Hydrogen bromide aqueous solution

A new method for the demethylation of codeine to morphine, previously a capricious reaction, has been reported, the product being obtained in good yield. Demethylation by boron tribromide in chloroform gives 90—91%150 and by potassium t-butoxide in propanethiol gives 80% morphine.151 A patent describes an improved method for the preparation of codeinone from thebaine, by adding the alkaloid to anhydrous hydrogen bromide in solution in methylene chloride and dibutyl ether at -20 °C, in the presence of small quantities of iodine, followed by hydrolysis with aqueous sodium bicarbonate. The claimed yields of codeinone are 95% crude and 90% after purification.152 Codeinohe is an intermediate in the conversion of thebaine into codeine. An overall yield of 85% of codeine from thebaine, without purification of any of the intermediates, has been claimed for an... 

Chemical species that induce SCC in carbon and low-alloy carbon steels, even at low concentrations include hydroxides, gaseous hydrogen, gaseous chlorine, hydrogen chloride, hydrogen bromide, aqueous nitrate solutions, hydrogen sulfide gas, MnS and MnSe inclusions in the alloy. As, Sb, and Bi ions in aqueous solution, carbon monoxide-carbon dioxide-water gas mixtures. Many of these chemical systems will crack steel at room temperatures. 

Names such as hydrobromic acid refer to an aqueous solution, and percentages such as 48% HBr denote the weight/volume of hydrogen bromide in the solution. 

It is known that the order of acidity of hydrogen halides (HX, where X = F, Cl, Br, I) in the gas phase can be successfully predicted by quantum chemical considerations, namely, F < Cl < Br < I. However, in aqueous solution, whereas hydrogen chloride, bromide, and iodide completely dissociate in aqueous solutions, hydrogen fluoride shows a small dissociation constant. This phenomenon is explained by studying free energy changes associated with the chemical equilibrium HX + H2O + HjO in the solu-... 

The flask is removed from the oil bath and cooled to room temperature. To the reaction mixture are added successively 21.4 g. (0.12 mole) of finely powdered Nduomosuccininiide (l-bromo-2,5-pyrrolidinedione) (Note 4), 50 ml. of carbon tetrachloride, and 7 drops of aqueous 48% hydrogen bromide (Note 5). The flask is heated at 70 for 10 minutes (Note 6), and the temperature of the bath is then increased to 85° until the color of the reaction becomes light yellow (ca. 1.5 hours Note 7). The reaction mixture is cooled to room temperature, and the carbon tetrachloride and excess thionyl chloride are removed under reduced pressure (Note 8). The residue is suction filtered, and the solid (Note 9) is washed several times with carbon tetrachloride (total 20 ml.) and the combined filtrate collected in a 50-rnl. flask. The solvent is removed from the solution as before, and the residue is distilled into a dry ice-cooled receiver (short-path column) to give, after a small forerun, 16.1-17.1 g. (76-80%) of 2-bromohexanoyl chloride, b.p. 44-47 (1.5 mm.) as a clear, slightly yellow oil, n12 d 1.4707. This material is of sufficient purity for most synthetic purposes (Note 10). 

Hydrogen bums in an atmosphere of bromine to give hydrogen bromide. If 135 mL of H, gas at 273 K and LOO atm combines with a stoichiometric amount of bromine and the resulting hydrogen bromide dissolves to form 225 mL of an aqueous solution, what is the molar concentration of the resulting hydrobromic acid solution ... 

Whether hydrogen bromide is anhydrous or in an aqueous solution, it combusts spontaneously when in contact with fluorine. It reacts rapidly with ozone even around -100°C. The reaction speeds up before detonating. 

They react with a solution of bromine in carbon tetrachloride by substitution and an equivalent quantity of hydrogen bromide is evolved (compare addition with unsaturated compounds). When the test is conducted with bromine water and a dilute aqueous solution of a phmiol, the sim of reaction is the separation of a sparingly soluble bromine substitution product. ... 

Hydrogen bromide, hydrogen chloride and hydrogen iodide ignite in contact with fluorine, and the cone, aqueous solutions, including that of hydrogen fluoride, also produce flame. 

Hydrogen bromide, HBr(g), is a colorless gas which dissolves in water to give hydrobromic acid, HBr(a ). The latter is a strong acid which completely dissociates in aqueous solutions giving H30 ( [Pg.442]

The classical reaction of hydrogen sulphide with nitriles in basic media is catalysed by the addition of, for example, Aliquat or tetra-n-butylammonium bromide [4], The reaction proceeds most rapidly with dilute aqueous solutions of sodium sulphide under l -2 atmospheres of hydrogen sulphide to produce thioamides in good yields (>70%). 

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