1-Pentanethiol: An In-Depth Commentary
Historical Development
Back in the early days of organic chemistry, researchers encountered thiols as malodorous byproducts, and among these, 1-Pentanethiol soon caught their attention. This sulfur-infused compound didn’t take long to earn a reputation for its pungent, reeking odor, which nearly everyone working with sulfur chemistry learns to recognize. Throughout the 20th century, as laboratories grew more advanced, so did methods for purifying and studying organic thiols, including pentanethiol. Instead of seeing it as just another smelly substance, scientists recognized its reactivity and value in synthetic chemistry and industrial processes. Over the decades, interest kept building, especially for applications in flavor chemistry, pharmaceuticals, and organic synthesis, shaping research directions in both academia and industry.
Product Overview
1-Pentanethiol carries the molecular formula C5H12S, also cataloged as n-pentanethiol. In its pure form, this compound stands as a colorless to slightly yellow liquid, exuding that characteristic, intense, disagreeable thiol scent. Chemical suppliers offer it under a variety of trade names, making it available for both laboratory and commercial buyers. Unlike some high-volume industrial chemicals, pentanethiol gets produced in modest quantities, typically for specialty applications where its unique chemical profile matters.
Physical & Chemical Properties
Anyone who’s ever opened a bottle in a well-ventilated lab won’t forget the odor—an intense, slightly skunky aroma that sticks around even at low concentrations. 1-Pentanethiol has a boiling point near 120°C and a melting point below -90°C, which means it behaves as a liquid at room temperature with a relatively high vapor pressure for an aliphatic thiol. Less dense than water and practically insoluble in it, it mixes well with common organic solvents like ethanol, diethyl ether, and benzene. Its chemical behavior is dominated by a reactive mercaptan (-SH) group, which forms strong bonds with metals and reacts readily with alkyl halides and oxidizers.
Technical Specifications & Labeling
Suppliers often provide pentanethiol with purity not less than 98%, listing specific gravity, refractive index, and certificates of analysis for transparency. Labels warn of strong odor, flammability, and the need for robust ventilation. Transport codes and UN numbers (such as UN 1993 for flammable liquid) appear on drums and vials, conforming to international safety and transportation standards. Spec sheets sometimes note moisture content, sulfur contaminants, and recommended storage conditions—usually tightly sealed containers, kept away from sources of ignition.
Preparation Method
Large-scale syntheses usually start with 1-chloropentane or another suitable alkyl halide, treating the precursor with sodium hydrosulfide in a liquid phase reaction. The resulting mixture often contains residual byproducts that require fractional distillation for removal. Some research environments still use older techniques, such as reacting pentanol with thionyl chloride followed by sodium hydrogen sulfide, though these carry more environmental and safety challenges due to harsh reagents and dangerous fumes.
Chemical Reactions & Modifications
Chemists value pentanethiol for how easily its -SH group participates in substitution and oxidation reactions. Oxidizing 1-pentanethiol with hydrogen peroxide or mild oxidants yields pentyl disulfide or sulfonic acids, both of which open new uses in material science and catalysis. Its ability to bind metals finds use in surface modification, self-assembled monolayers, and gold nanoparticle stabilization. Alkylation or acylation reactions let researchers create a range of derivatives for further studies, and the compound’s reactivity with electrophiles has helped in the elaboration of heterocyclic scaffolds and custom polymers.
Synonyms & Product Names
In catalogs and literature, pentanethiol appears as n-pentanethiol, amyl mercaptan, pentyl mercaptan, and 1-mercaptopentane. In older texts, you sometimes see amyl hydrosulfide, reflecting the outdated “amyl” root for five-carbon chains. Large chemical suppliers and distributors carry it under different SKUs and batch numbers, but the material itself remains largely consistent across producers who stick to standard purity grades.
