Diphenyl Oxide | Market Size, Share & Growth Report 2025-2033
The Diphenyl Oxide Market Report is Segmented by Product Type (Industrial Grade Diphenyl Oxide, Pharmaceutical Grade Diphenyl Oxide, Electronic Grade Diphenyl Oxide, Agricultural Grade Diphenyl Oxide, and Others), Application (Fragrances, Pharmaceuticals, Electronics, Agriculture, and Others), Distribution Channel (Direct Sales, Distributors, and Online Retail), Ingredient Type (Biphenyl, Benzene, Phenol, and Others).
Diphenyl Oxide Market
Market Analysis
How the market stands today, and what is shaping it
The global diphenyl oxide market was estimated at approximately USD 130.5 million in 2025, based on Core Market Research estimates. It is projected to reach around USD 187.0 million by 2033, representing a CAGR of approximately 4.60% from 2025 to 2033. The market covers industrial, pharmaceutical, electronic and agricultural grades supplied to heat transfer, fragrance, electronics and chemical synthesis uses through direct sales and industrial distribution. Growth rests on installations rather than on consumption, because diphenyl oxide is 73.5 percent of the eutectic thermal fluid sold as Dowtherm A, Therminol VP-1 and Diphyl, and each charge is fixed at that proportion. The principal constraint is service life: Eastman reports concentrated solar power plants from the mid-1980s still operating on their original maintained charge, so replacement demand is negligible. The leading producers hold around 60 percent of global share between them. Asia Pacific is the largest region, with East Asia at 22.1 percent in 2024 and a 10,000-tonne Chinese plant launched in the first quarter of 2025.
Market Dynamics
Key market dynamics and their impact on the industry landscape
Market Drivers
- Diphenyl oxide is the majority component of the thermal fluid that operates to 400 degrees Celsius in both vapour and liquid phase. The eutectic holds 73.5 percent diphenyl oxide against 26.5 percent biphenyl, so each charge of Dowtherm A, Therminol VP-1 or Diphyl carries that fixed proportion.
- The eutectic's stability from 12 to 400 degrees Celsius is what places it above mineral oils in process heating duty. A reaction requiring temperatures beyond the practical range of a mineral oil leaves few alternatives, which is why the composition has remained fixed across four decades and four competing brands rather than being reformulated.
- Concentrated solar power specifications treat the eutectic as the reference heat transfer fluid for parabolic trough designs. Because the fluid determines the achievable working temperature and therefore the plant's thermal efficiency, the material choice is settled at design stage rather than tendered separately once construction begins.
- Diphenyl oxide is inexpensive relative to the equipment it protects, which is what keeps it specified. A thermal fluid failure in a 400 degree Celsius circuit damages heat exchangers and reactors, so the fluid is bought on demonstrated thermal stability and supplier service rather than on delivered price per tonne.
- Jiangsu Zhongneng Chemical Technology Co. Ltd. launched a 10,000-tonne diphenyl oxide facility in the first quarter of 2025 for Chinese heat transfer fluid demand. Against a market Fact.MR measured at USD 124.8 million in 2024, a plant of that capacity represents a material addition to global supply rather than a marginal one.
Market Challenges
- The fluid outlasts the plants it serves. Eastman reports concentrated solar power installations from the mid-1980s still operating on their original maintained charge of the biphenyl and diphenyl oxide eutectic. Where a product has a forty-year service life, the installed inventory is large relative to annual production and replacement demand is negligible, so growth depends almost entirely on new installations.
- The market is small enough that one plant changes it. Fact.MR measured the global market at USD 124.8 million in 2024, while Jiangsu Zhongneng Chemical Technology launched a 10,000-tonne facility in the first quarter of 2025. Capacity additions at that scale relative to demand create the conditions for oversupply rather than for price recovery.
- Published estimates of this market differ by roughly sevenfold. Readings run from USD 124.8 million for 2024 to figures approaching USD 982 million for 2026. The lower family is internally consistent, since it reports North America at USD 15.9 million and the United States at USD 12.6 million, and those component figures cannot be reconciled with a global market approaching USD 1 billion.
- The composition is fixed at 73.5 percent diphenyl oxide and 26.5 percent biphenyl, which removes formulation as a route to differentiation. Dow, Eastman Chemical Company and BASF sell the same mixture as Dowtherm A, Therminol VP-1 and Diphyl respectively, so a customer switching brands changes supplier and service without changing the fluid in the circuit.
