Why Nylon 66 / Polyurethane Can't Do Without Adipic Acid (AA)? From Molecular Structure to the Industry Chain

What Is Adipic Acid? — Starting from Molecular Structure

Production Process and Key Raw Materials (Cyclohexane Oxidation / Cyclohexene Method / Bio-based)
Updated: late July 2026 | Haiyu Zhonglong Chemical

📑 Table of Contents

Downstream Applications: Nylon 66, Polyurethane, PBAT, etc.
I. What Is Adipic Acid? — Starting from Molecular Structure
Adipic acid (
PTA (
Industry Outlook
References and Data Sources

Adipic Acid, AA

, CAS 124-04-9) systematic name 1,6-hexanedioic acid (also known as "adipic acid"), molecular formula C₆H₁₀O₄. It is the largest-volume and most widely usedaliphatic straight-chain dicarboxylic acid among such acids; a single molecule links three important industry chains: nylon, polyurethane, and degradable plastics. HOOC − (CH₂)₄ − COOH (Straight chain: a carboxyl group −COOH at each end, with four methylene groups −CH₂− in the middle)

straight-chain aliphatic dicarboxylic acid
: the symmetric carboxyl groups at both ends provide difunctionality and can polycondense with amines/alcohols

💡 Core Structural Features
• Typical • In the middle, (CH₂)₄
four methylene groups make the molecule flexible, giving downstream polymers good toughness • With good symmetry and easy crystallization, industrially it exists aswhite crystalline powder
, facilitating storage, transportation, and metering124-04-9White crystalline powder or monoclinic prismatic crystals, faint acidic taste

1.1 Overview of Key Physicochemical Properties

Indicator	Value / Description
Molecular Formula	aliphatic straight-chain dicarboxylic acid
CAS No.	Approx. 152 °C
Appearance	Approx. 1.36 g/cm³ (20°C)
Melting Point	Slightly soluble in water (approx. 1.4 g/L, 25°C), soluble in ethanol, ether, and other organic solvents
Density	Approx. 767 mg KOH/g
Solubility	1.2 Why It Is the Industrial Star Among "Dicarboxylic Acids"
1.2 Why It Is the "Throat" of the Polyester Industry Chain	Adipic acid has a triple identity: it is the

Data sources: PubChem; ChemSpider; common physical-property parameters from the China Chemical Products Handbook

nylon 66 salt

synthesis raw material, thepolyester polyol key skeleton dicarboxylic acid, and also thePBAT essential monomer for degradable plastics. A single C₆ molecule connects all three tracks — engineering plastics, elastomers, and green materials — which is exactly its irreplaceable underlying logic.2.1 Mainstream Process: Cyclohexane Oxidation (KA Oil Method)The vast majority of global adipic acid uses this route:

II. Production Process and Key Raw Materials

Benzene → hydrogenation to cyclohexane → air oxidation to cyclohexanol/cyclohexanone mixture (KA oil) → nitric acid oxidation → adipic acid crystallization and refining

. The process is mature with strong scale effects and is currently the lowest-cost mainstream solution.: 1 tonne of adipic acid consumes approx. 0.7–0.72 tonnes of benzene

📊 Cost Perspective — the benzene price almost determines the cost center of adipic acid, which is why "benzene rises but acid does not necessarily follow, squeezing profits" has become an industry norm.2.2 Cyclohexene Method (Asahi Kasei Process) — GreenerImproved route:

partial hydrogenation of benzene to cyclohexene → hydration to cyclohexanol → nitric acid oxidation

. Compared with the cyclohexane method, it has fewer by-products and lower three-waste emissions, making it one of the important directions for green transformation.2.3 Bio-based Route — Zero-Carbon DirectionUsing

furfural

extracted from corncob, cellulose, and other biomass as raw materials, adipic acid is produced via enzymatic catalysis or microbial fermentation, significantly reducing carbon: Bio-based Progress Snapshot • Huafon Group obtained in 2024

