Melt extractor

The dry calcium malonate is placed in a 3-I. round-bottomed flask with sufficient (750-1000 cc.) alcohol-free ether (Note 3) to make a paste which can be stirred. The flask is surrounded by an ice bath, and the well-stirred salt is treated with 1 cc. of 12 N hydrochloric acid for each gram of salt. After the acid has been added slowly through a dropping funnel, the solution is transferred to a continuous extractor (Note 4) and extracted with ether until no more malonic acid is obtained. The product, as obtained from the undried ether solution by concentration, filtration, and drying in the air, melts at 130° or higher and is sufficiently pure for most purposes. The yield is 415-440 g. (77-82 per cent of the theoretical amount). 

The liquid is transferred to a continuous extractor (Note 10) and extracted with ether until the supernatant layer of ether remains colorless (about 2 hours). The ethereal extract is discarded (Note 11). The aqueous solution is transferred to a 1-1. beaker and acidified by the cautious addition of 60 ml. of 121V hydrochloric acid (Note 12). The solution is returned to the extractor, which is attached to a tared round-bottomed flask. The solution is extracted with ether until no more -hydroxyphenylpyruvic acid is obtained (Note 13). The undried ether solution is evaporated to dryness on a boiling water bath to give crude p-hydroxy-phenylpyruvic acid as a pale-yellow crystalline mass. The mass is broken up with a spatula, and the flask is kept over potassium hydroxide in a vacuum desiccator until its weight is constant. The yield of crude acid is 6.9-7.2 g. (92-96%). It melts at 210— 215° (dec.) (Note 14). 

Hollow fiber membrane(s), 70 766 76 1-31 additional types of, 76 24 advantages of, 76 3 categories of, 76 2-3 in desalination, 76 22 development of, 76 1 extractors, 70 787 fiber treatment for, 76 12-18 future prospects for, 76 26-28 glass and inorganic, 76 23-24 handling and unit assembly of, 76 15-18 interpenetrated wall matrix in, 76 15 low pressure, 76 24-26 macrovoids in, 76 12 materials associated with, 76 18-24 melt spinning of, 76 9-10... 

The solution is cooled to room temperature, saturated with sodium chloride (about 170 g. is required), and extracted with ether in a continuous extractor (Note 2). The extraction time is 15-20 hours. The ether extract is adjusted to a volume of 1 1., dried over 4-5 g. of sodium hydroxide pellets, and filtered, and the ether is removed by distillation from a steam bath. The residue crystallizes on cooling. The yield of dark red crystals melting at 61-63° is 39-41 g. (83-89%). 

The melt used in this work was prepared from the residue of hydrogen-donor extraction of Colstrip coal with tetralin solvent in such a way as to simulate the composition of an actual spent melt. The extraction was conducted in the continuous bench-scale unit previously described (17) at 412°C and 50 min residence time. The residue used was the solvent-free underflow from continuous settling (17) of the extractor effluent. The residue was then precarbonized to 675°C in a muffle furnace. The melts were blended to simulate the composition of a spent melt from the direct hydrocracking of the Colstrip coal by blending together in a melt pot zinc chloride, zinc sulfide, and ammonium chloride, ammonia, and the carbonized residue in appropriate proportions. Analysis of the feed melt used in this work is given in Table I. 

Carbamoyl-5-methylpyrazine 4-oxide (5.0 g) was added to 10% by weight sodium hydroxide (50 ml) and then refluxed for 30 min. The reaction mixture was acidified with dilute hydrochloric acid and extracted in a continuous extractor with ethyl acetate. The ethyl acetate extract was concentrated to small volume and gave, after filtration 2-carboxy-5-methylpyrazine 4-oxide (3.2 g), melting point 178°-180°C. 

The residue is extracted thoroughly with benzene in a large Soxhlet extractor (Note 3), and the benzene extract is evaporated to dryness. The crude product is dissolved in 50 cc. of hot water, the solution filtered, and the filtrate cooled in an ice bath with stirring (Note 4). The crystals are filtered with suction and dried in the air. The yield of slightly colored product melting at 94-95° is r5 r5.5 g. (40 4r per cent of the theoretical amount). 

The resulting white solid is washed first with sufficient dilute (10% by volume) acetic acid to dissolve the excess magnesium and then with water. The insoluble white powder, consisting of crude hexaphenyldigermane, is then dried (either in the air or by heating at 100 to 150° in an oven) and extracted with chloroform in a Soxhlet extractor. Filtration of the chloroform extract and concentration of the filtrate to 20 to 30 ml. gives a yield of pure hexaphenyldigermane of 18.3 g. (69%). The crystals melt at 346 to 347°. Anal. Calcd. for (C H6) Ge2 C, 71.1 H, 5.0 Ge, 23.9. Found C, 71.4 H, 5.0 Ge, 23.8. 

Although the density of the supercritical extractant is typically lower than that of the polymer, the column could as easily operate upside down, that is, if the density of the supercritical extractant was higher than that of the feed oil, the inlet positions of the respective streams shown in figure 9.2 would be reversed. Later in this chapter some phase and fractionation studies on an acrylate-ethylene copolymer with supercritical chlorodifluoromethane are presented. Over much of its active P-T range, supercritical chlorodifluoromethane is more dense than some of the polymers. Therefore, if that system were to be scaled to continuous operation at the commercial level, the liquid or melted polymer would be fed to the bottom of the extractor and chlorodifluoromethane to the top the subsequent fractions would be removed from the top of each separation vessel instead of from the bottom, as shown in the figure. In the polymers patent section of this book, we describe a process for polymer fractionation via stepwise pressure reduction exactly analogous to the process shown schematically in figure 9.2—the Hunter and Richards 1945 patent. 

In liquid extraction, sometimes called solvent extraction, a mixture of two components is treated by a solvent that preferentially dissolves one or more of the components in the mixture. The mixture so treated is called the raffinate and the solvent-rich phase is called the extract. The component transferred from raffinate to extract is the solute, and the eomponent left behind in the raffinate is the diluent. The solvent in the extract leaving the extractor is usually recovered and reused. In extraction of solids, or leaching, soluble material is dissolved from its mixture with an inert solid by means of a liquid solvent. The dissolved material, or solute, can then be recovered by crystallization or evaporation. Crystallization is used to obtain materials in attractive and uniform crystals of good purity, separating a solute from a melt or a solution and leaving impurities behind. 

Oxysanguinarine. One gram of sanguinarine nitrate in 200 cc. hot water is treated with a hot solution of 4 g. potassium ferricyanide and 2 g. potassium hydroxide in 100 CO. water. The mixture is then extracted with chloroform in a continuous extractor, the solvent removed from the extract, and the residue digested with 200 cc. 1% hydrochloric acid on the steam bath for 4 hours. The insoluble product (0.68 g.) is separated from the red-colored solution and purified by sublimation in a high vacuum. At 250-260° there is a forerun of unknown nature and the sought for compound subsequently sublimes at 290-310° in a yield of 74%. It is recrystallized from chloroform and then melts at 360-361° (corr.) when heated in an evacuated tube. 

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