The Saponification of Lipids

Introduction

This practical aims to use 5 experiments in order to calculate the iodination and saponification of a specific lipid. Saponification is the process of breaking down a neutral fat into glycerol and fatty acids by treatment with alkali. The products of this reaction are glycerol and fatty acid salts. The saponification value is the number of mg of KOH that is needed to saponify 1 g of the lipid. This value relies on the molecular mass of the lipid, and the molecular mass of the fatty acids. The molecular mass of the fatty acids are referred R1,R 2, R3 in the lipid and become higher as the molecular mass of the lipid increases. The iodine number is the number of grams of iodine (I2) that is needed to saturate 100g of lipid. This number shows how saturated a lipid is. However, this is also influenced by the molecular mass of the lipid. It is for this reason that the saponification value of the lipid must also be determined in order to calculate the molecular mass, the number of double bonds in the lipid (triacyl glycerol or TAG), and the average molecular mass of the fatty acids it contains and the number of carbon atoms in the fatty acids.

Lipids are organic compounds formed mainly from alcohol and fatty acids combined together by an ester. A compound can either be a mono-, di- or triacyl glycerol depending on the number of fatty acid molecules that form esters with glycerol. Lipids are sparingly soluble meaning they are not soluble in water. They are either hydrophobic (nonpolar) or amphipathic (containing both nonpolar and polar regions).

Results

Table 1: Titration values for Experiment 1

Flask | Volume Na2S2O3 (mL) |

1 | 7.2 |

2 | 7.1 |

Average: | 7.15 |

KMnO4 concentration (M) |

0.0198 |

Table 2: Mass lipid and titration value for Experiment 2

Lipid no. | Mass lipid weighed |

C1 | 0.274 |

Volume Na2S2O3 (mL) |

11.9 |

Table 3: Titration value for Experiment 3

Volume Na2S2O3 (mL) |

29.85 |

Table 4 mass lipid...