By J. Walker
Microspheres are small spherical particles, with diameters in the micrometer range (typically 1 μm to 1000 μm (1 mm)). Microspheres are sometimes referred to as spherical microparticles. In general microspheres are solid or hollow and do not have a fluid inside, as opposed to microcapsules.
Microspheres can be manufactured from various natural and synthetic materials. Glass microspheres, polymer microspheres, metal microspheres, and ceramic microspheres are commercially available. Solid and hollow microspheres vary widely in density and, therefore, are used for different applications. Hollow microspheres are typically used as additives to lower the density of a material. Solid microspheres have numerous applications depending on what material they are constructed of and what size they are.( 1)
The esterification reaction between glycerol and lauric acid was conducted in the presence of commercial Amberlyst IR-120 and synthesized silicotungstic acid (STA)/SBA-15 at 393, 413 and 433 K. The results indicated that STA/SBA-15 was more convenient than Amberlyst IR-120 by means of monoglyceride production. Higher selectivity to monoglyceride obtained in the presence of STA/SBA-15 was due to its mesoporous structure, which induced shape selectivity in favor of monoglyceride. Reaction experiments in the presence of recovered catalysts showed an increase of monoglyceride selectivity, which was due to adsorbed lauric acid inside the mesopores. The selectivity was shown to be altered towards monoglyceride by simply changing the feed ratio and applying washing procedure on the catalyst. Characterization studies conducted on recovered catalysts validated the preservation of catalyst …
- V Simsek, L Degirmenci, K Murtezaoglu , “Synthesis of a silicotungstic acid SBA-15 catalyst for selective monoglyceride production”, Reac Kinet Mech Cat (2016) 117:773–788.
- Veli ŞİMŞEK, Kırali MÜRTEZAOĞLU, “Investigation Of Lauric Acid Conversion With The STA Incorporated Heterogeneous Catalysts In Liquid Phase Reaction”, Bilecik Şeyh Edebali Üniversitesi Fen Bilimleri Dergisi (2019) 1: 1, 91 – 103
V Simsek, L Degirmenci, K Murtezaoglu, “Sustainable activity of hydrothermally synthesized mesoporous silicates in acetic acid esterification”, Turk J Chem (2015) 39, 683-696