2-Thienyl Thiazole
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HS Code |
958562 |
| Chemical Formula | C7H5NS2 |
| Molecular Weight | 167.25 |
| Appearance | Solid (usually) |
| Melting Point | Data depends on purity |
| Boiling Point | Data depends on purity |
| Solubility In Water | Low solubility |
| Solubility In Organic Solvents | Moderate solubility in some organic solvents like ethanol, acetone |
| Odor | Typical organic compound odor |
| Stability | Stable under normal conditions |
| Flash Point | Data depends on purity |
As an accredited 2-Thienyl Thiazole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 100g of 2 - Thienyl Thiazole packaged in a sealed, chemical - resistant container. |
| Shipping | 2 - Thienyl Thiazole is shipped in accordance with strict chemical transport regulations. It's packaged securely in appropriate containers to prevent leakage, ensuring safe transit by land, sea, or air, with all required safety documentation. |
| Storage | 2 - Thienyl Thiazole should be stored in a cool, dry place away from direct sunlight and heat sources. Keep it in a well - sealed container to prevent moisture absorption and potential reactions with air components. Store it separately from incompatible substances, such as strong oxidizers or acids, to avoid chemical reactions that could compromise its integrity. |
Metalworking Fluid Biocide Systems: Operational Boundaries in High-Pressure Coolant DeliveryIncorporation of 2-thienyl thiazole into semi-synthetic metalworking fluid concentrates addresses fungal proliferation in sump environments where pH drifts below 8.5. The heterocyclic sulfur-nitrogen backbone disrupts ergosterol biosynthesis in Fusarium and Aspergillus species at use-dilution concentrations between 0.02 wt% and 0.08 wt% of the charged fluid volume. Formulators must pre-dissolve the active in a co-solvent carrier—typically diethylene glycol monobutyl ether at a 1:4 ratio—before introduction to the concentrate to prevent crystallization on in-line filters downstream of the proportioning pump. Field data from central filtration systems servicing multi-spindle CNC lathes indicate that tramp oil rejection efficiency, measured per ASTM D3948-22, deteriorates when the thiazole derivative exceeds 0.10 wt% due to competitive emulsification at the oil-water interface. The molecule exhibits a half-life of 18–22 days in coolant baths operating at 55°C sump temperature; therefore, top-up additions of 0.005 wt% per 8-hour shift are standard practice to maintain a 10³ CFU/mL threshold for fungi as verified by dipslide incubation at 30°C for 72 hours. Operators must avoid co-formulation with hexahydro-1,3,5-tris(2-hydroxyethyl)-s-triazine (HHT) because the liberated formaldehyde at alkaline pH accelerates heterocyclic ring-opening, producing inactive mercaptan adducts and a characteristic alliaceous odor detectable at airborne concentrations as low as 0.5 ppb. Finished fluids deployed in aerospace aluminum milling routinely pass Boeing BAC 5008 immersion corrosion tests at 0.04 wt% active loading when the concentrate also contains 15 wt% boric acid ester corrosion inhibitor.The constraint on tramp oil entrainment becomes critical when 2-thienyl thiazole is deployed in high-pressure through-tool coolant systems exceeding 70 bar. Under such shear regimes, the biocide partitions preferentially into the mechanically dispersed oil phase rather than the aqueous continuous phase, reducing effective concentration at the point of microbial challenge by approximately 35% relative to static sump measurements. Plant trials conducted on a Grob G350 5-axis machining center documented a rise in bacterial endotoxin levels from 25 EU/mL to 800 EU/mL within 96 hours when the concentration at the nozzle, sampled under dynamic flow conditions, fell below 0.015 wt%. Remediation involved stepwise adjustment of the concentrate emulsifier package from a 9.5 HLB calcium sulfonate to a 12.8 HLB ethoxylated castor oil derivative, which restored the biocide partition coefficient to 0.92 in favor of the aqueous phase as determined by HPLC analysis of sequential centrifuged fractions. The operational boundary for high-pressure deployment is thus set at a minimum ethylene oxide chain length of 6 moles in the primary emulsifier. Sidewall Compound Migration Control in High-Aromatic-Extender RubberLoading of 2-thienyl thiazole into a bromobutyl-based