Experiment 4-steam Distillation r59

Name: Rhett Adrian C. Seduco

Date Performed: 27 February & 02 March 2017 Date Submitted: 06 March 2017

EXPERIMENT 4 STEAM DISTILLATION I. Summary of Results Table 4.1. Measured Masses and Percent Recovered Plant Used: Calamansi Scientific Name: Citrofortunella microcarpa Part of Plant Used: Rind

II. Discussion Essential oils are highly volatile substances isolated by a physical process from an odoriferous plant. They are mixtures of organic compounds that are dominated by the terpenes and the terpenoids, oxygen containing derivatives of the terpenes. The pleasant odor that we come across the fruits, flowers, stems, barks and roots of nearly all plants is actually due to the presence of these essential oils. The oils are formed in the green (chlorophyll-bearing) parts of the plant, and with plant maturity are transported to other tissues, particularly to the flowering shoots. Essential oils are found in the vegetable structures to which they give their characteristic odor and are intimately connected with the vital processes that take place in plants. Essential oils are used in a wide variety of consumer goods such as detergents, soaps, toilet products, cosmetics, pharmaceuticals, perfumes, confectionery food products, soft drinks, distilled alcoholic beverages (hard drinks) and insecticides.

The isolation of essential oils is sometimes accomplished by steam distillation. In this technique, compounds that are less volatile than water are co-distilled with water. This allows for distillation at temperatures lower than necessary to distill the oil by itself. High temperatures will often cause an organic compound to decompose. In this experiment, the essential oils from calamansi rind are steam distilled. Three different methods of steam distillation are practiced. In the oldest and simplest method a vessel containing water and the chopped or crushed plant material is heated by a direct flame, and the water vapor and volatile oil are recovered by a water-cooled condenser. This original method is being replaced by a process in which the plant material is suspended on a grid above the water level, and steam from a second vessel is introduced under the grid. The volatiles are condensed and the oil is separated. In the third process, the vessel containing the plant material on a grid is heated to prevent condensation of steam, so that dry distillation is attained. Citrus fruits include oranges, lemons, limes and grapefruits, in addition to tangerines and pomelos. Not only are the citrus fruits in this diverse group delicious and refreshing, they earn their definition of an all-star food for their richness in compounds called flavonoids, which have anticancer properties. The plants are characterized by winglike appendages on the leaf stalks, white or purplish flowers, and fruit (classified scientifically as a kind of berry) with a spongy or leathery rind and a juicy pulp divided in sections. The leaves, flowers, and rind of the fruit abound in volatile oil and emit a sharp fragrance. Attempting to distill these essential oils directly from the plant material is generally not feasible. In general, most of the oils' constituents are high boiling and will decompose under the high heat needed to bring them to a boil. Steam distillation is a much gentler method of achieving the same end. In steam distillation, the distilling pot is infused with steam, which carries the oil’s vapor into the distilling head and then into the condenser, where the oil and water co-condense. Steam distillation works because the water and the oil are immiscible. Hence, they boil independent of each other. So, boiling occurs when the sum of the pure vapor pressures equals the atmospheric pressure. Thus, a mixture of two immiscible liquids boils at a temperature lower than the normal boiling point or either component of the mixture. Because vapor pressure of water is greater than the vapor pressure of oil, the mixture will boil at a temperature slightly less than the normal boiling point of water. This means the oil will vaporize under very mild conditions. Steam distillation can allow distillation of organic materials at lower than normal temperatures. This is especially useful when substances are prone to decomposing under higher temperatures. In steam distillation process, it is observed that the total vapor pressure in the distilling flask had become higher since there was an addition of the water’s vapor pressure. So this means

