497-19-8Relevant articles and documents
Deshpande, D. A.,Ghormare, K. R.,Jawadekar, V. L.,Deshpande, N. D.
, p. 295 - 302 (1983)
Thermal decomposition of NaHCO3 powders and single crystals. A study by DSC and optical microscopy
Guarini, G. G. T.,Dei, L.,Sarti, G.
, p. 31 - 44 (1995)
The thermal decomposition of four commercial powders and of differently stored single crystals of sodium hydrogen carbonate is studied by power compensation DSC and by optical and FT-IR microscopy. Independently of manufacturer, specified purity and price, the thermal curves of all the commercial powders show a more or less pronounced low temperature peak preceding the one due to the main decomposition. Such small peak is not observed when samples of laboratory recrystallized material are used. However the thermal behaviour of the latter preparation differs remarkably depending on storage conditions: the material kept in closed glass containers decomposes at temperatures higher than those of the material stored in a desiccator in the presence of concentrated H2SO4. The observation by optical microscopy of the behaviour of the surfaces of single crystals coming from different storage conditions when the temperature is raised in a Kofler heater helps the interpretation of the data collected. The mechanism of the decomposition is discussed and the relevant kinetic parameters reported.
Waldbauer, L.,McCann, D. C.,Tuleen, L. F.
, p. 336 - 337 (1934)
Interaction of graphite with hydroxide-salt melts
Zarubitskii,Dmitruk,Zakharchenko
, p. 525 - 528 (2006)
The mechanism and kinetics of graphite dissolution in melts based on sodium hydroxide were studied. The effect of various salt additives on the intensity of the occurring reactions is considered. A method recommended for removal of graphite in the form of remainders of molds and mold cores from titanium casts is described. Pleiades Publishing, Inc., 2006.
Smith, G. F.,Croad, F.
, p. 141 - 142 (1937)
Kinetic studies on the thermal decomposition of aluminium doped sodium oxalate under isothermal conditions
Jose John,Muraleedharan,Kannan,Abdul Mujeeb,Ganga Devi
, p. 64 - 70 (2012)
The kinetics of thermal decomposition of sodium oxalate (Na 2C2O4) has been studied as a function of concentration of dopant, aluminium, at five different temperatures in the range 783-803 K under isothermal conditions by thermogravimetry (TG). The TG data were subjected to both model fitting and model free kinetic methods of analysis. The model fitting analysis of the TG data shows that no single kinetic model describes the whole α versus t curve with a single rate constant throughout the decomposition reaction. Separate kinetic analysis shows that Prout-Tompkins model best describes the acceleratory stage of the decomposition while the decay region is best fitted with the contracting cylinder model. Activation energy values were evaluated by model fitting and model free kinetic methods for both stages of decomposition. As proposed earlier the results favours a diffusion controlled mechanism for the isothermal decomposition of sodium oxalate.
Quantitative kinetic and structural analysis of geopolymers. Part 1. the activation of metakaolin with sodium hydroxide
Zhang, Zuhua,Wang, Hao,Provis, John L.,Bullen, Frank,Reid, Andrew,Zhu, Yingcan
, p. 23 - 33 (2012)
Isothermal conduction calorimetry (ICC) is used here to measure the kinetics of geopolymerisation of metakaolin by reaction with NaOH solution under a variety of conditions. Three exothermic peaks are observed in the calorimetric curve, and are assigned to the dissolution of metakaolin, the formation of geopolymer with disordered or locally ordered structure, and finally the reorganization and partial crystallization of this inorganic polymer gels. For the purpose of further quantifying the ICC data, the geopolymeric reaction products are assumed to have an analcime-like local structure, and their standard formation enthalpies are estimated from the available data for this structure. This assumption enables ICC to be used for the first time in a quantitative manner to determine the real reaction kinetics of geopolymerization. Increasing the NaOH concentration up to a molar overall Na/Al ratio of 1.1 is seen to enhance the reaction extent observed at 3 days, up to a maximum of around 40% in the high liquid/solid ratio systems studied here, and accelerates the crystallization process. However, further addition of NaOH does not give any additional reaction within this period, or any further acceleration. Raising the reaction temperature from 25 °C to 40°C increases the initial reaction rate but has little effect on the final reaction extent, particularly when Na/Al > 1.
