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Phenol, 4,4'-sulfonylbis- is a symmetrical aromatic diol commonly known as Bisphenol S.
Phenol, 4,4'-sulfonylbis- contains two para-hydroxyphenyl rings connected by a polar sulfone bridge, providing a rigid and thermally stable structure.
Phenol, 4,4'-sulfonylbis- is used primarily as a reactive monomer, chemical intermediate, thermal-paper developer, dye-related auxiliary, and analytical reference material.
CHEMICAL IDENTITY AND COMMON NAMES
Phenol, 4,4'-sulfonylbis- belongs to the bisphenol and aromatic sulfone chemical families.
The two phenolic hydroxyl groups provide bifunctional reactivity, while the electron-withdrawing sulfone group increases acidity, polarity, molecular rigidity, and melting temperature.
Phenol, 4,4'-sulfonylbis- is structurally distinct from Bisphenol A, Bisphenol F, diphenyl sulfone, 4,4'-thiodiphenol, and 2,4'-sulfonyldiphenol.
The 2,4'-isomer is a particularly important manufacturing impurity because positional isomerism can affect crystallization, melting behavior, polymer regularity, and reaction performance.
Synonyms and Common Names: Bisphenol S, BPS, 4,4'-Sulfonyldiphenol, 4,4'-Sulphonyldiphenol, 4,4'-Dihydroxydiphenyl Sulfone, 4,4'-Dihydroxydiphenyl Sulphone, Bis(4-hydroxyphenyl) Sulfone, Bis(4-hydroxyphenyl) Sulphone, Bis(p-hydroxyphenyl) Sulfone, p,p'-Dihydroxydiphenyl Sulfone, 4,4'-Sulfonylbisphenol, Sulfonylbisphenol, 1,1'-Sulfonylbis(4-hydroxybenzene), 1,1'-Sulfonylbis[4-hydroxybenzene], 4-(4-Hydroxyphenylsulfonyl)phenol, 4-(4-Hydroxybenzenesulfonyl)phenol, Phenol, 4,4'-sulfonyldi-, 4,4'-Bisphenol S, Dihydroxydiphenyl Sulfone, DHDPS, SDP
TECHNICAL IDENTIFICATION
Chemical Name: Phenol, 4,4'-sulfonylbis-
Common Chemical Name: Bisphenol S
Chemical Family: Bisphenols and aromatic sulfones
IUPAC Name: 4-(4-Hydroxyphenylsulfonyl)phenol
CAS Number: 80-09-1
EC Number: 201-250-5
Molecular Formula: C12H10O4S
Molecular Weight: 250.27 g/mol
InChIKey: VPWNQTHUCYMVMZ-UHFFFAOYSA-N
Functional Groups: Two phenolic hydroxyl groups and one sulfone bridge
PHYSICAL AND CHEMICAL PROPERTIES
Appearance: White to off-white crystalline powder
Physical State: Solid
Odor: Odorless or faint characteristic odor
Melting Point: Approximately 240–250 °C, depending on purity and analytical method
Thermal Decomposition: Approximately 330 °C
Boiling Point: Not directly measurable because decomposition occurs before normal boiling
Density: Approximately 1.366 g/cm3 at 15 °C
Water Solubility: Approximately 770 mg/L at 20 °C
Organic Solubility: Soluble in selected polar organic solvents and increasingly soluble in alkaline media through phenolate formation
Vapor Pressure: Calculated at approximately 6.3 × 10^-8 Pa at 25 °C
Log Kow: Approximately 2.36 at 24.5 °C
Dissociation Constant: pKa approximately 7.02 at 25 °C
Volatility from Water: Very low
Flash Point: No dependable standard value established
Combustible Dust Potential: Fine airborne powder may form combustible dust concentrations
Hydrolytic Stability: Resistant to hydrolysis under ordinary environmental pH conditions
Biodegradability: Not readily biodegradable
Bioaccumulation Potential: Low based on measured bioconcentration behavior
Storage Stability: Stable under appropriate dry, cool, and uncontaminated conditions
Water solubility and distribution behavior depend on pH because the phenolic groups can dissociate.
Neutral molecules dominate under acidic conditions, while phenolate forms become increasingly important as the pH approaches and exceeds the dissociation constant.
