Cresyl Diphenyl Phosphate started to emerge during the rise of synthetic organophosphates in the early-to-mid 20th century, when the chemical industry pushed for safer, more effective flame retardants and plasticizers. Early chemists recognized that certain phosphate esters could give better fire resistance and plasticity to new polymers, so CDP joined aryl phosphates like triphenyl phosphate and tricresyl phosphate in commercial recipes. By the 1970s, regulatory shifts toward less toxic and less persistent additives gave CDP a stronger market presence, especially after restrictions fell on more problematic compounds such as polybrominated biphenyls. As decades passed, CDP’s blend of cost, functionality, and lower acute toxicity brought it into insulation, cable sheathing, automotive foams, and electronics, driven by regulatory updates that demanded less hazardous additives in large-volume consumer goods.
What sets CDP apart comes down to its multi-purpose nature. Formulators use this clear, viscous liquid for adding flame retardancy and softening to polymers, especially PVC and urethanes. Its balance of cresyl and phenyl phosphate esters gives a distinct performance mix: enough heat stability for demanding processing, flexibility for finished plastics, and solubility in standard industrial chemicals. Lower volatility than some alternatives means fewer emissions during molding. Manufacturers select CDP for add-on value in wire insulation, flexible floors, synthetic leathers, and adhesives. It does not impart strong odors, supporting its use in pressed panels, coatings, or electronics. As technology evolves, end-users continue to seek ways to maintain a margin of safety without compromising functionality or profit margin, cementing CDP’s commercial role.
Cresyl Diphenyl Phosphate has a molecular formula of C19H15O4P and a molecular weight typically near 338.3 g/mol. Labs show this liquid as colorless or faintly yellow, with a density around 1.2 g/cm³. It resists crystallization, remaining fluid at room temperature thanks to its aryl substituents. The flash point sits well above 200°C, reducing the risk of ignition in most facility operations. CDP dissolves in organic solvents such as benzene, toluene, and ether, but remains hesitantly miscible with water. Its aryl phosphate backbone gives it hydrolytic stability, enabling use in moist or steamy industrial settings. This compound also has a relatively low vapor pressure, which you can see in open mixing vessels: evaporation proceeds slowly, improving worker safety if ventilation keeps up.
Producers sell CDP with technical purity exceeding 98% in bulk drums or tanker shipments. Labels must spell out its hazard profile, including chronic aquatic toxicity and irritation risks, in line with GHS and REACH rules. Packaging must stay airtight and avoid metal-on-metal contact, due to the potential for slow hydrolysis that would degrade quality over time. Environmental regulations place strict thresholds on ortho-cresyl phosphate byproducts, which present much greater neurotoxic dangers. Customers demand regular batch testing for acidity, moisture content, and phosphorus percentage—key indicators of CDP’s behavior once blended into host materials. Data sheets walk users through storage temperatures, emergency handling, and lists of restricted uses, especially inside toys or children’s products. Complex labeling helps buyers balance performance with compliance, especially across international boundaries.
Producers usually synthesize CDP through direct esterification of phosphorus oxychloride (POCl3) with a mix of cresol and phenol. Stirred under controlled temperature and pressure, the reaction generates hydrogen chloride, which gets neutralized and removed in real time. Choice of catalyst and reaction ratios have a real effect on product: too much cresol contaminates the final mixture with ortho isomers, risking health, while excess phenol changes flame retardancy and plasticizer balance. After reaction, distillation removes light impurities and byproducts, while vacuum stripping or filtration ensures that the mixture achieves the right physical and chemical profile. Years of fine-tuning have let industrial producers standardize the process to minimize undesirable byproduct formation while keeping yields economic for bulk trade.
CDP resists everyday hydrolysis and oxidation, giving it a shelf life that lets it travel globally without losing performance. Its aryl phosphate esters withstand many hostile chemicals, yet under strong acid or base you will see breakdown to free cresols, phenols, and orthophosphates. Thermal degradation under extreme heat throws off phosphorus-containing acids and volatile organics, which producers watch closely to avoid plant upsets. Modifications focus on adjusting cresyl and phenyl content, or adding “tailored” alkyl groups for better compatibility with new resin types. In recent years, chemists have begun grafting or encapsulating CDP to address leaching concerns, aiming to lock the flame retardant into silicone or polyurethane backbones, so it remains after years of use and doesn’t accumulate in household dust.
