primary hydroxyl groupsin butane-1,3-diol and butane-1,4-diol resulted in the formation of 3-hydroxy butanal and 4-hydroxy butanal, respectively.In the case of oxidation of the secondary hydroxyl groups in 2-methyl pentane-2,4-diol and 3-methyl pentane-2,4-diol, theproducts of oxidation were 4-hydroxy-4-methyl pentan-2-one and 4-hydroxy-3-methyl pentan-2-one, respectively.

CH3CH(OH)CH2CH2OH ---------------->CH3CH(OH)CH2CHO(ALDEHYDE)CH3(OH)CH2CH2CH2OH------------------->CH3(OH)CH2CH2CHO