Unit 14a: Functional group chemistry for designer molecules
Introduction:
rganic chemistry is the study of compounds containing carbon, which are essential to life and have
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a wide range of applications in industry, medicine, and agriculture. In this assignment, we will
explore the reactions of a variety of functional groups, including carbonyls and non-carbonyls, and
the mechanisms behind them. We will also plan multi-step syntheses of organic molecules, involving
multiple reaction steps to produce a desired product. Through this assignment, we will gain a deeper
understanding of the fundamental concepts of organic chemistry and how to apply them to practical
problems.
Reactions of Carbonyl and Non-Carbonyl Functional Group Compounds
Carbonyl functional groups are found in a variety of organic compounds, including aldehydes,
ketones, carboxylic acids, esters, and amides. These compounds undergo a range of reactions,
including nucleophilic addition, nucleophilic substitution, oxidation, and reduction.
Nucleophilic addition is a common reaction of carbonyl compounds. This reaction involves the
addition of a nucleophile, such as a Grignard reagent or an alkoxide ion, to the carbonyl carbon. The
resulting product is an alcohol or a related derivative. For example, when acetaldehyde is treated
with sodium borohydride, it undergoes nucleophilic addition to form ethoxide and ethanol:
CH3CHO + NaBH4 + H2O → CH3CH2OH + NaBO2 + H2
Nucleophilic substitution is another important reaction of carbonyl compounds. This reaction
involves the substitution of a leaving group from the carbonyl carbon with a nucleophile. This
reaction is common in carboxylic acids and esters. For example, when ethyl acetate is treated with
hydroxide ion, it undergoes nucleophilic substitution to form sodium acetate and ethanol:
CH3CO2C2H5 + NaOH → CH3CO2Na + C2H5OH
Oxidation and reduction reactions are also important reactions of carbonyl compounds. Aldehydes
can be oxidized to carboxylic acids, while ketones cannot. This reaction is commonly achieved
through the use of oxidizing agents, such as potassium permanganate or chromic acid. For example,
when propanal is treated with potassium permanganate, it undergoes oxidation to form propanoic
acid:
CH3CH2CHO + KMnO4 + H2O → CH3CH2COOH + KOH + MnO2
Non-carbonyl functional groups, such as alcohols and amines, also undergo a variety of reactions.
Alcohols can be oxidized to form aldehydes, ketones, and carboxylic acids. They can also undergo
dehydration to form alkenes. Amines can act as bases or nucleophiles. Primary amines can undergo
substitution to form secondary and tertiary amines, while secondary amines can undergo
substitution to form tertiary amines.
Section 1: Halogenoalkanes and their reactions
,Halogenoalkanes, also known as alkyl halides, are organic compounds that contain one or more
halogen atoms (fluorine, chlorine, bromine or iodine) attached to a carbon atom in a hydrocarbon
chain. They undergo various reactions, including nucleophilic substitution and elimination reactions.
1. Nucleophilic substitution reaction:
Nucleophilic substitution reactions involve the substitution of a halogen atom with a nucleophile.
The general equation for a nucleophilic substitution reaction is:
R-X + Nu- → R-Nu + X-
where R represents the alkyl group, X is the halogen atom, Nu is the nucleophile and - represents the
bond.
There are two main mechanisms of nucleophilic substitution reactions: the SN1 (substitution
nucleophilic unimolecular) and SN2 (substitution nucleophilic bimolecular) mechanisms. The SN1
mechanism involves a two-step process, whereas the SN2 mechanism involves a single-step process.
2. Elimination reaction:
Elimination reactions involve the removal of a halogen atom and a hydrogen atom from adjacent
carbon atoms, resulting in the formation of a double bond. The general equation for an elimination
reaction is:
R-X → R-H + X-
where R represents the alkyl group, X is the halogen atom, and - represents the bond.
One common example of a commercially important product formed through halogenoalkane
reactions is Freon-12 (CCl2F2), a chlorofluorocarbon compound used as a refrigerant.
Section 2: Alcohols and their reactions
Alcohols are organic compounds that contain a hydroxyl (-OH) group attached to a carbon atom in a
hydrocarbon chain. They can be classified as primary (1°), secondary (2°), or tertiary (3°), based on
the number of alkyl groups attached to the carbon atom bearing the hydroxyl group. Alcohols
undergo oxidation reactions to form carbonyl compounds.
1. Oxidation reaction:
, Alcohols can be oxidized to form aldehydes, ketones or carboxylic acids. The oxidation reaction
depends on the type of alcohol. Primary alcohols are oxidized to aldehydes and then to carboxylic
acids, while secondary alcohols are oxidized to ketones.
The oxidation of a primary alcohol to an aldehyde can be shown by the following equation:
R-CH2OH + [O] → R-CHO + H2O
The oxidation of a primary alcohol to a carboxylic acid can be shown by the following equation:
R-CH2OH + 2[O] → R-COOH + H2O
2. Reduction reaction:
Alcohols can be reduced to form alkanes or alkyl halides. The reduction reaction depends on the
type of alcohol.
One example of a commercially important product formed through alcohol reactions is ethanol
(C2H5OH), an alcohol commonly used as a solvent and fuel.
Section 3: Amines and their reactions
Amines are organic compounds that contain a nitrogen atom with one, two or three alkyl or aryl
groups attached to it. They can be classified as primary (1°), secondary (2°), or tertiary (3°), based on
the number of alkyl or aryl groups attached to the nitrogen atom. Amines can act as both bases and
nucleophiles.
