Experiment#4: Isolation of Caffeine from Dried Tea Leaves

Question 1

A basic alkaloid from the Methylxanthine family. [1,3,7 - trimethylxanthine]

Answer 1

Caffeine

Question 2

In this compund’s pure form, it is odorless, white and fleecy.

Answer 2

Caffeine

Question 3

CAFFEINE
Caffeine is an alkaloid from what family exactly?

Answer 3

Methylxanthine

Question 4

CAFFEINE
Caffeine has the _____ ___ system, a framework that plays an important role in living systems.

Answer 4

Purine Ring System

Question 5

CAFFEINE
Caffeine is odorless, has a bitter taste and is ___ ____ in water.

Answer 5

highly soluble

Question 6

CAFFEINE
Medications designed to increase the amount of water and salt expelled from the body as urine. Caffeine acts as one of these.

Answer 6

Diuretics

Question 7

CAFFEINE
The stimulation of the heart resulting in a relaxation of the blood vessels.

Answer 7

Vasodilation

Question 8

CAFFEINE
A) Small doses of Caffeine (50-200 mg) and b) high doses of Caffeine (over 200 mg) result in what sort of effects on the human body?

Answer 8

A) Small doses can increase alertness and reduce drowsiness and fatigue.
B) Large doses can result in ”coffee nerves” (insomnia, restlesness, headaches and muscle tremors)

Question 9

COMPOSITION OF TEA LEAVES
The principal structural material of all plant cells. Tea leaves are primarily made up of this.

Answer 9

Cellulose

Question 10

COMPOSITION OF TEA LEAVES
Cellulose is insoluble in water, and thus can be separated from caffeine by…?

Answer 10

Hot Water Extraction

Question 11

TYPES OF TEA
This type of tea is produced through complete fermentation.

Answer 11

Black Tea

Question 12

TYPES OF TEA
Catechins, which make up 20% of black tea’s dry weight, is oxidized during fermentation to form _________ and ___________.

Answer 12

Theaflavins and Thearubigins

Question 13

TYPES OF TEA
These contribute to the sensory characteristic bright orange-red color of black tea.

Answer 13

Theaflavins

Question 14

COMPOSITION OF TEA LEAVES
Basic nitrogen containing compounds found in plants.

Answer 14

Alkaloids

Question 15

TYPES OF TEA
These leaves for this tea are heated immediately after harvesting, mechanically wound and compressed, and then dried to ensure the preservation of color.

Answer 15

Green Tea

Question 16

COMPOSITION OF TEA LEAVES
Astringent, bitter plant polyphenols that either bind and precipitate or shrink proteins that have acidic behavior.

Answer 16

Tannins

Question 17

COMPOSITION OF TEA LEAVES
Colored polyphenolic compounds of high molecular weight that thave acidic behavior and are water-soluble complex substances.

Answer 17

Tannins

Question 18

COMPOSITION OF TEA LEAVES
As much as __% by weight of the leaf material in tea plants consists of caffeine.

Answer 18

5%

Question 19

TYPES OF TEA
Also known as silver needle tea, this type of tea is a slightly-fermented type of tea.

Answer 19

White Tea

Question 20

TRUE or FALSE | COMPOSITION OF TEA LEAVES
Chlorogenic Acids are water soluble and have acidic properties.

Answer 20

TRUE

Question 21

TRUE or FALSE | COMPOSITION OF TEA LEAVES
Plant fats are soluble due to them having large hydrophilic groups present in their molecular structure.

Answer 21

FALSE. Plant fats are insoluble because they have large hydrophobic groups.

Question 22

The body’s secondary source of energy (the first being glucose). This contains a high percentage of saturated fatty acids.

Answer 22

Triacylglycerol [TAGS]

Question 23

COMPOSITION OF TEA LEAVES
Any type of colored substance produced by a plant.

Answer 23

Plant Pigments

Question 24

COMPOSITION OF TEA LEAVES
Based on the Schematic Procedure during the post-lab discussion, provide the 4 possible Insoluble Cellular Materials present in tea leaves.

Answer 24

• Cellulose
• Fats
• Plant Pigments
• Proteins

Question 25

**COMPOSITION OF TEA LEAVES** These are esters formed between caffeic and quinic acids, representing an abundant group of plant polyphenols in the human diet.

