1-Cyclohexyl-Pyrrole-2,5-Dione

Product Name 1-Cyclohexyl-Pyrrole-2,5-Dione
Alias N-Cyclohexylmaleimide
Einecs 277-143-2
Mininmum Order 25g
Factory Site West Ujimqin Banner, Xilingol League, Inner Mongolia, China
Price Inquiry sales9@bouling-chem.com
Manufacturer Bouling Chemical Co., Limited
CONTACT NOW

In terms of specification, 1-Cyclohexyl-Pyrrole-2,5-Dione is supplied with ≥98% purity (GC) and melting point 87–89 °C, making it suitable for applications in organic synthesis and polymer chemistry.

Specifications

HS Code	803013
Name	1-Cyclohexyl-Pyrrole-2,5-Dione
Molecular Formula	C10H13NO2
Molecular Weight	179.216 g/mol
Appearance	Solid (Typical)
Boiling Point	Approx. 337.9 °C at 760 mmHg
Melting Point	112 - 116 °C
Density	1.185 g/cm³
Solubility In Water	Insoluble
Flash Point	158.2 °C

As an accredited 1-Cyclohexyl-Pyrrole-2,5-Dione factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.

Packing & Storage

Packing	100g of 1 - Cyclohexyl - Pyrrole - 2,5 - Dione packaged in a sealed, labeled container.
Shipping	1 - Cyclohexyl - Pyrrole - 2,5 - Dione is shipped in accordance with chemical transportation regulations. It's carefully packaged to prevent leakage, transported by approved carriers, ensuring safety during transit to its destination.
Storage	1 - Cyclohexyl - Pyrrole - 2,5 - Dione should be stored in a cool, dry place away from heat sources and direct sunlight. Keep it in a well - sealed container to prevent moisture absorption and contact with air, which could potentially lead to degradation. Store it separately from incompatible substances, like strong oxidizing agents or bases, in a designated chemical storage area following safety regulations.

Application of 1-Cyclohexyl-Pyrrole-2,5-Dione

How Does Cyclohexyl Maleimide Content Influence the Transparency-Heat Resistance Trade-off in PMMA Continuous Cast Sheets?

In continuous cast poly(methyl methacrylate) production for optical-grade sheets requiring a service temperature above 100°C without compromising visible light transmission, N-cyclohexylpyrrole-2,5-dione is copolymerized into the methyl methacrylate backbone at the monomer preparation stage. The specific refractive index increment of CHMI (n_D ≈ 1.51) remains sufficiently close to that of PMMA (n_D 1.489–1.493) such that haze values measured per ASTM D1003 remain below 2.0% at incorporation ratios up to 15 wt% based on total monomer charge. Above 18 wt% CHMI, localized heterogeneities in segmental density during bulk polymerization induce microphase-separated domains 50–200 nm in diameter, leading to a non-linear increase in wide-angle scattering; the practical limit for transparent applications is therefore established at 15 ± 2 wt%. The polymerization is conducted as a two-stage isothermal cast process: pre-polymerization in a jacketed stirred tank at 80–85°C under nitrogen to 20–25% conversion, followed by in-mold curing in a water bath with a temperature ramp from 45°C to 115°C over 8 hours to minimize residual monomer and internal stress. Finished sheets must conform to DIN EN ISO 12017 (formerly DIN 7745) for dimensional tolerance and to ISO 1133-1:2022 for melt volume-flow rate verification before thermoforming. End products include LED flat-panel diffuser plates, automotive rear-light inner lenses, and aircraft cabin window transparencies where compliance with FAR 25.853 flammability is mandatory. A processing audit on a dedicated cast-sheet line revealed that when CHMI exceeds 15 wt%, the exotherm peak during curing shifts upward by 12°C, requiring active chill-water circulation in the mold frames to prevent bubble formation; operators must also extend the annealing cycle by 4 hours to reduce optical retardation below 20 nm as measured at 589 nm.In twin-screw compounding of glass-fiber-reinforced polypropylene/polyamide 6 blends destined for under-hood automotive components, anhydride-free compatibilization is achieved through melt grafting of N-cyclohexylpyrrole-2,5-dione directly onto the PP backbone. The reactive extrusion setup employs a co-rotating twin-screw extruder with an L/D ratio of 44:1, configured with a side-feeder for polyamide and a liquid-injection port at barrel zone 6 for the CHMI monomer premixed with 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane initiator. The radical grafting is performed at a screw speed of 300–400 rpm with a flat barrel temperature profile of 185–200°C; the initiator’s half-life at 195°C is approximately 0.2 minutes, ensuring over 99% decomposition within two screw diameters yet restricting the residence time available for monomer diffusion. CHMI addition rates are maintained at 1.5–3.0 phr relative to PP, with grafting efficiencies determined by FTIR peak area ratios (C=O stretching at 1705 cm⁻¹ vs. PP internal standard) falling to 48–55% at the upper limit due to competing homopolymerization and evaporative loss at the vent port. Torque monitoring indicates that at 3.0 phr CHMI, a 12–15% increase in specific mechanical energy input is observed relative to unmodified PP, attributable to melt viscosity amplification from long-chain branching side reactions. The grafted PP-g-CHMI copolymer reduces the dispersed PA6 domain size in the blend to 0.8–1.2 µm, as verified by scanning electron microscopy of cryofractured surfaces etched with formic acid, enabling a notched Izod impact value at -30°C (ASTM D256) of 8.5 kJ/m² versus 3.2 kJ/m² for the uncompatibilized control. Compliance for engine-cover applications requires passing UL 94 V-2 at 1.6 mm and resistance to hot engine oil per ISO 1817 for 168 hours at 100°C. Terminal components include cooling fan shrouds, air-intake manifolds, and battery trays where a continuous use temperature of 120°C is specified.