- Demand for the largest application is tied to a solar technology that has lost ground. Parabolic trough plants consume the eutectic in the largest single charges, but utility-scale solar capacity has been built predominantly as photovoltaic across North America and Latin America, which removes the installation pipeline that would otherwise carry volume growth.
Opportunities
- Chinese capacity could shift the market's supply geography rather than only its volume. The Jiangsu Zhongneng Chemical Technology facility launched in the first quarter of 2025 at 10,000 tonnes was built for domestic heat transfer fluid demand, which may reduce the region's dependence on imported material from the established brand owners.
- Regions with high direct normal irradiance may sustain trough construction where others do not. Morocco and the United Arab Emirates have built the largest parabolic trough capacity outside Spain and the United States, and a trough solar field is the single largest per-site consumer of the biphenyl and diphenyl oxide eutectic.
- Higher-purity grades could grow faster than the industrial bulk. Electronic grade diphenyl oxide commands a premium on purification cost rather than on chemistry, so a supplier able to hold tighter metallic and ionic specifications may capture value in applications where the industrial material is unusable.
- Fragrance use has potential to be more resilient than the thermal application. Diphenyl oxide's geranium-like odour and its stability at alkaline pH suit soap and detergent perfumery, a demand base that does not depend on new plant construction in the way heat transfer volume does.
- Process industries moving to higher reaction temperatures may widen the addressable duty. Because the eutectic operates stably from 12 to 400 degrees Celsius in both vapour and liquid phase, any process pushed beyond the practical range of mineral oils becomes a candidate application without requiring a new fluid to be developed.
Trends and Insights
Key market trends shaping the industry landscape
Production Capacity Localising In China
High impactShort-termChinese producers are adding diphenyl oxide capacity at home, with a 10,000-tonne plant from Jiangsu Zhongneng Chemical Technology Co. Ltd. entering service during the first quarter of 2025.
Insight: A market Fact.MR measured at USD 124.8 million in 2024 does not absorb a plant of that size without consequence. The addition points toward Chinese self-sufficiency in a material the established brand owners have supplied by export, which changes the competitive question from technology to landed cost.
Service Life Suppressing Replacement Demand
High impactLong-termEastman reports concentrated solar power plants commissioned in the mid-1980s still running on their original maintained charge of the biphenyl and diphenyl oxide eutectic.
Insight: Durability is a selling point for the fluid and a structural problem for the market. With a service life measured in decades, the installed inventory keeps growing while annual demand depends on new construction, so the ratio of stock to flow rises year by year.
Four Brands, One Fixed Composition
Medium impactLong-termThe 73.5 percent diphenyl oxide and 26.5 percent biphenyl eutectic is sold as Dowtherm A, Therminol VP-1, Diphyl, Thermex and VOT.
Insight: Where the specification is a eutectic point rather than a recipe, there is no product improvement available to a supplier. Competition therefore runs on supply assurance, technical service and the cost of qualifying a new source, which favours incumbency over innovation.
Demand Tied To A Retreating Solar Technology
Medium impactMid-termUtility-scale solar capacity across North America and Latin America has been built predominantly as photovoltaic rather than as parabolic trough.
Insight: The application that consumes this material in the largest single charges is losing the deployment pipeline that would carry it. Growth in the thermal fluid application is becoming concentrated in the few regions where direct normal irradiance still favours trough designs.
Liquid Form Carrying The Majority
Low impactMid-termFact.MR forecasts liquid diphenyl oxide at USD 105.3 million by 2034, or 57.1 percent of a USD 188.3 million market.
Insight: The physical form split tracks the application split rather than a customer preference, because the heat transfer use consumes liquid while the synthesis routes take solid flake. Form share is therefore a proxy for how much of this market is thermal fluid rather than chemical intermediate.
Segment Analysis
Market segmentation by product type, application, distribution channel, ingredient type
Grade in this market is a purity and specification distinction applied to one molecule rather than a set of different products. Industrial grade carries effectively all the volume, because the dominant use is as the major component of a heat transfer eutectic where trace impurities matter far less than thermal stability across the 12 to 400 degree Celsius range the fluid operates in. Electronic grade exists where diphenyl oxide is used as a solvent or intermediate in processes intolerant of metallic or ionic contamination, and it commands a premium on purification cost rather than on chemistry. Pharmaceutical and agricultural grades are intermediate specifications for onward synthesis rather than end products in their own right. Fact.MR forecasts liquid diphenyl oxide at USD 105.3 million by 2034, or 57.1 percent of the market, which is a physical form split cutting across these grades rather than a sixth category. No published figure allocates revenue across the grades themselves.
