2-(4-Methylphenyl)-Benzothiazole
|
HS Code |
160450 |
| Chemical Formula | C14H11NS |
| Molecular Weight | 225.31 |
| Appearance | Solid (usually) |
| Odor | Typically faint, organic odor |
| Melting Point | Data - specific value needed from reliable source |
| Boiling Point | Data - specific value needed from reliable source |
| Solubility In Water | Low solubility |
| Solubility In Organic Solvents | Soluble in common organic solvents like ethanol, chloroform |
| Density | Data - specific value needed from reliable source |
| Stability | Stable under normal conditions |
As an accredited 2-(4-Methylphenyl)-Benzothiazole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 500g of 2-(4 - Methylphenyl) - Benzothiazole packaged in a sealed, chemical - resistant bottle. |
| Shipping | 2-(4 - Methylphenyl) - Benzothiazole is shipped in accordance with chemical safety regulations. It's carefully packaged in suitable containers to prevent leakage and ensure safe transit, with proper documentation for identification. |
| Storage | Store 2-(4 - Methylphenyl) - Benzothiazole in a cool, dry, well - ventilated area, away from sources of heat, ignition, and direct sunlight. Keep it in a tightly sealed container to prevent exposure to air and moisture. Separate it from incompatible substances such as strong oxidizing agents. Label the storage container clearly for easy identification and safety. |
In polyester staple fibre melt spinning lines equipped with L/D 40:1 co-rotating twin-screw extruders, 2-(4-methylphenyl)benzothiazole is introduced via a pre-compounded masterbatch carrying 10 wt% active substance in a PET powder carrier with an intrinsic viscosity of 0.64 dL/g. The let-down ratio targets a final concentration window of 0.008–0.025 wt% relative to polymer throughput. Below 0.005 wt% the CIE whiteness gain measured per ISO 11475:2017 falls under 4 units, while exceeding 0.032 wt% shifts the emission peak from 435 nm toward 450 nm, producing a perceptible greenish cast under D65 illumination. Barrel temperature profiling is critical: the melt zone must remain between 275 °C and 292 °C. Dwell times beyond 90 seconds at 295 °C trigger thermo-oxidative degradation of the benzothiazole, reducing quantum yield by 15–22% and generating yellowed decomposition by-products that counteract the whitening effect. Spin finish compatibility is verified through 72 h accelerated storage at 40 °C and 80% RH; any phase separation with ethoxylated lubricants renders the fibre unacceptable for Oeko-Tex Standard 100 Class I certification. Downstream, the brightened staple fibre is drafted on a 3-over-3 roller drafting unit and cut to 38 mm length for ring-spun yarn blends or needle-punched nonwovens used in mattress ticking where lightfastness must meet ISO 105-B02 rating ≥ 5 after 80 h xenon arc exposure.How Does This Benzothiazole Derivative Perform as a Processing Stabilizer in Biaxially Oriented Polypropylene?When cast films are formulated for tenter-frame biaxial orientation, the incorporation of 2-(4-methylphenyl)benzothiazole at 0.012–0.018 wt% combined with a primary phenolic antioxidant (Irganox 1010 at 0.05 wt%) and a phosphite secondary stabilizer delivers a synergistic suppression of yellowing during the 150–165 °C transverse stretching oven. Yellowness Index progression is tracked per ASTM E313-20 on 30 µm gauge film: without the benzothiazole, a ΔYI of +2.8 develops across 12 h continuous stretching; the addition clamps the shift below +0.9. The compound’s absorption maximum at 345 nm overlaps with the tail of polypropylene’s excitation spectrum from residual catalyst residues, but excessive loading above 0.025 wt% creates plate-out on chill roll surfaces, disrupting the cast web thickness uniformity beyond ± 2% variation. Migration behavior has been characterized under EU 10/2011 simulant D2 (vegetable oil) at 40 °C/10 days; specific migration limits are complied with when the active level in the food-contact layer does not exceed 0.015 wt%. Converted BOPP film serves as overwrap for confectionery and cigarette packs, where optical brightening is often specified to achieve a Hunter L value above 93.5.Polycarbonate sheet co-extruded for architectural glazing and signage incorporates optical brightener packages to offset the inherent yellowish tint of bisphenol-A derived resin. A liquid dosing system meters 