Author: Matthew Peter HousePublisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 580
Book Description
Selective Oxidation of Methanol Over Iron Molybdate Catalysts
Author: Matthew Peter HousePublisher:
ISBN:
Category : Catalysis
Languages : en
Pages : 580
Book Description
Methanol Oxidation on Transition Elements Oxides
Author: Abdulmohsen AlshehriPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Methanol oxidation to formaldehyde is one of the most important industries in our lives; the reaction occurs on catalyst surface in heterogeneous catalysis. Iron molybdate is the current selective catalyst. However, molybdenum volatilises during methanol oxidation and leaving the catalyst with a low molybdenum ratio, which deactivates the catalyst, a 2.2 Mo: 1Fe iron molybdate catalyst was used instead the stoichiometric catalyst, while yield of formaldehyde cannot be 100%. The goal of this study is to find more selective and more productive catalyst than iron molybdate catalyst, the first step is to find another transition element as selective as molybdenum, because molybdenum is the selective part, and iron is the active part, the resulting iron molybdate catalyst is a selective catalyst to formaldehyde near molybdenum and active near iron. Experimentally, catalysts were prepared using co-precipitation method, however, some doped catalysts were papered by incipient wetness impregnation, also sol-immobilization was used to prepare nano-gold particles on the surfaces of few supports. Catalysts characterizations were carried out within several techniques for the surface analysis (XPS) and bulk analysis (XRD), also the surface area was measured by BET equipment. Raman too was used in this study, while micro-reactor was the reactor to determine selectivity and activity of each catalyst. When molybdenum replaced by vanadium, the catalyst yielded 100% formaldehyde at 200 oC; moreover, tungsten was selective. Likewise, iron was replaced by other active metals such as manganese, copper and bismuth, which are active. Nano-gold improved activity when doped on molybdenum oxide and iron molybdate supports.
The Partial Oxidation of Methanol to Formaldehyde Over Molybdenum-containing Catalysts
Author: Tsong-Jen YangPublisher:
ISBN:
Category : Catalysts
Languages : en
Pages : 288
Book Description
Selective Oxidation of Methanol on VSbO Sub 4 Catalysts
Author: I. PeshevaSelective Oxidation of Methanol on Mixed Oxide Catalysts
Author: Polina Yasenevaהכנה למבחן הבגרות (הכללי והדתי) בנושא "תולדות עם ישראל בדורות האחרונים" יחידה ו+ט - יחידת לימוד אחת, "ידע עם ומדינה" - 2 יחידות לימוד
Author: Metal Phosphate and Precious Metal Catalysts for Selective Oxidation
Author: Gareth Thomas WhitingPublisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
The main objective researched in this thesis involves the selective oxidation of methanol to formaldehyde, using metal phosphate based catalysts. Molybdenum and vanadium phosphate based catalysts have been prepared, thoroughly characterised and tested as active catalysts for the selective oxidation of methanol to formaldehyde. Initial investigations highlighted the relatively low activity of both metal phosphate catalysts, however, significant enhancements in the catalytic activity and formaldehyde selectivity of both materials have been achieved in this research, primarily by supporting molybdenum phosphate catalysts using a range of supports, and also promoting both molybdenum and vanadium pyrophosphates with transition metals. It was discovered that a catalyst of 10 wt% (MoO2)2P2O7 supported on SiO2 containing 1 mol% vanadium (as a promoter) achieved significantly higher formaldehyde per pass yields (>20 %) than MoO3 supported on SiO2 (reported in the literature) and comparable activity to that of the commercial iron molybdate catalyst. Due to the promotional effect of vanadium, and the known activity of V2O5 catalysts for the oxidation of methanol to formaldehyde, molybdenum promoted (VO2)2P2O7 catalysts were tested for this reaction and reported for the first time. Catalytic studies revealed that there is a direct correlation between molybdenum content and catalytic activity, indicating a synergistic effect of the two transition metals. The penultimate chapter of this thesis involves the use of supported mono- and bi-metallic gold(palladium) catalysts and their use in both CO oxidation and selective methanol oxidation. A novel method of maintaining considerably small Au(Pd) nanoparticle size (unlike the standard thermal treatment method) has been discovered by the Hutchings group at Cardiff Catalysis Institute, involving the removal of stabilising IV ligands with a solvent extraction method. Using high resolution microscopy and a range of characterization techniques, the nanoparticle size was attributed to the surprisingly high activity achieved for both CO oxidation and methanol oxidation to methyl formate, at low temperatures which, particularly in the case of methanol oxidation, is a remarkable discovery.
Author: Catherine Brookes
Author: Takaaki Ikuno
Author: Ling Zhou