Title : Catalytic hydrogenation of stearic acid to stearyl alcohol over cobalt silica catalysts
Abstract:
Conversion of basic oleo chemicals to fatty alcohols is a very important transformation as fatty alcohols are widely used in fragrances, detergents, emulsifiers, lubricants, health supplements and pharmaceuticals. In addition, fatty alcohol from petrochemicals is facing several challenges including depleting of the finite source of oil and gas, and many environmental problems such as climate change, air and water pollution that are associated with production, use and disposal of petrochemicals products. Fatty alcohol is commercially produced through the hydrogenation reaction using chromite-based catalysts. However, this process requires elevated temperatures (200-300o C) and pressures (100- 300 bar). Additionally, the use of chromite is associated with environmental problems.
In this study, Co/SiO2 catalysts with varied cobalt loading have been applied in the hydrogenation of stearic acid to produce stearyl alcohol. The influence of cobalt loading and catalytic properties on the activity and selectivity was studied by performing the reactions in a batch reactor at 300o C and 50 bar. Co/SiO2 was found to convert stearic acid to stearyl alcohol with high selectivity along with octadecanal, octadecane and heptadecane. Experiment results revealed that the cobalt loading influenced the activity of catalysts including the conversion, stearyl alcohol selectivity and reaction rate. The available metal area was observed to be the main reason for the increase of conversion and reaction rate enhancement. While the selectivity to stearyl alcohol was able to be maintained above 93% over cobalt loadings between 4-8 wt%. In addition, the study of turn over frequency over varied cobalt dispersion generated from different cobalt loading confirmed that hydrogenation of stearic acid over cobalt silica is structure insensitive.
Audience Take Away:
- Cobalt silica as an alternative catalyst for fatty alcohol production which successfully converted the stearic acid as a model compound to stearyl alcohol. This catalyst has addressed the challenge of current industrial catalyst in terms of mild reaction condition, economic point of view, and environmentally friendly.
- The preparation and the characterization of catalyst as well as the description of catalyst properties related to the result of stearic acid hydrogenation.
- The highlight of hydrogenation of stearic acid process including the conversion, product selectivity and other significant information linked to the reaction such as reaction order, turn over frequency, and catalyst structure independency.
