P-Cyanophenols

MILLER - SNYDER Aiyl Cyanide Synthesis Synthesis of benzonitnies from aldehydes via oxime ethers Formation of p-cyanophenol from p nrtrobenzaldoxime and p-nitiobenzonitnle (used as a sometimes recyclable chain carrier)... 

The reaction of p-cyanophenol with o-dinitrobenzene in the presence of KF in DMSO gives the corresponding diaryl ether in 95% yield (Eq. 9.4).7... 

FIGURE 6 Effect of p-cyanophenol on the separation of perchlorate. Column 4x250mm lonPac ASII. Flow rate I.OmLmin. Injection volume 25pL. Detection suppressed conductivity utilizing the Anion Self Regenerating Suppressor (4mm), recycle mode. Ion I—perchlorate (20mgL" ). (a) Eluent lOOmM NaOH. (b) Eluent 50 mM NaOH and 5mM p-cyanophenol. 

Compound from p-Cyanophenol.—p-Cyanophenol and the base in absolute alcohol give 2(C6H5)5Cr.O.C6H4.CN.HO.C6H4.CN, crystallising in columns, M.pt. 123-5° C. This body readily dissolves in alcohol, acetone, pyridine or chloroform, but is insoluble in benzene or ether. 

Two different approaches have been used to determine phenols without derivatization. In the first, the corresponding oxalate esters were synthesized in the traditional way (i.e., using oxalyl chloride and triethylamine) [111, 112]. Pen-tachlorophenol, 1 naphthol, bromofenoxim, bromoxynil, and p cyanophenol were treated this way, after which the POCL resulting from their reaction was measured in a static system. The second approach exploits the oxidation reaction between imidazole and hydroxyl compounds at an alkaline pH, where hydrogen peroxide is formed [113]. Polyphenols, e.g., pyrogallol, pyrocatechol, and dopa-... 

Removal rates greater than 90% were observed for all of the phenols studied. The decay kinetics for phenol p-methoxyphenol p-cresol p-fluo-rophenol p-chlorophenol p-bromophenol 4-hydroxyacetophenone a,a,a-trifluoro-p-cresol p-cyanophenol and p-iodophenol were found to be consistent with the Langmuir-Hinshelwood kinetic model. After employing all the substituents, little variation on the Langmuir-Hinshelwood kinetic parameters was observed. 

The p-cyanophenol derivative 57 was selectively transformed into the linear tricyclic cyclobutene derivative 58 (Scheme 5.11, reaction 24) [57]. The hydroxyace-tophenone derivative 59, carrying two additional methyl groups at the benzene ring, yields selectively the angular tricyclic cyclobutene derivative 60 (reaction 25) [58]. It should be stressed here that the back-reaction to the corresponding cyclooctatriene compound is inhibited by the methyl substituent at the cyclobutene moiety of 60. Chiral induction was performed with derivatives carrying a chiral ester or amide function on the hydroxyacetophenone ring [59]. 

Solution We saw in Section 16.6 that a cyano group is electron-withdrawing. Thus, p-cyanophenol is more acidic tp/C, 7.97) than phenol (pff 9.891. 

PiKtke Problem 17.1 Is p-cyanophenol more acidic or less acidic than phenol ... 

Fig. 3-1. Representation of the sorption effects in the separation of bromide and nitrate. - Separator IonPac AS4 eluent 0.0043 mol/L NaHC03 + 0.0034 mol/L Na2C03 + 100 mg/L p-cyanophenol flow rate 2 mL/min detection suppressed conductivity injection volume 50 pL solute concentrations 3 ppm fluoride, 4 ppm chloride, 10 ppm nitrite, 10 ppm phosphate, 10 ppm bromide, 20 ppm nitrate, and 25 ppm sulfate.

Fig. 3-18. Effect of p-cyanophenol on the tailing properties of iodide and thiocyanate. - Chromatographic conditions see Fig. 3-1.

The aromatic amino acid tyrosine has proved successful as an eluent for the simultaneous analysis of all halide anions, which also causes a reduction in the iodide retention at alkaline pH, while still allowing for the separation of bromide and nitrate in contrast to p-cyanophenol containing eluents. In the respective chromatogram obtained with tyrosine as the eluent, a reversed retention is observed for orthophosphate and sulfate. This is caused by the comparatively high pH value of the mobile phase. The... 

The introduction of the IonPac AS5 separator column significantly facilitated the analysis of polarizable anions. Reducing the hydrophobicity of the functional groups bonded to the latex beads makes it possible to elute polarizable anions using a standard mixture of sodium bicarbonate and sodium carbonate. To minimize adsorption phenomena, some p-cyanophenol is added to the eluent mixture. The influence of this species on the peak form is evident in Fig. 3-18. The peak broadening could also be greatly reduced because of the compatibility of the eluent with commercial membrane suppressors and the reduction in the void volume. 

Salts of other weak acids may also be employed as the eluent. For example, extensive investigations were performed with p-cyanophenolate ions [130] which, compared to hydroxide ions, exhibit a slightly stronger elution power. A high selectivity for aliphatic dicarboxylic acids is obtained with p-cyanophenolate in combination with a CarboPac PA-1 (IonPac AS6) anion exchanger. Nevertheless, this eluent has not gained acceptance because it is not commercially available in the required purity. 

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