Excess Of Hydrochloric Acid Research Articles

Eggshell waste transformation to calcium chloride anhydride as food-grade additive and eggshell membranes as enzyme immobilization carrier

Abstract In continuation of our efforts to fully utilize eggshell waste (ESW), here we report the possibility of ESW transformation to calcium chloride (CaCl2) anhydride of food-grade additive purity and eggshell membranes (ESMs) as potential enzyme immobilization carriers. ESW chemical transformation by 5% (w/v) hydrochloric acid to CaCl2 solution and ESM completely devoid of the remnants of ESW calcium carbonate was performed in the constructed 15 L batch reactor during 4 h at room temperature, followed by separation of ESM from CaCl2 solution by filtration. ESW-derived CaCl2 solution containing the excess hydrochloric acid was neutralized by adding calcium hydroxide, concentrated to approximately 1/8th of volume, and spray dried. Separated ESM was washed with water and acetone, dried, and ground to a size of less than 0.5 mm. The ESW transformation process produced 102.42 ± 3.31 g of CaCl2 anhydrous and 2.48 ± 0.28 g of ESM per 100 g of ESW dry matter. ESW-derived CaCl2 fulfilled all criteria for food-grade additive, while obtained ESM showed their suitability for Burkholderia cepacia lipase immobilization by adsorption.

Transformation of eggshell waste to egg white protein solution, calcium chloride dihydrate, and eggshell membrane powder

Abstract The present study investigated the possibility of complete utilization of eggshell waste (ESW) transforming it to adherent egg white protein solution, calcium chloride dihydrate, and eggshell membranes (ESM). Adherent egg white protein solution was obtained by washing ESW three times with distilled water at 25°C, followed by filtration, and analyzed for the protein content and lysozyme activity. ESM and calcium chloride were obtained simultaneously by the exposure of washed eggshells to 5% hydrochloric acid treatment at 25°C for 3 h, followed by separation by filtration. The separated ESM were washed, dried, and milled to powder and analyzed for protein and lipid content. The calcium chloride solution was exposed to the neutralization of excess hydrochloric acid by calcium hydroxide, followed by evaporation to one-tenth of volume. Calcium chloride crystals were precipitated from the concentrated solution with acetone, separated by filtration, dried at 110°C, and analyzed for chemical composition and purity. The obtained results revealed that 100 g of ESW can be transformed to 1.61 ± 0.34 g of adherent white proteins containing 485,821 U of lysozyme activity, 2.84 ± 0.16 g of ESM powder, and 108.74 ± 3.62 g of calcium chloride dihydrate of high purity.

Синтез и антимикробная активность новых фосфорсодержащих производных пиридина

The directed synthesis of new pharmacophoric molecules is one of the urgent tasks of organic chemistry. A special place in this area is occupied by vital nitrogen-containing heterocycles and their derivatives, on the basis of which new promising precursors of drugs are created. For example, pyridinium salts are part of such well-known drugs as pyridoxine, mexidol and metadoxine. Phosphorus-containing pyridine derivatives, among which compounds with cytotoxic and antimicrobial properties have been identified, are also being actively studied now. Thus, the development of convenient approaches for obtaining new functional phosphorus-containing pyridine derivatives is an important and timely task. Special attention is paid to synthetic methods that correspond to the PASE (pot, atom and step economy) paradigm. Using this approach, we have synthesized hydrochlorides and tosylates of 4-bis(2-phenylethyl)chalcogenophosphoryl-pyridine, not described previously, by practically quantitative interaction of the available 4-bis(2-phenylethyl)chalcogenophosphorylpyridines with hydrochloric or 4-methylbenzenesulfonic acids at room temperature or slight heating (40-45 °C). The reaction proceeds regioselectively on the nitrogen atom of the base pyridine. The second reaction center in the 4-bis(2-phenylethyl)chalcogenophosphorylpyridine molecule, chalcogenophosphoryl group, does not participate in the studied process, even when using an excess of hydrochloric acid. The starting 4-bis(2-phenylethyl)chalcogenophosphorylpyridines are easily obtained on the basis of the original reaction of pyridine with secondary phosphine chalcogenides with the assistance of electron-deficient acetylenes. Using the example of microorganisms of different taxonomic groups: Bacillus subtilis B-406, Enterococcus durans B-603, Penicillium citreo-viride F-1777, Escherichia coli B-1238, we have found that the target hydrochlorides and tosylates of 4-bis(2-phenylethyl)chalcogenophosphorylpyridine exhibit pronounced antimicrobial activity against non-spore gram-positive microorganisms.

