Effect of polyvinylpyrrolidone on mesoporous silica morphology and esterification of lauric acid with 1-butanol catalyzed by immobilized enzyme

Mesoporous silica materials with a range of morphology evolution, i.e., from curved rod-shaped mesoporous silica to straight rod-shaped mesoporous silica, were successfully prepared using polyvinylpyrrolidone (PVP) and triblock copolymer as dual template. The effects of PVP molecular weight and concentration on mesoporous silica structure parameters were studied. Results showed that surface area and pore volume continuously decreased with increased PVP molecular weight. Mesoporous silica prepared with PVP K30 also possessed larger pore diameter, interplanar spacing (d100), and cell parameter (a0) than that prepared with PVP K15 and PVP K90. In addition, with increased PVP concentration, d100 and a0 continuously decreased. The mechanism of morphology evolution caused by the change in PVP concentration was investigated. The conversion rate of lauric acid with 1-butanol catalyzed by immobilized Porcine pancreatic lipase (PPL) was also evaluated. Results showed that PPL immobilized on amino-functionalized straight rod-shaped mesoporous silica maintained 50% of its esterification conversion rate even after five cycles of use with a maximum conversion rate was about 90.15%. Curved rod-shaped mesoporous silica can be obtained at low and the highest PVP concentration, while straight rod-shaped mesoporous silica can be obtained at higher PVP concentration. [Display omitted] •Mesoporous silica with morphology evolution from CRMS to SRMS were prepared.•Effects of PVP molecular weight and concentration on silica morphology were studied.•A possible mechanism for the formation of morphology evolution SiO2 was proposed.•Esterification of lauric acid with 1-butanol catalyzed by immobilized PPL.