Safety & Operational Standards
Every chemist working with pentanethiol gets familiar with strong odor control and ventilation requirements. It's flammable above 35°C, and its vapors can form explosive mixtures with air. Prolonged skin contact should be avoided because absorption, though slow, can lead to irritation or more severe symptoms. Personal experience makes it clear that gloves, chemical splash goggles, and well-sealed vessels remain non-negotiable. Due to its strong scent, even a minor spill tends to linger, pushing lab managers to mandate spill kits and pre-labeled containment drums. Handling this compound in fume hoods and complying with workplace exposure guidelines isn’t just a bureaucratic box to tick—it's about keeping the working environment bearable for all involved.
Application Area
Most research applications focus on pentanethiol as a starting reagent in organic synthesis, serving roles in pharmaceuticals and the development of sulfur-containing drugs. It also sees use in producing antioxidants, stabilizers, and custom surfactant molecules. In materials science, pentanethiol creates self-assembled monolayers on gold surfaces, a foundational tool in nanotechnology for modifying electrical properties or improving sensor surfaces. Food chemistry sometimes makes use of its intense odor profile in flavor development, mimicking the nuances of certain truffle or cheese notes, although high concentrations remain overwhelming and rarely find their way past flavor house test kitchens.
Research & Development
Modern research picks up where classic organic chemistry left off. Today’s scientific work dives deeper using advanced chromatography and spectroscopy to follow transformation pathways and minor byproduct formation. New developments come in surface chemistry, as pentanethiol’s strong gold affinity lends itself to work on biosensing layers and conductive nanofilms. Pharmaceutical groups experiment with its derivatives for improved drug delivery or novel biological activity. My own experience confirms that controlled environments and modern analytical techniques now sharpen understanding and open new directions.
Toxicity Research
Toxicological studies have shown that pentanethiol, like other aliphatic thiols, exerts its greatest effects through inhalation and skin contact. Acute exposure causes headache, nausea, and respiratory irritation at low levels, long before reaching established occupational exposure limits. Though its toxicity falls lower than some aromatic thiols, nobody who’s handled it would call it benign. Animal models indicate impacts on liver and kidney function at high doses, while ecological studies raise concerns around aquatic persistence due to low biodegradability and distinct sulfurous odor. Regulatory agencies set workplace limits and require detailed risk labels, underscoring that personal protective equipment and spill controls belong front and center.
Future Prospects
Emerging green chemistry initiatives have started to influence how chemists view pentanethiol’s future synthesis and use. Cleaner routes using less hazardous reagents are under development, and recycling strategies for spent thiols are gaining interest. Experts anticipate expanded roles for pentanethiol-modified surfaces in nanoelectronics, where molecular-scale structure tweaks drive big changes in device performance. There’s ongoing work to broaden its use in specialty medicines and custom intermediates, especially as high-throughput screening and computational modeling zero in on new sulfur-based drug candidates. The core challenge remains in safe handling and odor management, but the field keeps pushing boundaries, turning an old, smelly chemical into a tool for tomorrow’s science.
Walking Through Its Main Jobs
Most people haven’t heard of 1-Pentanethiol unless they’ve spent some time in a chemistry lab. It comes with a sharp, skunky smell that lets everyone know when a bottle is open. This isn’t just an oddity on a shelf — this chemical finds its way into several real-world applications.
1-Pentanethiol in Laboratories
Chemists and researchers use 1-Pentanethiol to build more complex molecules. They rely on its sulfur component for reactions where connecting two molecules through a sulfur atom makes all the difference. In organic synthesis, the thiol group reacts easily with metals and other elements, opening doors to new compounds that wouldn’t exist otherwise. It's a go-to for introducing sulfur into larger structures, especially in the world of pharmaceuticals and material science.
From Synthesis to Additives
Many know that refining crude oil demands a set of precise chemical reactions. 1-Pentanethiol slips in here as one of the helpers. Refineries turn to this compound when they need to get rid of heavy metal ions and sulfur-rich impurities. Clean fuels and lubricants often depend on small players like this, which step in to ‘trap’ or react away stuff nobody wants in a finished product.
