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Sodium borohydride is stable at normal temperature and pressure, and the sodium borohydride alkaline solution is brownish yellow, one of the most commonly used reducing agents. It is stable to moisture and oxygen in the air, easy to handle, and suitable for industrial scale. Because of solubility problems, methanol and ethanol are usually used as solvents. In general, sodium borohydride cannot reduce esters, amides, carboxylic acids, and nitrile compounds, but the ester can be reduced, except when a hetero atom in the alpha position of the carbonyl group of the ester is present. After contact with sodium borohydride, there are symptoms such as sore throat, cough, shortness of breath, headache, abdominal pain, diarrhea, dizziness, conjunctival congestion, and pain. Inhalation or skin contact with this agent is harmful to humans. Sodium borohydride should be stored dry and should be used with care. It should be carried out in a fume hood during operation. It should be stored in a cool, dry warehouse. Moisture-proof, shock-proof, do not store and transport with inorganic acids, away from heat and fire and flammable materials.

Sodium borohydride is contacted with carboxylic acid to rapidly decompose and release hydrogen. Therefore, it cannot reduce the carboxylic acid alone, and must be used in combination with iodine. The carboxylic acid is first reacted with the carboxylic acid until the bubble stops, and iodine is added to continue the gas release. Subsequent addition of the boric acid ester formed by the decomposition of hydrochloric acid gives an alcohol. Note: The reaction should be carried out in anhydrous tetrahydrofuran (THF). Tetrahydrofuran (THF) must be refluxed until the benzophenone turns blue to use! Otherwise a milk is formed during the reaction of the carboxylic acid with sodium borohydride, rather than a clear liquid.

After reacting sodium borohydride with anhydrous zinc chloride (dried and dried at 200 ° or more) in anhydrous tetrahydrofuran (THF) for 3 hours, zinc borohydride was obtained. The solution mixture can be used as zinc borohydride without the need for separation and purification, to reduce the carboxylic acid or ester at the reflux temperature of tetrahydrofuran (THF), the yield is good, but the double bond may be somewhat affected, such as reducing cinnamon. Acid, there will be a part of the product of double bond reduction.