Hydrochloric acid, solution preparation

To the aqueous suspension of the palladized charcoal catalyst thus obtained are added 20.8 kg of 3-cyano-pyridine (96% purity) and then are added 70 liters of a hydrochloric acid solution prepared by diluting 30 liters of 36% HCI with 40 liters of water. This represents approximately 1.75 mols of HCI for each mol of 3-cyano-pyridine. The suspension is maintained at 10° to 15°C and stirred continuously while introducing a current of hydrogen at a pressure of 3 to 5 psi. When absorption of hydrogen ceases and the 3-cyano-pyridine is completely reduced, the reaction mixture is filtered to remove the catalyst. 

The only known trivalent tungsten complex is of the type M(I)2(W2Cl2). It is prepared by the reduction of strong hydrochloric acid solutions of K2WO4 with tin. If the reduction is not sufficient, a compound containing tetravalent tungsten, K2(WCl (OH)) [84238-10-0] is formed (57). 

Dichloroanthraquinone [82-46-2] (46) is an important iatermediate for vat dyes and disperse blue dyes. Examples are Cl Vat Violet 13 [4424-87-7] (170), Cl Vat Orange 15 [2379-78-4] (154), and Cl Disperse Blue 56 [31810-89-6] (11). 1,5-DichloroantliraquiQone is prepared by the reaction of anthraquiQone-l,5-disulfonic acid with NaClO iu hot hydrochloric acid solution. Alternative methods from 1,5-dinitroanthraquiaone (49) by reaction of chlorine at high temperature ia the presence of phthaUc anhydride have been proposed (66). 

BrCl can be prepared by the reaction in the gas phase or in aqueous hydrochloric acid solution. In the laboratory, BrCl is prepared by oxidizing bromide salt in a solution containing hydrochloric acid. 

Tile tartaric acid is finely powdered and mi.Ked with half the above quantity (80 c.c.) of absolute alcohol. The mixture is heated on the water-bath with upright condenser until dissolved. The flask is immersed in cold water, and the well-cooled solution saturated with dry hydrochloric acid gas (prepared in the usual way by dropping cone, sulphuric acid into cone, hydiochloric acid, see Fig. 65, p. 93). After standing for an... 

The free base was then dissoived in absolute methanol, and the resulting solution was then adjusted to an acid pH value with an ethereal hydrochloric acid solution. The acidified solution was purified with charcoal and then dry ether was added thereto until crystallization took place. The hydrochloride, prepared in this customary manner, had a melting point of 305°C according to U.S. Patent 3,202,660. 

It is not necessary that the intermediate be separated from the reaction medium in the preparation of the end product. Instead, the reaction mixture, after cooling, is treated with 200 ml of water acidified with 42 ml 10% hydrochloric acid solution, and filtered. To the clear, light yellow filtrate is added dropwise a solution of 9.B g (0.07 mol) 5-nltro-2-furaldehyde in 100 ml ethyl alcohol. An orange solution of the hydrochloride results. The free base is precipitated asyellow plates by making the solution basic with saturated sodium carbonate solution. 14 g of the compound is filtered off by suction, washed with alcohol, and dried. The yield, MP 204°C to 205°C (dec.), is 53% of theoretical based on 3-(N-morpholinyl)-1,2-epoxy-propane. Recrystallization from 95% alcohol (75% recovery) raises the melting point to 206°C (dec.). 

The standard redox potential is 1.14 volts the formal potential is 1.06 volts in 1M hydrochloric acid solution. The colour change, however, occurs at about 1.12 volts, because the colour of the reduced form (deep red) is so much more intense than that of the oxidised form (pale blue). The indicator is of great value in the titration of iron(II) salts and other substances with cerium(IV) sulphate solutions. It is prepared by dissolving 1,10-phenanthroline hydrate (relative molecular mass= 198.1) in the calculated quantity of 0.02M acid-free iron(II) sulphate, and is therefore l,10-phenanthroline-iron(II) complex sulphate (known as ferroin). One drop is usually sufficient in a titration this is equivalent to less than 0.01 mL of 0.05 M oxidising agent, and hence the indicator blank is negligible at this or higher concentrations. 

