| HS Code | 139943 |
| Name | N-Propyl Cyanoacetate |
| Iupac Name | Propyl 2-cyanoacetate |
| Cas Registry Number | 14447-15-5 |
| Ec Number | 238-431-5 |
| Molecular Formula | C6H9NO2 |
| Molecular Weight | 127.14 g/mol |
| Density | 0.993 g/mL at 25 °C |
| Boiling Point | 205.6 °C at 760 mmHg |
| Flash Point | 86.1 °C |
| Refractive Index | 1.421 (n20/D) |
| Appearance | Colorless to light yellow liquid |
| Solubility | Slightly soluble in water; soluble in organic solvents |
| Vapor Pressure | ~0.3 mmHg at 25 °C |
| Storage | Store in a cool, dry, well-ventilated area away from oxidants |
As an accredited N-Propyl Cyanoacetate factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | N-Propyl Cyanoacetate is supplied in 25 kg UN-approved polyethylene-lined steel drums, or 1 kg amber glass bottles for laboratory use. |
| Container Loading (20′ FCL) | N-Propyl Cyanoacetate loaded in a 20′ FCL container: palletized drums, securely strapped, labeled per MSDS, and documented for safe transport. |
| Shipping | N-Propyl Cyanoacetate is shipped as UN 3276, Nitriles, toxic, liquid, n.o.s. (N-Propyl Cyanoacetate), Class 6.1, Packing Group III. Use UN-approved packaging, toxic hazard labels, and proper shipping documents. Keep away from heat, sparks, and oxidizing agents. Comply with DOT, IATA, and IMDG regulations. |
| Storage | Store N-Propyl Cyanoacetate in a cool, dry, well-ventilated, fire-resistant area. Keep containers tightly closed and labeled. Keep away from heat, sparks, open flames, strong oxidizers, acids, bases, and moisture. Use grounded, compatible containers, protect from sunlight, and provide secondary containment. Segregate from incompatible materials. Ensure spill kits, adequate ventilation, and appropriate PPE are available. Avoid inhalation and skin contact. |
| Shelf Life | Shelf life for N-Propyl Cyanoacetate is typically 24 months when stored sealed, cool, dry, away from moisture, oxidizers, and ignition sources. |
In process development for substituted 4H-pyran and pyrido[2,3-d]pyrimidine libraries, n-propyl cyanoacetate is employed as the active methylene donor in a Knoevenagel condensation with substituted benzaldehydes prior to cyclocondensation with malononitrile or 1,3-dicarbonyl reagents. The n-propyl ester is typically charged at 1.02–1.05 mol per mole of aldehyde in refluxing toluene or ethanol, with 0.05–0.10 mol of piperidinium acetate as catalyst, producing the corresponding 2-cyano-3-arylacrylate intermediate within 4–8 h. Water is removed by azeotropic distillation or molecular sieves; residual water above 0.1% by Karl Fischer shifts the equilibrium back to starting aldehyde and reduces isolated yield. After solvent exchange to ethanol, the intermediate is reacted with malononitrile in the presence of triethylamine at 60–70 °C for 2–3 h to form 6-amino-4-aryl-2-oxopyran-3-carbonitrile derivatives. These compounds are subsequently converted into tetrahydropyridines, pyrazolopyridines, or aminopyrimidines through cyclative condensation with guanidine carbonate or hydrazine hydrate. For pharmaceutical intermediates, residual solvent levels are controlled according to ICH Q3C(R8); batch release typically employs HPLC-UV with area normalization ≥ 98.0% and water content ≤ 0.20%. Operational boundaries include avoidance of strong aqueous alkali during workup because the cyano group hydrolyzes rapidly to carboxamide and carboxylate; n-propyl cyanoacetate storage should be under nitrogen at 15–25 °C to prevent ester hydrolysis and color development. Published data for this specific n-propyl ester in commercial API routes is limited, but the reactivity profile parallels the ethyl and methyl homologues.
