Products
Products
Products
| HS Code | 266058 |
| Chemical Name | Cyclohexane |
| Cas Number | 110-82-7 |
| Molecular Formula | C6H12 |
| Molecular Weight | 84.16 g/mol |
| Appearance | Colorless liquid |
| Odor | Mild, petroleum-like odor |
| Density | 0.779 g/cm3 at 20°C |
| Melting Point | 6.47°C |
| Boiling Point | 80.75°C |
| Flash Point | -20°C (closed cup) |
| Autoignition Temperature | 245°C |
| Solubility In Water | Insoluble (0.008 g/100 mL at 20°C) |
| Refractive Index | 1.4262 at 20°C |
| Vapor Pressure | 77.6 mmHg at 20°C |
| Viscosity | 0.894 cP at 25°C |
As an accredited Hydrogenated Benzene factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Hydrogenated benzene (cyclohexane) packaged in 25-liter steel drums with secure closures, labeled flammable, for safe transport and storage. |
| Container Loading (20′ FCL) | Hydrogenated benzene (cyclohexane) is loaded in a 20′ FCL in properly sealed, UN-approved drums, tightly secured and labeled for safe transport. |
| Shipping | Hydrogenated benzene (cyclohexane) is a highly flammable liquid. Ship as UN 1145, Class 3, Packing Group II, in tightly sealed, approved containers. Keep away from heat, sparks, oxidizers, and open flames. Ground containers against static; provide ventilation. Follow established maritime, air, road, and rail dangerous-goods regulations. |
| Storage | Hydrogenated benzene (cyclohexane) should be stored in tightly sealed containers away from heat, sparks, and open flames. Use approved flammable-liquid storage cabinets in a cool, well-ventilated area, isolated from strong oxidizers. Keep containers grounded and bonded to prevent static discharge. Ensure clear labeling and access to appropriate fire-extinguishing equipment. |
| Shelf Life | Hydrogenated benzene (cyclohexane) remains stable for years when stored properly in sealed containers, away from oxidizers and ignition sources. |
Where hydrogenated benzene (cyclohexane) enters the polyamide 66 supply chain, the material is not diluted into a minor formulation additive; it is the primary carbon substrate for the liquid-phase oxidation train. Industrial oxidation plants sparge air through cyclohexane in stirred bubble-column reactors at 0.8–1.2 MPa and 150–170 °C using cobalt naphthenate at 0.1–0.3 wt% metal relative to fresh cyclohexane feed; per-pass conversion is deliberately restrained to 4–6 mol% because higher conversion accelerates ring-opening by-products, esters, cleavage acids, and COx formation. The resulting cyclohexanol/cyclohexanone mixture is typically obtained at 75–85 mol% combined selectivity, depending on whether boric acid is used as a selectivity moderator. The downstream nitric acid oxidation of the KA oil to adipic acid is run at 60–90 °C and 0.5–1.0 MPa in titanium-lined or glass-lined equipment with copper and vanadium catalysts; molar yield from KA oil to adipic acid is commonly reported in the 90–94% range. Compliance for polymer grades derived from this intermediate is verified against ISO 1874-1 for designation, FDA 21 CFR 177.1500 for nylon food-contact applications, and EU 10/2011 with an overall migration limit of 10 mg/dm². Because cyclohexane is the sole carbon source, fresh feed is blended with recycled cyclohexane at a mass ratio of 2.5:1 to 4:1, with the recycle continuously purged through low-boiler and high-boiler distillation to remove ring-opened impurities. The formulation ratio at the nylon 66 salt stage is 60–70 wt% aqueous salt solution adjusted with hexamethylenediamine to a pH of 7.6–8.0; final polycondensation is operated as a continuous two-stage process with a finish temperature of 270–285 °C under a nitrogen sweep. Finished product types include injection-molding PA66 pellets with viscosity numbers from 140–160 mL/g, extruded tire-cord yarns, and compression-molded stock shapes.
