Organic Families:Amines

Karolina GalasRebecca Correia

Michael Rego Ashley Chaves

H

H N H

HH N H

What is an Amine?Amine: An ammonia molecule in which one or more H

atoms are substituted by alkyl or aromatic groups.

Amines are a type of organic molecule that is derived from ammonia.

Amines are simpler organic compounds that form when large and complex molecules, such as proteins, break down when organisms decompose. (Textbook 69)

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Structure & Functional Group• Amines are characterized by how many hydrogen

atoms have been substituted for carbon chains.

H H H N H R N H

Ammonia Primary Amine

R’ R’ R N H R N R” Secondary Amine Tertiary Amine

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Primary Amines (1°)Only one hydrogen atom in the ammonia

molecule has been replaced by a carbon chain.The alkyl groups in an amine may be identical or

different. Examples:

Secondary Amines (2°)Two hydrogen atoms have been replaced by C-

chains.Examples:

Tertiary Amines (3°)All (3) hydrogen atoms have been replaced by C-

chains.Examples:

Physical and Chemical PropertiesAmines are liquid or gasses at SATP.

As with many compounds of nitrogen, such as ammonia, NH3, amines often have an unpleasant odour (69) For example, the smell of rotting fish is due to a mixture of ammines.

Example : Amines are alkaline based and lemon juice is acidic in nature, thus mixing the two neutralizes the effect of each other. Using lemon, vinegar or baking soda will reduce the smell of the mixing amines.

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Electronegativity and Polarity:Amines have higher boiling and melting points

than hydrocarbons of similar size, and the smaller amines are readily soluble in water.

This can be explained by two types of polar bonds in amines: the N-C bond and any N-H bonds.

These bonds are polar because N is more electronegative than either C or H.

Boiling and Melting PointsThe polar bonds present increase

intermolecular forces of attraction, and therefore, higher temperatures are required to melt or vaporize amines (72)

Where N-H bonds are present, hydrogen bonding also occurs with water molecules, accounting for the high solubility of amines in water.

Since N-H bonds are less polar than O-H bonds, amines boil at lower temperatures than do alcohols of the same size. For example,

Hydrocarbon b.p. (°C)

Amine b.p. (°C)

Alcohol b.p. (°C)

C4H9CH3 36 C4H9NH2 78 C4H9OH 117

Boiling and Melting Points Continued:Primary Secondary Tertiary

Boiling Point Example (°C)

CH3CH2NH2

16.6(CH3)2NH7.4

(CH3)3N3.5

Boiling Point Explanation

The reason for the higher boiling points of the primary amines is that they can form hydrogen bonds with each other as well as van der Waals dispersion forces and dipole-dipole interactions. The boiling points increase as you increase chain length because of the greater amount of van der Waals dispersion forces between the bigger molecules.

Secondary amines still form hydrogen bonds, but having the nitrogen atom in the middle of the chain rather than at the end makes the permanent dipole on the molecule slightly less. The lower boiling point is due to the lower dipole-dipole attractions in the dimethylamine compared with ethylamine.

In a tertiary amine there aren't any hydrogen atoms attached directly to the nitrogen. That means that hydrogen bonding between tertiary amine molecules is impossible. That's why the boiling point is much lower.

Melting points appear in the same order!

Solubility Where N-H bonds are present, hydrogen bonding

also occurs with water molecules, accounting for the high solubility of amines in water. It is worth noticing that since N-H bonds are less polar than O-H bonds, amines boil at lower temperatures than do alcohols of similar size. (Table 2-pg. 72)

The small amines of all types are very soluble in water.

They all for hydrogen bonds. Although the tertiary amines don't have a hydrogen atom attached to the nitrogen and so can't form hydrogen bonds with themselves, they can form hydrogen bonds with water molecules just using the lone pair on the nitrogen.

Nomenclature IUPAC method Classical method

Amines are named as substituents on the longest alkyl group.

Aminoethane

The suffix “-amine” is attached to the root alkyl name.

Ethylamine

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Nomenclature To-Do list:Using the IUPAC system

1. Identify the longest carbon chain that is connected to the nitrogen.

2. Start numbering closest to the functional group (ammonia).

3. State where the functional group is attached to the longest carbon chain.

Alphabetize the branches

Attach

ment to F.

