Product Overview
Organic solvents Propylene Carbonate (abbreviated as PC), also known as 1,2-propanediol carbonate, is an important five-membered cyclic carbonate organic solvent with the molecular formula C₄H₆O₃. At ambient temperature, it is a colorless, odourless transparent liquid. Featuring a high boiling point, low melting point, high flash point, strong dissolving capacity, high dielectric constant and low volatility with low toxicity, it is hailed as a "green solvent".
Organic solvents Propylene carbonate is soluble in water and miscible with most organic solvents such as ethanol, ether, acetone, benzene and chloroform. It can dissolve numerous polymer materials and metal salts. Benefiting from its excellent physicochemical properties, it is widely applied in lithium-ion battery electrolyte solvents, industrial extraction and separation, gas purification, coatings and inks, daily-use chemicals and organic synthesis intermediates. It serves as a critical basic raw material within the modern green chemical and new-energy industrial chains.
Basic Parameters
|
Item |
Specification |
|
Chemical Name |
Propylene Carbonate (1,2-Propanediol Carbonate) |
|
CAS No. |
108-32-7 |
|
EINECS No. |
203-572-1 |
|
Molecular Formula |
C₄H₆O₃ |
|
Molecular Weight |
102.09 |
|
Appearance |
Colorless, odourless transparent liquid |
|
Melting Point |
Approx. −48.8 °C |
|
Boiling Point |
240～243 °C (at atmospheric pressure) |
|
Relative Density |
1.204～1.210 (20 °C) |
|
Flash Point |
Approx. 132 °C (closed-cup) |
|
Refractive Index |
1.421～1.422 (20 °C) |
|
Saturated Vapour Pressure |
Approx. 0.13 mmHg (20 °C) |
|
Solubility |
Soluble in water; miscible with organic solvents including ethanol, ether, acetone, benzene and chloroform |
|
Dielectric Constant |
Approx. 64 (25 °C); high polarity and strong dissolving power |
Production Processes
Cycloaddition of Propylene Oxide (PO) and CO₂
Principle. PO reacts with CO₂ over a catalyst to form propylene carbonate, with ideal 100% atom economy. The catalyst opens PO's three-membered ring, followed by CO₂ insertion and ring closure into a five-membered cyclic carbonate. Main side reactions: PO self-polymerization to polyethers, and copolymerization with CO₂ to poly(propylene carbonate) (PPC), which consumes feedstock and lowers PC yield.
Raw materials & catalyst. PO, industrial-grade CO₂; iodide–metal composite catalysts, supported ionic liquids, zinc/aluminium salts, halides and imidazolium ionic liquids.
Conditions. 120–160 °C, 2.0–5.0 MPa, 3–5 h. PO conversion 95–99%, PC selectivity >98%.
Flow.
Pretreat: dehydrate PO and dry CO₂ to prevent catalyst hydrolysis.
High-pressure stirred reaction; strongly exothermic, with circulating cooling.
Cool, depressurize and flash; recompress and recycle unreacted CO₂.
Separate catalyst, then vacuum-distill to remove residual PO and polyether oligomers.
Phosgene Process
Principle. Two-step route: 1,2-propanediol first reacts with phosgene (COCl₂) to form 2-hydroxypropyl chloroformate, then cyclizes intramolecularly with HCl elimination to PC. Overall: CH₃CH(OH)CH₂OH + COCl₂ → C₄H₆O₃ + 2HCl↑. By-products include polycarbonate oligomers and organochlorine impurities.
Raw materials & conditions. 1,2-propanediol, phosgene; 75–80 °C at atmospheric pressure; large HCl tail gas requiring alkali neutralization.
Flow. Feed propylene glycol, slowly add phosgene for acylation; absorb HCl tail gas as hydrochloric acid; heat to cyclize; alkaline-wash crude product to remove residual phosgene/HCl; phase-separate and vacuum-distill to finished PC.
Transesterification Process
Principle. Reversible acid/base-catalyzed transesterification of dimethyl carbonate (DMC) and 1,2-propanediol yields PC and methanol. Continuous methanol removal shifts equilibrium toward PC. Side reaction: high-molecular-weight polycarbonate oligomers.
Raw materials & catalyst. DMC, 1,2-propanediol; sodium methoxide, organotin (dibutyltin dilaurate), solid bases.
Conditions. 90–130 °C at atmospheric/reduced pressure; methanol distilled off during reaction. Single-pass propylene glycol conversion 70–80%; unreacted feedstock recycled.
Flow. Reactive distillation: distill methanol overhead to break equilibrium; neutralize homogeneous catalyst after reaction; sequentially recover methanol, DMC and propylene glycol; vacuum-distill bottom crude PC to product.