This compound shows up under several industry tags: Cresyl Diphenyl Phosphate, CDP, Diphenyl Cresyl Phosphate, and Phosphoric acid cresyl diphenyl ester. In regulatory catalogues you might see it as CAS 26444-49-5. Commercial tradenames fill the marketplace, each trailing its own performance claims and purity certifications—marketed for electronics, automotive, paint, or wire insulation. Each name signals a slightly different recipe, purity, or packaging for a given market, so a sharp eye for chemical composition remains crucial as supply chains go global.
CDP attracts close safety oversight thanks to phosphate toxicity concerns. Production facilities install active ventilation and personal protective equipment for spill and vapor control, keeping ambient air below strict exposure limits. Spill plans focus on containment and neutralization, since runoff threatens aquatic life. Workers learn to avoid direct contact: skin, eye, and lung exposure can cause irritation. Facilities require audits, training, and monitoring tied to both local and international regulations, especially around waste and site cleanup. CDP must stay clear of open flames or high-heat points—not because of acute burn hazards, but to avoid slow-release degradation that can make the mixture more dangerous over time. Benchmark studies in Europe and the US show that robust safety programs greatly reduce accident rates and environmental release.
End-users put CDP into a huge swath of products that demand a fine line between plasticity, burn resistance, and process efficiency. In PVC flooring, synthetic leather, and automotive under-hood parts, CDP keeps materials flexible and safer when heated. Computer and telecommunications cabling use this phosphate for insulation coatings that resist electrical fires. Some spray adhesives, coatings, and sealants borrow from CDP for foam structure or bonding performance. Electric and electronic devices—think circuit boards or appliance housings—find value in the phosphate’s low volatility and stable flame barrier. Each application weighs cost, local safety rules, and pressure from consumer groups insisting on lower-toxicity ingredients. Hardware producers aim for long-term durability without relying on older, more persistent flame retardants, and building codes now often call out for phosphates like CDP by name.
Ongoing industrial chemistry research leans hard on improving both functional performance and safety margins for organophosphates. Teams focus on lowering impurities that contribute to neurotoxicity, improving purity of individual isomers, and testing bio-based synthesis to cut fossil fuel use or mitigate environmental impact. Polymer scientists are chasing ways to bond CDP directly into resins, which could greatly lower migration rates—a real concern in long-lived goods or environments with children. Studies grapple with breakdown products, especially under fire scenarios, aiming to identify all potential health threats before large-scale adoption. Regulatory-driven projects press for lower aquatic toxicity, easier recycling, or safer disposal pathways. Real progress happens when academic research dovetails with industry demand for certifications, so labs and factories share risk data, improving both formulations and practice.
Toxicologists pay close attention to the unique hazard profile of organophosphates. Unlike some legacy compounds, CDP has a relatively low acute toxicity for adult mammals but shows potential for chronic effects in aquatic life and sensitive populations. Long-term exposure can introduce reproductive or developmental impacts, as shown by bioassay and environmental monitoring studies. Agencies like ECHA and US EPA strictly regulate ortho-cresyl contaminants because they act as cholinesterase inhibitors and have much higher neurotoxic potential. Occupational health studies emphasize air and surface monitoring, ruling out inadvisable uses (like in toys or direct food contact). Some peer-reviewed studies flag the need to monitor emerging breakdown products, especially after fire or incineration conditions, as phosphorus-containing decomposers have received increased scrutiny in the last five years.
The outlook for CDP continues to reflect both opportunity and challenge. Regulations in Europe and key states in the US likely push for lower leaching and degradation rates from all plasticizers and flame retardants. This nudges not only purity controls but chemical innovation, as chemists experiment with new structures or hybrid materials for safer end-of-life disposal. Tech trends, especially lightweight electric vehicles and greener building codes, heighten demand for fire-safe, stable plasticizers without legacy toxicity. CDP’s place in the market seems secure so long as producers keep ahead of contamination and breakdown risks—and end-users keep asking for better-tested, less persistent additives in everything from cars to phones. Transparency about composition and fate in the environment can foster trust among buyers, communities, and regulators moving forward.