✅ ISCC PLUS:
international certification, with the capability to supply bio-based / bio-circular adipic acid • "Zero-carbon" nylon 66 technology was officially commercialized in Q2 2026; compared with the traditional benzene oxidation method, carbon is reduced by approx. 42%
• The team of Academician Tan Tianwei of Beijing University of Chemical Technology completed a 1-tonne pilot test
, with a theoretical yield of 87% for the new biosynthetic route • Nanchang University / Suzhou University of Science and Technology's new "two-step furanic acid" process achieves an adipic acid yield of 91.4%
• In 2026, China's bio-based adipic acid enteredthe 10,000-tonne demonstration
stage (estimated 30,000–50,000 tonnes)Cyclohexane OxidationBenzene, nitric acid

2.4 Comparison of Mainstream Process Routes

Route	Key Raw Materials	Features	Representative / Status
Mature, low cost, higher three-waste	Mainstream (Huafon / Shenma / Hualu)	Cyclohexene Method	Benzene, water
Fewer by-products, greener	Asahi Kasei, etc.	Biomass (furfural, etc.)	10,000-tonne demonstration (Huafon / BUCT)
Bio-based Method	Note: The above process descriptions are compiled from public technical literature and industry reports; industrial production is mainly based on the cyclohexane oxidation method.	Low-carbon, high value-added	III. Downstream Applications: Nylon 66, Polyurethane, PBAT, etc.

3.1 Nylon 66 (PA66) — the Largest Global Downstream

Adipic acid and

hexamethylenediamine (HMDA, from adiponitrile)

condense to form nylon 66 salt, then polymerize into PA66, widely used in engineering plastics, industrial yarn, carpet yarn, and automotive parts. With the domestic adiponitrile technology breakthrough, PA66 localization is accelerating and is regarded as the largest future demand increment source for adipic acid.3.2 Polyurethane (PU) — the Largest Domestic Consumption FieldAdipic acid esterifies with diols (BDO / EG / DEG) to synthesize

, which is the core raw material for PU elastomers, shoe-sole stock solution, PU paste, synthetic leather, TPU, coatings, and adhesives; its derivative

adiponitrile → HDIPBAT is also used for PU curing agents. In the domestic demand structure, PU is the largest outlet for adipic acid.3.3 PBAT Degradable Plastic — Emerging Growth EngineAdipic acid is the

PBAT (poly(butylene adipate-co-terephthalate))

key comonomer. With the expansion of the "plastic ban," PBAT capacity continues to expand, and demand for adipic acid is rapidly increasing, becoming an important support for absorbing new capacity.Plasticizer: adipate esters (e.g., dioctyl adipate, DOA) as PVC cold-resistant plasticizers

3.4 Other Applications

Food / Pharmaceutical: acidulant, buffer (listed by the FDA as a GRAS safe substance)
Intermediate: via adiponitrile to hexamethylenediamine, extending into the nylon chain
Lubricating Oil Additive and other fine-chemical uses
Polyurethane (PU)~59%

3.5 Downstream Demand Structure (Domestic vs Global)

Application Field	Share of Domestic Demand	Share of Global Demand	Remarks
~30%+	Domestic PU paste 38%+ / shoe sole 21%	Nylon 66 (PA66)	~17%
~51%	Global mainstay, lower domestically	PBAT / Degradable	Fastest growing
Plasticizer / Other	Emerging	Emerging	Cold-resistant plasticizing, food, etc.
: Domestic demand is "PU-heavy, nylon-light," exactly the opposite of the global "nylon-dominated" structure. The main reason is that domestic PA66 has long been constrained by	Remaining	Remaining	adiponitrile imports

⚠️ Structural Difference Warning; with localization advancing, the nylon share is expected to rise systematically, which will be the biggest variable in adipic acid's demand pattern.Data sources: Zhongyan Puhua "2026 Adipic Acid Industry Development Trend Analysis"; industry review (2026)China is already the world's largest producer and consumer. According to Huafon Chemical's annual report and industry disclosures,

domestic capacity in 2025 was approx. 3.836 million tonnes, output 2.57 million tonnes (YoY +3.3%), and apparent consumption 2.038 million tonnes (YoY +6.42%)

by the end of 2025, domestic PTA total capacity had exceeded 94.70 million tonnes (effective capacity approx. 94.90 million tonnes)

4.1 Capacity and Supply-Demand Pattern

; the industry operating rate was only approx. 55–60%, in the overcapacity range.Huafon Chemical, with 1.355 million t/y capacity, ranks first globally and approx. 45% domestic market share; the rest are Shenma, Hualu Hengsheng, Haili, Hengli, etc.; the industry CR5 is expected to exceed 75% in 2026, up from over 65% in 2024.
Market leadership is highly concentrated: : Nominal capacity continues to expand, but effective capacity contracts (units proactively cut load/maintenance), showing "overcapacity + low operating rate + rising leader market share

📊 Current Pattern Interpretation" typical shakeout-phase features.

