Margarine, a substitute for butter, is manufactured in U.S.A, UK and other European countries in large quantities by the hydrogenation of vegetable oils and soft fats (Norman, 1902).
And India 'Vanaspati' or 'Vegetable ghee' was first introduced after the first Word War (1919) and it has found immense popularity because it resembles natural ghee in appearance.
It is made industrially by hydrogenation of vegetable oils such as groundnut oil, cottonseed oil, sesame oil, soyabin oil and sunflower 🌻 oil.
The hydrogenation is carried by passing hydrogen gas through the heated oil in the presence of metallic nickel as catalyst.
The nickel catalyst required for the process is obtained by mixing a nickel as catalyst. The nickel catalyst required for the process is obtained by mixing a nickel salt 🧂 (such as nickel formate or nickel carbonate) with unsaturated oil and then heating the mixture and passing hydrogen into it.
Thus the salt is reduced to finelly divided nickel dispersed in the oil and ready for use.
The hydrogenation of oil is actually carried in a 'hydrogenation tower' or 'converter'. It is a tall cylindrical steel vessel with cone-shaped fitted with a stirring device and also heating and cooling coils. The mixture of oil and nickel catalyst prepared as described above, is pumped into the converter. Here it is partially mixed by stirring and partially by the flow of hydrogen entering at the base through a perfor - ated pipe. Steam is passed through the heating coils, while the oil mix is continuously pumped to the top of the converter where it is sprayed back down the tower.
Since the heating is stopped as the reaction gets going and the temperature is maintained at about 200° by passing cooling water through the coil if nessary. The hardening the coils if necessary. The hardening of oil the coils takes place most readily and low pressure (30-35 psi). When Hardening has taken place to the required degree, the reaction is stopped by lowering the temperature to about by lowering the temperature to about 70°. The catalyst is filtered and the product is rebleached and deodorised under vacuum.
The Vanaspati so prepared has melting point 31 -37° and has the texture of ghee which would melt like ghee when placed on the tongue.