Answer 25

Chlorogenic Acids

Question 26

**COMPOSITION OF TEA LEAVES** A group of phenolic secondary metabolites produced by certain plant species and an important component of coffee.

Answer 26

Chlorogenic Acids

Question 27

**COMPOSITION OF TEA LEAVES** Biochemical substances that are **insoluble in water** and are soluble in nonpolar solvents.

Answer 27

Plant Fats (Lipids)

Question 28

Used to refer to lipids that are solid at room temperature.

Answer 28

Fats

Question 29

**COMPOSITION OF TEA LEAVES** **Chlorophylls**, **carotenoids** and **flavonoids** are examples of what?

Answer 29

Plant Pigments

Question 30

**PROCESS OF EXTRACTION** Provide the 7 characteristics of a Good Solvent for Liquid-Liquid Extraction.

Answer 30

- Low Boiling Point - Does not react with solute or other solvent - Not toxic - Not highly flammable - Immiscible with water - Inexpensive - Readily dissolves caffeine at room temperature

Question 31

**PROCESS OF EXTRACTION** This extraction process **allows soluble components to be removed from solids using a solvent.**

Answer 31

Solid-Liquid Extraction

Question 32

**PROCESS OF EXTRACTION** Based on the pdf lecture, what are the 2 possible applications of Solid-Liquid Extraction?

Answer 32

- Obtaining oil from oil seeds - Leeching of metal salts from ores

Question 33

**PROCESS OF EXTRACTION** What are the 2 components of tea leaves that are readily soluble in hot water and are separated from the tea leaves themselves during Solid-Liquid Extraction?

Answer 33

Caffeine and Tannins

Question 34

**PROCESS OF EXTRACTION** An extraction that used a liquid solvent to remove a liquid component from a liquid mixture.

Answer 34

Liquid-liquid Extraction

Question 35

**PROCESS OF EXTRACTION** This extraction is also known as **partitioning**.

Answer 35

Liquid-liquid Extraction

Question 36

**PROCESS OF EXTRACTION** Provide at least 2 applications of Liquid-Liquid extraction out of the 4 provided in the lecture.

Answer 36

- Removal of vitamins from aqueous solutions - Removal of aromatic compounds from crude oil fractions - In the chemical and mining industries - Downstream recovery of fermentation products

Question 37

**TRUE or FALSE | PROCESS OF EXTRACTION** In Liquid-Liquid Extraction, the aqueous layer will always be at the top and the organic layer will always be at the bottom.

Answer 37

**FALSE**. The determination of which solvent is at the top or bottom depends on the respective liquids’ **densities**.

Question 38

**TRUE or FALSE | PROCESS OF EXTRACTION** Dichloromethane is **denser** than water, meaning this organic layer will be found at the **top**.

Answer 38

**FALSE**. Denser liquids will always be found at the **bottom**.

Question 39

**PROCESS OF EXTRACTION** The ratio of the concentration of a compound in the two phases of a mixture of two immiscible solvents at equilibrium; dependent on temperature.

Answer 39

Distribution Coefficient

Question 40

**PROCESS OF EXTRACTION** ______ ______ is a drying agent, and will remove any water that may still be present in the mixture.

Answer 40

Sodium Sulfate

Question 41

**PROCESS OF EXTRACTION** Sodium sulfate, calcium chloride and magnesium sulfate are all examples of…?

Answer 41

Anhydrous Salts

Question 42

**PROCESS OF EXTRACTION** These have a high affinity for water and reverses back to its hydrous form after it has absorbed water.

Answer 42

Anhydrous Salts

Question 43

**PROCESS OF EXTRACTION** Crude caffeine can be purified by _________.

Answer 43

Sublimation

Question 44

**PROCESS OF EXTRACTION** Liquid-liquid Extraction is comprised of **2 steps**, namely?

Answer 44

- Mixing Phase - Phase Separation

Question 45

A procedure by which two liquids with different boiling points can be separated.

Answer 45

Distillation

Question 46

**PROCESS OF DISTILLATION** Distillation is a powerful technique for separating the component substance from a miscible fluid mixture by means of selective ________ and ________.

Answer 46

Selective Evaporation and Condensation