1. Basic reaction:
Introduction:
rganic chemistry is the study of compounds containing carbon, which are essential to life and have
O
a wide range of applications in industry, medicine, and agriculture. In this assignment, we will
explore the reactions of a variety of functional groups, including carbonyls and non-carbonyls, and
the mechanisms behind them. We will also plan multi-step syntheses of organic molecules, involving
multiple reaction steps to produce a desired product. Through this assignment, we will gain a deeper
understanding of the fundamental concepts of organic chemistry and how to apply them to practical
problems.
Reactions of Carbonyl and Non-Carbonyl Functional Group Compounds
Carbonyl functional groups are found in a variety of organic compounds, including aldehydes,
ketones, carboxylic acids, esters, and amides. These compounds undergo a range of reactions,
including nucleophilic addition, nucleophilic substitution, oxidation, and reduction.
Nucleophilic addition is a common reaction of carbonyl compounds. This reaction involves the
addition of a nucleophile, such as a Grignard reagent or an alkoxide ion, to the carbonyl carbon. The
resulting product is an alcohol or a related derivative. For example, when acetaldehyde is treated
with sodium borohydride, it undergoes nucleophilic addition to form ethoxide and ethanol:
CH3CHO + NaBH4 + H2O → CH3CH2OH + NaBO2 + H2
Nucleophilic substitution is another important reaction of carbonyl compounds. This reaction
involves the substitution of a leaving group from the carbonyl carbon with a nucleophile. This
reaction is common in carboxylic acids and esters. For example, when ethyl acetate is treated with
hydroxide ion, it undergoes nucleophilic substitution to form sodium acetate and ethanol:
CH3CO2C2H5 + NaOH → CH3CO2Na + C2H5OH
Oxidation and reduction reactions are also important reactions of carbonyl compounds. Aldehydes
can be oxidized to carboxylic acids, while ketones cannot. This reaction is commonly achieved
through the use of oxidizing agents, such as potassium permanganate or chromic acid. For example,
when propanal is treated with potassium permanganate, it undergoes oxidation to form propanoic
acid:
CH3CH2CHO + KMnO4 + H2O → CH3CH2COOH + KOH + MnO2
Non-carbonyl functional groups, such as alcohols and amines, also undergo a variety of reactions.
Alcohols can be oxidized to form aldehydes, ketones, and carboxylic acids. They can also undergo
dehydration to form alkenes. Amines can act as bases or nucleophiles. Primary amines can undergo
substitution to form secondary and tertiary amines, while secondary amines can undergo
substitution to form tertiary amines.
Section 1: Halogenoalkanes and their reactions
,Halogenoalkanes, also known as alkyl halides, are organic compounds that contain one or more
halogen atoms (fluorine, chlorine, bromine or iodine) attached to a carbon atom in a hydrocarbon
chain. They undergo various reactions, including nucleophilic substitution and elimination reactions.
1. Nucleophilic substitution reaction:
Nucleophilic substitution reactions involve the substitution of a halogen atom with a nucleophile.
The general equation for a nucleophilic substitution reaction is:
R-X + Nu- → R-Nu + X-
where R represents the alkyl group, X is the halogen atom, Nu is the nucleophile and - represents the
bond.
There are two main mechanisms of nucleophilic substitution reactions: the SN1 (substitution
nucleophilic unimolecular) and SN2 (substitution nucleophilic bimolecular) mechanisms. The SN1
mechanism involves a two-step process, whereas the SN2 mechanism involves a single-step process.
2. Elimination reaction:
Elimination reactions involve the removal of a halogen atom and a hydrogen atom from adjacent
carbon atoms, resulting in the formation of a double bond. The general equation for an elimination
reaction is:
R-X → R-H + X-
where R represents the alkyl group, X is the halogen atom, and - represents the bond.
One common example of a commercially important product formed through halogenoalkane
reactions is Freon-12 (CCl2F2), a chlorofluorocarbon compound used as a refrigerant.
Section 2: Alcohols and their reactions
Alcohols are organic compounds that contain a hydroxyl (-OH) group attached to a carbon atom in a
hydrocarbon chain. They can be classified as primary (1°), secondary (2°), or tertiary (3°), based on
the number of alkyl groups attached to the carbon atom bearing the hydroxyl group. Alcohols
undergo oxidation reactions to form carbonyl compounds.
1. Oxidation reaction:
, Alcohols can be oxidized to form aldehydes, ketones or carboxylic acids. The oxidation reaction
depends on the type of alcohol. Primary alcohols are oxidized to aldehydes and then to carboxylic
acids, while secondary alcohols are oxidized to ketones.
The oxidation of a primary alcohol to an aldehyde can be shown by the following equation:
R-CH2OH + [O] → R-CHO + H2O
The oxidation of a primary alcohol to a carboxylic acid can be shown by the following equation:
R-CH2OH + 2[O] → R-COOH + H2O
2. Reduction reaction:
Alcohols can be reduced to form alkanes or alkyl halides. The reduction reaction depends on the
type of alcohol.
One example of a commercially important product formed through alcohol reactions is ethanol
(C2H5OH), an alcohol commonly used as a solvent and fuel.
Section 3: Amines and their reactions
Amines are organic compounds that contain a nitrogen atom with one, two or three alkyl or aryl
groups attached to it. They can be classified as primary (1°), secondary (2°), or tertiary (3°), based on
the number of alkyl or aryl groups attached to the nitrogen atom. Amines can act as both bases and
nucleophiles.
1. Basic reaction:
