Organic Chemistry: Unit 1 Test

Organic Chemistry

the study of all chemicals containing carbon

Ex) Natural gas, rubbing alcohol, Aspirin, Perfumes

Vitalism

• Concept of Organic Compounds before 1828

• Compounds came from living organisms

• Could not be made in a laboratory

• 'Vital Force' [God] was necessary to synthesis an organic compound

Wohler

• Disproved Vitalism

• Attempted to make ammonium cyanate by reacting ammonium chloride and silver cyanate reaction made UREA CON(NH2)2

Organic Compounds

• a type of compound with carbon atoms, nearly always bonded with each other.

• hydrogen atoms and a selected few: Phosphorus, oxygen, sulfur

Saturated Bonds

SINGLE BONDS

Unsaturated Bonds

Double or Triple Bonds

Hydrocarbons

• Made of only C and H

• Saturated hydrocarbons (SB) are the simplest forms

Cycoalkanes/Cycloalkenes

are hydrocarbons containing one or more carbon rings

Aromatic Hydrocarbons

AKA arenes, are hydrocarbons that have at least one benzene ring

Aliphatic

Carbons arranged in chains

Cyclic

carbons arranged in rings

Aromatic

Contain a benzene ring

Alkane

- only single bonds

CnH2n+2

Alkene

- one or more double bonds

CnH2n

Alkyne

- one or more triple bonds

CnH2n-2

Cyclic Hydrocarbon

• Hydrocarbon chains that form rings

• They can contain single, double, triple bonds within the ring structure

Example) Cholesterol & human hormones such as estrogen and testosterone

Isomers

Two or more compounds with the same formula but their respective atoms arranged differently in space

STRUCTURAL or STEREIOISOMER

Structural Isomers

Have the same molecular formula but they differ in their structural formulas

Stereioisomers

- have the same structural formulas but have different arrangements in space

GEOMETRICAL ISOMERS & OPTICAL ISOMERS

Geometric Isomers

• Occur in molecules where rotation around a bond is restricted

• Most often in DOUBLE BONDS

• Most common cases are asymmetric and non-cyclic alkenes

CIS & TRANS

Properties of Geometric Isomers

- Their chemical properties are similar but they physical properties are different

Boiling points are HIGHER in CIS isomers vs TRANS isomers

Optical Isomers

• present in all compounds that contain at least one asymmetric carbon atom

• an asymetric carbon atom has 4 different atoms or groups attached

Distinguishing Enantiomers

• Optical isomers can be distinguished by the way they interact with plane polarized light

• wedges do not superimpose (become mirror images)

Enantoimers

• May look identical, mirror images of each other.

How to distinguish Optical Isomers:

• One endaintomer will rotate polarized light to the right, the other to the left

Polarized Light

• Polarized light is light that has been passed through a polarizing prism or filter

• The light vibrates in a single plane

Properties of Optical Isomers

• Enantiomers generally have similar physical and chemical properties with optical isomers

• the chemical properties may be significantly different when the enantiomers interact with other optically active compounds

Benzene

• represented as 6 carbon rings with 3 double bonds

• many are pleasant smelling

• most common benzene ring (C6H6) is HIGHLY UNSATURATED (C=C)

• They do not undergo same reactions as alkenes and alkynes

• Planar and hexogonal

• the double bonds are delocalized and in constant movement

• benzene is usually stable and resists most reactions

Functional Groups

• Alkanes are relatively unreactive

• A site of reactivity in an organic compound is called the functional group

Organic Family

a group of organic compounds with common structural features that impart characteristic physical and chemical properties

Functional Group

A particular combination of atoms that contributes to the physical and chemical characteristics of a substance

Alkanes

• Only carbon and hydrogen

• only SINGLE bonds

• ane

Alkenes

• Only carbon and hydrogen

• Has a double bond

• ene

Alkyne

• only carbon and hydrogen

• has a triple bond

• yne

Haloalkanes

• have the general formula R-X R = Alkyl group (carbon chain) X = halogen

• Iodo - fluoro - chloro -bromo

Alcohols

• only ONE oxygen

• has OH group

• can be primary (1°,2°,3°) according to position of OH group

• named as an alkanol

• ol

Aldehydes

• ONE oxygen

• has a C=O

• C=O group is at the END of the carbon chain, next to ONE hydrogen

• al

Ketones

• ONE oxygen

• has a C=O group

• C=O group is not at the end of the carbon chain, it is next door to TWO carbons

