N-Trimethoxyoctylsilane first entered the chemical scene in the mid-20th century, right as industries began to demand better ways to attach organics to inorganics. This compound rode the early wave of organosilicon chemistry, where the challenge was always about blending oil-loving surfaces with water-based materials. Early manufacturers found that using silanes like these on glass kept coatings from peeling and stopped moisture from getting into the seams. Innovations snowballed as fiber optics, paints, and rubbers relied more on durable bonds certain silanes could offer. Over the decades, new assessment and synthesis methods polished up the production process. Many who have worked through those decades in coatings and plastics can remember the difficult, sticky substances before functional silanes hit the market. We take lasting paint adhesion or water-bouncing tiles for granted in homes and cars today, but each represents progress fueled by compounds like this one.
N-Trimethoxyoctylsilane, often called octyltrimethoxysilane, shows up clear and colorless, with a faint but distinctive organic odor that can linger in a lab. A classic organosilicon compound, it features one long octyl chain paired with three highly reactive methoxy groups hooked to the silicon atom. The result gives chemists and manufacturers a versatile tool for crafting water barriers, improving grip between dissimilar materials, and engineering specialty treatments. Technologists and bench chemists alike value the balance between the hydrophobic (water-repelling) and reactive parts of this molecule. Each bottle holds the promise of turning hard, breakable glass into a material that fights off fog, or a simple stone surface into a nearly self-cleaning masterpiece. In the competitive world of specialty chemicals, this isn’t just another additive; it bridges the divide between brittle minerals and grease-loving polymers.
Pour a small amount of N-Trimethoxyoctylsilane, and you’ll notice its thin and runny liquid form, floating atop water thanks to a density close to 0.94 g/cm³. The molecular weight lands right around 236 g/mol. It boils just above 200°C, making it stable under typical room or processing conditions, though it releases methanol vapors when exposed to moisture or strong heat. That distinct smell sometimes brings a headache in poorly ventilated labs—the result of slow hydrolysis breaking off methoxy groups. Its octyl group brings a charming oil-like slipperiness, which accounts for the moisture resistance in treated surfaces. Mix it with water, and it turns cloudy fast, kicking off a hydrolysis reaction that swaps those methoxy groups with hydroxyl, opening possibilities for further chemical linking.
Labels on drums or bottles show names like Octyltrimethoxysilane, CAS 3069-40-7, and sometimes trade labels from silane suppliers. Purity hits at least 97% for most technical applications, with moisture content sitting low—sometimes even below 0.1%—to avoid premature silanol formation during storage. The best suppliers include gas chromatography purity readouts and mention safe storage in cool, dry atmospheres, far from acids or water sources. SDS documentation underscores its flammability, promoting safe handling away from sparks and flames. Most quality programs run extra GC/MS checks to catch trace byproducts, while top labs routinely compare fresh and stored lots for fading or water pick-up because even slight contamination can spoil a whole coating batch on the line.
The road to octyltrimethoxysilane runs through a reaction between octyltrichlorosilane and methanol, in the presence of an acid scavenger. Chlorosilanes get handled with care, since their byproduct (HCl gas) stings eyes and corrodes steel pipes. Workers in specialty chemical plants have to weigh temperature control against reactivity, since overheating leads to runaway methanol vapor. Properly buffered methanolic solutions keep things under control, and the crude silane gets stripped of excess alcohol and acid before storage. Every plant produces its own quirks in yield and color, dependent on reactor material and local water purity—old-timers know which batches give purer material by nose alone. The process relies less on complex machinery, more on precision, patience, and respect for the volatility of the chemicals involved.
What makes this silane a workhorse lies in its willingness to react—usually, it’s the methoxy groups that do the heavy lifting. Upon exposure to water, they hydrolyze, generating methanol and a trio of silanol groups that eagerly hunt for glass, stone, or metal-oxide surfaces. There, they bond to form strong Si-O-metal links, sticking organic coatings tightly to brittle mineral backgrounds. Chemists also tweak the octyl chain—sometimes trading it for slightly longer or shorter alkyls—or swap out other functional groups to adjust slipperiness, flexibility, or chemical resistance. A silane like this sees further modification for tailored reactivity in advanced adhesives and even nanomaterial functionalization. Experienced lab hands often experiment with catalysts and alcohol mixtures to amplify reactivity or stretch the shelf life of opened containers. Moisture is always the enemy during storage; a single leaky bottle shortens a silane’s working life.
