Hydrochloric Acid Chloride Research Articles

Environmentally friendly etching of stainless steel wire for plunger-in-needle liquid-phase microextraction of polycyclic aromatic hydrocarbons

An environmentally friendly method of etching a stainless steel plunger wire, to replace the conventional hydrofluoric acid approach, was developed for plunger-in-needle liquid phase-microextraction (PIN-LPME). The one-step etching procedure was performed by immersing the plunger wire in a ferric chloride-hydrochloric acid (FeCl3-HCl) solution. The etched wire was then used for LPME as the organic solvent holder. After solvent coating, the wire was directly exposed to a water sample for extraction of polycyclic aromatic hydrocarbons (PAHs), which were then subjected to thermal desorption in the injector of a gas chromatograph for gas chromatography-mass spectrometric (GC-MS) analysis. The parameters affecting PIN-LPME efficiencies (i.e., extraction solvent, solvent coating mode and time, stirring rate, extraction time and salting effect) were also investigated. Under the most favourable conditions, PIN-LPME-GC-MS exhibited high enrichment factors of between 70 and 349 for the 9 PAHs, low detection limits (between 0.006 and 0.058 ng mL−1), and good precision (with relative standard deviations ranging from 4.4% to 9.7%). The developed method was successfully applied for the extraction and determination of PAHs in tap, river and drain water samples. Good relative recoveries of the PAHs over the range of 84.3–101.9% were obtained with spiked genuine water samples.

The Purification of the Galvanic Industry Wastewater of Chromium(VI) Compounds Using Titanium(III) Chloride

The possibility of reduction of chromium(VI) compounds by solutions of titanium(III) chloride in hydrochloric acid has been investigated. It has been shown that the considered reagent possesses strong reductive properties over wide pH range. It has been proved that the efficiency of the reduction of chromium(VI) compounds with titanium(III) chloride in neutral medium is much higher than that when using sodium sulfite. It has been noted that in addition to the reduction properties, titanium compounds act as a highly efficient coagulant, thereby increasing the overall purification efficiency of the wastewater.

Selective leaching of valuable metals from laterite nickel ore with ammonium chloride-hydrochloric acid solution

Abstract During the recent years, selective leaching from laterite ore has gained considerable interest from the scientific community because of the growing demand of valuable metals including nickel and cobalt. However, high energy consumption and serious environmental pollution have been the major drawbacks of the current leaching methods, leading to a strong desire for the development of alternative approaches. Herein, we have successfully developed a clean method to selectively leach nickel from laterite ore using chlorination hydrometallurgical technology, which has a greatly reduced environmental impact and mild reaction requirements. In this work, ammonium chloride solution was used as the chlorination agent and the process was achieved under 2 M of hydrochloric acid, 3 M of ammonium chloride and a liquid/solid ratio of 6:1 (mL/g) at 90 °C for 90 min. Notably, the process resulted in a good yield, with nickel (87.7%), cobalt (75.1%), manganese (95.6%), and iron (only 21.1%). The leaching mechanism was demonstrated by the analysis of XRD pattern of leaching residue and raw ore, suggesting that chloride ions are beneficial to the dissolution of goethite mineral in nickel laterite. When comparing with other chloride solutions which exhibit high leaching in weak acid, ammonium chloride has demonstrated a promising ability to activate hydrogen ion, as evidenced in the simulation result of OLI system. The reusability of ammonia chloride in leaching raffinate showed that this method has great potential for eco-friendly and practical industrial application toward sustainable refining of valuable metals from laterite nickel ores.

Monosodium glutamate for simple photometric iron analysis

Simple photometric method for iron analysis using monosodium glutamate (MSG) was proposed. The method could be used as an alternative method, which was technically simple, economic, quantitative, readily available, scientifically sound and environmental friendly. Rapid reaction of iron (III) with glutamate in sodium chloride-hydrochloric acid buffer (pH 2) to form red-brown complex was served as a basis in the photometric determination, which obeyed the range of iron (III) concentration 1.6 – 80 µg/ml. This method could be applied to determine iron concentration in soil with satisfactory results (accuracy and precision) compared to other photometric and atomic absorption spectrometry results.