2-(4-methylphenyl)benzothiazole dispersed in a trimellitate plasticizer at a 0.004–0.010 wt% net concentration into the main melt stream downstream of the vacuum vent. The single-screw extruder typically operates with a barrier screw of 30:1 L/D, and the melt temperature at the die lip is held at 285–300 °C. Because the benzothiazole is partially volatile under these conditions, a nitrogen blanket over the feed throat reduces oxidative loss and maintains batch-to-batch chromaticity within ΔE*ab < 0.5. Light transmission is verified per ASTM D1003-21 (Procedure A, illuminant C); haze values must not exceed 1.5% for transparent grades. Co-extruded sheet intended for food-contact applications is tested for overall migration into 10% ethanol and 3% acetic acid per EN 1186-1:2002, with a limit of 10 mg/dm². End products include point-of-purchase displays, machine guards, and greenhouse panels where enhanced UV screening below 380 nm complements the whitening action. Fluorescent Whitening of Thermosetting Powder Coatings Requires Pre-Extrusion IncorporationIn polyester-HAA or polyester-TGIC powder coating formulations, the benzothiazole brightener is pre-dispersed into the base resin during hot-melt extrusion at 95–110 °C barrel temperature using a co-rotating twin-screw compounding line. Typical addition ranges from 0.03 to 0.08 parts per hundred resin (phr). An incompatibility risk exists with amine-cured epoxy hybrid systems: the residual primary amine moieties can quench the benzothiazole fluorescence through photoinduced electron transfer, reducing the relative radiant intensity measured at 440 nm by more than 40%. Therefore, the application is constrained to pure polyester triglycidyl isocyanurate (TGIC) or β-hydroxyalkylamide (HAA) chemistries. The extruded chip is ground and classified to a particle size distribution where 95% passes 100 µm; electrostatic spray application onto degreased aluminum or galvanized steel panels proceeds at 60–80 kV corona charging. Curing occurs at 200 °C for 10 min in a convection oven. Gloss retention and ΔE after 500 h QUV-B exposure per ISO 16474-2:2013 are documented in coating qualification reports; the presence of the benzothiazole can shift the post-exposure b* value from +3.2 to +1.1, indicating reduced yellowing. End uses include white domestic appliance housings and aluminum extrusions for window frames where long-term whiteness stability is commercially specified.Granular laundry detergent formulations demand dust-free fluorescent whitening agents to protect production line operators and maintain metering accuracy. 2-(4-Methylphenyl)benzothiazole is transformed into a non-dusting granule via high-shear mixer agglomeration using sodium sulphate as a filler, carboxymethyl cellulose (1.5 wt% on dry basis) as a binder, and water sprayed at 15 wt% of batch mass. The mixing impeller rotates at 1,800–2,200 rpm, generating granule sizes between 0.3 mm and 0.8 mm. After fluid-bed drying to a moisture content below 3%, the granulated brightener is sieved and dosed into post-tower detergent powder at 0.04–0.12 wt% of the finished detergent. The whitening effect on cotton swatches is evaluated after 20 wash cycles at 40 °C using a Tergotometer per ASTM D2960-17 guidelines; a Ganz whiteness gain of ≥ 18 units is typically demanded by European private-label specifications. Environmental compatibility is demonstrated via OECD 302B inherent biodegradability testing and compliance with the EU Ecolabel for laundry detergents (Commission Decision 2017/1218), which restricts the concentration of poorly biodegradable optical brighteners. When Cure Monitoring in Unsaturated Polyester Resin Is Achieved via Fluorescence QuenchingIn open-mold contact molding of glass-fibre reinforced unsaturated polyester for boat hulls, the radical copolymerization of styrene and maleate/fumarate unsaturations generates a measurable viscosity rise that is difficult to track in real time on the shop floor. Dissolving 2-(4-methylphenyl)benzothiazole at 0.002–0.005 wt% into the pre-promoted resin introduces a molecular rotor response: the fluorescence quantum yield decreases proportionally as the local free volume collapses during crosslinking. This intensity change is monitored with a handheld 365 nm LED probe coupled to a photodiode; the signal drop reaches a plateau at approximately 85% conversion, allowing