Hydroxymethylsilanetriol – A Simple Analog of Silicic Acid

Abstract

Hydroxymethyltriethoxysilane and hydroxymethyltrimethoxysilane, precursors by hydrolysis to a simple analog of silicic acid, hydroxymethylsilanetriol, were prepared. Hydroxymethyltrialkoxysilanes undergo condensation to form silmethyleneoxide oligomers and dimeric 2,2,5,5-tetraalkoxy-2,5-disila-1,4-dioxanes. Hydroxymethylsilanetriol undergoes condensation reactions similar to silicic acid and readily forms organosilicate structures by sol-gel processing techniques which may be converted at relatively low temperatures to silicon dioxide. Hydroxmethylsilanetriol derived gels were subject to less stresscracking during drying than conventional tetraethoxysilane derived gels, suggesting that Si-O-C bond equilibration during drying provides a mechanism for stress-relief. In screening experiments, hydroxymethylsilanetriol appears to be a competitive inhibitor of the growth of the diatom C. fusiformis, a silicate dependent species, which produces silicate structures.

Preparation of hydroxyl group containing bridged organosilica membranes for water desalination

“…The weight loss around 100-300 °C was likely due to the condensation reaction of residual Si-OH groups in the gel powders [35]. For HMTES, the condensation of C-OH and Si-OH bonds would be also involved in this temperature range, which might be responsible for the greater weight loss of the HMTES gel [28]. The weight loss around 400-700 °C seemed to be due to the thermal decomposition of organic groups [35].The larger weight loss of the HMTES gel than that of the BTESE gel in this temperature range was likely due to the different composition of the gels.…”

“…The feed pressure of 1.0 MPa was applied with a plunger pump. Liquid permeance (L p ) and NaCl rejection (R)were calculated based on equations ( 1) and ( 2), respectively, where ΔP and Δπ, Jv, and C f and C p are, respectively, differences in applied pressure and osmotic pressure, permeate water flux, and NaCl concentrations of feed and permeate determined from their conductivities.Details of water permeability measurements are available in the literature [28].…”

“…6, and the data are summarized in Table 1 was also observed that the membrane was partly peeled off from the substrate during the measurement. As HMTES-gel was reported to be stable to water and not soluble even in cold sulphuric acid, softening of the membrane by partial hydrolysis seemed to be responsible for the mechanical damage (vide infra) [28]. The mixed membranes BT-HMx were also examined with respect to water desalination.…”

“…Usually, silica membranes that are prepared by calcination of silica sol-coated films are rather hydrophobic. The results clearly indicate that the post-treatment of HMTES-containing membranes with water offers a new convenient method to increase the hydrophilicity of the silica membranes.Although homo-and copolymerization of HMTES giving the polymer gels have been studied, their utilities as separation membranes and post-hydrolysis of the polymers tuning the hydrophilicity have not yet been reported to our knowledge [27][28][29][30]. Chart 1.Chemical structures of alkoxysilanes investigated in this study.…”

There are not enough data to conclude that Monomethylsilanetriol is safe

“…In fact, a recent study indicates that silanetriol can be seen as an analogue of silicic acid with a specific and potential therapeutic activity as it was found to inhibit the hydrolytic enzyme acetylcholinestearase [ 4 ]. In another recent study it was shown that the growth rate of the silicon dependent diatom C. fusiformis , was only 25–30% of the growth rate observed for silicic acid when hydroxymethylsilanetriol was used in the culture medium [ 5 ]. Analogues are frequently used in the development of new drugs but caution is certainly needed for the application in food.…”