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Write IUPAC names for these alkanes
Chapter 2, Problem 2.3(choose chapter or problem)
Write IUPAC names for these alkanes.
Questions & Answers
QUESTION:
Write IUPAC names for these alkanes.
ANSWER:Key concepts
IUPAC nomenclature
The International Union of Pure and Applied Chemistry's (IUPAC) nomenclature of organic chemistry is a method of naming organic chemical compounds.
Prefixes Used in the IUPAC System to Show the Presence of 1 to 20 Carbon Atoms in an Unbranched Chain
Prefix |
Number of carbon atom |
Prefix |
Number of carbon atom |
meth- |
1 |
undec- |
11 |
eth- |
2 |
dodec- |
12 |
prop- |
3 |
tridec- |
13 |
but- |
4 |
tetradec- |
14 |
pent- |
5 |
pentadec- |
15 |
hex- |
6 |
hexadec- |
16 |
hept- |
7 |
heptadec- |
17 |
oct- |
8 |
octadec- |
18 |
non- |
9 |
nonadec- |
19 |
dec- |
10 |
eicos- |
20 |
The rules of the IUPAC system for naming alkanes follow
1. The name for an alkane with an unbranched chain of carbon atoms consists of a prefix showing the number of carbon atoms in the chain and the ending -ane.
2. For branched-chain alkanes, select the longest chain of carbon atoms as the parent chain; its name becomes the root name.
3. Give each substituent on the parent chain a name and a number. The number shows the carbon atom of the parent chain to which the substituent is bonded. Use a hyphen to connect the number to the name.
4. If there is one substituent, number the parent chain from the end that gives the substituent the lower number.
5. If there are two or more identical substituents, number the parent chain from the end that gives the lower number to the substituent encountered first. The number of times the substituent occurs is indicated by the prefix di-, tri-, tetra-, penta-, hexa-, and so on. A comma is used to separate position numbers.
6. If there are two or more different substituents, list them in alphabetical order and number the chain from the end that gives the lower number to the substituent encountered first. If there are different substituents in equivalent positions on opposite ends of the parent chain, give the substituent of lower alphabetical order the lower number.
7. The prefixes di-, tri-, tetra-, and so on, are not included in alphabetizing. Alphabetize the names of the substituents first and then insert these prefixes. In the following example, the alphabetizing parts are ethyl and methyl, not ethyl and dimethyl.
Where there are two or more parent chains of identical length, choose the parent chain with the greater number of substituents.
Step 1 of 3
We have to write the IUPAC name for the alkanes given
The International Union of Pure and Applied Chemistry's (IUPAC) nomenclature of organic chemistry is a method of naming organic chemical compounds.