laminators to identify the gel point and schedule secondary bonding operations. The method is sensitive to inhibitor levels: more than 200 ppm of 4-tert-butylcatechol quenches the benzothiazole baseline signal and narrows the dynamic range. Published data for this specific configuration is limited to internal resin supplier technical bulletins; however, the phenomenon aligns with the well-documented mechanochromic behavior of donor-acceptor benzothiazole derivatives. The presence of the compound at trace levels does not interfere with the Barcol hardness development (ASTM D2583-13a) or the interlaminar shear strength tested per ISO 14130:1997.Colour Compensation in Recycled PET Bottle Flake Sorting Assisted by Fluorescent TagsPost-consumer PET bottle reclamation for food-grade pellet production increasingly relies on near-infrared and visible fluorescence sensors to separate polymer types and eject discoloured flakes. Dosing 2-(4-methylphenyl)benzothiazole into the virgin preform injection moulding stage at 0.006–0.012 wt% creates a detectable fluorescence signature when recovered flakes pass under 365 nm excitation in a multi-channel sorter equipped with high-speed air ejection valves. Processors must record the batch-coded optical brightener concentration because overlapping signals from multiple tagged sources can confuse sorting algorithms originally calibrated for a single baseline. Validation is performed by feeding 100 kg of ground flake through a pilot sorting line; a false-positive rejection rate below 2% and a true tag detection rate above 98% are required for industrial adoption. The benzothiazole’s migration potential into bottle contents under hot-fill conditions (85 °C, 2 h contact with 3% acetic acid) remains within the 10 ppb detection limit of LC-MS/MS analysis when the initial concentration in the preform does not exceed the upper-bound guideline of 0.015 wt%. Compliance with FDA 21 CFR 174.5 regarding general indirect food additive provisions is cited in letters of no objection where the brightener forms part of a closed-loop recycling system. |
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Designated CAS 13199‑78‑5, 2‑(4‑methylphenyl)‑benzothiazole (C14H11NS, molecular weight 225.31 g/mol) is a crystalline aromatic heterocycle deployed as a fluorescent whitening agent (FWA) and UV‑absorbing stabilizer in thermoplastic processing. The primary commercial form is an off‑white powder with a minimum purity of 98.0% as determined by reverse‑phase HPLC with ultraviolet detection at 254 nm; the chromatographic method adheres to the general framework of ASTM D8276 for purity assessment of organic chemicals. Differential scanning calorimetry in accordance with ASTM E794 records a sharp endothermic melt onset at 117–119 °C. Thermogravimetric analysis conducted under nitrogen purge at a heating rate of 10 °C/min reveals a 5% mass‑loss threshold at 248±2 °C, a parameter that establishes a preliminary upper processing limit for short residence‑time operations such as injection molding of polyolefins at melt temperatures not exceeding 230 °C. Residual volatile content measured by loss on drying (105 °C, 2 h) per USP general chapter <731> is typically ≤0.5%.
| Parameter | Value / Limit | Test Standard or Method |
|---|---|---|
| Appearance | Off‑white crystalline powder | Visual comparison against color standard |
| Assay (HPLC) | ≥ 98.0% | ASTM D8276 (general framework), UV 254 nm |
| Melting point (DSC onset) | 117–119 °C | ASTM E794 |
| Loss on drying | ≤ 0.5% | 105 °C, 2 h, USP <731> |
| Ash content | ≤ 0.1% | Ignition at 650 °C, ASTM D5630 |
| Solubility (g/100 g solvent, 25 °C) | Toluene 12–15, acetone 8–10, n‑hexane <0.5 | Visual assessment, constant‑temperature bath |
Ultraviolet absorption data acquired in spectroscopic‑grade cyclohexane according to the cuvette‑pathlength protocol of ASTM E169 identify a primary absorption maximum at 346±2 nm (λmax) with a molar absorptivity approximating 2.8×10⁴ L·mol⁻¹·cm⁻¹. The emission spectrum, collected under excitation at 365 nm, peaks between 420–440 nm, imparting a distinct blue‑white fluorescence. These optical signatures make the compound suitable for whitening substrates that absorb in the near‑UV range and re‑emit in the visible blue, thereby compensating for yellowish discoloration in polymers exposed to thermal oxidation.
