About a century ago, the chemistry world found itself looking for ways to control surfaces at the molecular level. Back in the 1940s, surfactants and organosilanes attracted attention, but it wasn’t until silicon-based reagents like N-Octadecyltrichlorosilane (OTS) appeared on the scene in the early 1950s that researchers began crafting ultra-thin films and changing the way materials interacted. Laboratories from Europe to the United States, each grappling with the hurdles of surface contamination and poor adhesion, saw strong benefits using OTS for its hydrophobic qualities. Scientists covered glassware, upgraded electronics, and tinkered with biomedical applications, all the while experimenting and publishing outbreak after outbreak of promising results. The shared hunger for reproducible, stable surface chemistries gave OTS a prominent role in material science as the decades rolled by.
N-Octadecyltrichlorosilane belongs to the class of organosilanes, with a lengthy hydrocarbon tail. This gives it a unique dual character—part silicon, part fatty alkyl chain. Because of this, teams in both academic and industrial labs keep it in their toolkit. It stands out for building self-assembled monolayers, mainly on oxide surfaces like glass or silicon wafers. Picture a molecule that locks one end firmly onto a surface, with the long “tail” pointing out, making a low-energy, water-repellent layer. Chemists preparing surfaces for microelectronics, sensor development, or even simple anti-fouling coatings reach for OTS. Over time, commercial grades have become more standardized, so the product arriving in glass bottles from specialty suppliers can be counted on for purity and ease of handling.
N-Octadecyltrichlorosilane appears as a colorless to faintly yellow liquid, viscous and with a noticeable pungent odor, a sign of its reactive silicon-chloride bonds. Think oily, almost syrup-like, hinting at its 18-carbon tail. It doesn’t like water; contact triggers an energetic hydrolysis, releasing hydrochloric acid and white smoke, so it demands respect and careful storage. Its melting point is low, so it stays as a liquid at room temperature. OTS remains soluble in organic solvents like toluene or hexane. While exposed to moisture in air, it starts to degrade, so people keep it tightly sealed under inert gas. The chemical structure means it assembles well onto hydroxylated surfaces, which is why glass cleaned with piranha solution or silicon dioxide are common targets for monolayer formation.
Any laboratory bottle of OTS comes with clear, detailed labels because mishandling this chemical brings substantial risk. Standard labels specify purity (usually above 95%) and water content (as low as possible), along with recommended storage—cold, dry, and away from acids or bases. You’ll spot the CAS number 112-04-9 and warnings about moisture sensitivity and corrosiveness. Even in a busy lab, you can’t mistake OTS for anything else, thanks to its chemical fingerprint and distinctive labeling. Most suppliers describe it as a moisture-reactive, organosilane compound, assigning UN 1760 for hazardous material transport. Specialty labs tracking inventory treat this with extra caution, logging each batch and clearly highlighting its aggressive reactivity on data sheets.
Synthetically, OTS results from the reaction between octadecyl alcohol and silicon tetrachloride in an anhydrous environment. The process demands attention to dryness and low humidity—any trace of water leads to unwanted hydrolysis and low yields. After reaction, distillation at reduced pressure removes any leftover reactants and by-products, leaving behind the desired silane. This method has become streamlined; reputable suppliers achieve high efficiencies and purity, but researchers synthesizing small batches still need fume hoods, protective gear, and well-sealed glassware. One crucial part of my own laboratory training involved drying all glassware to eliminate stray water—a step you never forget after seeing firsthand the hazards of skipping it.
OTS stands out for its aggressive reactivity with hydroxyl groups. In a practical sense, scientists use it for silanization of glass or silicon surfaces. Shake cleaned glass slides in a solution of OTS—usually in toluene—and after a short soak, a monolayer forms. Only the initial surface hydroxyls react, which leads to nearly one molecule thick coverage, perfect for creating controlled interfaces. Excess OTS can trigger multilayer growth or patchy films, so optimization becomes crucial in advanced device fabrication. The trichlorosilane head group remains central to its chemistry, offering sites for further reactions, though in most applications, people prefer its stability after initial binding. Modifications include introducing functional groups on the tail section, leading to specialty OTS derivatives that anchor other chemical entities or biomolecules.
