Analysis of Toxic Aluminium Species in Natural Waters

Aluminium is known to be toxic to a wide range of aquatic organisms under certain conditions. Monomeric hydroxy ions have been found to be primarily responsible for aluminium aquatic toxicity.A survey of aluminium toxicity and a brief discussion of speciation schemes are presented. The fast reaction of Al³⁺ with pyrocatechol violet (PCV) followed by spectrophotometric analysis is a frequently used method for aluminium speciation. By using a flow system, one obtains fairly exact and reproducible control of the reaction time, and as a result it provides a direct method of analysis for free aluminium (including inorganic monomeric aluminium).The PCV-method has been adapted for the determination of aluminium in carbonate-rich natural waters using an improved buffering system. Thus it is possible to monitor aluminium concentrations in lake water as well as in pore water of the sediments of eutrophicated hardwater lakes that has been treated with aluminium salts as a restoration measure.     

Base-freie Tris(trimethylsilyl)methyl-Derivate des Lithiums,Aluminiums, Galliums und Indiums

Base-free Tris(trimethylsilyl)methyl Derivatives of Lithium, Aluminium, Gallium, and Indium Base-free LiR* (R*=-C(SiMe₃)₃) has been prepared from R*Cl and Li-metal in toluene at 85?90°C and used to synthesize the metallanes R*MMe₂ with M = Al, Ga and In, respectively. The NMR (¹H, ¹³C, ²⁹Si) and the vibrational spectra of these trisyl compounds have been discussed. AlCl₃ and LiR*(ratio 1 : 1) forms the metallate metallate Li[R*AlCl₃]. The triclinic unit cell (space group P1 ) consists of a centrosymmetric assoziate, formed by four Li[R*AlCl₃]- units with Al? Cl…?Li bridges, two pairs of Li-atoms differing in their chlorine-coordination and two disordered toluene molecules, inserted in the crystal lattice (R₁wR₂ =0,0444/0,1072). The reaction of GaCl₃ with LiR* (I :1) gives the unusual sesquichloride (R*Ga(Cl_1,33)Me_0,67)₃ in moderate yield. The X-ray structure determination shows a Ga₃Cl₃-skeleton with chairconformation and disordered, terminal gallium ligands (R₁/wR₂= 0,0646/0,2270).     

The Crystal Structure of Ba3Cu2Al2F16: a Relative of Ba4Cu2Al3F21

Ba₃Cu₂Al₂F₁₆ is monoclinic: a = 7.334(1)Å, b = 5.320(2)Å, c = 16.022(1)Å, β = 96.34(1)°, Z = 2. Its crystal structure was solved in the space group P2₁ (No. 4) from synchrotron X‐ray single crystal data using 2685 unique reflections (2639 with F_o/σ(F_o) > 4). The final R factor is 0.044. The structure consists of a succession along the c‐axis of the cell of three layers of two different kinds of sheets developing in the (a, b) plane. The first one, formulated [(AlF₅)₂]_∞^4— and hereafter named A, is built up from infinite cis‐chains of aluminium‐fluorine octahedra [AlF₆], linked by two vertices and distanced by a. The second one, formulated [Cu₂AlF₁₁]_∞^4— and named B, is bidimensional. It is constituted of distorted copper‐fluorine octahedra [CuF₆], linked by edges, which form infinite chains interconnected by three vertices of isolated [AlF₆] octahedra. The stacking sequence of the sheets is (A, B, B)_∞. The barium ions, 12‐coordinated, are inserted between the sheets. The crystal structure of Ba₃Cu₂Al₂F₁₆ is closely related to that of Ba₄Cu₂Al₃F₂₁. Only the proportion and the stacking sequence of the two kinds of sheets in the c‐direction differ, according to two different compositions and two different symmetries.     

Gas-chromatographic analysis of carbides in aluminium and magnesium

Summary A quantitative gas-chromatographic method (molecular sieve column, FID) for the determination of Al₄C₃ in aluminium and magnesium has been developed. The effect of methane from external sources has been investigated and eliminated. Metallographic analysis of carbides in polished specimens were consistent with the gas-chromatographic measurements within a factor of 2. The discrepancy can be explained by the large uncertainties in light microscopy analysis of the small carbides. Analysis of commercial magnesium shows that the metal contains ca. 2–9 ppm of Al₄C₃. The concentration of carbides in aluminium from the electrolysis cell is in the range of 10–35 ppm and in the final product of ca. 2–12 ppm Al₄C₃. CaC₂ has been detected in a few magnesium and aluminium samples by means of gas-chromatography and microprobe analysis.

