Robert L. McBeth

OXIDATION STATES AND COMPLEX IONS OF URANIUM IN FUSED CHLORIDES AND NITRATES

Oxidation states of uranium in fused LiCl-KCl eutectic, pyridinium chloride, and LiNO/sub 3/-KNO/sub 3/ eutectic were charaeterized spectrophotometrically. The (III), (IV), and (VI) oxidation states of uranium are stable in LiCi-KCl eutectic. The (IV) and (VI) oxidation states have been observed in pyridinium chloride. In LiNO/sub 3/KNO/sub 3/ eutectic the (III) and (IV) states are oxidized to the (VI) oxidation state. It was found that Al as well as U metal reduces U(N) to U(III) while Mg metal reduces U(III) to U(O) in LiCl-KCl eutectic. On the basis of these experiments the U(IIl)-U(O) standard potential versus a l M Pt reference electrode can be predicted to lie between- 1.77 and-258 v. The U(IV)-U(III) potential versus the same electrode can be expected to be more positive than -1.77 v. Spectrophotometric evidence indicates that U(IV) changes its co-ordination number from six to eight in going from fused pyridinium chloride to LiCl-KCl eutectic. Changes were observed in the UO/sub 2/ (II) spectrum on addition of chloride ion to UO/sub 2/(II) solutions in LiNO/sub 3/-KNO/sub 3/ eutectic which were correlated with the formation of chlorocomplexes of uranyl ion. (auth)

Phenolic ethers in the organic polymer of the Murchison meteorite

Seven phenolic acids and many nonphenolic organic acids, including large amounts of meta-hydroxy (3-hydroxy) benzoic acid and 3-hydroxy-1,5-benzene-dicarboxylic acid, were obtained from the organic polymer of the Murchison C2 chondrite upon oxidation with alkaline cupric oxide. The phenolic acids apparently were derived from phenolic ethers in the polymer, which in turn probably were formed from carbon monoxide and hydrogen by catalytic Fischer-Tropsch type reactions in the solar nebula. In contrast, terrestrial polymers such as lignin, humic acid, and coal yield mainly para-hydroxy (4-hydroxy) benzene derivatives by the same oxidation procedure.

Artificial coalification study: Preparation and characterization of synthetic mecerals

Abstract It was found that lignin heated with clay minerals at 150°C for 2–8 months in the absence of oxygen was readily transformed into an insoluble material resembling low rank coals. The H/C and O/C ratios were in the natural evolutionary range found for vitrinites with the samples from longer reaction times resembling the vitrinites of higher rank. The chemical and physical characterization of the artificial products indicated that their basic chemical structure closely resembles that of vitrinite macerals. Simple pyrolysis of only the lignin at 350–400°C yielded very different products with a substantialy lower H/C ratio and a higher O/C ratio than either transformed lignin with clay or vitrinites of any rank. Such products were found to correspond to fusinite in chemical structure. Macromolecules similar to alginites or type I kerogens were produced by heating fatty acids at 200°C with clays. The present study suggests that coal macerals could have been produced directly from the biological source material via catalytic thermal reactions.

Thermal catalytic transformation of pentacyclic triterpenoids: Alteration of geochemical fossils during coalification

Abstract To elucidate the possible natural evolutionary pathways for the transformation of pentacyclic triterpenoids, three terpenoid samples, Δ 2 -allobetulene, tetranormethylallobetulheptaene and fernenes were heated independently at 150°C for 7 weeks with montmorillonite clay. Common products from these reactions consisted of di, tri-, tetra-, and pentacyclic hydroaromatic and aromatic hydrocarbons, which are commonly found in higher rank coals. C-ring cleaved (8,14-seco) aromatic terpenoid derivatives were also found in the thermal catalytic reaction products of Δ 2 -allobetulene. Such compounds could be important intermediates in the formation of bicyclic hydrocarbons from pentacyclic triterpenoids.

