Terpene Temperature Chart: Calculating the Boiling Point Under Vacuum
Principles of Distillation
The principle of distillation is based on separating components in a mixture by exploiting differences in their boiling points. This process involves heating a liquid mixture to create vapor and then condensing the vapor back into a liquid to achieve separation. Distillation is widely used in various industries, including chemical engineering, petrochemicals, food production, and perfumery, for purifying liquids, separating components, and recovering solvents.
Enthalpy
Enthalpy is the thermodynamic parameter that governs the phase change process at equilibrium. Expressed in energy units per mol, the enthalpy is a good measure of the energy needed to complete the phase change. The Clausius-Clapeyron equation describes the dependence of vapor pressures at two different temperatures given by the following equation:
- VP1 and VP2 are the vapor pressures at temperatures T1 and T2 , respectively.
- ΔHv is the enthalpy of vaporization.
- R is the gas constant.
Typically, the enthalpy is measured by measuring the boiling point at two different temperatures and pressures. The slope of the line is the enthalpy divided by the gas constant. Any reported enthalpy numbers must also take into account the range of the calibration.
Why do Terpene Boiling Points Matter?
Terpenes are volatile compounds, and their boiling points dictate the temperatures at which they evaporate. This directly impacts the flavor and aroma of various plants and their derived products. When heat is applied, such as vaporizing or distilling essential oils, terpenes with lower boiling points evaporate first, followed by those with higher boiling points.
Consider aromatherapy. Specific terpenes activate at different temperatures, releasing distinctive benefits and scents. A precise understanding of these thresholds enables practitioners to tailor their heat settings to achieve desired effects.
In the cannabis industry, knowledge of terpene boiling points boosts user experience customization. Connoisseurs adjust vaporizer temperatures to access varying terpene profiles, fine-tuning the balance between flavor intensity and psychoactive experience. This harmonization relies on understanding how terpenes interact at different stages of heating.
From a scientific perspective, terpene boiling points are critical parameters for quality control and product development. In the laboratory, precise temperature settings ensure accurate terpene extraction, leading to consistent product formulations with the intended therapeutic or flavor profiles. Profiling terpene content at different temperatures also provides valuable data for researchers studying plant compounds and their effects. Harnessing this knowledge is instrumental in honing product quality, whether for medical, recreational, or culinary purposes.
How to Preserve Terpenes
Preserving terpenes can drastically influence various plants’ flavor, fragrance, and therapeutic effects, particularly cannabis. Understanding terpene preservation fosters a better end-user experience and protects the natural essence of the source material. Below are several methods and considerations for optimizing terpene preservation.
Avoid Excessive Heat Exposure
Terpenes are sensitive to heat, with many reaching their boiling points at relatively low temperatures. This sensitivity calls for careful heat management. Storing products in a cool, dark place ensures that terpenes remain unaltered and that their properties are maintained. Avoiding direct sunlight and high temperatures will prevent the degradation of these compounds.
Control Environmental Factors
Environmental factors like air, humidity, and light can affect terpene stability. Ensuring an airtight environment reduces exposure to oxygen, which can oxidize terpenes, altering their potency. Humidity control is equally crucial, as high moisture levels can promote mold growth, compromising terpenes and the entire product. Desiccants or humidity control packs in storage containers could offer additional protection.
Gentle Processing Techniques
Different processing methods can impact terpene preservation. Techniques such as cold-pressing, CO2 extraction, and low-heat distillation have been developed to extract and distill terpenes efficiently without significant loss. These methods keep temperatures low enough to prevent boiling off the more volatile terpenes, retaining their profile and effectiveness.
Regular Monitoring and Testing
Regular monitoring of terpene profiles through testing can inform proper storage and handling procedures. One can adjust environmental conditions to uphold terpene integrity over time by continually assessing terpene levels. Advanced analytical techniques, such as mass spectrometry and high-performance liquid chromatography, offer comprehensive insights into terpene stability under various conditions.
Using the Terpene Temperature Chart and Calculator
This calculator will approximate how much you can expect the boiling point to decrease at a given vacuum level using known temperature and pressure data along with known enthalpies of vaporization. Remember that the vapor pressure is the sum of the individual Vapor pressures in the head space above the liquid. The numbers presented in the table are for pure substances in equilibrium. To use the calculator, refer to the terpene temperature chart below for the required inputs. The calculator will automatically deliver the new boiling point at a lower pressure.
The following chart details some of the key parameters that are needed to use the Clausius-clapeyron equation. Additional details for other compounds may be looked up in the NIST database:
| Terpenes | Boiling Point (K &°C) | Enthalpy of Vaporization (kJ/mol) | Pressure (mmHg) | Molecular Weight |
| Myrcene | 445K 172°C | 46 | 760 | 136.2 |
| Limonene | 451K 178°C | 45 | 760 | 136 |
| Linalool | 471K 198°C | 50 | 760 | 154 |
| Caryophyllene | 403K 130°C | 65 | 760 | 204 |
| Alpha-pinene | 430K 157°C | 45 | 760 | 136 |
| Geraniol | 503K 230°C | 63 | 750 | 154.2 |
| Isoprene | 307K 34°C | 26 | 750 | 68.1 |
| p-Cymene | 395K 122°C | 24 | 750 | 134.2 |
Some key points that need to be discussed in this table include the following:
- The enthalpies of vaporization are only validated for a small temperature range. The temperature ranges are given in the NIST database and can be easily looked up.
- If you prefer Celsius units, convert the boiling point from degrees Kelvin to degrees C by subtracting 273.1. The calculator uses Kelvin units.
Use Our Terpene Temperature Chart and Boiling Point Calculator
By taking the parameters in the above terpene temperature chart, you can use our vacuum boiling point calculator using the Clausius Claperyon Equation. Click below on the left to visit our calculator, and on the right to visit our calculator library, adjust the values to represent the boiling point you want to calculate, and input the pressure at which new boiling points will be calculated!
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