G.

amino Longest carbon chain

Examples of Nomenclature

UsesAmino Acids (proteins)Medical Applications : Anesthetics, Serotonin

(Neurotransmitter in the brain), Recreational Drugs ( amphetamines and methamphetamines ) morphine (analgesics), Epipens.Dissolves quickly in our blood stream

Pest controlCaffeine Pesticides Explosives

Amino Acids (Proteins):Amino Acid: a compound in which an amino

group and a carboxyl group are attached to the same carbon atom.

They are amphoteric

Amino acids are the monomer subunit of proteins which serve various functions in the human body such as : hair, tendons, ligaments, antibodies, hormones, hemoglobin and amylase.

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Serotonin : Neurotransmitter in the brain:Serotonin is generally considered to be an

important amine, as it functions as one of the primary neurotransmitters used by the brain

It regulates feelings of heat and hunger, and controls how fast the brain operates and affects feelings of happiness as well as regulating the sleeping cycle.

Amphetamine is used in antidepressants increase serotonin

Industrial Processes:Examples of direct uses of amines and

their salts are as corrosion inhibitors in boilers and in lubricating oils

Like ammonia, amines are bases, meaning that they have a pH of above seven. Due to this fact they can be neutralized by acids.

Corrosion inhibitors help to prevent corrosion from acids by using amines to neutralize the acid

Reactions With Other Hydrocarbons73

Reaction Steps 1. Start with an alkyl halide (carbon chain with a halogen)2. React the alkyl halide with ammonia 3. The halogen element, and a hydrogen atom for the

ammonia will be removed and form their own compound 4. The remainder of the ammonia and the hydrogen chain

combine to make one compound. (primary amine)5. This reaction can occur numerous times by reacting the

amine with an alkyl halide6. Each time, the halogen is removed, and a hydrogen from

the ammonia is replaced by the remainder of the carbon chain from the alkyl halide.

Note: no special conditions are needed in a reaction as the ammonia or amine is reacting with an alkyl halide.

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Reaction ExampleAlkyl Halide reacting with a halogen to produce a primary amine

CH3CH2-I + H-N-H CH3CH2-N-H + HI | | H H Ethyl Iodide Ammonia Ethylamine (1° amine )

The primary amine formed still has hydrogen atoms, meaning that it can still react with alkyl halides.

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Reaction ExamplePrimary amine reacting with alkyl halide to produce secondary amine

CH3CH2-I + CH3CH2-N-H CH3CH2-N-CH2-CH3 + HI | | H H Ethyl Iodide Ethylamine Diethylamine (1° amine ) (2° amine)

The secondary amine formed can still react with an alkyl halide to yield another product.

Reaction ExampleSecondary amine reacting with alkyl halide to produce tertiary amine

CH3CH2-I +CH3CH2-N-CH2-CH3 CH3CH2-N-CH2-CH3+ HI | | H CH2CH3Ethyl Iodide Diethylamine Triethylamine (2° amine) (3° amine)

The final product is a tertiary amine, all of the hydrogen atoms of the ammonia have been replaced by carbon chains from the alkyl halide in the solution

Expansion on Reactions:

A primary, secondary or tertiary amine inconcentrated sulphuric acid can react with a carboxylic acid to produce an amide and water

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Organic Family Amine

Type of Reaction

Substitution(Rx with alkyl halides) ( 1°, 2°, 3°)

Reactant 1(Organic Family)

Ammonia

Reactant 2(Organic Family)

Alkyl Halide

(Structure, names, special conditions)

Alkyl Halide reacting with a halogen to produce a primary amine

CH3CH2-I + H-N-H CH3CH2-N-H + HI | | H H Ethyl Iodide Ammonia Ethylamine (1° amine )

Special Conditions

No special condition is required as a Halogen is present

Bibliography http://hyperphysics.phy-astr.gsu.edu/hbase/organic/amine.htmlhttp://www.chemguide.co.uk/organicprops/amines/background.

htmlhttp://

www2.chemistry.msu.edu/faculty/reusch/VirtTxtJml/amine1.htm

http://www.wisegeek.com/what-are-amines.htmhttp://

www.chemguide.co.uk/organicprops/amines/background.html

Fraser, D., LeDrew, B., Vavitsas, A., & White-McMahon, M. (2012).In L. Cahill, D. Davies-Wright & R. Rosenlum (Eds.),  (2 ed., pp. 41). Toronto, ON: Nelson Education Ltd.

http://www.digitalrefining.com/article/1000509,Choosing_a_neutralising_amine_corrosion_inhibitor.html#.UpqRfnCEgcA