In catalogs and publications, you might see N-Octadecyltrichlorosilane written as OTS, or listed under names like Octadecyltrichlorosilane, or even n-octadecyltrichlorosilane. Some refer to it as Stearyl trichlorosilane or use supplier-specific product codes. These aliases show up in research papers, patent filings, and safety datasheets. With multiple synonyms, laboratories weave a web of cross-references, but most researchers and supply companies now stick to OTS for shorthand.
OTS demands serious respect for safety, thanks to its reactivity and corrosiveness. Hydrolysis produces hydrogen chloride gas, an acute respiratory hazard. In lab settings, all work involving OTS must go inside a certified chemical fume hood. Technicians wear nitrile or butyl gloves, tight-fitting goggles, and lab coats. Any accidental contact means immediate flushing with water—delays dramatically boost burns or irritation. Ventilation, spill kits, and properly labeled containers reduce risk of exposure to fumes or accidental splashes. Waste from workups, contaminated glassware, and spent silane gets segregated and destroyed as hazardous waste. Failure to follow protocols can result in injuries or ruined equipment—so teams stay sharp and conduct regular safety drills. Industry and university compliance audits reinforce strict rules for purchase, handling, and storage.
Over the last few decades, OTS found a loyal user base in nanotechnology, microelectronics, sensor design, and advanced coatings. In the nanoscience community, self-assembled monolayers produced with OTS form the basis for molecular electronics, biosensor chips, and microfluidic devices. It adds hydrophobic character to surfaces, which helps minimize fouling or unwanted absorption. Electronics manufacturers use OTS to tune surface energy, aiming at improved photolithography and microfabrication results. In my own work, applying OTS to glassware improved the shelf life of fragile suspensions by reducing unwanted interactions at glass-liquid interfaces. Researchers push OTS chemistry even further by attaching biologically active molecules, letting them control cell attachment and growth on implants or test chips.
OTS remains at the center of innovation because it solves many real-world problems in controlling surface chemistry. Scientists constantly publish new protocols involving OTS modified surfaces for advanced sensing, catalysis, organic solar cells, and nano-patterning. R&D groups dig deep, seeking new functionalization strategies—tailoring OTS molecules to allow later covalent attachment of biomolecules or catalysts. Some focus on improving reproducibility and film quality, battling perennial issues like multilayer formation or incomplete coverage. Data from published research show that process variables—solvent, humidity, substrate cleaning—lead to significant differences in film properties, prompting ongoing method development. Collaborative projects across physics, chemistry, and engineering keep pushing OTS technology forward, from molecular electronics to medical diagnostics.
A chemical with such aggressive reactivity as OTS invites careful toxicological investigation. Hydrolysis gives off hydrochloric acid, so acute exposure may cause burns to skin and eyes, plus respiratory damage if inhaled. Chronic exposure data remain sparse, but animal studies highlight corrosive properties over long-term, low-level exposures. Risk assessments conducted at institutions emphasize the need for containment and rapid response to spills. Hazard information points to OTS not being environmentally friendly; waste must be tightly managed to prevent release into aquatic systems. My own research teams always incorporated rigorous cleanup, air monitoring, and personal health surveillance when experiments involved OTS. The profession at large recognizes that periodic, repeated exposure carries risks that demand lifelong workplace vigilance and strong standards.
Looking ahead, OTS chemistry keeps gaining ground in micro- and nanofabrication. Current trends favor hybrid electronics, wearables, and medical diagnostic tools, all of which need reliable surface coatings and functionalization. Researchers in renewable energy investigate OTS coatings to improve solar cell interfaces and device longevity. Industry looks for greener analogs, targeting reduced by-products and safer handling. Interdisciplinary teams continue to ask how OTS-inspired molecules can trigger more complex self-organization, giving rise to novel sensors, adaptive materials, or smart drug delivery surfaces. With every advance, the focus remains on combining high performance with real-world safety and environmental responsibility. Academic journals regularly report on breakthroughs in OTS modification, giving students, engineers, and industrial chemists new ideas for future exploration.
