Supercritical CO2 Extraction

What Is Supercritical CO2 Extraction?

Supercritical CO2 extraction is a process by which active components or desired compounds can be concentrated and purified from a feed material using pressurized CO2 above its critical temperature of 31°C. Subcritical CO2 extraction differs only from supercritical CO2 extraction in that the process is carried out below the critical temperature of CO2. The input feed material to a supercritical CO2 extraction process is often times a botanical or plant-based substrate that has a specific active component of interest. Alternately, the input feed to a supercritical CO2 extraction process can be a microbiological-based substrate, such as and algae or yeast or fungi, grown specifically to be rich in a component of commercial interest. Each type of substrate presents a different challenge to the supercritical CO2 extraction process and attention needs to be paid to the harvesting, drying, and milling of the substrate to achieve a high extraction efficiency for the active.

How Does the Supercritical CO2 Extraction Process Work?

To understand how a supercritical CO2 extraction process works, one must first understand what a supercritical fluid, and specifically supercritical CO2, is. A supercritical fluid can be explained best as follows: every compound has a critical point – the pressure and temperature at which its liquid and vapor phase become identical, and thus exhibits zero surface tension. This gas or liquid at pressure and temperature conditions that are above its critical point is termed a supercritical fluid (SCF). Every substance on earth exhibits a similar behavior as shown on the Pressure/Treatment diagram

The most prevalent gas used in supercritical fluid processing is CO2. Above its critical temperature and pressure, supercritical CO2 has substantial dissolving powers such that it can be used to solubilize many different compounds. In this manner supercritical CO2 can be used as a solvent replacement in a traditional solvent extraction process.

As an example and introduction to the dissolving powers of supercritical CO2 (and another gas, supercritical ethylene), the figure below shows the solubility of naphthalene in CO2(isotherm B) as a function of pressure.

As shown in Figure 1, at sufficiently high pressure, both solubility curves for the two gases asymptote at a relatively high level of 16wt% for supercritical ethylene (A), and about 8% for supercritical CO2 (B). It is not surprising that the solubility of naphthalene is different in the two supercritical fluids, just as one would expect different solubility levels for naphthalene in, say, hexane and ethanol.


Figure 1. Solubility of Naphthalene in Supercritical
CO2 (45°C) and Supercritical Ethylene (35°C)
Isotherm A = ethylene; Isotherm B = CO2

Supercritical CO2 Extraction Temperature and Pressure

The solubility of compounds can vary depending on the supercritical CO2 pressure and supercritical CO2 temperature being employed in the extraction process. Staying with the naphthalene example as the compound of interest to be extracted, the graph below shows the dependence of solubility for the supercritical CO2 pressure and supercritical CO2 temperature.

As an example and introduction to the dissolving powers of supercritical CO2 (and another gas, supercritical ethylene), the figure below shows the solubility of naphthalene in CO2(isotherm B) as a function of pressure.

Referring to the above chart, it is interesting to note the solubility of naphthalene in supercritical CO2 reaches a very high level of 10wt% at 300 atm and 50°C, and conversely exhibits a close to non-existence solubility of 0.1wt% at 70 atm and the same temperature of 50°C. This pressure-dependent solubility behavior of many different compounds in supercritical CO2 is one of the primary advantages of the supercritical CO2 extraction process.


Figure 2. Solubility of Naphthalene in CO2

Advantages of Supercritical CO2 Extraction

In any traditional solvent extraction process, and after the solvent has dissolved and removed the active component from the raw material matrix, there is a significant amount of infrastructure required to separate the desired extracted components from the solvent, and subsequent recycling of the solvent. In most cases the amount equipment and infrastructure required for solvent vaporization, distillation, and recycling far exceeds the equipment and infrastructure required for the pure extraction process. Also, the process to separate and recover the extracted components from the solvent, i.e., solvent vaporization, is typically an incomplete unit operation and will ultimately leave residual solvent levels remaining in the final product extract.