You might flip through catalogs or regulatory lists and find this compound under names such as Octyltrimethoxysilane, n-Octyltrimethoxysilane, Trimethoxyoctylsilane, or the straightforward CAS 3069-40-7. Major chemical producers like Evonik, Gelest, and Wacker sell it under their in-house trade names, tossing in branding for cross-market applications from waterproof textiles to anti-graffiti sealers. Buyers rely on these names because product quality often follows the supplier’s track record as much as the label, especially where batch consistency affects whole production runs. Anyone who’s run afoul of mismatched synonyms in a multi-language safety document knows the trouble caused by unclear naming.
Working with N-Trimethoxyoctylsilane takes a steady hand and clear protocols. Spilled material burns easily, so open flames and hot surfaces must stay clear. Gloves, goggles, and lab coats are non-negotiable—with methanol released during hydrolysis, inhalation poses real health threats. Industrial settings use local exhaust and vapor containment to minimize direct human exposure and environmental releases. Emergency protocols for spills and fires build on practical experience—quick neutralization with absorbent pads, followed by careful disposal. Operators follow strict training, reviewing MSDS sheets and incident drills, since hurried or poorly supervised handling once led to preventable fire incidents. Quality control teams often sample finished goods for residual silanes to ensure safety in products such as food packaging or children’s toys.
Everyday, surfaces from bathroom tiles to fiber-optic cables carry a layer of this silane. In construction, workers spray it on masonry and glass to block out water, extending building life through harsh seasons. Paint chemists apply it to automotive coatings to hold shine and let rain roll right off. In electronics, even a slight hydrophobic boost in circuit boards can fend off mishaps from condensation or accidental spills—something I once saw save an entire product line after a factory roof leak. Rubber gaskets in car engines last longer after silane treatment, since this toughens the material and fends off oil or coolant. Textile makers dip synthetic fabrics in dilute solutions, giving rain jackets or spill-resistant sofas a real fighting chance against stains. Researchers in biomedical fields coat medical devices with it for better blood compatibility or infection resistance.
Research teams persistently try to expand the boundaries of what N-Trimethoxyoctylsilane can do, juggling new methods that promise greener synthesis or more potent surface properties. Academic labs experiment on mixing this silane with others, chasing improved adhesion or longer-lasting antimicrobial features. Companies with a foot in semiconductors and nanotech find interest in manipulating surface energies for smaller, more powerful devices. Collaborative research initiatives often pop up between universities and leading silane suppliers, sometimes producing papers on durability tests or field trials for self-cleaning windows. Years of bench chemistry have also shown that changing the solvent, tweaking curing temperatures, or blending with novel nanoparticles drives modest gains in repellency and lifespan. Advances in computational modeling help researchers predict which new derivatives offer the best cost-performance balance.
Earlier toxicity studies flagged N-Trimethoxyoctylsilane for its methanol release on decomposition or hydrolysis. Methanol, as most process chemists and toxicologists know, can harm the nervous system with enough exposure, which drives the push for well-engineered process ventilation and training. Direct skin contact sometimes brings irritation, while the vapor irritates eyes and lungs. In chronic tests on lab animals, researchers track for organ-weight changes and behavioral shifts, though typical industrial exposures stay well below danger zones if handled smartly. Down-the-drain disposal or landfill dumping remains a real concern, as minor water contamination might still affect local ecosystems. Recent European REACH registration classified it with specific risk phrases, even as industry groups lobby for realistic exposure limits based on existing use conditions.
As greater demands for greener, more robust materials drive market change, N-Trimethoxyoctylsilane finds itself central in next-generation surface engineering. With climate shifts raising the stakes for moisture control and durability, more industries—from personal electronics to transportation infrastructure—lean on such compounds for performance. Efficiency in production continues to sharpen, with biotechnology and process intensification offering chances to slash waste. Growing regulatory oversight and customer wariness about chemical residues place new demands on suppliers, nudging them toward safer, cleaner silane formulations. Future research might produce bio-based feedstocks or higher-function analogs that leave fewer traces behind in soil and water. My years in research and quality control have shown that progress owes much to collaboration: chemists, production managers, and environmental scientists sit together more often now, shaping silane technology for a world that expects more from every sealed crack and protected chip.
