Extraction, advantages fractional

For use as an antioxidant, rosemary resin is usually fractionated from the essential oil because of the oil s strong eucalyptus-like note. This is a commercial process for CO2 extraction, but the extract has to compete commercially with solvent extraction of antioxidant, as the major advantage of capturing top notes that CO2 extraction has, is negated because of evaporation of the essential oil. A solvent extracted and fractionated antioxidant is as functional as a S.CO2 extract (reviewer s comment). 

Preparation of benzyl cyanide. Place 100 g. of powdered, technical sodium cyanide (97-98 per cent. NaCN) (CAUTION) and 90 ml. of water in a 1 litre round-bottomed flask provided with a reflux condenser. Warm on a water bath until the sodium cyanide dissolves. Add, by means of a separatory funnel fitted into the top of the condenser with a grooved cork, a solution of 200 g. (181-5 ml.) of benzyl chloride (Section IV.22) in 200 g. of rectified spirit during 30-45 minutes. Heat the mixture in a water bath for 4 hours, cool, and filter off the precipitated sodium chloride with suction wash with a little alcohol. Distil off as much as possible of the alcohol on a water bath (wrap the flask in a cloth) (Fig. II, 13, 3). Cool the residual liquid, filter if necessary, and separate the layer of crude benzyl cyanide. (Sometimes it is advantageous to extract the nitrile with ether or benzene.) Dry over a little anhydrous magnesium sulphate, and distil under diminished pressure from a Claisen flask, preferably with a fractionating side arm (Figs. II, 24, 2-5). Collect the benzyl cyanide at 102-103°/10 mm. The yield is 160 g. 

The principal components of the cut are butene-1, butene-2, isobutylene and butadiene-1,3. Methyl, ethyl, and vinyl acetylenes, butane and butadiene-1,2 are present in small quantities. Butadiene is recovered from the C4 fraction by extraction with cuprous ammonium acetate (CAA) solution, or by extractive distillation with aqueous acetonitrile (ACN). The former process is a liquid-liquid separation, and the latter a vapor-liquid separation. Both take advantage of differences in structure and reactivity of the various C4 components to bring about the desired separation. 

The advantages associated with the MAP technology as compared to conventional and automatic Soxhlet methods are considerable (Table 3.33). In MAP high sensitivity and selectivity by fractionation are achieved using different extraction media with similar, or better, linearity and reproducibility parameters. One of the principle features of the process is the lower temperatures observed in the microwave-extracted materials in contrast to volumetric heating usually experienced in traditional solvent procedures. These lower temperatures... 

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