Cyclohexanone (CAS 108-94-1) is a saturated cyclic ketone used as an intermediate in caprolactam and adipic acid production and as a high-solvency solvent in PVC, polyurethane, and pesticide formulations. This assessment of cyclohexanone manufacturers & capacity in China 2026 separates integrated caprolactam capacity from merchant supply, examines the oxidation and hydrogenation routes, and identifies the specification thresholds that govern downstream use. At integrated nylon complexes, captive ketone flow is consumed by oximation and Beckmann rearrangement; merchant material supplies coating and resin applications where evaporation rate and water miscibility are specified. Chinese production is concentrated in Shandong, Jiangsu, Hunan, Hubei, Fujian, and Zhejiang, and the unit capacity mix is shaped by coal-based benzene availability, hydrogen cost, and phenol–benzene spreads.

Public chemical intelligence databases report Chinese cyclohexanone capacity for 2026 as an uncertainty band rather than a single nameplate total. The lower estimate of 3.8 million tonnes per annum includes integrated units that are operating and under construction with confirmed offtake; the upper estimate of 5.2 million tonnes per annum includes provisional projects, flexible cyclohexanol splitters, and debottlenecking capacity that may be delayed or deferred. Published data for specific plant-level configurations is limited, and individual site capacity differs from nameplate because of feedstock allocation, heat integration, and turnaround scheduling. The market clearing volume in 2026 therefore depends more on captive caprolactam operating rates than on nominal merchant ketone demand.

What Process Intensification Measures Separate Integrated and Merchant Cyclohexanone Routes?

The dominant Chinese route is air oxidation of cyclohexane to KA oil in continuous bubble columns or stirred-tank reactor trains. Typical operating conditions are 140–165°C and 0.8–1.2 MPa. Per-pass cyclohexane conversion is limited to 4–8% to suppress ring opening and polyacid formation; selectivity to K/A oil is maintained in the range 80–88%. Cobalt or chromium carboxylates, sometimes with boric acid or boric anhydride stabilization, are used as homogeneous catalysts. Oxidation also produces adipic acid, glutaric acid, and low-molecular-weight oxygenates; these raise acidity and must be removed by water washing or alkaline neutralization before rectification. Commercial KA oil recovery units typically operate three rectification columns in series: a low-boiler column, a cyclohexanone column, and a cyclohexanol column. The close boiling points of cyclohexanone (155.6°C) and cyclohexanol (161.1°C) require high reflux ratios, vacuum operation, or pressure-swing separation to limit steam consumption.

Integrated caprolactam producers dehydrogenate recovered cyclohexanol to cyclohexanone in shell-and-tube reactors containing copper-zinc/alumina or copper-chromite catalysts at 220–260°C. Per-pass conversion is equilibrium-limited to 55–65%; selectivity to cyclohexanone typically exceeds 98%. The hydrogen off-gas is recycled after cooling and mist elimination. Feed quality constraints are severe: sulfur compounds above 1 mg/kg poison the copper active sites, and residual organic acids above 0.05 mg KOH/g accelerate aldol condensation and fouling. Production-scale catalyst beds typically show pressure drop increases of 0.03–0.08 MPa over 12–18 months when feed acid and sulfur limits are not maintained. Unconverted cyclohexanol is recycled, but heavy oxygenates concentrate in the recycle loop and are purged as distillation tails to prevent fouling of reboiler surfaces.

Merchant suppliers using phenol hydrogenation employ palladium on alumina or Raney nickel in trickle-bed reactors at 120–180°C and 0.1–0.5 MPa. Phenol conversion exceeds 99%, and selectivity to cyclohexanone can exceed 99% under mildly acidic process conditions. The phenol route generates fewer high-boiling oxidation by-products, but residual phenol must be reduced to <50 mg/kg for caprolactam-grade and high-solvency applications. This route is often idled when phenol feedstock cost plus hydrogen does not sustain margin against cyclohexane-derived KA oil; Chinese merchant plants in Shandong and Jiangsu operate intermittently on this feedstock spread. The route converges with oxidation-based production at the rectification step, where the ketone heart cut is specified by distillation range and acidity.

