Why can't tertiary alcohols be oxidized?
Simple answer ... you need at least one hydrogen attached to
carbinol carbon. in other words, you have a hydrogen on the oxygen
to give you the hydroxyl group that is attached to the carbinol
carbon, but you also need a hydrogen coming off that carbon. The
reason - your reagent, such as chromic acid, joins with the alcohol
at the position of the hydroxyl group, which leads to an H2O
molecule being shot off. The chromic acid provides the -OH of that
water, but takes the H off the hydroxyl group to get the 2nd
hydrogen atom. You would now have a chromate ester + water. The
water then takes off a hydrogen atom attached to the carbinol
carbon, which leaves the electrons to form a double bond with the
Oxygen atom. Without the hydrogen attached to the carbinol carbon
... like in a tertiary alcohol ... oxidation could only take place
by breaking carbon-carbon bonds, which requires severe conditions.
Even if this did happen, you would get a mixture of products.