Resorcinol bis(diphenyl phosphate), often shortened to RDP, really kicked off in the world of flame retardants during the late twentieth century, right around the time when people realized that halogenated flame retardants left unwanted legacy problems in the environment. Scientists started experimenting with aryl phosphate esters, tapping into the strengths of resorcinol, for better heat resistance and lower smoke production. Early development saw big names in chemistry like Monsanto and ICI racing to engineer safer alternatives to traditional materials. The rise of stricter fire safety codes in North America and Europe built a real sense of urgency, setting the stage for RDP to step in and get the job done in electronics, polymers, and coatings.
RDP stands out by mixing good flame retardancy with reliability in performance plastics and coatings. Unlike some options with messy side effects, RDP gives less smoke and toxic gas during burning, which can make a big difference during real-life fires. In the manufacturing world, it allows fine-tuned handling and compatibility with key polymers like polycarbonate (PC), acrylonitrile butadiene styrene (ABS), and polyvinyl chloride (PVC). The industry welcomes its liquid state at room temperature and its ability to blend into formulations without a hitch. This chemical combines robust engineering benefits with growing environmental demand for halogen-free options.
Resorcinol bis(diphenyl phosphate) commonly appears as a viscous, colorless to pale yellow liquid. It brings a density of about 1.18 g/cm³, a relatively high boiling point nearing 410°C, and it refuses to dissolve in water—a feature that prevents leaching. Its molecular structure, C30H24O8P2, features a resorcinol core bridged by diphenyl phosphate groups, giving it not just heat stability but also resistance against hydrolysis under normal storage. This mix produces a flash point above 230°C, supporting safer storage and transport compared to many historic flame retardants.
Quality RDP products must meet industry benchmarks for purity, phosphorus content, acid value, viscosity, and thermal degradation temperature. Regulatory compliance shines through in the labeling: GHS pictograms, UN shipping codes, and detailed handling guidelines all fall under requirements for shipping across state and national borders. Many suppliers in the US and Europe also tout REACH registration and RoHS compliance to give manufacturers confidence for sensitive electronics or children’s products. Strict batch testing looks for trace metals, organophosphorus impurities, and volatile organic content to satisfy both performance and regulatory demands.
Manufacturers turn to direct esterification, which joins resorcinol with diphenyl chlorophosphate in the presence of acid scavengers (like triethylamine) and solvents, usually under anhydrous conditions. This method demands careful attention to time, temperature, and pH control. After reaction, purification steps (washing, phase separation, vacuum distillation) remove hydrochloric acid and unused reactants, making sure the final product comes out as pure as possible. Any shortcut in this part can quickly degrade quality or lead to unwanted byproducts. Plants devote real investment to closed systems and air treatment, reflecting both worker safety and environmental stewardship.
RDP’s phosphate esters make it a flexible building block in chemical synthesis. It resists most hydrolysis unless hit with strong acids or bases, widening its applications. Companies experiment by tweaking the backbone or replacing the phenyl groups to dial in custom flammability resistance or workability. In certain projects, partial hydrolysis creates oligomers for controlled migration or reactivity. Strong oxidizers may break down the aromatic rings, but under normal processing conditions, RDP keeps its integrity, which is vital for performance in thermoplastic blends.
Chemists use a few different names for resorcinol bis(diphenyl phosphate): RDP, bisphenol phosphate, and the CAS number 57583-54-7. Product names depend on the supplier—examples include Fyrolflex RDP (ICL), CR-733S (IC&C), and BDP (for structurally similar compounds). It crops up under various trade names in plastic compounding catalogs, but the molecular base remains the same. Knowing these terms helps engineers and safety managers track certifications and match product types across regions.