N-Trimethoxyoctylsilane doesn’t show up on most shopping lists or everyday conversations, but it quietly supports much that keeps modern life humming along. In the backrooms of manufacturing, this compound goes to work where few notice. You can find it behind the water repellency of your phone's glass screen, the long-lasting finish on treated woods, and the tough, flexible coatings on concrete. Standing out among silanes for its effectiveness, N-Trimethoxyoctylsilane has built a loyal base in industries that value durable surfaces and fewer failures.
Back in my early days working for an architectural coatings manufacturer, I watched as new chemistries made old problems seem small. Walls stopped staining as fast. Sidewalks roughed it out against rain for years instead of months. In those improvements, that clear, almost oily liquid played an outsized role.
This happens because N-Trimethoxyoctylsilane reaches deep into porous surfaces like concrete, glass, and stone. Its long carbon chain lets the treated surface push away water. Mold loses its grip. Freeze-thaw damage and salt stains slow down. It stands as a shield against spills and stains that used to send property managers scrambling.
You also see N-Trimethoxyoctylsilane in the world of plastics and fiber-reinforced materials. Picture a situation: fiberglass resin that doesn’t want to play nice with glass fibers, causing the whole material to weaken and fray. Adding this silane smooths that relationship, locking resin and fiber together. The boat hull, the wind turbine blade, or the underground pipe comes out stronger because tiny molecules did their part at the interface.
Manufacturers trust this approach because better bonding means tighter, longer-lasting finished products. That pays for itself in fewer repairs and less waste, both of which speak to sustainability in industrial practice.
Looking at construction, green buildings start with how they last. Hydrophobic surface treatment saves repair bills and cuts back on material waste. In some European cities, where old stone buildings face constant battlegrounds with moisture, silane treatments changed the preservation game. I walked through historic sites where laser-cleaned facades looked nearly new despite wet, wintry weather, and local experts pointed to this silane compound as the reason.
Not everything comes without risk. N-Trimethoxyoctylsilane, much like similar chemicals, needs careful handling. Skin and eye protection, proper ventilation, and correct waste management give the compound a solid safety record in well-run shops. Regulatory agencies such as OSHA and European REACH set tight rules to guide employers. It’s not perfect, but teams paying attention can keep exposures below trouble levels.
Big cities keep growing, and infrastructure ages fast. Engineers turn to N-Trimethoxyoctylsilane as one building block among many for durable, low-maintenance materials. Researchers keep testing less hazardous alternatives and improved application methods, which could open doors for wider, safer use.
There is a patchwork of solutions—better training for workers, tighter recycling of chemical containers, careful attention to runoff in rainstorms—to keep the benefits flowing without creating bigger problems downstream. Lessons from the field prove this silane compound won’t be leaving manufacturer’s shelves or preservation projects any time soon.
N-Trimethoxyoctylsilane hits the shelf as a colorless, flammable liquid widely valued in coatings and adhesives. Its chemistry packs a punch—expose it to air and moisture, and those methoxy groups break down, releasing methanol, which can bring its own hazards. Over the years I’ve worked with specialty chemicals, keeping these organosilanes in check has meant paying attention to more than a printed data sheet. You pick up early on that one careless shelf or wrong label can mean difficult cleanup, real safety issues, or a ruined batch.
The most important thing: keep N-Trimethoxyoctylsilane away from water. This compound reacts fast—humidity starts breaking it down, and that can wreck its performance or create skin-irritant byproducts. I’ve seen garages and labs stash containers right under leaky pipes or next to humid windows—bad idea. Experts recommend a dry, well-ventilated room with steady climate control. Most suppliers say 2°C to 8°C, but in reality, I aim for a stable spot below room temperature, away from any chance of condensation.
Flammability is a constant concern. If the vapor builds up in a closed-off room with faulty ventilation, sparks from simple static or a light switch can spell disaster. The flash point hovers around 76°C, so a hot storeroom isn’t just unwise—it’s unsafe. Explosion-proof lighting and grounded storage racks help cut down on these risks. Never store big drums of this on upper shelves or close to oxidizers, acids, or bases. I’d rather see a smaller, clearly labeled drum on a metal spill tray than something stacked precariously in a broom closet.
