| HS Code | 333664 |
| Product Name | Isooctyl Cyanoacetate |
| Chemical Formula | C11H19NO2 |
| Molecular Weight | 197.27 g/mol |
| Cas Number | 13361-34-7 |
| Ec Number | 236-427-8 |
| Synonyms | Cyanoacetic acid isooctyl ester, 2-ethylhexyl cyanoacetate |
| Chemical Class | Cyanoacetate ester |
| Appearance | Colorless to pale yellow liquid |
| Odor | Mild ester-like odor |
| Boiling Point | 256 °C at 760 mmHg |
| Flash Point | >110 °C |
| Density | 0.95 g/cm³ at 20 °C |
| Refractive Index | 1.437 at 20 °C |
| Solubility In Water | Insoluble |
| Solubility In Organic Solvents | Soluble |
| Vapor Pressure | <0.01 mmHg at 20 °C |
| Logp | 2.5 |
| Storage Conditions | Cool, dry, well-ventilated area |
| Hazard | May cause skin and eye irritation |
| Typical Purity | ≥98% |
As an accredited Isooctyl Cyanoacetate factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Isooctyl Cyanoacetate is supplied in 25 kg high-density polyethylene drums with secure closures, suitable for industrial handling and storage. |
| Shipping | Isooctyl cyanoacetate is typically shipped as a liquid in sealed, UN-approved steel or plastic drums, or IBCs. Containers must be labeled and accompanied by SDS and transport documents. Keep cool, dry, and away from oxidizers, acids, bases, heat, and ignition sources. Follow applicable DOT/IMDG/IATA regulations. |
| Storage | Store isooctyl cyanoacetate in a cool, dry, well-ventilated area away from heat, sparks, flames, and direct sunlight. Keep containers tightly closed, upright, and clearly labeled. Protect from moisture and incompatible substances such as strong acids, bases, and oxidizing agents. Use secondary containment and appropriate PPE. Follow local regulations for chemical storage. |
| Shelf Life | Typically 12–24 months when stored sealed, cool, dry, dark, and protected from moisture, acids, bases, and oxidizing agents. |
Manufacture of 2-octyl cyanoacrylate commences with a Knoevenagel condensation between isooctyl cyanoacetate (CAS 13361-34-7) and paraformaldehyde in a glass-lined reactor fitted with a reflux condenser, Dean-Stark trap, and nitrogen inertization. The accepted feed specification for the ester in medical-monomer production is ≥99.0% purity by GC-FID area, moisture <0.1% by Karl Fischer titration, and free cyanoacetic acid <0.05% by acid-base titration; moisture above 0.2% promotes hydrolysis to cyanoacetic acid and 2-ethylhexanol, and the liberated acid suppresses anionic propagation during the later monomer storage phase. Paraformaldehyde with formaldehyde content 91–95% and median particle size <200 µm is charged at a molar ratio of 1.00:1.05 to 1.00:1.15 relative to isooctyl cyanoacetate. Piperidine is metered at 0.1–0.5 wt% of total charge under agitation; the condensation exotherm raises the mass to 70–90 °C, and the temperature is then advanced to 110–130 °C to maintain azeotropic removal of reaction water with toluene or xylene. Reaction completion is determined by cessation of water evolution and by gel permeation chromatography of the precipitated poly(2-octyl cyanoacrylate) oligomer. Production-scale experience indicates that terminating the condensation early produces an oligomer with number-average molecular weight below approximately 2,000 Da; such low-molecular-weight oligomer fraction flashes into the distillate path during subsequent depolymerization and fouls the internal condenser within 4–6 h of continuous operation in a wiped-film evaporator. The oligomer is therefore not isolated as a dry solid but transferred directly to the depolymerization unit.