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Gas-chromatographische Analyse von Carbiden in Aluminium und Magnesium

Zusammenfassung Zur Bestimmung von Al₄C₃ in Aluminium und Magnesium wurde eine quantitative gas-chromatographische Methode (MolekularsiebSäule, FID) entwickelt. Der Einfluß von Methan aus äußeren Quellen, wurde untersucht und ausgeschaltet. Die metallographischen Untersuchungen von Carbiden an polierten Proben stimmten mit den Ergebnissen der gas-chromatographischen Messungen mit einem Faktor von 2 überein. Der Unterschied kann durch die großen Unsicherheiten bei der lichtmikroskopischen Analyse der kleinen Carbide erklärt werden. Die Analyse des technisch reinen Magnesiums zeigt, daß das Metall ca. 2–9 ppm Al₄C₃ enthält. Die Konzentration von Carbiden in elektrolytisch raffiniertem Aluminium liegt im Bereich 10–35 ppm und im Endprodukt bei ca. 2–12 ppm Al₄C₃. CaC₂ wurde in einigen Magnesium- und Aluminiumproben mit Hilfe von gas-chromatographischen und Mikrosondenuntersuchungen festgestellt.

     

Synthese und Charakterisierung neuer intramolekular stickstoffstabilisierter Organoaluminium‐ und Organogalliumalkoxide

Synthesis and Characterization of New Intramolecularly Nitrogen‐stabilized Organoaluminium‐ and Organogallium Alkoxides The intramolecularly nitrogen stabilized organoaluminium alkoxides [Me₂Al{μ‐O(CH₂)₃NMe₂}]₂ ( 1a ), Me₂AlOC₆H₂(CH₂NMe₂)₃‐2,4,6 ( 2a ), [(S)‐Me₂Al{μ‐OCH₂CH(i‐Pr)NH‐i‐Pr}]₂ ( 3a ) and [(S)‐Me₂Al{μ‐OCH₂CH(i‐Pr)NHCH₂Ph}]₂ ( 4 ) are formed by reacting equimolar amounts of AlMe₃ and Me₂N(CH₂)₃OH, C₆H₂[(CH₂NMe₂)₃‐2,4,6]OH, (S)‐i‐PrNHCH(i‐Pr)CH₂OH, or (S)‐PhCH₂NHCH(i‐Pr)CH₂OH, respectively. An excess of AlMe₃ reacts with Me₂N(CH₂)₂OH, Me₂N(CH₂)₃OH, C₆H₂[(CH₂NMe₂)₃‐2,4,6]OH, and (S)‐i‐PrNHCH(i‐Pr)CH₂OH producing the “pick‐a‐back” complexes [Me₂AlO(CH₂)₂NMe₂](AlMe₃) ( 5 ), [Me₂AlO(CH₂)₃NMe₂](AlMe₃) ( 1b ), [Me₂AlOC₆H₂(CH₂NMe₂)₃‐2,4,6](AlMe₃)₂ ( 2b ), and [(S)‐Me₂AlOCH₂CH(i‐Pr)NH‐i‐Pr](AlMe₃) ( 3b ), respectively. The mixed alkyl‐ or alkenylchloroaluminium alkoxides [Me(Cl)Al{μ‐O(CH₂)₂NMe₂}]₂ ( 6 ) and [{CH₂=C(CH₃)}(Cl)Al{μ‐O(CH₂)₂NMe₂}]₂ ( 8 ) are to obtain from Me₂AlCl and Me₂N(CH₂)₂OH and from [Cl₂Al{μ‐O(CH₂)₂NMe₂}]₂ ( 7 ) and CH₂=C(CH₃)MgBr, respectively. The analogous dimethylgallium alkoxides [Me₂Ga{μ‐O(CH₂)₃NMe₂}]₂ ( 9 ), [(S)‐Me₂Ga{μ‐OCH₂CH(i‐Pr)NH‐i‐Pr}]_n ( 10 ), [(S)‐Me₂Ga{μ‐OCH₂CH(i‐Pr)NHCH₂Ph}]_n ( 11 ), [(S)‐Me₂Ga{μ‐OCH₂CH(i‐Pr)N(Me)CH₂Ph}]_n ( 12 ) and [(S)‐Me₂Ga{μ‐OCH₂(C₄H₇NHCH₂Ph)}]_n ( 13 ) result from the equimolar reactions of GaMe₃ with the corresponding alcohols. The new compounds were characterized by elemental analyses, ¹H‐, ¹³C‐ and ²⁷Al‐NMR spectroscopy, and mass spectrometry. Additionally, the structures of 1a , 1b , 2a , 2b , 3a , 5 , 6 and 8 were determined by single crystal X‐ray diffraction.     

