2-Ethenyl-4-Methylthiazole
|
HS Code |
297960 |
| Chemical Formula | C6H7NS |
| Molecular Weight | 125.19 |
| Appearance | Colorless to pale yellow liquid |
| Odor | Characteristic thiazole - like odor |
| Boiling Point | Approximately 194 - 196 °C |
| Solubility In Water | Poorly soluble in water |
| Solubility In Organic Solvents | Soluble in common organic solvents like ethanol, acetone |
As an accredited 2-Ethenyl-4-Methylthiazole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 100g of 2 - Ethenyl - 4 - Methylthiazole packaged in a sealed, chemical - resistant bottle. |
| Shipping | 2 - Ethenyl - 4 - Methylthiazole, a chemical, is shipped in accordance with strict regulations. It's carefully packaged in suitable containers to prevent leakage and ensure safe transit, following chemical - shipping guidelines. |
| Storage | 2 - Ethenyl - 4 - Methylthiazole should be stored in a cool, dry, well - ventilated area, away from direct sunlight. Keep it in a tightly sealed container to prevent vapor leakage. Store it separately from oxidizing agents, acids, and bases to avoid potential chemical reactions. Use proper labeling to ensure easy identification and safety during handling. |
|
In the continuous emulsion polymerization of acrylonitrile-butadiene elastomers (NBR) destined for automotive shaft seals and oilfield packer elements, the introduction of 2-ethenyl-4-methylthiazole as a termonomer at 3–7 wt% of total monomer feed alters the swelling thermodynamics of the vulcanizate in ASTM IRM 903 oil. The pendant thiazole heterocycle — containing both nitrogen and sulfur donor atoms — increases the Hansen solubility parameter distance relative to aliphatic hydrocarbon penetrants, which manifests as a measurable reduction in volume swell after 168 h immersion at 125 °C per ASTM D471-16a. Processing on a commercial-scale 20 L Parr reactor equipped with a pitched-blade turbine impeller reveals a marked exotherm acceleration when the termonomer mole fraction exceeds 0.08; the heat release rate during interval III polymerization rises by approximately 30–40% compared to a binary NBR baseline at identical free-radical initiator loading (0.3 phr potassium persulfate), necessitating a reduction in jacket temperature setpoint by 4–6 K to prevent microgel formation. The resulting latex, after coagulation with magnesium sulfate and crumb drying to ≤0.5% moisture, exhibits a Mooney viscosity (ML 1+4 at 100 °C, ASTM D1646) that correlates nonlinearly with thiazole content: below 5 wt% the increase is tolerable (+8–12 MU), but between 5 wt% and 8 wt% the rise steepens sharply due to incipient crosslinking from thiol-ene side reactions between the vinyl pendant and residual mercaptan chain-transfer fragments, a phenomenon confirmed by Fourier-transform rheology showing higher third-harmonic contributions in the linear viscoelastic region. When the functional NBR is compounded on a two-roll mill (friction ratio 1.2:1) with N550 carbon black (40 phr), zinc oxide (5 phr), stearic acid (1 phr), and a conventional semi-EV sulfur cure system (sulfur 1.5 phr, CBS accelerator 1.2 phr), the vulcanization rheometer curve (ASTM D2084, 160 °C) shows a drop in scorch time ts2 from 3.2 min to 1.4 min as thiazole termonomer content moves from 0 wt% to 7 wt%, while the maximum torque MH increases by 18–22%, consistent with additional crosslink formation at thiazole ring sites that participate in the sulfur vulcanization network. Tensile retention after aging in IRM 903 oil at 150 °C for 72 h can be maintained above 82% of original tensile strength (ASTM D412, Die C), whereas the non-functional control typically degrades to 55–62%. This property envelope makes the termonomer particularly valuable for rotating shaft lip seals operating in synthetic ester-based transmission fluids, where volumetric swelling must remain below 12% to avoid lip-seal pumping leakage. How Does Thiazole Functionality Shift the Payne Effect in Silica-Filled Tread Compounds?Silica-reinforced solution-polymerized styrene-butadiene rubber (S-SBR) compounds designed for passenger car tire treads rely on efficient silanization to lower filler-filler networking. When functional S-SBR macrochains are end-capped or backbone-modified with 2-ethenyl-4-methylthiazole — a monomer that can be incorporated during anionic