N-(2-Cyanoethyl)Pyrrole
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HS Code |
566513 |
| Chemical Formula | C7H8N2 |
| Molecular Weight | 116.15 g/mol |
| Appearance | Solid (usually) |
| Melting Point | Data needed |
| Boiling Point | Data needed |
| Density | Data needed |
| Solubility In Water | Low solubility (expected) |
| Solubility In Organic Solvents | Soluble in common organic solvents (e.g., ethanol, acetone) |
| Odor | Odorless (usually) |
| Stability | Stable under normal conditions |
| Reactivity | Reactive towards strong oxidizing agents and acids |
As an accredited N-(2-Cyanoethyl)Pyrrole factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | 100g of N-(2 - Cyanoethyl)Pyrrole packaged in a sealed, chemical - resistant bottle. |
| Shipping | N-(2 - Cyanoethyl)Pyrrole is shipped in sealed, corrosion - resistant containers. Adequate cushioning is used to prevent breakage. Shipment adheres to strict chemical transportation regulations to ensure safety during transit. |
| Storage | N-(2 - Cyanoethyl)Pyrrole should be stored in a cool, dry, and well - ventilated area. Keep it away from heat sources, open flames, and oxidizing agents. Store in a tightly sealed container to prevent exposure to air and moisture, which could potentially lead to decomposition or unwanted reactions. Avoid storing near incompatible substances. |
A two-stage oxidative polymerisation sequence is initiated by dissolving 0.10 mol N-(2-cyanoethyl)pyrrole in anhydrous acetonitrile (100 mL) inside a jacketed glass reactor fitted with an anchor agitator and a PTFE-coated thermocouple probe. The solution is cooled to 0–2 °C under a dry nitrogen blanket. Separately, 0.23 mol anhydrous FeCl₃·6H₂O is dissolved in 150 mL deionised water and brought to the same temperature. The oxidant solution is metered into the monomer solution through a peristaltic pump at a constant rate of 2.5 mL·min⁻¹ over 60 min while the agitation speed is held at 250 rpm. Once the addition is complete, the dark slurry is stirred for an additional 4 h at 0–2 °C. The precipitated poly(N-cyanoethylpyrrole) (PNCPy) is collected on a 20 µm polypropylene filter cloth, washed sequentially with 0.1 M HCl (three 200 mL portions), deionised water until the filtrate conductivity drops below 10 µS·cm⁻¹, and a final rinse with acetone to aid drying. Vacuum drying is carried out at 40 °C under 10 mbar for 18 h to yield a free-flowing black powder with a bulk conductivity of 2.5×10⁻² S·cm⁻¹ measured on a pressed pellet by the four-probe van der Pauw method compliant with ASTM F76. For antistatic topcoat formulations, the dried powder is dispersed in N-methyl-2-pyrrolidone (NMP) at a solids loading of 5.0 wt% using a high-shear rotor-stator mixer (8000 rpm, 45 min) and then passed through a triple-roller mill with a gap setting of 5 µm to break down agglomerates to a d₉₀ particle size below 1.2 µm. The dispersion is applied to 125 µm PET film with a wire-wound coating bar delivering a wet film thickness of 10 µm. After forced-air drying at 80 °C for 5 min, the surface resistivity measured per ASTM D257 at 23 ±2 °C and 50 ±5 % RH lands at 1.2×10⁶ Ω/sq, a value that satisfies the IEC 61340-5-1 requirement for protected workstations in earth-bonded ESD flooring. The single most frequent in-plant failure arises from residual iron ions—if the washing protocol is shortened and the dried polymer retains more than 15 ppm Fe3+ as determined by ICP-OES after microwave digestion, galvanic micro-cells form when the coated film is exposed to >75 % RH; a remedial EDTA wash (0.01 M, pH 4.5, 60 °C, 30 min) can lower Fe to 3–5 ppm. A second processing conflict concerns over‑oxidation: beyond 0.25 mol FeCl₃ per mole monomer the pyrrole β‑positions are attacked, raising the optical band gap from 2.8 eV to >3.4 eV and permanently collapsing conductivity. For