A novel method of nicotine quantification in electronic cigarette liquids and aerosols.

The electronic cigarette (e-cigarette) has emerged as popular electronic nicotine delivery devices (ENDs). However, the general safety and validity of e-cigarettes for nicotine delivery efficacy are still not well understood. This study developed a new method for efficient measurement of nicotine levels in both the liquids (e-liquids) used in e-cigarettes and the aerosols generated from the e-cigarettes. Protonation of the pyrrolidine nitrogen of nicotine molecules by addition of excess hydrochloric acid affords an aminium salt that is readily quantified by Fourier transform ion cyclotron mass spectrometry (FT-ICR-MS). The kinetics of nicotine protonation was studied using 1H NMR spectroscopy. Quantitative analyses of nicotine in commercial e-liquids and in the corresponding derived e-cigarette aerosols were carried out using direct infusion FT-ICR-MS. The 1H NMR study of nicotine protonation revealed a first order reaction and an activation energy of 30.05 kJ mol-1. The nicotine levels measured in the commercial e-liquids were within a wide and highly variable range of -2.94% to +25.20% around the manufacturer's stated values. The results indicated considerable differences between the measured levels and the advertised levels of nicotine in the e-liquids. The nicotine quantity measured in aerosols increased linearly both with nicotine level in e-liquids (same number of puffs) and with number of puffs (same e-liquids). These data show that quality control of e-liquids and use characteristics are major variables in efficacy of nicotine delivery.

Comments on “Crystal growth, spectral, optical, and thermal characterization of glycyl-l-alanine hydrochloride (GLAH) single crystal”

The authors of the title paper (J Therm Anal Calorim 2012,110:873–878) report to have grown a dipeptide hydrochloride crystal namely glycyl-l-alanine hydrochloride by the slow evaporation of an aqueous solution containing stoichiometric amounts of l-alanine and glycine and an excess of hydrochloric acid. In this letter, we prove that no such dipeptide hydrochloride can be crystallized simply by mixing two amino acids in aqueous hydrochloric acid.

White Esophageal Mucosa and Black Gastric Mucosa: Upper Gastrointestinal Injury Due to Hydrochloric Acid Ingestion