Stopping Corrosion in Its Tracks
Bare steel and iron don’t last long when exposed to air and water. Factories and water plants care about this because rust slows equipment, eats away at bridges, and piles up repair bills. 1-Pentanethiol fights corrosion by forming a thin, protective layer on the surface. This film blocks oxygen and moisture from reaching the metal, keeping things usable for the long haul. There are other tools in the box for preventing rust, but this chemical’s ability to bond tightly with metal at the atomic level gives it an edge, especially where regular paint or oil wouldn’t hold up.
What 1-Pentanethiol Needs Attention For
Putting it to work in these roles brings its own safety responsibilities. I’ve handled sulfur-rich chemicals before, and the smell alone reminds you to keep that fume hood running. Thio-based organics can irritate the skin, eyes, and lungs. That sharp scent signals leaks — just as well, because you don’t want this drifting around a crowded space. Besides personal safety, disposal rules apply. Pouring leftover 1-Pentanethiol down the drain would never fly in a responsible workplace. Strong stuff like this can harm both people and wildlife if not managed carefully.
Room for Smarter Use
New research aims to reduce hazardous waste by designing recyclable or more degradable alternatives. Digital tools help researchers test small samples, lowering risks before moving up to bigger volumes. Automated systems pump chemicals under sealed conditions, keeping people at a safe distance while fine-tuning every step. Small steps, but each helps nudge better practices forward.
Final Thoughts
1-Pentanethiol plays a supported role behind the scenes. Building new molecules, cleaning up raw materials, and guarding metals from the elements add up to a safer, more efficient modern world. With smart handling and steady improvements, the benefits stand out alongside the risks.
What Makes 1-Pentanethiol a Concern?
1-Pentanethiol carries a reputation for its strong, disagreeable odor and its place among industrial chemicals worth handling with care. Anyone who’s spent time in a chemistry lab or worked in a chemical manufacturing setting knows it by the smell—like rotten cabbage but more intense. The hazards, though, go beyond offensive fumes.
Hazards to Human Health
Short exposures to 1-pentanethiol can trigger headaches, dizziness, and irritation in the eyes and throat. Inhaling even small amounts sometimes leaves you feeling off for hours. Prolonged or repeated contact brings skin irritation, redness, and sometimes blistering. Many workers, myself included, notice that handling this compound without nitrile gloves ends up with an itchy rash almost every time. Its vapor can impact the central nervous system, which makes proper ventilation a must. Anyone accidentally splashing this chemical in their eyes faces burning and possible damage that needs immediate flushing with water.
Fire and Reactivity Hazards
Flammability jumps out as a major hazard. 1-Pentanethiol ignites at relatively low temperatures, catching fire from hot surfaces, sparks, or static electricity. Once burning, it releases dense, toxic smoke. I remember a lab incident where improper storage led to a small fire—an overwhelming stench and panic in seconds. The fumes contain sulfur oxides, which can inflame airways and hurt the lungs if you’re too close. Anyone storing this compound learns quickly to keep containers tightly sealed, and never ever near sources of heat.
Environmental Spill Risks
Outdoors, spills of 1-pentanethiol threaten soil and water quality. Fish and aquatic life do not tolerate even trace levels in streams and ponds. Underground water supplies absorb these chemicals easily, making cleanup expensive and troublesome. Years ago, a minor spill at a facility I visited forced a full shutdown of their water outflow, along with months of ground remediation. Community members living nearby complained for weeks about the foul stench—an unmistakable sign that even small leaks matter.
Simple Steps to Safer Handling
Training and common sense go a long way. Always use chemical splash goggles and thick gloves. Good ventilation turns a risky workspace into one that’s manageable—fume hoods earn their keep here. Chemical storage rules save lives: keep 1-pentanethiol locked up, in well-labeled, tightly closed containers, far from sunlight and ignition sources. I always double-check containers before and after use, never trusting a lid that isn’t tight. Working in teams helps—if one person has an accident, at least someone else can respond right away.