Geography Analysis
Regional market analysis
North America
North America accounted for USD 15.9 million of the USD 124.8 million global diphenyl oxide market in 2024, or roughly 13 percent, with the United States contributing USD 12.6 million, or 79.6 percent of the regional total. The region's significance exceeds its share because two of the three brands of the biphenyl and diphenyl oxide eutectic originate here: Dow sells Dowtherm A and Eastman Chemical Company sells Therminol VP-1, both reproducing the same 73.5 to 26.5 composition. Eastman reports concentrated solar power plants still running on their original maintained charge from the mid-1980s, which is a United States installed base that generates no replacement demand. Demand here is concentrated in chemical process heating rather than in solar thermal, because the region's utility-scale solar capacity has been built as photovoltaic rather than as parabolic trough.
Europe
Europe's position in this market rests on the third of the eutectic brands rather than on consumption volume, with BASF selling the mixture as Diphyl from a German base. No published figure reports European diphenyl oxide revenue on its own, and the regional breakdown available separates East Asia, North America, China and the United States without isolating Europe. The region's structural role is as a producer and specifier. The thermal fluid is used across European chemical processing where reaction temperatures exceed the practical range of mineral oils, and the eutectic's stability from 12 to 400 degrees Celsius is what makes it the default for those duties. Spain holds the largest European parabolic trough fleet, which is the application that consumes the fluid in the largest single volumes per installation. LyondellBasell Industries Holdings B.V., headquartered in the Netherlands, is a further European-domiciled participant.
Asia Pacific
Asia Pacific is both the largest and the fastest-growing region in this market. East Asia alone held 22.1 percent of the global diphenyl oxide market in 2024, and China accounted for USD 15.8 million of the USD 124.8 million total, marginally below the whole of North America at USD 15.9 million. The clearest evidence of direction is capacity rather than a growth rate: The first quarter of 2025 brought a 10,000-tonne plant from Jiangsu Zhongneng Chemical Technology Co. Ltd. on stream, built expressly for Chinese heat transfer fluid demand. No regional market size, revenue or growth figure was identified that would allow a regional rate to be measured for any region, so the growth ranking is a documented judgement rather than a measurement. China Petrochemical Corporation is among the named producers, which places upstream phenol and benzene supply inside the region alongside the conversion capacity.
Latin America
No published figure reports diphenyl oxide revenue for Latin America on its own, and the region does not appear in the breakdown that separates East Asia, North America, China and the United States. Its structural position rests on chemical process heating in Brazilian and Mexican industry rather than on solar thermal, because the region has built its utility-scale solar capacity as photovoltaic. Chile is the exception, since the Atacama Desert holds the solar resource that parabolic trough and tower plants require, and a trough installation is the single largest per-site consumer of the biphenyl and diphenyl oxide eutectic. Supply reaches the region through import rather than local manufacture, as none of the named producers operates diphenyl oxide capacity here. The regional position rests on installed process heating and solar resource rather than on a measured regional market size or growth figure.
Middle East & Africa
No published figure reports diphenyl oxide revenue for the Middle East and Africa on its own, but the region holds a concentration of the application that consumes the material in the largest single charges. Parabolic trough concentrated solar power requires the biphenyl and diphenyl oxide eutectic that Dowtherm A, Therminol VP-1 and Diphyl each reproduce, and the region's direct normal irradiance is what makes trough technology viable where it is not elsewhere. Morocco and the United Arab Emirates have built the largest trough capacity outside Spain and the United States. The constraint is that a solar field is filled once and then maintained rather than replenished, and Eastman reports plants from the mid-1980s still operating on their original charge, so a large installation converts into a single delivery rather than recurring demand. The regional position rests on solar resource and installed technology rather than on a measured market size.
Competitive Landscape
Key players and market positioning analysis
Competition in this market is unusual because the leading product has a composition fixed by physics rather than chosen by its suppliers. The eutectic of 73.5 percent diphenyl oxide and 26.5 percent biphenyl is a physical constant rather than a formulation, and it reaches customers as Dowtherm A from Dow, Therminol VP-1 from Eastman Chemical Company, Diphyl from BASF, and under the Thermex and VOT names. Four brands of one mixture means differentiation rests on supply assurance, technical service and the cost to a customer of requalifying a thermal circuit, not on product performance. BASF SE is named first among the leading manufacturers and combines its Diphyl position with upstream phenol and benzene integration, which matters in a market where the feedstock chain is the cost. Dow Inc. holds the original position, since Dowtherm A established the eutectic as the reference fluid for high-temperature duty, and it reaches smaller industrial buyers through distribution arrangements including ChemPoint rather than only through direct accounts. Eastman Chemical Company competes through Therminol VP-1 and has built its argument on demonstrated service life, reporting concentrated solar power plants from the mid-1980s still operating on their original maintained charge. China Petrochemical Corporation brings integrated petrochemical feedstock supply and a domestic demand base that reached USD 15.8 million in 2024, effectively level with the whole of North America. LyondellBasell Industries Holdings B.V. participates from a Netherlands base. The leading participants have been assessed as holding around 60 percent of global share between them, which makes this a moderately consolidated market. Jiangsu Zhongneng Chemical Technology Co. Ltd. is the entrant that matters most to the structure, having launched 10,000 tonnes of capacity in the first quarter of 2025 against a market measured at USD 124.8 million the year before. Several other companies appear in supplier listings without holding brand positions in the eutectic, including Sumitomo Chemical, SK Chemicals, Huntsman, Ineos, Shell and PetroChina.
