The occurrence conditions of chemical organic reactions in high schools

Elimination reaction:

Ethanol is eliminated and dehydrated under the action of concentrated sulfuric acid to form a double bond to become ethylene.

This kind of alcohol dehydroxyl group and hydrogen (water) elimination reaction is reacted under the heating condition of concentrated sulfuric acid to form a double bond.

Other elimination reactions, such as the elimination of halogenated hydrocarbons, are all in.

NaOH ethanol solution is heated to remove halogen atoms and hydrogen atoms.

Elimination reaction conditions: Hydroxyl carbon must contain H atoms on adjacent carbon atoms.

Substitution reactions: Substitution reactions in general occur under light conditions.

Substitution of alcohols, such as the reaction of ethanol with concentrated hydrohalic acid, the hydroxyl group is substituted. Halogenated hydrocarbons and water are generated.

In addition, the esterification reaction also belongs to the substitution reaction type, which is said together

The reaction occurs under the heating condition of concentrated sulfuric acid, and remember that water is generated.

Addition reactions: alkynes and bromine water (carbon tetrachloride of bromine. liquid bromine) can be carried out directly, without catalysis.

Benzene and benzene congeners are only the same as liquid bromine, remember not bromine water. It is added under the catalytic conditions of iron bromide (in fact, after adding iron, it is automatically oxidized by bromine to iron bromide).

Oxidation reaction: ethanol is oxidized with oxygen heating under the catalysis of Cu (CuO) and Ag to form acetaldehyde and water (the reaction condition is that the hydroxyl carbon atom must be connected to the H atom) (it is also possible to directly generate acetic acid in one step, depending on the problem conditions).

Acetaldehyde is heated with oxygen under the action of a catalyst to oxidize to form acetic acid. or acetaldehyde undergoes a silver mirror reaction, remember that it must occur under alkaline environmental conditions, heating reaction.

Hydrolysis reaction: Generally, all esters (including oils and fats) can be hydrolyzed by adding dilute sulfuric acid, and hydrolyzed into acids and alcohols by adding NaOH for heating.

The hydrolysis of halogenated hydrocarbons is a heating reaction in an aqueous solution of NaOH to produce alcohols and halides.

Conditions for hydrolysis: 1. The salt must be dissolved in water, 2. There must be a weak acid group or a weak alkali cation in the salt (there is a weak hydrolysis, no weak is not hydrolyzed, the weaker the more hydrolyzed).

Of course, the above is a general situation, there is no absolute, and various reactions should be analyzed in detail.

Question 1: What are the required conditions in the high school organic chemical reaction alkane substitution reaction: brominated by photobenzene: iron bromide.

Nitration of benzene: concentrated sulfuric acid 50-60°C

Hydrolysis of halogenated hydrocarbons: Aqueous solution of NaOH heating.

Halogenated hydrocarbons are eliminated: NaOH alcohol solution is heated.

Ethanol elimination: concentrated sulfuric acid 170°C

Ethanol intermolecular dehydration: concentrated sulfuric acid 140°C

Ethanol catalytic oxidation: Cu ag heating.

Esterification reaction: concentrated sulfuric acid is reversible when heated with sulfuric acid.

Hydrolysis of lipids: acidic, alkaline.

Question 2: Write the reaction conditions in the high school organic chemistry exam.

In organic synthesis, there must be correct writing reaction conditions; In organic inference, there are generally conditions in the question, and it is only necessary to copy it over.

Question 3: Summary of high school organic chemical reaction conditions, such as what reactions are under light The main light reactions that need to be mastered in high school are: plant photosynthesis, the combination of hydrogen and chlorine, alkane halogenation, and the photodecomposition of silver bromide and silver iodide.

R-CHO+2[AG(NH3)2]OH (water bath plus sock bridge fever) R-CoonH4+2AG+3NH3 +H2O

On the inner wall is a layer of metal wax scattered silver that is as bright as a mirror.

RCHO+2Cu(OH)2== RCOOH+Cu2O(precipitate) +2H2O

The water bath heats the red precipitate.

fecl3 + 6 c6h5oh ==h3[fe(c6h5o)6] +3 hcl

Chromogenic reaction of phenol with ferric chloride, purple.

c6h6oh + 3 br2 =c6h3ohbr3 ↓ 3hbr

White precipitate. C6H6 + Hno3 (concentrated) == concentrated sulfuric acid, heating === C6H5-NO2 + H2O

Benzene + 3H2 = (nickel Ni as catalyst, heated) = cyclohexane.

The substitution of benzene and bromine reacts with iron as a catalyst.

Problem 1: High School Chemistry Organic Reactions The first reaction is heated. The general preparation method is to heat solid NABR, concentrated sulfuric acid, and ethanol together.

Solid sodium bromide and concentrated sulfuric acid are reacted to produce hydrogen bromide and sodium bisulfate. Hydrogen bromide reacts with ethanol to form halogenated hydrocarbons.

The second reaction is the coheating of the aqueous solution of NaOH.