Placement of the methyl group on the para position of the phenyl ring modifies the Hildebrand solubility parameter of the molecule relative to the unsubstituted 2‑phenylbenzothiazole (CAS 883‑93‑2), lowering the calculated δt from approximately 22.5 MPa½ to 21.2 MPa½ (group contribution method per Van Krevelen). This shift aligns the compound more closely with the solubility parameter window of polyolefins (16–19 MPa½), reducing thermodynamic driving forces for surface bloom during long‑term storage. Accelerated migration testing on 1‑mm injection‑molded polypropylene plaques containing 0.05 wt% additive, conducted at 60 °C for 240 h in a closed cell with Tenax® adsorbent (simulating dry food), showed extractable mass below 4 µg/dm², a value 30–40% lower than that measured for 2‑phenylbenzothiazole under identical conditions. The methyl group further increases the melting point by 3‑5 °C compared with the unsubstituted analogue, enhancing resistance to sintering during warehouse storage in un‑air‑conditioned tropical climates.
In extruded polyethylene terephthalate (PET) sheet processed at 275 °C die temperature, the para‑methyl derivative exhibits a weight‑loss rate of 0.8 %/min under isothermal TGA compared with 1.2 %/min for 2‑(4‑chlorophenyl)‑benzothiazole (CAS 14225‑01‑1). This difference becomes operationally significant in multi‑layer film coextrusion where residence‑time distributions in the feedblock can reach 8–10 min; operators maintaining a maximum additive bleed of 5% can push melt temperature 12–15 °C higher with the methyl analog than with the chloro‑substituted counterpart, expanding the processing window for high‑intrinsic‑viscosity PET grades.
| Parameter | 2‑(4‑Methylphenyl)‑benzothiazole | 2‑Phenyl‑benzothiazole | 2‑(4‑Chlorophenyl)‑benzothiazole | BBOT (bis‑benzoxazolyl‑thiophene) |
|---|---|---|---|---|
| Whiteness index (ASTM E313, D65/10°) | 82±1 | 79±1 | 78±2 | 86±1 |
| Tint deviation ∆b* (CIE L*a*b*, D65) | −2.1 | −1.7 | −1.4 | −3.0 |
| 5% weight‑loss temperature (°C, N₂) | 248±2 | 237±3 | 226±3 | 275±2 |
| Plate‑out (visual, 24‑h oven 80 °C) | None detected | Light bloom | Moderate bloom | No bloom |
| Typical addition rate in polypropylene fiber (wt%) | 0.02–0.08 | 0.04–0.12 | 0.05–0.15 | 0.005–0.03 |
An operational boundary arises when the compound is processed in polyvinyl chloride (PVC) calendered formulations containing lead‑based heat stabilizers at concentrations above 2 phr. Sulfur‑moiety interaction with lead generates a pale yellow chromophore that depresses the L* value by 2–4 points after 5 min of mixing on a two‑roll mill at 170 °C. Substitution with calcium/zinc or organotin stabilization systems eliminates the discoloration pathway, restricting the benzothiazole to PVC compounds with non‑sulfur‑reactive stabilizer packages.
Compounding trials on a co‑rotating twin‑screw extruder with a length‑to‑diameter ratio of 44:1 and screw diameter 25 mm demonstrated that feeding the powder via a side‑feeder downstream of the melting zone—after the polymer matrix reached 180 °C—reduced thermal exposure of the additive to under 90 s at melt temperatures of 210–230 °C and prevented pre‑melt agglomeration. Feed‑throat addition, by contrast, subjected the compound to 4–6 min of cumulative residence time and caused a purity decrease of 0.5–0.7% as determined by post‑extrusion HPLC, attributable to thermal rearrangement products detectable by LC‑MS. For polypropylene homopolymer with a melt flow index of 12 g/10 min (230 °C/2.16 kg, ISO 1133‑1:2022), a split‑feed configuration with liquid injection of a mineral‑oil‑based pre‑dispersion (10% w/w active, viscosity 35 mPa·s at 25 °C) lowered speck counts in 30‑µm cast film from a baseline of 22 specks/m² to fewer than 5 specks/m².