Published values describe representative substance properties rather than guaranteed commercial limits.
Lot acceptance should be based on the agreed specification and Certificate of Analysis.
FUNCTIONAL CHARACTERISTICS
Phenol, 4,4'-sulfonylbis- provides two para-oriented hydroxyl groups capable of forming ethers, esters, carbonates, glycidyl derivatives, and other functional products.
This bifunctionality makes the material suitable for step-growth polymerization and preparation of high-performance resin intermediates.
The sulfone bridge is strongly polar and electron withdrawing.
This structure contributes to molecular rigidity, high melting temperature, thermal resistance, oxidative stability, and stronger phenolic acidity than many other common bisphenols.
In polymer synthesis, purity and stoichiometric balance directly influence molecular weight.
Monofunctional impurities, positional isomers, moisture, residual phenol, and inorganic residues can terminate chains, disturb regularity, increase color, or alter melt performance.
In thermal-paper systems, the phenolic groups function as proton donors to compatible leuco dyes when the coating is heated.
Developer melting behavior, particle size, dispersion, compatibility with sensitizers, and background stability determine image density and print durability.
Phenol, 4,4'-sulfonylbis- should not be described automatically as a safer replacement for Bisphenol A.
The material has its own reproductive and endocrine-related hazard profile and requires independent regulatory assessment.
PRODUCTION AND COMMERCIAL FORM
Phenol, 4,4'-sulfonylbis- is commonly manufactured through dehydration and condensation of phenol with sulfuric acid, sulfur trioxide, or an equivalent sulfonating system.
Reaction conditions must be controlled to promote formation of the desired 4,4'-isomer while limiting the 2,4'-isomer and colored secondary products.
An alternative route involves oxidation of 4,4'-thiodiphenol to the corresponding sulfone.
The relevance of thiodiphenol and partially oxidized sulfur compounds as impurities depends on the selected manufacturing route.
Crude material can be purified through neutralization, phase separation, filtration, crystallization, recrystallization, washing, and controlled drying.
High-purity grades may require additional purification to reduce positional isomers, residual phenol, inorganic salts, metals, and colored compounds.
Phenol, 4,4'-sulfonylbis- is normally supplied as crystalline powder.
Particle size, bulk density, flowability, caking tendency, dust level, and solution color can be adjusted or controlled for particular processing requirements.
Commercial categories may include technical grade, thermal-paper grade, high-purity polymer grade, reagent grade, and analytical-reference grade.
These descriptions are not universal specifications and must be supported by defined analytical limits.
APPLICATIONS AND INDUSTRIES
Polyethersulfone and High-Performance Polymers
Phenol, 4,4'-sulfonylbis- serves as a major bisphenolic monomer for polyethersulfone and related polyarylene ether sulfone materials.
Alkaline activation of the phenolic groups enables polycondensation with compatible difunctional aromatic halides.
The rigid aromatic structure and sulfone linkage support polymers with elevated glass-transition temperature, dimensional stability, chemical resistance, and useful mechanical properties.
Final polymer performance also depends on the comonomer, molecular weight, end-group control, processing history, and residual-solvent level.
Polymerization-grade material requires precise control of chemical purity, hydroxyl functionality, isomer content, moisture, metals, ionic residues, and color.
Small stoichiometric deviations can substantially reduce achievable molecular weight in step-growth polymerization.
Epoxy Resins, Adhesives, and Coatings
Phenol, 4,4'-sulfonylbis- functions as a precursor to sulfone-containing epoxy monomers and thermosetting resin components.
Conversion of the hydroxyl groups into glycidyl functionality provides epoxy intermediates designed for applications requiring increased rigidity and thermal performance.
Phenol, 4,4'-sulfonylbis- also finds use in selected fast-curing adhesive, protective-coating, and corrosion-control systems.
The exact role may involve reactive incorporation, curing modification, adhesion development, or preparation of a downstream resin rather than direct addition of the unmodified material.
Curing temperature, catalyst selection, hydroxyl equivalent, epoxy equivalent, viscosity, and residual monomer must be optimized for the intended system.
A direct substitution for another bisphenol can change cure kinetics, crosslink density, brittleness, color, and solvent resistance.
Thermal Paper
Phenol, 4,4'-sulfonylbis- functions as a color developer in selected thermal papers used for receipts, tickets, labels, and recording media.