Prepare a blank solution by carrying through all the sequences of the separation procedures using a hydrochloric acid solution to which no alloy has been added, and then measure the absorption given by this blank solution, by a series of standard solutions containing from 1 to 10 /rg Pb mL 1 prepared by suitable dilution of the lead caprate stock solution (see Note), and finally of the extract prepared from the sample of alloy. Plot the calibration curve and determine the lead content of the alloy. 

In very dilute HCl solutions, specifically those with a pH above 5-48, the 4 1 5 phase was found to be insoluble. By contrast, addition of concentrated HCl to the 4 1 5 phase was shown to lead to formation of the 1 1 2 phase (Sorrell, 1977). Below 35wt% HCl, the 4 1 5 phase was found to dissolve congruently. Since the 1 1 2 phase was also found to dissolve congruently in hydrochloric acid solutions with concentrations above 23 wt %, it follows that there is a range of concentrations over which both phases are soluble in aqueous HCl. This behaviour explains why the zinc oxychlorides have proved to be unsatisfactory in attempts to use them as dental cements. The preparation of such cements from concentrated aqueous solutions of ZnClj results in the formation either of the 1 1 2 phase alone or of mixtures of the 4 1 5 and 1 1 2 phases, neither of which is stable in the presence of water. Preparing dental cements from less concentrated solutions also results in the formation of mixed phases, unless the bulk composition has excessive amounts of ZnO present. In these latter cases the cement stability is acceptable but it lacks both a workable consistency and a reasonable working time. 

Crystals of [Tc(tu)6]Cl3 or [TcCl(tu)5]Cl2 are often employed for the synthesis of technetium(III) complexes. However, since the direct reduction of pertechnetate with excess thiourea in a hydrochloric acid solution yields [Tc(tu)6]3+ in high yield [37], direct use of the aqueous solution of the thiourea complex would be preferable for the synthesis of the technetium(III) complex without isolation of the crystals of the thiourea complex. In fact, technetium could be extracted from the aqueous solution of the Tc-thiourea complex with acetylacetone-benzene solution in two steps [38]. More than 95% extraction of technetium was attained using the following procedure [39] First a pertechnetate solution was added to a 0.5 M thiourea solution in 1 M hydrochloric acid. The solution turned red-orange as the Tc(III)-thiourea complex formed. Next, a benzene solution containing a suitable concentration of acetylacetone was added. After the mixture was shaken for a sufficient time (preliminary extraction), the pH of the aqueous phase was adjusted to 4.3 and the aqueous solution was shaken with a freshly prepared acetylacetonebenzene solution (main extraction). The extraction behavior of the technetium complex is shown in Fig. 6. The chemical species extracted into the organic phase seemed to differ from tris(acetylacetonato)technetium(III). Kinetic analysis of the two step extraction mechanism showed that the formation of 4,6-dimethylpyrimidine-... 

The light-absorbing impurities of oxytetracycline hydrochloride and oxytetracycline dihydrate [2,4,6] are detected using a UV-spectrophotometric method. In all the compendia, the absorbance of a solution of 2.0 mg/mL in a mixture of 1 volume of hydrochloric acid solution (0.1 mol/L) and 99 volumes of methanol at 430 nm not greater than 0.50 is required the absorbance of a solution of 10 mg/mL in the same solvent at 490 nm is not greater than 0.20. The measurements are carried out within 1 h of the preparation of the solutions. 

