Conversion to phenols

An important reaction of aryl diazonium ions is their conversion to phenols by hydrolysis... 

CD-Cumene A process for making cumene for subsequent conversion to phenol and acetone. The cumene is made by catalytic alkylation of benzene with propylene in a catalytic distillation reactor. Developed in 1995 by CDTech. 

Conversion to phenolates coupled with NMR analysis has been used in determining the relative locations of the hydroxyl and methoxyl groups in phenolic pavines (1,25). Moreover, changes in chemical shifts of neighboring aromatic protons when going from a CDCI3 solution to a DMSO solution had been useful in assigning the correct position of the phenol (25,112). 

The metabolism of thiophene (100) was first studied in 1886 by Heffter (1886MI10900), who administered it orally to dogs and noted the increased output of ethereal sulfates in urine. This is typical of aromatic hydrocarbons conversion to phenolic products which are excreted in urine as sulfate conjugates. When fed to rabbits, there was no increase in the ethereal sulfate output, but there was some indirect evidence of the presence in urine of dihydrodiols and thienylmercapturic acids (45MI10900). This was confirmed by Bray and coworkers (71MI10906,68BJ(109)11P>, who studied thiophene and benzothiophene metabolism in rabbits and rats. The only identifiable metabolites in urine were the thienylmercapturic acids (101) and (102), which are probably formed via conjugation of the intermediate... 

The thermal decompn of Cumene Hydroperoxide has been studied by several authors (cited in Refs 6 8). Realization of the potential industrial importance of this compd and its acid-catalyzed conversion to phenol acetone, caused the appearance of many papers many patents involving the efficiency of both the oxidation process and the decompn stage (Ref 3)... 

Complexes (160) (see equation 35) undergo conversion to phenols upon thermolysis. Alternatively, treatment with AICI3 under a CO atmosphere gives an j)" -iron cyclohexadienone complex thermolysis or treatment with CuCl2 affords a phenol as well. Complexes (162), derived from nucleophihc addition to ( ) -pentadienyl)Fe(CO)3+ cations (see equation 37), can be converted to vinyl cyclopropanes by using CAN (equation 41). ... 

Catalyst S102/A1203 Selectivity of benzene conversion to phenol, % Productivity, mmole phenol per gram of catalvst per hour Ref. 

The successful commercialization of the overall process concept depended on the viability of the first step which is a breakthrou technology. The data reported in the literature showed high selectivity of benzene conversion to phenol and good productivity. However, the catalyst coked quickly - in most reported cases the catalyst lost its activity in a matter of a few hours. Another problem of the reported chemistry is the low N20-to-phenol selectivity. In fact, the stoichiometry of benzene oxidation to CO2 by N2O implies that 1% of benzene selectivity loss to deep oxidation is accompanied by 15% selectivity loss in N2O conversion. Considering that the supply of nitrous oxide is limited, the efiBciency of its utilization is very important for the commercial operation. 

Complexes (160) (see equation 35) undergo conversion to phenols upon thermolysis.Alternatively, treatment... 

Isopropylbenzene. See also Cumene conversion to phenol, 947, 969 nitration, 878... 

In many cases, it is not possible, because, of unfavorable market conditions, to obtain credit from by-product sodium sulfate. It is therefore necessary to use the partial-pressure distillation process, which entails substantially quantitative utilization of both hydrocarbon and acid by repeatedly distilling excess benzene through the acid to remove water azeotropiyally. This basic improvement was made by Guyot as a result of the gre demand for phenol during World War I, and this principle is still usedfo produce much of the benzenesulfonic acid made in the United States for conversion to phenol. In its original form, the process operated on a... 

Diazotization of 2,4-dinitroaniline in aqueous solution is accompanied by some conversion to phenols in which a nitro group is replaced by a hydroxy group. 

In order to promote selective deprotonation at C-1 in 109, an electron attracting substituent is required at the para position, C-S. The nitrile group was chosen— also because it permitted ready conversion to phenolic hydroxyl at the end of the synthesis (Scheme 15). lodination of sulfone 109 followed by iodide-cyanide exchange gave the C-5 nitrile 115. The optically active acid (-f) 103 (Scheme 14), via its methyl ester (4-) 102, was converted in good yield into iodo olefin 116. 

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