Direct contact with RDP may cause irritation to the eyes, skin, and respiratory tract, though risk remains lower than many halogenated counterparts. Chronic exposure presents habitat risks if spilled in waterways. Plant operators follow established procedures: closed transfer systems, routine glove and goggle checks, and spill containment protocols, based on local occupational safety standards. Globally, producers must keep up with OSHA, EU REACH guidelines, and strict documentation for transport. Emergency data sheets provide clear firefighting instructions and toxicology information. Regular audits and environmental monitoring keep the chemical’s handling rooted in best practices.
RDP serves a broad base as a flame retardant in electronics housings, automotive components, and flexible PVC products. It’s especially valued in the tech sector, where laptops, televisions, and smartphones demand both fire resistance and clean environmental profiles to pass global certifications. You see it in rigid foams for construction, cable insulation, and some adhesives. Because of the low volatility and high compatibility, manufacturers appreciate it in injection molding and extrusion processes where smoke production can gum up the works. Research teams test blends for everything from medical devices to public transport materials to push safety standards forward.
R&D teams take much of their energy from the pressure for safer, greener flame retardants. Labs publish studies on blending RDP with other phosphorus compounds or nanomaterials that further dial down smoke and toxicity but keep the price in check. Materials scientists unlock new synergies between RDP and recycled plastics, meeting sustainability goals for circular economy-minded clients. Safety testing figures big in this field—one misstep puts lives and brand reputations at risk. Research journals dive into the environmental breakdown of RDP, with growing knowledge allowing stricter, evidence-driven decision-making by regulatory bodies and purchasing managers.
RDP offers a lower acute and chronic toxicity profile than older halogenated options, but it’s not risk-free. Animal studies show low bioaccumulation and metabolization rates, with clearance mainly through excretion, rather than building up in fatty tissues. That reduces the risk for long-term poisoning, but aquatic toxicity keeps regulators watchful. RDP’s byproducts under fire conditions include phenol derivatives and some phosphoric acid compounds—most far less harmful than dioxins or furans, but not entirely benign. Countries set discharge limits and require constant monitoring. Transparent reporting and open access to health data help prevent problems from slipping under the radar.
Future demand will likely rise as new sectors, such as electric vehicles and energy storage, hunt for fire-safe, lightweight housing materials that tick green chemistry boxes. Consumers and regulators both push hard for halogen-free, low-smoke, sustainable substances—a trend that makes RDP a fit for big-ticket uses. Companies explore routes to bio-based resorcinol and greener phenol feedstocks, drawing on a shift toward cradle-to-cradle chemistry. Regulations keep moving—REACH requirements tighten year by year, raising the bar for safety tests and environmental proof. For researchers, tracking and improving RDP’s lifecycle impacts will shape the next wave of innovation in both chemical engineering and product design.
Ask anyone who’s lived through a big fire and they’ll tell you: slowing flames buys time. Once flames start, every extra second matters. That’s where resorcinol bis(diphenyl phosphate)—often called RDP—steps in. It doesn't draw headlines, but it’s found in electronics, car interiors, and building materials. It’s not about melting into a product and calling it a day. RDP acts as a flame retardant, which means it slows how quickly materials light up and burn. For materials like plastic, especially the types wrapped around wires or used in computer parts, catching fire quickly puts lives and property at risk.
I’ve seen what can happen when safety gets overlooked in cheap devices—plastics that melt, wires that spark. Manufacturers want plastics to be flexible and tough, but those qualities often mean a fire moves fast once it starts. RDP interrupts that process. It’s mixed into plastics, not just coated on the outside. When the plastic heats up, RDP releases compounds that interfere with the combustion process. Simple idea, big protection.
Electronic gadgets and their chargers rely on this. Televisions, power strips, servers in busy data centers—there’s a silent safety net at work. Polycarbonate is a favorite material for these uses because it’s strong and clear, but it’s also stubbornly flammable unless blended with something like RDP. RDP helps keep products clear instead of yellowing (some flame retardants cause this problem).
Fire safety used to rely on chemicals called PBDEs, but these built up in the environment and in people—nobody wants toxic leftovers at home. Regulators in Europe and the U.S. started banning those, which pushed the industry toward alternatives. RDP isn't perfect, but it doesn't build up the way PBDEs do. Studies so far show less risk to health and less trouble for the food chain.
