Ytterbium nitrate

In 1907 Georges Urbain separated ytterbia into two constituents. By repeated fractional crystallization of ytterbium nitrate from nitric acid solution, he obtained two oxides with different properties. One of these he named neoytterbia in order, as he said, to leave to the illustrious... 

The nature of the thermal decomposition of thalium peroxides has been investigated. A similar study of thulium and ytterbium nitrate tetrahydrates produced no evidence for the formation of anhydrous nitrates. The new Tm isotope was found to have a half life of 3.6 0.3 min. 

A 0.215 g (5.6x10 mol) ytterbium nitrate was dissolved in 50 rrrL distilled water, when rrrixing 0.2 rrrL acetylacetone in 2 mL ethanol was added arrd then the diluted solution of ammortia was slowly dropped to pH 6-6.5. The white precipitation was isolated by cerrtrifugatiorr, three times washed by distilled water and dried in a vacuum to a constarrt weight Yield 0.2 g (71%). M.p.l32°C. The substance was recrystallized from a berrzene and petroleum ether rrrix, M.p. 142-144°C. IR-spectrurrr, v, cm 3391 (H O), 1616 h 1524 (acac). Mass-spectrurrr, rrr/z 470 (M%... 

Acetylacetone was dissolved in a small volume of ethanol, mixed with water solution of ytterbium nitrate and the diluted solution of ammonia when mixing was slowly dropped under a pH control by use of pH-meter. At pH 5.7 the slight turbidity started, and at pH 6.0 the white precipitate was formed. We tried not to raise a pH higher than 6.5 since there can be a replacement of the acetylacetonate residues with a hydroxyl ... 

Intensive work with ytterbium was going on in Paris at the same time. Georges Ur-hain reported to the Paris Academy of Science on 4 " November 1907 (44 days before Auer s second report to the Vienna Academy) that he had performed a total of 800 fractionations of ytterbium nitrates, prepared from the mineral xenotime. Now he announced that he had divided ytterbium into two elements, for which he proposed the names neo-ytterbium Ny and lutecium Lu. The former was Marignac s element, now purified, the latter named after an old name for Paris, Lutetia Parisorum. 

An early report of a catalytic oxidation of an organic substrate by a simple lanthanide salt focused on the oxidizing ability of the nitrate anion, which was promoted by various ions (Girard and Kagan, 1975). Of the lanthanides studied (La, Sm, Eu, Tm, Yb), ytterbium nitrate gave the highest yield of benzils from benzoins ... 

Yb ytterbium-nitrate ion intermediate in the lanthanide-assisted oxida-... 

As anticipated from the complexation experiments, reaction of 4.42 with cyclopentadiene in the presence of copper(II)nitrate or ytterbium triflate was extremely slow and comparable to the rate of the reaction in the absence of Lewis-acid catalyst. Apparently, Lewis-acid catalysis of Diels-Alder reactions of p-amino ketone dienophiles is not practicable. 

To avoid excessive acid waste, lanthanide(III) triflates are used as recyclable catalysts for economic aromatic nitration. Among a range of lanthanide(III) triflates examined, the ytterbium salt is the most effective. A catalytic quantity (1-10 mol%) of ytterbium(III) triflate catalyzes the nitration of simple aromatics with excellent conversions using an equivalent of 69% nitric acid in refluxing 1,2-dichloromethane for 12 h. The only by-product of the reaction is water, and the catalyst can be recovered by simple evaporation of the separated aqueous phase and reused repeatedly for further nitration.12... 

Symmetrical and unsymmetrical benzoins have been rapidly oxidized to benzils in high yields using solid reagent systems, copper(II) sulfate-alumina [105] or Oxone-wet alumina [105, 106] under the influence of microwaves (Scheme 6.32). Conventionally, the oxidative transformation of a-hydroxy ketones to 1,2-diketones is accomplished by reagents such as nitric acid, Fehling s solution, thallium(III) nitrate (TTN), ytterbium(III) nitrate, ammonium chlorochromate-alumina and dayfen. In addition to the extended reaction time, most of these processes suffer from drawbacks such as the use of corrosive acids and toxic metals that generate undesirable waste products. 

