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What is the difference when following up ozonolysis with DMS (dimethyl sulfide), Zn/water, or just water? Or is there really no substantial difference at all? In my textbook, the alkenes section uses DMS or Zn/water but then in the alkynes section it uses water with no explanation as to why that happens. My professor also uses them interchangeably, which gets confusing.

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Dimethylsulfide (DMS) is commonly added to an ozonolysis reaction after it is complete (e.g. it is the first step in the reaction work-up). I can see how zinc could serve the same purpose. Both of these reagents can reduce oxidized materials. When the ozonolysis is complete the reaction contains the raw ozonide along with numerous undesirable side-products such as peroxides, hydroperoxides and tetroxanes - all of these materials are potentially explosive. The DMS or zinc will reduce them to carbonyls and alcohols and remove the explosion hazard. I suppose that tap water is somewhat acidic or basic depending upon where you live, and it might, therefore, also serve to reduce these materials.

It is one thing to say or write "add water during workup" in a lecture or text, it's another thing to actually deal with explosive materials in the lab. Personally, I wouldn't chance it. I'd use a real reducing agent such as DMS or zinc, instead of a water work-up.

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