Process Comparison at a Glance
|
Route |
Main raw materials |
Conditions |
Key trade-off |
|
PO + CO₂ cycloaddition |
PO, CO₂ |
120–160 °C, 2.0–5.0 MPa |
Green, 100% atom economy; needs high pressure and active catalyst; risk of PPC by-product |
|
Phosgene |
1,2-propanediol, phosgene |
75–80 °C, atmospheric |
Mature but uses toxic phosgene; emits HCl and chlorinated impurities |
|
Transesterification |
DMC, 1,2-propanediol |
90–130 °C, atmospheric/reduced |
Mild conditions; equilibrium-limited (70–80% single pass), requires recycling |
Product Grades
|
Index |
Battery-grade |
Pharmaceutical-grade |
Industrial-grade |
Typical use |
|
Purity |
≥99.90% |
≥99.50% |
≥99.00% |
- |
|
PO residue |
≤0.0100% |
≤0.1000% |
≤0.2500% |
- |
|
Other key limits |
Water ≤10 ppm; single metal ion ≤1 ppm; total Cl ≤1 ppm |
Propylene glycol ≤0.0500%; strict heavy metals (Pb, As, Cd) and total Cl |
General water/glycol/fraction specs; metals and Cl not tightly restricted |
- |
|
Application |
Li-ion, power and energy-storage battery electrolytes; COA + SDS supplied |
Pharma intermediate synthesis and reaction solvent (not automatically excipient-grade) |
Extractants, plasticizers, industrial solvents, coating additives, fine chemicals |
- |
Upstream & Downstream Industry Chain
Upstream. Core feedstocks are PO and CO₂. PO cost and supply directly set PC pricing; PO capacity comes mainly from the chlorohydrin, co-oxidation and HPPO (hydrogen peroxide to PO) processes. CO₂ is mostly recovered from industrial units, fitting resource-recycling trends.
Downstream.
Li-ion electrolyte solvent – a key carbonate solvent for EV and energy-storage batteries; the main growth driver.
Green industrial solvent – extraction separation, gas desulfurization/decarbonization, coatings, inks and paint-stripping, replacing highly toxic VOC solvents.
Fine & daily chemicals – cosmetics, personal care, pharma intermediates, organic-synthesis carriers.
Others – plastic plasticization, adhesives, printing-dyeing auxiliaries.
Safety, Storage & Transportation
PC has low toxicity, low volatility and a high flash point; it is generally not classified as a hazardous chemical, though it is combustible.
Storage: cool, dry, ventilated dedicated warehouse; keep away from ignition/heat sources, strong oxidants, acids and bases; seal containers against moisture.
Fire protection: no open flames in storage zones; provide suitable fire-fighting equipment.
Operation: wear protective gloves and goggles, ensure ventilation; high-concentration vapours may irritate on prolonged exposure.
Transport: clean, sealed dedicated containers; ship as ordinary chemicals; prevent overturning, direct sunlight and moisture.
Frequently Asked Questions (FAQ)
Q: What are the core differences among industrial-grade, battery-/electronic-grade and pharmaceutical-grade propylene carbonate, and how to select the appropriate grade?
A: All three grades share identical molecular structure. Core distinctions lie in purity, water content and trace-impurity and metal-ion control precision. They are not interchangeable for different scenarios.
Industrial-grade PC: Cost-effective with baseline impurity compliance. Suitable for general-purpose solvents, extraction-separation, gas purification, coatings and inks and other conventional industrial scenarios.
Battery-/electronic-grade PC: Produced via ultra-deep purification; purity ≥ 99.9% with water and metal-ion contents at ppm-to-ppb levels. Exclusively for lithium-ion-battery electrolytes and high-end electronic-chemical high-precision applications.
Pharmaceutical/cosmetic-grade PC: Strictly controlled hygienic indicators and impurities, low irritation and high safety performance. Suitable for cosmetic formulations, personal-care products and pharmaceutical-intermediate scenarios.
Grade selection shall focus on purity, water content and metal-ion indices. Excessive water or metal ions in electrolyte applications will degrade battery performance and may trigger safety hazards. Downgraded substitution is prohibited for high-precision manufacturing scenarios.
Q: How to distinguish and select among propylene carbonate (PC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC)?
A: All four are common carbonate-based solvents for lithium-ion-battery electrolytes. Selection is based on molecular structure, dielectric constant, boiling point and low-temperature performance.
Propylene Carbonate (PC): Cyclic carbonate with high dielectric constant, strong lithium-salt dissolving capacity, high boiling point and low freezing point for good low-temperature performance; a key electrolyte component.
Dimethyl Carbonate (DMC), Ethyl Methyl Carbonate (EMC), Diethyl Carbonate (DEC): Linear carbonates with low viscosity and moderate volatility, improving electrolyte wettability and safety. Frequently formulated together with PC.
Selection follows electrolyte-formulation targets: Prefer PC when high dielectric performance, wide operating-temperature range and strong dissolving power are required. Introduce linear carbonates in proper ratios for low viscosity and rapid wetting. In practice, mixed formulations are widely adopted.
Q: What are the competitive advantages of China's propylene-carbonate industry?
A: Supported by mature and stable propylene-oxide-carbon-dioxide cycloaddition technology, China's propylene-carbonate industry features complete supporting industrial chains and world-leading production capacity. Its proven battery-grade deep-purification technology enables mass supply of full-range products covering industrial-grade, battery-/electronic-grade and pharmaceutical-grade grades. Products meet international standards while offering prominent cost advantages, satisfying critical market demand from China's lithium-battery new-energy and fine-chemical industries.
Shanghai Dingwujin Chemical Co., Ltd. leverages the large domestic propylene-carbonate market in China to develop chemical-product business targeting Central-Eastern Europe and Ukraine. Drawing on China's comprehensive chemical-industry resources, we have built a seven-dimensional value-added service system covering procurement, custom manufacturing, private-branding, packaging processing, green compliance, authoritative testing and long-term ESG risk management. We specialise in chemical-supply-chain planning, compliance-risk control and localised delivery, delivering professional chemical-industry solutions for customers in Central-Eastern Europe and Ukraine.
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