Hydrogen Generation through Cuprous Chloride-Hydrochloric Acid Electrolysis

Due to fast industrialization the consumption as well as the cost of fossil fuels like petrol, diesel etc in the world is rising enormously leading to the generation of greenhouse gases like carbon monoxide, carbon dioxide etc besides decreasing the availability of the above fuels. The emission of these greenhouse gases rises the globe’s temperature leading the earth to face many dangerous complications. In order to save the earth from effect of rise of temperature and also to have an eco-friendly alternate energy fuel especially for the transport sector, attention is being focused on the generation of hydrogen gas which meets the above situations. During the combustion of hydrogen gas it emits only the beneficial water vapour to the atmosphere. In this research paper investigation has been carried out through CuCl-HCl electrolysis with 1M CuCl anolyte and 6M HCl catholyte for the generation of hydrogen gas at 70oC at normal atmospheric pressure employing a double compartment electrolytic cell having a nafion cation exchange membrane-324. Anode was graphite and cathode was 0.30 mg cm-2 platinum coated graphite. At a current density of 250 A m-2 the current efficiency for the oxidation of CuCl to CuCl2 and the formation of hydrogen gas was nearly 100% and the rate of hydrogen liberation was found to be 2 l h-1. Voltage efficiency and energy consumption values are calculated and are found to be more encouraging since they are more economical with less energy operation. The formed CuCl2 was reduced back to CuCl anolyte by chemical reduction with copper powder in 6M HCl at 70oC and the regenerated CuCl anolyte was again used in the CuCl-HCl electrolysis.

Field testing of a magnesium oxide-lime-calcium chloride hydrochloric acid based filter

AbstractField trials of a MgO-Lime-CaCl2-HCl filter has been carried out to test the operation of the filter during actual user conditions. Water quality parameters like pH, TDS, Ca, Mg hardness, total alkalinity, SO4-2, Cl- were found to be within permissible limits in the water obtained from the filter except nitrate, whose concentration was above permissible limits in the raw ground water itself. The dosage of HCl had to be adjusted and fixed in the field trials. In comparison to the laboratory trials conducted earlier it was found that during the field trials there was on an average 6% reduction in the fluoride removal efficiency of the filter. Operational user problems of filter were found and were addressed in the village.

Impact of dietary nitrate supplementation via beetroot juice on exercising muscle vascular control in rats

Dietary nitrate (NO(3)(-)) supplementation, via its reduction to nitrite (NO(2)(-)) and subsequent conversion to nitric oxide (NO) and other reactive nitrogen intermediates, reduces blood pressure and the O(2) cost of submaximal exercise in humans. Despite these observations, the effects of dietary NO(3)(-) supplementation on skeletal muscle vascular control during locomotory exercise remain unknown. We tested the hypotheses that dietary NO(3)(-) supplementation via beetroot juice (BR) would reduce mean arterial pressure (MAP) and increase hindlimb muscle blood flow in the exercising rat. Male Sprague-Dawley rats (3-6 months) were administered either NO(3)(-) (via beetroot juice; 1 mmol kg(-1) day(-1), BR n = 8) or untreated (control, n = 11) tap water for 5 days. MAP and hindlimb skeletal muscle blood flow and vascular conductance (radiolabelled microsphere infusions) were measured during submaximal treadmill running (20 m min(-1), 5% grade). BR resulted in significantly lower exercising MAP (control: 137 ± 3, BR: 127 ± 4 mmHg, P < 0.05) and blood [lactate] (control: 2.6 ± 0.3, BR: 1.9 ± 0.2 mm, P < 0.05) compared to control. Total exercising hindlimb skeletal muscle blood flow (control: 108 ± 8, BR: 150 ± 11 ml min(-1) (100 g)(-1), P < 0.05) and vascular conductance (control: 0.78 ± 0.05, BR: 1.16 ± 0.10 ml min(-1) (100 g)(-1) mmHg(-1), P < 0.05) were greater in rats that received BR compared to control. The relative differences in blood flow and vascular conductance for the 28 individual hindlimb muscles and muscle parts correlated positively with their percentage type IIb + d/x muscle fibres (blood flow: r = 0.74, vascular conductance: r = 0.71, P < 0.01 for both). These data support the hypothesis that NO(3)(-) supplementation improves vascular control and elevates skeletal muscle O(2) delivery during exercise predominantly in fast-twitch type II muscles, and provide a potential mechanism by which NO(3)(-) supplementation improves metabolic control.