Reaction Extrusion Parameters for Anhydride-Free Compatibilization of PP/PA6 Alloys

When regulatory migration limits require a non-phthalate heat modifier for styrene-acrylonitrile copolymers in microwave-safe food containers, N-cyclohexylpyrrole-2,5-dione is introduced as a termonomer in the continuous mass polymerization of SAN intended for articles repeatedly contacting aqueous, acidic, or fatty food simulants. The copolymer composition is controlled at 8–20 wt% CHMI, 65–74 wt% styrene, and 18–22 wt% acrylonitrile, with the CHMI level dictating the Vicat softening temperature (ISO 306, method B50) from 108°C to 132°C. The polymerization is performed in a series of stirred-tank reactors followed by devolatilization extrusion at 220–240°C and 2–5 mbar absolute pressure to strip residual styrene and acrylonitrile below 50 ppm each, a threshold necessary to meet the overall migration limit of 10 mg/dm² established by EU Regulation (EC) No 10/2011 and its amendments. Each production lot undergoes specific migration testing for CHMI monomer (SML 0.05 mg/kg food simulant) using ISO 17714:2007 headspace gas chromatography; published industrial data confirm that when the residual CHMI in the pellet is below 20 ppm, migration into 3% acetic acid simulant at 100°C for 2 hours remains below the detection limit. Downstream conversion employs injection molding with a melt temperature of 230–250°C and mold temperature of 40–60°C; screw back-pressure must be maintained at 8–12 bar to prevent surging caused by the elevated melt elasticity of the CHMI terpolymer. End products are microwaveable rice bowls, lidded casserole inserts, and steam-sterilizable baby bottles where resistance to hot detergent (pH 10, 85°C) must be demonstrated for over 500 cycles without stress-cracking. A negative is that the material is not suitable for microwave browning dishes where surface temperatures may locally exceed 180°C due to insufficient thermo-oxidative stability of the terpolymer; for such applications, a protective silicone overmold is required.UV-curable hard coats applied to polycarbonate automotive glazing substrates subjected to Taber abrasion testing per ISO 1518-1 utilize oligomers in which N-cyclohexylpyrrole-2,5-dione has been pre-reacted into the acrylate backbone to raise crosslink density without the brittleness associated with high-functionality pentaerythritol acrylates. The CHMI-modified urethane acrylate is synthesized by reacting a diisocyanate-terminated prepolymer with 2-hydroxyethyl acrylate and subsequently thermally imidizing the intermediate with CHMI at 80°C for 6 hours in the presence of 100 ppm hydroquinone monomethyl ether inhibitor. The resulting oligomer, containing 3–8 wt% bound CHMI, is formulated with photoinitiator blend (bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide and 1-hydroxycyclohexyl phenyl ketone at a 1.5:1 ratio) and diluted with 15% isobornyl acrylate to achieve a viscosity of 800–1200 mPa·s at 25°C for curtain coating application. After UV exposure at 800 mJ/cm² (UVA), the cured