To go from precursor to colloid, hydrolysis is the first essential step which requires water. In an anhydrous non-polar solvent, your precursor remains a precursor. You might end up with a few intermediate structures due to trace amounts of water, but at a very low yield. When you add an organic base or acid to this system, hydrolysis might form the hydrophilic intermediate which will then just precipitate. Again water or alcohol are necessary. From a chemical point of view, hydrolysis and condensation won’t happen. It‘s a different story when you want to silanize already synthesized silica. In that case, the dried silica powder will adsorb the trace amounts of water on their surface that cause the reaction to go forward and specifically at the desired location. The solvent will prevent bulk polymerisation of the silane molecules.

To go from precursor to colloid, hydrolysis is the first essential step which requires water. In an anhydrous non-polar solvent, your precursor remains a precursor. You might end up with a few intermediate structures due to trace amounts of water, but at a very low yield. When you add an organic base or acid to this system, hydrolysis might form the hydrophilic intermediate which will then just precipitate. Again water or alcohol are necessary. From a chemical point of view, hydrolysis and condensation won’t happen. It‘s a different story when you want to silanize already synthesized silica. In that case, the dried silica powder will adsorb the trace amounts of water on their surface that cause the reaction to go forward and specifically at the desired location. The solvent will prevent bulk polymerisation of the silane molecules.

I support Joeri's answer. Without water Nothing will happen. You might compare with our publiction in which we transfered water via vapor to silane bulk material.

Article Analysis of silanes and of siloxanes formation by Raman spectroscopy