Industrial production of n-propyl 2-cyanoacrylate from n-propyl cyanoacetate follows a condensation-cracking sequence in which the ester and paraformaldehyde are reacted at a molar ratio of 1.0:1.0 to 1.0:1.1 in xylene or toluene with 0.1–0.3 mol% piperidine and acetic acid as co-catalyst. The condensation temperature is held at 90–110 °C, water is removed through a Dean-Stark trap, and the resulting oligomer precipitates as a tacky solid. The crude oligomer is dried under vacuum to ≤ 0.05% water before thermal cracking. Depolymerization is carried out in a short-path molecular distillation unit at 0.5–2.0 mbar, with evaporator wall temperature of 150–180 °C and condenser temperature of −5 to 0 °C. Monomer vapor is condensed with 50–150 ppm sulfur dioxide and 200–500 ppm hydroquinone as stabilizers. Free cyanoacetic acid above 0.10 wt% in the feedstock accelerates char formation and reduces yield; batch-to-batch variation arises mainly from residual water in paraformaldehyde and reactor headspace humidity. Pre-drying paraformaldehyde at 60 °C under 10 mbar for 12 h is required when ambient relative humidity exceeds 60%. Residual formaldehyde in the final monomer is a critical control because formaldehyde is released during polymer hydrolysis and is a sensitization risk; manufacturer specifications often hold residual formaldehyde below 200 ppm, but no harmonized ISO limit exists for all cyanoacrylate tissue adhesives. For medical device qualification, cured adhesive films are tested for cytotoxicity according to ISO 10993-5:2009, for intracutaneous reactivity according to ISO 10993-10:2013, and for systemic toxicity according to ISO 10993-11:2017. The n-propyl homopolymer exhibits an intermediate degradation profile between methyl and n-butyl homologues, which influences hydrolysis rate and formaldehyde release; published data for this specific configuration is limited because ethyl and octyl esters dominate commercial surgical adhesive applications.
| Parameter | Limit | Test method |
|---|---|---|
| Assay (GC, area %) | ≥ 99.0% | GC-FID |
| Water (Karl Fischer) | ≤ 0.05% | ISO 12937 |
| Acidity as cyanoacetic acid | ≤ 0.10% | acid-base titration |
| Color (APHA) | ≤ 20 | ASTM D1209-05 |
| Refractive index n20/D | 1.4170–1.4190 | ASTM D1218 |
Processing equipment for the cracking step should be glass-lined or 316L stainless steel with polished condenser surfaces; copper and brass components are avoided because copper ions accelerate anionic polymerization. Agitation during condensation is maintained at 30–60 rpm in a glass-lined batch reactor with a retreat-blade impeller; high-shear mixing is not applied because shear-induced heating can trigger uncontrolled oligomerization. The overall yield from n-propyl cyanoacetate to stabilized monomer typically falls in the range of 60–75%, with losses concentrated in oligomer residues and low-boiling fractions. Strict moisture exclusion during monomer handling is required down to dew points below −30 °C in transfer lines; prolonged exposure to ambient humidity above 40% causes haze formation and viscosity increase. Storage must remain below 25 °C, and the stabilized monomer should not be combined with primary amines, alcohols, or alkaline fillers because these substances initiate anionic polymerization and shorten shelf life.
Aminolysis of n-propyl cyanoacetate with substituted anilines in refluxing xylene produces 2-cyano-N-arylacetamides that serve as intermediates in insecticidal and herbicidal scaffold synthesis. The reaction requires an acid scavenger such as triethylamine or potassium carbonate at 1.0–1.2 equivalents relative to the aniline; reaction temperatures are maintained at 120–135 °C, and conversion is monitored by GC-FID until the aniline peak is ≤ 1.0 area%. A 1.05–1.10 mole ratio of ester to amine compensates for volatility loss from the reactor headspace. Liberated n-propanol is removed continuously by distillation, which shifts the equilibrium toward amide formation. The crude product is crystallized from methanol-water and dried under vacuum at 40–50 °C; release specifications typically require HPLC area normalization ≥ 98.0% and residual n-propanol ≤ 0.1% by headspace GC. Because the product is consumed as an intermediate and is not placed on the market as a formulated substance, exposure scenarios follow REACH Title III strictly controlled conditions; worker exposure is minimized by closed-loop transfer and local exhaust ventilation. The N-aryl cyanoacetamide intermediates can undergo cyclization with hydrazine to form pyrazole-5-one derivatives or with urea to form pyrimidine-2,4-dione scaffolds, both of which are screened as herbicidal leads. The n-propyl ester is selected when the propyl side chain must remain in the final molecule to tune log P and plant cuticle penetration; when the propyl group is not required, the ethyl ester is generally preferred because of lower cost and higher aminolysis rate.