In the field, the condition of the cap and the label often tells the real story. Oxygen and moisture sneak in fast if the seal isn’t tight. Over time, I’ve learned to look for shrink wrap or tamper-proof closures—not because I doubt the supplier, but because the slightest crack or tear means that product could be compromised. Labels with the correct hazard symbols and expiration dates are not optional—mislabeling once led to an unnecessary evacuation at a plant I visited. Regulatory compliance demands tight records, but for any owner or manager, it means peace of mind.
Spills do happen. I remember one morning, opening a poorly stacked pallet and finding a sticky puddle—cleanup required full PPE, and local air monitoring to ensure the low-level vapors didn’t accumulate to unsafe limits. Best practice: keep absorbents and spill containment supplies right alongside storage, and train staff on proper response. Specialized venting caps can prevent pressure build-up in containers, cutting down on accidental leaks in hot weather.
Access control makes a big difference. Untrained hands reaching for this compound can result in accidents or wasted inventory. Inventory checks and restricted access to storage areas are more than good housekeeping—they help ensure only those with the right training work with the chemical. In my experience, a shared logbook—filled in with every withdrawal or return—keeps surprises to a minimum.
Outdated or compromised N-Trimethoxyoctylsilane belongs in hazardous waste, never down the drain. Municipal waste streams aren’t equipped for silicon-organic leftovers. Proper disposal companies track these chemicals from pickup to destruction, closing the loop. Every workplace, from small university labs to large manufacturing outfits, bears the responsibility to their community to follow these rules to the letter.
N-Trimethoxyoctylsilane turns up a lot across industrial settings. It helps keep surfaces dry, prevents corrosion, and makes paints stick better. Folks in construction and manufacturing appreciate the protection it gives to concrete, glass, and metal. Much of the boost comes from the water-repelling barrier formed after it bonds with surfaces.
Working with this chemical in liquid form brings certain risks. Skin contact doesn't end with simple irritation—some workers have developed allergic reactions, redness, or blisters after repeated handling. Inhalation of vapors or mist, especially in tight indoor rooms, can leave people coughing or struggling with headaches. Industry safety groups like NIOSH and OSHA put out guidance on safe exposure because of these kinds of health effects. Wearing gloves, goggles, and masks makes a real difference in dodging trouble, so training in safe handling pays off fast.
Any time a substance gets used on a large scale, there’s concern about leftovers in the environment. N-Trimethoxyoctylsilane reacts with air and moisture, breaking down to release methanol. Methanol itself creates headaches for aquatic life and can disrupt the balance in water systems. Once the silane bonds with surfaces, it holds tight, which limits the danger of runoff compared to many solvents or coatings. Still, spills and improper disposal could cause issues—so waste management rules really matter. Both the European Chemicals Agency and the US EPA have flagged silane-based chemicals for close review due to potential harm if not handled responsibly.
Anyone who’s worn a paint mask or spent an afternoon around chemical sealers knows that fumes linger. People in construction told me about stinging eyes from poor ventilation during application. Even short jobs can spark headaches or—not uncommonly—a sore throat. For folks with asthma or chemical sensitivities, exposure can mean bigger trouble. From experience, just cracking open windows or running a fan usually falls short in confined areas. Relying on manufacturer’s safety sheets and gear can’t be optional, not just in big factories but on job sites and workshops, too.
Attention to detail makes all the difference in managing chemicals like this. Limiting spills, containing waste, and sticking to best practices for ventilation are more than formalities; they're essential steps to prevent long-term problems. Substitutes exist for some jobs—a few companies switched to water-based alternatives where possible, cutting down the risk both for workers and the planet. Regulators also encourage clear labeling and training so even a rookie understands the stakes before uncapping a container.
With any specialty chemical, staying informed is probably the best defense. Industry can’t always eliminate risk, but cutting corners can turn a bad day into a major health scare. From talking to workers and seeing real use in the field, I’ve learned that experience plus a respect for the risks sets the stage for safer outcomes. Nobody enjoys wearing extra layers of protection in hot weather or paying for disposal, but the payoff comes in fewer injuries and a smaller dent on local ecosystems. Learning from the past and building better habits does more for worker safety and clean water than any label on a drum ever could.
