Potassium phenolate

Potassium phenol-4-sulfonate (4-hydroxybenzene-l-sulfonic acid K salt) [30145-40-5] M 212.3. Crystd several times from distilled water at 90°, after treatment with charcoal, by cooling to ca 10°. Dried at 90-100°. 

The primary synthetic route proceeds via oxidative dimerization of 2-aminoan-thraquinone in the presence of an alkali hydroxide. 2-aminoanthraquinone, for instance, is fused with potassium hydroxide/sodium hydroxide at 220 to 225°C in the presence of sodium nitrate as an oxidant. New techniques involve air oxidation of 1-aminoanthraquinone at 210 to 220°C in a potassium phenolate/sodium acetate melt or in the presence of small amounts of dimethylsulfoxide. A certain amount of water which is formed during the reaction may be removed by distillation in order to improve both efficiency and yield. 

Reacts with sodium and potassium hydroxide forming sodium and potassium phenolate, respectively (Morrison and Boyd, 1971). 

The behavior of the same azoxybenzene is studied in homogeneous conditions— when the dipotassium salt of cyclooctatetraene dianion (CgHgKj) acts as a dissolved electrode. In this case, the reduction of azoxybenzene stops at the very first stage, that is, after the transfer of one electron only (Todres et al. 1975). The initial one-electron reduction produces the azoxybenzene anion-radicals, which are not reduced further despite the presence of residual electron donor in the solution. The ESR method does not reveal these anion-radicals although one-electron oxidation by phenoxyl radicals quantitatively regenerates azoxybenzene and produces the corresponding potassium phenolate molecules in a quantitative yield. Treatment with water leads to a 100% yield of azobenzene (Scheme 2.14). 

Challenge Phenol (C6H5OH) is a weak acid. Explain why a solution of the ionic compound potassium phenolate (C6H50 K ) is basic. 

The total number of drugs eluted from KOH-treated phases is less than the number eluted from similar phase nontreated coluims. The KOH treatment is done to reduce the adsorption of compounds by the support phase, and although it does this well, it also prevents the elution of phenolic base drugs such as morphine because of conversion to nonvolatile potassium phenolates. Many higher molecular weight alkaloids become thermolabile under such alkaline conditions and do not elute. Non-KOH treated phases have less tendency to cause such decomposition. 

It is an interesting fact that if potassium phenolate is used in the Kolbe synthesis para-hydroxy benzoic acid is obtained, especially at high temperatures. Potassium phenyl carbonate is first formed, and heated up to 150° yields salicylic acid, but if the temperature be further raised, the para-acidis produced in increasing quantities until at 220° potassium para-hydroxy-benzoic acid is the sole product. 

A variation of this method consists in heating carbon tetrachloride with potassium phenolate under pressure with sufficient alcohol to give a clear solution. The product in this case is mostly the orfAo-acid (cf. Reaction XXXIV. (q)),... 

On subjecting a neutral potassium phenolate solution to the action of the electric current they were able to isolate a compound, C65H48O22, soluble in alkali and precipitated from such s solutions by mineral acids. This latter compound on being oxidized with nitric acid formed picric acid. When allowed to remain in solution in the presence of dilute acids for a pro-... 

Anisole has been prepared by a variety of other methods, the most important being from sodium or potassium phenolate and methyl iodide 1 from sodium phenolate and methyl chloride 2... 

The effect of both podands and coronands on the Sn2 alkylation of potassium phenolate with 1-bromobutane in 1,4-dioxane s = 2.2) has been investigated by Ugel-... 

The reaction of a n-butylboronic precursor with potassium phenolate led to the formation of hexaphenol Fe((C6H50)2Gm)3(Bre-C4H9)2 complex (Scheme 13). Attempts to obtain of the n- and t-butoxy-containing clathrochelates met with failure because of the destruction of precursors. 

Sodium phenolate, CjHsONa. Magnesium methyl carbonate (which see) has been shown to be an effective agent for carboxylating active methylene groups. Italian investigators have found that sodium (or potassium) phenolate in combination with carbon dioxide carboxylates cyclohexanone in dimethylformamide to give... 

If in the Kolbe reaction instead of sodium phenolate, potassium phenolate is used, the para-oxybenzoic add is obtained, and not the ortho-add. The potassium phenolate, like the sodium phenolate, first absorbs carbon dioxide, and the potassium phenyl carbonate thus formed, heated in carbon dioxide up to 150°, also yields salicylic add but if the temperature is increased, an increasingly larger quantity of the para-add is obtained, until finally at 2200 the potassium para-oxybenzoate is the only product. 

Kolbe-Schmidt reaction. The preparation of salicyclic acid or its derivatives from carbon dioxide and sodium or potassium phenolate. 

Phenol readily couples with diazonium salts to yield coloured compounds. The latter can be nsed for the photometric detection of phenol as in the case of diazotized 4-nitroaniline. Sahcylic acid (2-hydroxybenzoic acid) can be prodnced by the Kolbe-Schmitt reaction (stndied by the density functional method ) from sodinm phenolate and carbon dioxide, whereas potassium phenolate gives the para compound. Alkylation and acylation of phenol can be carried out with aluminium chloride as catalyst methyl groups can also be introduced by the Mannich reaction. Diaryl ethers can only be produced under extreme conditions. 