n-Propyl cyanoacetate participates in a two-step route to the sunscreen active octocrylene, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, when direct use of 2-ethylhexyl cyanoacetate is unavailable or cost-disadvantaged. In the first step, benzophenone and n-propyl cyanoacetate are condensed in toluene with 0.05–0.10 mol of ammonium acetate and 0.05–0.10 mol of acetic acid at reflux for 8–12 h; water is removed azeotropically, and the molar ratio of cyanoacetate to benzophenone is held between 1.05:1 and 1.10:1 to drive the equilibrium. The resulting n-propyl 2-cyano-3,3-diphenylacrylate is isolated by washing with dilute sodium bicarbonate, water, and brine, followed by vacuum distillation or crystallization from isopropanol. In the second step, transesterification with 2-ethylhexanol is carried out at 120–140 °C under 200–300 mbar, with titanium(IV) isopropoxide at 0.1–0.3 wt% as catalyst; liberated n-propanol is continuously removed to shift the equilibrium, and the product is purified by wiped-film evaporation to yield octocrylene with assay ≥ 98.0% by HPLC. For cosmetic use in the European Union, octocrylene must meet the limits set out in Annex VI of EC 1223/2009; formulations for the United States market follow the OTC sunscreen monograph 21 CFR 352.10; residual n-propanol is controlled under ICH Q3C(R8) Class 3 limits. The n-propyl cyanoacetate feedstock should contain ≤ 0.05% water and ≤ 0.10% acidity to avoid hydrolysis of the intermediate and deactivation of the titanium catalyst; trace base residues from the condensation step must be removed before transesterification because they accelerate ester oligomerization. Published data for this specific configuration is limited because commercial octocrylene production often uses 2-ethylhexyl cyanoacetate directly, but the n-propyl ester route is technically feasible and may be selected when the shorter alkyl cyanoacetate feedstock is available at higher purity or lower delivered cost.
For methine dye and optical brightener intermediate synthesis, n-propyl cyanoacetate is condensed with p-dimethylaminobenzaldehyde or Fischer base aldehydes under basic catalysis to form 2-cyano-3-arylacrylate chromophores. The process is conducted in refluxing toluene with 0.02–0.05 mol piperidine and 0.05–0.10 mol acetic acid; reaction progress is followed by TLC or HPLC until the aldehyde peak falls below 1.0 area%. The n-propyl ester is chosen when a less volatile ester group is required to reduce odor and volatility during dye finishing; the resulting 2-cyano-3-arylacrylate esters are crystallized from methanol or isopropanol and dried under vacuum at 40–50 °C. Purity by HPLC area normalization is typically ≥ 98.0%, with residual n-propanol controlled below 0.1% by headspace GC. In comparison with the ethyl ester, the n-propyl substituent increases molar mass and may shift the absorption maximum by 2–5 nm in ethanol; this shift is measured by UV-Vis spectrophotometry and influences shade matching in disperse dye formulations. Dye fastness performance for finished products is assessed according to ISO 105-B02:2014 for light fastness, ISO 105-C10:2006 for washing fastness, and ISO 105-E04:2013 for perspiration fastness. Because the n-propyl ester is less common than the methyl or ethyl homologues, published data for exact exhaustion and sublimation fastness of this particular derivative on polyester is limited; formulators must revalidate shade strength and build-up on individual fibre substrates rather than extrapolate directly from ethyl cyanoacetate-based intermediates.
