Explain why a much better yield of primary amine is obtained from the reaction of an alkyl halide with azide ion ( - N 3 ), followed by catalytic hydrogenation. ( Hint : An alkyl azide is not nucleophilic.)

Welcome back everyone to another video, true or false. A much higher yield of a primary amine is obtained from the reaction of an alky halite with potassium thalami followed by hydrolysis because potassium thalami upon alkyl loses its nuclear velocity and thus does not react further with the alkyl Halide to form tertiary aides. So we're given our nuclear file and we have to notice that it has a negative charge. It is a strong nuclear file now because it is a strong nuclei, we're going to consider an S and two substitution reaction. Let's suppose that in a general case, we have an alkyl hide in a form of RCH two X where X is a halogen. And basically, we have to understand that in essence, two reactions, the negatively charged nitrogen attacks the electro pilic carbon followed by the loss of the living group. And we are essentially going to form the product. That's the first step that we want to consider. Now, what product are we forming? Well, essentially potassium is an iron spectator and we are simply adding CH two R. What can we tell from here? Why doesn't further calculation occur? Nitrogen still has a long pair of electrons. So in reality, we could expect another substitution reaction, right? And a formation of e tertiary aide relative to each Coronel, but this reaction doesn't take place. Now, why is that? Well, we can essentially understand that the loan pair of NIPE is actually delocalized. There are two carbel groups, right? And essentially the long pair of nitrogen is not available for the formation of the carbon nitrogen bond. We previously had two long pairs of nitrogen. One long pair was available. Now, having only one loan pair left, we cannot perform the same reaction anymore. And therefore, the given statement is true because nitrogen loses its nuclear velocity. After the first calculation stop due to the fact that its lone pair becomes delocalized and not available for the donation into the formation of the nitrogen carbon bond. Thank you for watching.

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1. A Review of General Chemistry5h 5m
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36. Synthetic Polymers1h 49m

7. Substitution Reactions

SN2 Reaction

Organic Chemistry

7. Substitution Reactions

SN2 Reaction

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3:03 minutes

Problem 17b

Textbook Question

Explain why a much better yield of primary amine is obtained from the reaction of an alkyl halide with azide ion (^-N₃), followed by catalytic hydrogenation. (Hint: An alkyl azide is not nucleophilic.)

Verified step by step guidance

Step 1: Begin by understanding the reaction sequence. The alkyl halide (CH₃CH₂CH₂Br) reacts with azide ion (N₃⁻) in a nucleophilic substitution reaction to form an alkyl azide (CH₃CH₂CH₂N=N=N). This is an SN2 reaction where the azide ion replaces the bromine atom.

Step 2: Recognize the role of the alkyl azide intermediate. The alkyl azide is not nucleophilic, meaning it does not readily react further with other nucleophiles. This prevents side reactions that could reduce the yield of the desired primary amine.

Step 3: Understand the catalytic hydrogenation step. The alkyl azide undergoes reduction in the presence of hydrogen gas (H₂) and a catalyst such as palladium on carbon (Pd/C). This process breaks the nitrogen-nitrogen bonds in the azide group, converting it into a primary amine (CH₃CH₂CH₂NH₂) and releasing nitrogen gas (N₂).

Step 4: Compare this method to other approaches for synthesizing primary amines. Direct nucleophilic substitution of an alkyl halide with ammonia often leads to over-alkylation, producing secondary and tertiary amines instead of the desired primary amine. The use of azide avoids this issue because the alkyl azide intermediate does not undergo further nucleophilic reactions.

Step 5: Conclude that the reaction sequence involving azide ion followed by catalytic hydrogenation is highly selective for producing primary amines. The lack of side reactions and over-alkylation ensures a much better yield of the desired product.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Nucleophilicity

Nucleophilicity refers to the ability of a species to donate an electron pair to form a chemical bond. In organic reactions, nucleophiles attack electrophiles, leading to bond formation. Azide ions (N3-) are strong nucleophiles, but when they form alkyl azides, the resulting compound is not nucleophilic due to the resonance stabilization of the azide group, which makes it less reactive.

Alkyl Azides

Alkyl azides are organic compounds containing an alkyl group attached to an azide functional group (-N3). They are typically formed through nucleophilic substitution reactions involving alkyl halides and azide ions. Alkyl azides are stable and can undergo catalytic hydrogenation to yield primary amines, making them useful intermediates in organic synthesis.

Catalytic Hydrogenation

Catalytic hydrogenation is a chemical reaction that involves the addition of hydrogen (H2) to a compound in the presence of a catalyst, often palladium (Pd) or platinum (Pt). In the context of alkyl azides, hydrogenation converts the azide group into an amine, resulting in a higher yield of primary amines. This process is efficient because it selectively reduces the azide without affecting other functional groups.

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