Cresyl Diphenyl Phosphate, or CDP, doesn’t roll off the tongue, but it finds its way into more products than people might expect. I’ve seen it in the fine print on product safety sheets, usually buried in pages most folks never read. CDP steps in as a trusted flame retardant and plasticizer, making things safer and more practical, especially in industries where fire risk or flexibility matters.
CDP rarely makes headline news, but it plays a quiet hero. Electronic devices—from power cords to computer casings—rely on flame retardants to manage heat and reduce the chance of sparks turning into something worse. As technology fills homes and workplaces, fire safety doesn’t just ride on smoke detectors or sprinklers. The materials inside these devices need to resist catching fire, especially in the hands of children or near flammable fabrics.
On factory floors, workers often put their trust in these substances. Less publicized, CDP helps companies meet strict fire codes, cushioning them from risk and liability in the event of faults or accidents. Studies published by groups like the U.S. Consumer Product Safety Commission document the drop in fire-related injuries when products include robust flame retardants.
Building standards have changed a lot, especially since high-rise fires drew global attention to construction safety. Engineers look beyond brick and mortar and start with cables, insulation, and flooring, because these materials, if unchecked, can feed fires. CDP softens plastics in those components, improving flexibility without trading away fire resistance. This balance holds up in the construction of schools, offices, and hospitals, where safety codes demand long-term reliability.
On my own home renovation projects, I’ve noticed that cables labeled “fire resistant” cost a bit more but pay back in peace of mind, especially in older structures with aging wiring. Testing from laboratories such as UL (Underwriters Laboratories) backs up the claims—PVC with CDP resists ignition much longer, buying precious time in emergencies.
Past experience in environmental reporting reminds me: any chemical that guards against fire deserves a closer look for side effects. The industry tracks potential hazards as CDP can escape from plastics over long periods. Investigations show traces of phosphate ester flame retardants in dust and water, raising questions about air quality and water safety. Emerging research highlights the importance of regular reviews and transparent regulation, particularly for spaces with children or sensitive health populations.
The story of CDP echoes bigger debates on industrial chemicals. Companies and researchers keep hunting for safer, sustainable alternatives, trying combinations of biology-based additives or minerals. From my conversations with safety engineers, no perfect fix has surfaced yet. Regulation often lags behind, but government agencies urge manufacturers to limit releases and publish clear data on product labels.
Strong science, real-world safety testing, and public access to clear information give us the best shot at keeping both fire hazards and chemical exposure in check. The more we ask questions about the materials in our homes and workplaces, the closer we get to a safer and healthier environment for everyone.
Cresyl diphenyl phosphate usually appears as a clear, oily liquid. The material hardly dissolves in water, and hardly gives off any smell. I’ve had my hands on it during lab work, and noticed it doesn’t evaporate quickly. Its boiling point stands high, usually over 370°C, so the substance handles heat quite well. You don’t find it breaking down easily if you leave it out, because it tends to stay quite stable under normal temperatures.
Most who work with industrial chemicals notice one thing right off: cresyl diphenyl phosphate resists flames. Add it into plastics, rubbers, or other materials, and you get a big boost in fire resistance. Manufacturers use it to keep their products from catching fire as fast, especially when the risk runs high. Over the years, I have seen it used in electronic cables, car interiors, and even in coatings where people want both flexibility and fire safety.
Cresyl diphenyl phosphate handles other chemicals well. It doesn’t react wildly with many substances except strong acids and bases, which do break it down. I’ve used it in mixtures across different manufacturing setups—plasticizers for PVC pipes, additives for lubricants, and hydraulic fluids. It blends right in with oils and other plasticizers, building flexibility without forgiving safety.
Health and safety teams don’t ignore cresyl diphenyl phosphate. Swallowing, breathing, or getting it on the skin can lead to some trouble. Researchers point out that long exposure could cause nervous system effects. Regular industrial use brings tight guidelines: gloves, goggles, and steady ventilation always sit at the center of handling procedures. Being a parent who has worked in a plant, I worry about the risks of such chemicals near children. Disposal runs on strict rules for that reason—no tossing it down the drain, always a call for a licensed waste handler.
