Silver ethanol concentration

All silver mirrors were prepared by electroless deposition using the commercial solutions and general procedures supplied by London Laboratories, Ltd. (Woodbridge, Conn.). For Korad film, however, the aqueous solutions were modified with ethanol to improve adhesion of the silver to the polymer. An ethanol concentration of 4.8 vol % was used in the sensitizing, silvering, and reducing solutions. The silver in our mirrors is approximately 600 to 700 A thick. 

Preparation of o-arabinose diphenylhydraxone from pentaacetyl-xi-glucononitrile, To a cold solution of 100 g. of pentaacetyl-n-glucononitrile in 280 ml. of 96% ethanol, 34 g. of silver oxide (from about 50 g. of silver nitrate) dissolved in 500 ml. of 30% ammonia was added. After forty-eight hours the separated crystalline silver cyanide was removed by filtration and the filtrate concentrated in vacuo to about one-third of the original volume and filtered. Water was added to 500 ml., and the dissolved... 

The procedure to fabricate colloidal silver, (Ag°) , spherical nanoparticles is similar to that already described (see Section 9.3.3) The Cu( AOT)2 is replaced by the silver derivative. The relative concentration of Na(AOT), Ag(AOT)2, and the reducing agent remain the same. Control of the particle size is obtained from 2 nm to 6 nm (67). To stabilize the particles and to prevent their growth, 1 p.l/mL of pure dodecanethiol is added to the reverse micellar system containing the particles. This induces a selective reaction at the interface, with covalent attachment, between thio derivatives and silver atoms (68). The micellar solution is evaporated at 60°C, and a solid mixture of dodecanethiol-coated nanoparticles and surfactant is obtained. To remove the AOT and excess dodecanethiol surfactant, a large amount of ethanol is added and the particles are dried and dispersed in heptane. A slight size selection occurs, and the size distribution drops from 43% to 37%. The size distribution is reduced through the size selected precipitation (SSP) technique (38). 

To a solution of silver tetrafluoroborate (0.77 g, 4.0 mmol) in 20 mL of ethanol, 2,4-dimethylpenta-1,3-diene (0.62 g, 6.5 mmol), and 2 mL of benzene are added. This solution is added dropwise to a vigorously stirred solution of product A (0.61 g, 2.0 mmol), in 15 mL of dichloromethane. Silver chloride is separated by centrifugation and decanting the supernatant liquids and then it is washed with 5 mL of dichloromethane. The combined dichloromethane solutions are concentrated to 5 mL, and the orange product is precipitated by addition of an equal volume of diethyl ether. Yield 75%. 

Tests for carboxylic acids were made by paper chromatography using 95% ethanol (100 ml.) and concentrated ammonium hydroxide (1 ml.) as solvent and aqueous bromothymol blue as indicator (1). Tests for pyridines were made on their hydrochlorides using butanol-.acetic acid water (4 1 5) as solvent and ammoniacal iron chloride or cysteine-sulfuric acid as indicators. Phenol tests were made using the same solvent and ammoniacal silver nitrate as indicator. Preliminary separations by gas chromatography were attempted using a 15-foot silicone gum column and a hydrogen flame attachment. 

To a solution of silver triiluoromethanesulfonate (7.71 g, 30 mmol) in dry dichloromethane (100 mL) at —40°C in the dark is added dropwise a solution of 9-fluorenylmethoxycarbonyl serine benzyl ester 11 (8.45 g, 20 mmol), 2,3,4-tri-O-benzoyl-a-D-xylopyranosyl bromide 12 (11.14 g, 21.2 mmol) and tetramethyl urea (3.65 g, 31.4 mmol) in dichloromethane (100 mL). After 18 h of stirring at room temperature, the precipitate is filtered off and washed with dichloromethane (200 mL). The organic solution is washed with water (200 mL), 1% KHCOj solution (twice 200 mL) and water, dried with Na SO, and concentrated in vacuo. The crude product is recrystallized from ethyl acetate-n-hexane. (If the reaction was not complete, chromatography on silica gel 60 in toluene/ethanol 9 1 is recommended). Yield 15 g (87%) mp 136°C, [ot]D -27.8° (c 1.3, CHC13), Rf 0.64 (toluene/ethanol 26 1). 

Which compound in each of the following pairs would you expect to react more readily with (A) potassium iodide in 2-propanone, (B) concentrated sodium hydroxide in ethanol, and (C) silver nitrate in aqueous ethanol Write equations for all the reactions involved and give your reasoning with respect to the predicted orders of reactivity. 

