Schreinemaker's Method Research Articles

Phase Equilibrium and Phase Diagram for the System of Benzene Dicarboxylic Acid + N-Methyl-2-pyrrolidone

The mutual solubility for ternary systems of terephthalic acid + isophthalic acid + N-methyl-2-pyrrolidone, phthalic acid + isophthalic acid + N-methyl-2-pyrrolidone, and phthalic acid + terephthalic acid + N-methyl-2-pyrrolidone were measured at 303.15 K and 313.15 K under normal pressure. Six phase diagrams were plotted on the basis of the measured solubility data. Two pure solids were formed for each system, and they were recognized by the method of Schreinemakers’ wet residue. Two crystalline adducts were formed, which were the adduct of isophthalic acid with N-methyl-2-pyrrolidone (named as N, isophthalic acid/N-methyl-2-pyrrolidone = 1:2 in mole ratio) and adduct of terephthalic acid with N-methyl-2-pyrrolidone (named as M, terephthalic acid/N-methyl-2-pyrrolidone = 1:2 in mole ratio). Each phase diagram exhibited only one eutectic point. The crystallization fields of phthalic acid, adduct N and adduct M were increased as the temperature increased. At the same temperature, the crystallization field of adduct M is the largest. In addition, the densities of the equilibrium liquid phase were obtained.

Measurement and calculation of solid–liquid phase equilibrium for ternary 4-chlorophthalic anhydride + 3-chlorophthalic anhydride + acetone system

The solid–liquid phase equilibrium for ternary system of 4-chlorophthalic anhydride+3-chlorophthalic anhydride+acetone was measured at different temperatures and the mutual solubility was obtained. Four isothermal phase diagrams were constructed according to the experimental solubility. There existed two pure solid phases at each temperature in the studied system, pure 4-chlorophthalic anhydride and pure 3-chlorophthalic anhydride, which were identified by the wet residue method of Schreinemakers’. The crystallization regions of the pure two solids increase with the decrease in temperature. The experimental solid–liquid phase equilibrium for ternary system was calculated using the Wilson and NRTL models, and the corresponding binary interaction parameters were obtained according to the solubility of binary system. The calculated results agree well with the experimental data at different temperature. Both the models give acceptable results for the investigated systems.

High‐Pbehavior of anorthite composition and some phase relations of the CaO‐Al2O3‐SiO2 system to the lower mantle of the Earth, and their geophysical implications

Multianvil experiments with long experimental durations have been made with the anorthite composition CaAl2Si2O8at pressure‐temperature (P‐T) conditions of 14–25 GPa and 1400–2400°C. At subsolidus conditions, these experiments demonstrated three phase assemblages, grossular (Gr) + kyanite (Ky) + stishovite (St) at ∼14 GPa, Gr + calcium‐alumino‐silicate phase (CAS) + St at ∼18 GPa, and CAS + CaSiO3‐perovskite (CaPv) + St at above ∼20 GPa, which are related by the reactions Gr + Ky = CAS + St and Gr + St = CAS + CaPv. Following the method of Schreinemakers, we combined our data with the literature data to deduce aP‐Tphase diagram for a portion of the CaO‐Al2O3‐SiO2system at subsolidus conditions, which subsequently helped to solve some long‐lasting discrepancies in the high‐Pbehavior of the compositions of anorthite and grossular. The crystal chemistry of the CAS and CaPv solid solutions was examined, and new substitution mechanisms were firmly established. Along the solidus, the melting reaction at ∼14 GPa is peritectic while that at ∼22 GPa is eutectic. For both pressures, St is the first phase to melt out and the melt is generally andesitic. For the An composition, its density starts to be significantly higher than the density of pyrolite at ∼2.5 GPa, a much lower pressure than that for the Or, Ab or Qtz composition (∼7.5–10 GPa), so that the An‐enriched continental crust material should readily plunge into the upper mantle.

Solid–liquid phase equilibrium for the ternary system urea phosphate + ammonium dihydrogen phosphate + water at 25 and 55 °C

The ternary system of urea phosphate+ammonium dihydrogen phosphate+water at 25 and 55°C was investigated by the method of isothermal solution saturation and moist residues. Solubility and density data of the system were determined experimentally, and corresponding phase diagrams were constructed on the basis of solubility data. The solid phase in this system was comfirmed by Schreinemaker's method of wet residue. The trajectories at different temperatures are approximately similar, and the crystallization regions of urea phosphate and ammonium dihydrogen phosphate increase as the temperature decreases. The solubility data, density, and the phase equilibrium diagrams for the ternary system can provide the fundamental basis for the preparation of urea phosphate in ammonium dihydrogen phosphate and urea phosphate aqueous mixtures.