film exhibits a König pendulum hardness (ISO 1522) of 170–185 seconds and a micro-indentation hardness (ISO 14577-1) of 220 MPa, values that correlate with 1,000-cycle Taber haze increase below 5% using CS-10F wheels and 500 g load. Adhesion to polycarbonate tested according to ASTM D3359 (cross-hatch tape pull) must achieve classification 5B after 240 hours of water immersion at 60°C; plasma pretreatment of the substrate at 200 W oxygen flow is mandatory to reach this threshold. The primary commercial application is the factory-applied abrasion-resistant layer on polycarbonate quarter-windows and panoramic roof panels for electric vehicles, where compliance with ECE R43 for head impact testing and optical deviation is required. Field failure data indicate that at CHMI contents exceeding 10 wt% in the oligomer, microcracking develops after 2,000 hours of xenon-arc weathering (ISO 4892-2, cycle 1) due to excessive crosslink density; the recommended upper limit is therefore 8 wt% based on oligomer solids.During production-scale audits of twin-screw compounding lines generating glass-fiber-reinforced PC/ABS for electric vehicle charging infrastructure rated for continuous use at 105°C, pre-compounding of a styrene–N-cyclohexylpyrrole-2,5-dione–acrylonitrile terpolymer (SMI) masterbatch at a loading of 12–18 wt% improves both the heat deflection temperature under 1.8 MPa (ISO 75-2) and the tracking resistance index. The SMI masterbatch, synthesized via continuous bulk polymerization with a CHMI content of 25–30 wt%, is pelletized and subsequently dry-blended with bisphenol-A polycarbonate, bulk ABS, and 15 wt% chopped E-glass fiber prior to feeding into a ZSK 58 co-rotating extruder with a temperature profile climbing from 230°C to 265°C at the die. The presence of CHMI raises the blend’s storage modulus at 120°C by 22% compared to a standard PC/ABS control, as determined by dynamic mechanical analysis (ISO 6721-5) at 1 Hz. Simultaneously, the comparative tracking index measured per IEC 60112 improves from 250 V to 400 V, a critical upgrade for connectors and charging sockets requiring insulation resistance under moist, polluted conditions. A documented processing boundary is the reduction in melt volume-flow rate (ISO 1133, 260°C/5 kg) from 18 cm³/10 min to 8 cm³/10 min when the SMI fraction exceeds 18 wt%; this necessitates raising the back pressure to 25–30 bar during injection molding of thin-wall (1.2 mm) shells to fill the cavity without short shots. Terminal hardware includes CHAdeMO and CCS2 plug housings, on-board charger enclosures, and high-voltage busbar supports required to meet UL 746C outdoor suitability and IEC 60695-2-11 glow-wire ignition at 850°C.

Thermal and Mechanical Performance of ABS with Incremental CHMI Feed Ratios (Emulsion Polymerization)
CHMI in monomer feed (wt%)	Tg by DSC (°C) ASTM D3418	HDT at 1.8 MPa (°C) ISO 75-2	Notched Izod impact (kJ/m²) ISO 180/1A	MVR (220°C/10 kg) ISO 1133
0	104	96	23.5	15.2
5	110	102	19.8	12.4
10	116	109	16.1	10.0
15	123	117	12.3	7.8
20	130	125	8.5	4.6