In order to achieve the firm fixation of the artificial cornea to host tissues, composites of collagen-immobilized poly(vinyl alcohol) hydrogel with hydroxyapatite were synthesized by a hydroxyapatite particles kneading method. The preparation method, characterization, and the results of corneal cell adhesion and proliferation on the composite material were studied. PVA-COL-HAp composites were successfully synthesized. A micro-porous structure of the PVA-COL-HAp could be introduced by hydrochloric acid treatment and the porosity could be controlled by the pH of the hydrochloric acid solution, the treatment time, and the crystallinity of the HAp particles. Chick embryonic keratocyto-like cells were well attached and proliferated on the PVA-COL-HAp composites. This material showed potential for keratoprosthesis application. Further study such as a long-term animal study is now required [241]. 

Calculate the pH of an acidic solution prepared by adding enough water to 5 grams of hydrochloric acid to make a solution that has a volume of 1 liter. 

Approximately 8N hydrochloric acid solution was prepared by addition of 100 ml. of water to 200 ml. of 37.5% hydrochloric acid. 

B. 2- (1-Phenylcyclopentyl)-4,4,6-trimethyltetrahydro-1, Z-oxa-zim. To a 600-ml. beaker containing a magnetic stirring bar are added 200 ml. of tetrahydrofuran, 200 ml. of 95% ethyl alcohol, and 25.0 g. (0.092 mole) of the oxazine obtained in Part A. The mixture is stirred and cooled to —35 to —40° with an acetone bath to which dry ice is added as needed. A 9N hydrochloric acid solution is added dropwise to the stirred solution until an approximate pH of 7 is obtained as determined by pll paper. A solution of sodium borohydride is prepared by dissolving 5.0 g. (0.13 mole) in a minimum amount of water... 

Little attention was paid to these reactions until 1921 when Hoffman 174-176) prepared tetrakis(hydroxymethyl)phosphonium chloride by passing phosphine into a warm, aqueous hydrochloric acid solution of formaldehyde. The product was obtained in the form of colourless crystals by evaporation of the reaction solution. 

By the action of nitrous acid in hydrochloric acid solution on bromo-phenylcystine, prepared by Baumann s method, chlorobromophenyl-thiopropionic acid was obtained, which, on reduction, gave bromophenyl-thiolactic acid. This was identical with the substance prepared from j8-iodopropionic acid and sodium bromophenylmercaptan —... 

The compound is prepared by dissolving zirconium tetrachloride, ZrCh, or sodium zirconate, Na4Zr04, in hydrochloric acid solution followed by evaporation to obtain crystals of octahydrate. 

Aquo - pentammino - cobaltic Chloride, [ o(NH3)5.H20]C13, is also best prepared from the oxalate. The oxalate is moistened with water and brought into solution by the addition of normal hydrochloric acid. On the addition of concentrated acid the chloride is precipitated as an indistinctly crystalline brick-red powder. The salt is soluble in cold water, and is readily transformed into the aeido-salt on heating to 100° C. It also passes into the aeido-salt on heating in hydrochloric acid solution thus ... 

The traditional method of oxidizing hydrazine derivatives makes use of halogens or hypohalites as oxidizing agents. The techniques range from the preparation of l,l -azobis(l-cyclohexanenitrile) by the addition of bromine to an alcoholic hydrochloric acid solution of the corresponding hydrazine [89], through the use of bromine water [90, 91] to oxidations with sodium hypo-bromite [64] or sodium hypochlorite [92]. 

In a 1 liter, three-necked flask equipped with a mechanical stirrer, addition funnel, and a gas outlet, a solution of 138.4 gm (0.62 mole) of 2,5-diphenyl-pyrrolidine in 210 ml of ethanol and 100 ml of concentrated hydrochloric acid is prepared. While vigorous stirring is continued, the solution is cooled in an ice bath and, over a 2 hr period, a solution of 61.5 gm (0.891 mole) of sodium nitrite in 100 ml of water is added dropwise. Stirring is continued overnight while the reaction mixture comes to room temperature. To isolate the product, the reaction mixture is poured into 1 liter of water and the resultant precipitate is collected on a filter. The crude product is thoroughly washed with water. Yield of crude product is 160 gm. 

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