Solubility separations

Added 112 grams sassafras oil. Shake for a couple of minutes. You get an orangish emulsion. Clears within 15 minutes forming two layers, bottom layer oil, top layer acetic acid, eugenol + the other solubles. Separated the oil from the others, washed the oil layer 2x with fresh C//-/2O. Weight after acetic acid water washes 101.5 (-10.5 grams). 

Determination of copper as copper(I) thiocyanate Discussion. This is an excellent method, since most thiocyanates of other metals are soluble. Separation may thus be effected from bismuth, cadmium, arsenic, antimony, tin, iron, nickel, cobalt, manganese, and zinc. The addition of 2-3 g of tartaric acid is desirable for the prevention of hydrolysis when bismuth, antimony, or tin is present. Excessive amounts of ammonium salts or of the thiocyanate precipitant should be absent, as should also oxidising agents the solution should only be slightly acidic, since the solubility of the precipitate increases with decreasing pH. Lead, mercury, the precious metals, selenium, and tellurium interfere and contaminate the precipitate. 

Arsenic(ni) and Arsenic(V) Thiosalts. Filter off the arsenic sulphides obtained and test their solubility separately in ammonium... 

Bismuth is the most strongly metallic element of the fifth group, yet its salts in aqueous solution undergo partial hydrolysis very readily. In presence of a considerable amount of free acid, the Bi+++ ion is capable of existence in solution but with decreasing quantities of acid the tendency to hydrolyze increases, and the basic salt of bismuth, which is only slightly soluble, separates ... 

Their syntheses are described above. Some stannanes have been modified to improve their physical (solubility/separation/reactivity) properties ° ° °", while others have been tailor-made to aid in chirality transfer and to effect enantioselective outcomes during free-radical chemistry . ... 

Resolution can be thought of as the converse of racemization (Section 2.4). One starts with a 50 50 mixture of both enantiomers and separates this mixture into the individual enantiomers. Of course, for some purposes one may only want one enantiomer, and recovery of the second enantiomer can be painstaking. Since enantiomers have identical properties, including solubility, separation of enantiomers by recrystallization is quite rare. It was, however, such a crystallization by Pasteur in 1848 that opened up the field of resolution. Pasteur s key observation was that two distinct but related types of crystal were obtained from an aqueous solution of the sodium ammonium salt of racemic tartaric acid. The two types of crystal were related as object and non-superimposable mirror image, and one type was identical to the dextrorotatory crystals of sodium ammonium tartrate obtained from (+)-tartaric acid, itself obtained as a by-product of wine-making. 

After defining method goals, the next step is to gather sample and analyte(s) information such as those listed in Table 8.1. This information is useful for the selection of appropriate sample preparation procedures as well as the initial detection and chromatographic modes. If critical data are not available (e.g., pKa, solubility), separate studies should be initiated as soon as possible. 

We will deal with the permeability in greatest detail, because it is the quantity of most direct interest in applications. In developing a more fundamental theoretical understanding of transport, however, it will be crucial to consider the diffusivity and the solubility separately. Many of the shortcomings of simple structure-property relationships for the permeability and selectivity may possibly be overcome by a more fundamental understanding, which may therefore also be useful in future refinements and practical applications of correlative schemes. 

Polymers have, like all solid materials, a limited solubility, but if the concentration becomes greater than the solubility, separation into liquid phases occurs, not precipitation. The factors governing this are briefly... 

As we related in the introduction to Appendix A, this patent should be read by everyone involved in research and process development using supercritical fluids. In his examples, Zosel describes results on neat solubility, separations of liquids and solids, fractionations, etc. A wealth of information is given on the performance of various gases, e.g., ethylene, ammonia, ethane, carbon dioxide, in dissolving a variety of compounds. Several interesting experiments carried out in a plexiglass autoclave are descrited, and certain phase separations are noted. Some of the information can be found in other references, of course, but not in such succinct form. It is of pedagogical value to reproduce one of the examples here. 

Several problems accompany the GC-MS technique. Initial problems are those associated with any gas chromatographic analysis since the quality of the mass spectra is limited by the degree of separation in the chromatograph. Water and soil extracts can be chromatographed directly sometimes, but prior cleaning by column chromatography or solubility separations is usually necessary for good mass spectra. Some pesticides decompose on the metal injection port or metal columns we have not been able to obtain a spectrum of endrin by the GC-MS technique for this reason. 

The selectivity experiments should characterize the manner in which the method is selective and examine other substances that might reasonably be expected to be detected, in addition to the target analyte(s). The selectivity can be characterized, in part, by understanding and documenting how the various steps in the method provide selectivity. For example, steps in the method may introduce selectivity through differences in solubility, separation based on polarity, the inclusion of a derivatization step that targets specific functional groups, or use of a detector that responds... 

Ions can be separated from each other based on the solubilities of their salts. Gsnsider a solution containing both Ag and Cu. If HCl is added to the solution, AgCl (K = 1.8 X 10 ) precipitates, while Cu remains in solution because CUCI2 is soluble. Separation of ions in an aqueous solution by using a reagent that forms a precipitate with one or more (but not all) of the ions is called selective precipitation. 

Recently for the first time substituted 1,2-naphthalocyaninatoiron-derivat-ives R4-l,2-NcFe(CNR )2 (R = t-bu, CgHj methyl, R = t-bu, alkyl) have been prepared and, due to their comparatively high solubility, separated by column chromatography. One of the isomers, substituted with four r-bu-groups in the ring, was shown to be a symmetrical isomer too by a crystal structure analysis [109a]. 

Layer out—a process in which two liquids that are not soluble separate naturally from each other (example oil and water). 

In reactions 9.90 and 9.91, the precursor is the di(trifluoro-methylsulfonyl)amido salt of the metal rather than a halide as in eqs. 9.88 and 9.89. If M3 is reacted with [BMpyr][N(S02CF3)2] (compare with eq. 9.90), the product is [BMpyr]4[Prl6][N(S02CF3)2] containing the octahedral ion and a non-coordinated [N(S02CF3)2] ion. Separation of products from ionic liquid solvents is facile if the product is insoluble (separation is by filtration or removal of the solvent by cannula). However, if the product is soluble, separation may be difficult since the low volatility of ionic liquids prevents their ready evaporation. If the product is volatile, it can be separated by distillation because the ionic liquid has such a low vapour pressure. 

Obtain elemental analysis of your product. Determine its m.p. Check its solubility separately in water and in organic solvents. Compare the solubility of this complex with the one prepared in Sec.4.6.1 above and comment on your observations. 

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