Reflux phenol hydrogenation

In some phenols, such as a-naphthol and 9-hydroxyphenanthrene, the hydroxyl group has been replaced by hydrogen by refluxing with 57% hy-driodic acid and acetic acid (yields 52% and 96%, respectively) [226],... 

Catalytic Reactions. Phenol hydroxylation was carried out in a batch reactor using 30% aqueous H2O2 in acetone at reflux conditions at a temperature of 80 C. Hydrogen peroxide was introduced slowly via a syringe pump. The products were... 

The total hydrogenation of the copolymers utilized the diimide method (24), generated in situ from p-toluenesulfonylhy-drazide (TSH) in xylene for six hours at reflux temperature (132-134°C). In general, 5.0 moles of TSH per 100 grams of polymer were used. We have found (25) that the addition of a phenolic antioxidant such as Irganox 1010 effectively decreases the minor, but detectable side reactions. The saturation of the... 

This method for the preparation of metal alkoxides and phenoxides is of only limited usefulness given the relatively low pAa values of alcohols and even common phenols. Hence, the method is confined to the more electropositive elements where reaction can occur either directly with the alcohol or phenol or sometimes in the presence of a catalyst. For the Group I elements (Li, Na, K, etc.) the dissolution of the metal into the neat alcohol or phenol at close to reflux temperatures can lead to the pure alkoxides or phenoxides with the evolution of hydrogen (equation l).6,7... 

Dissolve 0.5 g of the phenol in 2.5 ml of pyridine, and add one equivalent of diphenylcarbamoyl chloride (or 0.4—0.5 g if the molecular weight is uncertain). Reflux the mixture for 30-60 minutes on a boiling-water bath, and then pour into about 25 ml of water. Filter the derivative, wash with a little sodium hydrogen carbonate solution and recrystallise from ethanol, toluene, light petroleum (b.p. 60-80 °C) or dichloromethane. 

Add phenol (25 g) to a solution of the ditosylamide (12.5 g, 0.026 mol) in hydrogen bromide-acetic acid (45%, 250 mL) in a single-necked round-bottomed flask equipped with a magnetic stirrer bar and a reflux condenser surmounted by an air condenser.0 Heat and stir the mixture at 80°C for 36 h. 

Twenty-one grams (0.225 mol) of phenol is dissolved in 150 ml. of dioxane, and 5.1 g. (0.222 mol) of sodium is added. The mixture is boiled under reflux in a 500-ml. round-bottomed flask until all the sodium is dissolved. Ten grams (0.0215 mol) of octachlorocyclotetraphosphaza-tetraene is added slowly to the cold solution and the mixture is boiled for 3 hours. The cold mixture is diluted with 300 ml. of diethyl ether, then placed in a separatory funnel and washed with 120 ml. of water. It is then washed successively with dilute aqueous solutions of hydrochloric acid (5%) and sodium hydrogen carbonate (5%), and again with water. The solution is dried over sodium sulfate and the solvents are evaporated. The crude product solidifies slowly and melts at about 56°. The yield is 17 g. (85%). Purification is effected by one recrystallization from a benzene-petroleum ether mixture m.p. 85 to 86°. Anal. Calcd. C, 62.3 H, 4.3 N, 6.1. Found C, 62.0 H, 4.3 N, 6.0. 

The Overall process of reduction of an alkene to an alkane, or of reduction of an alkyne to either an al-kene or an alkane, via hydroboration requires that the intermediate organoborane be protonolyzed (Section 3.10.1.1). However, simple trialkylboranes are remarkably resistant to hydrolysis. For example, trimethylborane gives only 69% of hydroxydimethylborane after 7 h at 180 °C with 1 equiv. of water. Similar resistance is shown to alcohols, phenols and amines, and even mineral acids do not completely protonolyze trialkylboranes with any ease. Thus, aqueous or anhydrous hydrogen bromide removes only one alkyl group from tributylborane after reflux for 1 h. ... 

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