Ozonolysis: Study with Video Lessons, Practice Problems & Examples

Ozonolysis is a weak oxidative cleavage reaction that involves the breaking of double bonds in alkenes, resulting in the formation of ketones, aldehydes, and formaldehyde. The process adds oxygen atoms to both sides of the double bond, effectively converting it into carbonyl groups. For example, a double bond in a carbon chain can yield multiple products based on the number of carbons on either side of the cleavage. The primary reagent used is ozone (O₃), with reductive workup often performed using zinc and acetic acid or dimethylsulfide.

General properties of ozonolysis.

So now we're going to switch gears and move away from talking about strict addition reactions to talking about oxidation reactions. It turns out that double bonds can not only be added to but they can also be oxidized. What that means is that oxygens can be placed directly on them. So, what we're going to talk about is some different ways to do that and what I want to talk about right now is ozonolysis. Ozonolysis would be categorized as a reaction that is a form of weak oxidative cleavage. Basically, cleavage just means to cut something. This entire time we're going to be using our visual scissors to cut things in different pieces. There is a mechanism for ozonolysis; it's very long. If you need to know it for your professor, believe me, I'll teach it to you. But that's not going to be on this page. On this page, I just want to give you a general overview of what ozonolysis does. Ozonolysis basically slices double bonds in half and winds up making a combination of ketones, aldehydes, and formaldehyde. Why does it make each of those things? I'll explain. But think about it this way: imagine that you have a very long carbon chain with one double bond in the middle and you cut it into 2 − how many chains would you expect to have? 2. That's pretty easy. How about if I have a ring and I have a double bond in one part of it and then I snip it right there? What would I expect to get at the end... Two rings? Two chains? No, I would just expect one chain because I have a ring and I cut it in one place, so now I have one chain. These are just simple geometry questions that actually get students confused with ozonolysis. That's exactly the way this works. So here, you can see I have a 7 carbon chain with 2 places to cut. I could use scissors here and I could use scissors here. Please, the scissors reference is just to help you visualize what's going on. What winds up happening is that if we have a 7 carbon chain with 2 cuts, I'm going to wind up getting 3 pieces. I'll get one piece at the end, a piece in the middle, and a piece on the other end. Does that make sense? The number of carbons at each end is going to be the number of carbons in the product. Here along this cut, I'm splitting it off with 1 carbon at the end. Here between the two cuts, I've got 4 carbons in the middle. And then here at the top, I've got 2 carbons being chopped off. So, I'm going to expect 3 different products: a 1 carbon product, a 4 carbon product, and a 2 carbon product. Now let's look at the reagents really quick. The reagents are actually really easy for ozonolysis because it's always just going to be ozone. O3 is ozone. So anytime you see that, you know this is ozonolysis. Sometimes different professors use different reagents as the reductive workup. Some will use zin

Predict the products of the following reaction. 

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Here’s what students ask on this topic:

What is ozonolysis in organic chemistry?

Ozonolysis is a weak oxidative cleavage reaction that involves breaking double bonds in alkenes using ozone (O₃). This process results in the formation of carbonyl compounds such as ketones, aldehydes, and formaldehyde. The reaction adds oxygen atoms to both sides of the double bond, effectively converting it into carbonyl groups. The primary reagent is ozone, and the reductive workup is often performed using zinc and acetic acid or dimethylsulfide.

What are the products of ozonolysis?

The products of ozonolysis are typically ketones, aldehydes, and formaldehyde. When a double bond in an alkene is cleaved by ozone, oxygen atoms are added to both sides of the double bond, forming carbonyl groups. The specific products depend on the structure of the original alkene. For example, a double bond in a carbon chain can yield multiple products based on the number of carbons on either side of the cleavage.

What reagents are used in ozonolysis?

The primary reagent used in ozonolysis is ozone (O₃). For the reductive workup, common reagents include zinc and acetic acid or dimethylsulfide. These reagents help to reduce the ozonide intermediate formed during the reaction, leading to the final carbonyl products.

How does ozonolysis work?

Ozonolysis works by breaking the double bonds in alkenes through the addition of ozone (O₃). The reaction mechanism involves the formation of an ozonide intermediate, which is then cleaved during the reductive workup. This process adds oxygen atoms to both sides of the double bond, converting it into carbonyl groups such as ketones, aldehydes, and formaldehyde. The specific products depend on the structure of the original alkene and the number of carbons on either side of the cleavage.

What is the mechanism of ozonolysis?

The mechanism of ozonolysis involves several steps. First, ozone (O₃) reacts with the alkene to form a molozonide intermediate. This intermediate rearranges to form a more stable ozonide. During the reductive workup, the ozonide is cleaved, typically using reagents like zinc and acetic acid or dimethylsulfide, resulting in the formation of carbonyl compounds such as ketones, aldehydes, and formaldehyde. The overall process adds oxygen atoms to both sides of the original double bond.