Caustic ingestion can cause severe injury to the esophagus and stomach. The severity and extent of esophageal and gastric damage resulting from caustic ingestion depend upon several factors. In the present report, we describe the case of a 55-year-old schizophrenic man who drank 400 mL of hydrochloric acid. Endoscopy indicated the presence of white esophageal mucosa and black gastric mucosa, which is evident in the images taken before and after ingestion (Fig. 1). Fig. 1 Endoscopic findings. (A) Initial esophagoscopy. No abnormality is noted during the initial examination of the esophageal mucosa. (B) Initial gastroscopy. No abnormality is seen during the initial examination of the gastric mucosa, except for linear erythema. ... Acid ingestion typically produces a superficial coagulation necrosis that results in thrombosis of underlying mucosal blood vessels and consolidation of connective tissue, thereby forming a protective eschar.1 Because acid solutions cause pain upon contact with the oropharynx, the amount of acid ingested tends to be limited. However, in the present case, the patient had schizophrenia, and despite experiencing pain, he drank 400 mL of hydrochloric acid. We believe that the excess hydrochloric acid injured the esophageal mucosa and subsequently turned the esophagus white, due to the development of mucosal edema, exudates, and superficial coagulation necrosis. Typically, when acid is ingested, it flows along the lesser curvature of the stomach towards the pylorus, and pylorospasm impairs emptying into the duodenum, producing stagnation and injury that is particularly prominent in the antrum.2 However, in the present case, excess acid stagnated in the stomach, and as a result, we believe that the gastric mucosa was damaged up to the transmural layer, causing the black coloring of the mucosa. The severity and extent of esophageal and gastric damage resulting from caustic ingestion depend upon three major factors: corrosive properties of the ingested substance; duration of contact with the mucosa; and the amount, concentration, and physical form (solid or liquid) of the agent.3,4 Most ingestions occur in children, whereas the other cases involve psychotic, suicidal, or alcoholic subjects.5 The present case was a subject who was both psychotic and suicidal. Caustic ingestion is usually accidental in children under the age of 5 years and intentional in adults and adolescents. Highly concentrated acids (hydrochloric, sulfuric, and phosphoric acid) present in toilet bowl or swimming pool cleaners, anti-rust compounds, or in battery fluid are less frequently ingested than alkalis.4 When acid remains on the esophagus, burns can occur within 4 hours and perforation can occur within 6 hours; in such cases, urgent endoscopy is indicated. In the present case, we performed esophagogastroduodenoscopy (EGD) within 4 hours of ingestion. Alkali ingestions typically damage the esophagus to a greater extent than the stomach or duodenum, whereas acids cause more severe gastric injury. A study comparing outcomes of acid or alkali ingestion found that the outcomes were worse overall for those who ingested acid.6 Such patients had significantly more severe mucosal injury, were more likely to be hospitalized in the intensive care unit, were more likely to have systemic complications or perforation, and had higher mortality. Caustic injuries to the gastrointestinal tract are classified pathologically, similarly to burns of the skin. First degree injury results from superficial mucosal damage and is characterized by the presence of focal or diffuse erythema, edema, and hemorrhage. The mucosal lining subsequently sloughs without scar formation. Second-degree injury is characterized by the presence of mucosal and submucosal damage, ulcerations, exudates, and vesicle formation. Eventually, granulation tissue develops, followed by a fibroblastic reaction that produces a scar and possible stricture. Third degree injury is transmural and is characterized by the presence of deep ulcers along with black discoloration and perforation of the wall. Endoscopy should be performed as soon as possible—ideally within 24 hours—in order to assess the magnitude and extent of injury, according to the grading system. Subsequent management is determined based on the results of endoscopy. Patients suspected of having serious ingestions (based on history, symptoms, or endoscopic findings) should generally be treated in a surgical or medical intensive care unit for the management of acute, life-threatening complications of injury (mediastinitis, peritonitis, respiratory distress, shock, and metabolic disorder) and to decrease the risk of developing late esophageal strictures. Each patient should be evaluated individually since the clinical picture varies widely, and signs and symptoms alone are an unreliable guide to injury.7 In the case of severe caustic damage, endoscopy should be performed within 24 hours. However, endoscopy is not needed for all patients and may be deferred at the physician's discretion. We experienced an interesting case of acid ingestion wherein endoscopy indicated the presence of a white esophagus and black gastric mucosa; we provide a description of this case with images, along with a review of the literature.

Electrical properties of organic–inorganic semiconductor heterojunction

Conducting polyaniline (PANI) was prepared by chemical oxidation polymerization in the presence of excess hydrochloric acid. Zinc sulfide (ZnS) thin films were deposited on glass substrates at the pressure of 10−5 mbar by thermal resistor evaporation technique. The solution of conducting PANI has been printed on pellet of ZnS using spin-coating technique. I–V characteristics of ZnS thin film and printed conducting PANI have been recorded at room temperature. The results indicated that I–V of conducting PANI shows non-ohmic behavior and I–V characteristic of conducting PANI printed ZnS, a PANI–ZnS heterojunction, shows the rectification effect and confirms that a diode can be fabricated by using simple technique.

Study of TATP: Formation of New Chloroderivates of Triacetone Triperoxide

AbstractThe existence of two new types of chloroderivates of cyclic acetone peroxides – 3‐(chloromethyl)‐3,6,6,9,9‐pentamethyl‐1,2,4,5,7,8‐hexoxonane and 3,6‐bis(chloromethyl)‐3,6,9,9‐tetramethyl‐1,2,4,5,7,8‐hexoxonane was proved by HPLC/MS/MS and NMR in the reaction products when acetone and hydrogen peroxide are mixed in the presence of excess hydrochloric acid (molar ratio hydrochloric acid to acetone nc/na=2.5). The details of analysis, and the conditions under which these asymmetric chloroderivates of cyclic peroxides form, are described.