For caprolactam producers, cyclohexane consumption is governed less by additive loading than by the integrated mass balance across oximation and Beckmann rearrangement. The oxidation step overlaps with the adipic acid route but is tuned to maximize cyclohexanone content in the KA oil, with the ketone recovered by reduced-pressure distillation before conversion to cyclohexanone oxime using hydroxylamine sulfate and ammonia. The oxime is then rearranged in excess oleum at 90–120 °C, and the reaction mass is neutralized with ammonia to release caprolactam; the crude lactam is extracted in pulsed countercurrent columns and refined by hydrogenation and distillation. Plant-level cyclohexane consumption for integrated caprolactam manufacture typically falls between 1.05 t and 1.10 t per metric ton of caprolactam, reflecting the molar carbon demand of 0.74 t/t plus yield losses in the oxidation and rearrangement sequence. This is a meaningful ratio because it sets the unit cost and the purge volume of low-value organic streams. Compliance for PA6 derived from this route is checked against ISO 1874-1, FDA 21 CFR 177.1500 for food-contact use, and EU 10/2011 for plastic migration; caprolactam monomer content in final PA6 is typically controlled below 0.5 wt% by post-polymerization hot-water extraction. Hydrolytic polymerization is performed in two-step VK tube reactors at 250–270 °C with 2–3 wt% water as ring-opening agent and residence times of 10–20 h; the melt is then spun or pelletized under nitrogen. Finished product types include PA6 film, BCF carpet yarn, and engineering compounds for injection molding where viscosity number is specified under ISO 307 in sulfuric acid at 25 °C.
In solution-polymerized styrene-butadiene rubber and polybutadiene production, cyclohexane serves as a low-polarity inert diluent that dissolves butadiene and styrene monomers while maintaining low solution viscosity for heat removal and chain-transfer control. The solvent is dried over molecular sieves until moisture is below 5 ppm; oxygen in the reactor feed is reduced below 10 ppm by vacuum deoxygenation or nitrogen stripping because residual oxygen deactivates the n-butyllithium initiator. Cyclohexane is typically charged at a solvent-to-monomer mass ratio of 5.0:1 to 7.0:1, which corresponds to 80–86 wt% of the reactor feed and leaves a polymer solids content of 12–20 wt%. Polymerization is conducted in a train of continuous stirred-tank reactors with internal cooling coils at 40–80 °C and 0.3–0.5 MPa; living-chain coupling is performed with tin or silicon halides to introduce branched architecture in tire-grade SSBR. The solvent is then removed by steam stripping, and the wet rubber is dewatered in expeller presses and finished in a twin-screw devolatilizing extruder with L/D ratio above 36:1. Compliance for this application is anchored to ISO 2322 for evaluation procedures, ISO 289-1 for Mooney viscosity, and Regulation (EC) No 1907/2006 under REACH for registration and restricted substances; tire-manufacturing customers additionally reference Regulation (EC) No 1222/2009 for label performance. Operating limitations include the use of polar Lewis-base randomizers such as tetrahydrofuran in low doses of 0.1–0.5 wt% relative to monomer because higher randomizer levels narrow the molecular weight distribution and reduce cold-flow resistance of the finished bale. Finished product types include SSBR grades for low-rolling-resistance tire treads, high-cis polybutadiene rubbers, and styrenic block copolymers for bitumen modification.
