Solvents solubility testing

Although SCMKA2 exhibited a single peak on moving boundary electrophoresis, it was shown to be heterogeneous by a constant solvent solubility test (Gillespie, 1957), by fractional precipitation with (NH4)2S04, and by... 

Group I. This includes the lower members of the various homologous series (4-5 atoms in a normal chain) that contain oxygen and/or nitrogen in their structures they are soluble iu water because of their low carbon content. If the compound is soluble in both water and ether, it would also be soluble in other solvents so that further solubility tests are generally unnecessary the test with sodium bicarbonate solution should, however, be performed (see Section XI,6). 

Polymer-solvent interactions and solubility testing were summarised by Staal [26]. 

Well, that just about concludes our brief look at solvents. If you can t dissolve it in one of the common solvents, you ve got problems. If in doubt, try a bit first, before committing your entire sample. Use nondeuterated solvents for solubility testing if possible, as they are much cheaper. 

The microautoclave solvent activity tests measure coal conversion in a small batch reactor under carefully controlled conditions. The tests are described as Kinetic, Equilibrium and SRT. The Kinetic and Equilibrium Tests measure coal conversion to tetrahydrofuran solubles at conditions where conversion should be monotonically related to hydrogen transfer. The Kinetic Test is performed at 399°C for 10 minutes at an 8 to 1 solvent to coal ratio. The combination of high solvent ratio and low time provide a measure of performance at essentially constant solvent composition. The measured conversion is thus related to the rate of hydrogen donation from solvent of roughly a single composition. In contrast, the Equilibrium Test is performed at 399°C for 30 minutes at a 2 to 1 solvent to coal ratio. At these conditions, hydrogen donors can be substantially depleted. Thus performance is related to hydrogen donor... 

Autoclave Results - Solvent Activity Test. The initial microautoclave work was done with tetralin and methylnaphtha-lene, using Indiana V bituminous coal (Table I). Base line data is shown in Figure 4. All three tests, Kinetic, SRT, and Equilibrium, show an increase in coal conversion with an increase in the concentration of tetralin. The Equilibrium Test shows the highest coal conversion of approximately 86 wt% of the MAF coal (based on the solubility in the tetrahydrofuran) at the 50% tetralin concentration. The Kinetic Test shows lower coal conversion. The hydrogen transferred to the coal from the tetralin in the Equilibrium Test at the 50 wt% tetralin feed concentration is approximately 0.5 wt% of the MAF coal. In the Kinetic Test 50 wt% tetralin feed concentration results in a much smaller transfer at the short reaction time of 10 minutes. 

If your compound does not happen to dissolve in CC14, you still have a shot because deuterium atoms do not give PMR signals. This is logical, since they re not protons. The problem is that deuterated solvents are expensive, so do NOT ask for, say, D20 or CDC13, the deuterated analogs of water and chloroform, unless you re absolutely sure your compound will dissolve in them. Always use the protonic solvents — H20 or CHC13 here — for the solubility test. There are other deuterated solvents, and they may or may not be available for use. Check with your instructor. 

Allelopathic test materials and controls. Some 2.5 mL of aqueous or organic extracts were required for thorough saturation. Water-soluble or partially water-soluble extracts were appUed directly to the filter paper. Distilled water controls were used. With organic solvent-soluble extracts, the solution was applied to the filter paper and allowed to dry, then distilled water was added to support germination. Controls having pure solvent applied were similarly allowed to dry before the distilled water was added, ( antification of the amount of allelopathic material applied to each sample... 

Solvents 1 and 2 are known to be good solvents for poly(methyl methacrylate) solvent 3 readily dissolves polystyrene.The solubility tests show that the radically polymerized sample is insoluble in all three solvents.The solubility isthusdifferentfrom that of both poly(methyl methacrylate) and polystyrene.The anionically polymerized product dissolves on warming in the acetone/methanol mixture and also in acetonitrile it is insoluble in cyclohexane/toluene.The solubility is thus similar to that of poly(methyl methacrylate). For the cationically initiated polymerization the product is only slightly soluble in acetone/methanol, insoluble in acetonitrile, but very readily soluble in cyclohexane/toluene.The solubility thus resembles that of polystyrene. 

A) Generate retention volume chromatograms in tetrahydrofuran and TFE from test polymer samples, which are not necessarily narrow in molecular weight distribution and need not be characterized but are soluble in TFE and cover the retention volume range of interest in both solvents. The test polymers used were PMMA samples. 

With some varnishes, especially those with a basis of alcohol, acetone or other solvent soluble in water, it is preferable. In order to avoid useless dilution, to distil directly rather than in steam. 50 grams of the varnish are weighed in a distillation flask provided with a thermometer, and heated on an oil-bath until the solvent is completely eliminated, the temperature being observed meanwhile. The specific gravity of the distillate at 150 is measured and the tests indicated under A applied. 

Different polar organic solvents were tested as background electrolytes, and Af-methy 1 formamide was found to have the best properties with respect to both electrophoretic behaviour and high solubility of the interested compounds. The method was found to be precise (1.8% RSD for normalized peak areas), with good linearity and a low detection limit. 

With new sets of labeled test tubes containing the solids listed above, repeat the solubility tests using the solvents ethanol (ethyl alcohol), C2H5OH, acetone, (CH3)2CO, and petroleum ether in place of the water. Record your observations. 

D 1581 Test Method for Bonding Permanency of Water- or Solvent-Soluble Liquid... 