Thermal depolymerization is conducted in a wiped-film evaporator with internal condenser, heating-medium temperature 180–230 °C, and absolute pressure 1–10 mbar. Sulfur dioxide is injected continuously at 100–500 ppm and phosphorus pentoxide at 0.1–0.3 wt% of oligomer feed to scavenge basic residues and water. Monomer vapor is condensed at −10 to 0 °C into a receiver charged with 50–200 ppm sulfur dioxide and 100–300 ppm butylated hydroxytoluene; the crude is subsequently rectified in a packed column at 1–5 mbar to yield 2-octyl cyanoacrylate of >98.5% GC purity, with residual isooctyl cyanoacetate controlled below 0.5%. Analytical release includes water content <0.1% by Karl Fischer, viscosity 1.5–3.5 mPa·s at 25 °C by Brookfield per ISO 2555:2018, and inhibitor levels by ion chromatography. The finished monomer is supplied to medical device manufacturers under ISO 10993-1 biological evaluation planning; cured film extracts are tested per ISO 10993-5 for cytotoxicity and ISO 10993-10 for skin irritation and delayed-type hypersensitivity. Lap-shear strength of the resulting tissue adhesive is characterized per ASTM F2255-05 (2015); topical skin closure adhesives containing 2-octyl cyanoacrylate are regulated as Class II devices under 21 CFR 878.4010, and extractables testing commonly follows USP <88> Class VI protocols for the cured polymer. End product types include sutureless topical skin adhesives, emergency laceration closure adhesives, and surgical incision closure devices in single-use ampoule applicators. The operational boundary is moisture ingress: exposure of the stabilized monomer to relative humidity above 30% during packaging shortens ambient shelf life from the specified 12 months to less than 60 days by triggering premature anionic polymerization and viscosity increase.
| Stage | Parameter | Documented Range | Analytical Method |
|---|---|---|---|
| Ester feed | Purity | ≥99.0% | GC-FID |
| Ester feed | Moisture | <0.1% | Karl Fischer titration |
| Knoevenagel condensation | Piperidine catalyst | 0.1–0.5 wt% | Gravimetric charge |
| Knoevenagel condensation | Ester:formaldehyde molar ratio | 1.00:1.05–1.15 | Molar charge |
| Depolymerization | Heating-medium temperature | 180–230 °C | RTD probe |
| Depolymerization | Absolute pressure | 1–10 mbar | Capacitance manometer |
| Finished monomer | Sulfur dioxide inhibitor | 50–200 ppm | Ion chromatography |
| Finished monomer | GC purity | >98.5% | GC-FID |
Blending of 2-octyl cyanoacrylate synthesized from isooctyl cyanoacetate into ethyl cyanoacrylate-based instant adhesive formulations is performed in moisture-controlled planetary vacuum mixers with polytetrafluoroethylene-coated vessels and scraped-wall agitators. The octyl monomer is introduced at 5–20 wt% of the liquid monomer charge for general flexibilization of rigid metal-to-plastic bonds; grades targeting elastomer-to-elastomer bonding, where T-peel resistance governs field performance, are compounded at 20–30 wt% octyl monomer. Polymethyl methacrylate thickener with weight-average molecular weight 300,000–600,000 Da is dissolved at 5–10 wt% to raise finished viscosity to 20–1,500 mPa·s depending on dispensing method; fumed silica at 0.1–0.5 wt% is added for thixotropic recovery in vertical-joint assembly. Boron trifluoride diethyl etherate is maintained at 50–150 ppm as anionic inhibitor, and sulfur dioxide at 50–200 ppm as radical and acid scavenger; crown ether or calixarene accelerator is added at 0.1–0.5 wt% only for grades specified for low-energy polyolefin substrates. Vacuum deaeration at 5–20 mbar for 30–60 min removes dissolved oxygen, which otherwise initiates peroxide-mediated side reactions that desensitize the anionic stabilizer package. Filling into aluminum or low-density polyethylene tubes is performed under dry nitrogen with dew point below −40 °C. Production-scale observation on 50 kg batches indicates that residual moisture in the PMMA thickener above 0.2% by Karl Fischer produces viscosity drift exceeding 15% after 90 days at 40 °C accelerated aging, and that compounding above 30 wt% octyl monomer lengthens fixture time on acid-cured rubber substrates beyond 60 s, requiring surface primer application.
