Carbolic Acid and Phenol have been considered similar for most organic chemistry engineers as medical doctors, pharmacists ...
In fact carbolic acid is a weak acid and phenol is a strong basis.
That means that carbolic acid and phenol like on the image are same in organic chemistry formula development, but they are completely different concerning endopeel in general chemistry and physico chemistry.
There are 3 main differences :
1-Resonance stabilization of the phenoxide anion by the aromatic ring.In this way, the negative charge on oxygen is shared by the ortho and para carbon atoms. That is why carbolic acid is used instead of phenol for endopeel techniques ( which lead to medical liftings obtained by chemical myoplasty, myopexy and myotension)
2-Increased acidity in the result of orbital overlap between the oxygen`s lone pairs and the aromatic system.
3-The dominant effect is the induction from the sp2 hybridized carbons;the comparatively more powerful inductive withdrawal of electron density that is provided by the sp2 system compared to an sp3 system allows the great stabilization of the oxyanion
1-Dewandre L., Tenenbaum A.. Chemical Peels of Drs. Mark G. Rubin and Rebecca Tung 2 nd Edition. Imprint: Saunders. Chapter 1: Chemistry of Peelings and Hypothesis of the Mechanism of Action ISBN: 978-1-4377-1924-6. Copyright: 2011