What s the most incredible rearrangement reaction you ve ever seen?

Rearrangement reaction is a chemical reaction in which the carbon skeleton of a molecule is rearranged to form structural isomers, and is a major type of organic reaction. Rearrangement reactions typically involve the transfer of substituents from one atom to another atom in the same molecule.

In the following example, the substituent r is moved from carbon atom 1 to carbon atom 2:

Intermolecular rearrangement reactions can also occur.

According to the reaction mechanism, the rearrangement reaction can be divided into: group migration rearrangement reaction and pericyclic reaction.

Group Migration Rearrangement Reaction A reaction in which one group in a reactant molecule migrates from one location to another within the molecular range. The common migration group is the hydrocarbon group. The original position of the migration group is called the migration starting point, and the migrating position is called the migration endpoint, and this kind of reaction can be divided into heterocleavage and homocleavage according to the valence bond cleavage mode, the former is much more important, especially the electron deficiency rearrangement is the most important.

In the electron-deficient rearrangement reaction, the reactant molecule first forms an electron-deficient active center at the end of migration, which promotes the migration of the migratory-cleaved electron pairs, and forms a stable product through further changes. Taking the pinacone rearrangement reaction as an example, a hydroxyl group in the reactant molecule reacts with an acid to form a zinc salt, and then loses water to become an electron-deficient active center positive carbon ion, which promotes the 1,2- migration of a methyl group with electron pairs on the hydroxyl carbon atom in the ortho-zone, and at the same time, the hydroxyl oxygen atom does not share electron pairs to transfer to the carbon and oxygen to form a double bond, and finally loses the proton to obtain the product (see the above reaction formula). After the migration endpoint forms an electron-rich active center, the migration group is transferred without bonding electron pairs, which is called the electron-rich rearrangement reaction, such as the Fawski rearrangement

a-Halogenated ketones are rearranged under the action of a strong base to form hydroxylates with different carbon frames, and the reaction is <> by negative carbon ions in the electron-rich active center

Rearrangement reaction refers to the reaction in which some groups in the organic compound molecule migrate or the carbon atom skeleton in the molecule changes under certain reaction conditions to form a new compound. Rearrangement reactions can be divided into intramolecular rearrangements and intermolecular rearrangements.

When an intramolecular rearrangement reaction occurs, the migration of the groups takes place only inside the molecule. According to its reaction mechanism, it can be divided into intramolecular electrophilic rearrangement and intramolecular nucleophilic rearrangement.

Intramolecular nucleophilic rearrangements.

Intramolecular group migration between two adjacent atoms is mostly an intramolecular nucleophilic rearrangement. For example: the decomposition of octyl bromide in ethanol;

Intramolecular electrophilic rearrangement.

Intramolecular electrophilic rearrangement reactions mostly occur on benzene rings. Common ones include benzidine rearrangement, N-substituted aniline rearrangement and hydroxyl group migration.

Under the action of acid, hydrogenated azobenzene can undergo a rearrangement reaction to form benzidine. Under acidic conditions, n-substituted aniline can migrate from nitrogen atom to ortho and para reaction of nitrogen atom. For example: the migration of nitroso, which is also an electrophilic rearrangement reaction.

Under the action of dilute sulfuric acid, OH- migration can occur, that is, OH- migrates from the branched chain to the aromatic ring as a nucleophilic site to form aminophenol. <>

Check it out for yourself:

1. Iodine clock. 2. It is a kind of resin and the liquid put is water. Coagulant plus extruder.

3. The superfluidity phenomenon of liquid helium, two wonderful properties of superfluids - penetrating the pores and climbing out of the container 4, supercooling phenomenon (supercooling): the phenomenon that the actual crystallization temperature is lower than the theoretical crystallization temperature during crystallization. At a certain pressure, when the temperature of the liquid is lower than the freezing point of the liquid at this pressure, and the liquid still does not solidify, it is called supercooled phenomena of liquid, and the liquid at this time is called supercooled liquid.

The purer the liquid, the more obvious the supercooling phenomenon is. High purity water -40 degrees Celsius before it begins to freeze. This is because the liquid is too pure to have the "crystal nucleus" needed for coagulation.

When the necessary substances are available, such as putting in a small amount of solids or shaking the liquid, the liquid can solidify quickly.

5, 7, superconducting magnetic levitation.

8. Put potassium and calcium carbide on top of ice.

9. A piece of white phosphorus, drop a drop of concentrated sulfuric acid.

10. Gases that are denser than air, at least CO2

Some of the things written upstairs aren't chemical reactions.

