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Difference between isopropyl and isobutyl
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Lekha Shri
Difference between isopropyl and isobutyl
The IUPAC Organic Chemistry Nomenclature does not explicitly define the "iso-" prefix meaning, as it is not used in the systematic naming. However, it is mentioned on several places when listing acceptable semi-systematic names. In the section A-2 (1979 Blue book, some also in 1993 Recommendations, section R-9.1, table 19a) those are (not mentioning neo- compounds)
isobutane (CH3)2CH−CH3
isopentane (CH3)2CH−CH2−CH3
isohexane (CH3)2CH−CH2−CH2−CH3
And in the section A-2.25 (some also in R-9.1, table 19b), where it lists acceptable "isoalkyl group" names:
isopropyl (CH3)2CH−
isobutyl (CH3)2CH−CH2−
isopentyl (CH3)2CH−CH2−CH2−
isohexyl (CH3)2CH−CH2−CH2−CH2−
Some related isomeric alkyls mentioned in this section are
sec-butyl CH3−CH2−CH(CH3)−
tert-butyl CH3−CH(CH3)2−
tert-pentyl CH3−CH2−CH(CH3)2−
There are also some other, unsaturated "isoalkyl" group names mentioned:
isopropenyl CH2=C(CH3)−
isopropylidene (CH3)2C=
From the above we can induce that "iso-" prefix, when related to alkanes or alkyl groups, it means the simplest (n-)alkane/alkyl isomer branched at the end of the carbon chain.
Isopropyl happens to be secondary (sec) alkyl (there's lack of carbon atoms to create primary alkyl isomeric to the n-propyl), all higher isoalkyls are primary (no branching at the alkyl "attachment").
The IUPAC Organic Chemistry Nomenclature does not explicitly define the "iso-" prefix meaning, as it is not used in the systematic naming. However, it is mentioned on several places when listing acceptable semi-systematic names. In the section A-2 (1979 Blue book, some also in 1993 Recommendations, section R-9.1, table 19a) those are (not mentioning neo- compounds)
isobutane (CH3)2CH−CH3
isopentane (CH3)2CH−CH2−CH3
isohexane (CH3)2CH−CH2−CH2−CH3
And in the section A-2.25 (some also in R-9.1, table 19b), where it lists acceptable "isoalkyl group" names:
isopropyl (CH3)2CH−
isobutyl (CH3)2CH−CH2−
isopentyl (CH3)2CH−CH2−CH2−
isohexyl (CH3)2CH−CH2−CH2−CH2−
Some related isomeric alkyls mentioned in this section are
sec-butyl CH3−CH2−CH(CH3)−
tert-butyl CH3−CH(CH3)2−
tert-pentyl CH3−CH2−CH(CH3)2−
There are also some other, unsaturated "isoalkyl" group names mentioned:
isopropenyl CH2=C(CH3)−
isopropylidene (CH3)2C=
From the above we can induce that "iso-" prefix, when related to alkanes or alkyl groups, it means the simplest (n-)alkane/alkyl isomer branched at the end of the carbon chain.
Isopropyl happens to be secondary (sec) alkyl (there's lack of carbon atoms to create primary alkyl isomeric to the n-propyl), all higher isoalkyls are primary (no branching at the alkyl "attachment").
The IUPAC Organic Chemistry Nomenclature does not explicitly define the "iso-" prefix meaning, as it is not used in the systematic naming. However, it is mentioned on several places when listing acceptable semi-systematic names. In the section A-2 (1979 Blue book, some also in 1993 Recommendations, section R-9.1, table 19a) those are (not mentioning neo- compounds)
And in the section A-2.25 (some also in R-9.1, table 19b), where it lists acceptable "isoalkyl group" names:
Some related isomeric alkyls mentioned in this section are
There are also some other, unsaturated "isoalkyl" group names mentioned:
From the above we can induce that "iso-" prefix, when related to alkanes or alkyl groups, it means the simplest (n-)alkane/alkyl isomer branched at the end of the carbon chain.
Isopropyl happens to be secondary (sec) alkyl (there's lack of carbon atoms to create primary alkyl isomeric to the n-propyl), all higher isoalkyls are primary (no branching at the alkyl "attachment").
The IUPAC Organic Chemistry Nomenclature does not explicitly define the "iso-" prefix meaning, as it is not used in the systematic naming. However, it is mentioned on several places when listing acceptable semi-systematic names. In the section A-2 (1979 Blue book, some also in 1993 Recommendations, section R-9.1, table 19a) those are (not mentioning neo- compounds)
And in the section A-2.25 (some also in R-9.1, table 19b), where it lists acceptable "isoalkyl group" names:
Some related isomeric alkyls mentioned in this section are
There are also some other, unsaturated "isoalkyl" group names mentioned:
From the above we can induce that "iso-" prefix, when related to alkanes or alkyl groups, it means the simplest (n-)alkane/alkyl isomer branched at the end of the carbon chain.
Isopropyl happens to be secondary (sec) alkyl (there's lack of carbon atoms to create primary alkyl isomeric to the n-propyl), all higher isoalkyls are primary (no branching at the alkyl "attachment").
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