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IUPAC nomenclature is based on naming a molecule's longest chain of carbons Nomenclature of Molecules Containing Substituents and Functional Groups. to produce was a version of IUPAC rules that would be relatively complete and allow the beginner to explore and learn about nomenclature as much or as little. P Introduction. P Selecting the preferred type of nomenclature. P Selecting preferred IUPAC names and preselected names (see P) for.

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Iupac Nomenclature Pdf

vide basic rules and examples for naming monofunctional compounds. However, students of more advanced organic chemistry courses and graduate students. organic nomenclature are based on the definitive rules published by I.U.P.A.C.1 ( the. International Union of Pure and Applied Chemistry). 2. HYDROCARBONS. The IUPAC system of nomenclature was established at various functional classes organic compounds, as well as the relationship between compounds that .

In order to name organic compounds you must first memorize a few basic names. These names are listed within the discussion of naming alkanes. In general, the base part of the name reflects the number of carbons in what you have assigned to be the parent chain. The suffix of the name reflects the type s of functional group s present on or within the parent chain. Other groups which are attached to the parent chain are called substituents. Alkanes - saturated hydrocarbons The names of the straight chain saturated hydrocarbons for up to a 12 carbon chain are shown below. The names of the substituents formed by the removal of one hydrogen from the end of the chain is obtained by changing the suffix - ane to - yl. There are a few common branched substituents which you should memorize. These are shown below. Here is a simple list of rules to follow.

For the common name of aldehydes start with the common parent chain name and add the suffix -aldehyde. Substituent positions are shown with Greek letters.

Table of Functional Group Priorities for Nomenclature

When the -CHO functional group is attached to a ring the suffix -carbaldehyde is added, and the carbon attached to that group is C1. Aldehyde Common Names to Memorize There are some common names that are still used and need to be memorized.

Recognizing the patterns can be helpful. A ketone carbonyl function may be located anywhere within a chain or ring, and its position is usually given by a location number. Chain numbering normally starts from the end nearest the carbonyl group.

Very simple ketones, such as propanone and phenylethanone do not require a locator number, since there is only one possible site for a ketone carbonyl function. The common names for ketones are formed by naming both alkyl groups attached to the carbonyl then adding the suffix -ketone. The attached alkyl groups are arranged in the name alphabetically.

Summary of Ketone Nomenclature rules Ketones take their name from their parent alkane chains. The ending -e is removed and replaced with -one. Some common ketones are known by their generic names. Number the carbons in the carbon chain In this case, it doesn't matter whether you start numbering from the left or right. The hydroxyl group will still be attached to second carbon atom ol. Combine the elements of the compound's name into a single word in the order of branched groups; prefix; name ending according to the functional group The compound's name is propanol or 2-propanol.

There are two hydroxyl groups in the compound, so the suffix will be -diol.

Nomenclature of Aldehydes & Ketones - Chemistry LibreTexts

Find the longest carbon chain that contains the functional group There are four carbon atoms in the longest chain that contains the functional group but- and only single bonds an-.

The prefix for this compound will be butan-. Number the carbons in the carbon chain There are two hydroxyl groups attached to the main chain. If we number as shown in red on the left they are attached to the first and second carbon atoms. If we number as shown in blue on the right they are attached to the third and fourth carbon atoms. The functional groups should have the lowest numbers possible.

Therefore the red numbering is correct. The hydroxyl groups are attached to the first and second carbon atoms 1,2-diol. Combine the elements of the compound's name into a single word in the order of branched groups; prefix; name ending according to the functional group The compound's name is butan-1,2-diol.

Worked example Naming the alcohols Draw the structural and condensed structural representations for the organic compound 4-ethyloctan-2,5-diol Identify the functional group The compound has the suffix -ol.

It is therefore an alcohol.

Find the longest carbon chain that contains the functional group The prefix is oct- therefore there are 8 carbons in the longest chain containing the functional group. If you don't have an atomic model kit remember that you can use jelly tots or playdough and toothpicks. Use different colour jelly tots to represent the different atoms.

Remember, they belong to the homologous series of the alcohols. What is the general formula for this series? Try placing the hydroxyl group at different positions within the molecule. Does this make any difference to the total number of carbon, hydrogen and oxygen atoms in the molecule? Naming alcohols Give the structural representation of each of the following organic compounds: pentanol The prefix pentan- tells us there are five carbon atoms in the longest chain and only single carbon-carbon bonds.

The suffix -2,3-diol tells us there are two hydroxyl groups, one attached to the second carbon atom and one attached to the third carbon atom.

The suffix ol tells us there is a hydroxyl group attached to the first carbon atom. There are only single carbon-carbon bonds, therefore the prefix becomes butan-. The hydroxyl group is attached to the second carbon atom.

The molecule is 2-butanol or butanol.

The hydroxyl group is given the lowest possible number and so this compound is not butanol. There is a hydroxyl group, therefore the compound is an alcohol and the suffix is -ol. There are five carbon atoms in the longest chain so the prefix is pent-. There are only single carbon-carbon bonds, therefore the prefix becomes pentan-.

