Tetraethoxysilane-28, sometimes called TEOS-28, serves as a core material in the silicone industry and across advanced ceramics, coatings, and glass manufacturing. It appears as a colorless, clear liquid with a faint, sharp odor, flowing like a lightweight solvent and packing a punch when it comes to chemical reactivity. The molecular formula for Tetraethoxysilane is Si(OC2H5)4, and its structure forms a silicon atom bonded to four ethoxy groups. The density hovers around 0.93 g/cm3, making it lighter than water, a detail that matters in handling and process design. TEOS-28 stands out from similar silicates by its consistent purity, which becomes crucial for high-performance products, such as semiconductors or toughened glass, where impurities can lead to wild fluctuations in the finished product.
This clear, mobile liquid holds a boiling point close to 168°C, which gives it enough thermal stability for elevated-temperature reactions but still allows manageable distillation. Unlike some raw materials, TEOS-28 resists solidification under normal conditions. Still, exposure to moisture in the air slowly turns it into a sticky, colorless gel as it hydrolyzes and condenses to silica, which proves both a blessing for sol-gel synthesis and a challenge for storage. This property pushes users to seal storage vessels tightly or use inert gas blanketing to block water vapor access—small details mean fewer headaches later. Whether poured, pumped, or sprayed, TEOS-28 mixes freely into alcohols, ethers, and many organic solvents. It avoids strong acid or alkali environments since those speed up hydrolysis, clumping, and unwanted silica crusts. TEOS-28 typically appears in drums, smaller containers, or even bulk tankers for large-scale facilities. The HS Code for this compound falls under 2931900099, covering organosilicon compounds, an important detail for customs and regulatory paperwork.
As a silicon alkoxide, Tetraethoxysilane-28 steps up in reactions that build or modify silica-based networks. Through hydrolysis and condensation, TEOS-28 forms silicon dioxide as a gel, film, or powder, depending on the conditions chosen. This reaction sits at the backbone of sol-gel chemistry and drives innovation from basic glass coatings to advanced composite materials. The transformation lets users tailor microstructures, pore sizes, and even transparency. This kind of control in chemistry grows in value as industries chase lighter, stronger, and smarter materials. Reactivity, though, cuts both ways—when handled with wet hands or in open air, Tetraethoxysilane-28 can release ethanol, becoming slippery and carrying inhalation and flammability risks. In my experience around labs, even experienced chemists have accidentally left open containers, leading to crusty residues and unwanted messes that slow down work and drive up costs in wasted raw material.
Commercial versions of Tetraethoxysilane-28 always ship as a liquid—its volatility and hydrolytic behavior don’t lend themselves to storage as flakes, pearls, powder, or solid crystal. Any claims of TEOS-28 existing as a stable powder or pearl likely point to modified silicates, not pure tetraethoxysilane. Users who need a powder end up creating silica gels or powders as a downstream product, not as a raw material. Engineered silicates, like pre-hydrolyzed powders or pearls for specific needs, don’t behave or react quite like TEOS-28 itself. Direct handling of the clear liquid, with material transfer done in dry, well-ventilated settings, keeps the chemistry predictable and the plant running safely.
Working with chemicals like TEOS-28, safety has to come first. The liquid irritates skin, eyes, and airways, often more than newcomers expect. People often underestimate how quickly this colorless liquid penetrates gloves or causes redness, headaches, and mild dizziness—wearing goggles, nitrile gloves, and lab coats shouldn’t be optional. TEOS-28 is flammable, with a flash point around 50°C, so open flames or sparks turn routine handling into a risk for fires. In facilities I’ve visited, the difference between a minor incident and a week-long shutdown often boils down to proper storage and keeping the chemical away from ignition sources. Any vapor build-up in confined spaces, if left unchecked, brings the risk of explosion—good fume hoods, leak detection, and emergency planning become as important as the product’s technical performance.
Few chemicals offer such a direct path from liquid raw material to solid silica. This underpins innovation in fields from electronics—think silicon dioxide insulators—to building materials—where transparent, tough sealants need just the right precursor. Cost-saving and quality control depend on consistency, trust in supply chains, and practical experience in handling. For glass coatings or precision optics, TEOS-28 brings clarity where traditional silicates fall short. As demand for advanced materials rises, the routes opened up by TEOS-28 matter even more—not just for new products, but for lower emissions or reduced waste, since direct silica production via sol-gel often runs at lower temperatures than classic melting or sintering.
Handling chemicals with sharp reactivity calls for more than manual warnings—automation, spill prevention technology, and worker training round out the safety puzzle. In some factories, introducing sensors that alert for ethanol or silicon alkoxide leaks heads off trouble long before it grows. Packaging in small containers with tamper-evident seals, along with robust distribution partnerships, helps limit exposure risk across the supply chain. In research settings, shared stories of mistakes—like the time a graduate student cracked open a sticky, half-gelled container only for it to splatter across the hood—remind us that no safety protocol works if ignored in the rush to finish a synthesis or scale up a new process. Better labeling, active ventilation, team practice drills, and realistic information (not only technical data) keep people aware, alert, and safer during every stage of a project.
Pushing for greater safety and precision with TEOS-28, industry and regulatory bodies can tighten labeling standards, introduce certification of supply chains, and require full lifecycle tracking. Research groups—those outside large industrial plants—benefit from smaller, pre-mixed ampoules or cartridges, lowering spill and exposure risks. Manufacturers who invest in closed-loop systems, with easy decontamination and minimal transfer steps, see fewer lost batches and injuries. Broader education campaigns, targeting not just chemists but transporters and warehouse staff, shrink gaps in knowledge where many risks have slipped through in the past. Regulations increasingly demand safer handling and clear record-keeping—in my experience, these steps not only keep people safe but keep businesses competitive as well, since better practices cut down on fines, downtime, and damaged reputation.
Chemical Name: Tetraethoxysilane-28
Molecular Formula: Si(OC2H5)4
Molecular Weight: 208.33 g/mol
Appearance: Clear, colorless liquid
Density: Approx. 0.93 g/cm3 at 20°C
Boiling Point: ~168°C
HS Code: 2931900099 (Organosilicon compounds)
Solubility: Soluble in organic solvents, hydrolyzes in water
Hazard Statements: Flammable liquid and vapor, causes serious eye and skin irritation, harmful if inhaled
Storage Guidance: Use in dry, closed systems, keep away from heat, moisture, and sources of ignition