The conversation gets tricky here. Every chemical shield against fire brings trade-offs. Old-school approaches gave us breathing problems and toxic dust. RDP is a step in the right direction. Still, people keep asking tough questions: Do safer chemicals really cover every risk? Should we rethink how much plastic we surround ourselves with? I’ve worked in spaces where you can see the cost of shortcuts—cheap cable insulation, furniture stuffed with flammable foam. Each new fire makes policymakers think again about building codes and allowed ingredients.
Some see RDP as a temporary fix, not a final answer. There’s work happening in labs—engineers trying clay nanocomposites or even plant-based barriers. Companies test new blends to balance fire resistance, durability, and recycling. Building safer homes, cars, and devices will take persistence and honest talk about trade-offs. Fire safety doesn't shout for attention, yet nearly everyone trust the furniture, gadgets, and cars around them to stay safe in case of sparks. RDP keeps working quietly, holding back the flames. It’s not glamorous, but it buys time—sometimes just enough.
Resorcinol Bis(Diphenyl Phosphate), known to chemists and manufacturers as RDP, shows up in flame retardants and some plastic products. Anyone who works in materials science or industrial labs probably recognizes the chemical by its sharp, slightly phenolic odor and greasy consistency. Research labs and industry ask tough questions about its effects. Workers deal with it up close, so the safety conversation isn’t some distant matter for experts—it's daily reality for a lot of people.
Gloves, goggles, and fume hoods fill every safety manual that mentions this material. People who handle RDP tell stories about headaches, shortness of breath, and skin irritation after accidental exposure. Toxicologists have pointed out that RDP can lead to both skin and eye irritation. According to the European Chemicals Agency, the stuff also poses environmental risks—especially around waterways. RDP doesn't just pack up and leave once spilled. It can linger in water, putting aquatic organisms under stress.
Sometimes the conversation lands on what long-term exposure to organophosphates like RDP does to human health. Animal studies have worried scientists for years, with links to hormone disruption and developmental problems at high doses. RDP doesn’t have the same notoriety as some pesticides, but the chemical structure fits a pattern of concern. The Occupational Safety and Health Administration in the US, and their EU counterparts, have not established specific exposure limits for RDP, but treat it as a possible irritant and ask employers to adopt tight controls in its handling.
Anyone who has spent time in a processing plant or R&D site knows safety culture sets the tone. Training goes a long way to keeping workers out of harm’s way—so do engineering controls. Spill kits and ventilation matter just as much as lab coats. People should never take shortcuts or trust that a compound is “probably fine” if the science hasn’t pinned down every effect. Supporting this, major polymer manufacturers offer real-world case studies reporting that good practice—regular health checks, air monitoring, strong PPE—keeps exposure low and incidents rare.
For smaller businesses or labs that may not always keep up with the latest research, sharing updated guidance and access to resources makes a big difference. Preventing inhalation and direct skin contact takes better planning in places with limited funding or older equipment—places where corners sometimes get cut.
People sometimes ask why industries use RDP instead of safer alternatives, since there’s always another flame retardant on the shelf. Companies often say cost, fire performance, and material compatibility sway their decisions. Regulatory review lags behind chemical innovation too, which means even cautious managers might miss a hazard until more studies emerge.
Transparency helps everyone—workers, consumers, and the environment. Some companies now invite third-party audits or publish the safety data they gather, hoping for better trust. Governments and researchers can push for more rigorous studies, especially on chronic exposure and environmental behavior. With new lab techniques and more data sharing, the mysteries behind chemicals like RDP might not last much longer.
Plenty of folks in chemical manufacturing remember times when substances once thought routine turned out risky. RDP doesn’t seem to belong to the “most hazardous” group, but it isn’t harmless either. Practical safety steps—decent ventilation, responsible chemical storage, and reliable protective gear—will keep risk in check. As science fills in the blanks, those on the front lines should take each new warning seriously, and push for safer ways to do their jobs. A safer workplace grows from real stories, solid data, and a stubborn refusal to overlook small but important risks.