Finished flexible grades are qualified against ISO 4587:2003 for lap-shear strength on grit-blasted mild steel and against ASTM D1002-10 for metal-to-metal shear; tensile elongation of cast film specimens is measured per ASTM D638-14, with octyl-containing grades commonly exhibiting elongation at break between 20% and 60% depending on comonomer ratio, while unmodified ethyl cyanoacrylate films measure below 10%. T-peel strength is tested per ASTM D903-98 (2017) on elastomeric coupons; viscosity stability is assessed per ISO 2555:2018 with additional internal protocol exposing sealed tubes to 50 °C for 14 days. End product types include flexible instant adhesives for EPDM gasket bonding, rubber profile splicing, footwear assembly, and vibration-damping component joining. Operational boundary: the octyl comonomer reduces cure speed on acidic surfaces and on substrates conditioned at relative humidity below 20%; pretreatments with organosilane primers or polyamine accelerators are required below that threshold. The octyl monomer must not be combined with amine-functional additives directly in the finished adhesive because amines initiate rapid anionic polymerization and generate exotherm capable of exceeding 80 °C in a 25 g tube within 10 s.
In artificial nail tip application, 2-octyl cyanoacrylate produced from isooctyl cyanoacetate is used as sole monomer or in blends with ethyl cyanoacrylate at ratios from 50:50 to 90:10 by weight. The higher-ester monomer lowers vapor pressure at 23 °C, reducing airborne monomer concentration at the nail perimeter and thereby suppressing white blooming, which forms when volatile cyanoacrylate vapor re-deposits and polymerizes on hydrated keratin. Comparative exotherm measurements on 25–50 µm bond lines in a 10 mm diameter lap joint record lower peak temperature for octyl-containing formulations than for ethyl cyanoacrylate; reported reductions range from 15–30% depending on bond thickness and substrate heat capacity, and the lower propagation rate constant of the 2-octyl ester is the operative mechanism. This reduction is relevant for direct nail plate contact where thermal discomfort is the primary consumer complaint. Polymethyl methacrylate thickener is dissolved at 5–8 wt% in a high-shear disperser at tip speed 10–15 m/s to prevent undissolved particles from clogging 200 µm filling nozzles; fumed silica at 0.1–0.5 wt% provides thixotropy for vertical nail tip positioning. Boron trifluoride diethyl etherate stabilizer is held at 100–300 ppm; quality control monitors Brookfield viscosity per ISO 2555:2018 at 25 °C, water content per Karl Fischer titration, and inhibition time after addition of a standard amine challenge solution.
Compliance for cosmetic nail adhesive finished products follows the matrix below; each production batch is documented under Good Manufacturing Practice per ISO 22716:2007 for cosmetics, and the Cosmetic Product Safety Report is structured per Annex I of EU Regulation 1223/2009.
| Regulation / Standard | Scope | Application to Cyanoacrylate Nail Adhesives |
|---|---|---|
| EU 1223/2009 | Cosmetic product safety | CPSR per Annex I, Article 10 notification, responsible person designation; cyanoacrylate residual monomer monitored in cured nail coating |
| REACH 1907/2006 | Chemical registration | Registration of 2-octyl cyanoacrylate and isooctyl cyanoacetate under Annex VII–X data requirements; Annex XVII restrictions on skin contact where applicable |
| ISO 22716:2007 | GMP for cosmetics | Batch release documentation, raw material traceability, equipment cleaning validation |
| ISO 10993-5 | In vitro cytotoxicity | Cured film extract testing for temporary skin contact where product registration requires biocompatibility evidence |
| ISO 2555:2018 | Brookfield viscosity | Release and stability specification for adhesive flow properties |
The downstream production process for nail adhesive grade monomer is sequential: isooctyl cyanoacetate-derived 2-octyl cyanoacrylate is blended with thickener and stabilizer under vacuum, deaerated at 5–15 mbar for 45 min, and filled under dry nitrogen into 3–10 mL low-density polyethylene dropper bottles with moisture-impermeable seals. End product types include nail tip adhesives, nail wrap resins, and artificial nail coating formulations for professional and retail channels. Operational boundary: the finished nail adhesive must not be stored above 25 °C; storage at 40 °C for 30 days increases viscosity by more than 50% and produces visible gel particles. Published data on the complete dermal absorption profile of cured octyl cyanoacrylate films in the nail application configuration is limited; safety substantiation therefore relies on finished-product patch testing under dermatological supervision and on existing SCCS opinions concerning cyanoacrylate-containing nail products rather than a single harmonized monomer exposure limit.