coated parts going into portable consumer electronics, the blend must also meet EU RoHS 2011/65/EU recast limits on phthalates and brominated flame retardants introduced via substrates or additives.When the nitrile is hydrolysed to a carboxylic acid for tolmetin‑type NSAID intermediates under ICH Q7 conditionsThe transformation is run in a glass‑lined 500‑L vessel under ISO 10605‑conformant earthing. N-(2‑Cyanoethyl)pyrrole (1.0 eq) is charged together with ethanol‑water (1:1 v/v, 6.0 L·kg⁻¹) and sodium hydroxide pellets (2.5 eq). The mixture is heated to reflux (83–85 °C internal) and held for 8 h. Ammonia evolution is scrubbed through a dilute sulfuric acid trap, and the end point is verified by the disappearance of the 2248 cm⁻¹ nitrile stretch on an in‑line ATR‑FTIR probe. After cooling to 25 °C, the pH is adjusted to 2.0–2.2 with 6 M HCl, precipitating 3‑(1H‑pyrrol‑1‑yl)propanoic acid as off‑white crystals. The solid is isolated on a pressure nutsche filter, washed with chilled water (2 vol), and vacuum‑dried at 50 °C/5 mbar to a water content ≤0.5 % (Karl Fischer). Yield: 92 % of theory, with a melting point of 112–114 °C and HPLC purity ≥99.0 area-% at 210 nm. This acid is subsequently activated with thionyl chloride and condensed with substituted benzoyl moieties to assemble the central pyrrole‑acetic acid motif found in non‑steroidal anti‑inflammatory drugs chemically related to tolmetin. Because the hydrolysis employs ethanol as the sole organic solvent, the residual solvent limit in the dried intermediate defaults to ≤5000 ppm under ICH Q3C (R8) Class 3; any acetonitrile carried over from upstream synthesis is capped at 410 ppm (Class 2). The critical impurity to control is unreacted nitrile, which can alkylate nucleophilic sites in the final API; its limit is set at ≤0.15 % by a stability‑indicating HPLC method validated per ICH Q2(R1) on a C18 column (5 µm, 250 mm × 4.6 mm) with acetonitrile‑0.1 % phosphoric acid (30:70) as mobile phase at 1.0 mL·min⁻¹ and detection at 254 nm. Any symmetrically coupled 1,1′‑(dioxo)dipyrrole impurity is held to ≤0.10 %. The impurity profile is summarised below.
When catalytic hydrogenation of the pendant nitrile crosses the 50‑litre thresholdReduction of the nitrile moiety to the primary amine is performed in a 100 L Hastelloy C‑22 autoclave rated to 100 bar at 300 °C and equipped with a magnetic‑drive stirrer. The vessel is charged with 10.0 kg (83.2 mol) N‑(2‑cyanoethyl)pyrrole dissolved in 60 L ethanol (denatured with 2 % toluene) and 1.0 kg Raney® 2800 nickel catalyst slurry (water‑wet, corresponding to 50 wt% dry catalyst). After three nitrogen‑pressure‑purge cycles to achieve an oxygen level below 0.5 vol%, hydrogen is introduced to 35 bar and the jacket is ramped to 55 °C over 45 min. A pronounced exotherm (ΔTad ≈ 180 K) is observed; the cooling system must provide ≥1.5 kW·kg⁻¹ of heat removal capacity, and the hydrogen uptake rate is monitored via a mass‑flow controller to stay below 4.8 mol·min⁻¹. Once the hydrogen consumption ceases (6–8 h), a sample is withdrawn through a dip tube, quenched in dilute HCl, and analysed by in‑line FTIR—the 2248 cm⁻¹ nitrile band must be undetectable. The reactor is cooled, vented, and purged; the catalyst is settled and the supernatant filtered through a 0.5 µm sintered‑metal candle under nitrogen pressure. The filtrate is acidified with ethanolic HCl to pH 2–3, yielding 1‑(3‑aminopropyl)pyrrole hydrochloride as a hygroscopic white solid after solvent evaporation and vacuum drying at 35 °C/1 mbar. Yield exceeds 95 % with a purity by non‑aqueous titration of ≥99.0 %. The amine hydrochloride is used in situ for the synthesis of N‑substituted pyrrole‑carboxamide fungicide candidates; acylation with chloroacetyl chloride in dichloromethane at 0–5 °C in the presence of triethylamine (1.1 eq) gives the chloroacetamide intermediate that is subsequently elaborated to the active ingredient. The entire hydrogenation train must be certified for use in potentially explosive atmospheres under ATEX 2014/34/EU category 2, and the Raney nickel handling area must be equipped with a water‑deluge system because the catalyst is pyrophoric when dry. The most common deviation at pilot scale is incomplete conversion caused by catalyst poisoning from trace cyanide (≤5 ppm) carried over if the nitrile was synthesised via cyanoethylation of pyrrole with acrylonitrile without thorough wash; pre‑treatment of the nitrile with activated charcoal (2 wt%, 25 °C, 4 h) routinely restores catalyst activity.The dibromo derivative is prepared to unlock cross‑coupling chemistry at the pyrrole α‑positions without requiring protection of the nitrile. A 2‑L four‑neck flask fitted with an overhead stirrer, dropping funnel, low‑temperature thermometer and nitrogen inlet is charged with N‑(2‑cyanoethyl)pyrrole (0.50 mol) and dry tetrahydrofuran (800 mL). The solution is cooled to −12 °C (internal) using a dry‑ice–acetone bath. N‑Bromosuccinimide (1.10 mol, 2.2 eq) is added portionwise over 90 min while the temperature is maintained at −10 ± 2 °C. Stirring is continued for 3 h at this temperature, after which the bath is removed and the mixture is allowed to warm to 0 °C. The precipitated succinimide is removed by cold filtration through a Celite pad, and the filtrate is concentrated under reduced pressure at ≤25 °C. The oily residue is diluted with ethanol (200 mL) and refrigerated at −20 °C overnight to yield pale‑yellow needles of 2,5‑dibromo‑N‑(2‑cyanoethyl)pyrrole, melting point 78–80 °C, isolated yield 88 % after recrystallisation from ethanol. 1H NMR (400 MHz, CDCl₃) shows the pyrrole protons as a singlet at 6.49 ppm, confirming symmetrical substitution; elemental analysis demands Br 55.85 %. This crystalline intermediate is stable in air for months and serves as a bifunctional monomer in AA‑BB type Stille or Suzuki polycondensations that produce alternating conjugated polymers with precisely controlled band gaps. In medicinal chemistry, the dibromide undergoes sequential Pd(OAc)₂/XPhos‑catalysed Suzuki couplings with arylboronic acids, first at the less hindered C‑2 position when using 1.0 eq of boronic acid, enabling the synthesis of unsymmetrically substituted pyrroles that are otherwise inaccessible. Residual palladium after coupling is reduced to ≤20 ppm by treatment with trimercaptotriazine‑functionalised silica (10 wt%, 60 °C, 2 h) to meet ICH Q3D oral concentration limits for Pd.How does the pendant nitrile alter the electrochemical band gap of copolymer films on ITO‑PET?Cyclic voltammetric deposition was conducted in a single‑compartment three‑electrode cell containing 0.1 M LiClO₄ in propylene carbonate dried over 4 Å molecular sieves to ≤20 ppm water. The working electrode was an ITO‑coated PET foil (60 Ω·sq⁻¹) masked to expose a geometric area of 2.0 cm²; a platinum mesh served as counter electrode and an Ag/AgCl (3 M NaCl) as reference. The feed solution comprised pyrrole monomer (50 mM) and N‑(2‑cyanoethyl)pyrrole (10 to 40 mol%) to maintain a total monomer concentration of 50 mM. Electrodeposition was carried out potentiostatically at +0.85 V vs Ag/AgCl for a charge density of 100 mC·cm⁻², monitored by a digital coulometer. The resulting thin films were rinsed with acetonitrile and dried under a stream of nitrogen. Optical absorption spectra collected on a diode‑array spectrophotometer with an integrating sphere revealed that incorporation of 40 mol% cyanoethyl‑substituted pyrrole shifts the π‑π* transition maximum from 448 nm (pure polypyrrole) to 511 nm, corresponding to a decrease in the optical band gap from 2.77 eV to 2.43 eV calculated from the Tauc plot. Electrochemical