Before use in oleochemical production, the oils and fats need to undergo several modifications. Achieving maximum performance for every key step in this process — hydrogenation, interesterification and purification — requires selection of the right compound for the task.

Hydrogenation with Nickel Catalysts

One such modification step is hydrogenation, ensuring the required properties for oleochemicals.

MONCAT nickel catalysts — supported reduced nickel catalysts embedded in pastilles of hydrogenated vegetable oil — allow for a smooth, rapid hydrogenation reaction. The process improves the oxidative stability of fats and oils for increased shelf-life and modifies the texture and melting properties for improved products, from chocolate to greases.

Nickel catalysts enable the full hydrogenation of triglycerides during the process and decrease unwanted trans fatty acids (TFAs), which are being reduced globally due to health concerns. Certain food products or ingredients derived from oleochemicals (e.g., margarine, fatty acids) that have undergone partial hydrogenation may contain TFAs, making for a limited process.

Evonik Catalysts boasts the unique ability to apply the required reagents for both full hydrogenation and interesterification.

Interesterification with Sodium Methylate Powder

Even more important due to the limitations of partial hydrogenation, interesterification modifies the physical properties of oil or fat blends by rearranging fatty acid groups within different triglycerides, creating specific oleochemicals with desired properties.

Alkoxides like sodium methylate are commonly used for this process and work by rapidly breaking the ester bonds to initiate the fatty acid exchange in-between the molecules. In powder form, they assure a minimal formation of unwanted methyl esters and avoid the formation of TFAs. Compounds such as sodium methylate powder may require expertise from partners, like Evonik, experienced in handling.

Sodium methylate powder also modifies the desired melting behavior of end products and assists with achieving the right spreadability and consistency.

Purification and Decolorization

One step remains to create an appealing final product. Apart from the right structure, excellent purity is required, and — depending on the final application — the product needs to be flawless in terms of color and odor. Optimized adsorbents are critical here.

Silica gel and alumina (CHROMATOCEL) are often used to separate impurities from oils and phospholipids. Granular alumina is particularly useful for removing polar or charged impurities from oils; DYNOCEL 600/900 boasts a larger particle size at higher flow rates. Bauxite (PUROCEL) is effective in the removal of impurities as well as improving color, odor and free fatty acids (FFA).

For those selling oleochemicals into quality sensitive industries (e.g., pharmaceuticals, nutraceuticals, cosmetics), silica gel and alumina can be used to remove a wide variety of impurities during purification and polishing steps.

Conclusion

New consumer and legislative challenges create the need for improved processes and products; a portfolio that combines the relevant technologies needed for this is particularly appealing. Evonik’s complete package solution allows for synergy between the intertwined steps of oleochemical production – hydrogenation, interesterification and purification. With its catalysts and technology, customers are provided the ability to improve efficiency, selectivity and performance throughout the oleochemical process, for products that meet the strictest specifications of their end markets in a cost-effective way.

Author: Suresh Parab, Global Head of Product Group OFC, Evonik Catalysts

Sponsored by Evonik