Why are there 19 isomers?

First of all, the subject is not rigorous, and the isomers are afraid that the question is not rigorous, resulting in a sharp increase in species. There are hundreds of species of benzene itself. So the title was actually changed to:

There are several aromatic isomers of dimethylphenol, but generally people will default to containing benzene rings. Secondly, all isomers classified according to functional groups are: 5 alcohols, 5 ethers, 9 phenols (the subject can't deduce it again), counting the 19 substances given by the title, not counting the 18 species themselves.

Finally, I saw that someone said 6 kinds, he understood that only two methyl groups and one phenol hydroxyl group were inserted on the benzene ring, this subject can remember that 3 kinds of AAA, 6 kinds of AAB, and 10 kinds of ABC were inserted into the benzene ring, which would be easier to use in high school. Recently, I have been doing a special topic on isomers, and I hope to explain it clearly.

There are four scenarios.

1.(Benzyl formate), benzene ring substitution -Cl and -CH2-OOCH two groups, 3 kinds.

2.(methyl benzoate), benzene ring substitution -cooch3 and -cl two groups, 3 kinds.

3.(Phenyl formate), benzene ring substitution-ooch, -cl, -ch3 three groups, 10 species.

4.(phenyl acetate), benzene ring substituted -oocch3, -cl two groups, 3 kinds.

There are 19 isomers (esters, chlorine attached to the benzene ring).

Benzene ring substitution of -cooch3 and -cl groups, 3 species 3(Phenyl formate), benzene ring substituted -ooch, -cl, -ch3 three groups, 10 species 4(phenyl acetate), benzene ring substitution -oocch3, -cl two groups, 3 isomers (esters, chlorine attached to the benzene ring) a total of 19 kinds.

To know what isomerism is, we must first understand what is called isomerism, that is, the cavity of mountain compound cavity fiber has the same molecular formula, but the structure is different, so there is a difference in nature, this phenomenon is called isomerism, and the compounds with this phenomenon are called isomers. The phenomenon of isomerism is one of the reasons for the large variety and quantity of organic compounds.

If it's carbon chain isomerism, then we have a slip. Its writing rules are: the main chain is from long to short, the branch chain is from whole to scattered, the position is from the heart to the edge, the arrangement is from adjacent to the middle, and finally the hydrogen atom complements the four valence bonds of the carbon atom.

Of course, when writing Wu Fang, we must remember that the first carbon atom cannot be connected to the methyl group, the second carbon atom cannot be connected to the ethyl group, and so on. As for the position isomerism, you only need to pay attention to writing out all the carbon chain isomerism first, and then move the functional groups. Carbon chain isomerism and positional isomerism belong to tectonic isomerism, and there are stereoisomerism including configuration isomerism and conformational isomerism.

The phenomenon of isomerism is widely found in organic matter, and the knowledge of isomers also runs through the whole process of organic chemistry in middle school. Therefore, the analysis and judgment of isomers has become a major feature of organic chemistry. At present, isomers are mainly used as hot topics in college entrance examinations, and such test questions are an important means to test students' spatial imagination ability and structural writing ability.

Isomers.

The composition and molecular weight are exactly the same but the molecular structure is different Carbon chain isomerism: isomerism caused by the different order of connection of carbon atoms, such as ch3ch(ch3)ch3 and ch3ch2ch2ch3.

Functional group position isomerism: the isomerism phenomenon caused by the different positions of the large functional groups, such as: ch3ch2ch=ch2 and ch3ch=chch3.

Imitation and functional group heterogeneity: The isomerism caused by the difference of functional groups mainly includes:

Monoolefins and naphthenes: the general formula is CNH2N(N3).

Diolefins, monoalkynes and cyclomonoolefins: the general formula is CNH2N-2(N3).

Benzene and its cospinal bond system and polyene: the general formula is CNH2N-6(N6).

Saturated monools and saturated monoethers: the general formula is CNH2N+2O(N2).

Saturated monoaldehyde, saturated monoketo, enol: the general formula is CNH2NO(N3).

Saturated monocarboxylic acids, saturated monoesters, hydroxyaldehydes: the general formula is CNH2NO2(N2).

Phenol, aromatic alcohol, aromatic ether: the general formula is CNH2N-6O(N6).

glucose and fructose; Sucrose vs. maltose.

Amino acid. R-CH(NH2)-Cooh] and nitro compounds (R'-NO2). Example.

Write out the various isomers of C4H8O2 (requiring only one functional group in the molecule).

Analysis] According to the title, C4H8O2 should represent carboxylic acids and esters, where the type of carboxylic acid (i.e., C3H7Cooh) is equal to the type of C3H7, so there is.

The ester must meet the requirements of Rcoor (R can only be a hydrocarbon group, not a hydrogen atom), and R and R should contain a total of 3 carbon atoms, which may be:

c2—coo—c：

c—coo—c2：

h—coo—c3：

The physical and chemical properties are also different, ethanol and methyl ether.

Isomers are substances with the same molecular formula and different structures, heteroisomers are different substances with different molecular formulas, and allotropes are different substances composed of the same elements.

Isomer: An isomer is a compound with the same molecular formula but a different arrangement of atoms. To put it simply, the phenomenon that compounds have the same molecular formula but have different structures is called isomerism; Compounds with the same molecular formula but different structures are isomers of each other.

Many isomers have similar properties. In organic chemistry, isomers can be homogeneous substances (containing the same functional groups) or non-homogeneous substances (containing different functional groups).

Class. The essence of isomers produced by organic matter lies in the different order of atoms, which mainly refers to the following three situations in secondary school:

Carbon chain isomerism: isomerism caused by different attachment orders of carbon atoms, such as ch3ch(ch3)ch3 and ch3ch2ch2ch3.