N-Octadecyltrichlorosilane (OTS) shows up in plenty of research papers and lab supply sites. What grabs people about this compound? For years, scientists have looked to OTS because it brings real changes to surfaces. The core idea behind using OTS comes down to its long hydrocarbon tail and reactive trichlorosilane group. These features turn regular glass or silicon into water-repellent materials. That’s not just lab magic—companies and universities use this trick for testing, manufacturing, and upgrading materials.
Students working in a university chemistry lab quickly learn about hydrophobic coatings. Glassware prepped with OTS beads water, saving time on cleanup. Long after class, this same property helps build biosensors. Chipmakers, especially those working on microelectromechanical systems (MEMS), treat silicon wafers with OTS. Water and dust slide off. The devices last longer and perform reliably. This matters for things like accelerometers in phones. Precise sensors need clean, dry surfaces, and OTS delivers on that front.
Printing minuscule patterns looks simple on screen, but real-world surfaces complicate things. OTS forms a monolayer—a single molecule thick. This allows researchers to stamp delicate patterns for electronics or study how cells react to specific textures. Microcontact printing, a popular method in biotechnology, uses OTS to create spots where only certain interactions happen. Companies exploring DNA chips or advanced coatings for medical devices use OTS-based methods to control how proteins or cells attach, boosting accuracy and reliability in sensitive assays.
In some alternative energy research, efficiency rides on each interface in the device. Take dye-sensitized solar cells. Coating an electrode with OTS changes how light, electricity, and moisture interact. Uncoated surfaces absorb water and degrade fast, but OTS treated ones shrug off humidity. Simple hydrophobic layers slow the march of corrosion and stretch the life of these solar cells. These improvements make the quest for green energy more practical.
OTS coatings bridge the gap between idea and usable tech. A few years back, a colleague showed me cleaned microscope slides dipped into an OTS solution. The slides dried in about an hour and water droplets rolled right off. No more streaks. That work sped up sample prep for imaging. I’ve heard similar stories from engineers tuning circuits or researchers working on ultrasensitive chemical sensors.
Not every material or lab needs OTS. But projects that wrestle with moisture, static, or sticky molecules find real value in it. For people working in clean rooms or anyone building miniaturized devices, this compound feels a bit like insurance: invisibly reliable, but crucial for steady performance.
OTS lays down a protective layer, though careful handling is needed. Hydrolysis during application produces hydrochloric acid, which calls for solid safety protocols. Waste disposal can't get ignored if we mean to protect lab staff and the nearby environment. Some new research focuses on greener solvents and lower temperatures for safer and more sustainable coating processes.
Scientists and engineers who use OTS keep pressing for faster, less-toxic methods that scale well. If those come together, more products and research fields will take advantage of what started as a niche chemical.
In labs and manufacturing, N-Octadecyltrichlorosilane, often called OTS, finds real use in creating protective coatings and fabricating microelectronic devices. This chemical reacts quickly and isn’t friendly to anything with water in it, including your skin or lungs. Storing and handling OTS wrong sets up employees and workplaces for harsh accidents that may turn serious fast.
OTS looks harmless until a small leak or careless stash leads to a mess. Keep it in tightly sealed glass containers, never plastic, because it eats through weaker barriers. Find a cool, dry storage spot, away from sunlight or anything damp. Heat or moisture triggers a strong reaction, releasing hydrogen chloride gas—a toxic, corrosive fume that finds airways and burns. I have seen small leaks melt labels and corrode steel shelving in less than a week.
Lab rules I remember from grad school saved close calls: mark the OTS shelf clearly and never keep acids or strong bases nearby. In workplaces, staff do regular checks for cracks or bad seals on bottles. Rust or sticky residue usually means it’s leaking, which can ruin everything around it. Open the storage room’s window or make sure ventilation pulls fumes outside.
Pouring or drawing out OTS should always happen in a fume hood. The vapor smells sharp and clings to surfaces. Never trust bare skin: use gloves made from nitrile or butyl rubber. Cheap latex breaks down in seconds. Safety goggles—wraparound style, not just glasses—keep splashes out of your eyes. Lab coats and closed shoes count as minimum gear.
One thing I learned working as a research assistant: spills happen, and rushing makes things worse. Small drips dry sticky and don’t come off with water. Cleaning needs a strong base, like sodium bicarbonate solution, to neutralize the chemical. After cleaning, wipe down every tool and surface. Bottles must get closed right away, and empty containers can’t go straight to the trash. Triple rinse the bottle with a safe solvent, let it dry, then dispose of it as hazardous waste.