Thermal Decomposition of Solid Sodium Bicarbonate
Ball, Matthew C.,Snelling, Christine M.,Strachan, Alec N.,Strachan, Rebecca M.
, p. 3709 - 3716 (1986)
The thermal decomposition of solid sodium bicarbonate has been studied in the temperature range 360-500 K over a range of partial pressures of carbon dioxide.The effect of water vapour has also been studied.Above 440 K the reaction follows contracting-cube kinetics with an activation energy of 32 kJ mol-1 and a frequency factor of 101 s-1.In this temperature range the presence of water or carbon dioxide has little effect on the kinetics.Below 390 K the reaction follows first-order kinetics.In nitrogen, the activation energy is ca. 64 kJ mol-1, the frequency factor is 105 s-1 and water vapour has little effect.High partial pressures of carbon dioxide increase the activation energy to ca. 130 kJ mol-1 and the frequency factor to 1013.5 s-1.The results of microscopic examination generally confirm the kinetics but show that at low temperatures in nitrogen and carbon dioxide the process are different in detail.
Synthesis, spectroscopy, single crystal XRD and biological studies of multinuclear organotin dicarboxylates
Hussain, Shabbir,Ali, Saqib,Shahzadi, Saira,Tahir, Muhammad Nawaz,Shahid, Muhammad,Munawar, Khurram Shahzad,Abbas, Syed Mustansar
, p. 64 - 72 (2016)
Multinuclear organotin(IV) dicarboxylates of the general formula (Me3Sn)2L·H2O (1), (Ph3Sn)2L (2) and Me2SnL[Sn(Cl)2Me2]2 (3) were synthesized by refluxing disodium iminodiacetate hydrate (Na2L·H2O) with Me3SnCl/Ph3SnCl/Me2SnCl2 in methanol. The elemental analysis (C, H and N) data agreed well with the chemical compositions of the products. IR spectroscopy demonstrated a bridging coordination mode of the carboxylate group. 1H NMR spectroscopy suggested a penta-coordinated environment around the tin(IV) center in complexes 1 and 3. The title complex 3 represents one of the very few examples of organotin(IV) carboxylates showing simultaneously coordination with dimethyltin(IV) as well as dichlorodimethyltin(IV) moieties, by substitution and addition reactions, respectively. The 13C NMR spectroscopy demonstrated the carboxylate-metal linkages. EIMS and ESI spectra verified the molecular skeletons of the products 1-3. Thermogravimetric analysis revealed the bimetallic nature of 2. A single crystal XRD study of 3 has shown a predominantly square pyramidal geometry with some trigonal bipyramidal characteristics around each metal center. The novel products exhibited antibacterial/antifungal potential and their minimal inhibitory concentrations (MIC) were also evaluated. In vitro hemolytic studies on human red blood cells indicated a slightly toxic nature of the synthesized complexes.
Fry, H. S.,Schulze, E. L.
, p. 1131 - 1138 (1928)
Easterbrook, W. C.
, p. 383 - 390 (1957)
Tanaka, H.
, p. 521 - 526 (1987)
PbTe nanostructures: Microwave-assisted synthesis by using lead Schiff-base precursor, characterization and formation mechanism
Ahmadian-Fard-Fini, Shahla,Salavati-Niasari, Masoud,Monfared, Azam,Mohandes, Fatemeh
, p. 778 - 788 (2013)
Pure cubic phase lead telluride (PbTe) nanostructures have been produced by using a Schiff-base complex as a precursor in the presence of microwave irradiation. The Schiff base used as ligand was derived from salicylaldehyde and ethylenediamine. The Schiff-base complex was marked as [Pb(salen)]. In addition, the effect of the irradiation time and the type of reducing agent on the morphology and purity of the final products was investigated. The as-synthesized PbTe nanostructures were characterized extensively by techniques like X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM). The microwave formation mechanism of the PbTe nanostructures was studied by XRD patterns of the products. Although it was found that both ionic and atomic mechanisms could take place for the preparation of PbTe, the main steps were according to the atomic reaction process, which could occur between elemental Pb and Te.
Gorski, A.,Krasnicka, A. D.
, p. 1895 - 1904 (1987)
Worm
, p. 688 - 688 (1897)
Duval, C.,Wadier, C.,Servigne, Y.