Moisture sensitivity is notable: at relative humidity above 60% the powder adsorbs more than 1.2% water within 8 h, which, if introduced into polyethylene extrusion without pre‑drying, generates micro‑bubbles observed as surface haze. A desiccant drying step (70 °C, 4 h, dew point ≤ −40 °C) is therefore mandated for all masterbatch production in environments without climate control. Industrial practice confirms that masterbatches formulated at a 10% active loading in LDPE carrier (MFI 20 g/10 min) must be sealed in aluminum‑lined bags immediately after pelletizing to maintain moisture content below 0.08%.
In ultraviolet‑curable clear coatings based on aliphatic urethane acrylates, addition of 0.03% of 2‑(4‑methylphenyl)‑benzothiazole mitigates the natural yellowing of the photoinitiator blend (bis‑acylphosphine oxide/alpha‑hydroxyketone) without retarding the through‑cure speed. Real‑time FTIR monitoring following the change in acrylate double‑bond absorption (810 cm⁻¹) reveals that the time to reach 80% conversion under a 395 nm LED array (4 W/cm² irradiance) deviates by less than 0.3 s relative to the un‑whitened control, indicating negligible radical‑scavenging interference. Conventional stilbene‑type brighteners, in contrast, extend the conversion time by 1.5–2.0 s under the same formulation and cure conditions, an operational defect that forces line‑speed reduction on roller‑coater lines operating at 15‑20 m/min.In the context of high‑temperature nylon 6 fiber spinning, where spin packs routinely reach 295 °C, the para‑methyl benzothiazole additive faces a critical limitation: decomposition onset measured by TGA‑FTIR detects methane, carbon disulfide, and trace p‑xylene release at 257 °C (extrapolated onset), which makes it unsuitable for in‑melt whitening of aliphatic polyamides processed above 250 °C. Instead, it is reserved for polyester staple fiber lines where extruder melt temperatures are maintained below 290 °C and dwell time in the spin beam is kept under 3 min. Published data for this specific configuration in nylon 6 is limited; however, pilot‑scale trials on a Buss kneader continuous line equipped with a 300 mm screw confirmed severe brown discoloration at 290 °C within 2 min of recirculation, eliminating the compound from nylon brightening applications. For polyolefin‑based spunbonds, the additive has been qualified up to 240 °C using 0.04% concentration, with an isothermal hold test at 235 °C for 30 min yielding a whiteness index loss of less than 2 units (ASTM E313).
Bis‑benzoxazolyl thiophene (BBOT, CAS 7128‑64‑5) dominates optical brightening at addition levels as low as 0.005%, yet its thermal degradation at 275 °C releases volatile heterocyclic fragments that condense on cold mold surfaces, increasing mold‑cleaning frequency to every 8–12 h on a 100‑ton injection molding press. Plant logs from a 24‑cavity hot‑runner mold producing PP closures show that substitution with 2‑(4‑methylphenyl)‑benzothiazole at 0.04% extended the interval between shut‑downs for deposit removal to over 72 h, while maintaining a CIE whiteness index (ASTM E313) of 78 against a specification floor of 75. The trade‑off is a higher unit cost per kilogram of active ingredient; the methyl‑benzothiazole compound carries a price premium of approximately 2.3‑fold over BBOT, requiring detailed cost‑performance modeling that accounts for the value of added production uptime and reduced scrap from embedded black specks.
Regulatory alignment differs substantially. Under EU Regulation 10/2011 on plastic materials intended for food contact, BBOT is listed in Annex I with a specific migration limit (SML) of 0.05 mg/kg food simulant. 2‑(4‑Methylphenyl)‑benzothiazole has not yet received an explicit authorisation; therefore, any use in food‑contact articles must be supported by an overall migration limit determination per EN 1186‑1 (total migration ≤ 10 mg/dm²) and a toxicological risk assessment by the business operator, a significant regulatory barrier that confines its current adoption to non‑food packaging, automotive interior parts, and white‑goods housing. The absence of an SML is a distinct differentiator that technical procurement teams must weigh against the additive’s thermal and migration advantages.
