The Effect of TiO2 on the Optical and Mechanical Properties of Heavy Metal Oxide Borosilicate Glasses

Silicon - The density, the molar volume, the rigidity, the UV reflectance and the glass transition temperatures of the x TiO2 – 20Na2B4O7 – 30PbO – 20SiO2 – (30-x) Bi2O3...     

Research on the Effects of Yttrium on Bismuth Titanate Borosilicate Glass System

Silicon - Glasses with the chemical composition of 52B2O3 – 12SiO2–26Bi2O3 – (10 − x)TiO2 - xY2O3, :(0 ≤ x ≤ 10) prepared...     

Linear Optical Properties of x PbO – 20 SiO2–10 Na2O – (70 - x) B2O3 Glass System

Silicon - Optical spectral analysis of a glass system with composition xPbO – 20 SiO2–10 Na2O – (70 - x) B2O3, where x = 20, 30, 40, 50 and 60 mol %, was studied. The investigated...     

Synthesis and Properties of Mullite–Sialon–ZrB2Materials Produced Using a Spark-Plasma Technique

Refractories and Industrial Ceramics - The sialon-to-ZrB2 ratio during spark-plasma sintering at pressing load 75 MPa and 1200 – 1600°C influenced the phase composition, Si3N4 and Al2O3...     

Effect of Tungsten Oxide on the Crystallization Properties of Glasses of the B2O3–La2O3–Nb2O5 System

Glass Physics and Chemistry - The effect of tungsten oxide on the crystallization properties of glasses of the 37.5B2O3 22.5La2O3 (40 – x)Nb2O5 xWO3 (where x = 10, 15, 20, 30, 40 mol %)...     

Electronic Spectra of Er(III) Ions in Sodium-Borate Melts

Glass Physics and Chemistry - In this work, the results of the spectral studies of xNa2O · (100 – x)B2O3 · Er2O3 (x = 0–45) melts at 1273 K are presented. When increasing the...     

On the Electric and Dielectric Properties of Some Boro-Lead Sulphate Glasses

Glass Physics and Chemistry - Binary oxide glass system of the composition (100 – x)B2O3?xPbSO4 [0 ≤ x ≤ 40] is prepared by the press-quenching technique. The X-ray...     

Interdependence of sodium and potassium substitution in tricalcium aluminate

The maximum extent of K₂O substitution in cubic Ca₃A?₂O₆ is 0.75 – 1.0 wt. % at 1000 – 1200°C. Na is required to form orthorhombic solid solutions, but these exhibit appreciably higher solubilities for K₂O, ranging up to 2.0 – 2.5 wt. %, than the cubic solid solutions.     

Sintering a Mixture of Powders in the Al2O3–SiO2–β-SiAlON–TiC–Dy2O3 System by the Spark-Plasma Method with High Compaction Loading

Refractories and Industrial Ceramics - The effect of the addition of 2 and 5 mol.% Dy2O3 during spark-plasma sintering at a compaction loading of 60 MPa in the range of 1200 – 1600°C on...     

Thermostable Transparent Lithium-Aluminosilicate Sitall Doped with Neodymium Oxide

Glass and Ceramics - The effect of adding the oxide Nd2O3(0.1 – 3.0 mol.%) on the synthesis conditions, crystallization, and spectral properties of a thermostable...     

Phase Composition and Structure of Aluminum – Coating Composite

Low-melting enamel coatings for household aluminum kitchenware are synthesized. The possibility of formation of low-melting glasses in the system R₂O – Al₂O₃ – B₂O₃ – TiO₂ – P₂O₅ is studied. An optimum glass matrix composition with a decreased firing temperature (580°C) is selected.     