When writing the equation, you can write the reaction product HBR with water, or it can be sodium bromide, which is actually the product of the reaction between hydrogen bromide and sodium hydroxide.

Question 2: High School Chemistry Organic Reactions B

Question 3: Why do high school chemical organic reactions have certain reaction conditions Chemical reactions are more complex, generally speaking, they are carried out by the main reaction accompanied by side reactions, high school studies generally only study the main reaction under certain conditions, the reaction conditions are to decide which reaction is the main reaction, and the catalyst is to reduce the conditions of the reaction (the energy required for chemical bond breakage), or speed up the reaction.

For example, the reaction of ethanol acetic acid to produce esters is reversible, and it is possible to oxidize ethanol and decompose esters, etc., and the condition is that the reaction to generate esters is used as the main reaction and the progress of other reactions is inhibited.

Question 4: Find several typical reactions in the organic part of high school chemistry substitution reactions.

1) The reaction of methane and chlorine under light conditions.

2) Reaction of benzene and liquid bromine catalyzed by iron powder.

3) The reaction of benzene with concentrated nitric acid catalyzed by concentrated sulfuric acid.

4) Esterification reaction of ethanol and acetic acid.

5) Hydrolysis of ethyl bromide.

Addition reaction.

There are many laws, but there is a common essence in them, and it is better to grasp this essence than to memorize them.

Strong acids make weak acids because the ionization degree of hydrogen ions is different, the binding force of acid radicals and hydrogen ions is different, who attracts hydrogen more strongly, and hydrogen ions with whom;

Difficult to volatilize and easy to volatile: for example, sulfuric acid to hydrochloric acid is because hydrochloric acid can be separated from the system of sulfuric acid, the reaction is easy to carry out, and the reaction tendency of hydrochloric acid is greater;

The formation of acid salts by multiple positive salts and multiple weak acids is also due to the binding force of acid ions and hydrogen ions.

To see whether a reaction can be carried out, it depends on who has more binding power with whom and whether there is a tendency to react. There is a theory of acid-base protons that you can look at. There is also an ionic reaction that can occur not only depends on the difficulty of ion binding, but also the specific situation of the system, such as refractory volatile and volatile.

Seven Hidden Laws:

1. Replace it, 1 1 1 1 1

H on alkanes can undergo photohalogenation with halogen elements to generate halogenated hydrocarbons and hydrogen halides.

The h on the benzene trouser ring can be brominated with liquid bromine catalyzed by iron to produce bromobenzene and hydrogen bromide.

The h on the benzene ring can also be combined with nitric acid.

Nitrification occurs.

The h on the benzene ring can also be combined with concentrated sulfuric acid.

Sulfonation occurs.

Hydrolysis of halogenated hydrocarbons to obtain alcohols.

Alcohols and hydrohalic acids are reacted to obtain halogenated hydrocarbons.

Carboxylic acids and alcohols undergo esterification reactions catalyzed by concentrated sulfuric acid to form esters and water.

Hydrolysis of esters.

2. Addition 1 1 1, generally adding small molecules H2, X2, Hx, H2O carbon-carbon double bonds, and carbon-carbon triple bonds can be added.

Benzene ring plus H2, X2

Carbonyl in aldehydes, ketones.

H2 and HCN can be added

3. Eliminate 1 1 1, the small molecules that are generally eliminated are H2O, Hx, and some alcohols can be eliminated to obtain the corresponding olefins.

Some halogenated hydrocarbons can be eliminated to obtain the corresponding olefins.

4. Oxidation There are two kinds of oxidation: oxygen oxidation and dehydration.

The combustion of organic matter is completely oxidized.

Alcohols are catalyzed to oxidize to form aldehydes or ketones, which belong to dehydration.

Aldehydes are oxidized to acids, which belong to oxygenation.

The side-chain alkyl group of the benzene ring is covered by potassium permanganate.

The acidic solution is oxidized to benzoic acid (alpha carbon must have H atoms on it before it can be oxidized), and the carbon-carbon double bond and carbon-carbon triple bond are oxidized by the potassium permanganate acidic solution.

5. Reduction The addition reaction with hydrogen is also a reduction reaction.

In addition, nitrobenzene reacts with iron and hydrochloric acid to form aniline, which is also a reduction reaction.

6. Polyaddition Polymerization reaction on the basis of addition.

It is generally the nature of a carbon-carbon double bond.

The polyaddition reaction of olefins is carried to form polyethylene and polyvinyl chloride.

polystyrene, etc.

The polyaddition reaction of diolefins produces natural rubber, butadiene rubber, neoprene rubber, styrene-butadiene rubber, etc.

7. Polycondensation condensation polymerization reaction, in addition to the generation of polymers, also obtain small molecule products, generally water.

Phenol. Polycondensation with formaldehyde to form phenolic resin.

Adipic acid. Polycondensation with ethylene glycol into polyester (both diacids and diols can react similarly) amino acids. Polycondensation into a fetus, and further polycondensation into proteins.