Derivatives (Fats)

Question 1

What are fats

Answer 1

Triesters of propane-1,2,3-triol (glycerol) and fatty acids

Question 2

Structure of Glycerol

Answer 2

H2C-OH
|
HC-OH
|
H2C-OH

Question 3

What is a Fatty Acid

Answer 3

Carboxylic Acids with long hydrocarbon chains

Question 4

What are the main fatty acids
And their formulas

Answer 4

Stearic Acid:
CH3(CH2)16COOH

Oleic Acid:
CH3(CH2)7CH=CH(CH2)7COOH
Z-Isomer C17H33COOH

Question 5

Composition if saturated fatty acids group attached to COOH

Answer 5

CnH2n+1

Fewer Hydrogens means Unsaturated

Question 6

How much mol of fatty acids can 1 mol glycerol react with

Answer 6

3mol Fatty Acids

Question 7

Glycerol + Stearic Acid

Answer 7

Glyceryl Tristearate + 3H2O

Question 8

When will a fat be an Oil

Answer 8

Contains a large proportion of unsaturated fatty acids
-more c=c weaker VdW forces
-more c=c lower melting point

Question 9

When will a fat be solid

Answer 9

More saturated fatty acids
Greater VdW between
Higher MP- Solid more likely

2 or more c=c - polyunsaturated

Question 10

Saturated fats in diet

Answer 10

Provide energy and insulation for body
High levels of low density lipoproteins can lead to coronary heart disease

Question 11

Unsaturated Fats in Diet

Answer 11

Increase high density lipoproteins levels - reduces risk of CHD

Precursor molecules for prostaglandins

Artificial trans/E unsaturated fats increase risk CHD

Question 12

Whats the effect pf multiple C=C

Answer 12

Multiple isomers

Each c=c can be E or Z

Question 13

Hydrogenation of Fats

Answer 13

Unsaturated fats react w/ Hydrogen in presence of finely divided nickel
180°C

Each C=C react w/ H2

1mol of fat react with x mol of H2
x= no. double bonds in fatty acid -achieve total saturation

Question 14

Hydrolysis of Fats

Answer 14

Saponification - based catalysed hydrolysis produces glycerol sodium and salt of FA (salt is a soap)

Acid catalysed gives glycerol and fatty acids
fat + h2o -> fatty acid + glycerol

Question 15

Transesterification

Answer 15

Swapping alkyl group in ester for a different alkyl group

Produce biodiesel and margarine

Question 16

Producing Biodiesel

Answer 16

Fats and oils react with methanol or ethanol to produce

Question 17

Biodiesel

Answer 17

Renewable fuel, similar to diesel, which is made from vegetable sources

Question 18

What is excess meth/ethanol used for in transesterification

Answer 18

Drive reaction to produce methyl esters
-glycerol in industries like cosmetics
-biodiesel mixed w/crude oil derivative to produce fuel

Question 19

What may occur after transesterification

Answer 19

Hydrogenation
Changes carboxylate groups within fat molecule or between molecules

Question 20

Types of transesterification

Answer 20

Carboxylate transferred to different carbon within fat molecule
INTRAMOLECULAR EXCHANGE

Carboxylate exchanged between fats
INTERMOLECULAR EXCHANGE

Question 21

Conditions of Transesterification

Answer 21

400K
Presence of alkali
glycerol
Catalyst (Sodium Methoxide or Sodium Ethoxide)

Produces higher RMM fat which after hydrogenation is a solid