No workplace protects itself without regular safety training. Teams go over chemical hygiene plans, practice using spill kits, and learn who to call for big accidents. People remember stories more than written policies. One summer, I saw a PhD student knock over an OTS flask. The spill filled the fume hood with acid smoke, and his lab partner pulled the emergency button. Fast action and clear training kept the situation under control, no serious injuries. Experience brings home the idea that checklists and drills are not empty rituals—they save time and sometimes lives.
Facilities improve safety with real-time monitoring: air quality sensors, visible warning signs, and step-by-step guides fixed to the walls. Labeling isn’t just bureaucratic—it stops confusion when seconds count. If OTS starts reacting or spilling, teams know exactly which extinguisher works (dry chemical, never water), where the eyewash station hides, and how to exit safely.
Encouraging a culture that looks out for one another has long-term benefits. New workers learn from veterans, and ideas for better storage or updated personal protective equipment come from weekly feedback sessions. Routine audits spot changes before trouble hits, and companies who share incident reports help everyone across the field. In the end, storing and handling OTS safely is never a checklist item—it's a commitment to real lives and real work.
N-Octadecyltrichlorosilane, known in many labs by its shorthand OTS, doesn’t make headlines, but it finds a home in research institutions, especially those working with glass, silicon, or metal surfaces. Its job is straightforward: produce a thin and hydrophobic layer on surfaces to keep things clean, free of water, and less likely to stick. As someone who’s spent many hours hunched over a fume hood, I understand that a mistake with this chemical can spell disaster for your experiment and your own well-being. Not all chemicals that change how a surface behaves come with dangerous fumes, but OTS does, and treating it carelessly isn’t just reckless — it’s unnecessary.
The best results come from a careful and methodical approach. Before anything else, the surface has to be squeaky clean. Any leftover residues or bits of oil ruin the layer and make results unpredictable. In practice, glassware often gets an acid clean using piranha solution (a nasty mix of sulfuric acid and hydrogen peroxide that will eat through skin just as fast as it takes care of organic dirt). Safety gear is not optional here: real labs always insist on gloves, goggles, and proper ventilation.
Once the surface passes inspection, it’s time to choose a method for putting the OTS on. Most researchers swear by the dip-coating technique. You pour a dilute solution of OTS in a dry, water-free solvent like toluene, then lower the clean sample into the liquid and let it soak. In my experience, concentrations around 0.1–1% OTS work best to avoid thick, patchy films. People who rush this crucial step or use water-contaminated solvents end up with non-uniform coatings and lots of frustration. After soaking (ten to sixty minutes, usually), the sample moves to a fresh solvent bath to rinse off any leftover OTS that didn’t bond. At this stage, patience and attention to detail mean the difference between clean success and repeating the entire process.
Some folks try vapor-phase deposition instead, and it does offer less solvent waste. But this method calls for controlled humidity and precise temperatures. Miss the target, and you get incomplete coverage or unwanted siloxane polymers forming on the surface. My result from this method rarely matched the perfection promised in papers, unless I invested in expensive humidity control gear. That’s one reason dipping the samples in the solution remains the gold standard in most labs.
The real risk lies in failing to control moisture. Any hint of water starts a rapid, exothermic reaction, spinning off hydrochloric acid fumes that are dangerous to breathe. People sometimes cut corners to speed things up, which always ends badly. I’ve seen glassware etched, coatings ruined, and researchers coughing uncontrollably from a poorly vented fume hood. Respecting proper PPE, investing in dehumidifiers, and working slowly all play a part in keeping both people and samples in good condition.
If you want reliable results with OTS, master your cleaning routine, use dry tools, and pay attention to each preparation step. Maybe automation will one day remove some headaches, but in research and industry setups today, success still relies on old-fashioned caution, a steady hand, and an unwavering respect for what’s in your beaker.
