Question

Tri-n-propyl borane can be converted into propyl alcohol by reaction with (1) a hydrogen peroxide at \(25-30^{\circ} \mathrm{C}\) (2) a dilute acid at reflux temperature (3) a dilute alkali at reflux temperature (4) none of these

Short answer

Option (1) is correct: Hydrogen peroxide at 25-30°C converts tri-n-propyl borane to propyl alcohol.

Step-by-step solution

Identify the reaction type

Tri-n-propyl borane can undergo oxidation reactions. Need to identify which reagent among (1), (2), (3), or (4) can facilitate this oxidation to generate propyl alcohol.

Assessing each option

Evaluate each option to determine its ability to oxidize tri-n-propyl borane: 1. Hydrogen peroxide at 25-30°C: Known to oxidize boranes to alcohols. 2. Dilute acid at reflux temperature: Typically doesn't oxidize boranes. 3. Dilute alkali at reflux temperature: Not commonly used to oxidize boranes. 4. None of these: To be considered if none of the previous options work.

Selecting the correct reagent

Hydrogen peroxide at 25-30°C is known to effectively oxidize tri-n-propyl borane to propyl alcohol, making option (1) the correct choice.

Key concepts

Oxidation Reactions

Oxidation reactions are processes where a molecule loses electrons, often involving the addition of oxygen or the removal of hydrogen. In organic chemistry, these reactions are crucial for transforming various compounds into more oxidized forms.

For instance, converting an alcohol to a ketone or an aldehyde typically involves oxidation. In our exercise, tri-n-propyl borane undergoes an oxidation reaction to become propyl alcohol. This transformation happens because oxidation breaks down the existing bonds and allows new ones, involving oxygen, to form. Understanding the mechanism of these reactions can help predict the outcome of various chemical processes and design successful industrial or laboratory reactions.

Boranes

Boranes (compounds of boron and hydrogen) play a unique role in organic chemistry. They are often intermediates in reactions that eventually produce more complex organic molecules. Boranes are especially useful for hydroboration-oxidation reactions, a method used to convert alkenes into alcohols.

In the context of the exercise, we are working with tri-n-propyl borane. As a borane, it is primed for oxidation. The reactivity of the borane compounds makes them suitable for creating various alcohols, essential for further applications in synthesis and industry. Knowing which reagents to use with boranes can significantly impact the reaction’s success, as you see with the choice of hydrogen peroxide for oxidation.

Alcohol Synthesis

Alcohol synthesis is a vital part of organic chemistry, essential for creating many products, ranging from pharmaceuticals to everyday household chemicals. There are different methods for synthesizing alcohols, each with unique reagents and conditions.

In this exercise, the synthesis of propyl alcohol involves the oxidation of tri-n-propyl borane. Such conversions are frequently achieved through specific oxidation reactions, which effectively add hydroxyl groups to carbon skeletons. This step is key for transitioning borane compounds into usable alcohols. Mastering alcohol synthesis methods is crucial for anyone studying organic chemistry, as these techniques underpin many synthetic routes in both research and industry.

Hydrogen Peroxide Reactivity

Hydrogen peroxide is a commonly used oxidizing agent in various chemical reactions, known for its effectiveness and relatively safe handling properties compared to other strong oxidizers. In organic chemistry, it's vital for reactions like the one in our exercise.

Hydrogen peroxide at a temperature range of 25-30°C is particularly known for oxidizing boranes to alcohols. This specific condition allows for controlled and efficient oxidation, leading to the creation of propyl alcohol from tri-n-propyl borane. Its ability to selectively oxidize certain groups while leaving others intact makes it an indispensable tool in organic synthesis.

By understanding how hydrogen peroxide functions in oxidation reactions, you can better predict and control the outcomes of your chemical processes, ensuring successful synthesis of the desired products.