US 11,702,345 B2
Silica suspensions
Frédéric Colbeau-Justin, Othis (FR); Marc-David Braida, Bry-sur-Marne (FR); and Mathilde Mignard, Bezons (FR)
Assigned to RHODIA OPERATIONS, Lyons (FR)
Appl. No. 16/772,149
Filed by RHODIA OPERATIONS, Aubervilliers (FR)
PCT Filed Dec. 20, 2018, PCT No. PCT/EP2018/086052
§ 371(c)(1), (2) Date Jun. 11, 2020,
PCT Pub. No. WO2019/129605, PCT Pub. Date Jul. 4, 2019.
Claims priority of application No. 17306943 (EP), filed on Dec. 27, 2017.
Prior Publication US 2021/0070618 A1, Mar. 11, 2021
Int. Cl. C01B 33/12 (2006.01); C08K 5/19 (2006.01); B82Y 40/00 (2011.01)
CPC C01B 33/12 (2013.01) [C08K 5/19 (2013.01); B82Y 40/00 (2013.01); C01P 2004/62 (2013.01); C01P 2004/64 (2013.01)] 10 Claims
 
1. A process for the preparation of a suspension of silica particles
said suspension comprising a water-immiscible polar organic liquid, at least one phase transfer agent, and silica particles having an average particle size of less than 400 nm, characterized in the organosilane moieties derived from compounds of formula (I):
R—Si(OR1)3  (I),
wherein R is —CH3 or CH═CH2 and each R1 is independently selected from the group consisting of —CH3 or —C2H5, are chemically bound to the silica,
said the process comprising:
(i) mixing a solution of the at least one phase transfer agent in a water-miscible organic liquid with a suspension in water of silica particles having an average particle size of less than 400 nm;
(ii) adding the water-immiscible polar organic liquid to the suspension obtained in step (i) to form a biphasic system comprising an aqueous phase and an organic phase containing the silica particles;
(iii) separating the aqueous phase from the organic phase containing the silica particles thus obtaining a suspension of silica particles in the water-immiscible polar organic liquid;
(iv) reacting the silica particles in the suspension obtained at the end of step (iii) with a compound selected from the group consisting of the compounds of formula (I) as previously defined.