The pressure-dependent solubility behavior of supercritical CO2 can be taken advantage of in an industrial supercritical CO2 extraction process to provide an extract with no solvent residue and reduced equipment infrastructure as compared to the traditional solvent extraction process. Consider the two diagrams below.

a. Process Schematic


b. Solubility Map

The process schematic (a) shows a simplified industrial supercritical CO2 extraction process. With reference to the solubility map (b), supercritical CO2 at selected pressure-temperature conditions of 300atm, 55°C (Point 1) is passed through the extraction vessel that has been charged with naphthalene (in admixture with some other solid). As CO2 passes (percolates) through the vessel contents, naphthalene is dissolved to its solubility limit of 15 wt% and is extracted from the mixture. The supercritical solution (of CO2 and naphthalene) is passed through the pressure reduction valve and dropped in pressure to 90atm (due to thermodynamic phenomena the CO2 temperature drops to 35°C – Point 2). At 90atm, 35°C the solubility of naphthalene is only ~ 2%; therefore, more than 90% of the naphthalene “drops out like a snow” in the separator as it is no longer soluble in CO2 at these new conditions. The precipitated naphthalene remains in the separator as the CO2 gas steam exits to the compressor for re-use (recompressed) for further extraction. This cycle continuing until all the naphthalene is extracted from the vessel and precipitated in the separator.

This example described a process to extract naphthalene from a mixture. This same process can be applied to extracting an active compound from a botanical or plant-based matrix. The resulting extracted product will have no residual solvent as CO2, is not considered a volatile organic compound (VOC), and is a true gas in ambient pressure and temperature.

Overview of Advantages

Careful consideration of the supercritical CO2 extraction process results in understanding many advantages over traditional solvent extraction process. These advantages are listed and described below:

  1. No Solvent Residue: As explained above in our supercritical CO2 extraction process description, there remains no solvent residue in the final extracted product.
  2. Organic Certifiable Process: Supercritical CO2 extraction can be considered an organic process. Using synthetic, petroleum-based, and non-natural traditional solvents in an extraction process will disqualify the resulting final product extract from being able to be certified USDA organic. An extraction process using only CO2 will not prohibit the final product from being certified USDA Organic.
  3. Superior Product: The mild extraction temperatures used to collect the product in a supercritical CO2 extraction process as compared to the high temperatures used in distillation and solvent vaporization processes may lead to superior and more robust flavor profiles and full-spectrum final product extracts.
  4. Environmentally Conscious Process: The CO2 used in a supercritical CO2 extraction process is captured from natural fermentation processes. No CO2 is generated during the extraction process and much of the CO2 gas is used in recycle mode to reduce CO2 emissions to the atmosphere. There is no net gain of CO2 from the extraction process—it is a carbon neutral process. CO2 extraction processes can replace petroleum-based solvent extraction processes, and thus, significantly reduce the carbon footprint required to generate those petroleum-based solvents.
  5. Flammability/Hazardous – Safety Concerns: CO2 is a non-flammable and non-hazardous gas. Moving to a supercritical CO2 extraction process eliminates any flammability concerns and employs the use of a non-hazardous extracting medium. All petroleum-based solvents are flammable, and most are considered hazardous materials. For this reason, the spent biomass from a supercritical CO2 extraction process can typically be considered non-hazardous material ready for solid landfill waste or some other green agricultural end use, whereas, those spent biomasses from a petroleum-based solvent extraction process must go through rigorous de-solventizaton processes otherwise be categorized as hazardous materials

Supercritical CO2 Extraction Applications: Natural Products

A common application of the advanced supercritical CO2 extraction method is with the extraction of natural products. Specific to natural products extractions, here is an overview of the process and benefits customers can expect.


  1. Supercritical CO2 extraction involves the use of carbon dioxide in its supercritical state as a solvent. In this state, CO2 exhibits both liquid and gas-like properties, making it an excellent choice for extraction.
  2. The process begins by placing the natural product, such as herbs, plants, or botanicals, into an extraction chamber.
  3. Carbon dioxide is then pumped into the chamber under high pressure and temperature, causing it to reach a supercritical state.
  4. The supercritical CO2 interacts with the natural product, dissolving the desired compounds.
  5. The CO2 and extracted compounds are then passed into a separator, where pressure is lowered, allowing the CO2 to evaporate and separate from the extracted product.
  6. The final product obtained after the CO2 evaporation is a pure and concentrated extract, free from any residual solvents.


Enhanced Extraction Efficiency

  • Supercritical CO2 extraction offers higher extraction efficiency compared to conventional methods. It can selectively target and extract specific compounds, leaving behind unwanted impurities.
  • The control over pressure and temperature in this method allows for the precise extraction of desired components, minimizing the loss of volatile compounds.