Dissolution of periclase in excess of hydrochloric acid: Study of inhibiting effect of acid concentration on the dissolution rate

Kinetics of the dissolution of particulate polycrystalline MgO in excess of hydrochloric acid were investigated, with special regard to the effect of activity of H+ ions, temperature and particle size. The results are presented in terms of the shrinking particle model. The overall process is controlled by the chemical reaction of MgO with H+ ions at the liquid–solid interface. The apparent activation energy was 58 kJ mol−1. Acid concentration (from 0.5 M to 5.1 M) was surprisingly found to have a decelerating effect on the dissolution rate of MgO, resulting in negative values of reaction order for H+ ions (from −0.16 to −0.18). We conclude that the regime studied here, characterised by decrease in the dissolution rate of MgO with an increase in H+ activity, occurs under far from mass-transfer control conditions in the solutions with low Mg2+:H+ molar ratio.

Crystallographic report: [N,N′-Bis-(6-methylpyrid-2-ylium)-(1R,2R)-1,2-diaminocyclohexane] bis-[(p-cymene)- trichlororuthenate(II)

The chiral compound (H2cydiampy)[RuCl3(p-cymene)]2 has been obtained in high yield by treating [RuCl2(p-cymene)]2 with an excess of hydrochloric acid in the presence of one equivalent of N,N′-bis-(6-methylpyrid-2-yl)-(1R,2R)-1,2-diaminocyclohexane (cydiampy). It crystallizes in the chiral tetragonal space group P43212, with half of the atoms of the dication related to the other half by a crystallographic C2 axis that also makes equivalent the two anionic metal moieties. Copyright © 2005 John Wiley & Sons, Ltd.

A Solvent‐Free Synthesis of (Dichloroiodo)arenes from Iodoarenes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

A solvent-free synthesis of (dichloroiodo)arenes from iodoarenes

An efficient solid-state oxidation of iodoarenes, ArI, is described using the urea–hydrogen peroxide adduct (UHP), a stable, inexpensive, and easily handled oxidant. The reactions were complete in 15 min at 85 °C. The melts thus obtained were reacted with excess hydrochloric acid to afford crude (dichloroiodo)arenes, ArICl 2, in 64–98% yields.

Positional isomerization of quinine and quinidine via rhodium on alumina catalysis: practical one-step synthesis of Δ 3,10-isoquinine and Δ 3,10-isoquinidine

The synthesis of Δ 3,10-isoquinine ( 5 Z , 5 E ) and Δ 3,10-isoquinidine ( 6 Z , 6 E ) was achieved in one-step through positional isomerization of the terminal alkene in the parent cinchona alkaloids using catalytic amounts of 5% Rh/Al 2O 3 and excess hydrochloric acid in refluxing 50% aqueous EtOH. The products were obtained in good yields as a mixture of E and Z geometric isomers and fully characterized using spectroscopic methods.

Determination of Free Lime in Clinker and Cement by Iodometry. An Undergraduate Experiment in Redox Titrimetry

An interesting application of the determination of acid by iodometry is proposed for the determination of free lime in clinker and cement. Free lime in the sample is first extracted with nonaqueous ethylene glycol at 70 °C for 15 minutes. The filtered suspension is reacted with a known excess of hydrochloric acid. The excess acid is determined by iodometry. The proposed method is better than the classical British Standard method in terms of speed, sensitivity, and precision. It is an excellent addition to the undergraduate analytical experiments currently available, where within a single experiment students can make use of analytical techniques such as nonaqueous extraction, filtration, and iodometry as well as some statistical methods in analysis. It also gives students an opportunity to become familiar with the cement industry. The method is suitable to be adopted for the analysis of free lime in clinker and cement in a cement plant or a commercial laboratory.

