THE EFFECT OF THE NATURE OF THE A-CATION IN ALKALINE EARTH TITANATES, ATIO3 (A = CA, SR, BA), AND THE CALCINATION TEMPERATURE (600 °C, 700 °C) ON THE CATALYTIC PERFORMANCE FOR THE OXIDATION OF 2-(METHYLTHIO)-BENZOTHIAZOLE IS REPORTED. THE SOLIDS WERE CHARACTERIZED BY NITROGEN ADSORPTION ISOTHERMS, POWDER X-RAY DIFFRACTION, O2 TEMPERATURE-PROGRAMMED DESORPTION, TEMPERATURE-PROGRAMMED REDUCTION, FOURIER TRANSFORM INFRARED SPECTROSCOPY, AND DIFFUSE REFLECTANCE SPECTROSCOPY/UV?VIS TECHNIQUES. A LARGER EXTENT OF THE PEROVSKITE-TYPE STRUCTURE WAS OBTAINED FOR THE ALKALINE EARTH TITANATES AT A CALCINATION TEMPERATURE OF 700 °C. THE INCREASES IN THE CATALYTIC OXIDATION WITH THE IONIC RATIO OF THE A-CATION (BATIO3 > SRTIO3 > CATIO3) WAS ATTRIBUTED TO THE WELL-DEFINED PEROVSKITE STRUCTURE WITH A LOWER EXTENT OF SEGREGATED PHASES. FOR THE CATALYSTS CALCINED AT 700 °C, A LARGER CONVERSION LEVEL (>75 MOL%) AND SELECTIVITY TOWARDS THE CORRESPONDING SULFONE (>95 MOL%) WAS ACHIEVED AT A REACTION TEMPERATURE OF 60 °C USING H2O2 (30%) AS AN OXIDANT. BATIO3 CALCINED AT 700 °C, PROVIDED THE BETTER CATALYTIC PERFORMANCE AND NO ACTIVITY LOSS AFTER FOUR REUSES, INDICATIVE OF THE LARGEST STABILITY IN THE REACTION MEDIUM.

THIS WORK FOCUSES ON DEVELOPING NOVEL IRON-BASED SELF-LUBRICATING COMPOSITES REINFORCED WITH TI2SNC MAX PHASE PRODUCED BY POWDER METALLURGY. TWO AMOUNTS OF TI2SNC (5 AND 10 VOL%) AND THE ADDITION OF 10 VOL% GRAPHITE WERE EVALUATED. THE MICROSTRUCTURE REVEALED A PARTIAL REACTION BETWEEN THE MATRIX AND THE TI2SNC, EXHIBITING A DEGREE OF DISSOCIATION IN THE PRESENCE OF GRAPHITE, LEADING TO THE PRECIPITATION OF CARBIDES. THE ADDITION OF THE MAX PHASE SIGNIFICANTLY IMPROVED THE HARDNESS AND COMPRESSION STRENGTH. THE DRY COEFFICIENT OF FRICTION WAS AROUND 0.12 FOR FE + 5TI2SNC + 10GR, SHOWING A REMARKABLE REDUCTION IN WEAR RATE UP TO 85 % COMPARED TO PURE IRON. THE RESULTS DEMONSTRATE A SYNERGISTIC EFFECT BETWEEN THE MAX PHASE AND GRAPHITE, ENHANCING TRIBOLOGICAL PERFORMANCE AND WEAR RESISTANCE.

ENVIRONMENTALLY FRIENDLY HETEROGENEOUS SOL-GEL LA2O3-AL2O3 MATERIALS WITH NO ALKALINE OR ALKALINE-EARTH METALS WERE SYNTHESIZED TO BE USED AS CATALYSTS FOR BIODIESEL PRODUCTION BY A TRANSESTERIFICATION REACTION OF CANOLA OIL. THE EFFECT OF THE LA2O3 CONTENT (0, 3, 5, 7, AND 10 WT%) ON THE CATALYTIC PERFORMANCE OF THE LA2O3-AL2O3 MIXED OXIDES, AS WELL AS THE TEXTURAL, STRUCTURAL, AND SURFACE PROPERTIES, IS REPORTED. IT WAS FOUND THAT LA2O3 LOADING INCREASES THE NUMBER AND STRENGTH OF BASIC SITES UP TO 7% LA2O3-AL2O3 CATALYST WITH AN LA2O3 MONOLAYER FORMATION WITH 0.23 MMOL HIGHLY DISPERSED LA ATOMS OVER AL2O3 IS REPORTED. A CORRELATION BETWEEN CATALYTIC PERFORMANCE, INFORMED AS BIODIESEL PRODUCTION WITH BASICITY, CARBONATION DEGREE, AND LA2O3 DISPERSION IS OBTAINED. THE EXTENT OF BIODIESEL PRODUCTION (45% AT 65 A DEGREES C AND 5 H OF REACTION TIME), UNDER MILD REACTIONS CONDITIONS, FOR THE MONOLAYER LA2O3 ALUMINA CATALYST IS THE HIGHEST REPORTED UP NOW FOR NONTOXIC HETEROGENEOUS CATALYSTS.

