Improving the Stability and Efficiency of Dimeric Fatty Acids Production by Increasing the Brønsted Acidity and Basal Spacing of Montmorillonite.

Montmorillonite (MMT) is widely used as the catalyst in the commercial production of dimeric fatty acids (DAs). However, the dimerization activity of MMTs from different mineral sources is usually different, leading to unstable yield of DAs. In order to obtain a high and stable yield of DAs, the relationship between the dimerization activity and characteristics of MMT should be clarified. The characteristics of seven MMTs from different mineral sources, including the acidity (the type, strength, and amount of the acid sites), composition (interlayer cations, Si/Al ratio, water content, pH), and structure (basal spacing) are determined and correlated with their dimerization activity. Additionally, the relationship between dimerization activity and characteristics of MMT is quantified by nonlinear‐regression. It is found that the dimerization activity of MMT is mainly influenced by its Brønsted acidity and basal spacing. Stable DA yield of around 70% on MMT is obtained at the amount of weak Brønsted acid sites of more than 0.20 mmol g−1 and basal spacing of larger than 1.50 nm. Additionally, it is found that acid treatment is an effective method to adjust the Brønsted acidity and basal spacing of MMT. Practical Applications: The positive effect of Brønsted acid sites amount and basal spacing on the activity of MMT has practical value on the selection of highly efficient MMT catalyst for DA production. In addition, some MMT with poor activity can be activated by the acid treatment method mentioned in the paper. [ABSTRACT FROM AUTHOR]