Various ethers are used for hydroxyl protection. My question is about their removal. I know that there are various methods but I want to specify on the use of acids.
Certain groups are removed easily like Trityl, by using aqueous acetic acid. If I'm not mistaken, the mechanism is Sn1, as the trityl carbocation is stabilised through delocalisation on the phenyl groups.
However, other similar groups like benzene or PMB are not removed that easily. Can't they follow the same logic, as the postive charge could again be delocalised in the aromatic ring? Is it because the delocalisation is not good enough, as in the case of trityl?
Also, I've noticed that in order to remove smaller groups like methyl, haloacids are mainly used. Why can't a more weak acid do the job?