The molecule is 2-pentanol or pentanol. The hydroxyl group is given the lowest possible number and so this compound is not pentanol. There are two hydroxyl groups, therefore the compound is an alcohol and the suffix is -diol. There are seven carbon atoms in the longest chain so the prefix is hept-. There are only single carbon-carbon bonds, therefore the prefix becomes heptan-. The hydroxyl groups are both attached to the third carbon atom -3,3-diol. The branched methyl chain is attached to the fourth carbon atom.

The molecule is 4-methylheptan-3,3-diol. The hydroxyl groups are given the lowest possible numbers and so this compound is not 4-methylheptan-5,5-diol. There are many different functional groups that contain a carbonyl group. Naming aldehydes If the carbonyl group is on the end of the carbon chain, the organic compound is called an aldehyde.

An aldehyde has the suffix -al. It is therefore either an aldehyde or a ketone. The carbonyl group is on the last terminal carbon in the main chain so the compound is an aldehyde. It will have the suffix -al.

Find the longest carbon chain containing the functional group There are three carbons in the longest chain that contains the functional group. As there are only single bonds between the carbon atoms, the prefix becomes propan-. Number the carbon atoms in the carbon chain The carbon atoms will be numbered so that the carbon atom of the aldehyde group has the lowest number possible.

In this case that is from right to left.

Look for any branched groups There are no branched groups in this compound. Combine the elements of the compound's name into a single word in the order of branched groups; prefix; name ending according to the functional group The compound's name is propanal there is no need to say propanal as by definition all aldehydes are al.

Remember that there is no structural information given by the molecular formula Naming ketones Ketone is pronounced keytone. Therefore propanone is pronounced propanown. If the carbonyl group is in the middle of the carbon chain, the compound is called a ketone. A ketone has the suffix -one. Note that butanone can only be butanone. If the carbonyl group were on carbon 1 it would be an aldehyde, while if it were on carbon 3 we would simply count from the other side of the molecule.

The carbonyl group is not at the end of the chain. Therefore the compound is a ketone and the suffix will be -one. Find the longest carbon chain containing the functional group There are four carbons in the longest chain that contains the functional group, and only single carbon-carbon bonds. Number the carbon atoms in the carbon chain The carbon atoms will be numbered from left to right so that the carbon atom of the ketone group has the lowest number possible one. Combine the elements of the compound's name into a single word in the order of branched groups; prefix, name ending according to the functional group The compound's name is butanone or 2-butanone.

Find the longest carbon chain that contains the functional group The longest carbon chain that contains the functional group has four carbon atoms in it, and only single bonds.

Number the carbon atoms in the carbon chain The carbon atoms will be numbered from left to right so that the carbon atom of the ketone functional group has the lowest possible number. The suffix will be one. Look for any branched groups There is a branched group on carbon 3.

This group has only one carbon atom.

Nomenclature of Aldehydes & Ketones

The branched group is attached to the third carbon atom 3-methyl. Combine the elements of the compound's name into a single word in the order of branched groups; prefix; name ending according to the functional group The compound's name is 3-methylbutanone.

Worked example Naming carbonyl compounds Draw the structural and condensed structural representations for the organic compound 3-methylpentanal.

Identify the functional group The compound has the suffix -al. If there are two or more chains competing for selection as the parent chain chain with the most multiple bonds , the choice goes to 1 the chain with the greatest number of carbon atoms, 2 the of carbon atoms being equal, the chain containing the maximum number of double bonds.

If there is a choice in numbering not previously covered, the parent chain is numbered to give the substituents the lowest number at the first point of difference.

Here are some examples: Alcohols Alcohols are named by replacing the suffix -ane with -anol. If there is more than one hydroxyl group -OH , the suffix is expanded to include a prefix that indicates the number of hydroxyl groups present -anediol, -anetriol, etc. The position of the hydroxyl group s on the parent chain is are indicated by placing the number s corresponding to the location s on the parent chain directly in front of the base name same as alkenes.

Here is an important list of rules to follow: The hydroxyl group takes precedence over alkyl groups and halogen substituents, as well as double bonds, in the numbering of the parent chain.

When both double bonds and hydroxyl groups are present, the -en suffix follows the parent chain directly and the -ol suffix follows the -en suffix notice that the e is left off, -en instead of -ene. The location of the double bond s is are indicated before the parent name as before, and the location of the hydroxyl group s is are indicated between the -en and -ol suffixes.

Again, the hydroxyl gets priority in the numbering of the parent chain. Here are some examples: Ethers You are only expected to know how to name ethers by their commmon names. The two alkyl groups attached to the oxygen are put in alphabetical order with spaces between the names and they are followed by the word ether.

The prefix di- is used if both alkyl groups are the same. Here are some examples: Aldehydes Aldehydes are named by replacing the suffix -ane with -anal. If there is more than one -CHO group, the suffix is expanded to include a prefix that indicates the number of -CHO groups present -anedial - there should not be more than 2 of these groups on the parent chain as they must occur at the ends.

It is not necessary to indicate the position of the -CHO group because this group will be at the end of the parent chain and its carbon is automatically assigned as C Here is an important list of rules to follow: The carbonyl group takes precedence over alkyl groups and halogen substituents, as well as double bonds, in the numbering of the parent chain.

When both double bonds and carbonyl groups are present, the -en suffix follows the parent chain directly and the -al suffix follows the -en suffix notice that the e is left off, -en instead of -ene. The location of the double bond s is are indicated before the parent name as before, and the -al suffix follows the -en suffix directly.

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