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Sodium Borohydride is a white, odorless powder or pellet. It is used for bleaching wood pulp, as a blowing agent for plastics, and as a reducing agent for aldehydes and ketones.
In the Brown-Schlesinger process sodium borohydride is industrially prepared from sodium hydride (produced by reacting Na and H2) and trimethyl borate at 250–270 °C: B(OCH3)3 + 4 NaH → NaBH4 + 3 NaOCH. Millions of kilograms are produced annually, far exceeding the production levels of any other hydride reducing agent.
Sodium borohydride is a relatively selective reducing agent. Ethanolic solutions of sodium borohydride reduce aldehydes and ketones in the presence of epoxides, esters, lactones, acids, nitriles, or nitro groups. 27 , 33. Reduction of aldehydes is straightforward.
Aldehydes and Ketones are reduced by most reducing agents. Sodium borohydride and lithium aluminumhydride are very common reducing agents. Ketones and Aldehydes can also be reduced to the respective alkanes.
NaBH4 is less reactive than LiAlH4 but is otherwise similar. It is only powerful enough to reduce aldehydes, ketones and acid chlorides to alcohols: esters, amides, acids and nitriles are largely untouched.
When sodium borohydride is in a strongly basic solution (at or above pH 10), it is stabilized against reaction with water, although addition of water may still be exothermic due to heat of solvation. At lower pH levels, sodium borohydride reacts exothermically with water to generate flammable hydrogen gas.
It is not necessary to exclude moisture nor atmospheric oxygen when using NaBH4. … This is the main reason why a slight excess of sodium borohydride is used customarily in reduction reactions. NaBH4 is above all used for reducing aldehydes and ketones. Aldehydes can be reduced selectively in the presence of ke- tones.
Sodium borohydride is a white to grayish crystalline powder. It is decomposed by water to form sodium hydroxide, a corrosive material, and hydrogen, a flammable gas. … Sodium borohydride is an inorganic sodium salt and a metal tetrahydridoborate.