1.4 Hydrocarbon Derivatives - Double Bonded PDF

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HYDROCARBON DERIVATIVES - DOUBLE BONDED

Aldehydes ● ● ● ●

Carbonyl group: a functional group in which a carbon atom is double bonded to an oxygen atom Formyl group: a functional group in which a carbon atom is double bonded to an oxygen atom and single bonded to a hydrogen atom Aldehyde: a hydrocarbon derivative that contains a formyl group At the end of a carbon chain

Nomenclature for Aldehydes ● ● ● ● ● ●

Identify the longest carbon chain that contains the formyl group. If there is a longer carbon chain without the formyl group present, it will be named as a substituent. Number the chain so that the formyl group(s) has the lowest possible number(s). Use the IUPAC naming system to name the prefixes of the parent alkane. Remove the –e from the parent alkane, and then add the suffix –al. There are no numbers in the suffix because the formyl group is always on the first carbon. Any alkyl groups come before the name of the aldehyde.

Properties of Aldehydes ● ● ● ● ●

Carbonyl group of aldehyde very polar but C-H is not therefore aldehydes do not hydrogen bond with each other, but they can hydrogen bond with water Strength of attraction among aldehydes not as strong as that between alcohol molecules Boiling points are lower than alcohols Small aldehydes (1-4 carbons) are soluble in water, longer chains are increasingly insoluble in water Short chain aldehydes have strong odour

Ketones ●

Ketone: a hydrocarbon derivative that contains a carbonyl group that is bonded to two carbon atoms or carbon chains

Nomenclature for Ketones ● ● ●

Identify the longest carbon chain that contains the carbonyl group. If there is a longer carbon chain without the carbonyl group present, it will be named as a substituent. Number the chain so that the carbonyl group(s) has the lowest possible number(s). Use the IUPAC naming system to name the prefixes of the parent alkane.

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Remove the –e from the parent alkane, and then add the suffix –one. Name the prefix of the ketone like another branch to indicate the ketone group’s position with its number and a hyphen imbedded in the name of the ketone. Any alkyl groups come before the name of the ketone.

Properties of Ketones ● ●

Carbonyl group of ketone very polar but no hydrogen so does not hydrogen bond with each other, but they can hydrogen bond with water Therefore ketones have similar boiling points and solubilities to those of aldehydes of similar length

Carboxylic Acids ● ●

Carboxylic acid: a hydrocarbon derivative that contains a carboxyl group Carboxyl group: a functional group made up of a carbonyl group with a hydroxyl group attached to it

Nomenclature for Carboxylic Acids ● ● ● ● ● ●

Identify the longest carbon chain that contains the carboxyl group. If there is a longer carbon chain without the carboxyl group present, it will be named as a substituent. Number the chain so that the carboxyl group(s) has the lowest possible number(s). Use the IUPAC naming system to name the prefixes of the parent alkane. Remove the –e from the parent alkane, and then add the suffix –oic acid. There are no numbers in the suffix because the carboxyl group is always on the first carbon. Any alkyl groups come before the name of the carboxylic acid.

Properties of Carboxylic Acids ● ● ● ● ●

Presence of both a C=O group and –OH group make the carboxyl group very polar Can hydrogen bond to each other as well as water Boiling points much higher than corresponding hydrocarbons and other functional groups Smaller carboxylic acids are soluble in water but get increasingly insoluble as number of carbons increase Carboxylic acids are weak acids

Esters ● ●

Ester: a hydrocarbon derivative that contains a functional group with a carbon atom double bonded to one oxygen atom and single bonded to another Can help to think of an ester as a combination of a carboxylic acid and an alcohol

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Nomenclature for Esters ●

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Identify the part of the ester that contains the carbonyl group (C=O); this is the part that comes from the carboxylic acid. The root for the ester is based on this end of the molecule. Name the carboxylic acid. Drop the –oic acid suffix and add the suffix –oate. To form the prefix, consider the other end of the molecule that is associated with the alcohol. Ignore the oxygen atom and name only the alkyl group to write the prefix. This part of the prefix is placed first when naming the ester If there are any branches on the part of the molecule that comes from the carboxylic acid, name it as you would with a simple hydrocarbon. The branch name(s) come after the prefix associated with the alcohol end of the molecule.

Properties of Esters ● ● ● ●

Presence of both a C=O group makes esters somewhat polar, but no hydrogen bonding Therefore esters cannot hydrogen bond with one another but can with water Boiling points of esters are lower than corresponding alcohols and carboxylic acids Esters give off distinguishable aromas

Amides ● ● ● ●

Amide: a hydrocarbon derivative that contains a carbonyl group bonded to a nitrogen atom Primary: The N atom is bonded to two H atoms Secondary: The N atom is bonded to one H atom and one alkyl group Tertiary: The N atom is bonded to two alkyl groups

Nomenclature for Amides ●

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The root is based on the longest carbon chain (parent chain) that includes the carbonyl group ○ Number the chain starting with 1 at the carbonyl group “-an-” is added to the root when the parent chain has only single bonds The suffix “-amide” is added to the end Identify the location of any substituents ○ The N is listed before numbers Name the groups and place them in alphabetical order

Properties of Amides ● ● ●

Carbonyl group is polar, and like amines, polarity of N atom depends on whether amide is a primary, secondary or tertiary amide Primary and secondary amides, which have at least one H bonded to the N atom, are soluble Melting and boiling points are higher in primary and secondary amides (hydrogen bonding is very strong and hard to break)

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Amides have the highest melting and boiling points of any organic compounds

Priorities of Functional Groups ●

When more than one functional group exists on an organic compound, the priority of the functional group must be considered in order to name the compound...