Question

Contrast the reaction to form biodiesel with the reaction to form soap. Why do they form different products given that both reactions start out with a base and a fat or oil?

Answer 1

In the production of biodiesel & soap the starting material is same that is fatti acids or vegetable oil. Both the reaction also involves the base. But these bases are different in both cases & that is the key factor.

1) Production of biodiesel -

In the production of biodiesel, Vegetable oil is reacted with methanol or ethanol ( generally lower alcoholes as base). The reaction is called as Transesterification. The reaction is shown below.

In image attached below ( 1.)

2) Production of Soap -

The process of soap manufacturing is called as Saponification. In this reaction, Vegetable oil is reacted with base mainly sodium hydroxide to form soap. Scheme is depicted below. In image (2).