band gaps extracted from the onset potentials of oxidation (Eonset,ox) and reduction (Eonset,red) in 0.1 M TBAPF₆ acetonitrile electrolyte gave a consistent value of 2.38 ±0.05 eV. The electron‑withdrawing nitrile lowers the LUMO level, narrowing the band gap and simultaneously improving the oxidative doping stability: films retained 85 % of their initial charge capacity after 1000 cycles between −0.2 V and +1.0 V at 100 mV·s⁻¹. This behaviour renders the copolymers suitable for flexible electrochromic windows operating in the visible–NIR range, though the electrochromic contrast degrades if the film thickness exceeds 150 nm because the cyanomethyl‑substituted chains develop micro‑cracks during the ion‑insertion swelling cycle; a thickness of 110 ±15 nm measured by profilometry (stylus force 1 mg, DIN EN ISO 3274) was identified as the optimal balance between optical density and mechanical integrity.Cathodic polarisation shift induced by N-(2-cyanoethyl)pyrrole in acidic copper electroplating bathsGalvanostatic Hull cell tests (267 mL, 2 A, 5 min, air‑agitated) were performed in a virgin‑makeup solution consisting of CuSO₄·5H₂O (200 g·L⁻¹), H₂SO₄ (50 g·L⁻¹), chloride ion (60 mg·L⁻¹ as NaCl), and a polyalkylene glycol suppressor (300 mg·L⁻¹). The addition of N‑(2‑cyanoethyl)pyrrole at concentrations between 5 mg·L⁻¹ and 40 mg·L⁻¹ systematically increased the cathodic overpotential in the high‑current‑density zone (3–6 A·dm⁻²) by 45–90 mV, as monitored by a Luggin capillary connected to a saturated mercurous sulfate reference electrode. The resulting copper deposit on the brass panel exhibited a reflection percentage above 90 % at 550 nm across the full current density range, compared with a burn‑free but matte deposit when the compound was omitted. Galvanostatic chronopotentiometry on a rotating disc electrode (2500 rpm) placed the steady‑state diffusion‑limited current for the leveler at 0.85 A·dm⁻², which aligns with the operating window of printed circuit board through‑hole plating where a thickness uniformity of ≤10 % (centre‑to‑surface ratio) per IPC‑4552 is required. The nitrile group is believed to coordinate to Cu(I)‑chloride complexes at the stagnant diffusion layer adjacent to sharp corners, locally increasing the charge‑transfer resistance and suppressing dendritic growth. Prolonged bath operation (>20 Ah·L⁻¹) leads to the accumulation of cyanoethylpyrrole hydrolysis products that cause a bath‑voltage drift; the breakdown products can be monitored by UV absorbance at 260 nm and the additive must be continuously replenished through a dosing pump set to 0.15 mg·Ah⁻¹·L⁻¹. The plating electrolyte, once spiked with the additive, falls under the general industrial hygiene framework of EU Directive 98/24/EC; however, cyanide is not liberated below 100 °C and the bath pH never exceeds 1.0, so special cyanide‑waste treatment is not triggered. Table 2 compiles the performance metrics that define the additive’s working range.
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| Property | Measured Value | Analytical Method |
|---|---|---|
| Assay (anhydrous basis) | 98.7% | GC-FID, DB-5 column, 30 m × 0.25 mm, split 50:1 |
| Melting range | 54.0–56.5 °C | DSC, 5 K·min⁻¹, nitrogen purge |
| Water (Karl Fischer) | 0.08% | Metrohm 870 KF Titrino plus, hydranal composite 5 |
| Residual acrylonitrile | <50 ppm | Headspace-GC/MS, 80 °C equilibration |
| Pyrrole | <0.2% | GC-FID, as above |
| Non-volatile residue | <0.05% | Gravimetric, 105 °C to constant weight |
| Substrate | Catalyst | Pressure (MPa) | Temp (°C) | Primary Amine Yield (%) | Over‑reduced Species (%) |
|---|---|---|---|---|---|
| N‑(2‑Cyanoethyl)pyrrole | Raney‑Ni 2800 | 4.0 | 80 | 93 | 1.2 |
| N‑Cyanomethylpyrrole | Raney‑Ni 2800 | 4.0 | 80 | 36 | 47 |
| N‑(2‑Cyanoethyl)indole | Pd/C 10% | 0.5 | 25 | 88 | 4.5 |