4.2 Complete Price Chain: Upstream Raw Material → Adipic Acid → Downstream

Benzene ~8800 yuan/t → Cyclohexane / Cyclohexene → Nitric acid oxidation → Adipic acid 6500~7500 yuan/t → Nylon 66 / Polyurethane / PBAT → End products

4.3 Current Market Prices (2026, collected from public platforms, for reference only)

Item	Spec / Brand	Price Range (yuan/tonne)	Data Source / Date
5,079 (up 6.04% vs. early year)	T/T Mainstream Price	6,500–7,500	SCI99 / Longzhong 2026
5,079 (up 6.04% vs. early year)	2025-12 Weekly Average	6,530	SCI99 12-04
Manufacturer Quote	Hualu Hengsheng (ex-factory)	7,900 (weakening on 07-07)	SunSirs 07-07
Manufacturer Quote	Shandong Dehe	8,000 (strengthening on 07-16)	SunSirs 07-16
Huafon Disclosure	H1 Highest Price	12,000	Huafon / Sina 2026H1
Huafon Disclosure	Q2 Average	8,894 (YoY +10.66%)	Huafon 2026Q2
Upstream: Benzene	East China Negotiation (2026-04-17)	8,800–8,920 (YoY +42%)	Industry Review 04-17

Affected by the Middle East geopolitical conflict, Brent crude once spiked at the start of 2026 (touching 119.5 USD/barrel intraday in March), pushing up the cost center of PX and PTA; the H1 2026 average PTA price rose 24% YoY.

In 2025, the global average m-Xylene price rose approx. 15% YoY to 1,100 USD/tonne (CFR China), providing strong cost support for PIA from the raw-material side.

① Upstream: Strong Benzene Support
Affected by the Middle East geopolitics and other factors, benzene rose in East China to 8,800–8,920 yuan/tonne in April 2026, up 42% YoY, providing strong cost support for downstream.

② Midstream: Profits Squeezed
Estimated at 0.7–0.72 tonnes of benzene per tonne, raw material cost alone is approx. 6,200–6,400 yuan/tonne; adding nitric acid, energy, and labor, the full cost approaches the mainstream selling price, and processing profit is thin, forcing some production lines to cut load or go into maintenance.

⚠️ ample supply + tightening demand: Longzhong / SCI99 have repeatedly pointed out that adipic acid shows "cost support vs. weak demand" — strong upstream, weak downstream, lagging price transmission, and the industry is stuck in a stalemate.

③ Supply-Demand: Overcapacity + Rigid-Demand Procurement
With an industry operating rate of 55–60%, downstream mostly "buys as needed" with low stocking willingness, showing an overall "loose supply-demand + stagnant prices" pattern.
④ Export Side: Structural Restructuring
In 2025, China's adipic acid exports were approx. 490,000 tonnes (approx. 23% of output, export value approx. 4.18 billion yuan); the EU's Nov 2025 preliminary anti-dumping duties of 28.6%–46.8% forced exports to shift to Asia, the Middle East, and Africa.

• Currently in a historically relatively low level + weak oscillation:
range, suitable for phased positioning rather than one-time large ordershistorically relatively low + oscillationthe m-Xylene price
and the unit maintenance/restart rhythm — any variable may trigger short-term fluctuationsthe benzene price4.5 Recent One-Year Price Trend (Cross-verified with Public Data)
• Domestic high-purity adipic acid (≥99.7%) already dominates the market; it is recommended to first take samples for lab-trial comparison

Event

East China Mainstream Price (yuan/tonne)	Trend	2024-05	Year high
2025-11	Unit maintenance, thin trading	Around 6,500	↓ 7,250–7,450 (monthly avg 7,389)
2026-01	Cost rebound, average price rising	7,200–7,500	↑ 5,079 (average)
11,100	Benzene surge pushed up	Approx. 10,300	⚠ Year low
5,925–6,025	Manufacturer quotes diverging	6,500–8,000	Concentrated release of new capacity (2026 may exceed 7 million tonnes); operating rate may fall to 75%; backward capacity phased out