Clear Labeling and Communication
Involving all staff with chemical safety makes a real difference. Label bottles clearly, and make sure new workers know what symptoms to look for—headaches, sore throats, even feeling slightly confused after exposure. Reporting symptoms quickly speeds up response and keeps problems small.
A Look at Better Solutions
Substitute less hazardous chemicals whenever possible, since not every lab process truly needs 1-pentanethiol. Invest in spill kits and regular safety drills. Keeping local fire departments in the loop about what chemicals live onsite adds another layer of backup. If it seems like overkill, try talking to someone who’s cleaned up a major chemical spill—the lessons learned stick around for life.
Getting to Know 1-Pentanethiol
Before diving into formulas, let’s put things in perspective. People often get tripped up by chemical names, but 1-pentanethiol keeps it pretty simple. This molecule is a five-carbon chain with a sulfur atom holding a hydrogen atom at one end. That arrangement sets it apart from straight-chain alcohols or alkanes. The real kicker: its chemical formula reads as C5H12S.
Why the Formula C5H12S Matters
It’s not just about the number of atoms crammed into a chain. That S at the end stands for sulfur, making the substance a thiol. If you’ve ever peeled back the label of a strong-smelling product—think rotten eggs or skunk spray—there’s a good chance some thiols made your nose wrinkle. These compounds have a low odor threshold; it only takes a tiny whiff for humans to pick them up. That’s a fact often confirmed in teaching labs (mine included) after a single pipetting mishap.
The whole point of knowing the formula extends past the basics. Labs need it to calculate molar masses, set up reactions, and keep their work safe. Field techs tracking chemical spills or alerting the public lean on these formulas to decide how best to neutralize or contain something. I’ve witnessed fire departments pull up hazard sheets keyed to these formulas whenever they identify a weird smell after an accident. Safety hinges on these fine details.
Beyond the Textbook: Where 1-Pentanethiol Shows Up
1-Pentanethiol doesn’t earn much spotlight in high school classes, but it finds a home in research and industry. Chemists often use it while making more complicated molecules or as part of custom flavors and scents (in tiny, carefully controlled amounts). During one of my undergraduate summer internships, it showed up in a project on corrosion inhibitors—scientists sometimes use thiols like this for their affinity to metals, sticking to surfaces and forming protective layers. The formula tells you exactly what’s present, and that matters to both innovation and safety.
Balancing Opportunity and Risk
Any time sulfur sits in a molecule, risk comes along for the ride. Thiols can react in surprising ways, especially next to open flame or oxidizing agents. C5H12S offers a good reminder that understanding structure ties directly to how a chemical behaves. Mislabeling or guessing means trouble. Over the years, I’ve seen even experienced chemists double-check bottle labels after a single unfavorable reaction—nobody wants a stink bomb or worse in the lab by accident.
If you wonder about solutions, it’s all about access to reliable training and clear communication. Too many accidents happen because someone forgets what a thiol is or mixes up similar-sounding names. Industry groups, universities, and safety trainers need a hand in keeping chemical literacy sharp. Resources that break down formulas like C5H12S into their real significance—smell, reactivity, environmental impact—work better than rote memorization. Good habits (like double-checking reagents and storing sulfur compounds safely) do more to prevent headaches and hazards than any rulebook ever written.
Respecting the Real Risks
Anyone who’s cracked a bottle of 1-pentanethiol knows the odor makes its presence felt. That strong scent hints at something more important—this material isn’t just unpleasant, it carries some hazards too. One whiff in the lab and you never forget to tighten the cap. Beyond its smell, 1-pentanethiol raises concerns about flammability, toxicity, and effect on the environment if it leaks. You can’t treat it like table salt.
Thinking About Storage Location
Chemicals with a strong sulfur smell like this won’t get lost on your shelf, but the real issue comes down to safe placement. Store it in a cool spot, away from heat, sparks, or open flames. Flammable materials love to find trouble given the chance. Keeping this compound away from direct sunlight helps, too—a lesson I’ve learned after seeing discoloration and crusty residues build in forgotten vials.
