9.8 Ozonolysis of Alkynes | Organic Chemistry

Chad's Prep
11 Dec 202003:51
EducationalLearning
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TLDRThis video script provides an insightful lesson on the analysis of alkynes, focusing on the ozonolysis of alkenes as a starting point. The lesson explains that ozonolysis, an oxidative cleavage reaction, can be applied to alkynes as well, where a carbon-carbon triple bond is cleaved instead of a double bond. Under oxidizing conditions, the reaction results in the formation of carboxylic acids. The video differentiates between internal and terminal alkynes, noting that terminal alkynes yield one carboxylic acid and carbon dioxide due to further oxidation of formic acid. The presenter encourages viewers to subscribe for weekly updates and offers additional resources on chadsprep.com for further study and practice.

Takeaways
  • 📚 The lesson focuses on the analysis of alkynes, specifically their oxidative cleavage, similar to ozonolysis of alkenes but targeting a carbon-carbon triple bond instead of a double bond.
  • ⏰ The series of organic chemistry lessons will be released weekly throughout the 2020-21 school year, encouraging subscribers to stay updated.
  • 🔄 Ozonolysis of alkenes involves cleaving a carbon-carbon double bond and replacing it with carbon-oxygen double bonds, resulting in either a ketone or an aldehyde, depending on the conditions.
  • ➡️ Under reducing conditions, dimethyl sulfide or zinc and water are used, yielding a ketone product.
  • 🧪 Under oxidizing conditions with hydrogen peroxide, aldehydes are further oxidized to carboxylic acids, while ketones remain unchanged.
  • 🔍 For alkynes, ozonolysis is only performed under oxidizing conditions, using water instead of peroxide, leading to the formation of carboxylic acids.
  • 📈 Predicting products from alkyne ozonolysis involves cleaving the carbon-carbon triple bond, which results exclusively in carboxylic acids, not ketones or aldehydes.
  • 🔑 In the case of an internal alkyne, the cleavage results in two carboxylic acids, corresponding to the number of carbons on each side of the broken triple bond.
  • ⏹ For terminal alkynes, the ozonolysis process leads to one carboxylic acid and carbon dioxide, as the formic acid produced is further oxidized to CO2.
  • 👍 The presenter encourages viewers to like and share the lesson if they found it helpful, promoting the channel and its content.
  • ❓ The comment section is open for questions, and additional resources such as study guides, practice problems, and a rapid review for organic chemistry exams are available on chadsprep.com.
Q & A

  • What is the main topic of the lesson?

    -The main topic of the lesson is the analysis of alkynes.

  • How is ozonolysis of alkynes similar to ozonolysis of alkenes?

    -Both ozonolysis of alkynes and alkenes involve an oxidative cleavage reaction, where a carbon-carbon multiple bond is cleaved and replaced with carbon-oxygen double bonds.

  • What are the two possible conditions under which ozonolysis can be performed?

    -Ozonolysis can be performed under reducing conditions or oxidizing conditions.

  • What is the role of dimethyl sulfide or zinc and water in the ozonolysis process?

    -Dimethyl sulfide or zinc and water are used in the second step of ozonolysis under reducing conditions to produce the final products.

  • What happens to aldehydes under oxidizing conditions during ozonolysis?

    -Under oxidizing conditions, aldehydes are further oxidized to carboxylic acids.

  • What is unique about performing ozonolysis on alkynes?

    -Ozonolysis on alkynes is only ever performed under oxidizing conditions, and instead of using hydrogen peroxide, water is used in the second step.

  • What are the products formed when an internal alkyne undergoes ozonolysis?

    -When an internal alkyne undergoes ozonolysis, the products are two carboxylic acids, with the carbons of the triple bond being the carbons of the carboxylic acids in the products.

  • What is the difference in the ozonolysis products of a terminal alkyne compared to an internal alkyne?

    -In the case of a terminal alkyne, instead of two carboxylic acids, one carboxylic acid and carbon dioxide are produced due to the further oxidation of formic acid.

  • Why is formic acid not a product in the ozonolysis of terminal alkynes?

    -Formic acid is not a stable product under ozonolysis conditions and is further oxidized to carbon dioxide.

  • What does the instructor suggest doing if the lesson was helpful?

    -The instructor suggests giving a like and a share if the lesson was helpful.

  • Where can one find study guides, practice problems, and a final exam rapid review for organic chemistry?

    -Study guides, practice problems, and a final exam rapid review for organic chemistry can be found as part of the instructor's premium course on chadsprep.com.

  • How can viewers stay updated with the instructor's future lessons?

    -Viewers can subscribe to the channel and click the bell notification to be alerted every time a new lesson is released.

Outlines
00:00
🌟 Introduction to Alkynes Analysis and Ozonolysis Review

The video begins by introducing the topic of alkynes analysis, which will be the focus of the lesson. It then reviews the ozonolysis of alkenes, highlighting the similarities and differences between the cleavage of a carbon-carbon double bond and a triple bond. The presenter mentions that the lesson is part of an organic chemistry playlist that will be released weekly throughout the 2020-21 school year. They encourage viewers to subscribe to the channel and turn on notifications to stay updated with new content. The summary of ozonolysis explains the process under both reducing and oxidizing conditions, resulting in the formation of ketones or aldehydes, which can further oxidize to carboxylic acids. The video then transitions into discussing the specific process of ozonolysis for alkynes, which only occurs under oxidizing conditions using water, leading to the formation of carboxylic acids.