Equilibrium removal of the 2-ethylhexanol byproduct governs conversion when isooctyl cyanoacetate is transesterified with hydroxyl-functional polyester polyols to produce cyanoacetate-functional resins for Knoevenagel-cured coatings. The polyester polyol is selected with hydroxyl number 100–200 mg KOH/g and acid number <2 mg KOH/g; the ester reactant is charged at 1.0–1.3 equivalents per hydroxyl equivalent to drive the equilibrium forward, and dibutyltin oxide catalyst is used at 0.1–0.3 mol% relative to hydroxyl groups. The reaction is run at 120–160 °C under nitrogen in a glass-lined vessel with vacuum capability; 2-ethylhexanol is removed at 20–50 mbar until the hydroxyl value falls below 5 mg KOH/g, indicating that cyanoacetate end-capping has replaced terminal hydroxyl functionality. The isooctyl ester is selected over methyl or ethyl cyanoacetate in this configuration because the transesterification byproduct, 2-ethylhexanol, has a boiling point of 184–185 °C and is removed without azeotropic solvent, whereas methanol or ethanol removal at the same temperature would require higher reflux ratios and would elevate volatile organic content. Residual isooctyl cyanoacetate is controlled below 0.5 wt% of resin solids by vacuum stripping; higher residuals plasticize the cured network and lower crosslink density. The resulting cyanoacetate-functional polyester is a viscous liquid or low-melting solid with cyanoacetate equivalent weight typically in the range 200–500 g/mol, and it is formulated as a two-component system with an aldehyde-functional urethane oligomer at 1.0:1.0 to 1.2:1.0 aldehyde-to-cyanoacetate molar ratio. 1,4-Diazabicyclo[2.2.2]octane catalyst at 0.5–2.0 wt% on resin solids initiates ambient-temperature Knoevenagel addition; gel time at 23 °C and 50% relative humidity ranges from 15–45 min, and through-cure is reached within 24–72 h. Film hardness is measured per ASTM D4366 pendulum damping, flexibility per ISO 1519 cylindrical bend, adhesion per ISO 2409 cross-cut, and specular gloss per ISO 2813. Production-scale observation on 200 L transesterification batches indicates that incomplete removal of isooctanol above 0.3% in the resin yields surface tack and ISO 2409 classification worse than 2 after 7-day ambient cure, particularly on beech and oak substrates with open grain. Published data for this specific coating configuration in full-scale continuous operation is limited; the processing window described above is derived from batch records and peer-reviewed coating literature rather than a single standardized industrial specification. End product types include ambient-cured wood coatings, two-component plastic refinish clearcoats, and protective sealers for decorative metal hardware.
Veterinary wound closure adhesives based on 2-octyl cyanoacrylate derived from isooctyl cyanoacetate are regulated as devices under FDA Center for Veterinary Medicine jurisdiction when marketed for animal wound approximation. The monomer is specified at >98.5% GC purity with sulfur dioxide inhibitor at 50–200 ppm; D&C Violet No. 2 dye is added at 0.01–0.05 wt% for intraoperative visibility. Formulation viscosity is maintained at 1.5–3.5 mPa·s at 25 °C per ISO 2555:2018 to permit capillary penetration into wound edges from a single-use applicator tip with internal diameter 0.3–0.7 mm. Replacement of n-butyl cyanoacrylate with the octyl ester reduces polymerization exotherm due to slower propagation; published quantitative tissue-temperature data for veterinary-grade octyl formulations is limited, and exotherm characterization must be generated per ISO 10993-1 biological evaluation planning with species-specific justification. The cured octyl ester film is reported to exhibit glass transition temperature between approximately −20 and 0 °C by dynamic mechanical analysis, reducing tissue edge stiffness after skin movement relative to butyl ester films.
