Regarding the reaction of the addition substitution of halogens with benzene It s a bit confusing!!

The characteristics of benzene must be remembered: easy to substitute and difficult to add, so benzene, chlorine and bromine only undergo substitution reaction to produce chlorobenzene or bromobenzene in the case of iron catalysis, and only monovariate occurs.

Benzene can only react with pure chlorine or pure bromine, and the solution formed by chlorine water, bromine water, chlorine and bromine organic solvents is considered not to react in the presence of catalysts.

There is only one addition reaction of benzene, which is the addition of benzene and 3 molecules of hydrogen to form cyclohexane. There is only one addition reaction between benzene and halogen, that is, benzene and chlorine gas form hexachlorocyclohexane (commonly known as hexahexane) under certain conditions

Toluene, bromine and chlorine under light conditions, the substitution reaction occurs on the methyl group, and as long as the halogen is excessive, the three hydrogens on the methyl group can be substituted.

If the condition is iron-catalyzed, the substitution reaction occurs on the benzene ring, generally in the para-position of the methyl group, and when the halogen is excessive, the ortho and para-substitution of the methyl group can occur.

Toluene, like benzene, is not prone to addition reactions, and halogens generally do not undergo addition.

The substitution condition is ferric chloride catalyst (both bromine and chlorine)...How much you bring depends on the amount of chlorine you have. Bonuses are actually very hard to happen.

The benzene ring is a large conjugated system. Be in bright light. Toluene is generally substituted only on methyl groups.

Because the hydrogen on the methyl group is the allyl type of hydrogen.

In high school, I don't think I need to think about it so much. You just look at how you react to the product you want when you do the problem, and you can react well.

Halogenation reaction: Here the brominated reaction is taken as an example: Toluene reacts with liquid bromine under a trivalent iron ion (ferric bromide) catalyst. The methyl group in toluene is an ortho-para-activated group, which can improve its ortho-and para-electrophilic substitution activity, so toluene benzene ring.

on the hydrogen atom.

It is replaced by bromine atoms, mainly replacing hydrogen on carbon, mainly producing o-bromotoluene and p-bromotoluene and hydrogen bromide.

Under light conditions: Toluene reacts with gaseous bromide elemental substances, and the substituents are methyl groups in the side chain to form benzyl bromide and hydrogen bromide.

There are two problems that must be considered, one of which is the nature of the methyl group, because in fact, the ortho-para localization group, so the bromine can only go to the 2 or 4 positions, and the yield of the second, 2 and 4 products, in fact, their products are available, but the para-products are a large number, because of the steric hindrance effect. Then immediately after the nitro group, the counterpoint has been occupied, and the only way to go is to go to the neighbor position.

Here's the answer:

The benzohalogenated reaction is an electrophilic substitution reaction in a catalyst (mainly Alcl3, Fex3 and other Lewis acids.

Catalyze, halogens.

The degree of polarization of different halogens is as follows: I2>Br2>Cl2>F2.

But what determines the speed of the reaction is the decision step of the reaction. The reaction process is as follows: In the first step, the electrophile attacks the benzene ring.

Forms with delocalized electrons - complexes.

In the second step, the electrophile takes the second electron from the benzene ring to form a carbocation (complex), which is also the rate-determining step of the reaction. f ionic radius is small and electronegative.

Large, it is easier to take electrons from the benzene ring, so the order of reactivity is F2>Cl2> Br2>I2.

The benzene ring is the structure of the benzene molecule. is a planar regular hexagon, with each vertex being a carbon atom, each carbon atom and a hydrogen atom.

Combine. The carbon-carbon bond in the benzene ring is a unique bond between single and double bonds, with a bond angle of 120° and a bond length.

Halogenation, also known as halogenation, refers to the reaction in which hydrogen or other groups in organic compounds are replaced by halogens to form halogen-containing organic compounds. Halogenation plays an important role in organic synthesis, through which a variety of halogen-containing organic compounds can be prepared.

Toluene and bromine undergo a substitution reaction under light conditions, and bromine replaces methyl groups to obtain hydrogen atoms to form monobromode, dibromoide, and tribromode. Their reaction with NaOH is also a substitution reaction (hydrolysis of halogenated hydrocarbons), and the bromine atom is substituted by a hydroxyl group to produce benzyl alcohol.

c), benzaldehyde (d), benzoic acid (e). The formation of benzaldehyde is because two hydroxyl groups are connected to the same carbon and are unstable, and a molecule of water is removed, leaving one oxygen, which forms a carbon-oxygen double bond with carbon, and there is also a hydrogen on the carbon, which forms an aldehyde group. Even 3 hydroxyl groups on the carbon are unstable, and a molecule of water is also removed to form a carbon-oxygen double bond, and there is a hydroxyl group on the carbon, which forms a carboxyl group.

