Carbon soxhlet extractors

Alkoxides (titanium ethoxide, titanium n-propoxide, titanium n-butoxide, titanium sec-butoxide, titanium ethylhexoxide, aluminum sec-butoxide, zirconium n-propoxide, and their mixtures), typically 3 ml, sonicated with propylene carbonate, typically 17 ml, for 20-30 to form uniformly turbid emulsions. Immediate addition of water (10 mol excess) hydrolyzed the alkoxides. Precipitated oxide powders washed (in a Soxhlet extractor) with THF or 2-propanol for 21-30 h, dried, calcinated... 

Liquid Carbon Dioxide Extraction. Mature ginger (Z. officinale Roscoe) rhizomes were obtained from a supplier in Hsinchu (Taiwan). The rhizomes were washed, sliced, freeze-dried, ground and sieved (200 mesh). About 110 g of freeze-dried ginger powder was placed in a glass Soxhlet extractor installed in a stainless steel liquid carbon dioxide extractor. Operating procedures were described previously (13). A golden brown oil material (3.44%) was obtained by the liquid carbon dioxide extraction. 

The used catalysts were washed with toluene in a Soxhlet extractor, stored in purified toluene and dried before analysis. C, H, S and N elemental analysis were performed by combustion using a Carlo Erba apparatus. The coke content is therefore defined in this work as being the carbon content of a used catalyst washed by hot toluene. Metal contents were measured by X-ray fluorescence spectroscopy. The coke hydrogen content was determined by difference between the hydrogen content measured for the used catalyst and the hydrogen content measured for the fresh NiMo catalyst (0.6 wt %). 

Procedure. A measured amount of water, optimum quantity 5000 gallons (18,925 liters), was pumped through a column of Nuchar C-190, 30-mesh activated carbon 3 inches in diameter by 18 inches in height. The pumping rate used was 0.5 gallon per minute. After collection, the carbon was removed from the filter, air-dried, and placed in a modified Soxhlet extractor to remove the organic matter by benzene. Except for 250 ml., all solvent was removed by distillation. The remaining solvent was further reduced to approximately 4 ml. by rotary vacuum evapora-... 

All carbons used in this research were pretreated to remove fines by sonication (Bransonic 220, Branson Cleaning Equipment) for 30 seconds followed by a rinse with Type I reagent-grade water (Millipore Corp). Coal-based carbons were then extracted with 2-N HCl in a soxhlet extractor for 42 hours to remove ash components and alkaline impurities. After extraction, the sample was boiled for four hours, then exhaustively rinsed until the pH of the suspension was in the range 5 to 6. All carbon samples were dried at 100 °C under vacuum, and stored in a vacuum desiccator. 

The support used was an activated carbon supplied by NORIT (SX+, 50-100 pm). It was oxidised by nitric acid as follows 6 g of SX+ was stirred in boiling 2.5 mol/L HNO3 (150 mL) during 24 h. After treatment, the carbon was removed by filtration and washed with distilled water on a Soxhlet extractor for 24 h, then dried under vacuum at 50°C for 4 h [5]. 

Diphosphorus tetraiodide (50 g, 88 mmol) was finely ground in a mortar, and extracted with 2.5 L dry carbon disulfide for 3 h in a Soxhlet extractor. Trans-1,2-diethynylcyclohexane-l,2-diol (10 g, 61 mmol) in 500 mL dry pyridine was added with... 

A sample is placed in a Soxhlet extractor and extracted for at least 6 hours using the following solvents 2-propanol, 2-butanone, hexane, methylene chloride, or perfluorinated carbon fluids. Solvent is then evaporated and the amonnt of extracted sirbstance determined by gravimetry. 

Samples were purified by extracting contaminants with toluene, carbon tetrachloride and n-hexane successively using a Soxhlet extractor. 

Dibenzoylnaphthalene introduced during 20 hrs. with the aid of a Soxhlet extractor into a refluxing soln. of LiAlH4 ether, then treated with Na-carbonate soln. l,8-bis(phenylhydroxym ihyi)i phthalene. Y 96%. R. L. Letsinger and P. T. Lansbury, Am. Soc. 81, 035 (1959). 

A commercial liquid carbon dioxide Soxhlet extractor is commercially available (J W Scientific, Folsom, CA). The vessel holds a sample of 2.5 g. 

Different plants including spearmint (Mentha spicata L ), rosemary (Rosmarinus officinalis L.), dill (Anethum graveolens L.), clary sage (Salvia sclarea L.) and chamomile (Matricaria chamomilla L.) were extracted with CO2 in a high pressure apparatus with 5 L extractor vessel volume. Fractionation of extracts was carried out by releasing the separation pressure at two stages. The extracts were separated into essential oil rich oil and fatty/waxy products. The extracts were collected as separate samples successively in time. The extraction with carbon dioxide was compared to conventional steam distillation (essential oils) and to Soxhlet extraction with hexane (fatty oils). 

Extraction of the plant materials was performed in a flow apparatus similar to that described in chapter 4. The current National Cancer Institute protocol for extracting new plant materials consists of Soxhlet extraction with 95% ethanol. (For comparison purposes a Soxhlet extraction was also done for this study.) Carbon dioxide conditions of 275 bar and 35°C were chosen to achieve a high density at a temperature reasonably close to ambient temperature. About 20 g of plant material were used for each extraction. The material was contacted with 200 standard liters of carbon dioxide in a flow extractor, and the extract that was collected when the carbon dioxide was expanded to ambient pressure was tested in a bioassay test. 

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