Oxidative 2- phenols, silver© oxide

Oxidative coupling of phenols Silver carbonate precipitated on Celite is an excellent reagent for oxidative coupling of phenols thus 2,6-dimethylphenol (1) gives thep-diphenoquinone (2) in 98% yield. 

PHOSPHORIC ACID, DIMETHYL ESTER, WITH (E)-3-HYDROXY-A, A -DIMETHYLCROTONAMIDE (141-66-2) CsHisNOjP May react violently with antimony(V) pentafluoride. Inconqiatible with nitrates. Corrosive to cast iron, mild (low carbon) steel, brass, and stainless steel 304. Slow hydrolysis in water. Decomposes in storage at temperatures above 135°F/55°C. Incompatible with organic anhydrides, acrylates, alcohols, aldehydes, alkylene oxides, substituted allyls, cresols, caprolactam solution, epichlorohydrin, ethylene dichloride, glycols, isocyanates, ketones, lead diacetate, magnesium, maleic anhydride, nitrates, nitromethane, phenols, silver nitrate, vinyl acetate. 

Trilialophenols can be converted to poly(dihaloph.enylene oxide)s by a reaction that resembles radical-initiated displacement polymerization. In one procedure, either a copper or silver complex of the phenol is heated to produce a branched product (50). In another procedure, a catalytic quantity of an oxidizing agent and the dry sodium salt in dimethyl sulfoxide produces linear poly(2,6-dichloro-l,4-polyphenylene oxide) (51). The polymer can also be prepared by direct oxidation with a copper—amine catalyst, although branching in the ortho positions is indicated by chlorine analyses (52). 

In small-scale syntheses, a wide variety of oxidants have been employed in the preparation of quinones from phenols. Of these reagents, chromic acid, ferric ion, and silver oxide show outstanding usefulness in the oxidation of hydroquinones. Thallium (ITT) triduoroacetate converts 4-halo- or 4-/ f2 -butylphenols to l,4-ben2oquinones in high yield (110). For example, 2-bromo-3-methyl-5-/-butyl-l,4-ben2oquinone [25441-20-3] (107) has been made by this route. 

Formaldehyde, produced by dehydrogenation of methanol, is used almost exclusively in die syndiesis of phenolic resins (Fig. 7.2). Iron oxide, molybdenum oxide, or silver catalysts are typically used for preparing formaldehyde. Air is a safe source of oxygen for this oxidation process. 

Peroxodisulfate ions oxidize aromatic amines md phenols to colored derivatives, paitic ularly under the catalytic influence of silver ions [1-4]. 

Alkyl halides in the presence of silver oxide will convert any non-hindered carboxylic acid (or its salt) to the corresponding alkyl ester in minutes, and phenolic or thiol groups will also be alkylated rapidly [436]. Hydroxyl groups are alkylated slowly an ot always to completion. The alkyl halides most frequently uJQp are the lower molecular weight aliphatic... 

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