A fundamental model of platinum impregnation onto alumina

Refined forms of the revised physical adsorption Model (RPA) proposed by Agashe and Regalbuto (J. Coll. Interf. Sci. 185 (1997) 174) and a proton transfer model by Park and Regalbuto (J. Coll. Interf. Sci. 175 (1995) 239) were employed to model five sets of data of platinum (from chloroplatinic acid, CPA) adsorption over alumina found in the literature. Through a detailed individual consideration of ionic strength, which is the main cause of adsorption retardation at pH extremes, the results were further improved such that adsorption could be predicted a priori to a very reasonable degree without adjustable parameters. A comprehensive simulation of uptake as a function of initial platinum concentration, initial solution pH and the surface loading (amount of oxide surface per solution volume) shows that the model reflects all important features of adsorption typically seen in experimental studies and illustrates how it can be used to optimize the design of a catalyst impregnation. Over a range of low–moderate surface loadings corresponding to wet impregnation of relatively small amounts of oxide in excess solution, the diprotic chloroplatinic acid itself creates favorable electrostatic conditions and little or no pH adjustment is required to obtain full uptake of the available platinum from the solution (high “uptake efficiency”). At higher surface loadings corresponding to dry impregnation or pore volume filling that are more representative of industrial catalyst preparation recipes, however, the pH buffering effect of the oxide becomes so pronounced that additional acid is required to sufficiently charge the oxide surface and facilitate full platinum uptake. This offers a new interpretation of the often-cited necessity of excess hydrochloric acid in pellet impregnation at high surface loading, where a homogeneous metal distribution in the pellet is desired; the protons rather than the chloride ions may be the important factor. Furthermore, excessive amounts of platinum in solution (corresponding to an excess of a monolayer of Pt complexes at the surface) lead to self-inhibition based on high ionic strength in the solution and a dramatic drop in noble metal efficiency.

Quantitative determination of olefin oxide, chlorohydrin, and cyclocarbonate in the presence of each other

A procedure was developed for the quantitative determination of olefin oxide, chlorohydrin, and cyclocarbonate simultaneously present in the reaction mixture of the synthesis of cyclocarbonate from olefin oxide and CO2. To determine olefin oxide, an acetone solution of hydrochloric acid was added to a portion of the reaction mixture, and the excess of hydrochloric acid was titrated with an aqueous solution of potassium hydroxide with visual detection. The concentrations of chlorohydrin and cyclocarbonate were calculated from the data of the potentiometric titration of the same solution to which excess potassium hydroxide was added.

Rhodium-Catalyzed Synthesis of Naphthalene Derivatives Through Cyclodimerization of Arylalkynes⋆

RhCl(PPh3)3 in the presence of excess hydrochloric acid and azobenzene in refluxing 1-pentanol catalyzes the cyclodimerization of arylalkynes to 1,2,3-substituted naphthalene derivatives. This enables an easy access to 1,2,3-triphenylnaphthalene (1), 7-methoxy-1,2,3-tris(p-methoxyphenyl)naphthalene (2), 7-methyl-1,2,3-tris(p-methylphenyl)naphthalene (3), and 7-nitro-3-(p-nitrophenyl)-1,2-diphenylnaphthalene (4). A co-cyclodimerization of tolan with 4-octyne affords 3-phenyl-1,2-dipropylnaphthalene (5). The structure of 4 was resolved by single-crystal X-ray structural analysis. The rate of formation of 1 is first-order with respect to tolan and RhCl(PPh3)3 and exhibits activation parameters of ΔH‡ = 94.7 ± 10 kJ mol−1 and ΔS‡ = 36 ± 6 J K−1mol−1. Replacing HCl by HBr and HI decreases the rate by 28 and 55%, respectively. Although naphthalene formation occurs also in the absence of azobenzene, its presence stabilizes the catalyst, accelerates the reaction, and inhibits formation of 1-chlorostilbene, which is the major by-product. When RhCl(PCy3)2 is used as the catalyst, naphthalene formation even in the absence of azobenzene is highly selective, but proceeds much slower. No reaction is observed in non-protic solvents.

Improvements to two routine methods for calcium carbonate determination in soils

In the course of routine analytical work, wide discrepancies were noted between results from alternative, established procedures for measuring calcium carbonate (CaCO3) in soils. In one procedure (Method I), the CaCO3 content is calculated from the weight of CO2 lost after treating a sample with excess hydrochloric acid. Results of an investigation using this procedure in our laboratory tended to be inaccurate and poorly reproducible. The method was therefore modified by using as the reaction vessel a plastic vial with pin‐holes in its lid, instead of a glass Erlenmeyer flask with a stopper removed at intervals, to let CO2 escape. Further, the weighed soil sample was placed in a disposable cup inside the vial of acid, instead of being weighed and transferred. These modifications greatly improved accuracy and reproducibility of results obtained by Method I. In another procedure, the CaCO3 content was calculated from the pH of a suspension of the soil in dilute acetic acid (Method II). This method tends to give results appreciably greater than zero for acidic soils containing no free lime. This undesirable tendency was reduced after Method II was modified by calibrating it against soils spiked with known amounts of CaCO3, instead of against CaCO3 alone. As a result of the modifications, agreement between results for soils analyzed by both methods was greatly improved. Method I is considered more suitable for soils with appreciable free lime, or for liming materials, and Method II for soils with low CaCO3 content (.5% or less).

