Neodymium oxide

Apparently the first and only report of neodymium oxide particle synthesis is due to Que etal. [294]. The method involved the well-known two-microemulsion 

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The reaction kinetics for the dehydrogenation of ethanol are also weU documented (309—312). The vapor-phase dehydrogenation of ethanol ia the presence of a chromium-activated copper catalyst at 280—340°C produces acetaldehyde ia a yield of 89% and a conversion of 75% per pass (313). Other catalysts used iaclude neodymium oxide and samarium hydroxide (314). 

Neodymium oxide [1313-97-9] M 336.5, m 2320°. Dissolved in HCIO4, ppted as the oxalate with doubly recrystd oxalic acid, washed free of soluble impurities, dried at room temperature and ignited in a platinum crucible at higher than 850° in a stream of oxygen [Tobias and Garrett J Am Chem Soc 80 3532 1958]. 

The titration of silica-alumina acid sites with neodymium oxide is clearly seen in Figure 4. The relative acid strength, as estimated by the 2,3DMB2/4MP2 ratio during 2MP2... 

The reduction diffusion process has also been used for the production of powders of the magnetic neodymium-iron-boron alloy (Nd15Fe77B8). The reaction involves use of a powder mix of neodymium oxide, iron, ferroboron and calcium. The reaction is conducted by heating the powder charge mixture at 1200 °C for 4 h under vacuum. Neodymium-iron-boron alloys are much more prone to oxidation than samarium-cobalt alloys and a proprietary leaching procedure is used for the separation of the alloy and calcium oxide. 

The perchlorate, prepared from neodymium oxide and perchloric acid [1] was purified and isolated as the salt tetrasolvated with acetonitrile [2], which has not been found to be shock-sensitive. On vacuum drying at 80°C/24h, it is converted to the disolvated salt which is very shock-sensitive and a 1 g sample exploded violently in a hand-held flask [3], Other examples of partially desolvated perchlorate salts becoming friction- and shock-sensitive are known [4], (The disolvate is very close to zero oxygen balance). 

See also Nd YAG entries Neodymium oxide, for oxidizing iron in glass, 7 343 Neoflon, 7 641 Neoflon AP, 7 641 Neoglaziovia variegata, 11 296 Neohesperidin dihydrochalcones (DHC), 12 42 24 240-241... 

Neodymium oxide (Nd O ) is a light-blue powder used to color glass and as a pigment for ceramics. It is also used to make color TV tubes. 

Heating the ore with sulfuric acid converts neodymium to its water soluble sulfate. The product mixture is treated with excess water to separate neodymium as soluble sulfate from the water-insoluble sulfates of other metals, as well as from other residues. If monazite is the starting material, thorium is separated from neodymium and other soluble rare earth sulfates by treating the solution with sodium pyrophosphate. This precipitates thorium pyrophosphate. Alternatively, thorium may be selectively precipitated as thorium hydroxide by partially neutralizing the solution with caustic soda at pH 3 to 4. The solution then is treated with ammonium oxalate to precipitate rare earth metals as their insoluble oxalates. The rare earth oxalates obtained are decomposed to oxides by calcining in the presence of air. Composition of individual oxides in such rare earth oxide mixture may vary with the source of ore and may contain neodymium oxide, as much as 18%. 

Neodymium oxide is produced from the two principal rare earth minerals, monazite, and bastnasite. The oxide is obtained as an intermediate in the recovery of neodymium metal (See Neodymium). 

Neodymium oxide dissolves in strong mineral acids forming corresponding neodymium salts ... 

A true colorless glass such as an optical glass must be made with very low iron materials since decolorizing agents would reduce the transmission. The main physical decolorizers are manganese, selenium, cobalt and neodymium oxides. Manganese with a little cobalt is effective in complimenting the iron in the ferric state. 

The third oxide used for physical decolorizing is neodymium oxide. Its absorption curve closely compliments an average mixture of ferrous and ferric oxides especially with the strong absorption band at 589 nm. Neodymium oxide is also stable against any state of oxidation change in the furnace. Neodymium is exceptionally good as a decolorizer for potassium silicate and lead glasses. If the redox balance is not quite correct for the... 

It is important to calcine at the appropriate temperature to enhance the deactivation and the catalysis for the ceria-modified HM.50,51 The catalyst calcined at 300 °C had no catalytic activity. The activity for the isopropylation of naphthalene appeared over the catalyst calcined at 450 °C and reached the maximum at 550 °C. However, the activity decreased at a temperature of 700 °C. These results show that calcination at an appropriate temperature is necessary to keep the HM pores open. The selectivity for 2,6-DIPN was as high as 70% over the catalysts regardless of their calcination temperature. These phenomena show that the isopropylation proceeds inside HM pores. This selective deactivation of HM pores was limited to modification with ceria. The modification with other rare-earth metal oxides, such as lanthanum and neodymium oxides, also deactivated the external acid sites but choked the HM pore to result in low catalytic activity. The isomerization of 4,4 -DIPB was also prevented by the ceria modification of HM in the isopropylation of biphenyl.49... 

Pearson and colleagues (135) studied laser oscillation in glasses from the system calcium oxide, lithium oxide, boron oxide, doped with neodymium oxide. These glasses have been called the Calibo glasses. 

Spectrum of the Glowing Oxide.—Neodymium oxide is one of the very few solids with a discontinuous spectrum. The spectrum which was known long before neodymium was separated from its fellow element praesodymium, was briefly described by Bunsen1 in 1864, who in the same communication mentions the discovery by Bahr2 of the similarly banded spectrum of erbium oxide. Thus far, however, no thorough-going study seems to have been made of this class of spectrum. 

A unique variant of catalyst preformation in the absence of dienes was described by Enichem in an early patent on Nd-BR. The active Nd catalyst was prepared by the reaction of neodymium oxide with carboxylic acid and (BuCl in vaseline at 80 °C. Subsequently, aqueous HC1 was added at 80 °C. Finally, the addition of the aluminum alkyl co catalyst yielded the active Nd catalyst [389,390]. 

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