Ethylene oxide with phenolic hydroxyls

Other Methods. A variety of other methods have been studied, including phenol hydroxylation by N2O with HZSM-5 as catalyst (69), selective access to resorcinol from 5-methyloxohexanoate in the presence of Pd/C (70), cyclotrimerization of carbon monoxide and ethylene to form hydroquinone in the presence of rhodium catalysts (71), the electrochemical oxidation of benzene to hydroquinone and -benzoquinone (72), the air oxidation of phenol to catechol in the presence of a stoichiometric CuCl and Cu(0) catalyst (73), and the isomerization of dihydroxybenzenes on HZSM-5 catalysts (74). 

Condensations of hydroxylic nucleophiles with ethylene oxides, when considered as a whole, probably constitute the largest single body of epoxide reactions. Included among these nucleophiles are water itself, the aliphatic Alcohols, and the aromatic alcohols or phenols. The present section will be devoted to the reactions of theee substances. 

Alkylphenol ethoxylates are important kinds of nonionic surfactants. A characteristic feature of the catalytic ethoxylation of alkylphenols is the enhanced reactivity of phenol hydroxyl for ethylene oxide in comparison with alcohols. Esters of ethylene glycol and alkylphenol behave already as an alcohol. Therefore di-, tri-, and m-mers are allowed to form only after the complete consumption of the starting material. All commercial ethoxylated alkylphenols are mixtures of oligomer-homologues having a Poisson-like distribution with some PEG and catalyst as impurities. Both alkylphenols and dialkylphenols are useful for ethoxylation as a hydrophobic moiety. Among the alkylphenols, isooctylphenol and isononylphenol are most widely used. They are synthesized by the Friedel-Crafts alkylation of phenol with butene dimer and mixture of propene trimers, respectively. 

Thus the hydrophilic end is obtained through polyethoxylation of the ring hydroxyl by its reaction with ethylene oxide under mild basic conditions. Thus the nonionic surfactants derived from alkyl phenols have the generalized structure as shown in the following (Structure 3.11). 

Starting from Benzene. In the direct oxidation of benzene [71-43-2] to phenol, formation of hydroquinone and catechol is observed (64). Ways to favor the formation of dihydroxybenzenes have been explored, hence CuCl in aqueous sulfuric acid medium catalyzes the hydroxylation of benzene to phenol (24%) and hydroquinone (8%) (65). The same effect can also be observed with Cu(II)—Cu(0) as a catalytic system (66). Efforts are now directed toward the use of Pd° on a support and Cu in aqueous acid and in the presence of a reducing agent such as CO, H2, or ethylene (67). Aromatic... 

Other glycolytic methods for PET depolymerization described in the patent literature involve reaction with an alkene oxide,36 mainly ethylene and propylene oxides, at temperatures between 120 and 160 °C. The reaction was catalysed by basic compounds sodium hydroxide, potassium hydroxide and tertiary amino alkyl phenols. The polyol mixture obtained had a hydroxyl number in the range 140-240. These polyols were blended with conventional polyols and the mixture used in the preparation of polyurethane and polyisocyanurate foams, which had better fire resistance than foams made only with conventional polyols. 

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