Standard test method for total molybdenum in fresh alumina-base catalysts

Journal Article · Tue Jan 01 04:00:00 EST 1980 · Annu. Book ASTM Stand.; (United States)

OSTI ID:6537138

This method covers the determination of molybdenum in alumina-base catalysts and has been cooperatively tested at molybdenum concentrations from 8 to 18 weight %, expressed as MoO/sub 3/. Any component of the catalyst other than molybdenum such as iron, tungsten, etc., which is capable of being oxidized by either ferric or ceric ions after being passed through a zinc-amalgam reductor column (Jones Reductor) will interfere. The catalyst is digested in hot sulfuric acid to dissolve molybdenum, destroy organic matter, and to expel nitrates if present. The acid solution is diluted and passed through an amalgamated zinc column (Jones reductor) into a receiving flask containing an excess of ferric ammonium sulfate. The column quantitatively reduces the molybdenum (Mo/sup -6/ to Mo/sup +3/) which in turn is reoxidized in the receiving flask according to the reaction: Mo/sup +3/ + 3Fe/sup +3/ ..-->.. Mo/sup +6/ + 3Fe/sup +2/. The ferrous ion produced (three per Mo/sup +3/ oxidized) is titrated with standard ceric sulfate solution in the presence of ferroin indicator. The indicator undergoes a color change (pink to colorless or very faint blue-green) in the presence of excess ceric ion. The amount of Fe/sup +2/ titrated in the reaction: Fe/sup +2/ + Ce/sup +4/ ..-->.. Fe/sup +3/ + Ce/sup +3/ is a direct measure of Mo/sup +6/ concentration. This method sets forth a procedure by which catalyst samples can be compared either on an interlaboratory or intralaboratory basis. It is anticipated that catalyst producers and users will find this method of value.

• OSTI ID: 6537138
• Journal Information: Annu. Book ASTM Stand.; (United States), Journal Name: Annu. Book ASTM Stand.; (United States) Vol. 25; ISSN ASTSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400102* -- Chemical & Spectral Procedures
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
AMMONIUM COMPOUNDS
AMMONIUM SULFATES
CATALYST SUPPORTS
CATALYSTS
CERIUM COMPOUNDS
CERIUM SULFATES
CHALCOGENIDES
CHEMICAL ANALYSIS
CHEMICAL REACTIONS
ELEMENTS
HYDROGEN COMPOUNDS
INORGANIC ACIDS
IRON COMPOUNDS
IRON SULFATES
METALS
MOLYBDENUM
OXIDES
OXYGEN COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
RARE EARTH COMPOUNDS
REFRACTORY METALS
SULFATES
SULFUR COMPOUNDS
SULFURIC ACID
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
ZINC