Propylene carbonate (PC) is a high-boiling, polar, aprotic solvent that sits at the crossroads of several growth stories: electrification (lithium-ion and sodium-ion batteries), solvent substitution in paints and industrial cleaning, and performance roles in pharmaceuticals and personal care.
With market growth commonly modelled in the ~5–7% CAGR range through 2030–2034, PC benefits from three tailwinds: (1) regulatory pressure away from hazardous solvents and toward VOC-exempt options, (2) the expansion of battery and electronics supply chains, and (3) the push to valorise CO₂ in chemical manufacturing via epoxide–CO₂ cycloaddition.
This article unpacks the chemistry, properties, market dynamics, applications, formulation tips, regulatory context, and future outlook—plus a practical comparison with “competing” carbonate solvents such as ethylene carbonate (EC) and ethyl methyl carbonate (EMC).
What propylene carbonate is—and why formulators like it
Chemically, PC is a five-membered cyclic carbonate formed by combining propylene oxide with carbon dioxide in a 100% atom-efficient cycloaddition. The result is a clear, mobile liquid at room temperature with unusually useful attributes for formulators:
High polarity / high relative permittivity (dielectric constant ~65 at ~20 °C), enabling robust salt solvation and excellent dissolution power for polar and ionic species.
Low volatility / high boiling point (~242 °C) and high flash point (~116–130 °C, method-dependent), translating to slower evaporation and safer handling compared with many conventional solvents.
Moderate viscosity (≈2.5 mPa·s at 25 °C)—low enough for processability but high enough to moderate evaporation and flow.
Good water miscibility and broad solvency toward organics, inorganics, and polymers.
In practice, those features make PC a “bridge” solvent: it can carry ionic species (battery salts, catalysts), plasticise polymer systems, and stabilise emulsions or gels, while still behaving like a conventional organic solvent in mixers, reactors, and coating lines.
Production routes and sustainability profile
Industrial PC is predominantly produced by cycloaddition of CO₂ to propylene oxide (PO) over heterogeneous or homogeneous catalysts. This route is well-studied and notable for its 100% atom economy—no stoichiometric by-products—making PC a flagship example of CO₂ utilisation in bulk and specialty chemistry.
Catalyst innovations (e.g., metal oxides, ionic liquids, bifunctional bimetallics) continue to improve conversion, selectivity, and durability, while lowering energy intensity. Newer papers also explore continuous-flow designs and alternative feedstocks (e.g., bio-epoxides), supporting scope 3 decarbonisation narratives in downstream industries.
Regulatory signal: In the United States, PC is VOC-exempt at the federal level because of its negligible photochemical reactivity. That status underpins adoption in coatings, cleaners, and paint-removal formulations, especially as agencies restrict or phase out high-hazard solvents.
Physical data at a glance
Table 1. Core physicochemical properties (indicative values)
| Property | Propylene carbonate (PC) |
|---|---|
| Appearance | Clear, colourless liquid |
| Boiling point | ~241–243 °C |
| Melting point | ~−49 °C |
| Flash point (c.c.) | ~116–132 °C (method-dependent) |
| Density (20–25 °C) | ~1.20 g cm⁻³ |
| Dynamic viscosity (25 °C) | ~2.5 mPa·s |
| Relative permittivity (20 °C) | ~64–65 |
| Water miscibility | Miscible / highly soluble |
Values representative of current SDS and handbook ranges.
Market overview and supply dynamics
Size and growth. Across major analyst houses, the propylene carbonate market is typically sized in the hundreds of millions of US dollars, with growth forecasts clustered around ~5–7% CAGR through 2030–2034. Differences in total addressable market stem from whether reports include battery-grade vs industrial-grade material, packaging/derivative value, and whether sodium-ion and capacitor applications are counted within the “battery” bucket.
Regional lens. Asia-Pacific leads consumption and capacity, anchored by China, Japan, and South Korea’s battery and electronics ecosystems. North America and Europe see resilient demand from coatings, cleaners, and speciality chemical segments, with capacity debottlenecking tied to EV/battery projects and VOC-compliance shifts.
Feedstocks and resilience. PC supply is linked to propylene oxide (PO) availability and CO₂ capture/utilisation infrastructure. As PO capacity expands and CO₂-to-chemicals receives policy support, supply resilience improves. Edge cases—like PO outages or logistics crunches—can tighten PC briefly, but overall supply chains have shown adaptability, aided by multiple grades (industrial, electronic, battery) and packaging formats.
Regulatory tailwinds. Bans and restrictions on methylene chloride in consumer paint strippers (and tightening scrutiny for other high-hazard solvents) have buoyed demand for VOC-exempt, lower-toxicity alternatives such as PC in surface preparation, cleaning, and stripping.
