13. Diagrama Presión-Temperatura y Fluidos Supercríticos

Summary

This video explores supercritical fluid extraction, focusing on the use of carbon dioxide (CO₂) as a solvent. The advantages of CO₂ include its non-toxicity, ease of recovery, and environmental benefits. The video also discusses subcritical water extraction (SW), a more eco-friendly technique using water under high pressure and temperature. Both methods are compared for efficiency and cost-effectiveness, with the speaker highlighting the importance of understanding thermodynamic equilibrium to maximize extraction yields. The video concludes by encouraging further exploration and engagement with the content.

Takeaways

• 😀 CO₂ is a less toxic solvent compared to traditional solvents like chloroform, benzene, or hexane, making it safer for extraction processes.
• 😀 Supercritical CO₂ is efficient in separating from the extract, as it remains a gas at standard temperature and pressure, making extraction easier.
• 😀 CO₂ has high diffusivity and low surface tension, allowing it to penetrate barriers that other solvents may not be able to.
• 😀 Supercritical CO₂ is non-flammable, which makes it safer than organic solvents commonly used for extraction.
• 😀 CO₂ can be easily recovered and reused, reducing emissions and contributing less to the increase in atmospheric CO₂ concentration.
• 😀 Subcritical water extraction (SWE) uses water below its critical point, maintaining it as a liquid at high temperatures and pressures.
• 😀 SWE is more environmentally friendly than traditional solvent extraction, as it uses water and avoids the toxicity and flammability of organic solvents.
• 😀 SWE has shown high efficiency in extracting components from solid samples, such as antioxidants from microalgae and flavonoids from orange peel.
• 😀 The extraction method should be chosen based on the commercial value of the product, as supercritical extraction can be expensive due to high energy requirements.
• 😀 Mathematical modeling of thermodynamic equilibrium can help predict the maximum theoretical yield of a product in supercritical extraction, guiding process decisions.
• 😀 Real extraction processes may not reach the theoretical maximum yield due to inefficiencies, meaning actual extraction will often be less than the theoretical value.

Q & A

What are the main advantages of using supercritical CO2 as a solvent for extraction?

Supercritical CO2 has several advantages, including lower toxicity compared to traditional organic solvents like chloroform, benzene, and hexane. It is also easy to separate from the extracted product, is non-flammable, and is environmentally friendly as it can be easily recovered and reused, reducing atmospheric CO2 levels.

How does CO2 behave in its supercritical state and why is this important for extraction?

In its supercritical state, CO2 has properties that make it an effective solvent: it is highly diffusible, has low surface tension, and can penetrate barriers that other solvents cannot. These properties allow CO2 to extract compounds more efficiently and selectively.

What is subcritical water extraction (SWE), and how is it different from supercritical fluid extraction?

Subcritical water extraction (SWE) uses water heated to temperatures between 100°C and 374°C and subjected to high pressure. Unlike supercritical CO2, SWE does not exceed the critical point of water. This technique alters the properties of water, making it a more polar solvent, which enhances its ability to extract compounds without the risks of toxicity or flammability associated with organic solvents.

Why is subcritical water extraction considered more environmentally friendly compared to traditional organic solvent extractions?

Subcritical water extraction is more environmentally friendly because it uses water, a non-toxic and abundant solvent, rather than organic solvents that are flammable and toxic. This method does not generate harmful waste or contribute to air pollution like traditional solvent extractions.

What are the temperature and pressure conditions required for subcritical water extraction?

Subcritical water extraction requires water to be heated to temperatures between 100°C and 374°C while maintaining high pressure. This ensures the water remains in a liquid state despite the high temperatures, altering its polarity to facilitate the extraction of specific compounds.

What are some of the applications of subcritical water extraction (SWE)?

Subcritical water extraction has been used to extract antioxidants from microalgae and flavonoids from orange peel, among other compounds. It is particularly effective for extracting compounds from solid samples like plant material and microalgae.

What is the role of thermodynamic modeling in supercritical fluid extraction?

Thermodynamic modeling helps predict the maximum theoretical yield of a product from an extraction process. By modeling the equilibrium between solid material and supercritical fluid, one can estimate the amount of product that can be extracted under specific temperature and pressure conditions, guiding decisions about the viability of the extraction method.

How does thermodynamic equilibrium influence the efficiency of supercritical fluid extraction?

At thermodynamic equilibrium, the composition of the product in the supercritical phase remains constant. This equilibrium provides the maximum theoretical amount of product that can be extracted. However, in practical applications, real extraction processes may achieve lower yields due to factors like inefficiencies in the system and irreversibilities in the process.

Why might it be economically unfeasible to use supercritical CO2 extraction for products with low commercial value?

Supercritical CO2 extraction requires expensive equipment and energy to maintain the high pressure and temperature needed. For products with low commercial value, the cost of extraction may outweigh the benefits, making alternative extraction methods more economical.

What key considerations should be made before investing in supercritical fluid extraction equipment?

Before investing in supercritical fluid extraction equipment, it is important to evaluate the maximum theoretical yield of the product, the purity of the extract, the efficiency of the extraction and purification processes, and the costs associated with acquiring and operating the equipment. A balance must be struck between product value and the costs of the extraction process.