Aseptic filling of veterinary applicator tubes is executed in an ISO 5 cleanroom under dry nitrogen; moisture in the headspace must not exceed 0.05% by volume. Terminal sterilization is achieved by gamma irradiation at 25–40 kGy per ISO 11137-1 or ethylene oxide per ISO 11135-1:2014; radiation sterilization is viable only when sulfur dioxide content is maintained above 30 ppm, because lower inhibitor residuals permit radiation-induced anionic polymerization that increases viscosity beyond the device specification. Biological evaluation of the finished device follows ISO 10993-1 endpoints including ISO 10993-5 cytotoxicity, ISO 10993-10 irritation and sensitization, and ISO 10993-11 systemic toxicity where animal-specific justification is required. Lap-shear strength of the cured adhesive on porcine skin substrates is tested per ASTM F2255-05 (2015) adaptations; quantitative acceptance criteria are product- and species-specific, and published data for this specific veterinary configuration is limited, so manufacturers establish release limits through ASTM F2255-05 adaptations rather than relying on a universal minimum. End product types include veterinary surgical incision adhesives, ear margin sealing adhesives after otoplasty, and adjunctive closure adhesives for equine skin lacerations when used with subcutaneous sutures. The product must not be applied to infected wound beds, actively bleeding surfaces, or high-tension skin edges without deep suture support; polymerization is inhibited by proteinaceous exudate and blood, and the instructions for use document reduced bond strength on substrates with high moisture content. This limitation is consistent with ISO 10993-1 biological risk assessment requirements for device-specific indication statements.
Because the monomer must pass through a 0.5–1.0 mm internal-diameter applicator lumen without clogging, 2-octyl cyanoacrylate supplied for tackless hernia mesh fixation is specified at >99.0% GC purity, viscosity 2–10 mPa·s at 25 °C per ISO 2555:2018, and sulfur dioxide inhibitor at 50–200 ppm. Particulate thickeners are excluded from this grade; the low viscosity permits droplet formation of 0.02–0.05 mL per actuation through a laparoscopic applicator with a distal valve mechanism. In the production process, the stabilized monomer is filled into pre-sterilized single-use cartridges under nitrogen in an ISO 5 cleanroom, sealed with moisture-barrier foil, and sterilized by gamma irradiation per ISO 11137-1 at 25–40 kGy. The chemical conversion route from isooctyl cyanoacetate remains the same Knoevenagel–depolymerization sequence used for wound closure monomer, but the mesh fixation grade requires tighter particulate specification: the monomer is filtered through a 0.45 µm polytetrafluoroethylene membrane before cartridge filling, and filter integrity is verified by bubble point per ASTM F838-20. Cartridge filling volume is 0.5–2.0 mL; residual air bubble content above 0.1 mL produces intermittent droplet delivery in the laparoscopic field and is rejected by automated vision inspection.
Fixation performance of the cured adhesive on polypropylene mesh against porcine abdominal wall tissue is characterized by adaptations of ASTM F2255-05 (2015); published comparative data for this specific configuration is limited, and device manufacturers establish product-specific acceptance limits during ISO 10993-1 biological evaluation and 510(k) preclinical testing. Quality system requirements for the finished device follow ISO 13485:2016; the adhesive component is combined with the laparoscopic applicator in a sterile barrier system validated per ISO 11607-1. End product types include tackless mesh fixation kits for laparoscopic inguinal hernia repair, pre-filled adhesive cartridges for reusable applicators, and single-patient disposable applicator sets. Operational boundary: the adhesive must not be used as the sole fixation means for large meshes in high-tension repairs; instructions for use require combining adhesive with absorbable tacks or sutures at the mesh periphery. Polymerization is inhibited by peritoneal fluid; droplet placement must therefore be preceded by brief suction of the fixation site, and the cure time before mesh release is typically 20–40 s at 37 °C and 95% relative humidity, as documented in device-specific technical dossiers rather than a single harmonized standard.
Competitive Isooctyl Cyanoacetate prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615380400285 or mail to sales2@ascent-chem.com.
We will respond to you as soon as possible.
Tel: +8615380400285
Email: sales2@ascent-chem.com
Flexible payment, competitive price, premium service - Inquire now!
