Question

organic chemistry lab

Questions Explain why the distillate from the distillation was turbid. (0.5 marks) Why anhydrous magnesium sulphate was used in this experiment? (0.5 marks) Discuss two other methods (other than distillation and solvent extraction] that could be used of extraction of essential oils. (0.5 marks) Do not answer briefly, make sure you provide enough details to score the full mark

ISOLATION OF NATURAL PRODUCTS: EUGENOL ( organic chemistry lab )

Answer 1

Ans-1: During the steam distillation of eugenol, it is co-distillated with water. The solubility of eugenol is very less in water hence it gives a turbid look of the distillate due to a heterogeneous mixture.

Ans-2: The anhydrous magnesium sulfate is used to remove absorb all the water from the distillate, because it is highly soluble in water and takes away all the water from the distillate and giving a clear eugenol oil free from water.

Ans-3: The other methods are as follows:

1. SUPER CRITICAL FLUID EXTRACTION USING LIQUID CARBON DIOXIDE:

In super critical extraction the liquid carbon dioxide is used as a solvent instead of hot water or steam. The supercritical extraction process operates at 95 to 100 ºF whereas steam distillation operates at temperatures between 140 to 212 ºF.

In steam distillation the essential oil composition might change due to temperature but in this process extract is very similar in chemical composition and properties to the original plant from which they are derived.

Process:

Pressurized carbon dioxide, the supercritical liquid form, is pumped into a chamber filled with plant matter and due to its liquid properties it functions like a solvent and extracts the oil from the plant matrix. The liquid having the extracted oil is then brought back to natural temperature and pressure. It is then evaporates and left the pure essential oil in the collector reservoir.

It is a non-toxic and do away the handling of toxic organic solvents.

2. COLD-PRESS EXTRACTION

It is also called Expression or Scarification and is used mainly for extraction of oils form the citrus peels.

Process:

The fruit peels are placed in a device that mechanically breaks or rupture the essential oil sacs present the underside of the rind. The essential oil and pigments run down into the device’s collection area. The whole fruit is pressed to squeeze out the juice and the oil. Alternatively the whole fruit is place in the device. The oil and juice that are produced, contains solids and liquid. It is centrifuged to separate solids from the liquids. The oil separates out from the liquid layer and is transferred into another container.