Control of the surface charge density of colloidal silica by sodium hydroxide in salt-freeand low-salt dispersions

Electrical conductivity measurements and conductometric titrations were performed on dilute salt-free aqueous dispersion of a colloidal silica (diameter: 0.11\ifmmode\pm\else\textpm\fi{}0.01\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}6}$nm) whose charge number can be varied with the quantity of coexisting sodium hydroxide. In the absence of sodium hydroxide, the silica particle had an effective (net) surface charge density ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{e}}$ of 8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}8}$nC ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$. Titrations by hydrochloric acid were performed in the presence of sodium hydroxide. When the NaOH concentration was sufficiently high, the titration curve could be divided into three regions with regard to slope values. These regions could be ascribed to titrations of excess sodium hydroxide, ionizable surface groups having Na ions as counterions, and excess hydrochloric acid. The analytical surface charge density ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{a}}$, estimated from the titration curves, increased with increasing [NaOH]. It was found that the concentrations of Na and OH ions in excess were negligible when the [NaOH] was smaller than 2.5\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}4}$nM and the volume fraction of the silica, \ensuremath{\varphi}, was larger than 2.6\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}3}$. The value of ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{a}}$ at this threshold was 1.8\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}5}$nC ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$. Under these conditions we could control the ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{a}}$ value by varying [NaOH]. The present system provides larger possibilities in studying the influence of charge density on the physico-chemical properties of ionic colloidal systems. Viscosity measurements were performed for salt-free and low-salt dispersions at [NaOH]'s where its excess concentration was found to be negligible. The ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{a}}$ dependence of the viscosity was in good agreement with previous results obtained from ionic latices having various ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{a}}$'s. A relationship between the effective charge density at an infinite dilution, ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{e}\mathrm{|}\mathrm{\ensuremath{\varphi}}\mathrm{=}0}$, and ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{a}}$ was examined for latex systems. An empirical relation, ln ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{e}\mathrm{|}\mathrm{\ensuremath{\varphi}}\mathrm{=}0}$=0.49 ln ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{a}}$-1.0, was obtained by using ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{e}\mathrm{|}\mathrm{\ensuremath{\varphi}}\mathrm{=}0}$ values determined by the conductivity for latices with various ${\mathrm{\ensuremath{\sigma}}}_{\mathrm{a}}$'s from 0.21\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}6}$ to 5.6\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}6}$nC ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}2}$. By assuming that this relation holds also for the silica system, viscosity data were analyzed. Satisfactory agreement was observed between the experimental value and Booth theoretical value on the first-order electroviscous effect.

Volatility of ammonium chloride over aqueous solutions to high temperatures

The chemical carryover of chloride in the water/steam cycles of power plants have been correlated with the expected ammonium chloride volatility in those plants using all-volatile treatment. The partitioning of ammonium chloride from aqueous solutions to the vapor phase was measured from 120 to 350 C. The experiments were performed in a platinum-lined autoclave from which samples of the liquid and vapor phases were withdrawn for analysis by ion chromatography, and acidimetric titration. The liquid-phase pH was maintained either with an excess of hydrochloric acid or by excess ammonia in the ammonium chloride solutions. The molal thermodynamic partitioning constants for NH[sub 4]Cl were calculated from the observed liquid- and vapor-phase concentrations, taking into account the known partitioning coefficients of HCl and NH[sub 3], as well as the known mean stoichiometric activity coefficients of the ionic species in the liquid phase. The partitioning constants for NH[sub 4]Cl, NH[sub 3], and HCl are represented as simple functions of temperature and water density. Some discussion is given of the relevance of these results to modeling the transport of chloride in power plants using ammonia to control the pH of the water/steam cycle.