Synthetic detergents came about during W.W.II because animal and vegetable oils were in short supply which led to a shortage of soap.
Scientists discovered that an acid similar to a fatty acid (which are found in animal fats and vegetable oils) could be made from petroleum chemicals reacted with sulphuric acid.
This compound was mixed with an alkali similar to lye and made a synthetic cleaning agent which was effective even in hard water.
Synthetic detergents soon replaced soap for cleaning and laundry purposes and are now found even in personal care products such as shampoo, foaming facial cleansers, cleansing bars, toothpaste and a proliferation of liquid soap substitute.
Most mass produced personal soaps in use today are made with an 80% tallow and 20% coconut oil formulation and are rapidly being replaced by synthetic detergents also known as 'soap free' cleansing bars.
For the past fifty years modern process engineering and chemistry has resulted in production rates of more than 50 tonnes of soap per hour making soap a relatively low cost common place commodity.
However, today's mass produced soap differs greatly from the soap of yesterday.