The C (benzyl alcohol) and E (benzoic acid) reactions are clearly esterifications. You're a middle school student, so write concentrated sulfuric acid.

Just heat it up

f is benzyl benzoate.

Toluene can be oxidized under KMno4 to form benzoic acid. Types of reactions... Oxidation reactions.

Substitution halogenation mainly includes substitution halogenation on aromatic rings, substitution of aromatic ring side chains and aliphatic hydrocarbons. Substitution of halogenation to replace chlorination and substitution of bromination are the most common.

Drip the benzene bromide mixture (benzene + liquid bromide) into a tube filled with an iron catalyst. The purpose of the bottom in and out is to create a maximum temperature difference and enhance the condensation effect. The final purpose of drying the tube is to absorb toxic HBR or BR2.

Substitution halogenation on aromatic rings is an electrophilic substitution reaction with the general formula ph-h+x2 ph-x+hx.

This is an important class of reactions in fine organic synthesis that can produce a series of important aromatic halogenated derivatives. For example, Lewis acids such as aluminum chloride, ferric chloride, ferric bromide, tin tetrachloride, and zinc chloride are commonly used as catalysts for this kind of reaction, and their role is to promote the polarization and dissociation of halogen molecules.

The halogen group is all non-metallic.

The other groups are either all metallic or the transition from non-metal to metal is not comparable.

It is an alkali metal of metal, and the density only shows an increasing trend, remember that the density of potassium metal is smaller than that of sodium metal, and this is increasing in turn.

1 Atomic Structure:

1) Similarity: The outermost shell is 1 electron.

2) Progressiveness: The number of nuclear charges increases, the number of electrons increases, and the radius of atoms increases sequentially2 Elemental properties:

1) Similarity: all are active metal elements, and the highest positive valence is +1 valence (2) Incrementality: the ability to lose electrons is enhanced sequentially, and the metallicity is enhanced sequentially 3 Elemental properties:

1) Similarity: all have strong reduction, light, soft and fusible characteristics (2) Progression: the reduction is increased sequentially, the density tends to increase, the melting boiling point decreases sequentially, and the hardness tends to decrease.

The melting point of cesium gradually decreases from lithium to caesium, which is the opposite of halogen elements. This is because metallic bonds are present in alkali metals, and metallic bonds weaken as the atomic radius increases. There are intermolecular forces in halogen elements, and the intermolecular forces increase with the increase of relative molecular weight.

4 Compound Properties:

1) Similarity: Hydroxides are both strong bases.

2) Degrading: The alkalinity of hydroxides increases sequentially.

There are two types of reactions with halogen elements, one is the halogenation reaction of -h with -h aldehyde group, and the other can occur with or without -h, that is, oxidizing aldehyde groups to obtain carboxylic acid and hydrogen halide (aqueous solution environment).

and hypohaloic acids are only redox.

Therefore, if organic synthesis requires the halogenation reaction of -H, then the aldehyde group needs to be protected first, the most common is to react with ethylene glycol in a dry HCl environment to obtain a five-membered ring compound, which can effectively protect the aldehyde group.

Hope it helps!

Upstairs didn't make it clear for a long time, everything was silent.

13.When halogenation occurs, toluene is more reactive than benzene, and benzene is more reactive than nitrobenzene, explaining why.

The halogenation of benzene is a process of electrophilic substitution, that is, the richer the electrons on the benzene ring, the more likely it is to occur as a halogenated anti-Jane. The reactivity of toluene is higher than that of benzene, because the methyl group in toluene donates electrons, and nitrobenzene has a strong electron-absorbing effect due to nitro-induced conjugation, which is difficult to react, and the activity is relatively weak.

Benzene, the simplest aromatic hydrocarbon. Molecular formula C6H6 Colorless, flammable, peculiar odor liquids.

Benzene produces thick smoke when burned. Benzene is a colorless, special aromatic smell of liquid, can be miscible with alcohol, ether, acetone and carbon tetrachloride, microsong is implicitly soluble in water.

Halogenation reaction During the reaction, the halogen molecule is heterocracked under the joint action of benzene and the catalyst Jane cherry oak, X+ attacks the benzene ring, and X- binds to the catalyst.

Take bromine as an example: the reaction requires the addition of iron powder, and iron is formed into iron tribromide under the action of bromine.

In industry, chlorine and bromine substitutes are the most important in halobenzene.