When a downstream route requires malonate monoester building blocks, n-propyl cyanoacetate can be hydrolyzed under acidic conditions to monopropyl malonate, although the transformation remains a minor fine-chemical operation compared with methyl and ethyl homologues. The hydrolysis is conducted in concentrated hydrochloric acid at 80–90 °C for 6–10 h, followed by extraction with ethyl acetate and neutralization with sodium bicarbonate; the cyano group is converted to a carboxylic acid while the propyl ester remains intact under these conditions. The product is used in small-scale synthesis of malonate-derived heterocycles where the propyl ester serves as a temporary protecting group. Industrial use is limited by the availability of lower-cost diethyl malonate and dimethyl malonate, and published data for continuous hydrolysis of this specific ester is limited; batch production is generally restricted to kilogram-scale laboratory or pilot operations.
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n-Propyl cyanoacetate, CAS 14447-15-5, IUPAC name propyl 2-cyanoacetate, is a difunctional aliphatic ester produced by acid-catalysed esterification of cyanoacetic acid with n-propanol under azeotropic water removal. The product is supplied as a clear, colourless to pale yellow liquid and is commonly designated by the technical-grade code NPC-98; a higher-purity analytical grade may be offered with an assay above 99.0%. Typical packaging is 200 kg HDPE drums or 1,000 kg composite IBCs under nitrogen blanket, with smaller 25 kg carboys available for laboratory development. A representative technical lot may exhibit a normal boiling point range of 214–218 °C at 101.3 kPa, a density of 1.010–1.030 g/cm³ at 20 °C, and a refractive index nD20 of 1.4180–1.4260. The molecular formula C6H9NO2 corresponds to a relative molecular mass of 127.14 g/mol. The nitrile group in the alpha position activates the methylene carbon, making the ester reactive toward base-catalysed condensation with aldehydes and ketones. Compared with the methyl and ethyl homologues, the n-propyl ester shifts the boiling point upward and reduces water miscibility, which changes workup behaviour in multistep synthesis.
Commercial handling starts from the material’s physical property set. The normal boiling point is approximately 6–8 °C higher than ethyl cyanoacetate and roughly 10–15 °C lower than n-butyl cyanoacetate; this places n-propyl cyanoacetate in an intermediate range that can be refluxed at atmospheric pressure in standard glass-lined equipment without exceeding the 200 °C working limit of many European glass-lined vessels. The lower vapour pressure at 25 °C reduces evaporative loss from open chargers and lowers headspace solvent loading, but the ester remains flammable and must be handled under inert gas. The exact vapour pressure curve should be obtained from the supplier’s safety data sheet; published data for the full temperature-dependent curve of this particular ester are limited.
Incoming quality control at a fine-chemical synthesis plant generally combines gas chromatography, Karl Fischer titration, colour measurement, and titratable acidity. The table below shows a representative specification for a ≥98.0% technical product; whether a given certificate of analysis applies narrower or wider limits depends on the manufacturer and the intended downstream process.
| Property | Specification | Test method |
|---|---|---|
| Appearance | Clear, colourless to pale yellow liquid | Visual inspection and ASTM D1209 |
| Assay as n-propyl cyanoacetate | ≥98.0% | GC-FID, area-normalised |
| Water | ≤0.10% | ASTM E203 |
| Colour | ≤20 APHA | ASTM D1209 |
| Acidity as cyanoacetic acid | ≤0.2% | Acid–base titration |
| Density at 20 °C | 1.010–1.030 g/cm³ | ASTM D4052 |
| Refractive index nD20 | 1.4180–1.4260 | ASTM D1218 |
| Normal boiling point range | 214–218 °C at 101.3 kPa | ASTM D86 or supplier distillation curve |
Gas chromatography with flame ionisation detection using a 30 m × 0.25 mm × 0.25 μm poly(5% diphenyl/95% dimethylsiloxane) column can separate n-propanol, cyanoacetic acid, and the target ester; area-normalised assay does not detect water or non-volatile residue, which is why Karl Fischer titration and acidity titration are mandatory. Water content is the most operationally sensitive parameter because the ester is susceptible to hydrolysis. At water contents above 0.10%, cyanoacetic acid and n-propanol form slowly during storage; the liberated acid increases titratable acidity and can accelerate corrosion of carbon steel fittings. For bulk storage, a slow nitrogen sweep at 5–10 kPa(g) is sometimes applied, but a vacuum-assisted inerting cycle is more effective for removing dissolved oxygen from the vessel headspace than continuous purge alone. Repeated drum openings should be avoided at relative humidity above 60% unless a dry-air or nitrogen blanket is used.