Battery chemistry basics: where PC fits—and where it doesn’t
In lithium-ion cells with graphite anodes, PC’s high permittivity is excellent for salt dissociation, but early LIB work discovered that PC tends to co-intercalate into graphite, exfoliating the anode and degrading capacity. The industry response was to pivot to EC-rich blends for LIBs (EC forms a robust SEI on graphite) and to redeploy PC in other roles:
Low-temperature and wide-temperature blends: PC’s wide liquid range and high flash point can be leveraged with SEI-forming additives, protective anode coatings, or alternative anodes to expand the service window.
Sodium-ion batteries (SIBs): PC has found a more natural home in SIB electrolytes, especially with hard-carbon anodes, where co-intercalation issues are mitigated. Computational and experimental studies show favourable Na⁺ solvation in PC and EC/PC mixtures.
Electrolytic capacitors / LICs: PC remains widely used as a high-permittivity solvent in aluminium electrolytic capacitors and other electrochemical devices.
State of the art. Recent research explores interfacial engineering (e.g., additive cocktails, anode coatings, modified solvation structures, microemulsions) to reconcile PC with graphite, aiming for all-climate LIBs. While these are promising, production-scale adoption will hinge on cost, longevity, and abuse-tolerance metrics matching conventional EC-based systems.
Coatings, paint stripping, and industrial cleaning
In coatings, PC serves as a slow-evaporating tail solvent with excellent polymer solvency (PU, PVDF, PVF) and strong pigment wetting. Its VOC-exempt status (US) and high flash point make it attractive for formulating toward compliant, lower-odour systems. In paint strippers and industrial cleaners, PC brings low volatility, low odour, and powerful solvency; it is often blended with alcohols, esters, or peroxide activators to tune removal speed and rheology—without resorting to methylene chloride or NMP.
Formulation thought-starters:
Use PC to moderate evaporation and improve film formation in high-solids coatings.
Blend with a lower-viscosity cosolvent (e.g., a linear carbonate or alcohol) to maintain sprayability and reduce dry-time penalties.
In strippers, pair PC with benign activators and thickeners to enhance dwell and vertical cling; always validate substrate compatibility.
Pharmaceuticals and personal care
PC is used as a solvent / viscosity-reducing agent in cosmetics, with safety reviews reaffirming its acceptability in current use patterns when formulated to be non-irritating. In pharmaceuticals, PC appears as a processing solvent and, in select cases, as an excipient in topical or oral dosage forms where its polarity and stability help solubilise challenging actives. Its low odour and biodegradability make it appealing in dermal products and medical-device processing, subject to pharmacopeial and internal toxicology thresholds.
Gas processing, electronics, and other niches
Beyond batteries and coatings, PC’s high permittivity and stability see use in gas purification (physical solvent for CO₂ scrubbing where H₂S is not present), electronic materials processing, adhesives & sealants (isocyanate diluent, resin modifier), and foundry / clay gellant roles. As more electronics shift to cleaner production chemistries, electronic-grade PC demand is rising, with stricter specs for metals, moisture, and contaminants.
Choosing between PC, EC, EMC, and friends
Table 2. Carbonate-solvent quick comparison for electrochemical and coating use
| Solvent | Rel. permittivity (25–40 °C) | Viscosity (25 °C) | Boiling point | Notes / Typical role |
|---|---|---|---|---|
| PC (cyclic) | ~65 | ~2.5 mPa·s | ~242 °C | High polarity; great salt solvation; VOC-exempt (US); not ideal with graphite unless engineered; good in SIB, capacitors; excellent in coatings/cleaners as a slow-evaporating solvent |
| EC (cyclic) | ~90 (liquid above mp) | high; solid at RT (mp ~36–39 °C) | ~248 °C | SEI former for LIB graphite; typically used melted or as a component in blends (EC/EMC, EC/DMC) |
| EMC (linear) | ~3 | ~0.6–0.7 mPa·s | ~107 °C | Low viscosity, fast-drying cosolvent to lower blend viscosity and improve low-T conductivity |
| DMC/DEC (linear) | ~3 | ~0.6–0.8 mPa·s | 90–127 °C | Low viscosity, fast-evaporating; widely used to tune electrolyte and coating dry times |
Values are representative ranges from current handbooks and supplier data; exact numbers vary by method and temperature.
Market projection snapshot (illustrative)
Formulation & processing guidance (industrial context)
Batteries and electrochemistry
LIB (graphite): If considering PC for wide-temperature benefits, pair with SEI-forming additives (e.g., VC, FEC analogues where permitted), graphite coatings, or alternative anodes; validate against exfoliation risk, impedance rise, and gas evolution at relevant current densities and C-rates.
SIB (hard carbon): PC or EC/PC mixtures with Na salts (e.g., NaPF₆, NaClO₄) are mainstream; track solid–electrolyte interphase stability on repeated cycling and storage at 45–60 °C.
Capacitors: Use high-purity, low-moisture PC; control water to ppm levels to protect conductivity and foil corrosion.
Coatings, adhesives, and strippers
Use PC at 5–20 % as a tail solvent to improve flow/levelling and pigment dispersion; balance with lower-boiling cosolvents for dry time.