| Parameter | Control range | Measurement method |
|---|---|---|
| Cyclohexane share of reactor feed | 80–86 wt% | mass balance, GC |
| Solvent-to-monomer mass ratio | 5.0:1 to 7.0:1 | Coriolis metered feed |
| H₂O in solvent | < 5 ppm | Karl Fischer titration |
| O₂ in reactor headspace | < 10 ppm | headspace analyzer |
| Polymerization temperature | 40–80 °C | internal RTD |
| Mooney viscosity ML 1+4 at 100 °C | 55–65 MU | ISO 289-1 |
Cyclohexane enters solvent-borne industrial coatings as a saturated hydrocarbon diluent in alkyd, chlorinated rubber, and acrylic systems where fast evaporation and moderate solvency are required without the photochemically reactive aromatic content of toluene or xylene. The addition ratio in a ready-to-use coating is typically 10–30 wt% of the total solvent package, with the balance made up by oxygenated solvents such as butyl acetate or methyl ethyl ketone; below 10 wt% the viscosity reduction is insufficient for spray application, and above 30 wt% the flash point of the solvent blend falls below the threshold for non-flammable storage classification measured by ASTM D3278. Manufacturing is carried out in a high-speed dissolver with tip speed of 18–22 m/s to wet pigments, followed by bead-mill grinding to a Hegman gauge fineness of 15–25 µm, then letdown and viscosity adjustment with cyclohexane-diluted resin solution. VOC content of the finished product is quantified by ISO 11890-2; process emissions at industrial coating lines must be balanced against the emission limit values of EU 2010/75/EU Annex VII Part 5, while product classification uses Regulation (EC) No 1272/2008 for flammable liquid classification. A known processing boundary occurs in high-humidity spray booths: at relative humidity above 60–70% RH, rapid evaporation of cyclohexane cools the applied film and can induce moisture condensation and surface blush, requiring a retarder solvent or forced dehumidification. Finished product types include fast-drying anti-corrosive primers, alkyd machinery topcoats, and rubber-based protective coatings for steel substrates.
When cyclohexane is selected as a crystallization solvent in active pharmaceutical ingredient purification, the controlling variable is not solvency alone but the residual solvent limit fixed by ICH Q3C R8 and Ph. Eur. chapter 5.4. Cyclohexane is listed in Class 2 with a permitted daily exposure of 38.8 mg/day, which translates to a concentration limit of 3880 ppm for a 10 g/day drug product intake; this limit drives the drying endpoint rather than the initial dissolution ratio. The solvent-to-crude-solid charge is commonly set at 5–15 mL/g, depending on the solubility curve of the target molecule in cyclohexane, and the batch is dissolved in a glass-lined reactor at 60–80 °C under nitrogen. Crystallization is then controlled by cooling at 0.1–0.3 K/min to 2–8 °C, with intermittent seeding to limit primary nucleation and to avoid oiling-out, because cyclohexane has a relatively low dielectric constant and can promote oiling-out for polar intermediates if cooling is uncontrolled. Final isolation is performed in an agitated nutsche filter dryer with vacuum drying at 40–50 °C and 10–50 mbar; residual cyclohexane is then verified by head-space gas chromatography against the 3880 ppm monograph limit. Downstream equipment must be explosion-protected for Zone 1 interior under EN 60079-10-1 because cyclohexane forms flammable vapour-air mixtures above its flash point of -18 °C; inertization is standard practice. Finished product types include recrystallized APIs, intermediate salts, and high-purity lipids where aromatic solvents are prohibited by the release specification.
Competitive Hydrogenated Benzene prices that fit your budget—flexible terms and customized quotes for every order.
For samples, pricing, or more information, please contact us at +8615365186327 or mail to sales3@ascent-chem.com.
We will respond to you as soon as possible.
Tel: +8615365186327
Email: sales3@ascent-chem.com
Flexible payment, competitive price, premium service - Inquire now!
Hydrogenated benzene, specified industrially as cyclohexane (CAS 110-82-7; EC 203-806-2), is the fully saturated six-membered alicyclic hydrocarbon C₆H₁₂ produced by catalytic hydrogenation of benzene. Commercial supply is differentiated by grade designation rather than proprietary model number, with high-purity, low-benzene, and technical grades being most common. The material is a clear, colourless liquid with a boiling point of 80.7 °C, freezing point of 6.5 °C, density of approximately 0.7785 g/mL at 20 °C, and closed-cup flash point of −18 °C by ASTM D56-21a. Its primary tonnage use is as an intermediate for cyclohexanone/cyclohexanol oxidation feedstock, followed by solvent, extraction, and viscosity-reduction applications. Unlike benzene, it is non-aromatic and fully saturated; unlike n-hexane, it is cyclic with higher hydrocarbon-resin solvency; and unlike methylcyclohexane, it has a lower boiling point and faster solvent-release profile.
