Alkaline solution, inclusion

Degreasing by cathodic treatment in a hot alkaline solution is desirable when the copper contains inclusions of cuprous oxide. Pickling may be carried out in either cold 50% hydrochloric acid or 20% v/v nitric acid, or in hot (70°C) 6% v/v sulphuric acid containing 1.5% w/w sodium dichromate. 

As an alternative method of procedure, the following may be substituted for Steps 4 to 7 inclusive of the above process. After distilling the benzol, the tarry mass may be stirred directly with 2000 mL of hot 0.3 N NaOH with a mechanical stirrer. The suspension is chilled and the supernatant Liquid poured or siphoned off. Repetition of the extraction two or three times is advisable. The alkaline aqueous solution is then extracted five or six times with 400 mL portions of sulfuric ether, thus transferring the hormone to ether solution. After distillation of the ether the residue is steam distilled as long as a distillate other than water is obtained. The condensed water is removed by vacuum distillation and the small amount of dark tarry residue leached 5 times with 50 mL of hot 0.3 N NaOH. This solution is filtered and the filtrate extracted with sulfuric ether (100 mL, 6 times). The ether solution is distilled and the residue leached with cold 0.3 N NaOH using 20 mL five times. This alkaline solution is filtered and extracted with 50 mL of sulfuric ether five times. Upon distillation of the ether and solution of the residue in a small quantity of hot ethyl alcohol, the hormone separates in semi-crystalline balls which may be filtered off. A further quantity is obtained by adding 3 volumes of water to the alcoholic solution. It may be recrystallized from 25% aqueous ethyl alcohol or from 25% aqueous acetone or from any of the following chloroform, benzol, ethyl acetate, ethyl ether or petroleum ether. The final product consists of colorless crystals which, when crystallized from dilute alcohol, possess a distinct rhomboid outline. The crystals melt at 242-243°C (248-249°C corrected) with some decomposition. 

Corrosion of Magnesium in Neutral and Alkaline Solutions Magnesium is highly susceptible to galvanic corrosion. Small amounts of impurities in the alloy can have a tremendous influence on the corrosion susceptibility. In Fig. 30, the influence of various elements is demonstrated. Small additions of copper, iron, nickel, and cobalt have an extremely negative effect on the corrosion resistance. The tolerance Kmit for iron is 0.015%, for nickel 0.0005%, and for copper 0.1% [35]. Because of the low solid solubility of these elements, they precipitate as inclusions. These act as active cathodic sites for the... 

Cho, Y, Xu, C., Cattrall, R. W, and Kolev, S. D. 2011. A polymer inclusion membrane for extracting thiocyanate from weakly alkaline solutions. Journal of Membrane Science 367 85-90. 

Nickel exhibits good corrosion resistance in neutral and alkaline solutions and in the atmosphere. However, it corrodes in strongly oxidizing acids. Chloride-containing environments may cause pitting corrosion, especially in commercial grade nickel that contains sulfide inclusions. Pure nickel is quite soft and is used mostly as a coating. 

Direct solution of the zinc electrode in the alkaline solution on open circuit is minimized by dissolving zinc oxide in the electrolyte and amalgamating the zinc in the electrode. Mercury levels used in zinc electrodes are usually in the range of 5 to 15% w/w. Great attention is also paid to the impurity levels in the zinc since minor cathodic inclusions in the electrode can drive the hydrogen generation reaction despite the precautions indicated. ... 

Reduction via inclusion complexes has received considerable attention because it allows both the diastereo- and enantioselectivity of the reaction to be controlled. Cyclodextrins and water-soluble cyclophanes are the most frequently used hosts in aqueous medium. P-CD/ketone (1 1) complexes suspended in NaBH4 aqueous alkaline solution give the corresponding alcohols quantitatively but with modest ee [75]. An improvement is obtained by using crystalline a-, P- and y-CD inclusion complexes of achiral amine-boranes at 0°C in heterogeneous aqueous medium [76]. Under these conditions, 1-phenylethanone and 4-phenyl-2-butanone give the (5) and (R) alcohol with 91% and 89% ee, respectively. 

D and 8 0 data on fluid inclusions and minerals at main stage of epithermal Au-Ag mineralization clearly indicate that the dominant source of ore fluids is meteoric water. Meteoric water penetrates downwards and is heated by the country rocks and/or intrusive rocks. The heated water interacts with country rocks and/or intrusive rocks and extracts sulfur, Au, Ag and other soft cations (e.g., Hg, Tl) from these rocks. If hydrothermal solution boils, it becomes neutral or slightly alkaline, leading to the selective leaching of soft cations such as Au, Ag, Hg and Tl from country rocks. However, a contribution of sulfur gas and other components from magma cannot be ruled out. 