Preparation,IR, UV,NMR, and Mass Spectral Fragmentations of New Substituted Phenoxaphosphinic Acids

The synthesis and IR, UV, NMR; and mass spectral fragmentations of substituted phenoxaphosphinic acids I – XIV are reported. A diazo method gave I, and the Friedel-Crafts method II – XIV. Infrared assignments: POH, broad bands, 2600, 2250, and 1650; C-P, 1490 - 1440; C-O, 1280 - 1260; P=0, 1190 - 1140; and P-O, 978 - 974 cm^?1. Characteristic bands also occur at 1330 - 1320 and 1230 - 1210 cm^?1. The UV spectra possess maxima at 210 - 220 mμ (log ∈ 4.50 - 4.60), 240 - 250 (4.20 - 4.30), and 298 – 304 (3.65 – 3.75). The NMR spectra give τ 7.56 ppm for a 2-methyl substituent, 7.48 for a 4-methyl and a quartet at 7.26 and a triplet at 8.71 (J = 7.7 Hz) for a 2-ethyl. The chemical shifts were virtually unaffected by alkyl or halogen substituents on the other aromatic ring but were shifted upfield by ortho or meta methyl substituents on the same ring. Singlets at τ 7.44 and 7.60 ppm in the spectrum of VIII gave calculated base values of about 7.28 and 7.44 for a 1-methyl and 3-methyl, respectively. The mass spectra are greatly influenced by the substituents. All showed loss of PO₂H from the molecular ion or in the case of ethyl compounds after CH₃^· expulsion. CHO or CCIO was then eliminated. The molecular ions of methyl compounds eliminated H₂O.     

Preparation and crystallite growth measurement of active magnesium aluminate spinel

MgAl₂O₄ was prepared by cocrystallizing and decomposing Al(NO₃)₃.9H₂O and Mg(NO₃)₂.6H₂O mixture. The crystallite growth of the resulting powder was studied in the temperature range 500 – 1000 °C. It was found that the equation governing the process is D² – D²₀ = KT. Two activation energies for crystallite growth were obtained, 22 kcal and 44 kcal for the temperature ranges 500 – 785 °C and 785 – 1000 °C respectively. It was noted that rapid increase in crystallite size occurred on soaking at a temperature > 800 °C.     

Folgeprodukte halogenierter Aldehyde. X. Die Synthese von O-Polyhalogenalkyl-dichlorphosphaten und O,O-Dialkyl-O-polyhalogenalkyl-phosphaten

Derivatives of Halogenated Aldehydes. X. The Synthesis of O-Polyhalogenoalkyl Phosphorodichloridates and O,O-Dialkyl-O-polyhalogenoalkyl Phosphates The phosphorodichloridates 2a – e are prepared by reaction of halogenated aldehydes or of glyoxylic acid n-butyl ester with phosphorus pentachloride or PCl₃Br₄ and subsequent treatment with sulfur dioxide. The compounds 2a – e give the phosphates 3a – i by reaction with alcohols.     

Improved ethynylation of nitrocarbonyl derivatives by cerium trichloride assisted addition of ethynyl magnesium bromide

The addition of the Grignard reagent ethynyl magnesium bromide to nitroarylcarbonyls in the presence of cerium chloride was investigated. Thus, 2- and 4-nitrobenz-aldehyde, 2- and 4-nitroacetophenone, 2-nitrocinnamaldehyde and 1-aryl-3-aryl"-2-en-propanones (nitrochalcones 4a – g ), gave α-ethynyl-2- and 4-nitrophenylmethanol 2a – b , α-ethynyl-2- and 4-nitrophenyl ethanol 2c – d , trans-1-(2-nitrophenyl)-1-penten-4-yn-3-ol ( 5 ) and trans-1-aryl-3-aryl"-1-penten-4-yn-3-ol 6a – g , respectively. It was found that in the absence of the lanthanide, the ethynylation reaction was a low yielding process.     

Reactions with 2-thiazolin-5-ones. III. The behaviour of 4-Arylazo-2-alkoxy-2-thiazolin-5-ones toward amines and Grignard reagents

Treatment of 4-arylazo-2-alkoxy-2-thiazolin-5-ones 4a – f with glycine or phenylhydrazine effects their conversion into 1-aryl-5-alkoxy-1 H-1,2,4-triazole-3-carboxylic acid derivatives 5a – j , with the loss of hydrogen sulfide. On the other hand, the reaction of the 2-ethoxy ( 4a – c ) and the 2-isopropyloxy ( 4g – i ) derivatives with strong basic amines involves the loss of an alkyl mercaptan to yield the N-substituted amines 7d – j of 1-aryl-Δ²-1,2,4-triazolin-5-one-3-carboxylic acids. The 2-benzyloxy derivatives 4d – f react with the same reagents to give the N-substituted amides 2a – g of 1-aryl-Δ²-1,2,4-triazolin-5-thione-3-carboxylic acids, with the loss of benzyl alcohol. Hetero-ring opening of 4 , followed by recyclisation, occurs upon treatment with ethyl or phenyl magnesium halides to yield the triazolinethione derivatives 13 a – c .     