The leach liquor is first treated with a DEHPA solution to extract the heavy lanthanides, leaving the light elements in the raffinate. The loaded reagent is then stripped first with l.Smoldm nitric acid to remove the elements from neodymium to terbium, followed by 6moldm acid to separate yttrium and remaining heavy elements. Ytterbium and lutetium are only partially removed hence, a final strip with stronger acid, as mentioned earlier, or with 10% alkali is required before organic phase recycle. The main product from this flow sheet was yttrium, and the yttrium nitrate product was further extracted with a quaternary amine to produce a 99.999% product. 

The metal dissolves in dilute and concentrated mineral acids. Evaporation crystallizes salts. At ordinary temperatures, ytterbium, similar to other rare earth metals, is corroded slowly by caustic alkalies, ammonium hydroxide, and sodium nitrate solutions. The metal dissolves in liquid ammonia forming a deep blue solution. 

At the end of the 19th century, Urbain, using the fractional crystallization method, prepared 60g of dysprosium oxide after 10,000 crystallizations then, in 1907, after 15,000 successive nitrate crystallizations from nitric solution, he separated lutetium and ytterbium. 

The Swiss chemist Jean Charles Galissard de Marignac (1817-1894), was the first in applying these spectroscopic methods. He was 23 years old when he embarked upon his quest for new rare-earth elements. He demonstrated in 1878 that "erbia was a complex mixture of at least two rare-earth elements, erbium and "ytterbium (Yb), by heating "erbium nitrate and extracting the decomposed salt with water. The little Swedish village Ytterby thus holds a distinguished place in the history of the rare-earth elements. 

SAFETY PROFILE Poison by ingestion and intraperitoneal routes. Experimental reproductive effects. When heated to decomposition it emits toxic fumes of NOx. See also YTTERBIUM, RARE EARTHS, and NITRATES. 

Owing to nitrates being bidentate, [La(Tp P )(N03)2] has 10-coordinate lanthanum, as has [La(Bp ° 2(N03)], but in [La(Bp( °0 y)2(CF3S03) the presence of a monodentate triflate causes lanthanum to be nine-coordinate. A number of studies have been made of ligands that are not tris(pyrazolyl)borates. [Yb(B(pz)4)3].EtOH has eight-coordinated ytterbium, one pyrazo-lylborate being bidentate. ... 

Ytterbium(III) Triflate as a Recyclable Catalyst for the Nitration of Arenes with Nitric Acid... 

Inspection of the data reveals a clear inverse correlation (with the exception of a few scattered data points) between the ionic radii of the various tripositive lanthanide ions and the extent of nitration whereby the the heavier congeners are the most effective. Thus lanthanum(IH) (Z = 57) triflate gave a 64% conversion of naphthalene to mononitronaphthalenes over lh, whereas the ytterbium(HI) (Z =70) triflate catalysed reaction gave a >95% conversion over the same time period. 

Characterisation was accomplished by IR spectroscopy. These materials exhibited the six stretches in the IR spectrum indicative of a symmetrically bound (i.e. inner sphere) bidentate nitrate species18 as well as the requisite (outer sphere) triflate stretches. For example, ytterbium(III) based analogue displayed characteristic nitrate absoptions at 1492, 1384, 1326, 814, 769 and 751 cm. The stretch at 1492 cm, asigned as the A] symmetrical stretch, is known to be critically dependent on the polarising power of the metal centre where increased polarisation of the nitrate leads to the observation of stretches at increased wavenumbers.18... 

Hafnium and zirconium mononitrate tris(triflate), [M(H20)x(N03)](0Tf)35 were prepared from their tetrachlorides in analogous fashion to the lanthanide salts. Much to our delight these (deliquescent) salts displayed A, nitrate stretching frequencies in their IR spectra at 1651 and 1650 cm1 respectively. Armed with this pleasing information and with a specific programme aim of nitrating o-nitrotoluene (ONT) to dinitrotoluenes (DNTs) with these catalyst types, (catalytic quantities of ytterbium(III) triflate were essentially ineffective for this transformation) hafnium(IV) and zirconium(IV) triflate were prepared as their hydrated salts via metathesis of their tetrachlorides with silver triflate in water. 

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