1. The Hofmann rearrangement reaction mechanism can be divided into two categories, namely:

A reaction in which one of the groups in the reactant molecule migrates from one location to another within the molecular range. The common migration group is the hydrocarbon group. Generally, an active center is formed in the reactant molecule, which promotes the migration of the relevant groups, and this process is also done synergistically (see Synergistic Reactions).

Through a circumferential reaction that forms a cyclic transition state, some covalent bonds in the reactant molecule are broken and others are synergistically formed (see Woodward-Hoffman's rule).

2. Group migration and rearrangement reaction The original position of the migration group is called the migration starting point, and the position after migration is called the migration endpoint, and when the two are adjacent atoms, it is 1,2 migration. This kind of reaction can be divided into heterocleavage and homocleavage according to the valence bond cleavage mode, the former is much more important, especially the electron-deficient rearrangement is the most important.

Other rearrangement reactions:

There are many similar electron-deficient rearrangement reactions, the most representative of which are: Wagner Milwein rearrangement reaction by forming positive carbon ions at the migration endpoint, Beckman rearrangement reaction by forming electron-deficient nitrogen atoms at the migration endpoint, Hoffman rearrangement reaction (reaction in which the hydrohalide of N-alkyl aniline is rearranged into aminoalkylbenzene when heated), etc.

Electron-rich rearrangement reaction After the migration endpoint forms an electron-rich active center, the migration group is promoted to transfer without bonding electron pairs, such as the Fawski rearrangement: haloketones are rearranged under the action of a strong base to form carboxylates with different carbon frames, and the reaction is carried out by negative carbon ions in the electron-rich active center.

In addition, some aromatic compounds will also undergo heterocleavage rearrangement reactions under the action of acids (see Heterocleavage reaction), such as n nitroaniline and n sulfonylaniline under the action of acids to form o-or p-nitroaniline and aminobenzene sulfonic acid rearrangement reactions, phenol carboxylate esters under the action of aluminum trichloride to form o-or p-phenol ketone flis rearrangement and hydrogenated azobenzene under the action of acid to form benzidine benzidine rearrangement.

Rearrangement reaction: One of the types of organic chemical reactions.

Please note that this is a Xunkai **in the form of splicing and repeating or withering**, if you pay attention, you will find that several acres of the process from yellow to blue first turn blue is the center of the part, and that part of the shape formed for the first time each time.

Hehe. This Xixiao is a well-known chemical ** experiment. I've done it myself... It's kio3 ki h2so4 and some other medicines.,I can't remember the specifics.。。。 You can check the book of experimental rules.

It may be that the liquid in the cup contains Huihui protein and starch, and the thing added to it may be iodine wine, which turns blue when it encounters starch, and then after heating, the iodine wine is dissipated, and the liquid is restored to the original color of the previous seepage.

The iodine clock reaction, a well-known chemical reaction, right.

Hoffman degradation reaction (also known as Hoffman rearrangement) refers to the reaction of amide with sodium hypochlorite or sodium hypobromide alkali solution to remove carbonyl groups to form a primary amine with one less carbon: R-ConH + NaOX + 2NaOH - R-NH + Na2CO + Nax + H2O

It is also called Hoffmann rearrangement reaction due to nucleophilic rearrangement during the reaction and process, and the configuration of optically active groups remains unchanged after rearrangement.

The Hoffmann degradation reaction, or Hofmann rearrangement, is an organic reaction in which a primary amide is rearranged to a primary amine and one carbon atom is reduced.

It should be correct. It's only your quiet patience that the information is incomplete. The ester you are talking about can only be phenolic esters. This type of reaction is equivalent to a Furker-acylation reaction.

This temperature is a high-temperature reaction in the organic laboratory. Regarding the products of thermodynamic control and kinetic control, the analysis is also correct. Dynamics takes into account steric hindrance.

Due to carbon negative radicals.

When attacked, the hydrogen on the carbon is rearranged and migrated to the carbon.

Rearrangement reaction: One of the types of organic chemical reactions.

Are you saying that the ketone-enol tautomerism of aldehydes and ketones has two kinds of stool hunger, one is acid-catalyzed and the other is alkali-catalyzed. Acid catalysis: alkali coarseness:

Closed regression supplement: Most of the time, this rearrangement proceeds very incompletely, with a great bias towards the ketone formula, and if there is no acid-base catalysis, the rearrangement becomes more difficult, the mechanism is that the carbonyl group first undergoes charge separation:—c=o— c(+)o(-) and then the negatively charged oxygen directly seizes the hydrogen, forming:

c(+)oh—, the negatively charged electron pairs left by the carbon are bonded with the positively charged carbonyl carbon to complete the rearrangement: —c=c—oh indecision。