Phase Diagrams for the Ternary Na2O−Al2O3−H2O System at (150 and 180) °C

The full alkali concentration range phase diagrams of the Na2O-Al2O3-H2O system were constructed at (150 and 180) degrees C. The compositions of the clear liquids and wet solid phases were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES), and the results show that, as the Na2O concentration increases, the Al2O3 solubility initially increases monotonically, to maximum values of 100 w (mass fraction) = 33.58 and 35.86 at (150 and 180) degrees C, respectively, and then decreases. At both temperatures, the solid phases were determined to be Al2O3 center dot H2O, Na2O center dot Al2O3 center dot 2.5H(2)O, Na2O center dot Al2O3, and NaOH by X-ray diffraction coupled with Schreinemaker's method. The phase diagrams indicate that, as the temperature increases, the Na2O center dot Al2O3 center dot 2.5H(2)O phase region shrinks, while that of the Na2O center dot Al2O3 phase expands.

Phase Diagram for the Na2O—Al2O3—H2O System at 130 °C.

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Phase Diagram for the Na2O−Al2O3−H2O System at 130 °C

A phase diagram for the Na2O-Al2O3-H2O system at 130 degrees C is presented in this paper using Schreinemaker's method. The compositions of the clear liquid and the wet solids were analyzed by inductively coupled plasma atomic emission spectrometry (ICP-AES). The equilibrium solids are aluminum hydroxide (Al2O3 center dot H2O), sodium aluminum hydroxide (Na2O center dot Al2O3 center dot 2.5H(2)O), and sodium aluminum oxide (Na2O center dot Al2O3) in the different alkali concentration regions.

Solubility isotherm and thermal analysis of the selenites of the three-component system La2O3-SeO2-H2O at 100°C

The solubility isotherm of the system La2O3—SeO2—H2O at 100°C was studied. The compounds of the three-component system were identified by the Schreinemakers method as well as by chemical and X-ray phase analyses. Simultaneous TG and DTA analyses of all compounds of the system were made by using a derivatograph. The mechanism of thermal decomposition was described.

Experimental phase relations of hydrous peridotites modelled in the system H2O-CaO-MgO-Al2O3,-SiO2

The hydration of peridotites modelled by the system H2O-CaO-MgO-Al2O3-SiO2 has been treated theoretically after the method of Schreinemakers, and has been investigated experimentally in the temperature range 700°–900° C and in the pressure range of 8–14 kbar. In the presence of excess forsterite and water, the garnet- to spinel-peridotite transition boundary intersects the chlorite dehydration boundary at an invariant point situated at 865±5° C and 15.2±0.3 kbar. At lower pressures, a model spinel lherzolite hydrates to both chlorite- and amphibole-bearing assemblages at an invariant point located at 825±10° C and 9.3±0.5 kbar. At even lower pressures the spinel-to plagioclase-peridotite transition boundary intersects the dehydration curve for amphibole+forsterite at an invariant point estimated to lie at 855±10° C and 6.5±0.5 kbar. Both chlorite and amphibole were characterized along their respective dehydration curves. Chlorite was found to shift continuously from clinochlore, with increasing temperature, to more aluminous compositions. Amphibole was found to be tremolitic with a maximmum of 6 wt.% Al2O3. The experimentally determined curves in this study were combined with the determined or estimated stability curves for hydrous melting, plagioclase, talc, anthophyllite, and antigorite to obtain a petrogenetic grid applicable to peridotites, modelled by the system H2O-CaO-MgO-Al2O3-SiO2, that covers a wide range of geological conditions. Direct applications of this grid, although quite limited, can be made for ultramafic assemblages that have been extensively re-equilibrated at greenschist to amphibolite facies metamorphism and for some highgrade ultramafic assemblages that display clear signs of retrogressive metamorphism.

