Haloaldehyde polymers. IX. Polybromodichloroacetaldehyde

Bromodichloroacetaldehyde was synthesized by two methods. The first synthesis started from chloral, which was allowed to react with Ph₃P and the resultant compound brominated and hydrolyzed to give bromodichloroacetaldehyde in an overall yield of 60%. Purification by repeated distillation from P₂O₅ gave polymerization grade bromodichloroacetabldehyde. Bromodichloroacetaldehyde could also be synthesized by bromination of dichloroacetaldehyde diethyl acetal. The yields of this synthesis were only 20–30%, and the aldehyde could not be purified readily to give polymerization grade monomer. Bromodichloroacetaldehyde could be homopolymerized at ?30°C with anionic and also some cationic initiators to a polymer which was insoluble and did not melt but degraded to monomer above 200°C. The ceiling temperature of the polymerization was ?15°C in 1M solution. Bromodichloroacetaldehyde could also be copolymerized with isocyanates, primarily aryl isocyanates, and also with chloral.     

Über die Alkaloide der Granatapfelbaumrinde. IV

Zusammenfassung Die früheren Befunde über den Gehalt an Isopelletierin in der Granatapfelbaumrinde wurden an 5 weiteren Rindenproben bestätigt. Isopelletierin wurde zu 30 bis 40% in den Gesamtalkaloiden aufgefunden.Versuche zeigen, daß das opt.-akt. Methylisopelletierin in schwach alkalischer Lösung bei 20° wohl racemisiert, aber nicht zersetzt wird.I.:F. Galinovsky undO. Vogl, Mh. Chem.83, 1055 (1952). b) II.:F. Galinovsky, G. Bianchetti undO. Vogl, Mh. Chem.84, 1221 (1953). c) III.:F. Galinovsky undF. Höllinger, Mh. Chem.85, 1012 (1954).     

Functional polymers. II. Preparation and polymerization of methyl 5-vinylsalicylate,methyl 5-vinylacetylsalicylate, 5-vinylsalicylic acid,and 5-vinylacetylsalicylic acid

Four new derivatives of 5-vinylsalicylic acid were prepared and their homopolymerization and copolymerization with acrylic acid and methacrylic acid investigated. Methyl 5-vinylsalicylate was prepared in a six-step synthesis from methyl salicylate in an overall yield of 35%. Acetylation in the last step yielded methyl 5-vinylacetylsalicylate. Hydrolysis of methyl 5-vinylsalicylate gave 5-vinylsalicylic acid which was acetylated to 5-vinylacetylsalicylic acid (5-vinyl aspirin). The 5-vinyl-substituted salicylic acid derivatives could be readily homopolymerized and copolymerized with acrylic acid and methacrylic acid to give various compositions of copolymers. It is worth noting that even the monomers with free phenol groups could be readily polymerized with azobisisobutyronitrile as radical initiator to high molecular weight polymers without interference of the phenolic OH group.     

Halogenaldehyd-Polymere. 8. Mitt. Darstellung und Polymerisation von Dichlorfluoracetaldehyd

Ohne Zusammenfassung     

Functional polymers,XL. Syntheses of mono- and di(4-methoxy)benzotriazolesubstituted 2,4-dihydroxyaceto(or benzo)phenones

Eight benzotriazoles and (4-methoxy)benzotriazoles, mono- or di-substituted derivatives of 2,4-dihydroxyaceto(or benzo)phenone were synthesized by azo coupling of (4-methoxy)2-nitrobenzenediazonium chloride with 2,4-dihydroxyaceto(or benzo)phenone followed by reductive cyclization. Pure mono-substituted compounds were very difficult to prepare. Careful selection of thepH for the azo coupling and selection of the proper reagents for the reductive cyclization were essential. All compounds were characterized by their ultraviolet, infrared¹H and¹³C NMR spectra and their elemental analysis. These compounds have both the 2(2-hydroxyphenyl)2H-benzotriazole unit and a 2-hydroxyaceto(or benzo)phenone unit in the same molecule and are effective and useful ultraviolet absorbers.Dedicated to Prof. Dr.K. Komarek, Vienna, on the occasion of his 60^th birthday with best wishes.     