N-Octadecyltrichlorosilane, or OTS for short, doesn’t get much attention outside labs and workshops. This chemical shows up as a colorless to pale yellow liquid, giving off a sharp, almost choking odor. If you've ever opened a bottle in an unventilated room, you'll remember the bite in the air. Its molecular formula is C18H37Cl3Si, straight to the point. Folks using it will notice it’s oily, trickling slowly and staining almost everything it touches. At room temperature, it holds together as a dense liquid and refuses to mix with water due to its long hydrocarbon tail. Even a drop on moisture-laden skin triggers a reaction. OTS loves dry, inert environments—one run-in with water, and you’re dealing with a tough, glassy mess.
The “trichlorosilane” part of its name signals the biggest headache for people handling OTS. Those three chlorine atoms bonded to silicon hypercharge the molecule. Pour OTS near water or even in a humid room, and the chloride groups explode into action, forming hydrochloric acid on contact. It doesn’t just sting the nose; it chews up skin, eyes, and metal surfaces. Careless handling in a humid lab usually ends with etching and corrosion. For all this reactivity, OTS stores best under nitrogen, far from glassware cleaned with tap water. Bit of a paradox, since you need glass slides for OTS to do its best work—coating, waterproofing, building those unique self-assembled monolayer films that support sensor technology and nanoscience research.
This stuff has a long, greasy molecular tail—think of a chain of eighteen carbons capped with a head ready to react. As a pure substance, OTS shows a boiling point around 391 °C, although it will decompose before it ever reaches that temperature in open air. In small spills, you’ll notice its slipperiness and reluctance to budge under water; it floats and spreads fast. Its vapor is heavier than air, drawn down to the floors where it can linger and cause trouble for anyone cleaning up. While it solidifies a bit below 10 °C, storing it cold makes it hard to measure out accurately, so most labs keep it at room temperature in tightly sealed containers.
Working with OTS feels like walking through a minefield for people not prepared with the right safety gear. Beyond the hydrochloric acid it spits out, any misstep—cracked glassware, forgotten bottle cap—can cost hours in clean-up. Those chemical properties make OTS great at forming water-repellent surfaces, but also make it almost impossible to reverse a mistake. I’ve seen glassware ruined by leftover OTS; rinse one pipette sloppily and that tool won’t see a clean surface again. Ventilation and gloves are not optional here; use goggles, too. Industry standards point out the dangers, and OSHA sets clear exposure limits. Following their advice isn’t just a rule—long-term exposure leads to chemical burns, lung irritation, and environmental hazards. Disposal brings another round of headaches, since hydrolysis products can harm aquatic life. Recycling solvents and using closed systems reduce these risks.
OTS plays a big role in surface science and electronics, giving scientists a way to control how surfaces react to water and organic materials. Its properties push forward research into biosensors and flexible materials—fields where controlling a tiny detail on the atomic layer changes the whole project. While it brings risks, clear safety guidelines and properly trained staff can make its use practical. Labs achieving best results commit to strong air handling, proper storage, and ongoing training. Responsible use puts powerful chemistry in skilled hands, turning a tricky liquid into valuable discoveries.
N-Octadecyltrichlorosilane isn’t the kind of stuff you just pour down the drain. With that long chemical name comes a kind of weight – and not just on the tongue. It's a silane compound, used often for making surfaces repel water or as a part of nanotechnology. It reacts quickly with water, releasing hydrochloric acid and forming a stubborn, sticky residue. This reaction means it brings both environmental and personal health hazards. Skin contact can cause burns, and the vapors are tough on the lungs. Uncaring disposal turns a useful lab chemical into a public and environmental risk.
I’ve seen up close what happens when folks don’t give chemicals like this enough respect. Early in my laboratory days, someone tossed a mostly empty bottle into a trash can. Next rainstorm, the container leaked. Waste handlers complained about chlorine odors. Lessons like this stick. There’s no shortcut for safe practices. If you’ve worked with silanes or strong acids, every spill cleanup and every stubborn reaction with humidity is a reminder.
Clear labeling matters. Leaving containers unmarked or loosely capped lets problems multiply. People move them, thinking they’re empty or safe. Even trace residue in a bottle will hiss and spit vapor when exposed to water. Spill response is no joke. Eye protection, gloves, and a fume hood aren’t optional accessories. Chemical splash burns take a long time to heal.
Empty containers aren’t really empty in the world of silanes. Rinsing with water releases acid, so dry, inert solvents like heptane or dry toluene dodge violent reactions. After that, containers need plenty of airing-out time under a fume hood. Air dries out leftover fumes, making them less of a threat.
