Isn t the substitution reaction characteristic of alkanes? Why is benzene OK too?

Substitution reaction is a characteristic of hydrocarbons, and substitution reactions can occur in both organic matter.

Your teacher said that it is the characteristics of alkanes, yes, our teacher also said so, in fact, as long as there are covalent bonds, they can be replaced, alkenes and alkynes can be, but the substitution of alkenes and alkynes is more complicated, so there is no need to consider it.

Substitution reaction is characteristic of alkanes.

The substitution reaction of other hydrocarbons occurs on the basis of addition reaction, while benzene and nitric acid occur with -NO2 of nitric acid in the case of sulfuric acid catalysis, and there must be substituents.

There must be substituents! More oxidizing than the substituted group!

That's fine.

Alkanes can be, and so can benzene.

The characteristic reaction you said.

If compared with alkenes and alkynes, we can say that the substitution reaction is a characteristic reaction of alkanes, which is in a state where the general requirements are not too strict.

Because the benzene ring is between the carbon-carbon single bond and the carbon-carbon double bond, that is, it has the properties of a single bond and a double bond, so it can undergo a substitution reaction like an alkane.

The substitution of alkynes is not considered at the high school level.

Then only saturated hydrocarbons in the hydrocarbons are substituted.

So substitution reactions are characteristic reactions of saturated hydrocarbons.

A lot of organic matter can be replaced, not just alkanes.

Although benzene has 4 unsaturations, it has a delocalized bond. Therefore, it is relatively stable, and hydrogen substitution occurs under halogen light.

Benzene and Br2 substitution reactions, esterification, etc. can also be classified as substitution reactions.

It can occur very little in the species reaction.

Olefins can undergo substitution reactions. The conditions under which the substitution reaction of olefins can occur: heating, pressurization, catalyst.

In an olefin molecule, the 6 atoms attached to the double-bonded carbon atom are in the same plane, while the other atoms are not necessarily in that plane. Olefins contain carbon-carbon double bonds, which can undergo addition reactions, and if the olefins also contain other atoms such as alkyl groups, substitution reactions can also occur under certain conditions, and olefins contain carbon-carbon double bonds, which can not only fade bromine water but also fade acidic KMNO4 solution.

Uses of olefinsThe uses of olefins are: used as fragrances, used in the production of polyolefins and synthetic rubber. Olefins refer to hydrocarbons that contain C=C bonds (carbon-carbon double bonds).

Olefins are unsaturated hydrocarbons and are divided into chain olefins and cyclic olefins. Olefins are called monoolefins, diolefins, etc. according to the number of double bonds. One of the double bonds is a high-energy bond, which is unstable and easy to break, so an addition reaction occurs.

Single-stranded olefins are non-polar molecules, insoluble or slightly soluble in water. The double bond group is a functional group in the olefin molecule, which is reactive, and can undergo addition reactions such as hydrogenation, halogenation, hydration, halohydrogenation, hypohalogenation, sulfate, epoxidation, polymerization, etc., and can also oxidize the cleavage of double bonds to generate aldehydes, carboxylic acids, etc.

The above content refers to Encyclopedia-Olefins.

The main reason for the alkylation reaction of benzene is the aromatization and electronic structure of benzene. Benzene has a conjugated electronic system in which the electrons are shared by the carbon atoms in the aromatic ring. This electron sharing results in a benzene ring with high stability and aromaticity.

When benzene reacts with an alkylation reagent, the alkyl group in the reagent can replace the hydrogen atom on the benzene ring to form an alkylbenzene compound. This reaction is known as alkylation. The main reasons for the alkylation reaction of benzene are the following:

1.Destruction of aromatic stability: During the alkylation reaction of benzene, an alkyl group is introduced into the benzene ring, which destroys the aromatic stability of the benzene stool.

By substituting the hydrogen atoms on the benzene ring, the conjugated electronic system is interrupted, resulting in a decrease in aromaticity. This allows the reaction to take place in the presence of alkylation reagents.