Direction

💡 Core Judgment

Impact	Sustained Demand Growth	Driven by rising polyester bottle flake output; expanding applications in pharmaceuticals/electronic chemicals
Green Transformation	10,000-tonne bio-based demonstration, zero-carbon nylon 66 commercialized in 2026Q2, carbon reduced by approx. 42%	Improving preform processing and bottle transparency to meet high-end packaging
Greening	Electronic-grade and bio-based products escape bulk-price involution	Import dependence down to 34.47%, domestic technology rapidly improving
New Demand Engine	PA66 localization (adiponitrile breakthrough) + PBAT (plastic ban) dual-wheel drive	Tightening environmental regulations; bio-based IPA and clean processes accelerating implementation
Rising Concentration	CR5 expected to exceed 75%; backward capacity phased out	PC optical/medical localization rate <30%, large import-substitution space; epoxy resin shifting to high-end wind power/electronics
Export Restructuring	Avoiding EU anti-dumping, shifting to Asia/Middle East/Africa; green certification becomes competitiveness	PC "anti-involution" consolidation (Luxi / Cangzhou Dahua); basically no new PC capacity in 2026, spread widens

✅ loose supply + low prices; in the long term, it will follow the four main lines of "Overcapacity + low prices" to complete the leap from "import dependence" to "independent supply." Whoever first positions in bottle flake increment and bio-based high value-added will grasp the initiative of the next cycle.low-carbonization, high-end upgrade, and integration" the three main lines to leap from "scale expansion" to "high-quality development." Whoever first positions in bio-based and nylon 66 increment will grasp the initiative of the next cycle.

Figure: Adipic acid molecular structure and downstream industry chain applications (compiled by Haiyu Zhonglong, illustrative)

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📌 , or add our WeCom (enterprise WeChat), and the Haiyu Zhonglong Chemical team will provide you with: • High-purity isophthalic acid (multiple domestic brands available, bottle-flake grade / resin grade) • Supporting supply of polyester bottle flake / unsaturated resin raw materials
• High-purity adipic acid (multiple domestic brands available, ≥99.7%)
• Supporting supply of nylon 66 / polyurethane raw materials
[1] Huanjing Industry Research Institute. 2025 China Isophthalic Acid Industry Development Status and Outlook [EB/OL].

📚 [2] Zhiyan Consulting. 2025 China Isophthalic Acid Industry Status and Development Trend Analysis [EB/OL].
[1] Huafon Chemical 2025 Annual Report; Sina Finance. Adipic Acid Capacity and Industry Pattern [EB/OL]. 2026-03.
[2] SCI99. Adipic Acid Weekly Review (Prices Slightly Pushed Up Amid Concentrated Maintenance) [EB/OL]. 2025-12-04.
[3] SunSirs. Adipic Acid Commodity Intelligence and Quotation Dynamics [EB/OL]. 2026-07-07/16.
[4] Longzhong Information (Mysteel). Adipic Acid Unit Dynamics and Daily Review [EB/OL]. 2025-12 / 2026.
[5] Zhongyan Puhua / ChinaBaogao. 2026 Adipic Acid Industry Development Trend Analysis [EB/OL].
[6] Achilles Chem. China's Adipic Acid Industry 2026 Analysis [EB/OL].
[7] Haili Chemical. China Adipic Acid Price Trend in 2026 [EB/OL].
[8] Shandong Yuhua / sdyshx. Overview of Recent Global Adipic Acid Industry Developments [EB/OL]. 2026.
[9] Huafon Chemical. Bio-based Adipic Acid and Zero-Carbon Nylon 66 Progress [EB/OL]. 2024-2026.

Column: Technical Primer / Industry Watch | Featured Product: Purified Terephthalic Acid (Purified Terephthalic Acid, PTA) | Downstream: Polyester Fiber (Polyester) / Bottle Chip / Film

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Why Polycarbonate / Epoxy Resin Can't Do Without Bisphenol A (BPA)? From Molecular Structure to the Industry Chain

Why Nylon 66 / Polyurethane Can't Do Without Adipic Acid (AA)? From Molecular Structure to the Industry Chain