Zur Stabilität von Margarit im System CaO-Al2O3-SiO2-H2O

An increasing number of occurrences of margarite have been reported in the last years. However, previous experimental investigations in the system CaO-Al2O3-SiO2-H2O are limited to the synthesis of margarite and to the upper stability limit according to the reaction (1) 1 margarite⇌1 anorthite +1 corundum +1 H2O (Chatterjee, 1971; Velde, 1971). Since margarite often occurs together with quartz, the upper stability limit of margarite in the presence of quartz is of special interest. Therefore, the reactions (5) 1 margarite +1 quartz ⇌1anorthite +1 kyanite/andalusite +1 H2O and (6) 4 margarite+3 quartz ⇌ 2 zoisite+5 kyanite+3 H2O were investigated experimentally using mixtures of natural margarite (from Chester, Mass., USA), quartz, kyanite, andalusite, zoisite, and synthetic anorthite. The indicated equilibrium temperatures at water pressures equal to total pressure are: 515± 25°C at 4 kb, 545 ±15°C at 5 kb, 590±10°C at 7 kb, and 650±10°C at 9 kb for reaction (5), and 651±11°C at 10 kb, 648 ± 8°C at 12.5kb, and 643±13°C at 15kb for reaction (6), respectively. Besides this, additional brackets for equilibrium temperatures were determined for the above cited reaction (1): 520±10°C at 3 kb, 580±10°C at 5 kb, and 640± 20°C at 7 kb. On the basis of these experimentally determined reactions (1), (5), and (6) and of the reactions (3) 2 zoisite +1 kyanite⇌ 4 anorthite +1 corundum +1 H2O (7) 2 zoisite +1 kyanite +1 quartz ⇌ 4 anorthite +1 H2O and (10) 1 pyrophyllite ⇌ 1 andalusite/kyanite+3 quartz+1 H2O for which experimental or, in the case of reaction (3), calculated data were already available, a pressure-temperature diagram with 3 invariant points and 11 univariant reactions was developed using the method of Schreinemakers. This diagram, summarizing both experimental and phase relation studies, allows conclusions about the conditions under which margarite has been formed in nature. Margarite is limited to low grade metamorphism at water pressures up to approximately 3.5 kb; in the presence of quartz, margarite is even limited to low grade metamorphism at water pressures up to 5.5 kb. Only at water pressures higher than the values stated before margarite, and margarite+quartz, respectively, can occur in medium grade metamorphism (as defined by Winkler, 1970 and 1973). For the combined occurrence of margarite+quartz and staurolite as reported by Harder (1956) and Frey (personal communication, 1973) it may be estimated that water pressure has been greater than approximately 5.5 kb, wheras temperature has been in the range from 550 to 650°C. Furthermore, the present study shows that the assemblage zoisite+kyanite (+ H2O) is an indicator of both pressure [P H 2 O> approximately 9kb]and temperature [T> approximately 640 to 650° Cat water Pressures up to 15 kb].

A model for phase equilibria in the prehnite-pumpellyite facies

Using the method of Schreinemakers, along with other thermodynamic considerations, a phase diagram for the system CaO-MgO-Al2O3-SiO2-CO2-H2O was constructed. The phases prehnite, pumpellyite, calcite, chlorite, dolomite, quartz, tremolite, talc, zoisite, grossularite and vapor were considered in this construction. The results indicate that prehnite-pumpellyite facies mineral assemblages will only exist in equilibrium with a vapor phase in which the mole fraction of CO2 is less than 0.2 at 1 kb, and less than 0.15 at 2 kb. Although talc could theoretically be a stable phase under these conditions, its common absence from rocks of this facies probably results from the existence of an enantiomorphic point which makes tremolite-calcite-CO2 the stable assemblage at low XCO2, and the compositionally equivalent talc-calcite-CO2 assemblage stable at moderate XCO2.

Prehnite- and Pumpellyite-Bearing Mineral Assemblages, West Side of the Appalachian Metamorphic Belt, Pennsylvania to Newfoundland