Synthesis and crystal structure of the salt of the protonated thiamine cation with the palladium(II) tetrachloride anion [HTA]2[PdCl4]Cl2 · 2H2O

The reaction of thiamine chloride hydrochloride with a solution of palladium chloride in hydrochloric acid gave a protonated thiamine salt [HTA]2[PdCl4]Cl2 · 2H2O (I) (TA is 4-methyl-3-[(2′-methyl-4′-amino-3′,4′-dihydropyrimidinyl-5′)methyl]-5-(2-hydroxyethyl)thiazolium cation, C12H16N3O2S). The crystal structure of I was determined by X-ray diffraction. The crystals are triclinic: a = 11.459(8) A, b = 12.239(8) A, c = 6.910(1) A, α = 103.24(3)°, β = 76.95(3)°, γ = 106.04(3)°, Z = 2, space group P $\bar 1$ . The structural units of I are doubly charged [HTA]2+ cations, [PdCl4]2− and Cl− anions, and crystallization water molecules combined by hydrogen bonds and electrostatic interactions. The planar thiazolium and pyrimidine rings are in the F conformation, Φt = 1.0°, Φp = −86.6°, and the dihedral angle between the planes is 85.5°. The torsion angles of the hydroxyethyl group are as follows: C(9)C(10)C(11)O(1), 175.6°; S(1)C(9)C(10)C(11), 33.2°; it is involved in the hydrogen bond with the free Cl− anion. The sulfur atom forms a short (3.052 A) intermolecular S-Cl contact with the chlorine atom of the [PdCl4]2− anion, which forms supramolecular chains.

P‐Nitrobenzyl protection for cysteine and selenocysteine: A more stable alternative to the acetamidomethyl group

This study evaluated the acidic lability of the acetamidomethyl (Acm), trimethylacetamidomethyl (Tacm), and the p-nitrobenzyl (pNB) as protecting groups for cysteine and selenocysteine (Sec) during the tert-butyloxycarbonyl (Boc)-chemistry solid-phase peptide synthesis of oxytocin (OT). Two novel Sec building blocks (Nalpha-tert-butyloxycarbonyl-Se(acetamidomethyl)-L-selenocysteine (Boc-L-Sec(Acm)-OH) and Nalpha-tert-butyloxycarbonyl-S(4-nitrobenzyl)-L-selenocysteine (Boc-L-Sec(pNB)-OH)) were developed for this study. Six partially protected thio- and seleno-OT analogues were synthesized, purified, and exposed to neat trifluoroacetic acid (TFA) at temperatures of 25, 40, 50, and 60 degrees C for 1 h, and HF treatment at 0 degrees C for 1 h. Significant losses were observed for the Acm and Tacm group in TFA at temperatures greater than 25 degrees C and during HF treatment at 0 degrees C, whereas the pNB group remained intact. Removal of the pNB was achieved via reduction to the p-aminobenzyl group either with zinc in acetic acid in solution or via tin chloride in hydrochloric acid on solid support, followed by oxidative cleavage with iodine yielding the corresponding disulfide or diselenide bond. No major side reactions were observed. This study confirms the occasionally described Acm instability and underpins the development of the pNB group as an alternative for cysteine and Sec protection.

H2OT][PdCl4], a salt of the protonated oxythiamine cation with the tetrachloropalladate(II) tetrachloride anion synthesis and crystal structure