• one

Esters

• TWO oxygens

• one oxygen is part of C=O bond, the other is next door, sandwiched between TWO carbons

• yl - oate

Carboxylic Acids

• Has 2 oxygens

• has OH and C=O groups on the SAME carbon atom

• this -COOH group has to be at the END of the carbon chain

• oic acid

Ethers

• ONE oxygen

• the Oxygen is sandwiched between two carbon atoms

• names end with -ether

• oxy - normal

Amide

• has NH2 and C=O group on the same carbon atom

• named as alkanamide

• amide

Amines

• Contain NITROGEN

• has -NH2 group

• Can be classified as (1°,2°,3°) according to the number of H connected to N

• named alkyl amine

• amine

Hydrocarbon Derivative

A hydrocarbon derivative is a carbon containing compound in which one hydrogen has been substituted for a different atom

1. compounds with the same functional groups often has similar PHYSICAL PROPERTIES

2. REACT chemically in similar ways

Water

IS POLAR

Physical Properties of Alcohols

Polarity: the -OH bond is VERY POLAR , however if the alkyl (carbon) chain is larger this over powers and is non-polar covalent becoming less miscible with water

Melting/Boiling Points: Usually high boiling points compared to alkanes ( with the same number of C's) due to H bonding between molecules

States: Liquids mostly (at room temperature) less than 12 C's long

Solubility: Small alcohols are miscible in water, but solubility decreases as size of the carbon chain increases

Hydrogen bonding: YES! With other alcohols and water

Uses of Aldehydes

• Perservatives (formaldehyde)

• Pest Control (Smaller aldehydes)

• Perfumes (used in aromatherapy oils)

Carboxylic Acids

- organic acids are characterized by the presence of a CARBOXYL functional group

Fact: Used in police dogs

Carboxylic Acids are Weak Acids

• found in citrus fruits, vinegar (acetic acid tritration)

• sour milk and yogurt contain lactic acid which is produced by bacteria

Physical Properties of Carboxylic Acids

Polarity: VERY POLAR due to both the carboxyl group C=O and the hydroxyl group -OH [H bonds]

Melting/Boiling Points: Because of the above properties, carboxylic acids have high boiling points

Hydrogen Bonding: Carboxylic acids can H- bond with each other, and in fact primarily exist of dimers (2 molecules held together by H- bonding)

INCREASE C chain, INCREASE boiling point
INCREASE C chain, SOLUBILITY decreases

Esters are?

Organic compounds characterized by their presence of carbonyl group bonded to an oxygen atom
- R-COO-R'

Ester Facts!

• occur naturally in plants

• responsible for odors of fruits (bananas, oranges, raspberries, strawberries)

• found in fats and oils

• perfumes are made of esters

Esterfication

The reaction of a carboxylic acid and alcohol in the presence of an acid catalyst to produce and ester.

The main chain of an ester comes from the carboxylic acid, while the alkyl group in an ester comes from the alcohol

Properties of Esters

Polarity: Like carboxylic acids, esters are POLAR molecules

Hydrogen Bonding: Esters do NOT have -OH bonds therefore CANNOT form H-bonds with other esters

Solubility in Water: Can accept H-bonds with water, small MW are soluble. Greater than 4 carbons are NOT soluble in water

Melting/Boiling Points: Because esters cannot form H-bonds (intermolecular), they have LOW boiling points and are usually volatile liquids at room temperature

Ether is?

An organic compound with 2 alkyl groups (the same or different) attached to a central oxygen atom

Properties of Ethers

Polarity: Less polar than alcohols. The bent shape around the oxygen in an ether means that the 2 C-O bonds do not counteract (dipoles do not cancel) each other. This C-O bond is less polar than the O-H bond in alcohols

Melting/Boiling Points: Alkanes

Nitrogen

• 4 most common atom in living systems

• important for DNA and RNA

• essential for the function of proteins

About Amines

• Organic derivatives of ammonia, and like ammonia, are BASIC

• Classified according to the number of carbon groups attached to nitrogen

Properties of Amines

Polarity: N is more electronegative than H, the N-H bond IS POLAR

Hydrogen Bonding: can occur between amines and water

Boiling/Melting Points: Primary and Secondary amines have higher boiling points than tertiary amines because tertiary amines CANNOT form H-bonds

Solubility: Small amines (6 or less C) ARE soluble in water

Amide is?