Residual benzene is the principal specification variable because it determines odour, regulatory classification, and downstream catalyst compatibility. In high-purity product, benzene carryover is typically held at ≤50 mg/kg, with the most restrictive polymerization and pharmaceutical grades at ≤10 mg/kg. The limit is maintained less by distillation alone than by hydrogenation reactor space velocity, hydrogen-to-aromatic feed ratio, and catalyst deactivation profile. In fixed-bed operation, declining catalyst activity increases benzene slip before total conversion falls below specification. Operators often compensate by raising inlet temperature within a narrow band of 180 °C to 230 °C, but adiabatic temperature rise constrains the outlet temperature. Interstage cooling and cold hydrogen quench are used to hold overall benzene conversion above 99.9 %. Trace benzene in the finished material is measured by capillary gas chromatography using ASTM D6229 or an equivalent hydrocarbon impurity method.
Specification limits for two representative commercial grades are shown below. Values are indicative of certificates of analysis and are not maximum or minimum legal limits.
| Parameter | High-purity grade | Technical grade | Test method |
|---|---|---|---|
| Purity | ≥99.9 wt% | ≥98.0 wt% | GC-FID |
| Benzene | ≤50 mg/kg | ≤1000 mg/kg | ASTM D6229 |
| Total sulfur | ≤1 mg/kg | ≤5 mg/kg | ASTM D5453 |
| Water | ≤50 mg/kg | ≤100 mg/kg | ASTM E1064 |
| Non-volatile residue | ≤5 mg/100 mL | ≤10 mg/100 mL | ASTM D1353 |
| Flash point | −18 °C | −18 °C | ASTM D56-21a |
| Density at 20 °C | 0.778–0.779 g/mL | 0.776–0.780 g/mL | ASTM D4052-18a |
| Distillation range | 80.4–81.0 °C | 80.0–82.0 °C | ASTM D1078 |
Solvency differences are measurable in Hildebrand solubility parameters. Cyclohexane has a Hildebrand value of 16.8 MPa1/2, whereas toluene is 18.2 MPa1/2 and benzene is 18.6 MPa1/2. The removal of the aromatic ring reduces polar and hydrogen-bonding contributions, making cyclohexane weaker for aromatic hydrocarbon resins, high-styrene copolymers, and some acrylics. It is retained for hydrocarbon resins, polyolefins, alkyds, and organosilicon systems. Vapour pressure at 20 °C is approximately 10.4 kPa, and the material forms flammable vapour at ambient processing temperatures. Closed-loop dispensing, nitrogen blanketing, and vapour recovery are required where processing exceeds 30 °C. When replacing toluene in a coating formula, viscosity response must be checked with drawdown films prepared under ASTM D823, because reduced solvency can produce resin flocculation during letdown or dry-film gloss loss.
Cyclohexane-based degreasing formulations require acid-scavenging inhibitor packages because light and oxygen generate trace peroxides and organic acids during storage. In vapour-phase degreasing, the kauri-butanol value is approximately 54 by ASTM D1133, which is lower than toluene and significantly less aggressive for heavy bituminous soils, but acceptable for paraffinic and naphthenic oils. The flash point of −18 °C requires closed-loop degreasers with condensing zones held at 10 °C to 15 °C to maintain solvent recovery above 95 %. Stainless steel immersion chambers and continuous water separation are specified because water solubility in cyclohexane is approximately 50 mg/kg at 20 °C; free water accelerates corrosion at the vapour/liquid interface. Corrosion evaluation of inhibited formulations is commonly performed by ASTM D130 copper strip testing after 3 h at 50 °C.
In high-density polyethylene extrusion and membrane casting, cyclohexane is added at 5–15 wt% to reduce melt viscosity and permit barrel temperature reductions of 10–20 °C relative to undiluted profiles. Twin-screw extruders with L/D ratios of 36:1 to 52:1 are used for high-shear dispersion. Residual solvent is removed in vacuum devolatilisation zones at −0.08 MPaG and 180 °C. The low solvency for polar additives requires pre-dispersion of stabilisers to prevent agglomeration. Published data for this specific configuration is limited; pilot trials at the intended dilution ratio are required before line qualification.
