Use of chrysotile to produce highly dispersed K-doped MgO catalyst for biodiesel synthesis

•Chrysotile impregnated with K+ was used to produce a new basic heterogeneous catalyst.•The combination of chrysotile and K+ after calcination produces a safer material.•The material showed very good activity for biodiesel synthesis.

In this work, a new heterogeneous catalyst for the biodiesel synthesis was produced by the combination of chrysotile with KOH and thermal treatment. SEM, XRD, TG/DTA, BET, titration and CO2-TPD results suggest that chrysotile fibers [Mg3Si2O5(OH)4] impregnated with KOH decompose at 700 °C to produce safer sintered large particles containing a catalytically active K+ doped MgO dispersed phase. This K+/MgO phase showed surface basic sites with very good activity for the transesterification of soybean oil with methanol under different conditions. Control experiments suggest that K+ is not leached by methanol and the catalyst can be reused for several times.