Comparative performance study of ICP mass spectrometers by means of U “isotopic measurements”

The performance of four commercially available ICPMS instruments of three different types was compared by means of uranium “isotopic measurements”. Examined were two quadrupole sector (different generation, different manufacturer), one single detector double focusing magnetic sector and one multiple collector double focusing magnetic sector instruments. The same samples of the IRMM-072 series were used under routine conditions to measure the ²³³U/²³⁵U and the ²³³U/²³⁸U ratios which, in these samples, vary over almost three orders of magnitude from ～ 1 to ～ 2 · 10^–3. Within expanded (k = 2) uncertainties, good agreement was observed between the certified values and the data internally corrected for mass-discrimination effects. The magnitude of the evaluated uncertainties was different for each type of instrument. With the multiple collector instrument, expanded uncertainties varied from ± 0.04% to± 0.24% for the ²³³U/²³⁵U ratio, and from ± 0.08% to ± 0.27% for the ²³³U/²³⁸U ratio. They were ～ 1 to 5 times larger with the single detector magnetic sector instrument, and ～ 10 to 25 times larger with both quadrupole sector instruments. With the multiple collector instrument, repeatability of the measurements seemed to be limited by the difficulty of correcting properly for instrumental background, whereas with the single detector magnetic sector instrument the counting statistics was the only limitation (on smallest ratios). Apparent mass-discrimination was clearly found to be larger but more reproducible (and hence easier to correct for) in the case of magnetic sector instruments than for both quadrupole sector instruments. If space charge effects were the main source of mass-discrimination for all instruments, these results are in contradiction with the hypothesis of the size of mass-discrimination decreasing with the acceleration voltage. With the single detector magnetic sector instrument in particular (when operated by changing the ion energy only), our results pointed at more than only one major source of mass-discrimination, with variable size depending on the ratios measured.     

Solid-state,optical-rotation measurements on macromolecules using powder-suspensions

Summary We report techniques for measuring optical rotation of suspended solids, including dissymmetric molecular crystals (e.g. sodium chlorate and bromate), synthetic polymers, polypeptides and biopolymers. Examples include poly(triphenylmethyl methacrylate), poly-S-lactide, poly-L-hydroxyproline, hemocyanine, cellulose acetate andRNA. The results indicate that optical rotation measurements are sensitive to differences in secondary structure and can serve as a probe for structural differences between solid-state and solution.

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Messung der optischen Rotation von Makromolekülen im Festzustand unter Verwendung von Pulversuspensionen

Zusammenfassung Es wird über eine Methode zur Messung der optischen Rotation von Festkörpern in Suspensionen berichtet, wobei dissymetrische Kristalle (z. B. Natriumchlorat und -bromat), synthetische Polymere, Polypeptide und Biopolymere behandelt werden. Die Beispiele umfassen Poly(triphenylmethylmethacrylat), Poly-S-lactid, Poly-L-hydroxyprolin, Hemocyanin, Celluloseacetat undRNA. Die Ergebnisse zeigen, daß die optischen Rotationen bezüglich Unterschiede in der Sekundärstruktur empfindlich sind und daß diese Messungen als ein Maß für Strukturunterschiede zwischen Festzustand und Lösung herangezogen werden können.

     

Functional Polymers. X. Hydrolysis Studies of Polyesters and Polycarbonates of Bithionol and Their Copolymers

The hydrolysis behavior of a number of polymers of bithionol [2,2′-thiobis(4,6-dichlorphenol)] was investigated. The hydrolysis of polyesters of bithionol with aliphatic or aromatic dicarboxylic acids or phosphorus acids as well as polycarbonates and alternating copolycarbonates and polyurethanes or co(po1y-carbonates/polyurethanes) depends primarily on the water solubility of the polymer or at least on its degree of swelling. In the most favorable case of the alternating bithionol/PEG 4000 co-polycarbonate the hydrolysis rate of the polymer at 37°C was 1.62 L/mol/min at pH 10, 0.63 L/mol/min at pH 4 and 0.17 L/mol/min at pH 7.4. Copolycarbonates and copolyurethanes with PEG 4000 in the polymer chain have slightly lower rates of hydrolysis. When the solubility of the polymer is low and the crystallinity