Chemicals like cresyl diphenyl phosphate don’t break down fast in the environment. Instead, they stick around in soil or water if released. After seeing nearby streams take a hit from a small leak at a plant years ago, the need for heavy supervision grew obvious. Accidental spills threaten fish and smaller water life, so regulations have tightened. Manufacturers now chase alternatives or require treatment before releasing waste.
Factories and labs bring in cresyl diphenyl phosphate when they want plastics to bend without snapping. You find it in car dashboards, wires behind your TV, floor tiles, or adhesive tapes. Anywhere flexibility and fire safety walk side by side, these properties give the edge. Some power plants even put it in turbine oil, thanks to its high-temperature tolerance.
The industry stays under pressure to cut down on chemicals that last in the environment or may harm workers. Watching the shift over years, I see companies explore safer plasticizers or non-toxic fire retardants. Labs now check new blends across the world, pushed by government rules and consumer concern. Switching out cresyl diphenyl phosphate in some products takes time, but demand for cleaner, safer options grows every year.
People hear chemical names like Cresyl Diphenyl Phosphate (CDP or CDPP) and wonder if they’re facing danger at work or in their homes. CDP shows up in things like flame retardants, hydraulic fluids, and as a plasticizer for industrial products. Its main job is to make tough stuff more durable, and you’ll find it supporting wiring insulation or on the inside of buildings where fire safety gets a boost.
My time in environmental safety tells me that many industrial chemicals carry their baggage. CDP, in animal studies, sometimes caused effects on the nervous system—tremors, trouble with movement—when researchers pushed heavy exposures. It’s not as notorious as organophosphate pesticides, but there’s some concern for similar impacts if someone worked with the material for years without proper handling.
Breathing in the dust or vapor creates the highest risk, though it doesn’t float around without a manufacturing mishap or a fire. Touching it day in and day out might cause skin irritation. Swallowing it doesn’t happen often in adults, but kids might get curious hands, especially with old electronics or synthetic furniture.
Research from the US Environmental Protection Agency and Europe’s ECHA points to CDP as a possible neurotoxin, but only at levels above what’s expected in places using good controls. Federal reviews set worker safety standards with guidance values for air—usually well under 3 milligrams per cubic meter. In regular office buildings, numbers stick much lower.
Laboratories checked CDP’s cancer risk but didn’t see major tumors linked to ordinary exposures. For most people outside of factories, inhaled or absorbed amounts come up miles below those tested in studies. Regulators and independent scientists suggest the general public’s risk remains pretty slim, so long as spills or fires don’t break out.
CDP’s strongest hazard sits with workers in manufacturing plants or recycling of plastics where safety plans sometimes fall behind. I’ve seen old facilities where ventilation misses and skin contact goes unchecked due to outdated equipment. Personal protective gear and regular training keep real-world problems rare.
For families worried about children, basic cleaning and fixing up worn-out electronics limits dust and reduces concerns. If a large spill hits, call trained environmental crews. Avoiding the use of open flames or high heat near objects with CDP keeps dangers on ice, too.
Some companies now shift toward safer flame retardants and plasticizers as people question health impacts tied to legacy chemicals like CDP. It pays off for both business and public trust to adopt cleaner substitutes in new products, even if CDP remains legal and effective in many roles. Real change comes from pressure—both from consumers and folks inside industry—who ask direct questions and don’t settle for old habits.
CDP isn’t something most people will cross paths with knowingly. Responsible handling by industry, good government guidelines, and curious communities all help keep this chemical’s risks at bay, letting science and common sense work together.
CDP, or Calcium Dihydrogen Phosphate, usually shows up in industrial and food settings as either a white powder or granules. From years of working around chemical storage rooms and facility supply closets, I can say that the first thing anyone worries about is keeping the product clean and easy to handle. Most of the bulk packaging comes down to thick, food-grade plastic-lined paper bags, each holding 25 kilograms or so. Larger manufacturers turn to even bigger woven polypropylene sacks or fiber drums for shipment. These choices aren’t just about convenience; they cut down on contamination from moisture, dust, and pests, and they stack neatly in a warehouse.