Interferences in the determination of aluminium by means of atomic absorption spectrophotometry

Summary The following substances have been investigated with regard to their interfering effect in the determination of aluminium by atomic absorption spectrophotometry: HCl, H₂SO₄, HNO₃, H₃PO₄, alkali and alkaline earth metals, Cu, Fe, Zn, Ni, Mn, Co, Mo, Ti, Cr, V, Si. Ternary systems with La have been examined also. Si exerts a strong depressive effect, whereas other elements in certain concentration ranges exhibit positive effects.

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Störungen bei der atomabsorptionsspektralphotometrischen Bestimmung von Aluminium

Zusammenfassung Folgende Substanzen wurden hinsichtlich einer möglichen Beeinflussung der Aluminiumbestimmung untersucht: HCl, H₂SO₄, HNO₃, H₃PO₄, Alkalimetalle, Erdalkalimetalle, Cu, Fe, Zn, Ni, Mn, Co, Mo, Ti, Cr, V, Si. Ternäre Systeme mit La wurden ebenfalls geprüft. Si übt eine stark depressive Wirkung aus, während andere Elemente in bestimmten Konzentrationsbereichen positiv wirken.

Lecture given on the 2nd Czechoslovak Conference on Flame Speotroscopy, Zvíkov, June 5–8, 1973.     

Synthese und Kristallstrukturen der Phosphaniminato-Komplexe [MCl2(NPPh3)]2 mit M = Al und Ga, [SbCl2(NPMe3)(DMF)]2 sowie des Phosphanimin-Komplexes [Ph3PNH · BF3] · THF

Syntheses and Crystal Structures of the Phosphorane Iminato Complexes [MCl₂(NPPh₃)]₂ with M = Al and Ga, [SbCl₂(NPMe₃)(DMF)]₂, and of the Phosphorane Imine Complex [Ph₃PNH · BF₃] · THF The phosphorane iminato complexes [MCl₂(NPPh₃)]₂ with M = Al and Ga and [SbCl₂(NPMe₃)(DMF)]₂ are formed as colourless crystals by reactions of the anhydrous trichlorides MCl₃ (M = Al, Ga, Sb) with the corresponding silylated phosphorane imines Me₃SiNPR₃ in acetonitrile and in dimethyl formamide, respectively. The phosphorane imine derivative [Ph₃PNH · BF₃] · THF is formed from Me₃SiNPPh₃ and boron trifluoride etherate in boiling tetrahydrofuran. The compounds are characterized by their i. r. spectra and by crystal structure analyses. [AlCl₂(NPPh₃)]₂ : Space group P1 , Z = 1, structure solution with 1 585 observed unique reflections, R = 0.061. Lattice dimensions at ?70°C: a = 917.6, b = 1 053.5, c = 1 145.2 pm, α = 111.72°, β = 100.80°, γ = 109.95°. [GaCl₂(NPPh₃)]₂ : Space group P1 , Z = 1, structure solution with 2 586 observed unique reflections, R = 0.066. Lattice dimensions at ?70°C: a = 917.5, b = 1 058.3, c = 1 153.7 pm, α = 105.52°, β = 107.75°, γ = 109.88°. In both compounds the metal atoms are linked to planar M₂N₂ four-membered rings via the N-atoms of the phosphorane iminato groups. [SbCl₂(NPMe₃)(DMF)]₂ : Space group P2₁/n, Z = 4, structure solution with 3 805 observed unique reflections, R = 0.038. Lattice dimensions at ?70°C: a = 1 913.0, b = 726.8, c = 2 040.7 pm, β = 113.62°. The unit cell contains two symmetry independent dimeric molecules, in which the antimony atoms are centrosymmetricly μ₂ linked via the N-atoms of the phosphorane iminato groups. Along with the oxygen atom of the dimethyl formamide molecule the Sb atoms achieve a ψ-octahedral environment. [Ph₃PNH · BF₃] · THF : Space group C2/c, Z = 8, structure solution with 2 048 observed unique reflections, R = 0.058. Lattice dimensions at ?70°C: a = 2 460.4, b = 869.2, c = 1 978.0 pm, β = 116.35°.     

Aluminium fractionation using cation exchange: comparison of results obtained after fractionation in the field and in the laboratory

Dissolved aluminium was fractionated in the field and the laboratory using a cation-exchange method. Although absolute differences between results obtained from field and laboratory fractionations were generally small, relative differences, expressed as the ratio between labile aluminium determined after laboratory fractionation (Al_ll) and that obtained after field fractionation (Al_lf) could be large. The differences found were not statistically significant, although this may simply reflect the spread in the results. Al_ll/Al_lf had no apparent relationship with the temperature difference between the field and the lab. Although some significant correlations were found between Al_ll/Al_lf and H⁺, no significant correlations were found with the equivalent relative difference in {H⁺} between the lab and the field; nor was any significant correlation found with dissolved organic carbon.