LA2O3 MONOLAYER CATALYSTS WITH 90% COVERAGE ON AL2O3 AND 71% ON ZRO2 WERE SUCCESSFULLY OBTAINED BY A SOL?GEL METHOD AND THE CATALYTIC PERFORMANCE EVALUATED AS FATTY ACID METHYL ESTERS (FAME) PRODUCTION IN A CANOLA OIL TRANSESTERIFICATION REACTION SHOW DIFFERENCES UPON THE NATURE AND EXTENT OF BASIC SITES. THE LA2O3 MONOLAYER DOES NOT MODIFY STRONGLY THE TEXTURAL PROPERTIES OF THE AL2O3 AND LARGER STRUCTURAL CHANGES ARE DETECTED ON ZRO2. FOR THE LA2O3-AL2O3 MONOLAYER CATALYST, THE INTER-DIFFUSION AL3+/LA3+ CATION MODIFY THE NATURE OF THE ACIDITY AND INCREASES THE BASICITY OF THE AL-O-LA SPECIES, WHEREAS FOR THE LA2O3-ZRO2 MONOLAYER CATALYST, APPEARANCE OF TETRAGONAL ZRO2 STRUCTURE WITH LARGER BASICITY IS DETECTED. THE EFFECT OF THE NATURE OF THE SUPPORT IN THE CATALYTIC PERFORMANCE IN FAME PRODUCTION OF THE LA2O3-ZRO2 AND LA2O3-AL2O3 MONOLAYER CATALYST INFORMED AS FAME % (60% AT 5?H AND 65?°C) FOR THE LA2O3-ZRO2 IS ATTRIBUTED TO THE PRESENCE OF THE NEW MEDIUM STRENGTH BASIC SITES AND THE M-ZRO2 STRUCTURE, WHEREAS THE LOWER BASICITY OF THE LA2O3-AL2O3 EXPLAIN THE LOWER FATTY ACID METHYL ESTERS PRODUCTION (45% AT 5?H AND 65?°C).

DIFFERENT LA2O3 CONTENTS (0, 1, 2, 3, AND 5 WT%) WERE USED TO PREPARED LA2O3-ZRO2 MIXED OXIDES CALCINED AT 600 DEGREES C BY THE SOL-GEL METHOD. THE CATALYTIC ACTIVITY WAS MEASURED AS BIODIESEL PRODUCTION FROM CANOLA OIL THROUGH A TRANSESTERIFICATION REACTION. THE CHARACTERIZATION RESULTS INDICATE THAT THE LA2O3 MONOLAYER FORMATION AND EXTENT OF BASICITY OF M-ZRO2 HAVE A LARGE INFLUENCE ON BIODIESEL PRODUCTION. GREATER BIODIESEL CONVERSION (56% AT 4 H) WAS OBTAINED WITH THE 3% LA2O3-ZRO2 CATALYST IN THE PRESENCE OF BASIC SITES AND THE FORMATION OF A MONOLAYER OF LA2O3. THE DECREASE IN THE CATALYTIC ACTIVITY FOR 5% LA2O3-ZRO2 RESULTED FROM THE LOSS OF ACTIVE SITES ON THE CATALYST BECAUSE OF AGGLOMERATION, WHICH WAS SUGGESTED BY XPS AND THE ISOELECTRIC POINT. THE KINETIC DATA FIT TO A PSEUDO-FIRST ORDER CONSTANT, AND THE LARGEST KINETIC CONSTANT CORRESPONDS TO 3% LA2O3-ZRO2, CURRENTLY THE LARGEST HETEROGENEOUS NON-ALKALINE METAL CATALYST REPORTED FOR A TRANSESTERIFICATION REACTION. (C) 2017 SCIENCE PRESS AND DALIAN INSTITUTE OF CHEMICAL PHYSICS, CHINESE ACADEMY OF SCIENCES. PUBLISHED BY ELSEVIER B.V. AND SCIENCE PRESS. ALL RIGHTS RESERVED.

