What organic matter can undergo the elimination reaction?

Alcohols. Halogenated hydrocarbons can undergo a dissipation reaction.

It is generally required that there is at least one hydrogen atom on the ortho-carbon atom of the functional group, that is, beta-hydrogen.

Alcohols and halogenated hydrocarbons can be eliminated.

But only if there is hydrogen on the carbon atom next door to alcohols and halogenated hydrocarbons!

Alcohols and halogenated hydrocarbons can be eliminated.

The reaction in which an organic compound removes one or several small molecules (such as water, hydrogen halide, etc.) from a molecule under appropriate conditions to form an unsaturated (carbon-carbon double or triple bond) compound is called an elimination reaction.

The key point is that the unsaturation must be increased!

Alcohols and halogenated hydrocarbons can be eliminated. In the alcohol molecule, the carbon atom with a hydroxyl group (-OH) must have an adjacent carbon atom and a hydrogen atom attached to the adjacent carbon atom before the elimination reaction can occur.

Intramolecular dehydration produces olefins, which are essentially elimination reactions. The ability to generate stable alkenes (the more alkyl groups in the carbon atom chains of the alkene double bond, the more stable it is), which is conducive to the elimination of the reaction.

Reactivity of alcohol: 3° alcohol> 2 ° alcohol, > 1 ° alcohol.

The intramolecular dehydration of alcohols is due to the electron-withdrawing induction effect of the hydroxyl group, which is produced by the easy elimination of H, and when there are many different H, the easiest to eliminate is H with less hydrogen, because stable olefins can be generated. This rule is called the saytzeff rule.

Take ethyl bromide as an example (either NaOH or KOH).

CH3CH2BR + NAOH ==> CH2=CH2 +NABR + H2O (Conditions: Alcohol solution of NaOH, heated).

Note: 1. The elimination reaction is a decomposition reaction. The elimination reaction is a reaction in which one molecule becomes two molecules, and is therefore a decomposition reaction.

2. The elimination reaction is an intramolecular reaction, and the reaction between molecules to form small molecules is not an elimination reaction.

3. The result of the elimination reaction is to increase the degree of unsaturation of organic matter.

4. The elimination reaction and addition reaction are reversible reactions, but they are not reversible reactions due to different reaction conditions.

1. Carbon-carbon double bond: oxidation, and polymerization reaction.

Reaction principle: carbon double bond breaking.

Reaction conditions: addition and water are high-temperature and high-pressure catalysts, and bromine and hydrogen bromide are not.

2. *c c bond: similar to carbon-carbon double bond.

3. *Halogenated hydrocarbons: functional groups, halogen atoms.

A "hydrolysis reaction" takes place in a solution of alkali to produce alcohol.

CH3CH2BR+ H2O CH3CH2OH + HBR reaction principle: substitution, OH substitution of halogen atoms in water.

Reaction conditions: aqueous solution of sodium hydroxide, heating.

4. The "elimination reaction" occurs in the alkaline alcohol solution to obtain unsaturated hydrocarbons.

Reaction principle: A reaction in which a small molecule (Hx) is removed from an organic molecule to generate an unsaturated tenant compound (containing double or triple bonds).

Reaction conditions: alcohol solution of sodium hydroxide, heating.

5. *Alcohol: functional group, alcohol hydroxyl group.

It can react with sodium to produce hydrogen.

Reaction conditions: None.

6. Unsaturated hydrocarbons can be eliminated and obtained.

Reaction principle: The carbon atoms directly connected to the hydroxyl group are eliminated to form water, and the karyotype cannot be eliminated if there are no hydrogen atoms.

Reaction conditions: concentrated sulfuric acid, high temperature.

It can be esterified with carboxylic acid.

Reaction principle: acid dehydroxyl group, alcohol dehydrogenation, belongs to the elimination reaction.

Reaction conditions: concentrated sulfuric acid, heating.

It can be catalytically oxidized to aldehydes (primary alcohols are oxidized to aldehydes, secondary alcohols are oxidized to ketones, and tertiary alcohols cannot be catalytically oxidized).

