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The acidity of the hydroxyl group in phenols is commonly intermediate between that of aliphatic alcohols and carboxylic acids (their pK a is usually between 10 and 12). Deprotonation of a phenol forms a corresponding negative phenolate ion or phenoxide ion , and the corresponding salts are called phenolates or phenoxides ( aryloxides according ...
Phenol (also known as carbolic acid, phenolic acid, or benzenol) is an aromatic organic compound with the molecular formula C 6 H 5 OH. [5] It is a white crystalline solid that is volatile. The molecule consists of a phenyl group (−C 6 H 5) bonded to a hydroxy group (−OH). Mildly acidic, it requires careful handling because it can cause ...
Sulfonic acids, containing the group –SO 2 OH, are relatively stronger acids. Alcohols, with –OH, can act as acids but they are usually very weak. The relative stability of the conjugate base of the acid determines its acidity. Other groups can also confer acidity, usually weakly: the thiol group –SH, the enol group, and the phenol group ...
The higher the proton affinity, the stronger the base and the weaker the conjugate acid in the gas phase.The (reportedly) strongest known base is the ortho-diethynylbenzene dianion (E pa = 1843 kJ/mol), [3] followed by the methanide anion (E pa = 1743 kJ/mol) and the hydride ion (E pa = 1675 kJ/mol), [4] making methane the weakest proton acid [5] in the gas phase, followed by dihydrogen.
Phenol: 181.75 3.60 43.0 –7.27 K f [2] K b [1] Water: 100.00 0.512 0.00 –1.86 K b & K f [2] Ethyl Acetate: 77.1 [5] Acetic Anhydride: 139.0 [6] Ethylene Dichloride: 1.25 83.5 −35 [7] Acetonitrile: 0.78 81.6 −45 [8] Heptane: 98.4 [9] Isobutanol: 107.7 [10] n-Hexane: 0.66 68.7 [11] n-Butanol: 117.7 [12] Hydrochloric Acid: 84.8 [13] tert ...
The acidity of alcohols is strongly affected by solvation. In the gas phase, alcohols are more acidic than in water. [35] In DMSO, alcohols (and water) have a pK a of around 29–32. As a consequence, alkoxides (and hydroxide) are powerful bases and nucleophiles (e.g., for the Williamson ether synthesis) in this solvent.
Acid strength is the tendency of an acid, symbolised by the chemical formula, to dissociate into a proton, +, and an anion, . The dissociation or ionization of a strong acid in solution is effectively complete, except in its most concentrated solutions.
It is often said the resonance stability of phenol makes it a stronger acid than that of aliphatic alcohols such as ethanol (pK a = 10 vs. 16–18). However, a significant contribution is the greater electronegativity of the sp 2 alpha carbon in phenol compared to the sp 3 alpha carbon in aliphatic alcohols. [7]