THE EFFECT OF THE ZRO2 LOADING WAS STUDIED ON SPHERICAL SIO2@ZRO2-CAO STRUCTURES SYNTHETIZED BY A SIMPLE ROUTE THAT COMBINES THE STÖBER AND SOL-GEL METHODS. THE TEXTURE OF THESE MATERIALS WAS DETERMINED USING SBET BY N2 ADSORPTION, WHERE THE INCREMENT IN SIO2 SPHERES SURFACE AREAS WAS REACHED WITH THE INCORPORATION OF ZRO2. COMBINED THE CHARACTERIZATION TECHNIQUES OF USING DIFFERENT ALCOHOLIC DISSOLUTIONS OF ZIRCONIUM (VI) BUTOXIDE 0.04 M, 0.06 M, AND 0.08 M, WE OBTAINED SIO2@ZRO2 MATERIALS WITH 5.7, 20.2, AND 25.2 WT % OF ZR. TRANSMISSION ELECTRON MICROSCOPY (TEM) ANALYSIS ALSO UNCOVERED THE SHAPE AND REPRODUCIBILITY OF THE SIO2 SPHERES. THE PRESENCE OF ZR AND CA IN THE CORE-SHELL WAS ALSO DETERMINED BY TEM. X-RAY DIFFRACTION (XRD) PROFILES SHOWED THAT THE C-ZRO2 PHASE CHANGED IN TO M-ZRO2 BY INCORPORATING CALCIUM, WHICH WAS CONFIRMED BY RAMAN SPECTROSCOPY. THE PURITY OF THE SIO2 SPHERES, AS WELL AS THE PRESENCE OF ZR AND CA IN THE CORE-SHELL, WAS ASSESSED BY THE FOURIER TRANSFORM INFRARED (FTIR) METHOD. CO2 TEMPERATURE PROGRAMMED DESORPTION (TPD-CO2) MEASUREMENTS CONFIRMED THE INCREMENT IN THE AMOUNT OF THE BASIC SITES AND STRENGTH OF THESE BASIC SITES DUE TO CALCIUM INCORPORATION. THE CATALYST REUSE IN FAME PRODUCTION FROM CANOLA OIL TRANSESTERIFICATION ALLOWED CONFIRMATION THAT THESE CALCIUM CORE@SHELL CATALYSTS TURN OUT TO BE ACTIVES AND STABLES FOR THIS REACTION.

THE PROMOTING EFFECT OF COBALT OXIDE ON ALUMINA-SUPPORTED CU OXIDE CATALYSTS FOR THE HYDROGENOLYSIS OF GLYCEROL WAS INVESTIGATED. A SERIES OF CO(Y)CU/AL2O3 OXIDE CATALYSTS WITH A FIXED CU LOADING OF 7 WT% AND A VARIABLE CO LOADING FROM 0 TO 1.5 WT% WAS PREPARED BY SUCCESSIVE WET IMPREGNATION. THE CATALYSTS WERE CHARACTERIZED BY X-RAY DIFFRACTION (XRD), NITROGEN SORPTION, TEMPERATURE PROGRAMMED REDUCTION (TPR), ULTRAVIOLET-DIFFUSE REFLECTANCE SPECTROSCOPY (UV-DRS), TEMPERATURE PROGRAMMED DESORPTION OF AMMONIA (TPD-NH3), AND X-RAY PHOTOELECTRON SPECTROSCOPY (XPS). THE CATALYSTS WERE TESTED IN A BATCH REACTOR AT 220 DEGREES C AND 5 MPA OF H-2. THE ACTIVITY OF THE CATALYSTS ON A PER MOLE OF CU BASIS INCREASED WITH CO CONTENT UP TO THE PLATEAU, AND SUBSEQUENTLY DECREASED AT HIGHER CO CONTENT. THE INCREASE OF ACTIVITY IS ATTRIBUTED TO THE COMBINED EFFECT OF THE DISTORTION OF THE OCTAHEDRAL GEOMETRY OF CUO BY THE PRESENCE OF COO AND THE INCREASE IN THE NUMBER OF SURFACE ACID SITES. IN CONTRAST, THE SUBSEQUENT DECREASE OF ACTIVITY AT HIGHER LOADING IS RELATED TO THE FORMATION OF LESS REDUCIBLE, LESS ACIDIC, AND LESS ACTIVE ALUMINATES. THE SELECTIVITY OF PRODUCTS DID NOT VARY SUBSTANTIALLY WITH CO LOADING, INDICATIVE OF THE EXISTENCE OF ACTIVE SITES OF SIMILAR CHARACTERISTICS ON ALL THE CATALYSTS. OVERALL, ALL THE CATALYSTS FAVORED THE ROUTE COMPRISING OF C-O HYDROGENOLYSIS FOLLOWED BY HYDROGENATION, AT THE EXPENSE OF THE PATHWAY INVOLVING C-C HYDROGENOLYSIS, LEADING TO THE PREDOMINANT FORMATION OF 1,2-PROPANEDIOL (1,2-PDO). THIS IS PROBABLY DUE TO THE PREVALENCE OF METALLIC ACTIVE SITES OVER ACIDIC SITES ON THE SURFACE, ENSURING THAT PARTIAL REMOVAL OF OXYGEN OCCURRED WITHOUT THE LOSS OF CARBON ATOMS.