Citral steam distillation

The identification of geraniol can be confirmed by its conversion into citral, Cj Hj O, its aldehyde, which has a very characteristic odour and yields well-defined crystalline derivatives. Five parts of the alcohol fraction are shaken with 2-5 parts of chromic acid and four parts of concentrated sulphuric acid dissolved in 100 parts of water. The mixture is warmed in the water-bath for a few minutes, when crude citral separates on the surface of the liquid. This is purified by steam distillation and conversion into its sulphonic acid compound in the... 

When the normal sodium bisulphite compound is dissolved in water and submitted to steam distillation, half of the citral passes over, the remainder being converted into the sodium salt of the so-called stable citraldihydrodisulfonic acid —... 

Litsea cubeba oil is produced by steam distillation of the fruits of Litsea cubeba C. H. Persoon (Lauraceae) growing in East Asia. It is a pale yellow liquid with a fresh odor, reminiscent of citral. 

Figure 5 shows the thermally induced hydrolytic degradation of citral (geranial and neral) into 2-methyl-2-hepten-6-one and acetaldehyde. It is similar to the reaction mechanism as proposed by Josephson and Lindsay (22, 23). The relatively higher amount of 2-methyl-2-hepten-6-one and the concomitant lower amount of geranial and neral in steam distilled oil confirmed again a previous report (24). 

PROP Main constituent is citral. From steam distillation of freshly cut and partially dried grasses of Cjmbopogon citratus (STAFF) znd Andropogon nardus var. ceriferus (Hack). Light-yellow to brown liquid Kght lemon odor. D 0.869-0.894, refr index 1.483. Sol in mineral oil, propylene glycol insol in water,... 

In the present experiment citral is isolated by steam distillation of lemongrass oil, which is used to make lemongrass tea, a popular drink in Mexico. The distillate contains 90% citral and 10% neral, the isomer about the 2,3-bond. Citral is used in a commercial synthesis of vitamin A. 

Steam distillation is thus a very gentle method for isolating citral. The distillation takes place below the boiling point of water. The distillate consists of a mixture of citral (and some neral) and water. It is isolated by shaking the mixture with ether. The citral dissolves in the ether, which is immiscible with water, and the two layers are separated. The ether is dried (it dissolves some water) and evaporated to leave citral. 

Definition Oil from steam distillation of grasses of Cymbopogon flexosus and Andropogon nardus, contg. citral... 

Definition Volatile oil from steam distillation of fresh Cymbopogon citratus grasses contg. mainly citral... 

STEAM DISTILLATION ISOLATION OF CITRAL FROM LEMON GRASS OIL... 

Citral is a chemically labile substance, and its isolation therefore presents a challenge. This task is simplified by the fact that citral, bp 229 °C (760 torr), is relatively volatile and has low solubility in water. These properties make it a suitable candidate for steam distillation, a technique that allows distillation of citral from crude lemon grass oil at a temperature below 100 °C, which is far below its normal boiling point. Neutral conditions are maintained in steam distillation, as is the partial exclusion of atmospheric oxygen, so the possibility of oxidation and/or polymerization of citral is minimized. 

Steam Distillation of Citral from Lemon Grass Oil... 

Purpose To isolate the natural product citral using the technique of steam distillation. 

Why was a steam distillation rather than a simple distillation performed in the isolation of citral from lemon grass oil ... 

Suppose that you are to steam-distill a sample of a natural product whose vapor pressure at 100 °C is known to be half that of citral. What consequence would this have on the amount of distillate required per mole of the natural product present ... 

It contains dipentene, 15 per cent, of linalol, and 1 per cent, of citral. II, Y. ZoJler hai examined the oil obtained hy steam distillation from the peel of Citrus d umana grown in the United States. Fle found it to have thr following characters —... 

The residue of the ether solution is fractionally distilled under a reduced pressure and the fraction is collected, which boils under a pres-sure of 12 mm. at a temperature of from 138° to 155° C., and from it the unattacked citral and unchanged acetone and volatile products of condensation are separated in a current of steam, which readily carries off these bodies. 

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