For paint strippers, design gel systems with PC + activator systems, selecting rheology modifiers that resist syneresis and maintain cling; check accelerated ageing and “lift time” across coating chemistries (alkyds, epoxies, 2K PU).
Pharma & personal care
Verify residual solvent limits and dermal tolerability in line with corporate toxicology and regional regulations; PC is typically for topical/dermal and process uses rather than parenteral.
In actives solubilisation, PC can reduce viscosity and improve clarity; always qualify extractables/leachables for device-adjacent uses.
EHS & regulatory landscape
VOC-exempt (US): PC is excluded from the federal VOC definition, facilitating compliant formulations in coatings and cleaners.
Paint-stripper policy: Consumer use of methylene chloride in paint strippers is banned in the US, with wider restrictions emerging—driving interest in PC-based alternatives.
Worker safety: Despite low volatility, PC is still a combustible liquid; implement standard solvent controls (local exhaust, splash protection, thermal management) and observe applicable SDS exposure guidance.
Cosmetics: Recent safety panel reviews reaffirm PC as safe in current cosmetic use when formulated to be non-irritating.
Quality grades and specifications
Commercial PC comes in industrial, electronic, and battery grades, differentiated by metal ion content, moisture, acidity, and UV-absorbing impurities. Battery-grade specifications can push water to <20–50 ppm and metals (Na, K, Fe, Cu) to sub-ppm levels. For coatings and cleaning, industrial grades typically suffice; for cosmetic/pharma, request cosmetic/pharma documentation and impurity profiles.
Application case studies (condensed)
1) High-solids polyurethane clearcoat
A refinish formulator swapped a portion of Oxsol-100/tBuAc with PC to reduce odour, improve flow on vertical panels, and remain within VOC caps. A small amount (≤10%) of PC increased open time and reduced orange peel, with no blushing under humid spraybooth conditions. Dry-to-sand time was retained by balancing with a lighter cosolvent.
2) Sodium-ion cylindrical cells (hard-carbon anode)
A pilot line adopted NaPF₆ in EC/PC (1:1) with additive package targeting stable SEI at 25–45 °C. Compared with an ether solvent attempt, the EC/PC blend delivered higher initial CE and better calendar stability at 40 °C, at the cost of slightly higher low-temperature impedance—managed through particle-size and electrolyte loading optimisation.
3) Consumer paint-stripper gel (methylene-chloride-free)
A DIY brand moved to PC-rich gels activated with benign oxidisers and thickened to 50–80 k cP. Field testing showed adequate blistering across common architectural coatings within 1–6 h dwell, with superior odour profile and reduced PPE burden versus legacy chlorinated products.
Risks, trade-offs, and how to manage them
LIB graphite compatibility: Unless specifically engineered, PC is not the default for LIB graphite due to co-intercalation/exfoliation risk. Use where anode chemistry or interphase engineering permits.
Dry-time penalties: PC’s low vapour pressure slows evaporation; balance with lower-boiling cosolvents and temperature/airflow control.
Moisture sensitivity in electrochemistry: Tight dry-room protocols are mandatory for battery-grade use.
Variability in “green” claims: VOC-exempt ≠ risk-free. Perform full life-cycle and exposure assessments; align with corporate sustainability frameworks and solvent selection guides.
Sourcing checklist
Grade alignment: Industrial vs electronic vs battery; specify water, metals, UV absorbance, acidity.
Compliance docs: VOC status (jurisdiction-specific), cosmetic safety statements where relevant, and REACH/TSCA registrations.
Supply assurance: Dual-source where possible; confirm PO origin, plant reliability, and logistics (drums, IBCs, bulk).
Change control: Lock in specs and batch analytics; for battery use, institute lot-to-lot certificate reviews and retention samples.
Outlook: PC’s next decade
As EVs and stationary storage scale, battery-grade carbonates will remain strategic. PC’s role in sodium-ion and capacitor segments should expand, while interfacial engineering may unlock more LIB niches. In coatings and cleaning, VOC-exempt and low-toxicity profiles continue to drive share gains. On the supply side, CO₂-to-PC process improvements—better catalysts, lower pressure, integrated capture—offer attractive decarbonisation narratives. Expect greater specification tightening and product differentiation (e.g., ultra-low metal, bio-attributed PC) as downstream customers raise performance and ESG bars.
Conclusion
Propylene carbonate combines performance (high polarity, thermal stability), processability (miscibility, moderate viscosity), and policy advantages (VOC-exempt in the US) in a single solvent. Its nuanced position in battery technology—constrained in conventional LIB graphite but strong in sodium-ion and capacitors—underscores the importance of an application-specific approach. In coatings, cleaning, pharma, and personal care, PC’s low odour, low volatility, and broad solvency enable compliant, high-performing formulations.
If you’re exploring a switch from legacy solvents, designing next-generation electrolytes, or qualifying grades for regulated markets, the most successful programmes start with clear grade targets, robust impurity controls, and early pilot trials that respect PC’s strengths and limitations.