N-Trimethoxyoctylsilane is used in laboratories and industrial applications for its ability to modify surfaces and repel water. Most people outside of the coatings or plastics industries probably never hear about it, but those in research, manufacturing, or processing do. What matters most is understanding what you're working with. This chemical doesn’t scream for attention like some notorious lab hazards, but it deserves respect. Even the calmest liquids can cause trouble. It can irritate your eyes, nose, and skin, and it releases methanol during hydrolysis — a fact that anyone who’s ever caught a whiff knows is nothing to mess with.
Years ago in a university lab, I watched a seasoned technician remind a new intern to put on splash goggles, gloves, and a lab coat before handling the bottle. The new guy thought it was overkill, since the liquid didn’t seem volatile. Minutes later, a drop landed on his sleeve, followed by a hurried trip to the eyewash and a lot of muttering about never skipping steps again. There’s really no substitute for proper gear. Gloves made of nitrile, eye protection with full side coverage, and a long-sleeved barrier keep you out of the uncomfortable side of chemical work.
Using N-Trimethoxyoctylsilane requires a decent ventilation setup. I remember measuring vapor levels in an old lab where the fume hood fan had died — after half an hour, nobody wanted to breathe without a respirator. Methanol release builds up quickly. Always check fans and exhaust before opening containers. If the equipment feels iffy or alarms sound wrong, pause until you’re sure it’s clear to continue. The risk of trusting that everything “should be fine” isn’t worth it.
This compound reacts with water and humid air. I learned not to leave containers open for more than a moment. Tightly capped bottles in a cool, dry spot save a lot of money and worry. Silica gel in your chemical storage area doesn’t hurt. Most spills I saw happened because someone rushed — always seal bottles before even jotting down notes.
In one instance, a small spill on a bench turned sticky fast and started eating at a plastic tray. The right approach means grabbing the right absorbent and avoiding water-based cleaners. Sand, clay, or a dedicated solvent-based absorbent works best. Place rags or wipes in a closed metal waste can. These wastes need special disposal — skip the sink or trash chute. Find out your facility’s rules, or call the safety officer. A five-minute call beats an afternoon filling out incident paperwork.
People sometimes forget protocols if they haven't seen accidents, but vigilance pays off. Training matters just as much as the best set of gloves. In my experience, culture changes when people talk about little errors and close calls, not just big disasters. Set a clear routine, and keep open conversations about “what could go wrong” alive. Let new workers ask blunt questions and share old stories. The right attitude lowers risk as much as eye shields or spill kits ever could.
N-Trimethoxyoctylsilane, known in labs and across industries, sits in the lineup of organosilanes that help set modern materials apart from the past. It often comes as a clear, colorless to slightly yellow liquid. If you ever open a bottle, the smell walks right out—sharp, almost like a whiff of sweet solvent mixed with alcohol. At room temperature, it flows like most light organic liquids but packs a punch in the way it reacts with water and oxygen in the air. That tail, the octyl group, is what really separates N-Trimethoxyoctylsilane from its cousins. The tail gives it hydrophobic character, meaning water just beads up and rolls away from surfaces treated with this stuff.
On the chemical side, this molecule tends to live on the edge. The trimethoxy group attached to silicon doesn’t stand up to moisture. Tiny amounts of water set off a process called hydrolysis, where those methoxy groups turn into silanols and methanol. Over time, these new silanol groups start bonding with each other or reach out to the surface they’re sitting on. Once attached, N-Trimethoxyoctylsilane changes the way a surface interacts with liquids and even with other chemicals. That’s one reason it shows up so often in waterproofing sprays, masonry sealers, and treatments for glass and ceramics.
I learned pretty quickly in the lab that you can’t just leave this chemical sitting in an open beaker and wander off. It won’t explode, but it will start picking up water out of the air. Some folks outside the lab underestimate how much humidity can affect a sensitive liquid like this one. As it interacts with moisture, not only does the chemical transform on the spot, but the reaction throws off methanol, which carries risks of its own. That means storage in tightly sealed, dry containers is key, both for safety and for making sure the silane works as expected.