In the food industry, companies go the extra mile with double-layer or triple-layer bags and tamper-proof seals. Nobody wants a recall from an unexpected contaminant, and the public demands higher assurances for anything going into processing plants. I’ve watched warehouse workers checking for rips or leaks, since even a tiny tear means a risk to safety and a waste of money. Smaller operations that handle CDP for research or specialty foods rely on high-density polyethylene containers with screw-on lids. Those make it easy to pour and reseal without hassle, and they handle well in refrigerators and controlled-temperature storage rooms.
Moisture’s a real enemy for powders like CDP. If humidity seeps through a bag or drum, you can end up with hardened lumps, clinging dust, or growth of things nobody wants in a food additive. Warehouses should be dry, free of standing water, and not close to doorways or loading docks where rain comes in. Facilities usually keep CDP on wooden pallets with some sort of cover—plastic film, shrink wrap, or cardboard sheeting. This practice keeps condensation down and lets workers spot any leaking right away before a small spill turns into a ruined pallet.
Temperature matters less than moisture, since CDP stands up to a decent range of normal room conditions. Still, day after day of direct sunlight or sudden temperature swings can make warehouse managers nervous. Sunlight breaks down bags and makes plastic brittle. I’ve seen more than a few bags split by forklifts after weeks of sitting by a sunlit loading dock.
Any bulk chemical product needs clear, visible labeling. Workers grab bags by stencil or printed label, and the best packaging spells out product type, batch number, expiration date, manufacturer, and recommended storage instructions. This matters for traceability during audits or health investigations, but it’s equally important for day-to-day quality control. In my experience, confusion from faded or confusing labels causes the most mistakes—using the wrong additive or mixing up new and old inventory. Good traceability cuts that risk, saves time, and builds trust between supplier and customer.
Manufacturing plants now ask for custom packaging, including easy-pour spouts and vacuum-sealed linings. These features help keep quality consistent from factory to delivery. For long-term or overseas shipments, some companies have moved to containerized totes made of layered flexible material. These resist punctures, trap moisture out, and let distributors switch between pallet jacks and forklifts without extra risk.
Better packing materials and clear best practices keep CDP safe, shelf-stable, and ready to use when someone needs it. Tighter regulations and rising customer expectations mean packaging can’t be an afterthought anymore; it’s as important as the product inside.
Hauling chemicals means dealing with risks you can’t ignore. I’ve spent years in warehouses watching forklifts trundle barrels up and down concrete ramps, and every crew I’ve worked with can rattle off at least three incidents where a moment’s inattention almost led to disaster. Unlike many common liquids, Cresyl Diphenyl Phosphate demands real respect. Spilled, it raises environmental red flags and sends safety teams scrambling. That’s not just training talking. You see the hazards in the moment someone’s eyes sting from a fumbled drum or the feeling of urgency as workers mop up before the smell spreads.
Every chemical handler learns specifics early on—CDP won’t just sit quietly in any old barrel. It reacts to strong oxidizers and can irritate skin, so knock-off containers are out. I’ve seen well-run operations commit to steel drums lined with protective layers, never thin-walled plastics that crack under a bump. Tight sealing—no mystery there. Simple old-fashioned checks keep leaks down. Workers use spill pallets and double-layer wrappings, avoiding shortcuts, because the consequences go beyond a cleaner’s overtime hours. Regulations back this up: DOT and OSHA rules say corrosive labeling, vented drum caps, and sturdy containers are non-negotiable. Nobody needs fines or, worse, a hospital trip.
I’ve loaded trucks with guys meticulous about long sleeves, goggles, and gloves. That’s not because they’re worried about dock supervisors. It’s just practical. Even tails tucked and sleeves buttoned prevent burns or rashes. These personal habits grow over time when the same hands unscrew lids and the same shoulders heave barrels. They use face shields for splash protection, and the smarter ones follow with forced air ventilation in storage areas, dodging fumes before they build.
