Solvent extraction vacuum drying

A mixture of 0.20 mol of the adduct from cyclooctene and dibromocarbene (note 1) and 250 ml of dry diethyl ether was cooled to -65°C. A solution of 0.23 mol of ethyllithium (note 2) in 200 ml of diethyl ether (see Chapter II, Exp. 1) was added in 15 min with cooling between -60 and -50°C. The reaction was very exothermic (note 3). After the addition the cooling bath was removed and the temperature was allowed to rise to about -10°C and the reaction mixture was poured into 200 ml of ice-water. The aqueous layer was extracted twice with diethyl ether. After drying, the solvent was removed in a water-pump vacuum and the remaining liquid was distilled through a 40-cm Vigreux column. 1,2-Cyclononadiene, b.p. 62°C/22 mmHg, 1.5059, was obtained in 86 yield. 

The hydrochloric extract is then made alkaline and the separated base is extracted with ether. After drying, the solvent is evaporated and the residue is distilled in the high vacuum, whereby the N-(3-dimethylamino propyD-imino dibenzyl passes over at a temperature of 160°C under 0.1 mm pressure. The chlorohydrate with a melting point of 174° to 175°C is obtained therefrom with alcoholic hydrochloric acid. 

Solvent extraction experiments were performed on all processed homopolymers and blends. The samples were first weighed then immersed in 20 mL acetone for 24 hours at room temperature. The remaining solid rod was removed from the acetone, vacuum dried and reweighed. The remaining experimentation was performed only on samples from (A) and (D) above. 

The p-tolylphosphine complex is prepared in a similar manner, except that its greater solubility in THF and diethyl ether precludes precipitation with diethyl ether. The product is isolated by removing the THF/diethyl ether reaction solvent under vacuum and extracting the residue with toluene (dried by distillation from sodium). The toluene extracts are filtered and diluted with an equal volume of hexane (dried by distillation from sodium). Upon slow cooling, fine red needles are deposited. 

Natural dyes processed for the market do not undergo any chemical operations. Those operations involved are purely physical, such as grinding, spray or vacuum drying, and water or solvent extractions. None of these operations create any great environmental problems. 

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. 

Subsequent to freeze stabilization, wet books can be thawed and air dried with or without interleaving or they can be vacuum dried in heated chambers (5). The moisture in frozen books can be sublimed by freeze drying (10) or removed by a vacuum/thaw/outgassing process (8), with microwave energy (6, 14), with dielectric energy (6), or by solvent extraction with or without vacuum assistance (5). 

Solvent Extraction/Vacuum Dry. It is the same procedure as above, but when water has been completely replaced by solvent, the books are placed in a vacuum chamber and brought back to their original weight by evaporating the solvent in a reduced pressure chamber. (Solvent extraction is out of the question for most modern books, which are usually printed with highly soluble (in solvents) offset printing ink.)... 

Solvent Extraction, Vacuum Drying. The same procedure as described in the solvent-extraction technique was used except that the... 

Freeze-thaw vacuum, inter leave-air, and solvent extraction processes offer the greatest potential in drying these types of coated- and uncoated-paper books after they have been wetted and frozen. The drained-air, vacuum-air cycle, vacuum, microwave, and dielectric drying processes work well on uncoated paper, but they fail to dry books containing this type of coated paper. Small and large units for freeze-thaw, vacuum drying have been used successfully to remove water from these frozen coated and uncoated books. 

Costus Root Oil occurs as a light yellow to brown, viscous liquid with a peculiar, persistent odor reminiscent of violet, orris, and vetivert. It is the volatile oil obtained by steam distillation from the dried, triturated roots of the herbaceous perennial plant Saussurea lappa Clarke (Fam. Compositae) or by a solvent extraction procedure followed by vacuum distillation of the resinoid extract. It is soluble in most fixed... 

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