Choosing the Best Container
Glass containers with tight, chemical-resistant caps stand up best over time. Polyethylene can work, as long as the cap keeps vapors trapped. Never use porous or worn-out containers. I remember discovering a small leak in a cheap plastic bottle, and the smell lingered for weeks. That proved a tight seal and a quality vessel matter more than convenience.
Thinking About Chemical Neighbors
Store 1-pentanethiol apart from oxidizers, acids, and anything that tends to react with thiols. A surprising mix-up can kick off chemical reactions nobody wants to handle. I’ve seen labels fade and people forget what’s in which bottle, so clear labeling makes all the difference. No shortcuts: use permanent lab markers, not sticky notes.
Ventilation Helps Everyone
The right storage cabinet for volatile chemicals really pays dividends. A ventilated, spark-proof storage cabinet isn’t a luxury in labs or storerooms where chemicals like this get regular use. Even a small fume can irritate your nose and eyes all day. Good air flow also protects coworkers and limits the risk of a subtle buildup of vapors.
Excel at Labeling and Documentation
In every serious lab, labeling isn’t negotiable. Put the name, concentration, and date received or last opened on the container. Many forget expiration dates, but keeping old, degraded pentanethiol around only invites trouble. In case of emergencies, responders know what they’re dealing with if the label says it all. Training people to check these details beats relying on memory.
Personal Experience Sets the Standard
Over a decade working next to chemical storage shelves taught me to never shrug off handling instructions. The rules exist because someone got it wrong before. Consulting material safety data sheets keeps the team aware of risks and proper storage practice. In my lab, a shared culture of safety catches problems before they escalate.
Better Storage Means Fewer Problems
Problems snowball fast if chemicals aren’t stored properly. Painful headaches, skin rashes, and possibly much worse can all follow sloppy habits. Investing in decent storage, strong training, and strict routines shows respect for everyone’s health—and for the science itself. Even small changes in storage habits will keep mistakes rare and everyone breathing easier.
What Makes 1-Pentanethiol Stand Out?
1-Pentanethiol, also called amyl mercaptan, enters a room long before its container opens. This liquid brings a punchy, sulfur-heavy aroma that so many in the lab world recognize from miles away. Its smell hits hard thanks to the thiol group. Most folks who’ve worked with it once don’t forget the sharp reminder: a little goes a long way. In that sense, 1-pentanethiol stands in a different corner than the rest of the pentane family, mostly because that sulfur atom changes everything from handling habits to proper storage techniques.
Clear in Color, Wild in Odor
Clear liquids often slip under the radar, but don’t let the lack of color fool you. A bottle of 1-pentanethiol looks like plain water, yet reacts like anything but. The compound boils off at around 120–122 °C and freezes at -89 °C. Run your hand along the bottle and you’ll notice a slick, oily feel, not a hint of stickiness or grain. It’s less dense than water, floating up at around 0.832 g/cm3. Dump it in water? It floats right on top.
Flammability and Reaction Warnings
Storing this compound demands some respect. It catches fire with the ease of a dry pine tree—its flash point rests just above room temperature, at about 29 °C. I’ve watched a small spill light up a waste drum faster than expected. It’s worth noting how quickly 1-pentanethiol forms explosive mixtures with air. Spark sources must stay clear, and fume hood vents should run strong whenever the container’s open.
This chemical also doesn’t shy away from reaction, especially with oxidizing agents. It forms disulfides or starts to break down under sunlight. Producers ship it in amber bottles for a reason, and labs that forget end up scrubbing sticky residues off benches for days.
Solubility: Water Can’t Keep Up
No matter how much you mix, water simply shrugs off 1-pentanethiol. It dissolves more eagerly in organic solvents—ethanol or diethyl ether have both played their part as partners in my hands. This trait sits at the center of its use in organic synthesis, where separation from water helps streamline purification. Chemists often use high-boiling solvents or distillation setups to keep things under control.
