Pub Date : 1989-04-01DOI: 10.1016/0168-7336(89)80009-9
O. García, P. Millán, R.M. Rojas ∗, E. Vila
Thermal decomposition of several copper(II)-cobalt(II) hydroxide chlorides, β-CuxCo2−x(OH)3Cl (0.34 ⩽ x ⩽ 1.5) has been carried out in an evacuated high temperature X-ray diffraction chamber. The cubic spinel phase CuyCo3−yO4 and the cubic rock-salt phase (Cu,Co)Oss are two of the intermediates that form during the decompositions, while cobalt metal or a mixture of cobalt and copper metals are obtained as final products, their relative amounts depending on the value of the stoichiometric coefficient x of the precursors.
{"title":"Study of the thermal decomposition of the copper substituted cobalt hydroxide chloride series, β-CuxCo2−x(OH)3Cl, by high tempe","authors":"O. García, P. Millán, R.M. Rojas ∗, E. Vila","doi":"10.1016/0168-7336(89)80009-9","DOIUrl":"10.1016/0168-7336(89)80009-9","url":null,"abstract":"<div><p>Thermal decomposition of several copper(II)-cobalt(II) hydroxide chlorides, β-Cu<sub><em>x</em></sub>Co<sub>2−<em>x</em></sub>(OH)<sub>3</sub>Cl (0.34 ⩽ <em>x</em> ⩽ 1.5) has been carried out in an evacuated high temperature X-ray diffraction chamber. The cubic spinel phase Cu<sub><em>y</em></sub>Co<sub>3−<em>y</em></sub>O<sub>4</sub> and the cubic rock-salt phase (Cu,Co)O<sub>ss</sub> are two of the intermediates that form during the decompositions, while cobalt metal or a mixture of cobalt and copper metals are obtained as final products, their relative amounts depending on the value of the stoichiometric coefficient <em>x</em> of the precursors.</p></div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"7 1","pages":"Pages 75-81"},"PeriodicalIF":0.0,"publicationDate":"1989-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(89)80009-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86018082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-02-01DOI: 10.1016/0168-7336(89)80072-5
G. Mink, I.S. Pap, I. Bertóti, T. Székely, E. Karmazsin
The role of surface alkali and phosphorus additives on the time-dependence of the reaction of TiO2 with COCl2 has been studied by a reactive thermogravimetric method. At conversions below 0.7 apparent fractional orders with respect to the solid were found to be 1 (for TiO2-Li(s) and TiO2-Na(s)) and 2 (for TiO2-K(s)); these formal orders, however, provided insufficient information for describing the conversion vs. time curves above α = 0.7. The proposed kinetic model which enables satisfactory curve fitting even for high conversions involves a non-uniform particle size distribution, together with the surface enrichment of phosphorus as retardant during the shrinking of the particles, which results in a steady decrease in the linear reaction rate.
{"title":"Chlorination of titanias modified by alkali and/or phosphorus additives","authors":"G. Mink, I.S. Pap, I. Bertóti, T. Székely, E. Karmazsin","doi":"10.1016/0168-7336(89)80072-5","DOIUrl":"10.1016/0168-7336(89)80072-5","url":null,"abstract":"<div><p>The role of surface alkali and phosphorus additives on the time-dependence of the reaction of TiO<sub>2</sub> with COCl<sub>2</sub> has been studied by a reactive thermogravimetric method. At conversions below 0.7 apparent fractional orders with respect to the solid were found to be 1 (for TiO<sub>2</sub>-Li(s) and TiO<sub>2</sub>-Na(s)) and 2 (for TiO<sub>2</sub>-K(s)); these formal orders, however, provided insufficient information for describing the conversion vs. time curves above α = 0.7. The proposed kinetic model which enables satisfactory curve fitting even for high conversions involves a non-uniform particle size distribution, together with the surface enrichment of phosphorus as retardant during the shrinking of the particles, which results in a steady decrease in the linear reaction rate.</p></div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"6 4","pages":"Pages 335-348"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(89)80072-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74595051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-02-01DOI: 10.1016/0168-7336(89)80074-9
El-Zeiny M. Ebeid, Ahmed M. Donia, Fathy A. El-Saied
The crystalline salicylidene-4-amino-antipyrene derivative (I) is photolabile and undergoes photochromism and an associated structural change. The compound shows a reasonable solid-state thermal stability but undergoes thermal decomposition in the fused phase.