that the mixture doesn’t have to apply more energy and pressure for it to fulfill the requirement for vaporization. Thus, the mixture with oil vaporized at a lower temperature. For instance, imagine that there is a mixture of immiscible liquids (both water-insoluble) that is subjected to steam distillation. At 90°C, the vapor pressure of pure water is 526 mmHg. If the vapor pressure of compound A is 127 mmHg and that of B is 246 mmHg at 90°C, the total vapor pressure of the mixture at 90°C is 899 mmHg since you are just going to add the vapor pressure of water, and compounds A and B. This mixture will boil at a temperature below 90°C. The boiling is the point at which the vapor pressure of the liquid is equal to that of the atm pressure. Since the BP is directly proportional to pressure, and that the atm pressure(760 mmHg) is less than the vapor pressure of the liquid (899 mmHg), the boiling point will be approximately 76.08 degrees Celsius. Doubling the amount of water used results to no noticeable effect of temperature on the vapor pressure and boiling temperature. In other words, steam distillation is a separation process used to purify or isolate temperature sensitive materials, like natural aromatic compounds. Steam or water is added to the distillation apparatus, lowering the boiling points of the compounds. The goal is to heat and separate the components at temperatures below their decomposition point. Steam distillation is a special type of distillation for temperature sensitive materials like natural aromatic compounds. Even though it become obsolete by vacuum distillation, still, it remains important in certain industrial sectors. In this experiment, calamansi is used as the plant raw material for essential oil production. Calamansi (Citrofortunella microcarpa) is a smooth and slightly spiny plant, growing to a height of 3 to 5 meters. Leaflets are elliptic to oblong-elliptic, 4 to 8 centimeters long. Petioles are very narrowly or scarcely winged, about 1 centimeter long. Flowers are axillary, solitary, rarely in pairs, white, and short-stalked. Fruit is yellow when ripe, nearly spherical, 2 to 3.5 centimeters diameter, 6- to 7-celled, and thin-skinned. The skin or peel is green to yellowish green or yellow, loosely adhering to the flesh. The flesh contains a few light orange seeds. Calamansi (spelled kalamansi in native Tagalog orthography) is a small, very round citrus fruit that’s ubiquitous in the Philippines. The fruits are often used when the thin rind is still green on the outside, and that is the color associated with it. In the Philippines, calamansi is often combined with soy sauce, the mixture of which is used as a marinade or dipping sauce. Some properties of calamansi are aromatic, antiseptic, antiphlogistic, carminative, deodorant, and refrigerant. Studies have suggested that it has antimicrobial, antianxiety, antidepressant, hepatoprotective, expectorant, antioxidant properties. There are several essential oils that can be seen in calamansi. But of all its essential oils limonene is well-known as it is mostly found in almost all citrus fruits. Limonene, C10H16, is a colorless liquid hydrocarbon classified as a cyclic terpene. It takes its name from the lemon, as

the rind of the lemon, like other citrus fruits, contains considerable amounts of this compound, which contributes to their odor.

III. Conclusion At the end of the experiment, the recovered essential oil of calamansi is found to be 0.5937 g. The percent recovered essential oil is calculated by dividing the mass of recovered essential oil (1.595 g) to the pre-weighed sample of calamansi rind (203.24 g) and multiplying their quotient to 100. Thus, the essential oil recovered is 0.29%. It is expected that the outcome of the mass of oil is very small because calamansi essential oil contained in the rind of calamansi is only at around ____% depending on the variety of calamansi used. One factor is the maturity of the fruit used and also the season the fruit was picked. Steam distillation was quite convenient for laboratory purposes because the set-up is quite simple and no hazardous solvents were used. In addition, in the extraction of the oil from the distillate, it could be more productive if organic solvent was used to dissolve the oil and distil it to remove the solvent but this requires more time and careful handling of solvents because organic solvents are quite toxic. In addition, grinding of the peelings to a more refined state would ease the oil extraction from the peelings.

IV. References Steam Distillation – Wikipedia. Retrieved from https://en.wikipedia.org/wiki/Steam_distillation Steam Distillation Definition in Chemistry. Retrieved from http://chemistry.about.com/od/chemistryglossary/g/Steam-Distillation-Definition.htm Kalamansi / Citrus microcarpa / Chinese orange / Gan: Philippine Medicinal Herbs / Alternative Medicine. Retrieved from http://www.stuartxchange.org/Kalamansi.html Sublimation and Steam Distillation | Bryle Kristiann Camarote - Academia.edu. Retrieved from http://www.academia.edu/12417198/Sublimation_and_Steam_Distillation Calamansi or Kalamansi: Philippine Lime / Citrus. Retrieved from Limonene – Wikipedia. https://en.wikipedia.org/wiki/Limonene http://tagaloglang.com/kalamansi/