Heat from the print head causes interaction between the developer and a leuco dye, producing the visible image.
Developer performance depends on acidity, melting behavior, particle-size distribution, dispersion quality, coating uniformity, sensitizer compatibility, and binder selection.
The formulation must balance rapid image formation against background discoloration, humidity resistance, light stability, and long-term image retention.
Thermal-paper use is subject to increasing regulatory and customer scrutiny because handling can create dermal exposure and recycling can transfer residual developer into other paper streams.
Buyers should confirm market-specific restrictions and downstream declarations before selecting this application.
Dyes, Textiles, and Leather
Phenol, 4,4'-sulfonylbis- is used in selected dye-fixation, dyeing-aid, textile-treatment, and leather-processing chemistries.
The aromatic hydroxyl groups and sulfone functionality can support interactions with dyes, fibers, resins, and reactive intermediates.
Performance must be evaluated for shade, wash fastness, light fastness, fiber strength, residual monomer, wastewater behavior, and compatibility with other treatment agents.
Regulatory restrictions may make substitution or closed-system processing necessary in consumer textile applications.
Flame-Resistant and Heat-Resistant Materials
Phenol, 4,4'-sulfonylbis- serves as a raw material for certain thermally resistant polymers, resin modifiers, and flame-retardant derivatives.
The aromatic sulfone structure can contribute to thermal stability, but the presence of sulfur does not by itself guarantee a specific flame-retardancy classification.
Flame performance must be demonstrated in the complete finished formulation.
Polymer structure, loading, fillers, synergists, thickness, processing, and test method all influence the result.
Photographic and Imaging Chemistry
Phenol, 4,4'-sulfonylbis- has specialized use as an intermediate for photographic couplers and imaging-related chemicals.
These applications generally require close control of color, isomeric purity, metals, insoluble matter, and reactive impurities.
Specialty Chemical Intermediates
Phenol, 4,4'-sulfonylbis- provides a platform for preparing ethers, esters, glycidyl derivatives, brominated compounds, sulfonates, and functional aromatic monomers.
Phenol, 4,4'-sulfonylbis- can also support research into membranes, ion-exchange materials, high-temperature resins, and specialty coatings.
Analytical and Environmental Testing
Phenol, 4,4'-sulfonylbis- is used as an analytical reference substance for detecting Bisphenol S in thermal paper, polymers, coatings, food-contact materials, water, sediment, biological matrices, and recycled paper.
Testing commonly relies on high-performance liquid chromatography or liquid chromatography coupled with mass spectrometry.
Reference-standard applications require assigned purity or concentration, measurement uncertainty, traceability, stability information, and suitable packaging.
An ordinary technical-grade product should not be treated as a certified analytical standard.
Food-Contact Materials
Phenol, 4,4'-sulfonylbis- has historically been associated with certain plastics, resin coatings, and can-lining applications.
Current regulatory assessments no longer support treating the substance as an unrestricted Bisphenol A replacement.
Within the European Union, hazardous bisphenols such as Phenol, 4,4'-sulfonylbis- are prohibited in food-contact materials unless a specific authorization or applicable transitional provision permits the intended application.
Food-contact suitability must be established for the precise material, manufacturing date, market, migration conditions, and legal pathway.
GRADE SELECTION AND PRODUCT SUITABILITY
Technical grade may be appropriate for downstream synthesis when the process includes additional purification and can tolerate defined isomeric or inorganic impurities.
Minimum assay, melting range, moisture, color, ash, residual phenol, and 2,4'-isomer content should still be agreed before purchase.
Thermal-paper grade requires controlled melting behavior, fine particle size, dispersion performance, image-development response, and background stability.
Chemical assay alone cannot predict coating performance.
High-purity polymer grade requires stringent control of 4,4'-isomer content, phenolic functionality, water, metals, ionic residues, residual phenol, color bodies, and monofunctional impurities.
Solution color and polymerization trials may be more informative than appearance of the dry powder.
Reagent grade is suitable for general laboratory synthesis when a defined assay and impurity profile meet the experimental requirement.
Analytical-reference grade requires additional characterization, traceability, uncertainty, and stability documentation.
Food-contact, medical, pharmaceutical, cosmetic, or sensitive consumer applications require separate legal and toxicological evaluation.