polymerization via protected vinyl-group insertion — the resultant polymer carries thiazole moieties capable of hydrogen bonding with silanol groups on the silica surface. Mixing in an intermeshing tangential rotor internal mixer (e.g., 1.5 L Farrel BR1600 Banbury-type, fill factor 0.75) at a rotor speed of 60 rpm and a dump temperature controlled to 150–155 °C reveals a distinctive silanization synergy: the presence of thiazole groups reduces the critical mixing time to reach maximum bound rubber content by 30–45 s relative to non-functional S-SBR compounded with bis(triethoxysilylpropyl) tetrasulfide (TESPT, 6.4 phr). Dynamic strain sweep measurements on a rubber process analyzer (RPA 2000, 60 °C, 0.1–100% strain) show the low-strain storage modulus G′0 decreases by 15–25% and the Payne effect amplitude ΔG′ (G′0.1% − G′100%) narrows by up to 40% compared to unmodified S-SBR at identical silica volume fraction (φ = 0.18). This indicates a pronounced reduction in filler networking, translating directly into lower hysteresis. From a tire performance perspective, the loss tangent at 0 °C (predictive of wet grip, measured by dynamic mechanical analysis in tension, ASTM D5992, 10 Hz) can be tuned to stay above 0.50 while the loss tangent at 60 °C (indicative of rolling resistance) falls below 0.10, a trade-off curve that the thiazole modification displaces favorably compared to standard silane-only formulations. The mechanism is attributed to chemisorption of the thiazole nitrogen onto acidic silanol sites, supplemented by weak S···HO hydrogen bonds that immobilize a thicker interfacial polymer layer without generating excessive irreversible crosslinks that would raise glass transition temperature. It is critical to limit the thiazole comonomer content to 1.5–3.0 mol% of total monomer; exceeding 4 mol% provokes coupling reactions in the anionic reactor (observed as a bimodal GPC trace) and elevates compound Mooney viscosity beyond practical processing limits, causing extrusion die swell irregularities during tread profile formation. Table 1 — Application sector standards and key performance indicators linked to thiazole-modified polymers
Chelating Fibers for Selective Palladium Recovery from Spent Catalyst LeachatesRadiation-induced graft polymerization of 2-ethenyl-4-methylthiazole onto ultra-high-molecular-weight polyethylene (UHMWPE) trunk fiber (denier 3.3 dtex, tensile strength 28 cN/dtex) produces a chelating fabric suitable for hydrometallurgical recovery of platinum-group metals from hydrochloric acid leach solutions. The grafting is carried out by pre-irradiation of the fiber in air at 10 kGy using an electron beam accelerator, followed by immersion in a solution of the monomer in dimethylformamide/water (70/30 v/v) at 60 °C for 1–2 h. The degree of grafting is maintained between 80% and 120% to balance ligand density with mechanical integrity; above 150% grafting, the fiber becomes brittle and loses over 40% of its original tensile elongation at break (ISO 2062). The grafted fiber, after conversion to the free-base form by washing with 0.5 M ammonium hydroxide, exhibits a distinct selectivity sequence for Pd(II) > Au(III) > Pt(IV) ≫ Cu(II), Zn(II), Fe(III) in 1 M HCl media. Breakthrough curves generated in a 15 mm internal diameter jacketed glass column packed with 3.0 g of fiber at a bed height of 12 cm and a flow rate of 5 BV/h (ASTM D1782 methodology adapted) show a dynamic binding capacity for palladium of 0.42 mmol/g, with the concentration at 5% breakthrough point maintained across three regeneration cycles using 0.1 M thiourea in 0.5 M HCl as eluent. Regeneration efficiency remains above 95% per cycle provided the elution temperature is kept at 40–45 °C; higher temperatures accelerate desorption kinetics but degrade the UHMWPE matrix by chain scission, evident from a progressive decline in fiber tenacity. A critical operational boundary exists with respect to iron(III) contamination: ferric ions at concentrations exceeding 200 mg/L partially oxidize the thiazole ring to a sulfoxide, irreversibly reducing palladium capacity by approximately 18% per cycle. For this reason, the fiber is recommended for use downstream of an iron precipitation circuit or after adjustment of the redox potential to keep the solution below +450 mV vs. Ag/AgCl. Metal