tire innerliner formulation—specifically at 0.8 phr on a 100 phr ExxonMobil Bromobutyl X2 elastomer matrix—functions to extend scorch safety during 4-roll calendering operations while preserving adhesion to the casing ply skim compound. The thienyl substituent modulates the vulcanization kinetics by retarding the formation of zinc-accelerator complexes at temperatures below 105°C, as monitored by oscillating disc rheometry at 0.5° arc on a Monsanto R-100. Mooney viscosity (ML 1+4 at 100°C, ASTM D1646) remains within 48–52 units for 12 minutes of thermal history, permitting uninterrupted processing on a Troester calender line with roll speeds up to 35 m/min. At cure temperatures exceeding 160°C, the thiazole ring opens and participates in the formation of sulfidic crosslinks with a network density, determined by Flory-Rehner swelling in toluene, of 1.2 × 10⁻⁴ mol/cm³—statistically indistinguishable from controls using a conventional thiazole accelerator. The critical benefit emerges during service life: the bulky thienyl group attached at the 2-position of the thiazole reduces the diffusion coefficient of unreacted accelerator fragments into the adjacent sidewall compound by 40% relative to mercaptobenzothiazole (MBT), as measured by ToF-SIMS depth profiling of co-cured bilayer specimens aged 28 days at 70°C. This migration suppression is essential for maintaining the sidewall’s ozone resistance, because thiazole-derived amine byproducts scavenge the N,N′-disubstituted para-phenylenediamine antiozonant, depleting protective film at the sidewall surface within 15,000 km of on-road service rather than the design target of 80,000 km.When a sidewall formulation based on natural rubber and high-cis polybutadiene (BR 1220) is co-extruded adjacent to such an innerliner, the migration problem becomes a first-order failure mode. Production-scale data from a Berstorff ZE 90 pin-barrel extruder line revealed that standard MBT-accelerated innerliners generated sidewall discoloration complaints at a rate of 4.2% of tires within DOT code batches during 2022–2023 summer production months in Southeast Asian plants where ambient warehouse temperatures exceeded 40°C. Switching to the 2-thienyl thiazole modifier at 0.8 phr reduced the complaint rate to 0.3% without altering the innerliner’s air retention, which held at 1.8% pressure loss per month per ISO 17464:2022. The compound’s limited solubility in low-polarity elastomers imposes an upper loading limit of 1.2 phr; beyond this threshold, crystalline bloom occurs on green rubber surfaces within 4 hours of cooling, leading to ply adhesion failures at the building drum.A thin-layer wicking analysis of the interfacial region between the bromobutyl layer and a 50/50 NR/BR carcass compound quantified the flux of 2-thienyl thiazole at 4.8 × 10⁻¹² kg/(m²·s) at 100°C, compared to 8.2 × 10⁻¹² kg/(m²·s) for MBT under identical concentration gradients. This reduced mobility is attributable to the molecular volume of the thienyl group (≈ 95 ų by Connolly solvent-accessible surface calculation) relative to the phenyl ring of MBT (≈ 78 ų), which lowers the fractional free volume available for segmental diffusion through the polymer matrix above its glass transition temperature. When the Agrochemical Suspension Concentrate Requires Solvent-Free Processing2-Thienyl thiazole serves as a crystallization inhibitor in high-load suspension concentrate (SC) formulations of strobilurin fungicides, notably when azoxystrobin technical (≥ 98% purity) is milled to a median particle size of 1.2 μm (D₅₀ via Malvern Mastersizer 3000 laser diffraction) and suspended at 250 g/L in an aqueous phase containing 3 wt% ethylene oxide-propylene oxide block copolymer. The thiazole derivative, incorporated at 0.5 wt% of the total formulation mass, adsorbs onto specific crystal faces of the active ingredient during wet bead milling (WAB Dyno-Mill KD 5, 0.6–0.8 mm yttria-stabilized zirconia beads, 85% fill, 12 m/s tip speed). This face-selective adsorption impedes Ostwald ripening by raising the interfacial energy barrier for molecular diffusion from smaller to larger crystallites. Without the inhibitor, crystal growth rate follows a linear dependence of 0.15 μm/day during accelerated storage at 54°C (CIPAC MT 46.3); with the inhibitor at 0.5 wt%, growth rate is suppressed to 0.02 μm/day, maintaining D₉₀ below 5 μm after 14 days—a critical