Isooctyl cyanoacetate is the branched C8 alkyl ester of cyanoacetic acid, supplied predominantly as the 2-ethylhexyl ester under CAS registry number 13361-34-7. The molecular formula is C11H19NO2, and the molecular weight is 197.27 g mol⁻¹. Industrial material is not governed by a single model designation; manufacturers assign product codes that encode purity, water content, color, residual alcohol, and packaging configuration. The feedstock alcohol is typically 2-ethylhexanol, CAS 104-76-7, produced by oxo synthesis. Because alternative branched octanol isomers may be described as isooctyl alcohol, the exact ester composition should be confirmed by GC-MS or a certified reference standard before use in regulated processes. A representative bulk specification includes purity of not less than 98.0 % by GC area, water content not more than 0.10 % by mass, acid value not more than 0.5 mg KOH g⁻¹, and Pt-Co color not more than 50. The liquid is reported to have a density of 0.95–0.97 g cm⁻³ at 20 °C and a boiling point near 110–115 °C at 0.2 mmHg. These values should be verified against the batch-specific certificate of analysis because the low volatility and high molecular weight distinguish the ester from methyl and ethyl cyanoacetates in both sampling and GC calibration.
Direct esterification is carried out with an acid catalyst such as sulfuric acid or p-toluenesulfonic acid; water is removed as an azeotrope with toluene or cyclohexane. Transesterification of methyl cyanoacetate with 2-ethylhexanol is catalysed by tetraalkyl titanates or tin compounds and liberates methanol. Both routes can leave trace acidic residues; neutralisation and water washing are used to reduce the acid value before final drying. Residual alcohol is stripped by vacuum distillation, and the product is filtered through a 0.5 μm cartridge filter into dried and nitrogen-flushed packaging. For high-purity applications, molecular distillation may be used to reduce color bodies and non-volatile residues.
Isooctyl cyanoacetate participates in Knoevenagel condensation with formaldehyde or paraformaldehyde to form the corresponding alkyl cyanoacrylate oligomer. The branched 2-ethylhexyl chain lowers the water solubility of the ester relative to methyl cyanoacetate; during azeotropic water removal in a glass-lined reactor fitted with a Dean-Stark trap, the organic phase remains less prone to hydrolysis. At the same time, the steric bulk of the 2-ethylhexyl group reduces the rate of the initial addition step compared with ethyl cyanoacetate under identical base loadings. Published kinetic constants for this specific ester are limited, so process development commonly uses a parallel reactor block with internal standard GC monitoring to compare conversion at 85–100 °C and catalyst loadings between 0.5 % and 2.0 % by mass.
In a typical condensation campaign, excess paraformaldehyde is charged at a molar ratio of 1.05:1 to 1.20:1 relative to the ester. Water is removed overhead as a heterogeneous toluene or cyclohexane azeotrope, and the solvent is returned to the reactor through a decanter loop. The reaction endpoint is defined by the disappearance of the cyanoacetate carbonyl band by FTIR or by GC area percent below 1.0 %. Residual formaldehyde is then quenched with aqueous sodium bisulfite before phase separation; the organic layer is washed with deionised water to remove water-soluble catalyst residues. Failure to control the wash pH can lead to ester hydrolysis and an increase in acid value above 0.5 mg KOH g⁻¹. Because the branched ester contains a long nonpolar chain, the organic phase may separate slowly from brine, and production-scale decanters require sufficient residence time to prevent rag-layer carryover.
Gas chromatographic purity is often determined on a 30 m × 0.25 mm 5 % phenyl methylpolysiloxane capillary column with split injection and flame ionisation detection. The high boiling point of the C8 ester requires injection-port temperatures above 250 °C and a column programme ending near 280 °C. Because the ester can thermally degrade in the injection port, cold on-column injection or derivatisation may be used for trace-level impurity quantification. Residual 2-ethylhexanol and cyanoacetic acid are monitored because these species can affect downstream condensation stoichiometry and monomer quality.