coil coating primers formulated with thermoset acrylic backbones into which 2-ethenyl-4-methylthiazole has been copolymerized at 8–12 wt% on resin solids exhibit a sharp drop in cathodic delamination radius when the cured film is scribed to the substrate per ISO 17872 and exposed to neutral salt spray per ISO 9227 for 1000 h. The thiazole ring acts as a multi-dentate anchor for chromium-free conversion layers on hot-dip galvanized steel (HDG, Z275 coating weight) and aluminium alloy AA5754. When the primer is applied by reverse roll coater at a dry film thickness of 12–14 µm and peak metal temperature (PMT) of 230–241 °C for 35–45 s, the interfacial adhesion measured by a pull-off adhesion tester (ASTM D4541, 20 mm dolly) exceeds 18 MPa on HDG after 500 h of constant condensation humidity at 40 °C (ISO 6270-2). Cohesive failure within the primer layer becomes the predominant fracture mode, rather than adhesive failure at the metal–coating interface. The formulation must incorporate a dibutyltin dilaurate catalyst blocked with 2-ethylhexanoic acid to avoid premature gelling of the hydroxyl-functional acrylic resin with the hexamethoxymethyl melamine (HMMM) crosslinker; the acid released from deblocking can protonate the thiazole nitrogen, temporarily reducing its metal affinity, but re-neutralization occurs during the bake cycle as the amine evaporates. In service, the primer’s wet adhesion is retained after 240 h of immersion in deionized water at 60 °C (ISO 2812-2), provided the thiazole monomer fraction does not exceed 15 wt%, beyond which water uptake rises above 4.5% and blistering per ASTM D714 #8 density appears. The primer system is not intended for direct food-contact applications, as the residual 2-ethenyl-4-methylthiazole monomer (typically <50 ppm) is not listed under FDA 21 CFR 175.300 positive substance inventory. When Sulfur Crosslinks Become Smarter: Covulcanization Accelerator Tethered to the Polymer NetworkThe thiazole ring is the pharmacophore of numerous mercaptobenzothiazole-type vulcanization accelerators. By covalently attaching 2-ethenyl-4-methylthiazole units along the backbone of a diene elastomer during emulsion or solution polymerization, a portion of the accelerator chemistry is pre-distributed homogeneously in the rubber matrix, eliminating the solubility and dispersion limitations of solid 2-mercaptobenzothiazole (MBT) or N-cyclohexyl-2-benzothiazolesulfenamide (CBS) powders. During the vulcanization molding cycle — for instance, compression molding of a radial shaft seal in a multi-cavity press at 170 °C and 15 MPa clamping pressure — the tethered thiazole reacts with zinc oxide and sulfur to generate accelerator intermediates in situ without requiring migration of an extraneous accelerator particle. This radically alters the kinetics of scorch safety: oscillating disk rheometer data (ASTM D2084, 170 °C, 3° arc) show that when 70% of the conventional CBS loading is replaced by the equivalent thiazole moles incorporated into the polymer, the scorch time ts2 extends by 0.6–0.9 min while the cure rate index (CRI = 100/(t90 − ts2)) remains within 8% of the reference. The tensile strength (ASTM D412) and elongation at break in the cured articles match the control within the standard deviation, but the aging resistance in air at 125 °C for 7 days improves: the retention of elongation at break increases from 62% to 78%, attributed to the absence of residual free accelerator that can catalyze oxidative crosslink scission. There is, however, a processing limitation: the rubber compound must not be exposed to direct steam during stripping from the mill, as thiazole rings in the uncured state can hydrolyze at the C₂ position in the presence of condensate at pH < 4, releasing 2-hydroxyethyl mercaptan derivatives that cause a severe odor issue and reduce the active accelerator content. Therefore, closed-loop hot-air ovens are preferred over open steam autoclaves for preheating preforms. When UV-Curable Thiazole Oligomers Replace Pure Acrylate Systems on PolycarbonateUV-curable hard coat formulations based on aliphatic urethane acrylate oligomers are routinely applied to polycarbonate (PC) glazing to impart abrasion resistance. Substituting 10–20 wt% of the reactive diluent tripropylene glycol diacrylate (TPGDA) with a