Crystalline turbidity

The calcium cation produces many relatively insoluble salts. The most insoluble is calcium oxalate. Oxalic acid is used to demonstrate the presence of calcium in a liquid as it causes turbidity and precipitation. Calcium tartrate is also relatively insoluble, especially in the presence of ethanol (Section 1.6.5). In the same way, calcium gluconate and mucate, present in wine made from botrytized grapes, are reputed to be responsible for crystalline turbidity (Section 1.2.2). Calcium concentrations in white wines are between 80 and 140 mg/1, while they are slightly lower in red wines. The calcium content may increase following deacidification with calcium carbonate. As calcium is divalent, it is more energetically involved than potassium in colloid flocculation and precipitation, e.g. ferric phosphate, tannin-gelatin complexes, etc. 

Introduce 197 g. of anhydrous brucine or 215 g. of the air-dried dihydrate (4) into a warm solution of 139 g. of dZ-acc.-octyl hj drogen phthalate in 300 ml. of acetone and warm the mixture vmder reflux on a water bath until the solution is clear. Upon cooling, the brucine salt (dA, IB) separates as a crystalline solid. Filter this off on a sintered glass funnel, press it well to remove mother liquor, and wash it in the funnel with 125 ml. of acetone. Set the combined filtrate and washings (W) aside. Cover the crystals with acetone and add, slowly and with stirriug, a slight excess (to Congo red) of dilute hydrochloric acid (1 1 by volume about 60 ml.) if the solution becomes turbid before the introduction of... 

As-polymerized PVDC is not in its most stable state annealing and recrystaUization can raise the temperature at which it dissolves (78). Low crystallinity polymers dissolve at a lower temperature, forming metastable solutions. However, on standing at the dissolving temperature, they gel or become turbid, indicating recrystaUization into a more stable form. 

One gram of 6,7-dihydro-5H-dibenz[c,e] azepine hydrochloride was dissolved in water, made alkaline with concentrated ammonia, and the resultant base extracted twice with benzene. The benzene layers were combined, dried with anhydrous potassium carbonate, and mixed with 0.261 g of allyl bromide at 25°-30°C. The reaction solution became turbid within a few minutes and showed a considerable crystalline deposit after standing 3 A days. The mixture was warmed VA hours on the steam bath in a loosely-stoppered flask, then cooled and filtered. The filtrate was washed twice with water and the benzene layer evaporated at diminished pressure. The liquid residue was dissolved in alcohol, shaken with charcoal and filtered. Addition to the filtrate of 0.3 gram of 85% phosphoric acid in alcohol gave a clear solution which, when seeded and rubbed, yielded 6-allyl-6,7-dihydro-5H-dlbenz[c,e] azepine phosphate, MP about 211°-215°C with decomposition. 

On evaporation of the ethyl ether from the ethyl ether solution, the benzhydryl ether was recovered as a pale yellow oil. The benzhydryl ether was dissolved in 60 ml of isopropanol and the isopropanol solution acidified to a pH of 3 with dry hydrogen chloride-methanol solution. The acidic propanol solution was then diluted with ethyl ether until a faint turbidity was observed. In a short time, the crystalline hydrochloride salt of the benzhydryl ether separated from the propanol solution. The crystallized salt was recrystallized once from 75 ml of isopropanol with the aid of ethyl ether in order to further purify the material. A yield of the pure hydrochloride salt of 1-methylpiperidyl-4-benzhydryl ether of 24.5 grams was obtained. This was 39% of the theoretical yield. The pure material had a melting point of 206°C. 

When polyisobutylene (PIB) was added to an aqueous solution of either y-CD or / -CD and then sonicated at room temperature, the mixture became turbid and precipitated a crystalline complex. Figure 20 shows how the complexation... 

B. 2-Methylmercapto-N-methyl-A l-pyrrolinium iodide. N-MethyI-2-pyrrolidinethione (310 g., 2.69 moles) is dissolved with stirring in 1.1 1. of anhydrous ether in a 2-1. three-necked flask equipped with a mechanical stirrer, a reflux condenser fitted with a drying tube, and a dropping funnel. To this solution is added ca. 5 g. of the product as seed crystals (Note 4) to prevent initial deposition of the iodide as an oil that suddenly crystallizes with considerable evolution of heat. Methyl iodide (520 g., 3.66 moles) is then added rather rapidly. The solution becomes turbid after a short time, and separation of the salt begins with heat evolution. After 12 hours the hygroscopic, crystalline paste is filtered and dried in a desiccator yield 663 g. (96%). 

Apart from DAB-dendr-(CN)4, which is a white crystalline solid, all generations are colorless to slightly yellow oils. The amine-terminated dendrimers are transparent, whereas the nitrile-terminated products are somewhat turbid. The solubility of the dendrimers is determined primarily by the nature of the end-group DAB-dendr-(NH2)n is soluble in H20, methanol and toluene, whereas DAB-dendr-(CN)n is soluble in a variety of common organic solvents. 

The initial stages of the DBX-1 synthesis using Cun-purified NaNT in place of raw NaNT produced similar observations as described above. Upon addition of the initial dose of sodium ascorbate, a gel-like material was formed with no evidence of crystalline DBX-1. After an apparent induction period of several minutes, a very different phenomenon was noticed. These events included a visual change in reaction mixture turbidity (it became clear) and an almost instantaneous drop in the counts of fine particles (see Figure 1). As the fines dropped the PVM almost instantaneously identified crystalline DBX-1 (see Figure 2). The event only lasted seconds and produced the beautiful rust colored crystals indicative of DBX-1 product. The second dose of reducing agent was started (denoted by the second start on the x axis) after formation of the DBX-1 crystals was identified. 

Benzoylazide.3—14 g. (0-1 mole) of the dry hydrazide are made into a clear solution with 200 c.c. of approximately N-hydrochloric acid in a filter jar (capacity 0-5 1.). The solution is cooled in ice and stirred, while 8 g. of sodium nitrite in 50 c.c. of water are added. An immediate reaction takes place and the azide separates in crystalline form. When a filtered sample of the solution is no longer made turbid by the addition of a drop of nitrite solution, the precipitate is filtered dry at the pump, washed well with water, and dried, first on porous plate and then in a vacuum desiccator over concentrated sulphuric acid and potassium hydroxide. Yield 14 g. 

Suto et al. (102) studied the effects of salts on the turbidity and viscometric behavior of HPC mesophases in water and the rheology of liquid crystalline solutions of HPC in m-cresol (103). Suto (104) found that crosslinking HPC mesophases in water destroyed their order. 

Our understanding of lyotropic liquid crystals follows in a similar manner. The action of solvent on a crystalline substance disrupts the lattice structure and most compounds pass into solution. However, some compounds yield liquid crystal solutions that possess long-range ordering intermediate between solutions and crystal. The lyotropic liquid crystal can pass into the solution state by the addition of more solvent and/or heating to a higher temperature. Thermotropic and lyotropic liquid crystals, both turbid in appearance, become clear when they pass itno the liquid and solution states, respectively. 

Due to light scattering, crystalline polymers mostly yield turbid films.Their blends with other polymers are always demixed because polymers are not able to form mixed crystals. Consequently, crystallizable polymers only yield homogeneous blends above their melting point. As soon as crystallization sets in, the components will separate. 

Brown crystalline solid deliquesces decomposes on heating moderately soluble in water, forming a turbid solution hydrolyzes in excess water forming a brown basic salt soluble in dilute nitric acid. 

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