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1. Literature Survey
Presentation by
Primary Information Services
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2. About Hydrophobic colloidal silica
• Synonyms Aerosil R972; silica dimethyl silylate; silica hydrophobica
colloidalis; silicic acid, silylated; silicon dioxide, silanat
• Hydrophobic colloidal silica is a silica derivative in which the surface of
the fumed silica has been modified by the addition of dimethyl silyl
groups. The chemical name and empirical formula for hydrophobic
colloidal silica are respectively Silica dimethyl silyate and Si02 (partly
alkylated for hydrophobation). The molecular weight is 60.08 g/mol.
Hydrophobic colloidal silica occurs as a light, fine, white or almost white
amorphous powder, not wettable by water.
• Functional Category : Anticaking agent; emulsion stabilizer; glidant;
suspending agent; thermal stabilizer; viscosity-increasing agent
• Regulatory Status: Approved for use in pharmaceuticals in Europe.
Approved by FDA and Europe for food contact articles. Included in
nonparenteral medicines (oral tablets; rectal suppositories) licensed in
the UK

3. Applications in Pharmaceutical
Formulation or Technology
Hydrophobic colloidal silica has nano-sized primary particles and
a large specific surface area,
(1) which provide desirable flow characteristics in dry powders
used in tableting(2–4) and capsule filling.(3) The hydrophobic
grades absorb less moisture(5) and may offer an advantage in
moisture-sensitive formulations.
(2) Hydrophobic colloidal silica is also used to thixotropically
control viscosity, to thicken and stabilize emulsions, or as a
suspending agent in gels and semisolid preparations.
Hydrophobic colloidal silica has a less pronounced effect on
solution viscosity but can thicken and stabilize the oil phase of
a water–oil emulsion.(3,5) With other ingredients of similar
refractive index, transparent gels may be formed.(5) Generally,
the uses and ranges of hydrophobic colloidal silica are similar
to the concentrations used of the standard hydrophilic
colloidal silicon dioxide

4. Patent US20030035888A1
Method for manufacturing hydrophobic colloidal silica
Abstract
The invention relates to a new method of manufacturing colloidal
silica which exhibits good dispersibility in an organic solvent, an
organic resin, a paint containing an organic solvent or resin, or the
like, is stable for a long period of time in a medium containing a
hydrophobic organic solvent as a major component, and has a low
metal ion impurity content under mild conditions.
The new method comprises the steps of taking a colloidal silica
dispersed in an aqueous dispersant; replacing a substantial
amount of the aqueous dispersant with one or more hydrophilic
organic solvent(s); preparing hydrophobic colloidal silica by
reacting the colloidal silica with an hydrophobizing agent; and
finally replacing the liquid phase of the dispersion comprising the
organic hydrophilic solvent with one or more hydrophobic organic
solvent(s) to obtain a hydrophobic colloidal silica dispersed in a
hydrophobic organic solvent.

5. Silica dimethyl silylate cas 68611-44-9

6. Remember…
Safety First!
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7. AMPRO
Product Information

8. Super
hydrophobic
coatings
based on colloid silica and fluoropolymer

9. Database

10. Questions? – about Literature Survey
mailto:primaryinfo@gmail.com
Silica dimethyl silylate, it is large specific surface area, which provide desirable flow
characteristics in dry powders used in tableting and capsule filling. The hydrophobic
grades absorb less moisture and may offer an advantage in moisture-sensitive
formulations.
Silica dimethyl silylate is also used to thixotropically control viscosity, to thicken and
stabilize emulsions, or as a suspending agent in gels and semisolid preparations.
Hydrophobic colloidal silica has a less pronounced effect on solution viscosity but can
thicken and stabilize the oil phase of a water–oil emulsion. With other ingredients of
similar refractive index, transparent gels may be formed. Generally, the uses and
ranges of hydrophobic colloidal silica are similar to the concentrations used of the
standard hydrophilic colloidal silicon dioxide.