Sulfonic acid functionalized Precipitated Silica as efficient solid acid catalyst for acetylation reactions

Precipitated Silica has very high commercial significance in terms of ease of preparation, market volume, cost benefits and a wide range of industrial applications. The surface silanol groups of Precipitated Silica can be modified with reactive organic functional groups to achieve desired properties for specific applications, including catalysis. The objective of this study is to demonstrate sulfonic acid functionalized Precipitated Silica as a true heterogeneous catalyst in acetylation reaction, where the catalytic activity and desired product selectivity is a magnitude higher than industrial solid acid zeolite catalysts as well as similar catalysts reported in literature. To demonstrate sulfonic acid functionalized Precipitated Silica as a true heterogeneous catalyst in acetylation reaction, where the catalytic activity and desired product selectivity is a magnitude higher than industrial solid acid zeolite catalysts. A novel and cost-effective method for the functionalization of Precipitated Silica with sulfonic acid (–SO3H) is reported, where the silica nanoparticles are first functionalized in situ with a tetrasulfide organosilane, followed by oxidation of the tetrasulfide moiety to –SO3H groups, which are grafted to the surface silanol groups through covalent linkage. A novel and cost-effective method for functionalization of Precipitated Silica with sulfonic acid (–SO3H) is reported, where the silica nanoparticles are first functionalized in situ with a tetrasulfide organosilane, followed by oxidation of the tetrasulfide moiety to –SO3H groups, which are grafted to the surface silanol groups through covalent linkage. CHNS analyses and XPS prove successful functionalization of –SO3H group onto the nano silica surface. The resultant material acts as a solid acid catalyst and shows exceptional activity in the acetylation of benzyl alcohol and >99% selectivity towards the desired product benzyl acetate. The resultant material can also be recycled and reused several times. The following factors make sulfonic acid functionalized Precipitated Silica a new generation of solid acid catalyst; (i) higher atom economy, (ii) recyclability and reusability, and (iii) significant cost benefits with respect to industrial catalysts. The following factors make sulfonic acid functionalized Precipitated Silica a new generation of solid acid catalyst; (i) higher atom economy, (ii) recyclability and reusability, and (iii) significant cost benefits with respect to industrial catalysts. NA