The interaction of oxythiamine chloride hydrochloride with a solution of palladium chloride in hydrochloric acid affords a salt of protonated oxythiamine (H 2 OT )( PdCl 4 ) ( I ) (HOT is 4-methyl-3-((2'-methyl- 4'-oxo-3',4'-dihydropyrimidinyl-5')methyl)-5-(2-hydroxyethyl)thiazolium, C 12 H 16 N 3 O 2 S + ). The crystal struc- ture of salt I is determined by X-ray diffraction analysis. The crystals are monoclinic: a = 9.474(3) A, b = 13.822(2) A, c = 13.626(4) A, β = 93.42(2)° , V = 1781.2(3) A 3 , Z = 4, space group e 2 1 / n . The structural units of salt I are doubly-charged cations ( H 2 OT ) 2+ and anions ( PdCl 4 ) 2- joined by hydrogen bonds and electrostatic interaction into dimeric supermolecules. The thiazolium and pyrimidine rings in the cation are planar (the dihe- dral angle between the planes is 89.6° ) and oriented relative to the linking methylene center to form torsion angles Φ t = 64.9° and Φ  = 49.9° characteristic of the V ' conformation.

CrossRef Listing of Deleted DOIs

Carefully sized and characterized chalcopyrite concentrates were produced from eleven different geographical localities, and were subsequently leached in both ferric chloride-hydrochloric acid and ferric sulfate-sulfuric acid media. When the leaching rates were corrected for the amount of CuFeS2 in the particular sample, similar leaching rates (±50 pet) were observed for all eleven chalcopyrites under all experimental conditions. Furthermore, all the relatively pure chalcopyrites leached according to the same reaction and yielded >95 pet elemental sulfur as a sulfidic reaction product. In light of the current experimental observations, various reasons are offered for the order of magnitude variations in the chalcopyrite leaching rates often reported in the literature.

Hydrogen Bonding and Structure of Ba2Ru2Cl10O×10H2O.

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Hydrogen bonding and structure of Ba2Ru2Cl10O·10H2O

Dibarium micro-oxido-bis[pentachloridoruthenate(IV)] decahydrate, Ba(2)Ru(2)Cl(10)O.10H(2)O, has been prepared from ruthenium(III) chloride and barium chloride in hydrochloric acid. It crystallizes in the monoclinic system (space group C2/c). The structure consists of alternating layers of [Ru(2)Cl(10)O](4-) and [Ba(H(2)O)(7)](2+) complex ions along the a direction. The O atom bonded to ruthenium occupies the 4e site, with 1 symmetry, while the other atoms occupy general 8f sites. The overall structure is held together by O-H...O hydrogen bonds and O-H...Cl dipole-dipole interactions.

Reductive Coupling Reactions of 2-Nitrochalcones and their β-Hydroxy-analogues: New Syntheses of 2-Arylquinoline and 2-Aryl-4-hydroxyquinoline Derivatives

A one-pot synthesis of novel 2-arylquinolines and 2-aryl-4-hydroxyquinolines was developed from the intramolecular reductive coupling reactions of 2-nitrochalcones and 3-hydroxy-1-phenyl-3-(2-nitrophenyl)-2-propen-1-ones. Depending on the reduction method and on the presence of electron donating substituents on the A ring of 2-nitrochalcones one can modulate the formation of 2-arylquinolines, their N-oxides, and of 2-aminochalcones. The reduction of 3-hydroxy-1-(2-hydroxyphenyl)-3-(2-nitrophenyl)-2-propen-1-ones with stannous chloride in hydrochloric acid gave 2′-aminoflavones and with ammonium formate and Pd/C yielded 2-(2-hydroxyaryl)-4-hydroxyquinolines.

Synthesis of Rutile (α-TiO2) Nanocrystals with Controlled Size and Shape by Low-Temperature Hydrolysis: Effects of Solvent Composition

A new methodology was developed to synthesize uniform rutile (α-TiO2) nanocrystals by the thermohydrolysis of titanium(IV) chloride in hydrochloric acid−alcohol aqueous solutions at 40−90 °C. Depending on the acidity, the solvent used, and the aging temperature, rod-shaped rutile nanocrystals in sizes ranging from ∼100 nm to 800 nm were obtained. Nanocrystal size and shape are shown to be strongly and systematically related to the type and the concentration of alcohol used in the alcohol−water solvent, as well as the presence or absence of both cationic and anionic surfactants. No other titania phases, such as anatase or brookite, were detected using X-ray diffraction, transmission electron microscopy, and Raman spectroscopy.

Highly sensitive extractive spectrophotometric determination of palladium(II) in synthetic mixtures and hydrogenation catalysts using benzildithiosemicarbazone.

