CHEM 156 Study Guide - Final Guide: Silicon Tetrachloride, Dispersity, Ammonium Hydroxide
Article by Werner Stober, Arthur Fink
Objective: controlling the growth of spherical silica particles of uniform size by
hydrolysis of alkyl silicates and subsequent condensation of silica acid in alcoholic
solutions. Ammonia used as morphological catalyst. Particle size in suspension
range from less than 0.5 micron to 2 micron in diameter.
Facilitate easy calibration procedures for analytical equipment
○
Simplify data reduction, evaluation, and interpretation of experiments
of physiochemical properties and physiopathological effects of colloids
and aerosols
○
No bias by size and shape distributions
○
Production of monodisperse suspensions of silica spheres in colloidal
size range will be of interest in the medical field because of its known
cytotoxicity and inhalation hazard
○
Formation of silica particles by reacting tetraethyl silicate in
alcoholic solution with water in presence of certain bases
▪
Experiments based on: silica particles can be produced by chemical
reaction of tetraesters of silicic acid (tetraalkyl silicates) with certain
solutions
○
It’s desirable to have homogeneous particles of uniform shape and size when
experimenting with colloidal suspensions of matter in form of hydrosols and
aerosols
•
Introduction:
methanol, ethanol, n-propanol, n-butanol as solvents
○
Tetraesters of silicic acid prepared by reacting silicon tetrachloride and
alcohol
○
Ammonia for catalyst
○
Reagents:
•
Pure alcohol or alcohol mixtures, saturated alcoholic ammonia solution,
ammonium hydroxide, and water mixed in in sealed containers in
desired concentrations of ammonia and water
○
Alkyl silicate added and flasks mounted in water bath under ultrasonic
vibration
○
Condensation reaction started within 10 mins -- increasing opalescence
of mixture starting 1-5 mins after adding tetraalkyl silicate
○
Transition to turbid white suspension
procedures:
Experimental:
Controlled Growth of Monodisperse Silica Spheres in the
Micron Size Range
Thursday, June 14, 2018
2:20 AM
Chem 156 Page 1
Document Summary
Controlled growth of monodisperse silica spheres in the. Objective: controlling the growth of spherical silica particles of uniform size by hydrolysis of alkyl silicates and subsequent condensation of silica acid in alcoholic solutions. Particle size in suspension range from less than 0. 5 micron to 2 micron in diameter. It"s desira(cid:271)le to ha(cid:448)e ho(cid:373)oge(cid:374)eous parti(cid:272)les of u(cid:374)ifor(cid:373) shape a(cid:374)d size (cid:449)he(cid:374) experimenting with colloidal suspensions of matter in form of hydrosols and aerosols. Simplify data reduction, evaluation, and interpretation of experiments of physiochemical properties and physiopathological effects of colloids and aerosols. Production of monodisperse suspensions of silica spheres in colloidal size range will be of interest in the medical field because of its known cytotoxicity and inhalation hazard. Experiments based on: silica particles can be produced by chemical reaction of tetraesters of silicic acid (tetraalkyl silicates) with certain solutions. Formation of silica particles by reacting tetraethyl silicate in alcoholic solution with water in presence of certain bases.