Phenol reacts with hnear and branched alkenes in the presence of trill uoromethane-sulfonic acid (CF3SO3H) in chloroform to give the ortho- and para-aUcylphenols, in moderate yields (equation 8) °. With branched alkenes, the para-alkyl phenols are the major products. The regioselectivity is dramatically altered from entirely para-alkylphenol to ortlio-alkylphenol going from 100% potassium phenolate to 0% potassium phenolate in the presence of the Lewis acid AICI3. 

The behaviour of the most sterically hindered 2,6-di-rerr-butylphenol (25) and its derivatives was very dependent upon the reaction conditions. In the presence of a base favouring electron-transfer (such as BTMG), oxidation reactions took place with triphenylbismuth dichloride or triphenylbismuth carbonate leading to the diphenoquinone (26). Para-phenylation with formation of (27) was observed for the first time in the reaction of the potassium phenolate of 2,6-di-re rr-butylphenol with triphenylbismuth dichloride and in the reaction of the phenol (25) with tetraphenylbismuthonium tosylate in the presence of BTMG. Even ortho- and para-phenylation with concomitant de-rerr-butylation occurred in the reaction of the potassium salt of 2,4,6-tri-re r/-butylphenol with triphenylbismuth dichloride. 2... 

Aryl monothiolcarbonates have been obtained in 60% yield from a potassium phenolate in dioxan/dimethyl sulphoxide and carbon oxysulphide during 3 hours at ambient temperature foliowed by alkylation with a primary halide (PrI) as shown (ref.23). 

In another reaction of a different type, probably involving anionic nucleophilic attack, potassium phenolate was treated first in toluene solution with stannic chloride in the same solvent at ambient temperature followed by refluxing for 15mins. Finally to the mixture at 80°C over 3 hours a toluene solution of diethyl 2-vinylcylopropane-1,1-dicarboxylate was introduced and reaction continued over a further 10 hours, to give ethyl 6-(2-hydroxyphenyl)-2-ethoxycarbonyl-4-hexenoate in 25% yield (85% based on recovered phenol) (ref.38). 

Aryl alky ethers. The reaction of an alcohol with hexamethylphosphorous triamide in carbon tetrachloride at low temperatures results in formation of an alkoxytris(dimethylamino)phosphonium chloride (1), which can be converted into the stable hexafluorophosphate (2) by addition of ammonium hexafluoro-phosphate. The salt (2) reacts with potassium phenolates or aryl thiophenolates... 

Protonation of a polyhydride can occur at the metal, increasing the number of hydride ligands or leading to a rj -Uz ligand, which can liberate as H2. In spite of the low kinetic and thermodynamic (pXa = 25.5 in acetonitrile) acidity of [ReH4(PMe2Ph)4] +, deprotonation occurs by abase like potassium phenolate. Replacement of one phosphine by CO enhances the acidity of the complex by at least 7 orders of magnitude (pXg < 18.5). ... 

It has been found [117] that polyethylene glycol (PEG) produces a strong catalytic effect during the reaction of butyl bromide with KI. The yield of the butyl iodide product increases linearly with an increase in the length of the PEG chains. A similar acceleration of the reaction between solid potassium phenolate and 1-bromobutane is observed in toluene in the presence of oligoethylene glycols [178]. The synthesis of 8 esters based on alcohols and phenols in two-phase system liquid-liquid catalyzed by PEG is discussed [178a]. 

Furthermore, the hydrolysis of butyl acetate and methyl pivalate in benzene in the presence of KOH at 25 °C as well as the reaction of potassium phenolate with benzyl chloride in boiling acetonitrile are accelerated by addition of polyoxyethylene [183]. The catalytic effect of POE is augmented by an increase in the number of oxyethylene units, i.e. 1 <6< 12. PEO is also an interfacial catalyst of the reaction of phenol and 2,4,6-trimethylphenol with methyl iodide in water-chloroform and dichloromethane. The kinetic study of the reaction between benzyl chloride and potassium acetate in the presence of PEO of variable molecular weight in toluene and butanol has been performed with IR spectroscopy [184]. The dissolution of a reagent of poor solubility is apparently a rate-limiting step of the reaction in a solution of low polarity (toluene). The presence of PEO impurities in toluene has been detected. Moreover, effect of PEO and crown ethers as phase transfer catalysts has been compared. In a low-polarity solvent, oligoethylene oxides are more effective catalysts, while in a polar solvent (butanol) the effectiveness of PEO and crown ethers as phase transfer catalysts is similar. 

The monoadduct of tetraene 11 and benzoquinone [107] can be reduced selectively into alcohol 37 (94%), the structure of which has been established by X-ray radiocrystaUography [163]. The corresponding mesylate 38 eliminates one equivalent of methanesulfonic acid in the presence of two equivalents of f-BuOH/THF giving a potassium phenolate 39 that is reacted with Mel to give the corresponding anisole 40 (99%). When an excess of base is used (4.3 equivalents of f-BuOK), the phenolate intermediate 39 is isomerized re-gioselectively (7 3) into the vinylphenolate 41. 

---