A simple and highly sensitive method was developed for the extractive-spectrophotometric determination of palladium with benzilidithiosemicarbazone. The metal ion formed a reddish brown complex with benzildithiosemicarbazone in a potassium chloride-hydrochloric acid buffer of pH 2.5, which was easily extractable into methyl isobutyl ketone. The 1:1 complex showed the maximum absorbance at 395 nm with a Beer's law range of 0.25-3.5 ppm. The molar absorptivity and Sandell's sensitivity were found to be 3.018 x 10(4) dm3 mol(-1) cm(-1) and 0.0035 microg cm(-2), respectively. The correlation coefficient of the Pd(II)-BDTSC complex was 0.998, which indicated an excellent linearity between the two variables. The repeatability of the method was checked by finding the relative standard deviation (RSD) (n = 10), which was 0.46%. The instability constant of the complex calculated from Edmond and Birnbaum's method was 2.41 x 10(-5), that of Asmus' method is 2.53 x 10(-5) at room temperature. The interfering effects of various cations and anions were studied. The proposed method was successfully applied to the determination of palladium(II) in synthetic mixtures and hydrogenation catalysts. The validity of the method was tested by comparing the results with those obtained using an atomic absorption spectrophotometer.

Syntheses and crystal structures of SmIII and ThIV complexes with macrocyclic cavitand cucurbituril

Slow evaporation of solutions of samarium nitrate and thorium chloride in hydrochloric acid containing the macrocyclic cavitand cucurbituril (C36H36N24O12) afforded crystals of the [{Sm(H2O)5(NO3)}2(C36H36N24O12)](NO3)4·6.5H2O and [{Th(H2O)5Cl}2(C36H36N24O12)]Cl6·13H2O complexes, respectively. The [Sm(C36H36N24O12)(H2O)5(SO4)][Sm(H2O)5(SO4)2]·17H2O complex was generated upon heating (130 °C) of a mixture of samarium sulfate, cucurbituril, and water in a sealed tube. X-ray diffraction analysis demonstrated that the metal atoms in these complexes are bound to the portal oxygen atoms of the cucurbituril molecules. In addition, the portal oxygen atoms of cucurbituril are linked to the coordinated H2O molecules via hydrogen bonds.

The effect of tetrahedrite composition on its leaching behaviour in FeCl 3NaClHCl solutions

The effect of tetrahedrite composition on its behaviour during leaching with ferric chloride-sodium chloride-hydrochloric acid solutions was investigated. This study used three natural samples of tetrahedrite with different compositions, which were analyzed by X-Ray diffraction and electron microprobe. The shrinking core model was applied to describe the leaching behaviour of the tetrahedrite samples and the results show that the iron content of the solid affects the leaching rate. In fact, increases in iron content increase the leaching rate of tetrahedrite and the results are interpreted in terms of the semiconductor theory.

Ebenaceae extractives. Part 11. The synthesis of 7-methyljuglone. A re-examination

The Friedel–Crafts reaction between maleic anhydride and 4-chloro-3-methylphenol yields, besides 8-chloro-5-hydroxy-7-methylnaphthoquinone 1, helminthosporin 5 and its 8-chloro derivative 6 and, after methylation, methyl (E)-β-(5-chloro-2-methoxy-4-methylbenzoyl)acrylate 4. Treatment of the chloronaphthoquinone 1 with tin(II) chloride in hydrochloric acid and tetrahydrofuran followed by iron(III) chloride converts it efficiently into 7-methyljuglone 2.

Electrodeposition of copper from pure cupric chloride hydrochloric acid solutions

Electrodeposition from CuCl2–HCl media has been investigated to establish a clean and direct method of copper extraction from cupric chloride solutions purified by anion exchange. The major difficulties of the process – cathode corrosion, CuCl precipitation and roughness of the deposit – were taken into consideration. To prevent contamination, no chemical agents or additives were used in the electrolyte preparation. The workable range of electrolyte composition was approached from a computer aided stability study of the different aquo- and chloro-complex copper species. Experiments suggested that coordination of the fundamental electrolysis parameters can ensure acceptable copper deposits and current efficiencies. A special method of agitation proved effective in improving the conditions.