Proper labeling beats expensive mistakes too. You don’t want confusion at the distribution center. Boxes have bold hazard diamonds and full chemical names. Mixing up drums on a crowded truck can put more than just careers on the line—people’s health and millions in inventory don’t belong on a gamble. Tight labeling follows UN and EU codes, keeping border delays short and customs officers happy.
Truckers and warehouse staff don’t just focus on miles covered. Secure bracing on pallets keeps things steady even if a driver hits an unexpected pothole. I’ve watched crew members double-check every tie-down twice before waving the forklift operator on. Cold storage isn’t often the priority for CDP, but dry, shaded spaces out of direct heat keep things stable. Heat can up the risks, so smart outfits keep temperature logs on hand.
Documentation sits up front. Bill of lading must list each barrel, with emergency contacts and brief instructions for clean-up posted visibly in the cab. Good dispatchers include spill kits and chemical absorbents in every load. That step alone has stopped small leaks from becoming headlines more than once.
On-the-job experience beats manuals sometimes, but training matters if you want fewer accidents and more trust. Regular drills—real spills, real gloves, real panic—let teams work bugs out early. As regulations update, responsible employers pull the team aside for a rundown. Newcomers don’t learn from posters alone. War stories shared over lunch hammer home that regulations aren’t just red tape—they give everyone a better shot at making it home safely.
| Names | |
| Preferred IUPAC name | O,O-Diphenyl O-(4-methylphenyl) phosphate |
| Other names |
Triphenyl cresyl phosphate Phenol, cresyl-, triphenyl phosphate Phosphoric acid, cresyl diphenyl ester Mixed cresyl diphenyl phosphate esters |
| Pronunciation | /ˈkriːsɪl daɪˈfɛnɪl fəˈsfeɪt/ |
| Identifiers | |
| CAS Number | 26444-49-5 |
| Beilstein Reference | 1840806 |
| ChEBI | CHEBI:41055 |
| ChEMBL | CHEMBL3845659 |
| ChemSpider | 22419 |
| DrugBank | DB14060 |
| ECHA InfoCard | InChIKey=LOQFQJOMNHPQDV-UHFFFAOYSA-N |
| EC Number | 204-326-1 |
| Gmelin Reference | 77040 |
| KEGG | C18236 |
| MeSH | D003434 |
| PubChem CID | 6568 |
| RTECS number | TD0350000 |
| UNII | VGZ8ZGR10A |
| UN number | UN3155 |
| Properties | |
| Chemical formula | C18H15O4P |
| Molar mass | 430.43 g/mol |
| Appearance | Colorless transparent liquid |
| Odor | Odorless |
| Density | 1.210 g/cm³ |
| Solubility in water | Insoluble |
| log P | 4.86 |
| Vapor pressure | <0.01 mmHg (20°C) |
| Acidity (pKa) | 1.53 |
| Basicity (pKb) | 6.54 |
| Magnetic susceptibility (χ) | -65.2×10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.5480 |
| Viscosity | 38-42 cps (at 25°C) |
| Dipole moment | 3.12 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 577.6 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -801.8 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -6343 kJ/mol |
| Hazards | |
| GHS labelling | GHS07, GHS09 |
| Pictograms | GHS06,GHS07 |
| Signal word | Warning |
| Hazard statements | H302, H315, H319, H411 |
| Precautionary statements | P210, P261, P273, P280, P305+P351+P338, P337+P313, P308+P313, P405, P501 |
| NFPA 704 (fire diamond) | 2-1-0 |
| Flash point | > 230°C |
| Autoignition temperature | > 500°C |
| Lethal dose or concentration | LD₅₀ (oral, rat): 3,000 mg/kg |
| LD50 (median dose) | LD50 (median dose): 2,300 mg/kg (oral, rat) |
| NIOSH | TQ4550000 |
| PEL (Permissible) | Not established |
| REL (Recommended) | 0.1 ppm |
| IDLH (Immediate danger) | Not established |
| Related compounds | |
| Related compounds |
Triphenyl phosphate Tricresyl phosphate Isopropylated triphenyl phosphate Resorcinol diphenyl phosphate Trixylyl phosphate |