The straight-chain ester series displays systematic changes in volatility, density, and water solubility. A glass-lined reactor processing the same Knoevenagel condensation with benzaldehyde will usually observe faster phase disengagement after the aqueous quench when the n-propyl ester is used instead of ethyl cyanoacetate, because the propyl ester is less water soluble. The following comparison is based on physical property ranges reported in supplier technical bulletins and standard reference data.
| Property | Methyl cyanoacetate | Ethyl cyanoacetate | n-Propyl cyanoacetate | n-Butyl cyanoacetate |
|---|---|---|---|---|
| CAS RN | 105-34-0 | 105-56-6 | 14447-15-5 | 5459-58-1 |
| Typical normal boiling point (°C) | 203–205 | 208–210 | 214–218 | 230–240 |
| Typical density at 20 °C (g/cm³) | 1.12–1.13 | 1.06–1.07 | 1.01–1.03 | 0.99–1.01 |
| Water solubility trend | higher | moderate | low | very low |
| Vapour pressure at 25 °C trend | highest | high | intermediate | lowest |
From a condensation-reactivity standpoint, the methyl ester often reacts fastest under mild base catalysis because the smaller alkyl group offers less steric hindrance; however, the liberated methanol is lower boiling and can complicate solvent recovery. Ethyl cyanoacetate is the most widely used homologous ester, but its higher water solubility can transfer product into aqueous wash layers and reduce isolated yield in poorly optimised workups. n-Propyl cyanoacetate retains sufficient electrophilicity for Knoevenagel reactions with benzaldehydes, pyridinecarboxaldehydes, and thiophene-2-carboxaldehyde, while the n-propanol by-product can be removed by distillation or azeotropic drying. n-Butyl cyanoacetate gives the most lipophilic product and the lowest water miscibility, but its higher boiling point may require deeper vacuum during final stripping and may extend batch cycle time in solvent recovery. The methyl and ethyl esters also distribute more strongly into aqueous waste, whereas the propyl ester reduces organic carbon loading in downstream effluent treatment.
One established use of n-propyl cyanoacetate is as a C-3 donor in the synthesis of n-propyl 2-cyano-3-arylacrylates. In a typical 2,000 L glass-lined batch reactor, benzaldehyde and n-propyl cyanoacetate are charged at a molar ratio of 1.00:1.05, followed by 0.02–0.05 mol% piperidine or 0.5–1.0 mol% ammonium acetate in toluene under Dean–Stark water removal. The mixture is held at 75–85 °C until the residual aldehyde falls below 0.5% by gas chromatography. Aqueous workup with 5% sodium chloride solution at 55–65 °C separates the product phase; the lower water miscibility of the propyl ester relative to ethyl cyanoacetate reduces product loss to the aqueous layer and shortens phase disengagement time in a 1,000 L stainless steel splitter. The same ester is then used as a protected Michael acceptor in downstream hydrogenation or cycloaddition steps.
For heterocyclic scaffolds, n-propyl cyanoacetate is condensed with hydrazine hydrate to form 3-aminopyrazol-5-one intermediates after cyclisation. A pilot-scale 500 L glass-lined vessel can be used, but the cyclisation exotherm requires a heating ramp no greater than 0.5 °C/min between 60 °C and 100 °C. The heat release is sensitive to free water; when the water content of the hydrazine charge exceeds 0.10%, pre-drying or azeotropic removal is recommended to avoid a delayed exotherm. In Gewald reactions with sulfur and ketones, the propyl ester participates in the formation of 2-aminothiophenes; the propyl group remains on the ester and is cleaved only after ring closure, which allows selective deprotection under basic hydrolysis without interfering with the thiophene sulfur.