Conditions for the elimination reaction to occur: In the alcohol molecule, the carbon atom with the hydroxyl group (-OH) must have adjacent carbon atoms and the adjacent carbon atom must also have hydrogen atoms attached to the adjacent carbon atom before the elimination reaction can occur and form an unsaturated bond. The law of elimination reactions:

Alcohol containing one carbon atom (e.g., ch3oh) has no adjacent carbon atoms, so the elimination reaction cannot occur; Alcohol without hydrogen atoms on the adjacent carbon atoms in the volcanic field and adjacent to the hydroxyl group cannot undergo the elimination ridge reaction.

The condition of the substitution reaction is that there must be a substitution reaction (such as halogen elements) and a substitute (hydrogen atom, etc.) inorganic matter without substitution reaction, and there is a similar displacement reaction.

The basic types of organic chemical reactions mainly include substitution reactions, addition reactions, polymerization reactions, etc. 1.Substitution reactions.

The reaction in which an atom or cluster of atoms in an organic compound molecule is replaced by other atoms or atomic leuces is called a substitution reaction. 3.Polymerization reactions.

The reaction in which a low molecule is combined into a high molecule (or macromolecule) is called a polymerization reaction. 4.Removal reaction.

The reaction of removing a simple molecule from an organic compound molecule and generating unsaturated to make a quiet compound is called an elimination reaction. 5.Rearrangement reactions.

Due to the poor stability of organic compounds, under the influence of external factors such as normal temperature and atmospheric pressure waxing or other reagents, heating and other external factors, the transfer of some groups in the molecule or the change of the carbon atom skeleton in the molecule is called rearrangement reaction.

Pure lead article

Ethanol is eliminated and reacted into ethylene and water.

Halogenated hydrocarbons are formed into olefins in an alcohol solution of NaOH.

CH3CH2-X+NaOH = CH3CH2OH+NaX+H2O alcohols form olefins under the condition of sulfuric acid.

h2so4ch3ch2oh*****c2h4+h2o

Some halogenated hydrocarbons can undergo a dissipation reaction, which requires that the halogen atoms are connected to the adjacent carbon atoms of the hydrogen atoms.

The reaction conditions are sodium hydroxide alcohol solution, heated.

Some alcohols can undergo a dissipation reaction, which requires a hydrogen atom on the adjacent carbon atom of the hydroxyl group.

The reaction conditions are concentrated sulfuric acid, heated. For example, ethanol is concentrated sulfuric acid, 170 degrees Celsius, and the temperature of other alcohols is different.

A The elimination reaction cannot occur, and there must be more than two C atoms.

b；The elimination reaction occurs. CH3CH=CH2

C: Elimination reaction occurs CH3CH=C(CH3)2CH3CH2-C=CH2

CH3D: No elimination reaction can take place, and the adjacent C atom does not have a hydrogen atom.

cccccccccccccccc

A cannot be eliminated, and the elimination must be the halogen atom on -c and the h atom on -c.

Although b can be eliminated, it is symmetrical because of the halogenated hydrocarbons, that is to say, whether the h on the left or the h on the right is the same product.

There is no h on -c in the positive solution of c, which cannot be eliminated.

There are halogen groups or hydroxyl groups commonly found in high school selection, which can be eliminated, but there is a requirement that there must be hydrogen on the ortho-carbon containing these groups in order to eliminate hydrogen halide or water molecules. A, D are excluded, and B eliminates only one product, CH3CH=CH2

HBR can be eliminated on both the left and right sides of CBR and different products CH3CH=C(CH3)2,

ch3ch2-c=ch2

ch3

Elimination reaction: A reaction in which alcohols or halogenated hydrocarbons remove small molecules (water or hydrogen halides) to form unsaturated double or triple bonds.

To remove the conditions for the reaction to occur, there must be a hydroxyl or halogen atom, and there must be at least one hydrogen atom on the ortho-carbon of c attached to the hydroxyl or halide atom. It can be understood by referring to the book, the elimination reaction of ethanol.

A reaction in which two small groups are lost on two adjacent carbon atoms within an organic molecule, forming unsaturated bonds. For example, in an ethanol molecule, one carbon atom loses a hydroxyl group, and another carbon atom loses a hydrogen atom, and the two combine to form water, and ethanol becomes ethylene.