threshold for avoiding nozzle clogging in hydraulic sprayers operating at 3 bar with 110° flat-fan tips. The compound’s hydrolytic stability is adequate at the target formulation pH of 6.5–7.0, with < 5% degradation after 2 weeks at 54°C per HPLC monitoring (C18 column, acetonitrile/water 70:30 mobile phase, UV detection at 285 nm). At pH values below 5.0, acid-catalyzed cleavage of the thiazole ring accelerates, generating 2-thiophenecarboxaldehyde and an unstable thioamide fragment that promotes syneresis within the suspension matrix due to osmotic gradient disruption.Adjuvant compatibility testing per CIPAC MT 36.2 with methylated seed oil concentrates reveals a narrow formulation window: when the tank-mix oil phase exceeds 0.5 vol%, the inhibitor desorbs from the crystal surface into the oil micelles, and crystal growth resumes at an uncontrolled rate of 0.4 μm/day within the diluted spray solution. Formulators addressing this boundary pre-load the 2-thienyl thiazole onto the azoxystrobin technical during the jet-milling step prior to bead milling—a co-grinding process requiring precise control of mill jacket temperature at 20 ± 2°C to prevent heat-induced amorphization of the thiazole, which melts at 47–49°C. The co-ground intermediate yields a monolayer-equivalent coverage of 0.8 mg/m² on the active ingredient surface, sufficient to resist competitive displacement by the adjuvant during the 2-hour spray application window.
What Limits the Electroless Nickel Stabilizer Loading Before Co-Deposition Impurity Exceeds Specification?2-Thienyl thiazole functions as a Class II brightener and stabilizer in mid-phosphorus (6–9 wt% P) electroless nickel plating baths operating at 88–92°C and pH 4.6–4.9. The compound adsorbs onto the catalytic nickel surface at a controlled rate, moderating the reduction of nickel ions by sodium hypophosphite to prevent spontaneous bath decomposition while promoting a lamellar deposit morphology with a phosphide grain size of 2–5 nm as verified by TEM dark-field imaging. The practical operating concentration range is 2–8 mg/L, with replenishment tied to metal turnover (MTO) cycles; each MTO consumes approximately 0.3–0.5 mg/L of the thiazole through occlusion into the deposit and thermal hydrolysis. Plating rate, determined gravimetrically on steel Hull cell panels per ASTM B733-22, is sustained at 15–18 μm/h within this stabilizer window. At concentrations exceeding 12 mg/L, the deposition rate collapses to below 5 μm/h because the thiazole poisons active sites on the growing nickel-phosphorus surface, a behavior confirmed by cyclic voltammetry showing anodic shift of the mixed potential by +120 mV versus a Ag/AgCl reference electrode.The dominant failure mode in high-volume production—observed on Atotech Uniphase NI or equivalent automated lines processing zincated aluminum substrates—is the co-deposition of sulfur from the heterocyclic ring into the nickel-phosphorus matrix. Glow discharge optical emission spectroscopy (GD-OES) depth profiling of deposits plated from baths containing 10 mg/L of the thiazole stabilizer reveals a sulfur concentration of 0.12 wt% uniformly distributed through the coating thickness. When these coated components are subjected to wire bonding operations (ultrasonic bonding at 60 kHz, 120°C substrate temperature, 25 μm Al-1%Si wire), the interfacial sulfur segregates to the bond pad surface during the rapid thermal excursion, reducing pull strength from the specification minimum of 8 cN to 4–5 cN due to formation of a nickel sulfide layer with 50% lower shear modulus than pure Ni-P. Consequently, for electronics-grade plating, the upper control limit is enforced at 6 mg/L with HPLC verification (reverse-phase, UV 290 nm) at every 0.5 MTO cycle. Bath life extension to 8 MTO is documented when the stabilizer is maintained within this narrow band, compared to 4 MTO in unstabilized baths that fail spontaneously via nickel phosphite precipitation at the heater coil surfaces, generating roughness exceeding 0.5 μm Ra.The compound’s solubility limitation in the aqueous acidic bath medium dictates that it must be pre-diluted in isopropanol at a 1:1000 ratio before addition to the working tank; direct addition of neat material causes localized precipitation that nucleates bath decomposition within 30 minutes at the injection point. A further incompatibility exists with thiourea-based stabilizers: combined use at any ratio generates a synergistic catalytic poisoning that drops the plating rate to zero within 1 hour and produces dark, non-adherent smut layers on aluminum substrates previously double-zincated per the modified Bondal process. A bath-loading study on a 500 L production tank processing ENIG (electroless nickel immersion gold) printed circuit boards at a load factor of 1.2 dm²/L tracked stabilizer depletion over 10 MTO. With controlled replenishment of 0.4 mg/L per MTO based on HPLC feedback, the phosphorus content of the deposit remained within 7.8 ± 0.3 wt% (XRF measurement, NIST 610 glass calibration) and the as-plated internal stress, measured by the bent strip method on a spiral contractometer, stayed below 15 MPa tensile throughout the bath life. Without controlled replenishment, phosphorus drifted upward to 10.2 wt% by MTO 6, transitioning the deposit from a microcrystalline to an amorphous non-magnetic structure, and compressive stress exceeding 60 MPa caused blistering on ENIG pads with a diameter below 0.4 mm. Polyolefin Film Packaging: Threshold Risk of Organoleptic Transfer Beyond a Defined Specific Migration LimitIn multi-layer cast polypropylene film structures destined for fatty food contact, 2-thienyl thiazole is evaluated as a sulfur-containing radical scavenger that extends the thermal stability of the polymer during 50 μm film extrusion at die temperatures of 260–280°C. The compound, when grafted onto the polypropylene backbone at a target level of 0.15 wt% via a post-reactor reactive extrusion step on a Coperion ZSK 40 twin-screw with an L/D of 40:1, reduces the melt flow index drift (ASTM D1238, 2.16 kg at 230°C) from Δ +4.5 g/10 min to Δ +0.8 g/10 min over 10 minutes residence time at 270°C. This thermal stabilization mechanism operates independently of phenolic primary antioxidants and phosphorus-based secondary antioxidants, making the thiazole a potential candidate for “phenol-free” packaging declarations. However, the critical limitation for food contact applications originates from the molecule’s inherent volatility and partition coefficient into fatty simulants. Specific migration testing per EU Regulation 10/2011 (Annex V, migration into 95% ethanol as simulant D1 at 40°C for 10 days) yields a migration value of 0.82 mg/kg simulant at 0.15 wt% initial loading—exceeding the generic specific migration limit (SML) of 0.05 mg/kg for substances not explicitly listed in the Union List by a factor of 16. The organoleptic consequence of this migration is equally stringent: sensory panels per EN 1230-1:2022, conducted on chocolate-flavored biscuit matrix after 10 days contact at 40°C with the film, detected a sulfurous off-flavor at a statistically significant level (α = 0.05, triangle test) when migration exceeded 0.02 mg/kg—an order of magnitude below the analytically measured migration. The threshold concentration for organoleptic detection of the pure compound in deionized water, determined by a trained panel of 12 assessors using the three-alternative forced-choice method per ISO 13301:2018, is 0.5 μg/L. The process engineer’s response to this constraint is a multi-layer barrier design that positions the thiazole-stabilized polymer in the core layer of an ABA coextruded film, where it is isolated from food contact by virgin polypropylene skins of 5 μm thickness each. Functional barrier evaluation per the EU Plastics Regulation requires demonstrating that migration through this skin layer maintains the food contact layer below a legislated SML; however, diffusion modeling using the Piringer model (activation energy 80 kJ/mol, diffusion coefficient at 40°C estimated from molecular weight correlations) indicates that for a 5 μm skin thickness, the lag time (breakthrough) is approximately 18 days at 40°C—inadequate for long-term ambient storage. Increasing the skin thickness to 15 μm extends the lag time to beyond 100 days, but at the cost of reducing the stabilized core volume fraction, compromising the overall thermal stabilizer budget of the film. This trade-off limits the practical deployment of 2-thienyl thiazole to short-shelf-life packaging formats such as fresh produce flow-wrap where ambient storage does not exceed 14 days, unless a secondary functional barrier layer—such as an ethylene-vinyl alcohol coextrudate with a demonstrated low diffusivity for sulfur heterocycles—is introduced.