Purity and Safety

  • Supercritical CO2 extraction is a completely solvent-free process. Unlike traditional solvent-based methods, there is no risk of residue from solvents contaminating the final extract.
  • The end product is pure and free from any harsh chemicals, ensuring the safety and quality of the extract.

Environmentally Friendly

  • Carbon dioxide used in the process is a natural and non-toxic substance. It is abundant in the atmosphere and can be easily recycled, making it an environmentally friendly choice.
  • Unlike other extraction methods, supercritical CO2 extraction does not contribute to air pollution or water contamination.


  • Supercritical CO2 extraction is versatile and can be applied to a wide range of natural products. It is commonly used for extracting essential oils, flavors, fragrances, herbal extracts, and cannabinoids from cannabis.
  • The process allows for customization based on the desired outcome, such as adjusting pressure and temperature to target specific compounds.

Supercritical CO2 extraction offers a superior and sustainable method of extracting natural products. Its efficient extraction, purity, and environmental friendliness make it highly beneficial for both prospective and existing customers. This method can meet your extraction needs and deliver high-quality extracts for various applications.

Phasex processes a variety of natural product extracts that are used in diverse applications, some of which include:

  • Nutraceutical ingredients
  • Dietary supplements
  • Topical or cosmetic ingredients
  • Health supplements
  • Food and beverage ingredients
  • Pet food ingredients
  • Flavor concentration
  • Hemp extracts/CBD ingredients

Supercritical fluids are widely preferred for extraction, purification, recrystallization, and fractionation operations in many industries. Phasex has run thousands of toll processing projects in over four decades—many of those for natural products. This technology is used to process hundreds of millions of pounds of coffee, tea, and hops annually. Supercritical CO2 extraction is also gaining in herbal and botanical extracts, vitamins, and supplements industries—the fastest growing segments of the food industry today—as it is synonymous with the highest purity and quality.

Increasing scrutiny of organic solvents and the demand for improved nutraceutical and natural products have led to the evaluation of alternative and improved extraction methods. Supercritical CO2 concentrate active compounds: astaxanthin from a from microalgae, paclitaxel from yew needles, lycopene from tomato skins, terpenes form cilantro, and also from whole plant hemp biomass. We can fractionate EPA/DHA from fish oils and algae, helping nutraceutical companies to provide healthy fat ratios, as well, essential oils from cedarwood and wormwood. Supercritical CO2 extraction is the most efficient separation method for the dietary supplements market; it is capable of providing the highest purities and concentrations attainable. Higher extraction efficiencies increase product concentration and yield, and most important, these superior quality extracts are free of solvent residues.

Phasex’s proprietary extraction process helps maximize your product yields, minimize your contamination, and ensure the highest purity and quality with supercritical fluids.

Supercritical Fluid Chromatography: Process and Importance of Selectivity

Supercritical fluid chromatography (SFC) is a separation technique that uses supercritical fluids as the mobile phase in the chromatographic process. We’ll discuss the process of SFC and why selectivity of particular substances is important and possible.


  1. SFC involves a stationary phase made up of a packed column, usually filled with a highly polar material.
  2. The mobile phase is a supercritical fluid (Phasex uses CO2 ), which is pumped into the column.
  3. The sample is introduced into the mobile phase, and the supercritical fluid carrying the sample is passed through the stationary phase of the column.
  4. As the compounds in the sample interact with the highly polar stationary phase, the various components are separated based on their physiochemical properties.
  5. The elution process is monitored by a detector, and the data are analyzed to produce a chromatogram.

Importance of Selectivity

  • Selectivity is the ability of SFC to separate two or more components from a complex mixture or sample based on their unique physiochemical properties.
  • The selectivity, or specificity, of an SFC method is highly important, as it determines how well the components of a mixture can be separated and identified.
  • By selecting a suitable stationary phase and mobile phase, the SFC method can have high selectivity and be tailored to separate target compounds precisely.
  • Selectivity is essential, as it helps to improve detection limits, reduce the time to analyze complex mixtures, and provide better resolution between the various components in a sample.
  • Selectivity is also utilized in preparative SFC, where the separated components of a comprehensive mixture can be isolated and recovered through various collection techniques such as trapping, fractionation, or recycling, thereby enhancing product yield.