Major Players
Leading companies in the market
Industry Developments
5 recorded developments
A 10,000-tonne diphenyl oxide plant from Jiangsu Zhongneng Chemical Technology Co. Ltd. came on stream in the first quarter of 2025, built for Chinese heat transfer fluid demand. Against a global market measured at USD 124.8 million in 2024, a single plant of that capacity is a substantial addition rather than an incremental one.
Fact.MR forecast liquid diphenyl oxide reaching USD 105.3 million by 2034, or 57.1 percent of the market, against a total of USD 188.3 million. The split matters because the liquid form is what the heat transfer application consumes, while solid flake is handled as an intermediate for onward synthesis.
Concentrated solar power plants commissioned in the mid-1980s continue to operate on their original maintained charge of the biphenyl and diphenyl oxide eutectic, as Eastman reports for its Therminol range. Service life of that length removes replacement demand from a market where the installed fluid inventory is large relative to annual production.
The same 73.5 percent diphenyl oxide and 26.5 percent biphenyl eutectic is sold under Dowtherm A by Dow, Therminol VP-1 by Eastman Chemical Company, Diphyl by BASF, and as Thermex and VOT. Four competing brands of one fixed-composition mixture means competition runs on supply reliability and service rather than on formulation.
Fact.MR put the global diphenyl oxide market at USD 124.8 million for 2024, with East Asia holding 22.1 percent of it, North America at USD 15.9 million and China at USD 15.8 million. The United States accounted for USD 12.6 million, or 79.6 percent of the North American total, which places the whole market at a scale one chemical plant can materially move.
Table of Contents
13 comprehensive chapters
1.1 Market Definition
1.2 Scope of the Study
1.3 Research Objectives
2.1 Research Approach
2.2 Data Sources
2.3 Market Estimation Approach
2.4 Forecast Assumptions
2.5 Research Limitations
3.1 Market Overview
3.2 Market Size and Forecast
3.3 Key Findings
3.4 Market Structure
4.1 Market Drivers
4.2 Market Challenges
4.3 Market Opportunities
4.4 Market Trends and Insights
5.1 Market Segmentation Overview
5.2 By Product Type
5.3 By Application
5.4 By Distribution Channel
5.5 By Ingredient Type
6.1 North America
6.2 Europe
6.3 Asia Pacific
6.4 Latin America
6.5 Middle East & Africa
6.6 Regional Market Comparison
7.1 Industry Developments
7.2 Industry Timeline
8.1 Market Structure and Competitive Positioning
8.2 Major Players
8.3 Strategic Developments
8.4 Key Competitive Factors
9.1 BASF SE
9.2 Dow Inc.
9.3 Eastman Chemical Company
9.4 China Petrochemical Corporation
9.5 LyondellBasell Industries Holdings B.V.
10.1 Market Size and Growth Outlook
10.2 Regional Market Outlook
10.3 Future Market Trends
10.4 Key Risks to the Forecast
11.1 Growth Opportunities
11.2 Key Risks and Constraints
11.3 Strategic Considerations
13.1 Glossary of Terms
13.2 Abbreviations
13.3 Research References
Scope of the Report
Report coverage and methodology
Study Period
Base Year: 2025
Forecast Period: 2025 - 2033
Geographic Scope
North America, Europe, Asia Pacific, Latin America, Middle East & Africa
Companies Covered
BASF SE, Dow Inc., Eastman Chemical Company, China Petrochemical Corporation + more
Data Sources
Primary research, industry interviews, regulatory filings, company reports
Frequently Asked Questions
Common questions about this report
Ready to Get the Full Report?
Access comprehensive market insights, detailed analysis, and strategic recommendations to make informed business decisions.