoic can be prepared by adding an oxidizing agent (H+/KMnO4 or H+/K2Cr2O7)to the corresponding alkanol then warming. The oxidation converts the alkanol first to an alkanal the alkanoic acid. NB Acidified KMnO4 is a stronger oxidizing agent than acidified K2Cr2O7 General equation: R- CH2 – OH + [O] --H+/KMnO4--> R- CH –O + H2O(l) (alkanol) (alkanal) R- CH – O + [O] R- C –OOH (alkanal) (alkanoic acid) Examples 1.Ethanol on warming in acidified KMnO4 is oxidized to ethanal then ethanoic acid . CH3- CH2 – OH + [O] CH3- CH –O + H2O(l) (ethanol) (ethanal) CH3- CH – O + [O] --H+/KMnO4--> CH3- C –OOH (ethanal) (ethanoic acid) 2Propanol on warming in acidified KMnO4 is oxidized to propanal then propanoic acid CH3- CH2 CH2 – OH + [O] --H+/KMnO4--> CH3- CH2 CH –O + H2O(l) (propanol) (propanal)