Regulatory and Standards Compliance Matrix for CHMI-Modified Application Segments
Application Field	Mandatory Standards	Test Method / Clause Reference	Key Performance Requirement
Automotive Interior ABS	VDA 275, VDA 278	ISO 12219-3 for cabin air emissions	Formaldehyde < 10 mg/kg; TVOC < 100 µg/g
PMMA Optical Sheets	DIN EN ISO 12017	ASTM D1003 (haze), ISO 13468-1 (transmission)	Haze < 2.0% at 3 mm thickness
PP/PA6 Under-Hood	UL 94, ISO 1817	DIN 53497 for heat storage	V-2 at 1.6 mm; oil immersion 100°C/168 h
SAN Food Contact	EU 10/2011, FDA 21 CFR 177.1040	ISO 17714:2007 (CHMI migration)	Overall migration < 10 mg/dm²
UV Hard Coat for PC Glazing	ECE R43, ISO 3537	ISO 1518-1 (abrasion), ASTM D3359	ΔHaze < 5% after 1000 cycles; adhesion 5B
EV Charging PC/ABS	IEC 60695-2-11, UL 746C	IEC 60112 (CTI), ISO 75-2 (HDT)	GWIT 850°C; CTI ≥ 400 V

In the production of automotive interior skins requiring low emission profiles and heat resistance above 105°C, N-cyclohexylpyrrole-2,5-dione is incorporated into the emulsion polymerization stage of ABS directly in the monomer feed, eliminating post-reactor compounding steps that could introduce thermal history variability. The process typically operates as a semi-batch seeded emulsion: a polybutadiene latex with a particle size of 280–320 nm swollen with styrene and the full CHMI charge is equilibrated for 2 hours at 30°C, after which acrylonitrile and a potassium persulfate initiator solution are metered in at a rate that maintains a monomer-starved condition at 70°C. CHMI addition is calibrated to 12–18 wt% of total monomers; at 12 wt% the resultant graft copolymer delivers a Vicat softening point of 112°C when precipitated, while the 18 wt% ceiling is set by a sharp increase in coagulum formation beyond 0.3% of batch weight, driven by the monomer’s limited water solubility (0.8 g/L at 25°C) and consequent droplet polymerization. Following coagulation with magnesium sulfate, the crumb is dried in a fluidized-bed dryer to a moisture content below 0.15%, pelletized, and then injection-molded into instrument panel skins, door-trim upper surfaces, and defroster grilles for vehicles required to meet the VDA 275 formaldehyde limit of 10 mg/kg and the VDA 278 TVOC limit of 100 µg/g. The thermal endurance under simultaneous heat and load (ISO 75-2, 1.8 MPa, flatwise) registers 98–102°C depending on rubber content, which prevents gloss-loss and distortion in cabin soak temperatures that can exceed 110°C in equatorial markets. Field observations from a tier-one supplier confirm that at CHMI levels above 18 wt%, the melt flow index drops below 6 g/10 min (220°C/10 kg), making thin-wall molding (1.8 mm) of textured grained panels impractical without elevating melt temperatures into the degradation range of the butadiene phase above 240°C.

Free Quote

Competitive 1-Cyclohexyl-Pyrrole-2,5-Dione 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

Get Free Quote of Bouling Chemical Co., Limited

Flexible payment, competitive price, premium service - Inquire now!

Get A Free Quote Now

Certification & Compliance

1-Cyclohexyl-Pyrrole-2,5-Dione is manufactured under an ISO 9001 quality system and complies with relevant regulatory requirements.
COA, SDS/MSDS, and related certificates are available upon request. For certificate requests or inquiries, contact: sales9@bouling-chem.com.

More Introduction

1-Cyclohexyl-pyrrole-2,5-dione (CAS 1631-25-0), a crystalline maleimide monomer with a saturated six-membered ring substituent, is manufactured as a white to off-white powder exhibiting a melting range of 89–92°C and a purity specification of ≥98.5% by HPLC (area normalization, 254 nm). Its molecular formula C₁₀H₁₃NO₂ and molar mass 179.22 g·mol⁻¹ place it among the sterically hindered N-substituted maleimides. Unlike the widely adopted N-phenylmaleimide, the alicyclic cyclohexyl group eliminates the UV-absorbing aromatic chromophore, reduces acute dermal toxicity, and shifts solubility from aromatic hydrocarbons toward moderately polar esters and ketones, directly affecting processing options in high-temperature polymer synthesis. The free monomer is susceptible to hydrolytic ring-opening above 40°C in aqueous environments; shipments are therefore stabilized with moisture-adsorbing packs and stored under dry nitrogen at ≤25°C. Industrial grades often carry a maximum moisture content of 0.10% (Karl Fischer titration) to suppress maleamic acid formation during melt processing.