Benzene hydrogenation to cyclohexane is strongly exothermic, with heat of reaction approximately −206 kJ/mol. A runaway or hot-spot event is managed by maintaining a molar hydrogen-to-benzene feed ratio above 3:1 and splitting feed across multiple catalyst beds. In a three-bed adiabatic reactor with intermediate quench, typical inlet temperatures are staged from 150 °C to 220 °C, with outlet temperatures not exceeding 260 °C. Sulfur and carbon monoxide in the benzene feed poison nickel catalysts at mass concentrations as low as 1 mg/kg, requiring feed pre-treatment by adsorption or hydrodesulphurisation. Published data for specific deactivation rates are limited because catalyst life depends on feed grade and regeneration frequency, but industrial operators commonly schedule regeneration cycles at intervals of 3–12 months. The hydrogenated product stream is condensed, separated from excess gas, and distilled. Because benzene and cyclohexane boil within 0.6 °C of each other, conventional distillation demands high reflux ratios; benzene is often removed by extractive distillation with a polar entrainer or by selective adsorption.
Oxidation feedstock quality control is stricter than general solvent grade control. KA oil production by air oxidation is carried out at 140–180 °C and 0.8–1.5 MPaG in bubble-column or stirred autoclave reactors, with cobalt and chromium species used as oxidation catalysts. The reaction is free-radical in character; iron contamination accelerates unselective hydroperoxide decomposition and increases ring-opening by-products. Limits for iron in high-purity cyclohexane are therefore commonly set at ≤0.1 mg/kg, while peroxide content is controlled below 1 mg/kg as active oxygen to prevent premature initiation during storage. Conversion per pass is deliberately limited to 4–8 % to preserve selectivity to cyclohexanol and cyclohexanone; higher conversion increases adipic, glutaric, and succinic acid precursors and lowers KA oil yield. Reactor off-gas is scrubbed to recover entrained cyclohexane, and the crude KA oil is concentrated by distillation and caustic washing.
When cyclohexane is selected over methylcyclohexane, the decisive variables are recovery energy and freeze protection. Methylcyclohexane has a boiling point of 101 °C, density of 0.770 g/mL at 20 °C, and flash point of approximately −4 °C. Cyclohexane is selected when recovery energy is limited and higher volatility aids solvent removal. In pharmaceutical extraction, the lower boiling point reduces thermal exposure of heat-sensitive intermediates; distillation recovery can be completed at reboiler temperatures below 100 °C. The freezing point of 6.5 °C is a practical concern: storage tanks and transfer lines exposed to winter conditions require heat tracing or internal steam coils. Methylcyclohexane freezes at −126 °C, eliminating freeze protection in cold climates, but its higher boiling point increases solvent removal energy. The selection therefore balances solvent recovery energy against freeze-protection capital cost.
| Instrument or standard | Reporting obligation or test | Typical acceptance criterion |
|---|---|---|
| EU REACH (EC) No 1907/2006 | Registration and substance safety report | Tonnage-dependent registration |
| CLP (EC) No 1272/2008 | Classification and labelling | Flam. Liq. 2 (H225); Asp. Tox. 1 (H304) |
| US TSCA Inventory | Chemical inventory listing | CAS 110-82-7 |
| FDA 21 CFR 175.300 | Resinous and polymeric coatings | Confirm current solvent inclusion status |
| ASTM D6229 | Trace benzene in hydrocarbon solvents | ≤50 mg/kg high-purity grade |
| ASTM D5453 | Total sulfur by UV fluorescence | ≤1 mg/kg high-purity grade |
Storage requires flameproof electrical classification because vapours are heavier than air and can accumulate in pits and drains. The flammable range in air is approximately 1.3 % v/v to 8.4 % v/v. Storage tanks are nitrogen-inerted to keep oxygen below 8 % v/v in the vapour space, particularly above 25 °C. Carbon steel is acceptable for dry material, but moisture ingress creates acidic corrosion conditions at weld seams. Pumps with double mechanical seals and hydrocarbon-resistant elastomers are specified. Avoid contact with strong oxidisers; inhibitor-free material should be consumed within 6 months when stored above 25 °C.