{"title":"Photochromy and thermal stability of crystalline salicylidene-4-amino-antipyrene","authors":"El-Zeiny M. Ebeid, Ahmed M. Donia, Fathy A. El-Saied","doi":"10.1016/0168-7336(89)80074-9","DOIUrl":"10.1016/0168-7336(89)80074-9","url":null,"abstract":"<div><p>The crystalline salicylidene-4-amino-antipyrene derivative (I) is photolabile and undergoes photochromism and an associated structural change. The compound shows a reasonable solid-state thermal stability but undergoes thermal decomposition in the fused phase.</p></div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"6 4","pages":"Pages 361-368"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(89)80074-9","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90575930","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-02-01DOI: 10.1016/0168-7336(89)80075-0
C.E. Bamberger ∗ , C.S. MacDougall , O.B. Cavin
{"title":"Formation of molybdenum carbides by reaction of molybdenum compounds with molten sodium cyanide","authors":"C.E. Bamberger ∗ , C.S. MacDougall , O.B. Cavin","doi":"10.1016/0168-7336(89)80075-0","DOIUrl":"10.1016/0168-7336(89)80075-0","url":null,"abstract":"","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"6 4","pages":"Pages 369-372"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(89)80075-0","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73501442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-02-01DOI: 10.1016/0168-7336(89)80087-7
{"title":"Calendar of forthcoming events","authors":"","doi":"10.1016/0168-7336(89)80087-7","DOIUrl":"https://doi.org/10.1016/0168-7336(89)80087-7","url":null,"abstract":"","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"6 4","pages":"Pages 386-388"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(89)80087-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136578019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-02-01DOI: 10.1016/0168-7336(89)80073-7
L. Burzyńska, Z. Zembura ∗, J. Karp
The solid products of the dissolution of β'-ordered brass in deaerated 2.0 M H2SO4 have been studied by optical and electron microscopy and X-ray diffraction. It has been found that the thickness of the zinc-leached layer as time function satisfies the Erofeev equation, a layer of variable zinc contents exists in the interphase zone: brass-pure copper and a brass of bainite structure appears at the surface of the β'-ordered brass. On the assumption that the reduction of H+ ions is the rate-determining step of the electrochemical process the hypothesis that the rate of dissolution of brass controls the formation and growth of metallic copper phase has been corroborated.
用光学显微镜、电子显微镜和x射线衍射研究了β′有序黄铜在去氧2.0 M H2SO4中溶解的固体产物。结果表明:锌浸出层厚度随时间的变化满足Erofeev方程，相间区存在一层锌含量变化的层，β′有序黄铜表面出现一层贝氏体结构的黄铜。在假设氢离子还原是电化学过程的速率决定步骤的基础上，证实了黄铜溶解速率控制金属铜相形成和生长的假设。
{"title":"Kinetics of the spontaneous dissolution of copper-47.3 atom-% zinc brass with hydrogen depolarization","authors":"L. Burzyńska, Z. Zembura ∗, J. Karp","doi":"10.1016/0168-7336(89)80073-7","DOIUrl":"10.1016/0168-7336(89)80073-7","url":null,"abstract":"<div><p>The solid products of the dissolution of β'-ordered brass in deaerated 2.0 <em>M</em> H<sub>2</sub>SO<sub>4</sub> have been studied by optical and electron microscopy and X-ray diffraction. It has been found that the thickness of the zinc-leached layer as time function satisfies the Erofeev equation, a layer of variable zinc contents exists in the interphase zone: brass-pure copper and a brass of bainite structure appears at the surface of the β'-ordered brass. On the assumption that the reduction of H<sup>+</sup> ions is the rate-determining step of the electrochemical process the hypothesis that the rate of dissolution of brass controls the formation and growth of metallic copper phase has been corroborated.</p></div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"6 4","pages":"Pages 349-359"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(89)80073-7","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75304707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 1989-02-01DOI: 10.1016/0168-7336(89)80071-3
G. Mink ∗, I.S. Pap, I. Bertóti, T. Székely, E. Karmazsin, A. Dassler
The kinetics of the chlorination of titania modified by alkali and/or phosphorous additives, were studied by thermogravimetric methods using COCl2 and gaseous CCl4 as chlorinating agents. The chlorination of pure titania was compared with that of phosphorous-containing compounds, TiO2 · nP2O5 and K3P3O9 were also investigated. Apparent activation energies and reaction orders were calculated from the dependence of the initial rates on temperature and partial pressure.
With COCl2 as chlorinating agent and increased alkali content of the samples resulted in an increase in the reaction rate, whereas the phosphorous additive behaved as a retardant, and their inhibiting effects became more and more pronounced in the course of the reaction. On the other hand when chlorinating with CCl4, high amounts of K or Na additives retarded the reaction, and Li enhanced the chlorination.
{"title":"Chlorination of titanias modified by alkali and/or phosphorus additives","authors":"G. Mink ∗, I.S. Pap, I. Bertóti, T. Székely, E. Karmazsin, A. Dassler","doi":"10.1016/0168-7336(89)80071-3","DOIUrl":"10.1016/0168-7336(89)80071-3","url":null,"abstract":"<div><p>The kinetics of the chlorination of titania modified by alkali and/or phosphorous additives, were studied by thermogravimetric methods using COCl<sub>2</sub> and gaseous CCl<sub>4</sub> as chlorinating agents. The chlorination of pure titania was compared with that of phosphorous-containing compounds, TiO<sub>2</sub> · <em>n</em>P<sub>2</sub>O<sub>5</sub> and K<sub>3</sub>P<sub>3</sub>O<sub>9</sub> were also investigated. Apparent activation energies and reaction orders were calculated from the dependence of the initial rates on temperature and partial pressure.</p><p>With COCl<sub>2</sub> as chlorinating agent and increased alkali content of the samples resulted in an increase in the reaction rate, whereas the phosphorous additive behaved as a retardant, and their inhibiting effects became more and more pronounced in the course of the reaction. On the other hand when chlorinating with CCl<sub>4</sub>, high amounts of K or Na additives retarded the reaction, and Li enhanced the chlorination.</p></div>","PeriodicalId":101061,"journal":{"name":"Reactivity of Solids","volume":"6 4","pages":"Pages 321-333"},"PeriodicalIF":0.0,"publicationDate":"1989-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0168-7336(89)80071-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80429015","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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