Once N-Trimethoxyoctylsilane bonds with a surface, it’s there to stay. The long octyl tail blocks water and other corrosive agents. In my experience working with building materials, glass, and automotive parts, the difference between a treated and untreated surface is easy to see. The treated surface stays dry, shrugs off dirt, and holds up better under harsh weather or chemical spill. This changes the maintenance routine and helps things last longer, from a skyscraper facade to a smartphone screen.
The industrial side isn’t the only place where this matters. Home improvement products often sneak this compound into stone and grout sealers. Spraying it onto your bathroom tiles forms an invisible barrier that keeps out mold and mildew. You probably never think about it, but every time water runs down those treated surfaces instead of soaking in, N-Trimethoxyoctylsilane is doing its job behind the scenes.
One concern that always comes up is the release of methanol during use and curing. Methanol’s vapor can be dangerous in high concentrations—a quick review of the material safety data sheet brings this home. Ventilation stays important for folks applying or curing this chemical indoors. In manufacturing settings, newer systems try to reclaim or capture the byproducts, protecting both workers and the environment.
N-Trimethoxyoctylsilane stands out for its ability to change materials in meaningful ways. For anyone handling construction, surface engineering, or home renovations, knowing its quirks and its boundaries isn’t trivia—it’s the difference between a lasting finish and a surface that falls apart at the first sign of trouble.
| Names | |
| Preferred IUPAC name | trimethoxy(octyl)silane |
| Other names |
n-Octyltrimethoxysilane Trimethoxy(octyl)silane Octyltrimethoxysilane n-Octyltrimethoxysilane Triethoxyoctylsilane |
| Pronunciation | /ɛn-traɪˌmɛθ.ɒk.siˈɒk.tɪl.saɪˌleɪn/ |
| Identifiers | |
| CAS Number | ["3069-40-7"] |
| 3D model (JSmol) | `[Si](OCCCCCCCC)(OC)(OC)OC` |
| Beilstein Reference | 6339600 |
| ChEBI | CHEBI:85268 |
| ChEMBL | CHEMBL185260 |
| ChemSpider | 22153 |
| DrugBank | DB13365 |
| ECHA InfoCard | ECHA InfoCard: 100.040.665 |
| EC Number | 203-929-7 |
| Gmelin Reference | 112013 |
| KEGG | C20016 |
| MeSH | D005912 |
| PubChem CID | 69113 |
| RTECS number | RN9350000 |
| UNII | 0U8N5Q317W |
| UN number | UN1993 |
| CompTox Dashboard (EPA) | DTXSID4020708 |
| Properties | |
| Chemical formula | C11H26O3Si |
| Molar mass | 221.38 g/mol |
| Appearance | Colorless transparent liquid |
| Odor | Odorless |
| Density | 0.946 g/mL at 25 °C (lit.) |
| Solubility in water | Insoluble |
| log P | 4.51 |
| Vapor pressure | <0.1 hPa (20 °C) |
| Acidity (pKa) | 13.6 |
| Basicity (pKb) | -3.6 |
| Magnetic susceptibility (χ) | -6.44e-6 cm³/mol |
| Refractive index (nD) | 1.420 |
| Viscosity | 2 mPa·s at 25 °C |
| Dipole moment | 1.2067 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 627.6 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -1158.65 kJ/mol |
| Pharmacology | |
| ATC code | No ATC code |
| Hazards | |
| GHS labelling | GHS02, GHS07 |
| Pictograms | GHS07,GHS02 |
| Signal word | Warning |
| Hazard statements | H226, H319 |
| Precautionary statements | P210, P233, P240, P241, P242, P243, P261, P271, P280, P303+P361+P353, P304+P340, P305+P351+P338, P312, P337+P313, P370+P378, P403+P235, P501 |
| Flash point | 104 °C |
| Autoignition temperature | 335°C |
| Lethal dose or concentration | LD50 Oral Rat: > 2,000 mg/kg |
| LD50 (median dose) | LD50 (median dose): Oral rat LD50 > 5,000 mg/kg |
| NIOSH | Niosh: VV8560000 |
| PEL (Permissible) | PEL: Not established |
| REL (Recommended) | 10 ppm |
| Related compounds | |
| Related compounds |
Octyltriethoxysilane Trimethylchlorosilane N-Trimethylsilyloctylamine Vinyltrimethoxysilane Methyltrimethoxysilane Octyltrichlorosilane Propyltrimethoxysilane |
