Distillation extraction apparatus

One design of the micro steam simultaneous distillation extraction apparatus is given in Figure G 1.2.1. Both sample and solvent flasks are heated to their boiling points. Vapors coming from the sample and solvent flasks (Figure Gl.2.1, G and F) are mixed in the... 

The diagram of the micro steam distillation-extraction apparatus is given. The recovery yield is given for test compounds. 

Diagrams of SDE under vacuum and solvent consideration are given. The reader can also consult the additional literature giving other details relative to the methodology i.e., the Chrompack user manual contains a drawing of themicro steam distillation extraction apparatus. 

As was mentioned earlier, distillation and subsequent solvent extraction remains popular in the aroma research area Q). In this method for aroma analysis, the Likens-Nickerson apparatus has been a standard for over 20 years (17, 18). The primary limitation of the Likens-Nickerson distillation/ extraction procedure has been its operation at reduced pressure. It is desirable to operate the system under vacuum in order to reduce the sample boiling point to minimize the formation of thermally induced artifacts. The fact that the solvent side of the distillation-extraction apparatus is also under vacuum makes it difficult to retain the solvent in the apparatus. Even modifications of the apparatus to include a dry ice/acetone condenser followed by a liquid nitrogen trap do not permit easy operation under vacuum. Problems arise in that the solvent or aqueous vapors reach the cryogenic traps, thereby eventually blocking the exit of the condenser. The need to minimize exposure of the sample to heat has resulted in the more frequent use of two step procedures. Very often, the sample is simply placed in a flash evaporator, a certain volume of distillate collected and the distillate is solvent extracted via either separatory funnel or a continuous extractor. In this manner, the distillation process and solvent choice are not conflicting processes. 

The sample is diluted with the 10-fold quantity of distilled water and extracted for several hours with dichloromethane or diethylether using a Simultaneous Distillation-Extraction Apparatus (SDE). The organic phase is dried and concentrated by solvent evaporation using a Vigreux column. The concentrated extract can be applied to GC-analysis. This method is applicable for solid, viscous or pasty extracts and flavouring compounds [4],... 

A micro version of the distillation extraction apparatus has been described by Godefroot t al, (2J). This apparatus uses heavier than water solvents, e.g., methylene chloride or carbon disulfide as the extractant. Because only one milliliter of solvent is used, no further concentration of solvent is required. The authors found 15 minutes distillation/extraction time sufficient for recovery of nonpolar compounds, e.g., mono and sesquiterpenes, while one hour was required for oxygenated and higher boiling compounds. This apparatus was evaluated by Nunez and Bemelmans (28) for low levels of aroma compounds in water. They reported that results were satisfactory for volatile levels greater than 1 ppm. 

Figure 11. Micro steam distillation-extraction apparatus.

Their approach is deceptively simple. They make use of micro simvdtaneous distillation-extraction apparatus to generate the solutions that they can in tmrn inject directly onto the column head of the gas chromatograph Their results can be used to demonstrate the versatility that characterises GC so well. Not only did the chromatograms so produced differed enough to allow them to... 

A more general purpose steam distillation/extraction apparatus is the steam codistillation extractor (SCDE) allows simultaneous condensation... 

Microversions of the distillation-extraction apparatus, described by Likens and Nickerson, have also been developed as well for high-density (Godefroot et al., 1981) and low-density solvents (Godefroot et al., 1982). The main advantage of these techniques is that no further enrichment by evaporation is required for subsequent gas chromatographic investigation. 

FIGURE 3.4 Distillation equipment used to isolate volatiles from foods (left high vacuum distillation of volatiles from an aqueous food right simultaneous distillation/extraction apparatus). (Reproduced from Guntert, M., G. Krammer, H. Sommer, P. Werkhoff, Flavor Analysis, C.J. Mussinan, M.J. Morello, Eds., Amer. Chem. Soc., Washington, D.C., 1998, p. 38. With... 

Initial Extraction Technique Continuous extraction apparatus was employed, including an extractor designed to contain the starting plant materials, a distillation flask to hold the solvent mixture, the flask being equipped with a reflux condenser, a drip device to facilitate the removal of the volatilized mixture from the condenser and to percolate it through the continuous extractor, and a Soxhiet type return. Means for heating the continuous extraction system were provided. 