Cl Sulphur Black 1, which is produced from the relatively simple intermediate 2,4-dinitrophenol and aqueous sodium polysulphide. A similar product (Cl Sulphur Black 2) is obtained from a mixture of 2,4-dinitrophenol and either picric acid (6.148 X = N02) or picramic acid (6.148 X = NH2). A black dye possessing superior fastness to chlorine when on the fibre (Cl Sulphur Black 11) can be made from the naphthalene intermediate 6.149 by heating it in a solution of sodium polysulphide in butanol. An equivalent reaction using the carbazole intermediate 6.150 gives rise to the reddish blue Cl Vat Blue 43 (Hydron blue). This important compound, which also possesses superior fastness properties, is classified as a sulphurised vat dye because it is normally applied from an alkaline sodium dithionite bath. Interestingly, inclusion of copper(II) sulphate in the sulphurisation of intermediate 6.150 leads to the formation of the bluish black Cl Sulphur Black 4. 

The impure metal dissolves easily in mineral acids and in fluoroboric, sulfamic am trifluoromethylsulfonic acids to give Cr2+ solutions, but oxidation of Cr2+ by hydrogen ion (equation 6), °(Cr3+, Cr2+) = —0.41 V) even in an inert atmosphere is catalyzed by thi impurities and various ions.71 Indefinitely stable chromium(II) solutions can be obtained fron the pure (electrolytic) metal (99.5% or better), although the reaction with acid may need to b< initiated by heat and the inclusion of some metal previously attacked by acid. The use of ai excess of metal, which can be filtered off, ensures that little acid remains. In near neutra solution the hydrogen potential is lowered and the Cr2+ ion is stable. In alkaline condition brown Cr(OH)2, which slowly reduces water, precipitates.73,73... 

Although there are many techniques used to clean such objects, commercial products are often simple solutions of ammonia within a hydrogen-based solvent, with the additional inclusion of a very fine and mild abrasive called diatomaceous earth (DE). DE is nearly pure silica, in the form of SiO2, with a very porous characteristic. DE consists of the skeletons of small aquatic unicellular algal organisms called diatoms, which have survived evolutionary processes for approximately 100 million years. Placed in the taxonomic family Bacillariophyceae, the cell walls of these creatures are made of silica. Because silica is more dense than seawater or freshwater, the presence of silica tends to cause diatoms to sink into the water depths. As such, DE is collected from the bottom of ancient lake beds and is currently mined and used for many commercial and industrial purposes. Thus, within metal cleaners, DE acts as an abrasive, and the alkaline ammonia dissolves any greasy residue on the metalware. In addition, the ammonia reacts with the CuO or CuS to form the soluble ammonia complex of copper, which is Cu(NH3)42+. The greasy tarnish residue can then be washed away with clean water and a damp cloth. 

It is known that the same red coloration and a similar spectrum can be produced for 5-trinitrobenzene dissolved in an alkaline ethanol solution (cf. 62). In this case the effect has been ascribed to the inclusion of OH" ions into the benzene ring, with the formation of covalent bonds... 

With enzyme determinations, standards for calibration purposes and for checking of instrumental performance make use of separately prepared solutions of one of the reactants or the products of the enzyme-catalyzed reaction. For instance, a solution of phenol may be standardized and thereafter used itself as the standard in determinations of acid and alkaline phosphatase, in methods employing phenyl phosphate as substrate and depending on the measurement of the amount of phenol liberated. This standard phenol solution, however, cannot be taken through all the steps in the determination of phosphatase, and a separate control solution must be used to check the performance of the overall technique if this control were omitted, it would be possible, for instance, for a buffer to be incorrectly prepared and for erroneous levels of phosphatase activity to be found. There is no substitute, therefore, in the control of enzyme determinations for the inclusion of a sample (of serum, urine, etc.) previously investigated for its level of enzyme activity. For long-term monitoring of an enzyme method, the repeated analysis of aliquots of a standardized enzyme preparation is most useful, provided... 

There are several important variations of this general process. Mesoporous solids can be prepared under alkaline, acid or neutral pHs, with cationic, anionic or neutral surfactants of different types. Furthermore, the synthesis can be influenced by the concentration and type of anions in the solution, by organic additives that concentrate within the core of the micelles and by the inclusion of other framework-forming cations. Aluminium, boron and titanium are among the many cations that can be introduced into mesoporous silicas, depending on whether acidic or alkaline synthesis conditions are adopted. 

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