What Differentiates Cyclohexyl Maleimide from N-Phenylmaleimide in Radical Copolymerization?

Radical copolymerization kinetics of maleimides with electron-donor comonomers such as styrene or vinyl acetate are governed by the electron-accepting character of the maleimide double bond. The cyclohexyl substituent, being electron-donating via inductive and hyperconjugative effects, lowers the electrophilicity of the double bond compared to the phenyl analog. Published reactivity ratios for the styrene (M₁)/cyclohexyl maleimide (M₂) pair approximate r₁ ≈ 0.05 and r₂ ≈ 0.01, driving copolymerization toward a strongly alternating sequence distribution. In bulk polymerization performed at 80°C with AIBN initiation, the alternating tendency persists up to approximately 55 mol% maleimide feed; beyond that, unreacted crystalline monomer may phase-separate if agitation is insufficient. The resulting alternating copolymer exhibits a glass transition temperature (Tg, midpoint by DSC per ASTM D3418, 10°C·min⁻¹, second heat) typically 10–15°C lower than that of the analogous styrene–N-phenylmaleimide copolymer at equal molar incorporation, yet still offers a substantial T_g elevation over polystyrene homopolymer—commonly reaching 185–200°C for a 48–52 mol% maleimide content. Below is a comparative snapshot of thermophysical properties for alternating copolymers prepared under identical bulk radical conditions (AIBN, 0.5 mol%, 72 h, vacuum-sealed ampoules):

Maleimide Comonomer	Styrene Feed (mol%)	T_g (°C, DSC)	T_d,5% (°C, N₂)	M_w (kDa, GPC)
N-Phenylmaleimide	50	212	395	120–160
N-Cyclohexylmaleimide	50	197	375	100–140
N-Methylmaleimide	50	168	360	80–110

The 5% weight-loss temperature (T_d,5%) under nitrogen measured by thermogravimetry (ASTM E2550) remains above 370°C for the cyclohexyl derivative, which is adequate for most engineering thermoplastic compounding operations. The reduced T_g relative to the phenyl variant translates into a broader processing window in injection molding, where melt temperatures can be maintained 20–30°C lower, decreasing the risk of thermal yellowing in the absence of phenolic antioxidants. Continuous reactive extrusion of styrene–cyclohexyl maleimide copolymers on a co-rotating twin-screw extruder with 40:1 L/D and segmented screw geometry presents specific challenges linked to the monomer’s volatility and crystallinity. Barrel temperatures are profiled from 150°C (feed zone) to 220°C (metering), with vacuum devolatilization applied at zone 8 under −0.08 MPa to strip residual monomer. Because the melting point of the maleimide (89–92°C) sits well below the initial reaction temperature, premature melting and localized pooling in the feed throat can occur if the throat cooling jacket drops below 15°C, leading to bridging and feed surging. To address this, production lines employ a side-stuffer downstream of the melting zone when maleimide feed fractions exceed 20 wt%. Melt viscosity, monitored via an in-line rheometer slit die, must be maintained between 800–1,200 Pa·s at 100 s⁻¹ to avoid excessive pressure fluctuations that compromise strand pelletizing. A documented failure mode involves sublimation of monomer vapor condensing on the die face, causing drip contamination; die-lip heaters are therefore set to 230°C and the die plate is coated with a non-stick fluoropolymer layer. Pre-drying of the maleimide monomer at 40°C under vacuum for 4 h is mandatory when ambient relative humidity exceeds 60%, as hydrolysis to the corresponding maleamic acid introduces carboxylic acid groups that accelerate chain transfer and reduce molecular weight by 15–30%.

