Is the reaction between ethylene and bromine an addition reaction or a substitution reaction?

It depends on the reaction conditions:

1. If ethylene is directly introduced into bromine water or liquid bromine at room temperature, an addition reaction occurs to generate 1,2-dibromoethane, which is the result of the breaking of one of the carbon-carbon double bonds and the addition of two bromine atoms.

2. If ethylene and bromine steam are about 500 degrees Celsius and there is a catalyst, a substitution reaction occurs, and the bromine atom will replace a hydrogen atom to generate ethylene bromide and hydrogen bromide, which belongs to the substitution reaction.

To determine which type of reaction it belongs to, you can use the previous friend's, because after the addition reaction, no bromine ions exist, and after the substitution reaction, because of the formation of hydrogen bromide, it can be dissolved in water and tested with silver nitrate solution.

It's an addition reaction.

Extract a small amount of the reaction liquid in a clean test tube, and then add a few drops of silver nitrate solution, if there is a yellowish precipitate formed, it means that it is a substitution reaction.

Otherwise, it is a substitution reaction.

Easy to replace at high temperatures.

It is a bonus at room temperature.

We did a lot of questions when we were preparing for the exam.

Some of the questions give high temperature conditions and explain that they are replaced.

But at room temperature, it's a bonus.

If this is the case.

You can add silver nitrate solution after phase reaction.

See if there is a noticeable yellow precipitate.

There will be no bonuses.

Because. BR all became functional groups.

If it is bromine water.

Then this method will not work.

Because bromine, which is soluble in water, also ionizes bromine ions.

to silver ions. Precipitation occurs.

What is the chemical reaction of ethylene with bromine water? Let's take a look.

Ethylene can react with bromine water and liquid bromine。The elemental reaction of ethylene and bromine is an addition reaction of olefins.

The addition reaction takes place in substances that have double or triple bonds (unsaturated bonds). After the reaction progresses, the heavy bond opens and the atoms at each end of the original heavy bond are connected to a new group. The addition reaction is generally the reaction of two molecules to form one molecule, which is equivalent to the chemical reaction of inorganic chemistry.

Ethylene is connected by a double bond between two carbon atoms, and an addition reaction can occur.

The essence of bromine: iodine and bromine are easily decomposed in halogen elements, and bromine is the only non-metallic element that is liquid and easily volatile, so it should be isolated with water.

In fact, water reacts with bromine to form hydrogen bromide and hypobromic acid, which is very unstable and easily decomposes when seen in light. In fact, the preservation of the brown bottle is to protect the hypobromoic acid, and from the perspective of chemical balance, the protection of the hypobromide indirectly protects the liquid bromide, slowing down the further consumption of liquid bromide.

Because liquid bromide br2 is not an absolute non-polar molecule, the molecule itself will be polarized, producing δ+br δ-br, which reacts with ethylene as an electrophilic addition, and the δ+br end first attacks the -electron of the c=c double bond. As for why bromine water is used? Because water is a polar solvent, it is conducive to inducing the polarization of BR2 and increasing the reaction speed, which is the polar solvation to promote the reaction.

On the other hand, bromine water dilutes liquid bromine, reducing the concentration of bromine and also reducing the reaction rate, otherwise this addition reaction will get out of control and lead to side reactions, which is also a factor to consider in industrial laboratories. Because the concentration of liquid bromine is too large, the reaction is prone to get out of control (especially in large quantities, and the effect of heat transfer needs to be paid attention to), so liquid bromine needs to be diluted. However, in teaching textbooks, bromine water is generally mentioned more, but in the actual reaction with vinyl plus bromine, bromine water is not always used, and liquid bromine is often diluted in hexane or ether and added dropwise to the reaction.

Some reactions cannot be in contact with water, and it is more prudent to use bromine water to do the addition reaction of bromine.

Not an addition reaction, but a substitution reaction.

The difference between addition reaction and substitution reaction: addition reaction is an organic chemical reaction, which mainly occurs in substances with double or triple bonds (unsaturated bonds), and the reaction process is mainly double bonds to single bonds, saturation changes, and there is only one product after the reaction. The substitution reaction mainly occurs in the carbon-carbon single bond, the saturation is unchanged, and the products are still two after the reaction.

Addition and redox reactions are two different types of reactions in organic reactions and cannot be compared together.

Different from the definition of redox reaction in inorganic chemistry, the definition of reduction reaction in organic chemistry is the deoxygenation or hydrogenation of organic compounds, rather than the transfer or bias of electron pairs in inorganic chemistry, because in organic compounds, the carbon elements are all -4 valence or +4 valence, and there is no change.

Addition reaction is defined as the reaction in which unsaturated carbon atoms in an organic molecule directly combine with other atoms or groups of atoms to form a new substance.

There will certainly be a transfer of electron pairs (breaking of unsaturated bonds and the formation of new bonds) in addition reactions, and in the definition of inorganic it must be a redox reaction.

