Why olefins and water can be added under acidic conditions

Protons are electrophilic, first of all, protons attack double bonds (double bonds have a high density of electron clouds) to form C+, and then oxygen in water attacks C+ ions to form alcohols and protons, and the reaction is equivalent to water attacking alkenes.

Catalyst, heating.

1. After the addition reaction is carried out, the heavy bond is opened, and the atoms at both ends of the original heavy bond are connected to a new group.

2. The addition reaction is generally a two-molecule reaction to form a molecule, which is equivalent to the chemical reaction of inorganic chemistry. According to the mechanism, addition reactions can be divided into nucleophilic addition reactions, electrophilic addition reactions, free radical additions, and cycloadditions.

ch2=ch2 + h2o – catalyst heating and pressurization – >ch3ch2oh ch2=ch2 + br2 – ch2brch2br ch2=ch2 + hcl – catalyst heating – >ch3ch2cl ch2=ch2 + h2 – catalyst heating – >ch3ch3 adding water, pressurized bromine is added, no conditions required other, heating catalyst, what is the catalyst, no need to write . Hydrogenation.

Use different catalysts.

Regioselectivity refers to a reaction in which only one product is generated, or predominantly, when the orientation of the reaction is likely to produce several isomers.

A stereoselective reaction is one in which several stereoisomers (e.g., cis-adduct and trans-adduct) may be produced in a reaction that preferentially (but not 100%) gives one of the stereoisomers (or a pair of enantiomers.

A highly stereoselective reaction is called a stereo-specific reaction, which refers to the stereochemically differentiated reactants that give the stereochemically related differential products.

The addition of bromine to CC double bond is a stereoselective reaction.

The epoxidation reaction between olefins and peroxy acid is a highly stereoselective reaction, that is, a stereospecificity reaction.

Looking specifically at the organic chemistry book, the fischer projection is not easy to draw here, so the specific reaction mechanism can only be read by yourself.

The addition of olefins and water belongs to the () wide dress.

a.Electrophilic bonus.

b.Free empty comma base bonus.

c.Nucleophilic bonus.

d.It is not certain that the loss of care is determined.

Correct Answer: Electrophilic bonus.

Summary. In general, the more active an olefin is, the more easily its double bonds can be added to or react with other molecules. The activity of an olefin has a great relationship with its molecular structure, and the following are some common methods to determine the activity level:

1.Number of carbon-carbon double bonds: the higher the number of double bonds, the higher the activity; 2.

Double bond site: If the double bond is located at the end of the molecule, its activity is higher than the internal position; 3.Double bond structure:

The multi-conjugated double-bond structure will be more active than the independent double-bond structure; 4.Double bond type: olefins have higher activity than alkanes, and aromatic hydrocarbons have higher activity than olefins.

It should be noted that the activity of olefins is not only related to itself, but also related to the reaction system, reaction conditions and other factors, so in addition to the molecular structure, the experimental results also need to be used as a basis for supplementing the judgment of the activity.

propylene and 3,3,3-trichloropropene.

The following pairs of olefins and sulfuric acid are added, and the activity of the former is higher than that of the latter

aPropylene and 2-butene.

B1-pentene and 2-methyl-1-butene.

C2-butene and 2-methylpropylene.

dThe following additives to olefins and sulfuric acid, the activity of the former is higher than that of the latter:

propylene and 3,3,3-trichloropropene.

How do you look at the level of activity?

2-Butene and 2-Methpropene.

C1-pentene and 2-methyl-1-butene.

b propylene and 2-butene.

aThe following additives to olefins and sulfuric acid, the activity of the former is higher than that of the latter:

propylene and 3,3,3-trichloropropene.

D2-butene and 2-metholpropene.

C1-pentene and 2-methyl-1-butene.

b propylene and 2-butene.

aThe following additives to olefins and sulfuric acid, the activity of the former is higher than that of the latter:

propylene and 3,3,3-trichloropropene.

D2-butene and 2-metholpropene.

C1-pentene and 2-methyl-1-butene.

b propylene and 2-butene.

aThe following additives to olefins and sulfuric acid, the activity of the former is higher than that of the latter:

Acidified water is a mixture, usually consisting of a mixture of sulfuric acid and water. Acidified water is capable of converting olefins into aldehydes and ketones. For example, formaldehyde and acetone can be obtained by mixing methane, an olefin, with acidified water.

This is due to the fact that the sulfuric acid solution in the acidified water can react with the olefins in the methane to convert the olefins into aldehydes and ketones. Acidified water can also convert other olefins into aldehydes and ketones. However, the specific type and amount of compounds converted depends on the structure and conditions of the olefin, such as temperature, time, and concentration.

This is the mechanism of the olefin hydration reaction. If you don't learn the chemistry competition in high school, you can ignore it.

Finally, protons are exchanged, and because roh2(+) is more acidic than h3o(+), proton exchange will occur.