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It is more hydrogen-dense than liquid hydrogen and also able to exist at normal temperatures and pressures. [17] Ammonia borane finds some use in organic synthesis as an air-stable derivative of diborane. [18] It can be used as a reducing agent in transfer hydrogenation reactions, often in the presence of a transition metal catalyst. [19]
The reaction commences with the formation of the aquo adduct, H 2 O−BF 3, which then loses HF that gives fluoroboric acid with boron trifluoride. [22] 4 BF 3 + 3 H 2 O → 3 H[BF 4] + B(OH) 3. The heavier trihalides do not undergo analogous reactions, possibly due to the lower stability of the tetrahedral ions [BCl 4] − and [BBr 4] −.
The reaction thus provides a more stereospecific and complementary regiochemical alternative to other hydration reactions such as acid-catalyzed addition and the oxymercuration–reduction process. The reaction was first reported by Herbert C. Brown in the late 1950s [2] and it was recognized in his receiving the Nobel Prize in Chemistry in 1979.
A closely related mixture, sometimes called "base piranha", is a 5:1:1 mixture of water, ammonia solution (NH 4 OH, or NH 3 (aq)), and 30% hydrogen peroxide. [2] [3] As hydrogen peroxide is less stable at high pH than under acidic conditions, NH 4 OH (pH c. 11.6) also accelerates its decomposition.
This chemical reaction is useful in the organic synthesis of organic compounds. [1] Hydroboration produces organoborane compounds that react with a variety of reagents to produce useful compounds, such as alcohols, amines, or alkyl halides. The most widely known reaction of the organoboranes is oxidation to produce alcohols from alkenes.
This hydrogen peroxide then releases hydrogen peroxide: [(HO) 3 B(OOH)] − + H 2 O ⇌ B(OH) − 4 + H 2 O 2. Several metal hydroperoxide complexes have been characterized by X-ray crystallography. Some form by the reaction of metal hydrides with oxygen gas: [17] L n M−H + O 2 → L n M−O−O−H (L n refers to other ligands bound to the ...
In the wash, both compounds dissolve in the water. When dissolved in water, the persalt releases hydrogen peroxide (e.g. from sodium percarbonate): 2Na 2 CO 3 ∙3H 2 O 2 → 2Na 2 CO 3 + 3H 2 O 2. In a basic wash solution, hydrogen peroxide loses a proton and is converted to the perhydroxyl anion: H 2 O 2 ⇌ H + + HO 2 −
Borane ammoniate, which is produced by a displacement reaction of other borane adducts, eliminates elemental hydrogen on heating to give borazine (HBNH) 3. [12] Borane adducts are widely used in organic synthesis for hydroboration, where BH 3 adds across the C=C bond in alkenes to give trialkylboranes: [13] (THF)BH 3 + 3 CH 2 =CHR → B(CH 2 CH ...