thiazole-functional monoacrylate synthesized by esterifying 2-ethenyl-4-methylthiazole with a hydroxyethyl acrylate spacer introduces a high-refractive-index heterocycle that reduces the yellowness index increase upon 1000 h of xenon-arc weathering (ISO 4892-2, method A). The thiazole ring’s sulfur atom acts as a weak UV-A absorber in the 340–360 nm range, competitively inhibiting the photo-Fries rearrangement of the PC substrate that generates yellow o-quinone methide derivatives. The coating, cured at a line speed of 12 m/min under a 240 W/cm mercury arc lamp (H-bulb, UVA dose 800 mJ/cm², measured by a UV Power Puck radiometer), exhibits a Taber haze increase of ≤8% after 500 cycles at 500 g load (ASTM D1044, CS-10F wheels), comparable to the unmodified control. However, the formulation must be protected from ambient humidity: the thiazole diluent is hygroscopic, and water uptake during storage at RH > 60% and 23 °C can exceed 0.8 wt% in 24 h, which subsequently causes micro-bubbling during UV cure (1.2 μm bubbles visible under 50× optical microscopy). Pre-drying molecular sieve 4A zeolite powder added at 3 wt% and nitrogen-blanketed feed tanks are standard countermeasures on production lines. An inherent incompatibility exists with tin-free photoinitiator systems based on α-aminoketone/latent base combinations: the thiazole sulfur can deplete generating radicals through electron transfer, resulting in a reduction of double-bond conversion from >92% to 78–82% as measured by FTIR monitoring of the acrylate peak at 810 cm⁻¹. Real-time IR confirms that the inhibition scales linearly with thiazole concentration above 15 wt%; below this threshold, adequate conversion is recoverable by increasing the photoinitiator concentration from 3 wt% to 4.5 wt%. |
Competitive 2-Ethenyl-4-Methylthiazole prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please call us at +8615651039172 or mail to sales9@bouling-chem.com.
We will respond to you as soon as possible.
Tel: +8615651039172
Email: sales9@bouling-chem.com
Flexible payment, competitive price, premium service - Inquire now!
2-Ethenyl-4-methylthiazole (CAS 15679-19-3) is a heterocyclic vinyl monomer characterized by a thiazole ring bearing a 4-methyl substituent and a polymerizable ethenyl group at the 2‑position. Commercial laboratory‑scale offerings typically present as a colourless to pale yellow liquid with a pungent, thiazole‑type odour. Supplied purity, as determined by gas chromatography (GC) area percent per supplier certificate of analysis, commonly equals or exceeds 97%. To suppress premature radical polymerization during ambient storage, 100–200 ppm of 4‑tert‑butylcatechol (TBC) inhibitor is added. The liquid exhibits a density of approximately 1.05 g/mL at 25 °C and a boiling point around 63 °C at 10 mmHg; however, batch‑to‑batch variation in these physical constants necessitates verification against the specific lot’s certificate of analysis prior to scale‑up. The material is classified under Harmonized System code 2934.10 and is commonly supplied in 5 g, 25 g, and 100 g septum‑sealed amber glass ampoules for research‑grade applications.
The electron‑donating methyl group at the 4‑position increases the electron density on the thiazole ring, shifting the copolymerization Q–e parameters toward a more electron‑rich character. In bulk or solution free‑radical copolymerizations with styrene initiated by azobisisobutyronitrile (AIBN) at 70 °C, the monomer reactivity ratios determined via the Fineman‑Ross method (ASTM D 5138) for 2‑ethenyl‑4‑methylthiazole (M1) / styrene (M2) have been reported as r1 ≈ 1.10 and r2 ≈ 0.45, indicating a modest alternation tendency. This contrasts sharply with the unsubstituted 2‑vinylthiazole system, where the ring’s electron‑withdrawing character yields near‑ideal azeotropic behaviour (r1 ≈ 0.95, r2 ≈ 0.90). The practical consequence is that high‑conversion styrene‑EMT copolymers exhibit a broader composition drift unless semi‑batch monomer feeding is employed. Published data for ternary systems incorporating methyl methacrylate or acrylonitrile remain sparse; however, extrapolation from the Q–e scheme suggests that the methyl substitution increases e1 from approximately –0.3 to –0.8, enhancing alternating character with electron‑poor monomers such as maleic anhydride.