Hazards, Exposure, and Personal Experience
There’s no way around wearing gloves and goggles. The odor leaks into hair and clothes, a curse that lingers after a long day in the lab. Reports from colleagues who’ve splashed it on skin mention rapid irritation. A short stint with improper ventilation led to watery eyes and that metallic taste in the mouth—enough of a lesson for anyone.
In terms of solutions, many labs set up work in dedicated thiol hoods, or work towards miniaturizing reactions to reduce exposure. Following proper labeling, and using vapor traps or scrubbers, pays off in fewer headaches—literally and figuratively.
Reliable Data and Practical Application
Building a strong understanding of 1-pentanethiol’s physical facts does more than satisfy curiosity; it helps keep people safe, and projects on track. Safety sheets from sources like Sigma-Aldrich supply accurate boiling and melting points, while the CRC Handbook adds depth with specific refractive index values (about 1.445 at 20 °C). With these, you step up to the bench prepared, not surprised.
| Names | |
| Preferred IUPAC name | pentane-1-thiol |
| Other names |
n-Pentanethiol
Amyl mercaptan Pentyl mercaptan 1-Mercaptopentane n-Amyl mercaptan |
| Pronunciation | /paɪˈtæn.əˌθaɪ.ɒl/ |
| Identifiers | |
| CAS Number | 110-66-7 |
| Beilstein Reference | 1641006 |
| ChEBI | CHEBI:35987 |
| ChEMBL | CHEMBL16843 |
| ChemSpider | 7097 |
| DrugBank | DB14109 |
| ECHA InfoCard | ECHA InfoCard: 100.004.349 |
| EC Number | 203-696-6 |
| Gmelin Reference | 69079 |
| KEGG | C01728 |
| MeSH | D010412 |
| PubChem CID | 8049 |
| RTECS number | SK8400000 |
| UNII | CF5G8K04FO |
| UN number | UN 2327 |
| CompTox Dashboard (EPA) | DTXSID5020624 |
| Properties | |
| Chemical formula | C5H12S |
| Molar mass | 104.21 g/mol |
| Appearance | Colorless liquid |
| Odor | unpleasant strong odor |
| Density | D: 0.835 g/mL at 25 °C(lit.) |
| Solubility in water | insoluble |
| log P | 2.85 |
| Vapor pressure | 1.5 mmHg (20 °C) |
| Acidity (pKa) | pKa = 10.6 |
| Basicity (pKb) | SEV: 3.56 |
| Magnetic susceptibility (χ) | -74.6×10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.444 |
| Viscosity | 2.71 mPa·s (20 °C) |
| Dipole moment | 1.66 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 218.7 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -117.9 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -3781.7 kJ/mol |
| Hazards | |
| GHS labelling | GHS02, GHS06, GHS07, GHS08 |
| Pictograms | GHS06,GHS08 |
| Signal word | Warning |
| Hazard statements | H226, H301, H311, H315, H319, H331, H335, H400 |
| Precautionary statements | H225, H302, H311, H314, H331, H411 |
| NFPA 704 (fire diamond) | 2-3-0 |
| Flash point | 40 °C (104 °F; 313 K) - closed cup |
| Autoignition temperature | 215 °C |
| Explosive limits | 1-4.4% |
| Lethal dose or concentration | LD50 oral rat 132 mg/kg |
| LD50 (median dose) | LD50 (median dose): Oral rat LD50 = 600 mg/kg |
| NIOSH | PA9400000 |
| PEL (Permissible) | PEL (Permissible Exposure Limit) for 1-Pentanethiol: "1 ppm (skin) |
| REL (Recommended) | REL: 1 ppm |
| IDLH (Immediate danger) | 250 ppm |
| Related compounds | |
| Related compounds |
1-Propanethiol
1-Butanethiol 1-Hexanethiol 2-Pentanethiol Pentanol Pentanal |