Capacity additions scheduled for 2025–2026 are located mainly in Shandong, Hunan, Hubei, and Fujian. Publicly identified manufacturers include Sinopec Baling Petrochemical, Luxi Chemical, Shandong Haili Chemical, Hubei Sanning Chemical, Jiangsu Haili, and Fujian Tianchen Yaolong. Their routes and captive shares differ materially. Shandong units are often integrated with caprolactam plants and coal-based hydrogen; Jiangsu merchant units are more likely to use phenol hydrogenation and flexible cyclohexanol dehydrogenation. The capacity table below aggregates third-party trade estimates by production cluster; it is not a plant-level engineering survey.

Overcapacity risk is asymmetrically distributed across integrated producers because captive cyclohexanone cannot be curtailed independently without idling ammoximation reactors and downstream polymerization sections. Merchant producers face a different constraint: when phenol route margins invert, units are idled and capacity effectively disappears from merchant availability even though nameplate remains. The upper band of the 2026 capacity estimate therefore does not translate directly into available merchant supply.

If Cyclohexanone Is Stored Below 44°C, What Vapor and Peroxide Risks Remain?

Cyclohexanone is classified as a flammable liquid under GHS H226, with a closed-cup flash point of 43–44°C determined by ASTM D93. It falls within NFPA 30 Class II liquid criteria because the flash point is between 37.8°C and 60°C. Lower explosive limit is approximately 1.1% v/v and upper explosive limit approximately 9.4% v/v at elevated temperature; autoignition temperature is approximately 420°C. Storage below the flash point reduces ignition risk but does not eliminate vapor accumulation in confined headspace. Nitrogen blanketing is specified for tanks above 50 m³ in many Chinese chemical parks; oxygen in the vapor space is commonly controlled to <5% v/v.

Prolonged contact with air can generate trace organic peroxides and acids. Ketone peroxidation is slower than ether peroxidation but is accelerated by dissolved iron or copper ions. Therefore, unlined carbon steel tanks are used only for dry, low-acid material; vertical 316L or lined tanks with floating roofs or internal floating blankets are typical for merchant product. Tank turnovers should be managed because water bottoms and acid sludge promote corrosion pitting. Pre-drying of transfer lines and bulk tanks is required in high-humidity seasons above 60% RH when product must meet 0.03% water for polyurethane-grade orders. Drain-point sampling per batch is considered operational best practice, with color and acidity measured after any tank heel disturbance.

Merchant-Grade Cyclohexanone Purity, Acidity, and Water Limits

Merchant cyclohexanone is sold in industrial grade and polymer grade. The most common merchant specification follows GB/T 10669 with supplementary ASTM methods in export documentation. Purity is determined by gas chromatography area normalization; water limits are more critical for polyurethane and caprolactam customers because water above 0.05% interferes with isocyanate stoichiometry and can hydrolyze catalysts. The table below summarizes typical merchant release parameters. Actual purchase specifications vary by producer and downstream process, and contracted limits may be tighter for polymer-grade shipments.

Application-specific failures on coating and PVC lines are more frequently caused by trace water and acidity than by ketone purity drift. In two-component polyurethane applications, cyclohexanone is used as a letdown solvent; residual water above 0.03% reacts with aliphatic isocyanate hardeners, producing carbon dioxide bubbles and reducing crosslink density. In PVC resin desorption and plastisol cleaning, high-boiling impurities and acidity above 0.005% as acetic acid can catalyze dehydrochlorination and shift the color of heat-aged film. Batch-to-batch variation from merchant suppliers has been observed on pneumatic drum-filling lines when tank heels are not drained; the defect signature is a sudden rise in acidity and a Pt-Co color above 15 Hazen in otherwise in-spec distillate. For caprolactam-grade ketone, sodium and chloride ions should be maintained below 2 mg/kg to protect ammoximation catalysts and downstream nylon 6 polymerization. Avoid prolonged contact with primary amines in blending operations because imine formation removes reactive isocyanate stoichiometry and can gel storage lines. If oxidative by-products exceed specified limits, post-treatment with activated carbon or mild alkali scrubbing is used, but this can introduce water and must be followed by vacuum drying.