Thermoset Latent Curing via Retro-Diels-Alder Deprotection

The Diels-Alder adduct of 1-cyclohexyl-pyrrole-2,5-dione with cyclopentadiene functions as a thermally latent curing agent for epoxy and cyanate ester systems. The crystaline adduct, prepared by a stoichiometric cycloaddition in ethyl acetate below 10°C, remains inert at ambient formulation temperatures. Upon heating above 130–140°C, retro-Diels-Alder cleavage liberates the active maleimide dienophile, which can subsequently participate in Michael addition with nucleophilic hardeners or undergo homo-polymerization initiated by residual peroxides. Differential scanning calorimetry (ASTM E1356) of a diglycidyl ether of bisphenol A (DGEBA) formulation containing 15 phr adduct shows an exothermic onset at 142°C with peak maximum at 168°C (heating rate 10°C·min⁻¹). By contrast, the N-methylmaleimide–cyclopentadiene adduct exhibits retro-DA onset near 110°C, which shortens pot life at 60°C storage to less than 8 h. The cyclohexyl system retains a viscosity below 10 Pa·s at 25°C for over 24 h after mixing. This latency mechanism enables one-part epoxy formulations for composite pre-pregs where B-staging at 80–100°C advances the resin without triggering full crosslinking. The liberated maleimide also acts as a co-reactive diluent, reducing the viscosity of highly filled systems. A critical incompatibility arises when amine-based accelerators such as dicyandiamide or imidazoles are present: the maleimide generated in situ undergoes rapid aza-Michael addition at temperatures as low as 100°C, effectively consuming the active dienophile before it can react with the epoxy matrix. Consequently, latent maleimide curatives are deployed almost exclusively in anhydride- or phenol-cured formulations. In the preparation of polycyclohexylsuccinimide derivatives used as advanced intermediates for CNS-targeted small molecules, 1-cyclohexyl-pyrrole-2,5-dione serves as a dienophile in [4+2] cycloadditions with functionalized dienes. The steric demand of the cyclohexyl ring directs endo/exo selectivity, often favoring the endo transition state when reacting with cyclic dienes such as furan or 1,3-cyclohexadiene. For pharmaceutical applications, the product is supplied to compliance standards including residual cyclohexylamine below 0.05% (GC headspace), sulfated ash ≤0.1% (Ph. Eur. 2.4.14), and heavy metals ≤10 ppm (USP <231> method II). The absence of an aromatic amine degradation product differentiates this maleimide from N-phenylmaleimide-derived intermediates, which can generate aniline under acidic hydrolysis and trigger mutagenic impurity alerts under ICH M7. A typical pharmaceutical-grade specification is summarized below:

Parameter	Specification Limit	Test Method
Assay (anhydrous basis)	99.0–101.0%	HPLC, Ph. Eur. 2.2.29
Melting point	89.0–92.5°C	Ph. Eur. 2.2.14 (capillary)
Water content	≤0.5%	Karl Fischer, Ph. Eur. 2.5.12
Residual solvents (cyclohexane, EtOAc)	≤0.1% each	GC-FID, USP <467>
Sulfated ash	≤0.05%	Ph. Eur. 2.4.14

When Substituting N-Alkylmaleimides in Polyolefin Graft Modification

Maleic anhydride-grafted polypropylene (PP-g-MA) is widely used as a compatibilizer, but the pendant anhydride groups are sensitive to moisture and can undergo ring-opening during long-term storage, altering melt rheology. Post-grafting imidization with 1-cyclohexyl-pyrrole-2,5-dione converts anhydride to the more hydrolytically stable cyclohexylsuccinimide. The reaction is conducted in a nitrogen-purged internal mixer at 180–200°C for 5–10 min without catalyst, producing a product with an imide conversion exceeding 90% (FTIR, disappearance of anhydride C=O at 1790 cm⁻¹). The resultant PP-g-succinimide exhibits a melt flow index (MFR, 2.16 kg/230°C, ISO 1133-1:2022) within 5% of the parent PP-g-MA, indicating minimal chain scission. By comparison, imidization with low-molecular-weight N-alkylmaleimides such as N-butylmaleimide can lead to plasticization and MFR increases of 20–40%, limiting their applicability in high-rigidity formulations. The cyclohexyl group also reduces the vapor pressure of the modifying agent: N-ethylmaleimide volatilizes significantly at processing temperatures, causing vent fouling and occupational exposure concerns, whereas 1-cyclohexyl-pyrrole-2,5-dione remains largely in the melt phase under identical conditions. Published data for long-term water-immersion aging of glass-fiber-reinforced PP composites (ISO 62) indicate that imide-modified grades retain over 85% of their dry tensile strength (ASTM D638-14, Type I specimen) after 1,000 h at 80°C, while the corresponding maleic anhydride-grafted systems typically drop to 60–70% retention.