Prehnite- and/or pumpellyite-bearing meta-igneous rocks are found on the west side of the Appalachian metamorphic belt (1) near Jonestown, south-eastern Pennsylvania; (2) on Rensselaer Plateau, eastern New York; (3) near Quebec City, Quebec; and (4) at Little Port, Humber Arm, western Newfoundland. The assemblages critical to determining the conditions of metamorphism are (1) chlorite-epidote-hematite-pumpellyite-prehnite; actinolite-chlorite-hematite-pumpellyite-stilpnomelane; (2) actinolite-chlorite-epidote-stilpnomelane; chlorite-epidote-pumpellyite-stilpnomelane; chlorite-epidote-hematite-pumpellyite; (3) chlorite-epidote-hematite-pumpellyite-stilpnomelane; chlorite-epidote-pumpellyite-prehnite; and (4) chlorite-epidote-prehnite; chlorite-prehnite-stilpnomelane; chlorite-epidote-pumpellyite-prehnite. One pumpellyite-bearing rock from western Newfoundland shows a later vein of analcime-calcite. All the assemblages also include quartz, sphene, calcite, K-mica, and albite. Analysis of the mineral assemblages by the Schreinemakers method for the phases actinolite-chlorite-epidote-hematite-prehnite-pumpellyite-stilpnomelane shows that the different localities can be assigned different metamorphic grades. Though the detailed results of the Schreinemakers analysis depend on the assumed source of ferric iron in epidote, the major conclusions are not affected. The thermodynamic role of calcite is more problematic, but it appears that CO2 did not behave as a boundary-value component during metamorphism. If calcite is treated as an excess phase, the Schreinemakers bundle decomposes to a net in a multisystem. Plotted on such a net, the various localities again occupy different parts signifying different metamorphic grades. The occurrence of pumpellyite-bearing assemblages on the west flank of the northern Appalachian metamorphic belt might suggest that these assemblages, contrary to the ideas of Miyashiro and of others, do not indicate high-pressure and low-temperature type of metamorphism. These assemblages, however, are compatible with an alternative interpretation as remnants of a high-pressure, low-temperature Taconic metamorphic regime, whose imprint within most of the Appalachian metamorphic belt has been obliterated by later events. Such a reconstruction is compatible with the suggestion that this zone, lying near the margin of the early Paleozoic craton, was an active subduction zone during the Taconic orogeny.

Relationship between fluid-bearing and fluid-absent invariant points and a petrogenetic grid for a greenschist facies assemblage in the system CaO-MgO-Al2O3-SiO2-CO2-H2O

In the 6 component system CaO-MgO-Al2O3-SiO2-CO2-H2 with 9 solid phases (quartz, plagioclase, epidote, tremolite, talc, chlorite, magnesite, calcite, dolomite) and a fluid phase, all 17 possible fluid-absent reactions have been set up and balanced. Using molar entropy and volume data for the solid phases, these reactions are arranged in P-T space about the 8 possible fluid-absent invariant points after the method of Schreinemakers. Field observations in Ordovician greenschist facies basic volcanics at Sofala N.S.W., indicate that neither talc+epidote nor magnesite+calcite are stable under the conditions of metamorphism. Assuming these conditions to apply to the theoretical study here, the fluid-absent invariant points are arranged in a relative fashion with fluid-absent reactions subdividing P-T space into smaller areas.

Concentrations of CaAl2SiO6 component of diopsidic clinopyroxene in relation to mineral assemblages:An application of the method of SCHREINEMAKERS and ZEN

Concentrations of CaAl2SiO6 component of diopsidic clinopyroxene in relation to mineral assemblages:An application of the method of SCHREINEMAKERS and ZEN

A study of hydrated mercury and cadmium fluorides

Solubility relationships in the HgOHFH 2O system have been investigated at 25 °C in the 5–75% HF concentration range. The composition of the solid phases formed was established by the use of Schreinemaker's method. Two compounds were isolated: HgF 2·2H 2O, and its hydrolysis product, HgOHF. In the CdOHFH 2O system, CdF 2·2H 2O was isolated up to 10% HF concentration only. The compounds obtained were investigated by several physico-chemical methods. TGA showed a low, thermal stability for HgF 2·2H 2O and CdF 2·2H 2O. Infrared spectra indicated the presence of strong H-bonds in these hydrates. By the use of X-ray powder techniques, the two hydrates were shown to be isotypical and, presumably, isostructural. They are orthorhombic, with space groups Pnmm or Pnm21, and eight formulae units per unit cell, with cell parameters: a = 9.931 ± 0.003, b = 7.078 ± 0.002, c = 8.767 ± 0.003 A ̊ for CdF 2·2H 2O and a = 10.002 ± 0.002, b = 7.151 ± 0.001, c = 8.891 ± 0.001 A ̊ for HgF 2·2H 2O.

