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1.
A. Grittner J. Szilasi C. R. Alder Wright und C. Thompson 《Fresenius' Journal of Analytical Chemistry》1886,25(1):594-595
Ohne Zusammenfassung 相似文献
2.
Eschweiler-Clarke methylations of both acyclic and cyclic polyamines can lead to methylation products of fragments of the original polyamine; thus 1,5,9,13-tetra-azatridecane yields 1,1,3,3-tetramethylpropanediamine exclusively and 1,5,9-triazacyclododecane gives 45% 1,5,9-trimethyl-1,5,9-triazacyclodecane and 45% 2,6,10-trimethyl-2,6,10-triazaundecane. 相似文献
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A method for the determination of low levels of ammonium ion in solution by optical emission spectrometry with an inductively coupled argon plasma source operated at 27 MHz is presented. The ammonium ion is oxidized with sodium hypobromite in alkaline medium, the evolved nitrogen is passed into the argon plasma, and the NH emission intensity produced in the plasma at 336.0 nm is monitored. A practical detection limit of 0.1 μg N ml-1 for 5-ml aqueous sample solutions has been obtained. The method has been applied to the determination of the exchangeable ammonium content of soil samples. 相似文献
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Gases in the atmosphere are monitored with chemically-coated quartz piezoelectric crystals; the method is demonstrated in the use of polyethylene glycol for toluene diisocyanate determination. A microprocessor is used to control the gas sample flow through the detector head as well as the data acquisition. A computer-based procedure for data treatment permits signal integration and background drift correction, resulting in a theoretical detection limit of about 0.006 ppm. The design of a basic portable instrument for piezoelectric crystal monitoring of toxic gas is described with a view to future modification and microprocessor control. 相似文献
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Dithizone and tri-n-octylphosphine oxide (TOPO) were tested as coatings for quartz piezoelectric crystals to be used in a detector for touene diisocyanate (TDI). Cobalt(II) chloride and polyethylene glycol (PEG) with molecular weights of 400 and 1540 were tested for suitability as coatings for detecting humidity variations so that correction for humidity could be obtained from a two-crystal system. Sensitivities for TDI of 12 and 75 Hz ppm?1 were found with dithizone and TOPO, respectively, between 0 and 1 ppm TDI. Cobalt chloride-coated crystals showed a sensitivity for water of 0.053 Hz ppm?1 at 8000 ppm water and about 40 Hz ppm?1 for TDI at the 2 ppm level. PEG-400 and PEG-1540 provided sensitivities to water of 0.038 and 0.051 Hz ppm?1 respectively, and the response was linear over the range 9000—13 000 ppm water. All coatings showed irreversible behaviour towards TDI. 相似文献
8.
UV.-irradiation (λ ≥ 327 nm) of the α,β-unsaturated γ,δ-epoxy ketone 2 in pentane gives the isomers oxidoketone 3 and diketone 4, in high yield. On treatment with BF3O(C2H5)2, 2 undergoes rearrangement to the diketone 4 and the isomeric lactone 8 and yields also the dimer 9. 相似文献
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Dr. Ulrich F. J. Mayer Elliot Murphy Dr. Mairi F. Haddow Prof. Michael Green Prof. Roger W. Alder Prof. Duncan F. Wass 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(13):4287-4299
We make the case for benzo[c]quinolin‐6‐ylidene ( 1 ) as a strongly electron‐donating carbene ligand. The facile synthesis of 6‐trifluoromethanesulfonylbenzo[c]quinolizinium trifluoromethanesulfonate ( 2 ) gives straightforward access to a useful precursor for oxidative addition to low‐valent metals, to yield the desired carbene complexes. This concept has been achieved in the case of [Mn(benzo[c]quinolin‐6‐ylidene)(CO)5]+ ( 15 ) and [Pd(benzo[c]quinolin‐6‐ylidene)(PPh3)2(L)]2+ L=THF ( 21 ), OTf ( 22 ) or pyridine ( 23 ). Attempts to coordinate to nickel result in coupling products from two carbene precursor fragments. The CO IR‐stretching‐frequency data for the manganese compound suggests benzo[c]quinolin‐6‐ylidene is at least as strong a donor as any heteroatom‐stabilised carbene ligand reported. 相似文献