2.Nucleophilicity of alkylation reagents: Alkylation reagents (e.g., halated alkanes, alkyl halides) are nucleophilic and able to react with electrons in benzene.

The alkyl group in the alkylation reagent has a positive charge and can form an electrophilic-nucleophilic reaction with the electrons of benzene, thereby replacing the hydrogen atom on the benzene ring.

It should be noted that the alkylation reaction of benzene usually requires the use of acid catalysts (such as aluminum chloride, ferric chloride, etc.) or negative ion catalysts (such as methylene phenyllithium) to facilitate the reaction. These catalysts help to disrupt the aromaticity of the benzene ring, allowing the alkylation reaction to proceed smoothly.

In conclusion, the aromaticity of benzene and the nucleophilicity of alkylation reagents are the main causes of alkylation reactions in benzene. The result of this reaction is the introduction of an alkyl group on the benzene ring, forming an alkylbenzene compound.

The reactions that can occur between olefins and halogen elements are addition reaction and substitution reaction.

As long as there are hydrogen atoms attached to the olefin carbon, it can substitute with chlorine and bromine under light conditions. One halogen atom replaces one hydrogen, and the other hydrogen combines with another halogen atom to form hydrogen halide.

There are carbon-carbon double bonds in olefins, and when carbon-carbon double bonds encounter halogen elements, such as bromine water or bromine elements, the double bonds will open, and a bromine atom will be added on one side to form dibromohalogenated hydrocarbons.

The nitrification reaction of benzene is not the same as the type of implicit reaction of halogenation of alkanes.

Although the nitrification reaction of benzene and the halogenation reaction of alkanes are both substitution reactions, the reaction mechanism is completely different. The nitrification reaction of benzene belongs to the cationic mechanism, and the nitric acid is old under the catalysis of sulfuric acid, forming nitrogen dioxide cations, attacking the benzene ring, and finally the hydrogen ions are left to form nitrobenzene, which belongs to the cationic reaction mechanism. The halogenation reaction of alkanes belongs to the free radical reaction mechanism.

Under the action of light or free radical initiators, halogens form halogens that are self-depleted by the group, seize the hydrogen on the alkane, and form alkane free radicals, which is a chain reaction of free radicals.

Chemical equilibrium refers to a chemical reaction in a reversible reaction with certain macroscopic conditions.

Forward and reverse reaction rates.

Equal, the concentration of reactants and products does not change the degree of concentration. It can be judged by δrgm = 0, A is the chemical formula of substance A in the reaction. According to Le Chatre's principle.

If an equilibrium system is changed, the system will change to counteract the change.

The positive reaction rate and the reverse reaction rate are auspicious, clearing, etc., and the concentration of reactants and products do not change, and a state of surface quiescence is reached, which is called a chemical equilibrium state.

The four chemical equilibrium commonly referred to as redox are redox.

Equilibrium, precipitation-dissolution equilibrium, coordination equilibrium, acid-base equilibrium. Chemical equilibrium in analytical chemistry.

has extremely important applications.

Extended information: Characteristics of analytical chemistry.

1.The concept of "quantity" is highlighted in analytical chemistry.

For example, the measured data should not be arbitrarily selected; The accuracy of the data and the size of the deviation are related to the analysis method used.

2.Analyzing a specimen is a process of obtaining information and reducing the uncertainty of the system.

3.Experimental.

Emphasizing hands-on ability, cultivating experimental operation skills, and improving the ability to analyze and solve practical problems.

4.Comprehensive.

Involving chemistry, biology, electricity, optics, computers, etc., reflecting ability and quality.

Analytical chemists should have a strong sense of responsibility.

OK. The industrial production of vinyl chloride is a substitution reaction.

Olefins are hydrocarbons that contain C=C bonds (carbon-carbon double bonds) (alkene bonds). It is an unsaturated hydrocarbon, which is divided into chain olefins and cyclic olefins. According to the number of double bonds, they are called monoolefins, diolefins, etc.