Supercritical fluid chromatography is a versatile and powerful separation technique that can be used for a wide range of applications. The process involves the use of a stationary phase and a supercritical fluid mobile phase, which enables highly selective separation to occur. By selecting a suitable stationary phase and mobile phase and optimizing operating parameters, such as temperature and pressure, SFC can produce high-quality separations and be applied in the analysis and recovery of complex mixtures.

Markets Served

Natural Products Extracts

Customers in the natural products extract market rely on Phasex to:

  • Reduce or eliminate the harsh and toxic solvents currently used in typical extractions
  • Run certified-USDA organic toll processing services
  • Develop technically superior final products in a more environmentally conscious manner
  • Solve unique extraction, purification/remediation, and separation challenges

We process a variety of natural product extracts that are used in diverse applications, some of which include:

Customers in the natural products extract market rely on Phasex to:

  • Nutraceutical Ingredients
  • Dietary Supplements
  • Topical or Cosmetic Ingredients
  • Health Supplements
  • Food and Beverage Ingredients
  • Pet Food Ingredients
  • Flavor Concentration
  • Hemp extracts/CBD ingredients


Supercritical fluids extract toxic residues and residual monomers for the purification of medical products. Established medical and biopharma companies that require the most stringent purity levels in their devices for exacting processes trust Phasex’s proprietary supercritical CO2 extraction technology for the purification of medical products that also preserves the integrity of their products.


Supercritical CO2 fluid extraction is an environmentally conscious method to process polymers. CO2 processing for purification, fractionation, and polymerization applications is a green solution replacing various organic solvents used in industrial operations.

Supercritical fluid technology has proven success in the following industrial applications:

  • Purification of oils and greases
  • Polymer fractionation by MW and structure
  • Purification of polymers and reactive monomers and residual oligomers and color bodies

Phasex Services

Feasibility Studies: Companies are often hesitant to outsource innovation and product improvement, especially a long-term project, without first learning the potential for success. Understanding this need, Phasex carries out short, fast-response feasibility studies to demonstrate that processing with supercritical fluids can achieve desired goals, both technically and economically.

Click here to learn more about feasibility studies with Phasex.

Contract R&D: Supercritical fluid research programs conducted at Phasex are tailored to meet each customer's specific needs and can include:

  • Phase behavior studies using fixed and/or variable volume view cells rated for operation up to 6,000 and 12,000psi, respectively
  • Feasibility studies using one of a dozen interchangeable extraction modules ranging in size from 1L to 10L
  • Process development and optimization, including production of multi-kilogram quantities
  • Economic assessment and generation of a process flow diagram

Click here for more information about Phasex's R&D program.

Toll Processing: The toll processing facilities at Phasex are the most versatile and scalable in the U.S. We have four operational suites (with capacity additions underway). Each suite has two vessels; the size of each vessel in the suites range from 200 to 400 liters.

Manufacturing campaigns are carried out for many markets and applications, including the natural products, CBD ingredients/hemp extract, medical/biopharma, and industrial/polymers sectors.

Phasex’s proprietary food-grade supercritical CO2 extraction process helps:

  • Ensure the highest purity and quality of extracts with supercritical CO2
  • Minimize contamination
  • Maximize product yields
  • Retain potency in the final extracted ingredient
  • Maintain maximum product stability

Technology Licensing: Having pioneered supercritical fluids in a wide range of applications and having demonstrated the ability to create intellectual property, either as trade secrets or patents, we are frequently requested to develop technology for supercritical separations to be carried out as a part of a company's own manufacturing train. Our breadth and diversity of experience, our versatile facilities, and our unparalleled history of innovation make us the ideal partner for technology development and licensing.

Feasibility Studies: Companies are often hesita

Why Phasex

Gain access to four decades of proprietary extraction expertise when partnering with Phasex, the world’s most experienced supercritical fluid (“SCF” or “SC”) CO2 technology company, having performed thousands of feasibility studies and toll processing projects.

Processing with the Phasex Advantage

  • R&D contract work
  • Feasibility assessment for new products
  • Pilot scale-up
  • Minimize process/product optimization costs
  • Eliminate high-risk, early-stage capital investment
  • Produce improved products for test market
  • Accelerate speed to market
  • Full production with reserved capacity
  • Utilize Phasex knowledge and experience vs hiring your own staf

We’re here to provide the exact professional supercritical fluid CO2 extraction guidance you need in. What can we do for you?
Contact us today to begin the conversation.