Negative substituents enhance the acidic properties of phenols, an effect opposite to that produced with aromatic amines. o and p-Chloro-phenols are considerably stronger acids than phenol itself, and o- and p-nitrophenols are still stronger. Trinitrophenol, picric acid, is a strong acid whose salts are neutral and not decomposed by carbonic acid or by ammonium salts. These salts of picric acid can be salted out of neutral solutions by sodium or potassium chloride. With negatively substituted phenols, it may be possible to separate the phenolate from solutions which are neutral or weakly alkaline to litmus. In doubtful cases, just as with the amines, the precipitated material must be studied to determine whether it is the free phenol or one of its salts. The color of the precipitate gives an indication in the case of the nitrophenols, since the free phenols have only a weak yellow color, whereas the alkali salts are deep yellow. Solubility tests with indififerent solvents may be used in the case of uncolored compounds. Only the free phenol can be separated from acidic solutions. 

Based on the success of the batch autoclave experiments, continuous liquefaction and coprocessing tests using [(NH4)2MoS4l were made. High coal conversions to solvent-soluble and distillate products were observed at 450 C. Typical continuous unit results in both liquefaction and coprocessing modes at 450°C are presented in Table HI. 

Solubility test, for enzyme purity, 285 Solvation, effect on ring structure and conformation, 33 Solvents... 

From your solvent selection tests (Box 3.1) you will have discovered the individu l solvents in which your compound is soluble (good solvents) and in which it is insoluble (poor solvents), when the solvents are cold. Proceed as follows . -... 

Examptes Suppose that you have prepared a crude sample (e.g. 4.0g) of A/-phenylbenzamide (benzani-lide). Your solvent selection tests have shown that it is insoluble in water and fairly soluble in cold ethanol. The melting point of pure A/-phenylbenzamide is 158 C (Lide, 2000). Proceed as follows ... 

Make solubility tests on the test compounds shown to the left in each of the solvents listed. Note the degree of solubility in the solvents, cold and hot, and suggest suitable solvents, solvent-pairs, or other expedients for crystallization of each substance. Record the crystal form, at least to the extent of distinguishing between needles (pointed crystals), plates (flat and thin), and prisms. How do your observations conform to the generalization that like dissolves like ... 

You are to purify 2.0 g of an unknown provided by the instructor. Conduct tests for solubility and ability to crystallize in several organic solvents, solvent pairs, and water. Conserve your unknown by using very small quantities for solubility tests. If only a drop or two of solvent is used the solvent can be evaporated by heating the test tube on the steam bath or sand bath and the residue can be used for another test. Submit as much pure product as possible with evidence of its purity (i.e., the melting point). From the posted list identify the unknown. 

Plan a procedure for separating 2.0 g of the mixture into its components and have the plan checked by the instructor before proceeding. A flow sheet is a convenient way to present the plan. Using solubility tests, select the correct solvent or mixture of solvents to crystallize 4-chloroaniline. Determine the weights and melting points of the isolated and purified products and calculate the percent recovery of each. T urn in the products in neatly labeled vicils. 

The choice of the solvent for a particular crystallization depends on several factors. The first, of course, is that it should dissolve, when hot, an appreciable amount of the substance to be purified without reacting chemically with it. In addition, the solvent should be relatively safe to handle (not poisonous or infiammable) and easy to remove from the filtered crystals. Some of the solvents most commonly used for crystallization are given in Table 1. The solvent is selected on the basis of solubility tests. One method of performing these tests is to place 0.1 g of the substance in a small test tube and then to add 1 ml of the warm solvent. If all the solid does not dissolve even on heating, then another ml of the solvent is added, and heat again applied. If a total of 3 ml is added and the substance does not dissolve when heated, then the substance is regarded as difficultly soluble in that solvent. Such a solvent is not suitable for crystallization, for it would require more than 100 ml of hot solvent to dissolve 2-3 g of the substance. Care should be exercised to distinguish small solubility from the presence of insoluble impurities. 

The IR spectrum of the polymer film prepared under Condition B is shown in Fig. 23. A structure close to polystyrene is revealed as evidenced by peaks at 540, 700, 760, 840, 1070, 1450, 1490 and 1600 cm . Solubility tests with various solvents proved that the polymer was highly cross-linked. The spectrum of the polymer powder is quite different from that of the film. Peaks assignable to acrylic ester and/or epoxy groups (3400, 1720, 1600, 1500, 1200 and 820 cm ) prevail in that spectrum together with that of polystyrene as shown in Fig. 24. Oxidation of the polymer may be the result of reaction with oxygen in the air after the polymer was taken out from the reactor, as pointed out by several authors (8). It suggests that the powder contains many more active sites, e.g. radicals, than the film. The spectrum corresponding to Condition A is shown in Fig. 25, and is seen to have features similar to both of the previous spectra. Thus, it is seen that the structure of the plasma-polymer depends on the polymerization conditions. 

B) Natural fiber solubility tests Here the same general procedure and test tube set-up will be used except that we will be testing the solubility of three natural fibers - cotton, wool and silk in two solvents ... 

Figure 12 Filter plate method for solubility testing. (1) Add compound dissolved in organic solvent to aqueous buffer. (2) Shake for 90 minutes to allow insoluble compound to precipitate. (3) Apply vacuum to filter solution into collection plate. Precipitates remain on membrane. Analyze filtrate in collection plate to quantify the amount of the compound still in the solution. Source Courtesy of Millipore Corporation, Billerica, Massachusetts, U.S.A.

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