, p. 263 - 267 (1959)
Thermal decomposition of copper(II) and zinc carbonate hydroxides by means of TG-MS: Quantitative analyses of evolved gases
Koga,Tanaka
, p. 725 - 729 (2005)
For the quantitative analyses of evolved CO2and H2O during the thermal decomposition of solids, calibration curves, i.e. the amounts of evolved gases vs. the corresponding peak areas of mass chromatograms measured by TG-MS, were plot
The hidden equilibrium in aqueous sodium carbonate solutions - Evidence for the formation of the dicarbonate anion
Zeller, Klaus-Peter,Schuler, Paul,Haiss, Peter
, p. 168 - 172 (2005)
Crossover 13C NMR experiments between [13C]carbonate and [18O]carbonate in aqueous solution confirm the combined action of two oxygen-exchange modes. The isotopomeric carbon dioxides formed in the hydrolysis equilibrium of
Marotta, A.,Saiello, S.,Buri, A.
, p. 193 - 198 (1982)
Thermal Decomposition of Solid Sodium Sesquicarbonate, Na2CO3*NaHCO3*2H2O
Ball, Matthew C.,Snelling, Christine M.,Strachan, Alec N.,Strachan, Rebecca M.
, p. 631 - 636 (1992)
The thermal decomposition of solid sodium sesquicarbonate has been studied at temperatures between 350 and 487 K in nitrogen and carbon dioxide atmospheres.In nitrogen, a single-stage decomposition to sodium carbonate occurs, following Avrami-Erofeyev kinetics (n = 2), with an inflexion at ca. 390 K.The activation energies are 24 kJ mol-1 for the high-temperature region and 58 kJ mol-1 for the low-temperature region.In carbon dioxide above 435 K, the single-stage reaction follows contracting disc kinetics with an activation energy of 29 kJ mol-1.In carbon dioxide at low temperatures, wegscheiderite (Na2CO3*3NaHCO3) and sodium carbonate monohydrate (Na2CO3*H2O) are formed, and this reaction follows first-order kinetics, withb an activation energy of 67 kJ mol-1.Microscopic evidence is also presented.Relationships between the decomposition of sesquicarbonate and other related compounds are discussed.
Galwey, Andrew Knox,Hood, William John
, p. 1810 - 1816 (1979)
Fire retardancy impact of sodium bicarbonate on ligno-cellulosic materials
Bakirtzis,Delichatsios,Liodakis,Ahmed
, p. 11 - 19 (2009)
In this paper, the effect of NaHCO3 as fire retardant additive during pyrolysis and combustion has been investigated. Four different contents (5%, 10%, 15%, and 20% w/w) of NaHCO3 have been tested on Pinus brutia, Laurus nobilis and
Features of the Thermolysis of Li, Na, and Cd Maleates
Avdin, V. V.,Merzlov, S. V.,Nayfert, S. A.,Polozov, M. A.,Polozova, V. V.,Sakthi Dharan, C. P.,Taskaev, S. V.,Zherebtsov, D. A.
, p. 1311 - 1318 (2020/07/21)
Abstract: Processes of the multi-stage decomposition of maleic acid and Li, Na, and Cd maleates in an inert atmosphere are studied via thermal analysis with synchronous analysis of the composition of the released gases. Reaction mechanisms are proposed according to the data on the mass loss stages determined via thermal analysis, gaseous products, and the final solid decomposition products. It is shown that when heated to 700°C, Li and Na carbonates incorporated into the porous carbon matrix are the final products. Above 350°C, cadmium is reduced from oxide to metal and evaporates to form a porous carbon residue as the only product of thermolysis. All carbon products are X-ray amorphous. Maleic acid decomposes completely into gaseous products in the range of 133–239°C. The maleate ion is more stable in the structure of lithium maleate than in free maleic acid, and Na and Cd cations reduce its stability.
METHOD FOR PRODUCING METAL CARBONATE AND CATALYST FOR PRODUCING THE SAME
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Paragraph 0023; 0024, (2017/08/26)
A method for producing metal carbonate is disclosed. The method includes the following steps of providing a first mixture of metal and a catalyst containing iron, NO groups, and N-containing ligands first; then introducing carbon dioxide to the first mixture to form a second mixture and obtaining a product. The method described here can improve the yield and decrease the cost of metal carbonate production.