Investigation of aqueous sodium dichromate oxidation for coal structural studies

Abstract To determine optimum conditions, the aqueous Na 2 Cr 2 O 7 oxidation as applied to coals, coal products, model compounds and polymers was investigated in detail. It was found that this oxidation preferentially attacks aliphatic and alicyclic methylene linkages with minimum degradation of most aromatic ring systems, as suggested earlier. However, aliphatic-rich macromolecules, probably related to exinites, were found to be selectively oxidized and isolated as long-chain aliphatic dicarboxylic acids under buffer-controlled oxidation conditions.

Evaluation of lignin and cellulose contributions to low-rank coal formation by alkaline cupric oxide oxidation

Oxidation with alkaline cupric oxide has been combined with solid-state 13C-n.m.r. spectroscopy to evaluate the cellulose and lignin input to the formation of low rank coals. Model studies carried out on lignin-cellulose mixtures, carbonified cellulose, synthetic coals and synthetic humic acids (melanoidins) have established m-hydroxybenzoic acid as a source indicator for cellulose. This product has been found specifically in the oxidation of bio- and geo-macromolecules containing cellulose and/or thermally altered cellulosic material and is chemically distinct from the characteristic oxidation products of lignin-derived materials. Systematic changes in the distribution of the major oxidation products from lignin provide a chemical fingerprint which, in general, can be utilized to trace the thermal history of the sample. Analysis of two lignite coals from the northern hemisphere has demonstrated their predominantly lignitic origin. On the other hand, a Victorian brown coal (pale lithotype) sample is shown to contain a significant amount of highly transformed carbohydrate materials which are presumably incorporated into the macromolecular structure as humic acid derivatives.

OXIDATION STATES OF THE ELEMENTS AND THEIR POTENTIALS IN FUSED‐SALT SOLUTIONS: THE ACTINIDE ELEMENTS*

Experimental results concerning the oxidation states and potentials of the actinide elements in fused nitrates and chlorides are summarized. Measurements on the absorption spectra of Pu and Am in LiCl--KCI eutectic are reviewed (C.J.G.)

Hydroxyl formation accompanying defect center production in proton and deuteron bombarded aluminum oxide

The defect center produced in Al2O3 by energetic neutron or electron bombardment which gives rise to a 205 nm (6.03 eV) absorption band appears with two to three orders of magnitude higher intensity in proton and deuteron bombarded samples compared to either neutron, electron or heavier ion bombardments. The infrared spectra of this system is used to show that the formation of OD or OH provides an additional mechanism of defect production. (AIP)

Reactions of Coal and Model Coal Compounds in Room Temperature Molten Salt Mixtures

A 2:1 AlCl/sub 3/-pyridinium chloride molten salt solution was used as the reaction medium for the alkylation of diphenylethane and a bituminous coal by 2-propanol. Probably accompanying the room temperature Friedel-Crafts alkylation is a reduction of C=O to -C-OH. Completely deuterated 2-propanol did not react at all with the pyridinium ring. The pyridinium chloride serves to lower the temperature at which the AlCl/sub 3/ is able to catalyze the reactions. The pyridinium chloride also catalyzes the Friedel-Crafts alkylation.

Absorption spectrum, vapor pressure equations and thermodynamics of NpCl4

Abstract The absorption spectrum of NpCl4 vapor has been obtained at temperatures up to 632°C. The vapor pressure of NpCl4 was determined spectroscopically in the range 468°–632°C. These values were combined with Knudsen Cell measurements in the range 279°–423°C and Bourdon gauge measurements in the range 436°–601°C to give the following equations for the vapor pressure of NpCl4. log P mm =−9932/° K +13·54(279–537° C ) and log P mm =−6471/° K +9·23(539–632° C ) The calculated thermodynamic values are: ΔH ( sublimation ) =45·3±0·4 kcal/mole ΔS ( sublimation ) =61·7±0·5 cal /°/ mole ΔH( vaporization )=29·5±0·2 kcal/mole ΔS( vaporization )=42·1±1·7 cal /°/ mole Attempts to identify NpCl5 from the reaction NpCl 4 (s,l)+ 1 2 Cl 2 (g)→ NpCl 5 (g) were unsuccessful.