In cyanoacrylate adhesive manufacture, isooctyl cyanoacetate is valued primarily as the precursor to 2-octyl cyanoacrylate, which is used in medical skin closure devices and in flexible industrial bonding. The long branched alkyl chain remains present in the polymer backbone and acts as an internal plasticizer. Poly(2-octyl cyanoacrylate) films exhibit lower glass transition temperature, lower modulus, and higher elongation at break than poly(ethyl cyanoacrylate), although the absence of a widely accepted value for the homopolymer Tg in the literature means that measured values should be obtained by differential scanning calorimetry on the specific cured film. Tensile testing of cured adhesive joints may be performed according to ASTM D638-14 or ASTM D1002, but low-modulus films require careful specimen handling to avoid deformation before testing. The precursor itself is not a medical-device material; finished adhesives intended for skin contact are qualified under ISO 10993-1:2018 and may require additional cytotoxicity, sensitization, and irritation testing. Residual monomer, stabilizer, and formaldehyde levels in the finished formulation must be controlled because these species can influence both biocompatibility and adhesion.
For industrial formulations, the ester-derived monomer can be used in flexibilised cyanoacrylate compositions without large additions of external plasticizer. This reduces the risk of plasticizer migration to the bond line and improves retention of peel strength after thermal ageing. However, the lower surface energy of the C8 monomer may reduce adhesion to untreated metals; aluminium, steel, and copper adherends are generally abraded and degreased before bonding. The fixture time on low-energy substrates is longer than for methyl or ethyl cyanoacrylate esters, and open time may be adjusted by using crown ether or calixarene accelerators in the final packaged formulation.
At the monomer stage, 2-octyl cyanoacrylate is often stabilised with sulfur dioxide, hydroquinone, or methanesulfonic acid. The exact stabiliser package influences the cure speed and the shelf life of the finished adhesive. Packaging in high-density polyethylene or aluminium tubes must be validated for moisture vapour transmission, because the monomer polymerises on contact with trace moisture. The precursor isooctyl cyanoacetate does not undergo the same rapid anionic polymerisation, but it is still stored dry to avoid hydrolysis.
Ester hydrolysis is the main non-polymerisation degradation pathway for isooctyl cyanoacetate in storage. Water attack cleaves the ester linkage to form cyanoacetic acid and 2-ethylhexanol; the released acid can accelerate further hydrolysis and raise the acid value of the bulk liquid. Storage tanks and process vessels should therefore be constructed from 316L stainless steel or lined carbon steel, and moisture ingress should be prevented by nitrogen blanketing at low positive pressure. Desiccant breathers on drums and ISO containers are used in production warehouses where relative humidity exceeds 60 %. The product should not be stored with strong bases, primary or secondary amines, or oxidising agents because these materials can initiate condensation, salt formation, or decomposition. Under nitrogen in closed containers, suppliers often assign a shelf life of 12 months from the date of manufacture for material stored at 5–30 °C. Repeated partial drum withdrawals increase headspace moisture and reduce the practical use period; after each transfer, the drum should be reblanketed and resealed immediately.
Before use in a polymerisation campaign, samples should be withdrawn under nitrogen and tested for water content by ISO 760 or ASTM E203, acid value by ASTM D664 or ISO 2114, and purity by GC-FID. If the water content exceeds 0.10 %, drying with molecular sieves is possible, but the sieve type and regeneration temperature must be selected to avoid adsorbing the ester or catalysing aldol-type side reactions. Published data for drying capacity and breakthrough time for this specific ester are limited; pilot-scale drying tests are therefore required before a bulk dehydration step is introduced.
If drums are received with damaged seals or if the nitrogen blanket has been lost, incoming QC should include headspace moisture measurement and visual inspection for haze or phase separation. Haze in a normally clear liquid may indicate free water, partial hydrolysis, or polymerised contaminants. Centrifugation or filtration through a 0.45 μm membrane can remove particulate contamination, but filtration should not be used as a substitute for proper drying when the water content exceeds specification.