A nominal purity of 99% or higher does not establish suitability for a regulated end use.
FORMULATION AND PROCESS CONSIDERATIONS
Phenol, 4,4'-sulfonylbis- has limited water solubility under neutral conditions but becomes more soluble when converted to phenolate salts in alkaline media.
Aqueous processing must account for pH-dependent solubility, precipitation during neutralization, and possible carryover into wastewater.
Dissolution in organic media depends on solvent polarity, temperature, water content, and concentration.
Laboratory solubility and cooling tests should be completed before scale-up to prevent uncontrolled crystallization, filter blockage, or transfer-line deposits.
Polyethersulfone production commonly requires controlled formation of an alkali phenolate followed by reaction with an activated aromatic dihalide in a suitable high-boiling solvent.
Moisture removal, monomer stoichiometry, mixing, temperature profile, oxygen control, and end-group management are critical to molecular-weight development.
Residual water can consume reactive species or disturb polymerization conditions.
Polymer-grade material should therefore be stored and conditioned according to the moisture limit agreed for the process.
Thermal-paper coating requires uniform dispersion of the developer with the selected leuco dye, sensitizer, binder, lubricant, and stabilizing components.
Grinding conditions must prevent excessive heat, contamination, agglomeration, and uncontrolled changes in crystal form.
Premature interaction between the developer and dye can increase background color before printing.
Particle size, coating pH, drying temperature, storage humidity, and contact with alkaline contaminants should be controlled.
Epoxy and coating applications require adjustment of cure stoichiometry, catalyst level, solvent package, and processing temperature.
The sulfone bridge can increase rigidity and heat resistance while also increasing melting temperature and potentially reducing room-temperature processability.
Fine powder can become airborne during bag opening, charging, milling, and blending.
Enclosed transfer, local exhaust ventilation, grounded equipment, and controlled addition reduce exposure and combustible-dust risk.
QUALITY, SPECIFICATIONS AND DOCUMENTATION
A purchasing specification should identify the intended grade, minimum assay, analytical method, purity basis, melting range, moisture, physical form, and packaging requirement.
Application-specific limits may also include hydroxyl value, solution color, ash, metals, particle size, bulk density, and insoluble matter.
Critical organic impurities can include 2,4'-sulfonyldiphenol, residual phenol, diphenyl sulfone, thiodiphenol, partially oxidized sulfur compounds, and other condensation products.
Inorganic impurities can include sulfate, residual acid, alkali salts, catalyst residues, iron, and ash-forming material.
Chromatographic analysis is useful for assay and positional-isomer control.
Melting-range analysis, moisture determination, elemental testing, ash measurement, color evaluation, and spectroscopic identity testing provide complementary quality information.
Polymer-grade evaluation may include phenolic hydroxyl content, monofunctional impurity limits, solution transmittance, polymerization performance, and resulting resin color.
Thermal-paper evaluation may include particle-size distribution, melting profile, image density, sensitivity, background color, and accelerated ageing.
A Certificate of Analysis should report actual lot results for parameters that determine customer performance.
A Technical Data Sheet provides representative information, while a Safety Data Sheet communicates classification, exposure controls, storage, disposal, and emergency requirements.
Buyers should define requirements for regulatory declarations, substance-of-very-high-concern status, residual-monomer information, change notification, batch traceability, shelf life or retest period, and country-of-origin documentation.
Documentation should be reviewed before purchase when the material will enter polymers, articles, coatings, paper, or other regulated supply chains.
SAFETY AND REGULATORY CONSIDERATIONS
Phenol, 4,4'-sulfonylbis- has a harmonized European classification as reproductive toxicant Category 1B.
The corresponding hazard statement indicates that Phenol, 4,4'-sulfonylbis- may damage fertility and may damage the unborn child.
Within the European REACH framework, Phenol, 4,4'-sulfonylbis- is included on the Candidate List of substances of very high concern.
The listing is based on reproductive toxicity and endocrine-disrupting properties affecting human health and the environment.
California Proposition 65 lists Bisphenol S for female reproductive toxicity, male reproductive toxicity, and developmental toxicity.
Businesses supplying affected markets should evaluate exposure, warning, reformulation, and documentation obligations.