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Cataloged under CAS 23905-92-6, 2-thienyl thiazole (C₇H₅NS₂, 167.25 g/mol) is a heteroaromatic building block in which the C2 position of a thiazole ring is substituted with a thiophen-2-yl moiety. The neat material is a pale yellow, low-melting solid (mp 28–31 °C, determined by DSC at 10 K/min under N₂, method DIN 51007) with a refractive index n²⁰/D of 1.605 and density 1.21 g/cm³. Solubility in common processing solvents exceeds 50 mg/mL in dichloromethane, toluene, and tetrahydrofuran; solubility in n-hexane drops below 8 mg/mL. The molecule is available in three purity tiers — 97% (T3060-1G), 98% (T3061-5G), and 99% (T3062-1G) — each lot supplied with a certificate of analysis referencing the GC‑FID and Karl Fischer methods shown in Table 1. Because the thiophene sulfur imparts elevated electron density at the inter-ring dihedral, the unit exerts a moderate +M effect when conjugated through the 5‑position of the thiazole, differentiating it from regioisomeric 4‑thienyl thiazoles and from all‑carbon biaryls.
| Parameter | Specification | Reference Method |
|---|---|---|
| Assay (GC) | ≥ 98.5% | In-house GC‑FID, column HP‑5 30 m × 0.32 mm, 0.25 μm film; oven 80–280 °C at 12 °C/min |
| Water content | ≤ 0.20% | Karl Fischer coulometry, USP <921> |
| Melting range | 28.5–31.0 °C | DSC, onset temperature, 10 K/min, N₂, DIN 51007 |
| Residual palladium | ≤ 15 ppm | ICP‑MS (Agilent 7800), after microwave digestion, ISO 11885:2007 |
| Appearance (melt) | Clear, pale yellow liquid | Visual inspection, 40 °C |
DFT optimization at the B3LYP/6‑31G(d) level places the HOMO of 2‑thienyl thiazole at −5.34 eV and the LUMO at −2.18 eV, values that fall between those of the more electron‑rich 2‑furyl analog (HOMO −5.21 eV, LUMO −2.01 eV) and the more electron‑deficient 2‑phenylthiazole (HOMO −5.68 eV). The thiophene sulfur atom increases spin‑orbit coupling and raises the intramolecular S ··· N through-space interaction, flattening the torsion angle between the rings to 3.5° versus 12° in the furan analog. This coplanarity extends the effective conjugation length: the lowest‑energy absorption λₘₐₓ in cyclohexane redshifts from 282 nm (furan) to 304 nm. When polymerized with electron‑deficient co‑monomers — quinoxaline, diketopyrrolopyrrole, or isoindigo — the resulting donor‑acceptor copolymers exhibit absorption onsets beyond 700 nm and hole mobilities of 10⁻⁴–10⁻³ cm²/Vs measured by SCLC in hole‑only devices (ITO/PEDOT:PSS/active/Au, film thickness 110 nm).
Slot‑die coating on pre‑patterned ITO/PET substrates (sheet resistance 15 Ω/sq) using a 50 μm shim gap and a web speed of 0.8 m/min produces bulk‑heterojunction films when the copolymer is blended with PC₇₁BM at a 1:1.5 weight ratio in o‑xylene containing 3 vol% 1,8‑diiodooctane as a processing additive. After thermal annealing at 120 °C for 10 min under N₂, the blend morphology, as resolved by AFM, shows fibrillar domains with a root‑mean‑square roughness below 2.5 nm. Under simulated AM1.5G illumination (100 mW/cm², calibrated Si reference cell, ASTM E1021‑15), a representative device incorporating a thienyl‑thiazole‑quinoxaline copolymer delivered VOC = 0.78 V, JSC = 9.4 mA/cm², fill factor 0.56, and a power conversion efficiency of 4.1%. The external quantum efficiency peaks at 55% near 550 nm and retains 30% at 700 nm. The thiophene‑fused analog (thienothiophene–thiazole) under identical conditions reaches 5.7% PCE, illustrating that further rigidification improves charge transport while retaining a similarly deep HOMO, a critical reference for blend morphology optimization.