Quality-control plans for incoming isooctyl cyanoacetate commonly include the following batch-control parameters. The values shown are representative technical data sheet limits and may vary by supplier; only the certificate of analysis for the batch being inspected should be used for release decisions.
| Parameter | Representative limit | Test method |
|---|---|---|
| Purity by GC | ≥ 98.0 % area | In-house GC-FID method |
| Water content | ≤ 0.10 % by mass | ISO 760 or ASTM E203 |
| Acid value | ≤ 0.5 mg KOH g⁻¹ | ASTM D664 or ISO 2114 |
| Color, Pt-Co | ≤ 50 | ASTM D1209 |
| Density at 20 °C | 0.95–0.97 g cm⁻³ | ASTM D4052 or ISO 12185 |
| Boiling point at reduced pressure | 110–115 °C at 0.2 mmHg | Supplier distillation curve |
Replacing ethyl cyanoacetate with isooctyl cyanoacetate in a Knoevenagel condensation and subsequent thermal cracking process changes the thermal profile of the synthesis. The boiling point of isooctyl cyanoacetate at atmospheric pressure is higher than that of ethyl cyanoacetate; vacuum is therefore required for both the removal of unreacted ester and the distillation of the intermediate oligomer. In production-scale wiped-film or short-path evaporators, the increase in molecular weight and viscosity of the C8 oligomer can require higher hot-oil temperatures or lower feed rates than ethyl-based operations. The lower vapour pressure of the resulting 2-octyl cyanoacrylate reduces atmospheric emissions during monomer collection but also makes the final distillate more sensitive to thermal stabilizer depletion. Sulfur dioxide or methanesulfonic acid stabilizers are typically added to the receiving vessel at concentrations specified by the stabilizer supplier and verified by titration or ion chromatography.
The polymer derived from the isooctyl chain has a lower glass transition temperature and greater chain flexibility than poly(ethyl cyanoacrylate). This difference is most relevant in applications where cyclic joint movement or low-temperature service is expected. The internal plasticization can be quantified by dynamic mechanical analysis; ethylene-based cyanoacrylate homopolymers generally show a higher storage modulus and earlier brittle failure, while the octyl variant displays a lower storage modulus and a broader tan δ peak. However, published comparative DMA data for these exact homopolymer films are limited, and specimen preparation must be standardised because residual monomer and moisture content affect the measured relaxation behaviour.
In adhesive formulation, the isooctyl-derived monomer generally exhibits slower fixture times on aluminium and steel than methyl or ethyl cyanoacrylate formulations at comparable humidity, because the longer alkyl chain reduces the electrophilicity of the β-carbon and may sterically hinder the anionic propagation step. The open time can be extended further on low-surface-energy plastics such as polypropylene and polytetrafluoroethylene, which require primer or surface treatment before bonding. Adhesion tests should follow ASTM D1002 or DIN EN 1465 for lap shear and ISO 11343 for impact peel where relevant, but end users must establish acceptable performance windows because fixture time and bond strength are dependent on temperature, relative humidity, and substrate preparation.
Comparative data for methyl, ethyl, and isooctyl cyanoacetate are often summarised in supplier technical bulletins, but the exact values for vapor pressure, water solubility, and partition coefficient should be taken from the safety data sheet and from measured batch data. The branched C8 ester shows lower water solubility and higher log P than the short-chain esters, which alters environmental partitioning and ventilation requirements. In process design, the lower volatility reduces the need for high-flow vapour extraction during reactor charging, but the higher boiling point increases the energy demand for solvent recovery and final stripping.
Chemical inventory status must be confirmed by the receiving site. In the European Union, manufacturers and importers are required to ensure that the substance is registered under REACH for the relevant tonnage band and to provide an extended safety data sheet with exposure scenarios for industrial handling. In the United States, the material should be verified against the TSCA inventory. For medical-device applications, the precursor is not an approved medical material; the finished monomer and device must be assessed under ISO 10993-1:2018, including the evaluation of leachables and degradation products. Biocompatibility testing of the precursor alone is not sufficient to qualify an adhesive. Residual solvent, cyanoacetate, formaldehyde, and stabilizer levels should be controlled by validated GC and HPLC methods and reported on the certificate of analysis when the material is intended for high-purity applications.
Product quality agreements may also require compliance with REACH Annex II safety data sheet formatting and with national transportation classifications for combustible liquids. Because cyanoacetate esters can generate hydrogen cyanide during combustion, fire-fighting procedures should follow the supplier’s safety data sheet, and the product should be kept away from open flames and high-temperature equipment. No special storage classification under the UN Model Regulations may apply for the pure ester, but the supplier SDS should be checked for specific transport and environmental labels.