For example, the addition of ethylene and hydrogen to produce ethane is both an addition reaction and a reduction reaction (because the valency of hydrogen in hydrogen increases to +1 valence), but the addition of ethylene and water to ethanol is only an addition reaction because the valency does not change.

It does not belong to the substitution reaction, that is, the hydrogen atom on a carbon atom of organic matter is replaced by a bromine atom, which can be saturated or unsaturated. The addition reaction must be a reaction in which the unsaturated hydrocarbon is carried out.

In organic chemistry, there are several kinds of additions that can be added with bromine, not necessarily an addition reaction.

Free radical reactions, such as methane and bromine in light exposure, are a free radical substitution.

In addition reaction, the carbon tetrachloride solution of bromine and alkenes or alkynes are called before the addition of fibers.

The HIV repentance of carboxylic acids should be a substitution reaction of bromine.

The reaction of the introduction of bromine on the benzene ring is a nucleophilic substitution reaction.

The presence of aldehydes and ketones in the introduction of bromine in position is a nucleophilic substitution reaction.

The allyl position of the olefin introduced into bromine is a free radical substitution.

The bromoform reaction of methyl ketone derivatives is nucleophilic substitution.

It is not a bonus anti-limb response. "Dai" means "to replace" and "to replace", and it is obvious that there is no Xi Zheng being replaced when "adding to the Ode to Hunger", but "adding".

The brominated reaction does not belong to the addition reaction, it belongs to the substitution reaction.

Bromine water also has some oxidizing properties. Some inorganics can be oxidized by bromine water. Organic bromine water is prone to electrophilic reactions, including electrophilic addition and electrophilic substitution.

Ethylene undergoes an addition reaction with bromine to form dibromoethane.

Introducing ethylene into bromine water will discolor the bromine water.

The introduction of ethylene into the carbon tetrachloride solution of bromine will discolor the carbon tetrachloride solution of bromine.

Ethylene reacts with bromine water to form dibromoethane.

The chemical equation for the reaction is:

ch2=ch2 + br2 → ch2brch2br .

Experimental phenomenon: Bleaching of bromine water.

What is the chemical reaction of ethylene with bromine water? Let's take a look.

The reaction of ethylene and bromine water is an addition reaction.

Ethylene: It is the basic chemical raw material of synthetic fibers, synthetic rubber, synthetic plastics (polyethylene and polyvinyl chloride), synthetic ethanol (alcohol), and is also used in the manufacture of vinyl chloride, styrene, ethylene oxide, acetic acid, acetaldehyde, ethanol and explosives, etc., and can also be used as a ripening agent for fruits and vegetables, and is a proven plant hormone.

Bromine water: The mixture of elemental matter and water is called bromine water. Bromine is slightly soluble in water, and more than 80% of bromine will react with water to form hydrobromic acid and hypobromic acid, but there will still be a small amount of bromine dissolved in water, so bromine water is orange-yellow.

Addition reaction: Addition reaction is an organic chemical reaction that occurs in substances with double or triple bonds (unsaturated bonds). The reaction in which two or more molecules interact with each other to form an addition product is called an addition reaction.

Addition reactions can be ionic, radical, and synergistic.

The reaction of ethylene and water is an addition reaction. The addition reaction is in which two atoms in the reactant molecule that are bound by heavy bonds or at the end of the co-unsaturated system are combined with the groups or atoms provided by the reagent in O bonds respectively to obtain a saturated or relatively saturated addition product.

Difference Between Substitution Reaction and Addition Reaction:

The nature of the reaction is different:

The addition reaction is a characteristic reaction of the class of unsaturated compounds. Substitution reaction: It is a reaction in which any atom or cluster of atoms in a compound or organic molecule is replaced by other atoms or clusters of atoms of the same type in the reagent.

Addition reactionsAddition reactions can be divided into nucleophilic addition reactions, electrophilic addition reactions, free radical additions, and cycloadditions.

The addition reaction can also be divided into cis addition and trans addition. Substitution reactions: Substitution reactions can be divided into three categories: nucleophilic substitution, electrophilic substitution, and homolysis substitution.

Substitution of reaction judgment method:

There must not be elemental in the reactant, and there must be no elemental in the product; Whether the reaction can be carried out is affected by external conditions such as temperature, light, catalyst, etc.; The reactions are gradual, and many reactions are reversible; Halogen ions or other groups replace the original (chloride ions replace the hydrogen off-the-ruler Haruko).

Addition reaction judgment method:

The reaction in which two or more molecules interact with each other to form an addition product is called an addition reaction. Addition reactions can be ionic, radical, and synergistic. The ionic addition reaction is caused by chemical bond resistance to heterocleavage, which is divided into electrophilic addition and nucleophilic addition.

After the addition reaction, the heavy bond opens, and the atoms at each end of the original heavy bond are connected to a new group.