Reactions of Alkynes. Reactions of Alcohols. Reactions of Aromatic Compounds. Reactions of Aldehydes and ketones. I am working on covering all the topics of Org I and II and t he list is ever-growing.
You will receive an e-mail with any newly-added files as they appear! Notify me of followup comments via e-mail. You can also subscribe without commenting. Aldehydes and Ketones Cheat Sheet — A Beautiful PDF to Download This cheat sheet study guide summarizes the reactions of aldehydes and ketones lay the foundation of understanding the nucleophilic addition reactions to many carbonyl compounds such as esters, acid chlorides, anhydrides, and others.
Just so you can see how awesome these are. Oxidations of aldehydes and ketones. Aldehydes can be oxidized to carboxylic acid with both mild and strong oxidizing agents. However, ketones can be oxidized to various types of compounds only by using extremely strong oxidizing agents.
Typical oxidizing agents for aldehydes include either potassium permanganate KMnO 4 or potassium dichromate K 2 Cr 2 O 7 in acid solution and Tollens reagent. Peroxy acids, such as peroxybenzoic acid:. For example, peroxybenzoic acid oxidizes phenyl methyl ketone to phenyl acetate an ester. Aldol reactions. In addition to nucleophilic additions, aldehydes and ketones show an unusual acidity of hydrogen atoms attached to carbons alpha adjacent to the carbonyl group.
The electron withdrawing ability of a carbonyl group is caused by the group's dipole nature, which results from the differences in electronegativity between carbon and oxygen.
The resonance, which stabilizes the anion, creates two resonance structures — an enol and a keto form. In most cases, the keto form is more stable. Halogenation of ketones. Likewise, when methyl ketones react with iodine in the presence of a base, complete halogenation occurs. The generation of sodium hypoiodate in solution from the reaction of iodine with sodium hydroxide leads to the formation of iodoform and sodium benzoate, as shown here.
Because iodoform is a pale yellow solid, this reaction is often run as a test for methyl ketones and is called the iodoform test. Aldol condensation. The aldol condensation proceeds via a carbanion intermediate. The carbanion undergoes nucleophilic addition with the carbonyl group of a second molecule of ethanal, which leads to formation of the condensation product.
Cross-aldol condensation. Ketonic aldol condensation. With acid catalysts, however, small amounts of aldol product can be formed. This dehydration step drives the reaction to completion. The mechanism proceeds as follows:. Cyclizations via aldol condensation. Internal aldol condensations condensations where both carbonyl groups are on the same chain lead to ring formation.
The mechanism for cyclization via an aldol proceeds through an enolate attack on the aldehyde carbonyl. The benzoin condensation. The cyanide ion is the only known catalyst for this condensation, because the cyanide ion has unique properties.
For example, cyanide ions are relatively strong nucleophiles, as well as good leaving groups. The test tubes have been stirred to get homogeneous solution. As it showed no changes, the test tubes will be heat by placing them in a beaker that contains water on the hotplate. In about 5 minutes the result was observed. Stoppered the test tubes to shake it vigorously to see formation of emulsion. Result was observed. Iodoform test 1.
Iodine solution was added drop by drop until the colour of iodine stays. Grey solution formed. The solution in the test tubes has been mix slowly to see the results 6. As it showed no changes of the solution into silver mirror, the test tubes will be heat by placing them in a beaker that contain with hot water on the hotplate.
The solution in the test tubes has been mix slowly to see the results. The result was observed. Iodoform test Solution Observation A Colourless solution turns into yellow B Colourless solution turns into yellow C Yellow precipitate was formed D Yellow colour layer formed on top of the solution d.
Write equation involved. Answer: 2-butanone will turn into aldehyde while the 2-methylbutanal turns into ketone. The different in the structure of aldehydes compared to ketones is the hydrogen that attach to the aldehydes as ketones do not have the hydrogen atom.
Due to resonance, it becomes a strong bond and oxidizing agent that cuprum unable to oxidize it. Oxidation of Aldehydes and Ketone, b. Aliphatic aldehydes restore the pink immediately, whereas aromatic ketones have no effect on the reagent. Aromatic aldehydes restore the colour slowly.
For this experiment, 4 test tube with different unknown in each test tube labelled as A, B, C, D. A few drops of schifff reagent has been added to each test tube. Booth test tubes are shaken gently. For test tube A, reagent color change into dark purple.
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