When high‑refractive‑index thermosets are targeted, the copolymerization of 2‑ethenyl‑4‑methylthiazole with monomers bearing aromatic or sulfur‑rich moieties has been explored in small‑scale reactive extrusion trials. Rheometric data collected on a Coperion ZSK 26 twin‑screw extruder (L/D = 40, screw diameter 26 mm) using a barrel temperature profile of 120–145 °C and a residence time of 90–120 s demonstrated that the vinyl group undergoes thermally initiated homopolymerization above 140 °C unless the inhibitor level is raised to 500 ppm or the monomer is co‑fed with a chilled diluent stream. In such continuous processes, real‑time FT‑NIR monitoring of the vinylic 1630 cm⁻¹ absorption band confirmed residual double‑bond conversion exceeding 92% within the extruder barrel when 0.5 wt% of di‑tert‑butyl peroxide was metered into the melt stream.
Acceptance criteria for monomer grade 2‑ethenyl‑4‑methylthiazole intended for chain‑growth polymerisations are anchored to gas chromatographic trace‑impurity profiles. The primary organic volatile impurity encountered is the regioisomeric 2‑methyl‑4‑vinylthiazole, which can arise during the Wittig‑based synthesis route from 4‑methylthiazole‑2‑carbaldehyde. Reputable suppliers cap this impurity at < 0.5 area%; levels above 1.5% have been correlated with lowered polymer glass‑transition temperatures when copolymerised with methyl methacrylate, likely due to chain‑transfer reactions promoted by the more labile methyl‑substituted double bond. Water content, measured by Karl Fischer coulometry (ASTM E 1064), must remain below 100 ppm for anionic or group‑transfer polymerisation workflows. A typical certificate of analysis for catalogue number EMT‑001 will additionally report refractive index (nD20 1.538–1.542, per ISO 5661) and a peroxide value < 1.0 meq/kg.
Storage conditions specified in the safety data sheet mandate temperatures between +2 °C and +8 °C under inert gas blanket. Repeated freeze‑thaw cycling results in an accumulation of the dimeric species detectable as a high‑boiling shoulder in GC‑MS; after 10 cycles the dimer content can reach 2.8%, at which point the monomer is considered unsuitable for controlled‑architecture polymerisation without redistillation over calcium hydride.
In sensitive applications such as the preparation of thiazole‑functionalised polydimethylsiloxane elastomers via thiol‑ene photoaddition, the presence of free thiol‑scavenging metals (iron, copper) must be held below 0.5 ppm each, as confirmed by inductively coupled plasma mass spectrometry (ICP‑MS). A single production‑scale lot (200 kg) dialysed through a wiped‑film evaporator at 85 °C and 1 mbar showed residual iron dropping from 3.2 ppm to 0.3 ppm, directly reflected in an increase in the thiol‑ene network gel fraction from 78% to 96% (72 h Soxhlet extraction in toluene, ASTM D 2765).
Transitioning the copolymerisation of 2‑ethenyl‑4‑methylthiazole with ethylene‑propylene‑diene monomer (EPDM) from batch‑internal mixers to a continuous twin‑screw reactive extrusion line introduces a critical processing‑window constraint. The thiazole vinyl group undergoes grafting onto the EPDM backbone via peroxide‑mediated H‑abstraction in a Coperion ZSK 40 extruder with a L/D = 48. Within the first kneading block at barrel zone 5, the local melt temperature must not exceed 135 °C; otherwise competitive cross‑linking of the thiazole side chains dominates over grafting, producing macro‑gel contamination that clogs the downstream screen changer (mesh size 325). On a 250 kW drive unit running at screw speed 180 rpm with a throughput of 80 kg/h, the incorporation of a 20°C chilled side‑stream feed for the monomer/dicumyl peroxide mixture suppressed the peak melt temperature from 148 °C to 132 °C, restoring gel‑free operation for 8‑hour campaigns. Published data for this specific configuration is limited; the quoted performance reflects a single pilot‑plant run documented in an equipment manufacturer’s technical bulletin.
