title: Electrolyte-added one-pot synthesis for producing monodisperse, micrometer-sized silica particles up to 7 microm.
abstract: A facile one-pot synthesis to produce micrometer-sized silica particles with low polydispersity was examined in a semibatch process where an ethanol solution of tetraethyl orthosilicate (TEOS) was continuously supplied to another ethanol solution of water and ammonia containing an electrolyte of LiCl, NaCl, or KCl. Supply rates of the TEOS solution was ranged with the water and electrolyte concentrations, which indicated that the addition of KCl at a low water concentration was effective to increase size of silica particles in a micrometer range. Highly monodisperse silica particles with an average size of 6.6 microm were successfully produced at 3 mol/m(3) KCl and 5 kmol/m(3) water. The efficiency of KCl addition for producing the large particles is interpreted by the previously proposed nucleation and growth mechanism that expects rapid particle coagulation in early reaction stage for particles which have reduced surface potential by the adsorption of cations with a large ionic radius. It is confirmed from competitive growth reactions that the silica particle growth follows the reaction-limited mechanism even in the semibatch process.
authors.affiliation: Department of Chemical Engineering, Graduate School of Engineering, Tohoku University 6-6-07 Aoba, Aramaki-aza Aoba-ku, Sendai, 980-8579, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nakabayashi
authors.forename: Akira
authors.initials: A
authors.lastname: Yamada
authors.forename: Masahiro
authors.initials: M
authors.lastname: Noba
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Kobayashi
authors.forename: Mikio
authors.initials: M
authors.lastname: Konno
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nagao
mesh_terms: D000641:Ammonia / Q000737:chemistry; D004573:Electrolytes / Q000737:chemistry; D000431:Ethanol / Q000737:chemistry; D018021:Lithium Chloride / Q000737:chemistry*; D010316:Particle Size; D011189:Potassium Chloride / Q000737:chemistry*; D012821:Silanes / Q000737:chemistry; D012822:Silicon Dioxide / Q000138:chemical synthesis* / Q000737:chemistry; D012965:Sodium Chloride / Q000737:chemistry*; D012996:Solutions; D013499:Surface Properties; D014867:Water / Q000737:chemistry
chemical_list: D004573:Electrolytes; D012821:Silanes; D012996:Solutions; D014867:Water; D000431:Ethanol; C040733:tetraethoxysilane; D012965:Sodium Chloride; D011189:Potassium Chloride; D012822:Silicon Dioxide; D000641:Ammonia; D018021:Lithium Chloride