Ir Analysis

EXPERIMENT 2: SODIUM BOROHYDRIDE REDUCTION OF CYCLOHEXANONE

Abstract

Ketone is actually a compound with the structure RC(=O)R', where R and R' are variety of atoms and groups of atoms. In this experiment, cyclohexanone was reduced to cyclohexanol by sodium borohydride (NaBH4). Sodium borohydride, also known as sodium tetrahydridoborate, is an inorganic compound with the formula NaBH4, act as drying agent for any solution. The actual yield and theoretical yield of cyclohexanol were calculated in order to determine the percentage yield of the compound. Based on the calculation, the percentage yield that had obtained was 59.32 %. Furthermore, the percentage of error in this experiment is 76.52 %. Also, IR spectrum’s reading had been obtained. As a conclusion, ketone group (like cyclohexanone) can be converted to alcohol group(like cyclohexanol) by using reduction reaction by sodium tetrahydridoborate (NaBH4).

Objective

To synthesize cyclohexanol from cyclohexanone by using reduction reaction with sodium borohydride.

Introduction

In aldehyde or ketone, the double bond C=O can be reduced by the presence of a transition metal catalyst to a single bond. Aldehyde will be reduced to primary alcohol whereas ketones are reduced to secondary alcohols. However based on the condition stated earlier the reduction of C=O are much slower in comparison to C=O. Instead, the most commonly used reagent for the reduction of aldehyde and ketone is sodium borohydride, NaBH4. It acts as a source of hydride ion whereby it has two valence electrons and bears a negative charge, therefore it is attracted to and then adds to the partially positive carbonyl carbon, leaving the carbonyl oxygen negatively charged. This is then followed by the reaction of alkoxide with an aqueous acid which gives the alcohol. For example, the reaction of cyclohexanone being reduced by NaBH4, will give cyclohexanol:

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Figure 1

This experiment apply the used of NaBH4 instead of H2/metal...