One of the double bonds is easy to break, so an addition reaction occurs. The general formula of single-stranded olefin molecule is CNH2N, and C2-C4 is gas at room temperature, which is a non-polar molecule, insoluble or slightly soluble in water. The double bond group is a functional group in the olefin molecule, which is reactive, and can undergo addition reactions such as hydrogenation, halogenation, hydration, halohydrogenation, hypohalogenation, sulfate, epoxidation, polymerization, etc., and can also oxidize the cleavage of double bonds to generate aldehydes, carboxylic acids, etc.

It can be prepared by the reaction of alkyl halide and sodium hydroxide alcohol solution

RCH2CH2X + NaOH - alcohol) RHC = CH2+ NAx + H2O (X is chlorine, bromine, iodine).

It can also be prepared by alcohol loss of water or by the reaction of o-dihaloalkane with zinc. Small molecule olefins are mainly derived from petroleum cracking gas. Cyclic olefins are abundant in essential oils of plants, and many can be used as fragrances.

Olefins are important basic raw materials in organic synthesis and are used to make polyolefins and synthetic rubber.

The general formula of the olefin is: C nh 2n (n 2).

Olefins are unsaturated chain hydrocarbons containing "c=c".

The physical properties of olefins can be compared with alkanes. The physical state is determined by the mass of the molecule. In standard or room temperature, ethylene, propylene, and butene are gases in simple olefins, linear olefins containing 5 to 18 carbon atoms are liquids, and higher olefins are waxy solids.

Under standard conditions or at room temperature, C2 and C4 olefins are gases; C5 and C18 are volatile liquids; C19 or above solids. In n-olefins, the boiling point increases as the relative molecular weight increases. The boiling point of n-olefins with the same carbon number is higher than that of alkenes with branched chains.

For alkenes with the same carbon frame, the double bond moves from the end of the chain to the middle of the chain, and the boiling point and melting point increase.

Yes, hydrogen at both ends of a carbon-carbon double bond is not easy to be replaced, but other hydrogen atoms on propylene, for example, can be easily replaced.

It depends on what kind of olefin.

If it is ethylene, it is not possible, think propylene, butene, which have an alkyl part, can replace the hydrogen on the alkyl group, just like the ordinary substitution, that is to say, the double bond can only be added, not replaced.

Yes, but the reaction is more difficult to occur.

Substitution reaction: The reaction of CH4 and Cl2 is the equation CH4+Cl2=CH3Cl+HCl, CH3Cl+Cl2=CH2Cl2+HCl, CH2Cl2+Cl2=CHCL3+HCl, CHCL3+Cl2=CCl4+HCl The state of the reactant: pure halogen element and () That is, only the vapor of pure halogen element is mixed with methane and other alkane gas, and the substitution reaction is easy to occur Aqueous solution of methane and halogen elemental () If it is an aqueous solution with halogen elements, gaseous alkanes such as methane do not undergo substitution reaction, while liquid alkanes undergo an extraction process Halogen elements are generally selected Cl2, F2 and CH4 reflect too violently, and BR2, I2 and CH4 react too slowly, Fluorine gas is the most active, and the reaction is the most intense Substitution reaction characteristics:

The substitution reaction is carried out by () and () The substitution reaction is up and down, and it occurs at the same time So the chlorine of methane is not one, but (), there are 4 chlorides of methane In the appellate reaction, for every 1molh of substitution, there is () molCl2 to participate in the reaction, 1mol chlorine reaction, because in Cl2, only 1 Cl replaces 1 h to produce () molHCL. Characteristics of generating 1molHCl products: generally obtain a mixture of CH3Cl, CH2CI2, CHCL3, CCL4, four substitute products, in which () is gaseous at room temperature, and it is in () state, and the total amount of the four substitution products is equal to the amount of ().

The larger the molecular weight, the higher the melting and boiling point, the gaseous state is CH3Cl, the rest is liquid, and the carbon atom is conserved, so the amount of total matter is equal to the amount of methane.