Functional group position isomerism: the isomerism phenomenon caused by the different positions of functional mu, such as: ch3ch2ch=ch2 and ch3ch=chch3.

Heterogeneous isomerism of functional groups: The isomeric phenomena caused by the difference of functional groups mainly include:

Monoolefins and naphthenes: the general formula is CNH2N(N 1).

Diolefins, monoalkynes and cyclomonoolefins: the general formula is CNH2N-2(N3).

Benzene and its homologues and polyenes: the general formula is CNH2N-6(N6).

Saturated monool and saturated monoether: the general formula is CNH2N+2O(N2).

Saturated monoaldehyde, saturated monoketo, enol: the general formula is CNH2NO(N3).

Saturated monocarboxylic acids, saturated monoesters, hydroxyaldehydes: the general formula is CNH2NO2(N2).

Phenol, aromatic alcohol, aromatic ether: the general formula is CNH2N-6O(N6).

glucose and fructose; Sucrose vs. maltose.

Amino acid. R-CH(NH2)-COOH] with nitro compounds (R'-NO2).

What are the types of green bodies in the isomerism of the same section.

1. Writing of isomers.

1.Primary and secondary rules: When writing, we should pay attention to comprehensiveness and not repetition, and the specific rules are from long to short, branch chain from whole to scattered, position from heart to side, and arrangement from neighbor to intersection.

2.Ordering rules: Writing isomers should be done in an orderly manner, such as writing in the order of carbon chain isomerism, position isomerism, and functional group isomerism, or writing in the order of functional group isomerism, carbon chain isomerism, and position isomerism, no matter which method is written, omissions and rewriting must be prevented.

Carbon chain isomerism: The isomerism phenomenon caused by different carbon chains. For example, CH3CH2CH2CH2CH2CHO (valeraldehyde) and (CH3)2CHch2CH2CHo (2-methylbutyraldehyde).

Positional isomerism: The phenomenon of isomerism due to the different positions of functional groups on the carbon chain or carbon ring. For example, ch3ch2ch2ch2coh (1-butanol) ch3ch2ch(oh)ch3 (2-butanol).

Functional group isomerism: The phenomenon of isomerism due to different types of functional groups. There are mainly the following: olefins, naphthenes, diolefins, alkynes, saturated monool ethers, saturated monoaldehydes, saturated monocarboxylic acid esters, aromatic alcohols, aromatic ethers, phenols, nitro compounds, amino acids, glucose, fructose, sucrose, maltose.

For example, CH3CH2COOH (propionic acid) and CH3COOCH3 (methyl acetate) are isomers, but starch and cellulose are not isomers because N is unequal.

If the isomer with the molecular formula C5H12O is written, the writing idea is as follows:

1) Ignoring the oxygen atom in the molecular formula, write the isomer of C5H12, which has three carbon chain structures:

ch3―ch2―ch2―ch2―ch3（i）、

2) Considering the isomerism of the hydroxyl (alcohol) functional group, there are three isomers of the carbon chain structure formula (i).

ch3―ch2―ch2―ch2―ch2—oh、

3) Then considering the ether-based functional group, then the carbon chain structure formula (i) has two isomers:

ch3―o―ch2―ch2―ch2―ch3、ch3―ch2―o―ch2―ch2―ch3。

There are three isomers of the carbon chain structure formula (II): .

Carbon chain structure formula (iii) has only one structure: .

2. Methods for determining the number of isomers.

Motive method: If there are four types of butyl group, there are four isomers of butanol, valeraldehyde, valeric acid, etc.

Substitution: For example, dichlorobenzene (C6H4Cl2) has three isomers, and tetrachlorobenzene also has three isomers (H replaces Cl); For example, there is only one monochlorine substitute for CH4 and only one monochlorine substitute for neopentane [C(CH3)4].

Equivalent hydrogen method: The equivalent hydrogen method is an important method to judge the number of isomers, and its law is that hydrogen atoms on the same carbon atom are equivalent; Methyl hydrogen atoms on the same carbon atom are equivalent; The hydrogen atom on the carbon atom located in the symmetrical position is equivalent. There are several equivalent hydrogens and several halogenated compounds.

The five peaks are the positions of the five states that call for different hydrogen books.

For the reference of the sail ants burying the sedan sedan cherry blossoms.

Common heterogeneous types fall into two broad categories:

1. Structural isomerism:

Carbon chain isomerism: The phenomenon of isomerism due to the different shapes of carbon chains in a molecule. Such as n-butane and isobutane.

Positional isomerism: Isomerism due to the different positions of substituents or functional groups on the carbon chain or on the carbon ring.

2. Stereoisomerism: the structure is similar, but the structure is different due to small deviations. Specifically, it can be divided into configuration isomerism and conformational isomerism.

Two or more compounds with the same chemical formula, but different structures and properties, are called isomers of each other, and this phenomenon is called "isomerism".

Isomers in organic matter are divided into two categories: tectonic isomerism and stereoisomerism.

Tectonic isomerism is further divided into (carbon) chain isomerism, positional isomerism and functional group isomerism (heteroisomerism).

Stereoisomerism is further divided into conformational and configuration isomerism, and configuration isomerism is also divided into cis-trans isomerism and optical rotation isomerism (also known as enantiosterism).

What are the types of isomers?

Detection of aldehyde groups Isomers of aldehydes.

What are the types of green bodies in the isomerism of the same section.

The isomers are the same as the molecular formula;

Isomerism is a difference in molecular structure.

For example, the same molecular formula C6H14 has a different structure