Hydrogen bromide and water

Alcohols are bases similar in strength to water and accept protons from strong acids. An example is the reaction of methanol with hydrogen bromide to give methyloxonium bromide, which is analogous to the formation of hydroxonium bromide with hydrogen bromide and water ... 

Like alkenes, the double bonds of ,/3-unsaturated acids can be brominated, hydroxylated, hydrated, and hydrobrominated, although the reactions often are relatively slow. In the addition of unsymmetrical reagents the direction of addition is opposite to that observed for alkenes (anti-Markownikoff). Thus propenoic (acrylic) acid adds hydrogen bromide and water to form 3-bromo-and 3-hydroxypropanoic acids ... 

The synthesis of metacyclophanes 4 was accomplished by thermolysis (ring expansion with elimination of hydrogen bromide and water) during vacuum distillation of the labile crude dibromocarbene adduct 3. ... 

Acids are used to combine with the ammonia formed. A large excess of alcohol is used, but the amount of water is generally kept small. Catalysts such as hydrogen chloride, hydrogen bromide, and sulfuric acid have been employed (71). 

In the late 1980s, however, the discovery of a noble metal catalyst that could tolerate and destroy halogenated hydrocarbons such as methyl bromide in a fixed-bed system was reported (52,53). The products of the reaction were water, carbon dioxide, hydrogen bromide, and bromine. Generally, a scmbber would be needed to prevent downstream equipment corrosion. However, if the focus of the control is the VOCs and the CO rather than the methyl bromide, a modified catalyst formulation can be used that is able to tolerate the methyl bromide, but not destroy it. In this case the methyl bromide passes through the bed unaffected, and designing the system to avoid downstream effects is not necessary. Destmction efficiencies of hydrocarbons and CO of better than 95% have been reported, and methyl bromide destmctions between 0 and 85% (52). 

C16-0088. When the foiiowing substances dissoive in water, what major species are present (a) sodium hydrogen carbonate (b) methanoi (c) hydrogen bromide and (d) benzoic acid... 

As in the case of hydrogen chloride, the effect of press, on the solubility of hydrogen bromide in water is not in accord with Henry s law. Thus, H. W. B. Roozeboom found that at 0°, a gram of hydrogen bromide at 5 mm. press. 2 504 at 380 mm. 2 116 at 540 mm. and 2 212 at 760 mm. press. He also examined the press.-temp, concentration curves. 

The potassium and ammonium selenibromides have been prepared by dissolving selenium dioxide in hydrobromic acid and adding either potassium or ammonium bromide. The selenibromides are orange-red in colour and are decomposed by water into selenious acid, hydrogen bromide and the alkali bromide, yielding colourless solutions.1... 

The condensation reactions of silanols are catalyzed by acids [19, 25-27,63—68, 72], Grubb measured the hydrogen chloride catalyzed silanoi condensation reaction of trimethylsilanol in methanol [19]. Lasocki and Michalska studied the effect of acid type on the condensation of dialkylsilanediols in dioxane [68]. Under anhydrous conditions, the rate of acid catalysis by strong acids (such as hydrogen bromide and perchloric acid) was directly related to the acid concentrations. The catalytic effects of weaker acids, such as hydrogen chloride, were not linearly related to the concentration. They postulated that in anhydrous dioxane, the strong acids were completely ionized while the weaker acids were not [68]. When small amounts of water were added to the solvent, all the acids behaved in a similar manner. Lasocki [64-67] extended the studies to examine the effects of alkyl or aryl substitution of silanediols on the condensation rate in aqueous dioxane [64-67]. The rate constants for acid catalyzed condensation of... 

Water, methanol, hydrogen bromide, and hydrogen iodide cleave the Te —M bond heterolytically with the bonding electon pair remaining with the tellurium atom5,6. 

At temperatures above 500 °C more than 90 % of the organic bonded bromine was converted into bromide. By adding oxygen complete breakdown to carbon dioxide, bromide and water is possible. Under supercritical water oxidation conditions more than 99 % of the organic bonded bromine was found in the aqueous phase. A formation of bromine, hydrogen bromide and dioxines as in thermal decomposition was not observed. 

In principle, process integration applies even more to direct synthesis of hydrogen peroxide, further improving the advantages over the anthraquinone route. Methanol can be used to replace water as the solvent and the dilute methanol solution obtained fed into the epoxidation reactor. Minimal purification may be required, for example for the removal of hydrogen bromide and other additives that may have been needed to increase the selectivity. 

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