Workers who are pregnant, planning pregnancy, or otherwise potentially exposed to reproductive hazards require protection within a comprehensive occupational-risk program.
Exposure should be minimized for all personnel rather than managed only for selected worker groups.
Dust may be inhaled or transferred to the skin during open handling.
Although acute irritation may be limited in some test systems, this does not reduce the importance of reproductive and endocrine-related hazards.
Phenol, 4,4'-sulfonylbis- is not readily biodegradable and may persist in wastewater, paper-recycling streams, and environmental compartments.
Measured bioconcentration potential is low, but environmental release remains undesirable because endocrine-related effects can occur independently of high bioaccumulation.
Fine powder may form combustible dust concentrations in air.
Ignition sources, static discharge, dust layers, hot surfaces, and uncontrolled powder dispersion should be addressed through a site-specific dust-hazard assessment.
Thermal decomposition or combustion can release carbon oxides, sulfur oxides, phenolic vapors, and other irritating or toxic fumes.
Firefighters require appropriate respiratory protection and control of contaminated runoff.
The pure material is generally not classified as dangerous goods under the principal road, sea, and air transport systems.
The final transport status must nevertheless be confirmed from the current product-specific Safety Data Sheet because formulation, jurisdiction, and package contents can change the classification.
FIRST AID
Inhalation: Move the exposed person to fresh air, keep them at rest, and obtain medical advice if coughing, irritation, dizziness, breathing difficulty, or other symptoms occur.
Skin Contact: Remove contaminated clothing and wash the affected skin thoroughly with soap and water.
Eye Contact: Rinse cautiously with clean water for at least 15 minutes, remove contact lenses when easy, continue rinsing, and obtain medical attention if irritation persists.
Ingestion: Rinse the mouth, do not induce vomiting unless directed by medical personnel, and obtain medical advice.
Note to Medical Personnel: Treat symptomatically and provide the product-specific Safety Data Sheet together with available information on exposure route, duration, and quantity.
HANDLING AND STORAGE
Handling: Use closed transfer where practical, avoid generating dust, and prevent contact with the skin, eyes, and clothing.
Ventilation: Provide local exhaust at bag opening, charging, sampling, milling, blending, and packaging points.
Personal Protection: Use suitable protective gloves, eye protection, protective clothing, and respiratory protection selected through an exposure assessment.
Hygiene: Wash thoroughly after handling and prohibit eating, drinking, and smoking in processing areas.
Storage: Keep tightly closed in a cool, dry, well-ventilated area protected from heat, sunlight, contamination, and moisture.
Incompatibilities: Separate from strong oxidizing agents and other materials identified as incompatible by the current Safety Data Sheet.
Fire Prevention: Control airborne dust, accumulated deposits, static electricity, sparks, flames, and hot surfaces.
Spill Control: Avoid raising dust, collect the material with suitable filtered equipment, and place it in a labelled compatible container.
Waste Management: Prevent release to drains and dispose of product, contaminated dust, and packaging through an authorized chemical-waste route.
PACKAGING AND PROCUREMENT CONSIDERATIONS
Phenol, 4,4'-sulfonylbis- may be packaged in moisture-resistant bags with compatible liners, lined fibre drums, plastic drums, or other clean industrial containers.
The packaging should protect the material from humidity, contamination, discoloration, and physical damage.
High-purity polymer grade benefits from low-contamination packaging, secure liners, controlled headspace, and documented package-contact materials.
Analytical-reference material may require sealed glass containers, light protection, smaller unit sizes, and defined storage temperatures.
Powder packaging should support controlled discharge without excessive dust formation.
Bag dimensions, liner strength, pallet stability, antistatic precautions, and compatibility with automated charging systems should be reviewed before bulk procurement.
Procurement documents should specify grade, assay, isomer limits, moisture, color, particle size, package type, net quantity, pallet configuration, shelf life, storage conditions, and required regulatory documents.
For sensitive applications, a representative sample and polymerization, coating, or analytical trial should be completed before approval of routine supply.
Ataman Kimya can support buyers in selecting Phenol, 4,4'-sulfonylbis- according to purity, isomer profile, polymerization performance, thermal-paper requirements, documentation, packaging, regulatory status, and intended industrial application.
To discuss a product-specific enquiry, contact Ataman Kimya at +90 216 577 10 10 or info@atamankimya.com.
