Students learn to describe the conditions under which saponification
can be performed in the school laboratory and compare these with industrial
preparation of soap.
The starting materials for most industrial soap manufacture are a little
different to those
used in the school laboratory.
In the school laboratory, it is usual to use highly refined materials such
as purified olive oil, purchased from the supermarket.
Industrially, the raw materials are used,
usually with some processing and purification before or
after the synthesis of the soap. (The impurities that occur in the
fats and oils used lead to dark stains in the soap and foul odours.)
The most common starting materials are:
- A fat obtained as a by-product of beef (and sometimes sheep) processing
and is the most common sort of animal fat used in soap manufacture.
The domestic beef and sheep market usually supplies all the tallow
required. The long chain length of the fats in tallow make the soap
feel greasy. Oils such as coconut oil are often blended with the tallow
to improve its performance.
- Coconut Oil
- Like most of the vegetable oils, coconut oil is usually imported
from south-east Asia (primarily Malaysia and the Philippines).
The oil is obtained from the dried fruit of the coconut palm tree, the
fruit having been dried wither in the sun or by burning the husks.
The oil is pressed out of the dried fruit.
- Palm Kernel Oil
- This oil is obtained from the nuts of the oil palm tree (Elaeis guineensis) and has similar
properties to Coconut oil.
- Palm Oil
- Derived from the fleshy fruit of the palm tree rather than the nut,
Palm oil has a longer chains than palm kernel oil. This gives it
properties more akin to Tallow than other vegetable oils.
Bartolo, R.G., Soap, in Encyclopedia of Chemical Technology, 4th ed,
J.I. Kroschwitz, Editor. 1993, Wiley Interscience. p. 297-326.]