chapter 1 organic chemistry chemistry 20. organic compounds

Chapter 1

Organic Chemistry

Chemistry 20

Organic Compounds

Organic Compounds

Chemistry of Carbon (H, O, N, S, Halogens, and P).

H: 0.9%Ti: 0.6%Others: 0.9%

C one of the 116 elements

Obtained by:

Isolation from nature (animal and plant)

Synthesis in lab

Organic compounds: 10 million

Inorganic compound: 1.7 million

Compounds in living systems are organic: Biochemistry

Organic Compounds

(extract-isolate-purify)

NH4Cl AgNCO H2N-C-NH2

OAgCl+ heat +

Ammoniumchloride

Silvercyanate

Urea Silverchloride

Organic Compounds

First organic compound that is synthesized in lab.

Wöhler (1828)

Organic Compounds

Typical organic compounds:

• Contain carbon

• Have covalent bonds

• Have low melting points

• Have low boiling points

• Are flammable (all burn)

• Are soluble in nonpolar solvents

• May be gases, liquids or solids

C3H8

Propane

Organic Compounds Inorganic Compounds

Bonding is almost entirely covalentMay be gases, liquids, or solidswith low melting points (lessthan 360°C)Most are insoluble in waterMost are soluble in organic solventssuch as diethyl ether, toluene, and dichloromethaneAqueous solutions do notconduct electricityAlmost all burn

Reactions are usually slow

Most have ionic bondsMost are solids with high melting points

Many are soluble in waterAlmost all are insoluble in organic solvents

Aqueous solutions conductelectricityVery few burn

Reactions are often very fast

Organic Compounds

shows the atoms present in a molecule as well as

the bonds that connect them.

Structural Formula (Lewis Structure)

H-C-C-H

H

H H

H H

HC C

H

HH-C C-H

H-C-O-H

H

H

HC O

HH-C-N-HH

HH

HN

H HC

H-C-C-Cl

H

H H

H

Ethane(bond angles

109.5°)

Ethylene(bond angles

120°)

Acetylene(bond angles

180°)

Methanol(bond angles

109.5°)

Formaldehyde(bond angles

120°)

Methanamine(bond angles

109.5°)

Methyleneimine(bond angles 120°)

Chloroethane(bond angles

109.5°)

::

::::

::

:

VSEPR Model

VSEPR: Valence-Shell Electron-Pair Repulsion method

Bond angle: angle between two atoms bonded to a central atom.

Each region of electron likes to be as far away as possible from the others.

Regions of electron density

Four regions of electron density around an atom:

Bond Angles & Geometric Structures

Linear molecules

Trigonal planarmolecules

Tetrahedral arrangement

2 regions

3 regions

4 regions

Tetrahedral Electron Pair Geometry(Tetrahedral arrangement)

H2OCH4 NH3

Tetrahedral Electron Pair Geometry

Unshared electron paires

– Carbon: normally forms four covalent bonds and has no unshared pairs of electrons.

– Hydrogen: forms one covalent bond and no unshared pairs of electrons.

– Nitrogen: normally forms three covalent bonds and has one unshared pair of electrons.

– Oxygen: normally forms two covalent bonds and has two unshared pairs of electrons.

– A Halogen: normally forms one covalent bond and has three unshared pairs of electrons.

C

H

N

O =....

..

Cl.... ..

An atom or group of atoms within a molecule that shows a characteristic set of predictable physical and chemical properties.

– A way to classify organic compounds into families.

– They determine the chemical and physical properties of a compound.

– They undergo the same types of chemical reactions.

– A way to name organic compounds.

Functional groups

-OH

-NH2

-C-H

-C-

CH3CH2OH

CH3CH2NH2

CH3CHO

CH3CCH3

O

CH3COHO

-C-OH

Example

Alcohol

Amine

Aldehyde

Ketone

Carboxylic acid

Ethanol

Ethanamine

Ethanal

Acetone

Acetic acid

NameFamilyFunctionalgroup

CH3COCH2CH3

O-C-ORCarboxylic ester Ethyl acetate

O

O

O

O

Functional groups

• Alkanes: contain single bonds between carbon atoms.

• Alkenes: contain one or more double bonds.

• Alkynes: contain one or more triple bonds.

Alkanes, Alkenes, and Alkynes

CC

CC

CC

Alcohols and Ethers

C C

C C

O

O

H

• Alcohols: contain the hydroxyl (-OH) functional group.

• Ethers: an oxygen atom is bonded to two carbon atoms.

C O C

• Aldehydes: contain a carbonyl group (C=O), which is a carbon atom with a double bond to an oxygen atom.

• Ketones: the carbon of the carbonyl group is attached to two other carbon atoms.

Aldehydes and Ketones

O

O

CC

C

CC

-OH

-NH2

-C-H

-C-

CH3CH2OH

CH3CH2NH2

CH3CHO

CH3CCH3

O

CH3COHO

-C-OH

Example

Alcohol

Amine

Aldehyde

Ketone

Carboxylic acid

Ethanol

Ethanamine

Ethanal

Acetone

Acetic acid

NameFamilyFunctionalgroup

CH3COCH2CH3

O-C-ORCarboxylic ester Ethyl acetate

O

O

O

O

-OH

-NH2

-C-H

-C-

CH3CH2OH

CH3CH2NH2

CH3CHO

CH3CCH3

O

CH3COHO

-C-OH

Example

Alcohol

Amine

Aldehyde

Ketone

Carboxylic acid

Ethanol

Ethanamine

Ethanal

Acetone

Acetic acid

NameFamilyFunctionalgroup

CH3COCH2CH3

O-C-ORCarboxylic ester Ethyl acetate

O

O

O

O

H

• Carboxylic acids: contain the carboxyl group (-COOH), which is a carbonyl group attached to a hydroxyl group.

• Esters: the hydroxyl group of a carboxylic acid is replaced by a carbon

atom.

Carboxylic acids and Esters

O

O

O

O

C

C

C

C

H

-OH

-NH2

-C-H

-C-

CH3CH2OH

CH3CH2NH2

CH3CHO

CH3CCH3

O

CH3COHO

-C-OH

Example

Alcohol

Amine

Aldehyde

Ketone

Carboxylic acid

Ethanol

Ethanamine

Ethanal

Acetone

Acetic acid

NameFamilyFunctionalgroup

CH3COCH2CH3

O-C-ORCarboxylic ester Ethyl acetate

O

O

O

O

-OH

-NH2

-C-H

-C-

CH3CH2OH

CH3CH2NH2

CH3CHO

CH3CCH3

O

CH3COHO

-C-OH

Example

Alcohol

Amine

Aldehyde

Ketone

Carboxylic acid

Ethanol

Ethanamine

Ethanal

Acetone

Acetic acid

NameFamilyFunctionalgroup

CH3COCH2CH3

O-C-ORCarboxylic ester Ethyl acetate

O

O

O

O

• Amines: the functional group is a nitrogen atom.

|

— N —

• Amides: the hydroxyl group of a carboxylic acid is replaced by a nitrogen group.

Amines and Amides

O

C

C CC

NN

N

-OH

-NH2

-C-H

-C-

CH3CH2OH

CH3CH2NH2

CH3CHO

CH3CCH3

O

CH3COHO

-C-OH

Example

Alcohol

Amine

Aldehyde

Ketone

Carboxylic acid

Ethanol

Ethanamine

Ethanal

Acetone

Acetic acid

NameFamilyFunctionalgroup

CH3COCH2CH3

O-C-ORCarboxylic ester Ethyl acetate

O

O

O

O

NR