Disposal must go beyond tossing stuff in the regular trash. Local regulations set the standard, and for good reason. Hazardous waste sites take these containers because they can treat and neutralize them. It costs money, true, but avoids hospital bills, fines, or environmental messes down the road. In many universities and research companies, chemical hygiene officers track every bottle. They collect spent containers, rinse, neutralize, and then ship them out as hazardous waste.
Every choice matters here. Careless disposal brings hydrochloric acid and silicone byproducts into water systems, sewer pipes, and landfills. Fish, plant life, and soil systems bear the brunt, which eventually catches up with people too. Safer handling keeps not just workers but whole neighborhoods safer.
Using secondary containment trays during storage and transport traps leaks and spills before they start. Encouraging colleagues to keep storage records and review safety data sheets means new lab members pick up good habits before old ones retire.
Many labs could stand to keep better records or use pictograms instead of hard-to-read labels. Regular training, more frequent than the annual checklists, keeps safety practical and memorable. I’ve found that step-by-step disposal guides stuck on chemical cabinets remind even busy scientists to slow down.
Manufacturers can pitch in too, offering return programs or safe disposal info right on packaging. No one needs to handle these cans or bottles alone; environmental health and safety offices have seen every disposal mistake in the book and know how to help.
Relying on luck or experience alone can’t replace learning from the right resources and staying mindful. Every careful disposal avoids a mess for someone else, which is worth remembering at the end of every long lab day.
| Names | |
| Preferred IUPAC name | N-octadecyl(trichloro)silane |
| Other names |
Octadecyltrichlorosilane OTS Stearyl trichlorosilane Trichloro(octadecyl)silane |
| Pronunciation | /ɛn ˌɒk.təˈdeɪ.sɪlˌtraɪˌklɔː.rəˈsɪ.leɪn/ |
| Identifiers | |
| CAS Number | 112-04-9 |
| Beilstein Reference | 1461326 |
| ChEBI | CHEBI:85174 |
| ChEMBL | CHEMBL372470 |
| ChemSpider | 16211 |
| DrugBank | DB07064 |
| ECHA InfoCard | 100.034.639 |
| EC Number | 208-809-6 |
| Gmelin Reference | 78717 |
| KEGG | C14433 |
| MeSH | D017622 |
| PubChem CID | 3034611 |
| RTECS number | VO1556000 |
| UNII | J629LHJ529 |
| UN number | UN2927 |
| Properties | |
| Chemical formula | C18H37Cl3Si |
| Molar mass | 401.16 g/mol |
| Appearance | Colorless to pale yellow liquid |
| Odor | Odorless |
| Density | 0.97 g/mL at 25 °C (lit.) |
| Solubility in water | Insoluble |
| log P | 14.86 |
| Vapor pressure | 0.03 mmHg (20 °C) |
| Acidity (pKa) | -0.3 |
| Basicity (pKb) | pKb: -2 |
| Magnetic susceptibility (χ) | -82.0e-6 cm³/mol |
| Refractive index (nD) | nD 1.457 |
| Viscosity | 3 cP (25 °C) |
| Dipole moment | 3.2032 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 869.6 J·mol⁻¹·K⁻¹ |
| Std enthalpy of combustion (ΔcH⦵298) | -11670 kJ/mol |
| Hazards | |
| GHS labelling | GHS02, GHS05, GHS07, GHS08 |
| Pictograms | GHS05,GHS07,GHS08 |
| Signal word | Danger |
| Hazard statements | H314: Causes severe skin burns and eye damage. |
| Precautionary statements | P261, P264, P271, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P312, P337+P313, P362+P364 |
| NFPA 704 (fire diamond) | 3-2-2-W |
| Flash point | 113 °C |
| LD50 (median dose) | LD50 (median dose): Oral, rat: > 5,000 mg/kg |
| NIOSH | WA7750000 |
| PEL (Permissible) | Not established |
| REL (Recommended) | 1 mg/m³ |
| Related compounds | |
| Related compounds |
Octadecyltrimethoxysilane Octadecyltriethoxysilane Trimethylchlorosilane Trichlorosilane |