I’ve come across Resorcinol Bis(Diphenyl Phosphate), or RDP, quite a few times working on materials that need to limit fire risk. The first thing people notice with RDP is its strong performance as a flame retardant, especially in plastics and foams found in electronics and construction materials. Chemists often point to the high phosphorus content in RDP. This element slows down combustion and helps form a protective layer on the surface when things heat up. That’s a huge deal for safety in consumer products.
RDP flows as a viscous, clear liquid at room temperature. You don’t have to squeeze it into a shape or dissolve it in exotic chemicals—just pour and mix. That liquid state makes processing more straightforward in manufacturing. Unlike some flame retardants, RDP brings low volatility. Off-gassing and emissions tend to worry folks who care about workplace safety or indoor air quality, but RDP generally stays put, even under pressure from heat.
Not every flame retardant pairs well with plastics like polycarbonate or ABS. RDP plays well with many types, including the blends used for laptop housings, circuit boards, and wiring insulation. That’s a big plus—an additive that wrecks durability or makes a product brittle won’t last long in an engineer’s toolkit. Decades of research support the idea that RDP helps retain impact strength, clarity, and stability in products. The electronics industry, in particular, leans heavily on RDP for meeting fire safety norms without compromising device toughness.
People ask me about toxicity and environmental persistence. RDP stands out because it’s free from halogens like chlorine or bromine, which regulators across the world target due to persistent pollution and bioaccumulation. Halogen-free chemistry has helped companies keep up with stricter rules in the European Union, North America, and Asia. But RDP hasn’t escaped scrutiny; it breaks down slowly, and some downstream products may cause concern for aquatic life. Routine monitoring under REACH and other regulatory bodies aims to limit risks, and manufacturers take steps to limit exposure.
On a practical level, RDP doesn’t present extreme storage headaches, provided facilities keep it in sealed containers away from moisture. Prolonged contact with water triggers hydrolysis, which can lead to performance drops or side products not desired in the mix. Facilities set up workflows to use up inventory steady and avoid leftover stock.
Sustainability remains a challenge for all fire retardants, not just RDP. Continued research into less persistent replacements matters for both industry and end users. Until a widely available green substitute emerges, careful lifecycle management, effective recycling of RDP-containing materials, and transparent labeling help lower long-term risk. Scientists and engineers collaborating with regulators and recyclers have the best shot at driving progress without backsliding on product safety.
Dealing with specialty chemicals like Resorcinol Bis(Diphenyl Phosphate) (RDP) does not have to weigh on the mind. Many people imagine stacks of technical manuals and warning signs, but the reality on the ground means managing a balance between precaution and common sense. Having worked closely with chemical stockrooms during my time in an industrial lab, I know how small storage choices can make a major impact. This chemical holds real value as a flame retardant in things like electronics and building materials, so learning how to manage it properly is worth the attention.
Storing RDP in a space away from direct sunlight keeps the liquid from breaking down before its time. I recall a shipment left under a skylight—one week of harsh sun changed the chemical’s color and cut its shelf life. Even small temperature swings can nudge the liquid out of its stable state, and in my experience, constant room temperature worked best. Fluctuations between warm and cold air led to condensation inside drums, introducing both water and corrosion. Moisture always finds a way, so a dry area is not just a bonus—it saves money and headaches.
RDP usually comes packed in lined drums or plastic containers. Opening and closing those lids with care means the contents stay uncontaminated. During weekly storage scans at my previous job, I’d always notice that loose lids or cracked seals led not just to ruined chemicals but also to workplace hazards. A good seal prevents outside air from clouding or affecting the contents, stopping slow chemical changes or outright degradation. There’s no substitute for regularly checking containers for leaks and tight fits.