Discussion

Dr A. T. V. R othstein said that the resemblances, in features associated with magmatic currents and subsequent recrystallization, between the layered ultrabasic and basic bodies to the layered peridotite at Dawros in Connemara were considerable. One might wonder if the total range in the many ultrabasic bodies described by the authors encompassed that found in the single differentiated mass at Dawros? The point had been made that one group of the metaperidotites and metagabbroic rocks in the Lewisian had undergone granulite-facies metamorphism. To judge from several of the authors’ photomicrographs of these rocks, primary igneous textures might still be present in part in some of the ultrabasic varieties. This prompted a further inquiry concerning the possibility that some of these rocks had crystallized as igneous bodies under the conditions of a high metamorphic grade. This point was of particular relevance to the intrusions concerned. A comparison of the peridotites at Dawros in Connemara and at Belhelvie in Aberdeenshire by the speaker (Rothstein 1962, Magmatic facies in ultrabasic igneous rocks of the tholeiitic series. [In Russian with English summary] Publishing House of the U.S.S.R. Academy of Sciences) had shown that using the method of Schreinemakers it was possible to construct a P/T diagram for a simple ultrabasic system which had considerable points of similarity with natural occurrences and with synthetic systems investigated at various temperatures and pressures. Its main feature was the systematic relation of two metamorphic facies in wholly crystalline rocks to a sequence of magmatic facies, in certain of

Equilibria in the Sodium Phthalate-Sodium Bromide-Water System.

Materials and Methods. The sodium phthalate used in this investigation was prepared by neutralizing pure phthalic anhydride with pure sodium carbonate and recrystallizing the product from aqueous solution. The composition of the hydrate has been shown by Foote and Smith (I) to be 2NazC*H4O4. 7H20. Hydrated sodium bromide was prepared by recrystallizing reagent grade sodium bromide in water below 51 C. Anhydrous sodium bromide was prepared by drying the recrystallized product a t 110 C. Solubilities were determined by analyzing solutions obtained by rotating mixtures of the three components in an electrically controlled thermostat until equilibrium was established. A minimum of 24 hours was allowed for the attainment of equilibrium. In some instances, a t C. and again where solid solution exists, three to four days were required. In preparing the original complexes, wherever possible the salts were used which exist as solid phases when equilibrium is reached. Temperature variations were within ~ 0 . 0 5 C. Samples for analysis were obtained by allowing the equilibrium mixtures to settle and drawing off portions of the supernatant liquid by means of a pipet carrying a small cotton filter. Samples were weighed in a calibrated volumetric flask and aliquot portions used for analysis. Sodium bromide was determined by precipitation as silver bromide with an excess of standard silver nitrate in acid solution and the excess titrated with standard thiocyanate solution. Total sodium was determined by acidifying a second aliquot portion with sulfuric acid and evaporating to dryness. Excess sulfuric acid was removed by ignition in a current of ammonia. From the weight of the resultant sodium sulfate and the sodium bromide previously determined, the percentage of sodium phthalate was calculated. The wet residues were quickly dried between sheets of filter paper and analyzed by the same procedures. Their composition was determined by the graphic method of Schreinemakers ( 2 ) . Experimental Results. Isotherms a t 0, 25, 35, 45, and 50 C. have been completed. At O, 25, so, and 45 only two solid phases existed. The isotherms therefore consist of two isothermally univariant curves intersecting a t an isothermally invariant point. At 50 C. two more solid phases appeared, so that this isotherm 'consists of four isothermally univariant curves and three isothermally invariant points. Experimental results are given in Table I. P is used here as in previous work to designate the phthalate radical, C s H I 0 4 . Solid phases are represented as:

Hydrogen peroxide and its analogues. II. Phase equilibrium in the system hydrogen peroxide-water.

A precision freezing point apparatus with platinum resistance thermometer was used to investigate the system hydrogen peroxide – water over the whole concentration range. The freezing point of the purest sample of hydrogen peroxide obtained by repeated fractional crystallizations of a large quantity of 99.6% pure solution was found to be −0.461°C; that of the dihydrate was −52.10°C. The two eutectics occur at concentrations of 45.2% and 61.2% H2O2 and at temperatures of −52.4° and −56.5°C. respectively. Contrary to what has been reported previously, water and hydrogen peroxide do not form solid solutions together. This was proved conclusively by applying the technique of radioactive tracers to the 'wet residue' method of Schreinemakers.