磁性固体超强酸的制备及催化合成乙酸异戊酯的研究

采用共沉淀法制备SO42-/Fe3O4-Al2O3-ZrO2-Nd2O3磁性固体超强酸催化剂,应用于乙酸异戊酯的合成。利用XRD、IR、EDS、SEM等测试手段对催化剂结构进行了表征,结果表明,SO42-/Fe3O4-Al2O3-ZrO2-Nd2O3磁性固体超强酸中ZrO2以四方晶相(T相)稳定存在,SO42-与金属离子以桥式双配位结合;催化剂表面疏松多孔,具有很大的比表面积。将磁性固体超强酸催化剂应用于合成乙酸异戊酯的反应中,采用均匀设计实验,利用U11(1110)表,考察了各种因素对酯化率的影响,确定最佳合成工艺条件为:催化剂加入1.58 g,n(乙酸)∶n(异戊醇)=1∶1.8,反应时间为3.16 h,酯化率达98%以上。乙酸异戊酯产品结构经折光率、红外光谱进行了表征与确认。同时实验表明,SO42-/Fe3O4-Al2O3-ZrO2-Nd2O3磁性固体超强酸催化剂可多次重复使用,活化降低不大,是一种稳定性高、选择性好的新型环境友好的催化剂。     

固体酸催化乙酸丁醇酯化反应的研究

制备了SO42 - /Fe2 O3 ZrO2 SiO2 、SO42 - /Fe2 O3 SiO2 、SO42 - /ZrO2 SiO2 、SO42 - /TiO2 SiO2 等固体酸 ,用于催化乙酸 丁醇液相酯化反应 ,发现SO42 - /Fe2 O3 ZrO2 SiO2 固体酸具有良好的催化性能 ,其乙酸丁酯收率和酯化选择性可分别达到 93.2 6%和 96.0 0 % ,对SO42 - /Fe2 O3 ZrO2 SiO2 进行了XRD、BET和TGA表征 ,发现该类催化剂的成分主要以无定形状态存在 ,SO42 - 可能是该类催化剂的活性组分之一 ,催化剂失活的主要原因在于反应中SO4 2 - 的流失。     

Tinted Low-Melting Enamels for Aluminum

The possibility of formation of low-melting glasses in the R₂O – RO – Al₂O₃ – B₂O₃ – TiO₂ – P₂O₅ system at a firing temperature of 550°C is investigated. A correlation of glass formation in the considered system with the content of Al₂O₃ and P₂O₅ is established, and the composition of a transition layer with crystalline phases of Na₂O · P₂O₅, Al₂O₃ and Al₂O₃ · P₂O₅ is determined.     

Synthesis and characterization of new bis(crown ether)s of Schiff base type containing recognition sites for sodium and nickel guest cations

New bis(crown ether) ligands of Schiff base type ( 2 – 4 ) containing recognition sites for sodium and nickel guest cations have been synthesized by the condensation of two equivalents of 4′-formyl-5′-hydroxy(benzo-15-crown-5) ( 1 ) with diamines, H₂N–(CH₂)_n–NH₂(n = 2–4). Homonuclear ditopic crystalline 2 : 1 (Na⁺ : ligand) complexes ( 2a – 4a , 2b – 4b ) of the ligands with NaSCN and NaClO₄ have been prepared. The NaClO₄ complexes of 3 and 4 ( 3b and 4b ) form heteronuclear tritopic crystalline complexes with Ni²⁺ cations of stoichiometry 2 : 1 : 1 (Na⁺ : Ni²⁺ : ligand). A homonuclear monotopic Ni²⁺ complex has also been prepared by the reaction with Ni(CH₃COO)₂ · 6H_2O. The UV-VIS spectra of 2 – 4 and their NaClO₄ complexes ( 2b – 4b ) are studied in different solvents including acidic and basic media. In polar solvents, tautomeric equilibria (phenol–imine, O–H…︁N and ketoamine, O…︁H–N forms) are present, as supported by the UV-VIS data.