Sodium Borohydride Reaction Lab Report

explanatory Essay
614 words
614 words

Observations In step one, a 0.1 grams of 4-t-butylcyclohexanone and 0.2 mL of methanol was placed into a long-neck round-bottom flask. The contents were swirled and a boiling chip was placed. 0.023 grams of NaBH4 was weighed to prepare the sodium borohydride solution. Once ready, 0.6 mL of the sodium borohydride solution was added to the apparatus. The reaction was allowed to proceed for about ten minutes. During this time, 0.5 mL of 1 N HCL was chilled in a small dram vial. Once the reaction was complete, using a pipette the cold hydrochloric acid was added to the flask. In step nine, the solution was extracted three times using 0.5 mL increments of methylene chloride. To do this the contents from the flask were washed with one 0.5 mL increment …show more content…

In this essay, the author

  • Describes the process of preparing the sodium borohydride solution in a long-neck round-bottom flask.
  • Explains the formula for 4-t-butylcyclohexanone.
  • Explains that nabh4 reduces ketones to secondary alcohols by nucleophilic attack of a hydride ion on the electrophilic carbonyl carbon and protonation of the resulting alkoxide.
  • Explains that the melting point of 4-t-butylcyclohexanol recorded was 64 degrees celsius. there could be many explanations for the low percent yield.

After corking and inverting the reaction tube, the organic layer was removed and transferred to another reaction tube. Then another increment of 0.5 mL of methylene chloride was added to the first reaction tube and the extraction process was repeated. This was done a total of three times. Then in step thirteen, about five scoops of anhydrous sodium sulfate was added to the second reaction tube. Then a filter pipette was prepared and the organic solution from the second reaction tube was added to the pipette.The mixture was allowed to gravity filter and an additional 0.5 mL increment of methylene chloride was added into the pipette and the process was repeated again. Then in step 18, the collected solutions poured onto a watch glass. It was observed that the pre-weighed watch glass weighed 26.196 grams. The watch glass was placed over the beaker that was filled with 30mL of water. It was observed that it took about fifteen minutes for the solvent …show more content…

A reaction involving a decrease in oxidation state is called a reduction. An advantage of using NaBH4 is that it does not react rapidly with alcohols.1 NaBH4 may be performed using ethanol, water, methanol, or isopropanol solvent. Sodium borohydride is is much less reactive as a base or nucleophile than lithium aluminum hydride. Therefore the reaction would be able to run in methanol without concern for traces of water. 2 When using NaBH4, ketones are reduced to secondary alcohols. There are two steps that take place when doing this mechanism, the first is a nucleophilic attack of a hydride ion on the electrophilic carbonyl carbon and then a protonation of the resulting alkoxide by either water or some other acid.

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