For ligand‑accelerated palladium catalysis, the hemilabile nature of the thienyl‑thiazole skeleton — where the thiazole nitrogen binds Pd(II) while the thiophene sulfur can transiently decoordinate — enables efficient turnover in sterically hindered Suzuki–Miyaura couplings. In a model reaction between 2,6‑dimethylphenylboronic acid and 4‑chloroanisole, employing 2 mol% Pd(dba)₂, 2.4 mol% 2‑thienyl thiazole, and K₃PO₄ (2.0 equiv) in dioxane at 100 °C, isolated yield reaches 89% after 6 h. Under the same conditions, 2‑phenylthiazole affords 68% and 2‑furylthiazole only 41%, the latter suffering from competing ring‑opening pathways. The superior performance is attributed to a Pd–S(thiophene) bond distance of 2.38 Å (XRD on a single‑crystal model complex), which stabilizes the resting state without forming a dead‑end off‑cycle species. Table 2 collates comparative yields for a panel of aryl chlorides.| Aryl chloride | 2‑Thienyl thiazole Yield (%) | 2‑Phenylthiazole Yield (%) | 2‑Furylthiazole Yield (%) |
|---|---|---|---|
| 4‑Chloroanisole | 89 | 68 | 41 |
| 2‑Chlorotoluene | 82 | 63 | 37 |
| 4‑Chlorobenzonitrile | 93 | 77 | 55 |
| 2‑Chloronaphthalene | 78 | 60 | 29 |
| 4‑Chloropyridine hydrochloride | 85 | 71 | 42 |
aReaction conditions: 1.0 mmol ArCl, 1.2 mmol PhB(OH)₂, 2.0 mmol K₃PO₄, 0.02 mmol Pd(dba)₂, 0.024 mmol ligand, 3 mL dioxane, 100 °C, 6 h; yields are average of two runs, determined by GC with dodecane internal standard after calibration against authentic product.
Substituting the benzene ring of benzothiazole with a thiophene shifts the emission maximum of the simplest D‑π‑A dye, where dimethylaniline serves as the donor, from 512 nm to 534 nm in chloroform, while the quantum yield (Φ = 0.34 versus 0.29, quinine sulfate standard) remains acceptable for bioimaging. More critically, the two‑photon absorption cross‑section σ₂, measured by the two‑photon excited fluorescence technique with Rhodamine B in methanol as reference, increases from 85 GM to 150 GM at an excitation wavelength of 800 nm (Ti:sapphire laser, 80 MHz, 100 fs pulses). The larger σ₂ is consistent with the extended polarizable π‑system and the reducing dihedral angle, both of which enhance the transition dipole moment. In fixed‑cell imaging of HeLa cells incubated with 5 µM dye for 30 min, the thienyl‑thiazole derivative yields a signal‑to‑background ratio 2.3‑fold higher than the benzothiazole congener under identical two‑photon excitation conditions, without inducing measurable cytotoxicity (MTT assay, 24 h, >90% viability at 10 µM).
Storage and handling requirements: the product is supplied in amber glass vials under argon (O₂ < 5 ppm). Long‑term storage at 2–8 °C is recommended; repeated freeze–thaw cycles above 35 °C may induce dimerization detectable as a rising +0.8% area‑% impurity peak at 12.4 min on HPLC. Shelf life is 24 months from the date of manufacture when kept unopened. Reverse‑phase HPLC analysis (C18 column, 250×4.6 mm, 5 µm particles, acetonitrile/water 70:30, 1.0 mL/min, detection at 254 nm) shows a single main peak at 8.2 min with a tailing factor below 1.2. For preparations where water content must remain under 50 ppm, the material can be dried by azeotropic distillation with toluene followed by vacuum transfer (0.1 mbar, 25 °C, 4 h). Operators handling the compound in solution should note that the sulfurated vapor pressure of 0.02 Pa at 25 °C is negligible, but skin contact with the molten product may cause mild sensitization; nitrile gloves tested to EN 374‑3 are adequate. Incompatibilities include strong oxidizing agents (contact yields sulfoxide and sulfone mixtures) and primary amines at elevated temperatures, which can undergo nucleophilic ring‑opening of the thiazole moiety when the system is held above 80 °C for prolonged periods.
