Vanadium pentaoxide

Chemical Designations - Synonyms Vanadic anhydride. Vanadium pentaoxide Chemical Formula ... 

Calcium, Vanadium pentaoxide See Vanadiiun(V) oxide Calcium, etc. 

The reaction of olefin epoxidation by peracids was discovered by Prilezhaev [235]. The first observation concerning catalytic olefin epoxidation was made in 1950 by Hawkins [236]. He discovered oxide formation from cyclohexene and 1-octane during the decomposition of cumyl hydroperoxide in the medium of these hydrocarbons in the presence of vanadium pentaoxide. From 1963 to 1965, the Halcon Co. developed and patented the process of preparation of propylene oxide and styrene from propylene and ethylbenzene in which the key stage is the catalytic epoxidation of propylene by ethylbenzene hydroperoxide [237,238]. In 1965, Indictor and Brill [239] published studies on the epoxidation of several olefins by 1,1-dimethylethyl hydroperoxide catalyzed by acetylacetonates of several metals. They observed the high yield of oxide (close to 100% with respect to hydroperoxide) for catalysis by molybdenum, vanadium, and chromium acetylacetonates. The low yield of oxide (15-28%) was observed in the case of catalysis by manganese, cobalt, iron, and copper acetylacetonates. The further studies showed that molybdenum, vanadium, and... 

Sulfuric Acid. Essentially all sulfuric acid manufactured in this industry is produced by the contact process, in which SO2 and oxygen contact each other on the surface of a catalyst (vanadium pentaoxide) to form SO3 gas. Sulfur trioxide gas is added to water to form sulfuric acid. The sulfur dioxide used in the process is produced by burning elemental sulfur in a furnace. 

Selective oxidation at C-2 of 3-deoxyaldonic acids by the action of sodium perchlorate in the presence of vanadium pentaoxide has been used for the preparation of deoxyketoaldonic acids, although low yields of pure compounds are obtained. The necessary 3-deoxyaldonic acids may be prepared by a cyanohydrin chain-extension reaction. Several syntheses have been reported for 3-deoxy-D-araZu rao-hept-2-ulosonic acid starting from 2-deoxy-D-arabino hexose 310,311 DAHP (122) has also been similarly prepared.312... 

Chloric acid, in conjunction with catalysts (particularly vanadium pentaoxide), is used for the oxidation of aldonic acids or lactones to the 2-glyculosonic acids. Thus, D-glucono-1,4-lactone (9) and potassium D-galactonate in methanol, in the presence of phosphoric acid and vanadium pentaoxide, are oxidized by chloric acid to methyl D-arabino-2-hexulosonate (10) and methyl D-/yxo-2-hexulosonate, respectively.38 At moderate temperatures in the absence of a catalyst, aldoses, ketoses, and sucrose are inert to the action of chlorates over a several weeks time period 39 bromates in alkaline solution also exert no oxidative action (Scheme 5). 

The preparation of water-soluble starch is the major practical aim of higher-level irradiations of starch. If starch alone is irradiated the effect of irradiation is dose-dependent, but the dose should not exceed 20-30 X 106 rad, otherwise dextrins are produced.232 233 The irradiation of starch in aqueous solution after pretreatment with hypochlorous acid is a patented procedure.234 Irradiation with a similar dose in the presence of vanadium pentaoxide has also been patented.235... 

The deactivation of the catalyst observed in Stage II is probably caused by the sintering of the vanadium oxide layer. The results of our previous work [13] show that reoxidation of Pd 0) is only possible with highly dispersed vanadium oxide. Catalysts on bulk vanadium pentaoxide show rapid deactivation due to the fact that reoxidation of Pd(0) hardly proceeds. Also catalysts supported on silica show rapid deactivation, as a result of the low dispersion of vanadium oxide on silica. 

