How is NaBH4 prepared?

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.

What does NaBH4 reduce?

Sodium borohydride 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. It can also behave as a nucleophile toward halides and epoxides.

What does NaBH4 do to a ketone?

Sodium borohydride (NaBH4) is a reagent that transforms aldehydes and ketones to the corresponding alcohol, primary or secondary, respectively.

How do you handle NaBH4?

When handling sodium borohydride, nitrile or neoprene gloves, safety goggles and a flame retardant lab coat have to be worn. Sodium borohydride is preferably handled in a glove box or under inert atmosphere. It can also be handled on a cleared and dry space within the fume hood.

Why is NaBH4 used in excess?

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.

Is NaBH4 a catalyst?

The recent development of the NaBH4-PEMFC system lies in the development of a sodium borohydride hydrolysis catalyst, the design of a hydrogen production device, and the optimization of the system performance. This has resulted in sodium borohydride becoming the first choice of new hydrogen generation sources.

What is the difference between NaBH4 and LiAlH4?

The key difference between LiAlH4 and NaBH4 is that LiAlH4 can reduce esters, amides and carboxylic acids whereas NaBH4 cannot reduce them. Both LiAlH4 and NaBH4 are reducing agents. But LiAlH4 is a very strong reducing agent than NaBH4 because the Al-H bond in the LiAlH4 is weaker than the B-H bond in NaBH4.

How does NaBH4 reduce aldehydes?

The sixth example is a hemiacetal that opens into an aldehyde and is then reduced by NaBH4. Mechanism: NaBH4 is a source of hydride (H-) and the reaction begins with the addition of hydride to the carbonyl to the aldehyde (Step 1, arrows A and B).

What does NaBH4 and LiAlH4 reduce?

What is the main safety concern when working with NaBH4?

* Breathing Sodium Borohydride can irritate the nose and throat. * Breathing Sodium Borohydride can irritate the lungs causing coughing and/or shortness of breath. Higher exposures can cause a build-up of fluid in the lungs (pulmonary edema), a medical emergency, with severe shortness of breath.

What is a safety hazard associated with sodium borohydride?

Hazard statement(s) H260 In contact with water releases flammable gases which may ignite spontaneously. H301 + H311 Toxic if swallowed or in contact with skin H314 Causes severe skin burns and eye damage.

Is NaBH4 a reducing agent?

What it’s used for: Sodium borohydride is a good reducing agent. Although not as powerful as lithium aluminum hydride (LiAlH4), it is very effective for the reduction of aldehydes and ketones to alcohols.