Polarity
Oxydising a non polar carbon chain is very difficult (not talking about combustion, with Oxygen).
The division of valency electrons is in those chains very equilibrated and equal; there is no difference in electronegativity.
The presence of charges δ+ and δ- can cause nucleophylic and electrophylic attacks with redoxreactions as a consequence.
As soon as there is an Oxygen atom connected to the chain, there is polarity that makes redox reactions (transfer of electrons) more easy to occur.
The Oxygen atom, or any other atom with a good electronegativity, causes the needed polarity in that substance.
But note: not only polarity is needed; there must also be a position where more Oxygen atoms (or other electronegative atoms) can be connected.
A general rule is:
a C-atom in a carbon chain can be oxydised when that C simultaneously:
has an O ánd an H
an extra O can be connected between the C and that H.
In other words: To oxydise a carbonchain, there must be already an O-atom at the C-atom to oxydise, and also, that same C-atom must have at least one H-atom.
Normally, during the oxydation, an O is connected between the C and the H:
H becomes then: OH / In fact an H is substituted by an OH.
Mind:
Ether molecules have an O-atom between two C-atoms. There is a certain symmetria, so less polarity; in this case oxydation becomes more difficult.
A bonding between two carbon atoms is - in normal oxydation reactions - difficult to break; carbon chains normally remain unchanged (execpt in the case of direct combustion with Oxygen, where carbondioxyde and water are made).