VANADIUM DUST and FUME (ACGIH) VANAD-IUM(V) OXIDE VANADIUM PENTAOXIDE VANADIUMPENTOXID (GERMAN) VANADIUM PENTOXIDE, non-fused form (DOT) VANADIUM-PENTOXYDE (DUTCH) VANADIUM, PENTOXYDE de (FRENCH) WANADU PIECIOTLENEK (POLISH)... 

VANADIUM BROMIDE see VEKOOO VANADIUM CHLORIDE see VEFOOO VANADIUM(III) CHLORIDE see VEPOOO VANADIUM COMPOUNDS see VCZOOO VANADIUM DUST and FUME (ACGIH) see VDUOOO VANADIUM DUST and FUME (ACGIH) see VDZOOO VANADIUM (OSHA) see VDZOOO VANADIUM OXIDE see VEAOOO VANADIUM(V) OXIDE see VDUOOO VANADIUM OXYTRICHLORIDE see VDPOOO VANADIUM PENTAOXIDE see VDUOOO VANADIUMPENTOXID (GERMAN) see VDUOOO VANADIUM PENTOXIDE (dust) see VDUOOO VANADIUM PENTOXIDE (fume) see VDZOOO... 

In acute exposures, respiratory disease may be limited to interstitial inflammation of the alveolar epithelium, leading eventually to emphysema or pulmonary fibrosis (Cooper et al. 1982 Dungworth 1989 Stokinger 1981 Wedeen 1992). In studies of the pulmonary effects of airborne uranium dust in uranium miners and in animals, the respiratory diseases reported are probably aggravated by the inhalable dust particles (the form in which uranium is inhaled) toxicity because most of the respiratory diseases reported in these studies are consistent with the effects of inhaled dust (Dockery et al. 1993). In some of these instances, additional data from the studies show that the workers were exposed to even more potent respiratory tract irritants, such as silica and vanadium pentaoxide (Waxweiler et al. 1983). 

Deactivation is not only a problem for oxidation catalysts in combustion of bio-fuel, also SCR catalysts used in biomass fined boilers are deactivated. Andersson et al. [8] investigated the deactivation of SCR catalysts in a couple of different large scale bio-fuelled boilers. The SCR catalyst works at lower temperature (not above 400 C). According to the authors, no loss of surface area occurs and the deactivation is explained by adsorption of gaseous potassium on acidic site of the catalyst. The catalyst can only be partly regenerated by washing m acidic solution. The reason for this difference between precious metal based oxidation catalyst and vanadium pentaoxide... 

Calcium, Vanadium pentaoxide See Vanadimn(V) oxide Calcimn, etc. 

Bidk vanadium pentaoxide is quite active but low selective catalyst of hydrocaibons partial oxidation. It was established by XRD that the higher content of the phosphorus additive in it [12] the weaker peaks attributed to V2O) in bulk catalysts and, simultaneously, P-VOPO4 phase reflections appeared. The latter became the major component of VPO catalyst at fp > 0.67. The constituents of the prepared sample were found to be also 6 0)2P207, VO(POj)2 and some amorphous compounds. At this takes place, all the cations were considered by authors [12] to be bonded in vanadyl groiqis V=0 and phosphorus atoms form Bronsted acidic center each. It has been found an increased concentration of phosphorus over the surface as compared to the biilk and the higher phosphorus content in the sample the grown bulk concentration of the reduced vanadium ions were observed. 

Vanadium Pentoxide Vanadic Anhydride Vanadium Pentaoxide ... 

Synonyms/Trade Names Divanadium pentoxide dust. Vanadic anhydride dust. Vanadium oxide dust. Vanadium pentaoxide dust. Other synonyms vary depending upon the specific vanadium compound. 

Vanadium (lll)-2,4-pentanedionate. See Vanadium tris acetyl acetonate Vanadium pentaoxide. See Vanadium pentoxide Vanadium pentoxide... 

Vanadium (V) oxide Vanadium pentaoxide Vanadium pentoxide (dust) Vanadium pentoxide (fume) Vanadium pentoxide, nonfused... 

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