Products formed in a reaction between a carboxylic acid and an amine

contains carbonyl group ( from acid) and an amino group (from amine)

Amines can be prepared through a condensation reaction between a carboxylic acid and an amine

Properties of Amides

Polarity: the -NH2 is HIGHLY polar and can form H-bonds (Amides properties are very similar to carboxylic acids. C-N and N-H bonds are very polar)

Hydrogen Bonding: Can form strong hydrogen bonds

Solubility in Water: Most are solids at room temperature, simpler low carbon count amides are quite soluble in water

Melting/Boiling Points: VERY HIGH boiling/melting points than other hydrocarbons of the same carbon count

Polarity from MOST to LEAST

• Amide

• Carboxylic Acid

• Alcohol

• Ketone/Aldehyde

• Amine

• Ester

• Ether

• Alkane

Why are organic reactions important?

Organic Chemists can use one or more thousands of reactions to change one type of organic compounds into a different organic compound.

Main types of Organic Reactions

1. Addition

2. Substitution

3. Elimination

4. Oxidation

5. Reduction

6. Condensation

7. Hydrolysis

Addition Reactions

• Atoms added to a double or triple bond

• Alkene or Alkyne undergoing an addition reaction means breaking down the double or triple bond

TO RECOGNIZE: Two reactants make ONE product

Common atoms that can be added to an alkene and alkyne are H and OH (from water), H and X (where X=halogen)

Cataysts for Addition Reactions

1. Alkene + Hydrogen -----> Alkane

Pt or Pd, 500°C

2. Alkyne + Hydrogen -------> Alkene (limited amount of H) or Alkane (excess amount of H)

Pt or Pd, 500°C

3. Water ------> Alcohol

H2SO4

4. HF, HCl, HI, HBr -------> Halogenated alkane

No Catalyst

5. Halogen --------> Double Halogenated alkane

UV light

Addition Reactions Facts:

• symmetrical molecules with an asymmetrical molecule gives ONE product

• Two asymmetrical molecules react to give TWO products

(Major and minor by using Markovnikov's Rule)

"The H rich get H richer"

• Alkenes and Alkynes usually undergo addition reactions

Addition Reaction definition:

- A reaction in which atoms from a small molecule react with a double or triple bond in an organic molecule and become part of the molecule.

Elimination Reaction

• Atoms are removed from a molecule to form double bonds

• Reverse of addition

TO RECOGNIZE: One reactant breaks into two products

ALCOHOLS undergo elimination reactions in the presence of a strong acid (H2SO4)

HALOALKANES undergo elimination to produce an alkene when they react with a strong base (NaOCH2CH3)

• Isomers are commonly made (structural) and geometric (cis and trans)

Elimination Definition

- A reaction in which atoms or groups of atoms are removed from an organic molecule and a double bond is formed in the molecule

Substitution Reaction

• A hydrogen atom or functional group is replaced by a different functional group

TO RECOGNIZE: two compounds react to form two products

• Benzenes can ONLY undergo substitution reactions (FeBr3 catalyst)

ALCOHOLS and HALOALKANES commonly undergo substitution reactions with a molecule that contains a halogen (HCL, HBr...)

HALOALKANES can undergo substitution in the presence of an ion

Substitution Reaction Definition:

- an atom or small group replaces another atom or small group on the organic molecule

Characteristic Feature: Carbon atoms are bonded to the same number of atoms in the product as the reactant

Condensation Reaction Definition

- Two large molecules combine to form one larger molecule and a very small molecule (usually water)

Condensation Reaction: Esterfication

• two molecules combine to form a single, bigger molecule

• water is usually produced in the reaction

• Carboxylic acid and alcohol can CONDENSE to form an ESTER

Esterfication definition

- a special type of condensation reaction in which a carboxylic acid reacts with an alcohol to form an ESTER and WATER

Catalyst: H2SO4 + Heat

Amide Formation

• A carboxylic acid and amine can CONDENSE to form an AMIDE

• Condensation because WATER is produced

Hydrolysis

• water adds to a bond SPLITTING IT into two

• REVERSE of condensation

• water can add to an ester or amide bond

• Ester + water makes a carboxylic acid and alcohol

• Amide + water makes a carboxylic acid and amine

Hydrolysis Definition

- The compounds that are formed by condensation reactions can be broken down by hydrolysis

How can a chemist favor a hydrolysis reaction?