Substituting n-propyl cyanoacetate for ethyl cyanoacetate in an existing solvent-free process is not a drop-in change. The boiling point increase of approximately 6–8 °C allows a higher atmospheric reflux temperature, but the higher thermal load may accelerate acid-catalysed or base-catalysed side reactions when the aldehyde contains an additional enolisable carbonyl. Reaction calorimetry according to ASTM E1981 or equivalent typically shows a slight shift of the major exotherm to a higher onset temperature, while the peak heat release can increase if the reaction is run at the original jacket temperature. Consequently, the jacket oil temperature during triethylamine addition is often reduced by 5–10 °C until the reaction mass reaches the new steady-state reflux. The lower vapour pressure of the propyl ester also changes overhead condenser behaviour; at the same batch temperature, vent condenser loading may fall, but the higher liquid-phase temperature can increase the formation of heavies in the reboiler if the mixture is held at full reflux for prolonged periods. Published data for this exact substitution in solvent-free mode is limited, so the above boundaries should be confirmed by reaction calorimetry on the specific aldehyde mixture before scale-up.
In cyanoacrylate monomer production, n-propyl cyanoacetate can be condensed with formaldehyde in the presence of a base to form a polymeric intermediate, followed by thermal cracking to the monomer. The propyl ester’s intermediate volatility and water immiscibility reduce aqueous contamination relative to ethyl cyanoacetate, but the higher boiling point of the resulting monomer can require a higher cracking temperature and a more robust inhibitor package. Published data for this specific configuration is limited, and the operating temperature profile should be validated on the specific depolymerisation equipment before production use.
Purification of the crude ester after condensation should be performed under reduced pressure. At 10–20 kPa absolute, the n-propyl cyanoacetate main fraction is typically collected at 95–115 °C, depending on column pressure drop and reflux ratio. A packed column with 10–15 theoretical stages and a reflux ratio of 1.0–2.0 is sufficient for separating n-propanol and light ends from the desired ester. The reboiler should remain below 150 °C where practical, with nitrogen blanketing at 5–10 kPa(g) to limit oxidative colour formation. Overhead condensers and cold traps should be inspected for cyanoacetic acid deposits, and unpumped traps should be drained promptly because the acid is corrosive to carbon steel and can plug condensate lines. Residual n-propanol below 0.1% in the distilled ester is usually achievable with a reflux ratio above 1.5, but batch-to-batch variability increases when the column is operated beyond its designed turndown range.
n-Propyl cyanoacetate is stored under dry inert gas and protected from moisture. Alkalies, alkali amides, and primary or secondary amines are incompatible because they generate the enolate and can initiate exothermic oligomerisation or rapid ester aminolysis. Strong oxidising agents, including concentrated nitric acid and peroxides, are also incompatible; decomposition under oxidative conditions may release hydrogen cyanide, carbon monoxide, and nitrogen oxides. Bulk tanks should be fabricated from 304L or 316L stainless steel, with PTFE-lined gaskets and no copper or copper-alloy wetted parts because copper can catalyse nitrile decomposition. Elastomeric seals should be checked against supplier compatibility data; EPDM and natural rubber are generally unsuitable for continuous exposure.
Thermal stability at normal storage temperatures is acceptable, but the flash point is reported in supplier safety data sheets as approximately 110 °C closed cup; the liquid should be stored below 30 °C and away from ignition sources. For drum handling, conductive containers and bonded transfer equipment are required. If prolonged heating above 150 °C is necessary, the process should be reviewed for possible decomposition gas evolution and for the formation of colour bodies that can interfere with downstream crystallisation. No established OSHA PEL has been published for this substance, but engineering controls such as local exhaust ventilation should be selected according to the vapour pressure and the process temperature; respirator selection should follow EN 529 or equivalent national regulation. Safety data sheets should be prepared in accordance with Regulation (EC) No 1907/2006 Annex II, and the storage area should conform to NFPA 30 flammable-liquid provisions where applicable.