After drying, the residue is treated in a Kumagawa extracting apparatus with boiling benzene. The benzene is evaporated and the residue is distilled in vacuo. About 50 g of cyanonerolin (BP = 205° to 208°C/14 mm) are obtained with a yield of about 70%. By recrystallization in 200 cc of methyl alcohol, 40 g of the product are obtained in absolutely pure state, in the shape of beautiful colorless needles (MP = 103°C with the Maquene block). By concentrating the mother liquor to half its original volume, a further 3.6 g of pure product are obtained. 

D. 2,3-Diamino pyridine (Note 12). In an apparatus for catalytic hydrogenation (Note 13) 56.4 g. (0.3 mole) of 2,3-diamino-5-bromopyridine suspended in 300 ml. of 4% sodium hydroxide solution is shaken with hydrogen in the presence of 1.0 g. of 5% palladized strontium carbonate (Note 14). When absorption of hydrogen is completed, the catalyst is removed by filtration, and, after saturation with potassium carbonate (about 330 g. is required), the resulting slushy mixture is extracted continuously with ether until all the precipitate completely disappears (usually about 18 hours, but this depends on the efficiency of the extraction apparatus). The ether is removed by distillation, and the residue of crude 2,3-diaminopyridine is recrystallized from benzene (about 600 ml. is required) using 3 g. of activated charcoal and filtering rapidly through a preheated Buchner funnel. The yield of 2,3-diaminopyridine, obtained as colorless needles, m.p. 115-116°, pKa 6.84, is 25.5-28.0 g. (78-86%) (Note 15). 

Seidel V, Lindner W. 1993. Universal sample enrichment technique for organochlorine pesticides in environmental and biological samples using a redesigned simultaneous steam distillation-solvent extraction apparatus. Anal Cem 65 3677-3683. 

It is very common to combine methods in obtaining aroma isolates. The simultaneous distillation/extraction method previously described is an example. Another popular combination method initially involves the solvent extraction of volatiles from a food and then high-vacuum distillation of the solvent/aroma extract to provide a fat-free aroma isolate. This technique is broadly used today to provide high-quality aroma extracts for numerous purposes. The apparatus used in solvent removal has been improved upon to reduce analysis time and efficiency the modified method is termed solvent-assisted flavour extraction (SAFE) [16]. 

Fat.—This may be determined on the dry residue from 2, which is placed in a filter-paper thimble in an extraction apparatus, white the dish is rinsed out with anhydrous ether or light petroleum into the extraction flask. The extraction is continued for about six hours, after which the bulk of the solvent is distilled off on water-bath, while the remaining... 

In a mortar containing a considerable amount of calcined coarse sand or pumice are placed 3-5 grams of the cheese, the whole being maintained for some hours in an oven at about ioo°, or better in a vacuum over sulphuric acid. The cheese is then well pounded with the sand and the mixture placed in a paper thimble and extracted with anhydrous ether in an extraction apparatus for 4 hours. The residue is subsequently pounded again and extracted anew for 2 hours with fresh ether. The united ethereal solutions are distilled and the residue dried for an hour at 100 0 and weighed. 

Heat under reflux for 4 hours a solution of 3 g (0.0165 mol) of undec-10-ynoic acid (Expt 5.23) in 240 ml of glacial acetic acid containing 13 ml of concentrated sulphuric acid and 1.4g of mercury(n) acetate. Dilute the dark coloured solution with 300 ml of water, filter and extract the solution with dichloromethane using a continuous extraction apparatus (Fig. 2.95) (1). Wash the dichloromethane extract carefully with distilled water until the washings are neutral, dry the extract and evaporate on a rotary evaporator. Recrystallise the solid residue from light petroleum (b.p. 60-80 °C) using a little decolourising charcoal. The yield of keto-acid, m.p. 56-57 °C, is 1.65 g (50%). 

Brenner KS. 1986. Pu-foam-plug technique and extractive co-distillation (Bleidner apparatus), versatile tools for stack emission sampling and sample preparation. Chemosphere 15 1917-1922. 

The resultant liquid is a mixture of immiscible oil and water, which separate out. Steam distillation is economical in processing large amounts of material, requiring little labour or complex extraction apparatus. A simple industrial steam distillation setup is shown in Figure 4.3. 

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