Multiple Choice
What is the formal charge on the carbon of the following carbene?
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10. Addition Reactions
Carbene
3:56 minutesProblem 92b
Textbook Question
Dichlorocarbene can also be generated by heating sodium trichloroacetate. Propose a mechanism for the reaction.
Verified step by step guidance1
Step 1: Begin by identifying the starting material, sodium trichloroacetate (NaO−CCl3). This compound contains a trichloromethyl group attached to a carboxylate functional group.
Step 2: Upon heating, the carboxylate group undergoes decarboxylation. This process involves the loss of carbon dioxide (CO2), which is facilitated by the thermal energy provided.
Step 3: The decarboxylation results in the formation of a trichloromethyl anion (CCl3−). This intermediate is highly unstable and undergoes further reaction.
Step 4: The trichloromethyl anion (CCl3−) eliminates a chloride ion (Cl−), leading to the generation of dichlorocarbene (:CCl2). Dichlorocarbene is a reactive intermediate with a divalent carbon atom and two lone pairs.
Step 5: The final products of the reaction are dichlorocarbene (:CCl2), carbon dioxide (CO2), and sodium chloride (NaCl). The mechanism highlights the thermal decomposition and rearrangement steps leading to the formation of these products.
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Video duration:
3mKey Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Dichlorocarbene Generation
Dichlorocarbene (Br2C:) is a reactive intermediate formed during certain organic reactions. It can be generated from precursors like sodium trichloroacetate through thermal decomposition. The process involves the loss of carbon dioxide (CO2) and the formation of the dichlorocarbene species, which is crucial for various synthetic applications in organic chemistry.
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Thermal Decomposition
Thermal decomposition is a chemical reaction where a compound breaks down into simpler substances when heated. In the context of sodium trichloroacetate, heating induces the cleavage of bonds, leading to the release of CO2 and the formation of dichlorocarbene. Understanding this concept is essential for predicting the products of reactions involving heat.
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Mechanism of Reaction
A reaction mechanism describes the step-by-step sequence of elementary reactions by which overall chemical change occurs. For the generation of dichlorocarbene from sodium trichloroacetate, the mechanism involves bond breaking and formation, which can be illustrated through curved arrows in reaction diagrams. Analyzing the mechanism helps in understanding the stability and reactivity of intermediates.
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