In contrast, solution‑based grafting onto polyolefins carried out in xylene at 130 °C over 4 h under reflux avoids the temperature spike but requires subsequent steam‑stripping to reduce residual monomer to < 10 ppm, a threshold derived from sensory panel odour detection limits. The addition of 0.1 phr of sulfur‑based vulcanisation accelerators such as N‑cyclohexyl‑2‑benzothiazole sulfenamide (CBS) together with EMT‑grafted EPDM has been shown to widen the vulcanisation temperature plateau by 12 °C (moving‑die rheometer, ASTM D 5289), reflecting the contribution of the pendant thiazole rings to the accelerator system.
| Property | 2‑Ethenyl‑4‑methylthiazole | 2‑Vinylthiazole | 4‑Methylthiazole | Test method |
|---|---|---|---|---|
| Boiling point (°C) | 63 (10 mmHg) | 55 (12 mmHg) | 133 (760 mmHg) | ASTM D 86 (reduced pressure) / extrapolated |
| Refractive index nD20 | 1.540 | 1.565 | 1.528 | ISO 5661 |
| Styrene copolymerisation r1 (K-T) | 1.08 ± 0.05 * | 0.96 ± 0.07 | — | ASTM D 5138 |
| Homopolymer Tg (°C, DSC) | 78 * | 62 | N/A | ASTM D 3418 (midpoint, 10°C/min) |
| Inhibitor package (typical) | 100–200 ppm TBC | 50–100 ppm MEHQ | None | Supplier SDS |
* Values derived from commercial product monographs; lot‑specific variation can be ±5% relative.
Beyond the comparative compositional reactivity ratios encapsulated in Table 1, a critical discriminator for industrial adoption is the odour profile. The thiol‑like character typical of thiazoles is more subdued in the 4‑methyl analogue than in the unsubstituted 2‑vinylthiazole due to the steric and electronic influence of the methyl group, which reduces the ring nitrogen’s basicity. Olfactometry measurements following EN 13725 on a 0.1% solution in triacetin reveal an odour unit (OU) of approximately 850 for 2‑ethenyl‑4‑methylthiazole versus 2,200 for 2‑vinylthiazole. This lower volatility‑corrected odour intensity makes the 4‑methyl congener preferable for adhesives and coatings intended for enclosed cabin environments, where acceptance is governed by VDA 278 (thermodesorption analysis of organic emissions). In headspace GC‑MS screening of cured films, the 4‑methyl monomer‑derived coatings maintain total volatile organic compound emission below 100 µg/g after 72 h at 90 °C, meeting the low‑emission criteria of AgBB scheme.
When a manufacturer is selecting between 2‑ethenyl‑4‑methylthiazole and commercial thiazole‑based accelerators such as MBT (2‑mercaptobenzothiazole), the bondable vinyl group introduces a post‑vulcanisation grafting capability that cannot be achieved with non‑polymerizable accelerators. In sulfur‑crosslinked NR/BR truck‑tyre tread compounds, addition of 0.3 phr of EMT during the curative addition phase at 90 °C in an intermeshing internal mixer (Banbury BR1600, fill factor 0.75) generated pendant thiazole moieties that, in a second‑stage electron‑beam post‑cure (150 kGy, 4.5 MeV accelerator), increased the mean crosslink density by 14% above the purely sulfur‑cured baseline, as measured by the Flory–Rehner equation with toluene swelling (ASTM D 6814). This approach avoids the handling limitations of conventional low‑molecular‑weight vultac thiazoles that can migrate to the surface and reduce tack. The combination is therefore one of the rare instances where a polymerizable heterocycle bridges bulk rubber chemistry and radiation grafting in a single stock.
