Hardening of fats

Fett-hilrtung, /. hardening of fat(s). -harz, n. oleoresin. -harzreserve, /. (Calico) fat resip... 

The third important use of hydrogen is, as we have observed in a previous article, in the hardening of fats, by direct action in the presence of finely-divided metallic nickel. According to the method of Sabatier and Senderens certain fine chemicals are now made by the nickel method of hydrogenation, and this also is likely to find extended application in industry. 

A significant application of hydrogen with a large-scale technological importance is in the food industry the hardening of fats and oils by catalytic hydrogenation for the purpose of extended durability. The process takes place at pressures of 20 - 40 MPa and at temperatures of 200 - 400 °C. 

Hardening of fats is also a three phase catalytic hydrogenation. On nickel or palladium, saturation of the double bonds occurs simultaneously with cis-trans-isomerization and double bond migration. As shown by the example of Figure 13, all these reactions influence the melting point of the treated fat. This very delicate hydrogenation is operated batchwise in stirred tank reactors. Trickle-bed operation is very rare. 

Examples of multiphase reactors involving a liquid, a gas, and a solid catalyst are hardening of fat by hydrogenation and desulphurization of fuels. In a simpler case the solid substance may be inert and serves solely to increase the gas-hquid interface. The various three-phase reactors may be classified according to the mode of motion of the phases (Figure 4.10.12). 

Tacke, T., Wieland, S., and Panster, P., Hardening of fats and oils in supercritical CO2, Proc. of the 3rd Int. Symp. on High Pressure Chemical Engineering, Zurich, 1996. 

CY Tsang, WB Streett. Phase equilibria in the H2/CO2 system at temperatures from 220 to 290 K and pressures to 172 MPa. Chem Eng Sci 36 993-1000, 1981. T Tacke, S Wieland, P Panster. Hardening of fats and oils in supercritical CO2. In P Rudolf von Rohr, C Trepp, eds. Process Technology Proceedings. Vol. 12. High Pressure Chemical Engineering. Amsterdam Elsevier, 1996, pp 17-21. 

Hardening of Fats. Fats that contain a large proportion of saturated fatty acids (there is always a variety of fatty acids in a fat) have a higher melting point and are solid at room temperature, whereas those fats with a high content of unsaturated fatty acids are liquid or oily (the term oil denotes consistency and not a... 

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