HC1 acid

One gallon of 32% HC1 acid weighs approximately 9.7 lb therefore, the required volume of 32% HC1 acid solution is calculated by the following equation ... 

Societe Le Nickel (SLN) employ similar chemistry at their operations to treat mattes obtained from the pyrometallurgical treatment of Ni-bearing oxidic laterite ores.104 It has demonstrated at laboratory scale that Ni-containing lateritic ores may be directly leached into HC1 acid solution without pyrometallurgical pre-concentration at atmospheric pressure and relatively low temperature (ca. 70 °C).105... 

RP-HPLC has been employed for the determination of flavonoids and other phenolic compounds in cranberry juice. The neutral and acidic analytes were preconcentrated octadecyl silica SPE cartridges conditioned with distilled water (neutral analytes) or with 0.01 M HC1 (acidic compounds). Hydrolysis of samples was carried out in aqueous methanol solution acidified with 6 M HC1 at 35°C for 16h. Chromatographic separation was performed in an ODS column (150 X 4.6mm i.d. particle size 5/.an). Solvents A and B were water-acetic acid (97 3, v/v) and methanol, respectively. The gradient started with 0 per cent B (flow rate, 0.9 ml/min), reached 10 per cent B in lQmin (flowrate, 1.0 ml/min) and increased to 70 per cent B in 40min (flowrate, 1.0 ml/min). Analytes were detected at 280 and 360 nm. Some typical chromatograms are presented in Fig. 2.71. The concentrations of flavonoids and phenolic acids are compiled in Table 2.69. It was stated that the SPE-HPLC procedure makes possible the simultaneous determination of phenolic compounds and flavonoids, therefore, it can be employed for the measurement of these classes of analytes in other fruit juices [188],... 

An enzyme that catalyses ATP-dependent 2 -phosphorylation and acetyl-CoA-dependent 6 -acetylation of the antibacterial aminoglycosides has been reported.260 Because of its complementary spectrum of two enzymic reactions, this bifunctional enzyme has a wide breadth of activity. Pentacoordinated thiophosphorane intermediates such as (292a) and (292b) are involved in the hydrolytic reactions of the monothioate analogues of 5 -O-methyluridine 2 - and 3 -dhnethylphosphates, (293) and (294), which have been studied over a wide range of HC1 acidities, //<, = —1.7 to pH9.261... 

The HC1 acidic aoln. is diluted to 50 ml with H2O. The V is extracted into 10 ml CHCla hy addition of 2.5 ml 6 cupferron aqueous soln. and 10 ml CHCla. The extract is measured hy 7-spectrometry. Yield = k0. ... 

The Step 4 product (62.2 mmol) was dissolved in 350 ml THF, then treated with the dropwise addition of 1.4 M methyllithium in diethyl ether (189 mmol) at ambient temperature, and then stirred 2 hours. The mixture was quenched by pouring into saturated NH4C1 solution, acidified with 12 M HC1 acid, and extracted with diethyl ether. The ethereal layer was dried with Na2S04, concentrated, and an amber oil obtained. The residue was purified by chromatography using EtOAc/hexanes, 1 9, and the product isolated in 52% yield as an yellow solid, mp = 147—149°C. 

The photoadditions arc carried out in CH3OH solution in the presence of 37% HC1 acid by irradiating with a 200-W Hanovia lamp with 02 purging at 0 JC. The intermediate /1-amino nitrates are reduced to //-amino alcohols. 

Since H20 molecules appear to remain chemisorbed onto the dried CyD ICs, it was decided that photolyzing an aqueous suspension of 63 CyD could do no further harm and might even present an advantage. In deference to the instructive MeOH results (Scheme 15), the 63 CyD ICs were suspended in an alkaline buffer (to neutralize the HC1 byproduct) during subsequent photolysis experiments. Hence, the HC1 acid-catalyzed hydrolysis of any CyD benzylidene acetals, e.g., 73b (Fig. II),172 that may have formed would be thwarted. Indeed, such detrimental effects were remedied by conducting the photolyses in aqueous alkaline buffer (vide infra). 

HC1]—Acids react with certain metals to generate hydrogen gas. 

This equation shows us that the product of the concentrations of these ions must always be the same, 1.0 x 1014. This gives us the ability to calculate the concentration of one type of ion, when we know the concentration of the other type of ion. For example, if we know that the hydronium ion concentration of the HC1 acid solution that we created was 1.0 x 102 M, we could solve for the concentration of OH- ions, as shown here ... 

European Standard (1999) Characterisation of waste - Microwave assisted digestion with hydrofluoric (HF), nitric (HN03) and hydrochloric (HC1) acid mixture for subsequent determination of elements in waste, prEN 13356, Brussels. 

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