One lesson from my years managing stock: mixing chemicals with unknown neighbors always ends badly. RDP gets along poorly with strong acids, bases, and oxidizers. A quick shelf check solves a lot of problems—one misplaced bottle could set off a chain reaction if things spill. Keeping RDP in its own spot, away from volatile substances, limits the risks of fire or unexpected reactions. These small actions protect the people handling the material, along with the building and equipment.
During audits, tracking not just the lot number but also date of arrival and who last used each drum added more than paperwork—it sped up recalls and trimmed waste. I found that clear labeling stopped coworkers from mistaking RDP for lookalike liquids. Even good intentions can go wrong if people don’t know exactly what they’re grabbing. Big, clear labels and up-to-date records gave everyone a sense of control and safety.
Having the right spill kits, absorbent pads, and cleanup procedures nearby matters as much as any label or lock. Training staff to respond quickly created a sense of teamwork in our lab. Posting key storage rules—temperature range, moisture limits, no-mix neighbors—right on the storage area door turned theory into practice. No system is perfect, but by sharing experiences and learning from close calls, groups can avoid repeating mistakes. Routine reviews, swift cleanup after leaks, and open communication solved more problems for our team than any high-tech sensor or alarm.
By handling RDP with respect—cool, dry, separate, and labeled—we protect more than just the chemical itself. We keep people out of harm’s way. Based on years in labs and storerooms, these simple steps keep operations running safer and smoother.
Resorcinol Bis(Diphenyl Phosphate), often found under the abbreviation RDP, shows up in quite a few places where flammability poses a real daily threat. The plastics industry often relies on this compound to hold back flame spread, especially in electronics housings and construction materials. Polycarbonate blends become safer with RDP. It allows manufacturers to meet fire codes without having to change much about how they actually build their products. From personal experience working with materials for home appliances, I’ve seen RDP become indispensable for passing safety inspections for toasters, hair dryers, and other devices that combine heat with plastic cases. The alternative means risking product recalls or melted plastics—and no company wants that trouble.
The electronics sector keeps RDP in steady demand. Printed circuit boards need protection against short circuits and high temperatures, which can otherwise spark a fire in a hurry. Plenty of consumer gadgets would not meet safety regulations without flame retardants like RDP integrated into the laminate or casings. Data centers and server racks use RDP-treated panels and wire coatings because a small fire can quickly turn disastrous in rooms filled with electronics. Industry data from regulatory bodies back this up—it’s not just a matter of opinion. More devices indoors means a greater need for robust flame resistance all down the supply chain.
Car interiors include more polymers now than ever. Dashboard panels, wire harness coatings, seat foam, and even headliners incorporate RDP to slow down or stop flames from spreading after an electrical fault or car accident. In my years interacting with auto repair shops and manufacturers, techs often mention changes to wire insulation standards and interior trim codes. RDP’s inclusion helps automakers meet regulatory targets for both passenger safety and insurance ratings. With electric vehicles rolling in, the importance of keeping wires cool and safe only climbs higher.
Construction jobs frequently involve adhesives, sealants, and foams that double as barriers and gap-fillers. RDP gets blended into these products to add fire resistance in walls, ceilings, and HVAC components. Anyone in the trades—builders, carpenters, HVAC professionals—knows building codes change with every update. After one customer’s renovation project, I saw firsthand how inspectors checked for fire-retardant materials in sealant beads around wiring and pipes. Homeowners sometimes skip these details, but pros don’t take chances, especially in multi-unit projects or public spaces. RDP delivers a safety layer that meets local and national code requirements, something no builder can neglect.
The key reason industries turn to RDP lies in the push for halogen-free flame retardants. Older chemicals sometimes created toxic fumes when burned. RDP marks a shift toward safer options. Studies from the EPA and similar bodies show lower emissions of hazardous byproducts from RDP-based materials in fires. Some critics point to questions around persistent organic pollutants, but as regulations tighten, producers and customers continue to look for transparent testing, better labeling, and ongoing research into health implications. More companies now offer alternatives that blend RDP with bio-based ingredients or recycled plastics in an attempt to further reduce risks.