The following procedure is more suitable for routine application than other methods as many as 200 specimens can be processed at a time with this procedure. Sections (2 pm thick) of formalin-fixed and paraffin-embedded tissues are mounted on silane-coated slides. They are deparaffmized with xylene and rehydrated in a series of descending concentrations of ethanol. The sections are immersed in 0.01 M sodium citrate buffer (pH 6.0) in plastic Coplin jars and heated in an autoclave at 120°C for 20min. After the sections have cooled down to room temperature for 20 min, they are incubated in the freshly prepared following silver staining solution for 25 min at room temperature. 

The sections are thoroughly rinsed in deionized water to remove unwanted silver precipitates, dehydrated in a series of ascending concentrations of ethanol, cleared in xylene, and... 

Dry ethanol and concentrated sulfuric acid Silver nitrate Evolves ethyl acetate (fruity odor) upon heating dry isoamyl alcohol may be substituted for ethanol Formation of white precipitate of silver acetate that is soluble in dilute ammonia solution... 

A 33.0 g (0.135 mole) of 2-methylthio-2-imidazoline hydroiodide is dissolved in 300 ml of water and treated with 8 ml (0.16 mole) of hydrazine hydrate. The mixture is stirred at room temperature for 20 hours and then taken to dryness under reduced pressure. The residue is dissolved in 250 ml of water and again taken to dryness under reduced pressure. The residue is redissolved in 250 ml of water and added to a mixture of 250 ml of water, 25 ml of concentrated hydrochloric acid and 25 g of silver oxide. The resulting mixture is stirred on a steam bath for 4 hours and then filtered. The filtrate is reduced to dryness under reduced pressure. The residue is dissolved in 300 ml of ethanol and 20 ml of water at the boil, clarified and cooled at -10°C. 

The mixture is suction filtered, the precipitate being collected on a tared, Pyrex-glass filtering crucible of medium porosity. The product is next washed several times with small portions of water until the washings are free of chloride ion, as tested with silver nitrate solution. Finally, it is washed with a little ethanol followed by a little ether. The crucible containing the product is placed in a vacuum desiccator over concentrated sulfuric acid and dried for 1 day with occasional addition of nitrogen to the desiccator, followed by reevacuation. The yield of chromium(II) acetate is 6.1 g. (95% of theory). 

Organochloride. For the estimation of chlorine containing insecticides, the developed plate is sprayed with a 1.0% ethanolic silver nitrate solution containing five milliliters of concentrated ammonia solution. After drying the sprayed plate in air, it is irradiated with U.V. light (366 nm) for ten minutes. After exactly ten minutes, the area of the developed spots is measured and compared with that of the control insecticide run on the same TLC plate. 

All cell potentials reached equilibrium in 1 or 2 hr, except when the solvent was anhydrous terf-butanol, in which the electrodes reached equilibrium only in dilute soltuions of HBr and even then only in a sluggish manner. This sluggish behavior has been reported (27) for the silver-silver bromide electrode in anhydrous ethanol when the acid was concentrated. In the dilute hydrobromic acid solutions used here, this phenomena was not observed in anhydrous ethanol. It is estimated that the standard electrode potential of the silver-silver bromide electrode in anhydrous terf-butanol is accurate to only d=l mV. However, these data are reported to the same degree of precision found in the other tert-buta-nol-water solvents in order to facilitate comparisons of the emf s in the various dilutions of tert-butanol used. 

Tetrakis(L)copper(I) or Silver (I) Perchlorate prom Isomers A AND B. To a suspension of 0.7 g. (4 mmoles) of isomer A or B in 25 ml. of acetone was added 1 mmole of copper(II) perchlorate hexahydrate or anhydrous silver(I) perchlorate, and the suspension was stirred for 18 hrs. The colorless copper complex was filtered off and dried under vacuum at room temperature. Some reduction to silver metal occurred in the reaction of silver perchlorate. The precipitate was therefore extracted with ethanol, and the extract was filtered and concentrated to obtain the complex. Approximately 30% yields of both compounds were obtained. 

Figure 2. Dependence of the intensity of the 384 cm band in SERS spectrum of CuTMpyP4 on the Ag deposition time for (A, B) meso-PS and (C, D) macro-PS the AgNOj concentration was (1) 1-10 M and (2) l lO M. (A, C) correspond to the silver deposition from aqueous solution, (B, D) correspond to the silver deposition from the (1 1) water ethanol mixture.

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