Increase the concentration of the reactants of hydrolysis (ester + water)

Oxidation & Reduction

• Change in the number of H or O atoms bonded to C

• Always occur together

• One reactant is OXIDIZED while the other is REDUCED

Oxidization

• Carbon atom forced more bonds to oxygen or less to hydrogen

• Example: formation of C=O bond

• Occurs in the presence of an oxidizing agent, O3

• Alcohol oxidation can form an aldehyde or a ketone

TWICE OXIDIZED: Primary alcohol ---> Aldehyde ----> carboxylic acid

Secondary alcohol ---> Ketone

Tertiary alcohol ---> no rxn

Oxidation Definition

A reaction in which a carbon atom forms more bonds to oxygen, O, or less bonds to hydrogen, H

Reduction Reactions

• Carbon atom forms fewer bonds to oxygen or more bonds to hydrogen

• aldehydes, ketones and carboxylic acids can be "reduced" to alcohols

• Alkenes and alkynes can be reduced to alkanes

• Occurs in the presence of reducing agents like H2

Reduction Reactions Definition

- A reaction in which a carbon atom forms fewer bonds to Oxygen, O, or more bonds to Hydrogen, H

***Going back down to its simplest form

Combustion Reaction

A type of reaction in which a compound reacts with oxygen to produce the oxides of elements that make up the compound

Unlimited Oxygen:

C3H6 + O2 ---> CO2 (g) + H2O (g) + energy

Limited Oxygen

C3H6 + O2 ---> C (g) + CO (g) + CO2 (g) + H2O (g) + energy

C : soot (black deposits)
CO : carbon monoxide, colorless, odorless, poisonous gas

Polymers

Macro-molecules formed by the covalent attachment of set of small molecules named monomers.

Polymers can be classified as...

1. man-made synthetic polymers: -synthesized in the laboratory

2. Biological polymers: -found in nature

synthetic polymers

nylon, ployethylene, polystyrene

Biological polymers

DNA, Proteins, carbohydrates

Hydrocarbons at room temperature

Gas

• Methane, Ethane, Propane, Butane

Liquid

• 5 to 19 carbon chain

Waxy

• 20 to 40 carbons

Plastic 40 or more carbons

What other properties change?

• Viscosity

• Hardness

• Toughness

• Flammability

Bonding:

• covalent

• Ionic (NaCl)

• Polar (H2O)

Addition Polymerization

when monomers with double bonds are added together through multiple addition reactions, without a net loss of atoms.

Mechanism for addition Polymerization

1. Initiation -The reaction starts with the decomposition of the peroxide.

2. Propagation -The resulting radicals add to molecules of chloroethene to make new radicals. As more chloroethene molecules add on to one at a time, the chain continues to grow

3. Termination

• occurs when, for example, any two radicals react with each other.

Molecular structures of polymers

Linear

• High density Polyethylene (HDPE), PVC, Nylon, Cotton

Branched

• Low density - Polyethylene (LDFE)

Cross-linked

• Rubber

Network

• Kevalar, Epoxy

Chain Length: 1000-2000

Low density Polyethylene (LDPE) - cross-linked

• Plastic wrap for food

• Plastic gloves

Chain Length: 4000-5000

Polyvinyl chloride (PVC)

• Vinyls

• PVC pipes

• More molar --> stronger bonding

Chain length: 10000-100000

High-Density Polyethylene (HDPE) - Chain-linked

• milk cartons

• garbage bags

• buckets

Chain length: 2-6 million

Ultra-high-molecular-weight polyethylene (UHMWPE)

• Helmet

• Gears

• Joint Replacement

(Biological Polymer)
Rubber Tree:

Sap:

• Sticky

• Viscous

• Gooey

Goodyear (Tires)

• Experiment

• Luck discovered ---> Vulcanization

Condensation Polymerization

Monomers are joined together by the formation of an ester or amide bond. 2 functional groups are needed.

• water is created as a side product

• Polyesters contain many esters (nylon is an amide bond)

• Nylon (polyamide) contains many amide bonds

Chain Length: 4000-8000

Polyethylene Terephthalate (PETE) "Polyester"

• clothing

• water bottles

Kevlar

• bulletproof vest

• strong network of covalent bonds and polar hydrogen bonds