Mindmap
Keywords
💡Alkynes
Alkynes are unsaturated hydrocarbons that contain at least one carbon-carbon triple bond. They are the focus of the video, which discusses their analysis, particularly in the context of ozonolysis. Alkynes are important in organic chemistry due to their reactivity and the variety of products that can be formed from their reactions.
💡Ozonolysis
Ozonolysis is a chemical reaction where an alkene or alkyne reacts with ozone, leading to the cleavage of the carbon-carbon double or triple bond. In the video, ozonolysis is compared between alkenes and alkynes, highlighting the differences in the products formed due to the nature of the bond being cleaved.
💡Carbon-Carbon Triple Bond
A carbon-carbon triple bond is a covalent bond between two carbon atoms where six electrons are shared, represented by a triple line between the carbon atoms. The video discusses the cleavage of this bond during the ozonolysis of alkynes, which is a key step in the reaction and differentiates it from the ozonolysis of alkenes.
💡Organic Chemistry
Organic chemistry is the study of carbon-containing compounds and their reactions. The video is part of an organic chemistry playlist, indicating that the concepts discussed, such as alkynes, ozonolysis, and the formation of carboxylic acids, are central to the field of organic chemistry.
💡Carboxylic Acids
Carboxylic acids are a class of organic compounds containing a carboxyl functional group (-COOH). The video explains that the products of ozonolysis of alkynes are primarily carboxylic acids, which can vary in length depending on the structure of the alkyne. This is a significant outcome of the reaction and a key point in the video.
💡Terminal Alkyne
A terminal alkyne is an alkyne with the triple bond at the end of the carbon chain. The video differentiates the ozonolysis of terminal alkynes from internal alkynes, noting that terminal alkynes yield a carboxylic acid and carbon dioxide, whereas internal alkynes yield two carboxylic acids.
💡Formic Acid
Formic acid is the simplest carboxylic acid with the formula HCOOH. In the context of the video, formic acid is mentioned as an intermediate product in the ozonolysis of terminal alkynes, which is further oxidized to carbon dioxide under the reaction conditions.
💡Carbon Dioxide
Carbon dioxide (CO2) is a colorless, odorless gas that results from the oxidation of formic acid during the ozonolysis of terminal alkynes, as discussed in the video. It is an important product to consider when analyzing the complete reaction pathway of terminal alkynes.
💡Oxidizing Conditions
Oxidizing conditions are chemical conditions that favor the oxidation of a substance. In the video, it is mentioned that ozonolysis of alkynes is performed under oxidizing conditions, which affects the final products of the reaction, leading to the formation of carboxylic acids and carbon dioxide.
💡Dimethyl Sulfide
Dimethyl sulfide (DMS) is an organosulfur compound used in the reduction step of ozonolysis under reducing conditions. The video contrasts the use of DMS with the use of oxidizing conditions, highlighting the different outcomes for alkenes and alkynes.
💡Hydrogen Peroxide
Hydrogen peroxide (H2O2) is a mild oxidizing agent used in the second step of ozonolysis under oxidizing conditions. The video notes that while hydrogen peroxide is used for alkenes, water is sufficient for the second step of ozonolysis with alkynes.
Highlights

The lesson focuses on the analysis of alkynes, specifically the ozonolysis of alkenes and its similarity to oxidative cleavage reactions.

Cleaving a carbon-carbon double bond in alkenes is compared to cleaving a carbon-carbon triple bond in alkynes.

Ozonolysis of alkenes can be performed under both reducing and oxidizing conditions, leading to different products.

Under reducing conditions, dimethyl sulfide or zinc and water are used, resulting in a ketone or aldehyde.

Oxidizing conditions with hydrogen peroxide convert aldehydes to carboxylic acids.

Ozonolysis of alkynes is always performed under oxidizing conditions, using water instead of peroxide.

Products of alkyne ozonolysis are carboxylic acids, not ketones or aldehydes.

Internal alkynes yield two carboxylic acids upon cleavage of the carbon-carbon triple bond.

Terminal alkynes result in one carboxylic acid and carbon dioxide due to further oxidation of formic acid.

Formic acid, a potential product of terminal alkyne ozonolysis, is unstable and oxidizes further to carbon dioxide.

The lesson is part of an organic chemistry playlist released weekly throughout the 2020-21 school year.

Subscribing to the channel and clicking the bell notification ensures viewers are updated with each new lesson release.

The lesson provides a method to predict the products of ozonolysis reactions for both internal and terminal alkynes.

The channel encourages viewers to like, share, and subscribe to support and promote the content.

Questions and feedback are welcome in the comment section below for further discussion and clarification.

Additional study materials, practice problems, and a rapid review for organic chemistry are available on the instructor's website.

The instructor offers a premium course for a more comprehensive learning experience.

Transcripts

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Organic ChemistryAlkynesOzonolysisCleavage ReactionCarbon-Carbon BondCarboxylic AcidsEducational ContentChemistry PlaylistSchool Year SeriesOxidizing ConditionsChemical AnalysisAcademic Lessons