Industry groups work with researchers to improve flame-retardant options every year. Efforts go into refining RDP for easier recycling, lowering toxicity, and boosting overall effectiveness. Companies can invest in employee training for safe handling and stay engaged in discussions about future regulatory shifts. Governments should keep supporting independent testing, so buyers trust what they install in their homes, cars, or offices. Although no single flame retardant fits every scenario, thoughtful use of RDP in the right place means safer products and fewer risks, especially as the world demands greater transparency and sustainability.
| Names | |
| Preferred IUPAC name | Bis(diphenyl phosphate)benzene-1,3-diol |
| Other names |
RDP Isopropylidenediphenol bis(diphenyl phosphate) Bisphenol A bis(diphenyl phosphate) Bis(diphenyl phosphate) resorcinol |
| Pronunciation | /riˌsɔːrsɪˌnɒl bɪsˌdaɪˈfiː.nəl ˈfeɪs.feɪt/ |
| Identifiers | |
| CAS Number | 125997-21-9 |
| 3D model (JSmol) | `"3D model (JSmol)" string for Resorcinol Bis(Diphenyl Phosphate": ` ``` P(Oc1ccccc1)(Oc2ccccc2)Oc3ccc(Oc4ccccc4)cc3 ``` *(This is the SMILES string that JSmol accepts for rendering the 3D model of Resorcinol Bis(Diphenyl Phosphate).)* |
| Beilstein Reference | 2558733 |
| ChEBI | CHEBI:81343 |
| ChEMBL | CHEMBL4299862 |
| ChemSpider | 10619976 |
| DrugBank | DB13903 |
| ECHA InfoCard | ECHA InfoCard: 100.108.400 |
| EC Number | 248-437-0 |
| Gmelin Reference | 74254 |
| KEGG | C18562 |
| MeSH | D017065 |
| PubChem CID | 197296 |
| RTECS number | TB6130000 |
| UNII | 8B1Q2SF4ZS |
| UN number | UN3272 |
| CompTox Dashboard (EPA) | DTXSID0024175 |
| Properties | |
| Chemical formula | C36H27O8P2 |
| Molar mass | 696.56 g/mol |
| Appearance | White to Off-white Powder |
| Odor | Odorless |
| Density | 1.302 g/cm³ |
| Solubility in water | Insoluble |
| log P | 1.6 |
| Vapor pressure | <0.01 mmHg (20°C) |
| Acidity (pKa) | 1.13 |
| Basicity (pKb) | 7.15 |
| Magnetic susceptibility (χ) | \-74.0·10⁻⁶ cm³/mol |
| Refractive index (nD) | 1.558 |
| Viscosity | 500–700 mPa·s |
| Dipole moment | 4.06 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 774.6 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -1764.8 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -5734 kJ/mol |
| Hazards | |
| Main hazards | Causes serious eye irritation. |
| GHS labelling | GHS07, GHS09 |
| Pictograms | GHS07, GHS09 |
| Signal word | Warning |
| Hazard statements | H302, H319, H332 |
| Precautionary statements | P210, P273, P280, P305+P351+P338, P308+P313 |
| NFPA 704 (fire diamond) | 2-1-0 |
| Flash point | 279°C |
| Autoignition temperature | 485°C |
| Lethal dose or concentration | LD50 (oral, rat): > 2000 mg/kg |
| LD50 (median dose) | LD50 (median dose): >2,000 mg/kg (rat, oral) |
| NIOSH | TTZ005 |
| PEL (Permissible) | Not established |
| REL (Recommended) | 0.1 mg/m3 |
| Related compounds | |
| Related compounds |
Triphenyl phosphate Bisphenol A bis(diphenyl phosphate) Tris(2-chloroethyl) phosphate Tetrakis(hydroxymethyl)phosphonium chloride 2-Ethylhexyl diphenyl phosphate |
