The composition of the evolved gases from the thermal decomposition of certain metal sulfates

By the use of TG—MS, the thermal dissociation of anhydrous CuSO₄ and Al₂(S0₄)₃ was found to proceed according to the reactions:

followed by the reactions:

No SO₃ was indicated in the dissociation of alunite. The sulfate ion appears to dissociate by at least two different mechanisms although the parameter which controls the mechanisms has not been elucidated.     

Pfropfcopolymerisation von Cellulose mit zwei Vinylmonomeren

Zusammenfassung Die vorliegende Arbeit stellt eine Beschreibung von Experimenten dar, die die Erhöhung der Pfropfbereitschaft von trägen Komponenten durch Beimischung von aktiveren zum Ziele hatten.Das Trägermolekül war in allen Fällen Cellulose in Form von hochgradig gereinigtem Zellstoff. Durch die Verwendung von Mischsystemen aus Styrol und Methylmethacrylat gelang es, das trägere Styrol in bedeutend größerer Menge auf die Cellulose aufzupfropfen, als es bei Abwesenheit des aktiven Methylmethacrylats der Fall war.

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Grafting Polymerization of Cellulose with Two Vinyl Monomers

This paper describes experiments to increase the grafting of cellulose with components of poor reactivity by mixing them with highly reactive ones. A highly purified wood pulp was used as backbone. Using combinations of styrene and methyl methacrylate it was possible to graft considerably higher amounts of the poorly reacting styrene than in the absence of the highly reactive methyl methacrylate.

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Nach einem Vortrag, den der erstgenannte der Autoren im Rahmen der Arbeitstagung des Vereins Österreichischer Chemiker am 27. September 1968 in Wien gehalten hat.     

Evaluation of methods to measure differential 15N labeling of soil and root N pools for studies of root exudation

To study patterns of root exudation, the effectiveness of different techniques for in situ 15N labeling of Brassica napus, Centaurea jacea and Lolium perenne with ammonium nitrate was tested. Stem infiltration was found to effectively label plants with thicker stems, whereas, for grass species, cutting and immersing the leaf tips into 15N solution proved to be most effective. A microdiffusion technique to isolate ammonium, combined with conventional cation-exchange chromatography to separate nitrate from amino-N compounds thereafter, was found suitable for separation of the N fractions of plant and soil extracts for 15N determination. All three species were then cultivated in nutrient solution and labeled with 15NH4 15NO3 by stem feeding for 42 hours. Kinetics of 15N labeling of bulk roots and shoots as well as hot water extractable material were assessed, and up to 1.1 at% 15N excess (APE) was found in nutrient solutions. The main amino acids exuded by L. perenne were glycine, serine, alanine and aspartic acid. To assess the suitability of this set of methods to study root exudation in field settings, L. perenne was grown without fertiliser addition in pots containing low-nutrient soil. Plants were 15N labeled via tip immersion and 15N and N concentrations were analysed in shoots, roots and soils during a 48-h interval. Shoots reached 1.25 APE, roots and soil 0.10 and 0.005 APE, respectively. Between 4% (48 h) and 6% (24 h) of total plant 15N was exuded by roots into the soil. In roots amino acids comprised the largest proportion of the soluble 15N pool, whereas soil 15N levels were similar for amino acids and ammonium, exceeding those of nitrate. Mechanisms for the shift within N fractions from roots to soils are briefly discussed.     

Reactions of Silver (I) salts in potassium halide matrices: A differential scanning calorimetry study

Reactions of AgCl, AgSO₄, and Ag₂CO₃ in and with pressed KCl, KBr, and KI disks as well as those of unpressed mixtures were followed by TG and DSC. Except for Ag₂CO₃ and Ag₂SO₄ in KI, the curves obtained were readily interpreted in terms of eutectic melting, decomposition, and complex formation.     

A Nonlinear Dirichlet Problem on the Unit Ball

In the present paper, we consider the nonlinear Dirichlet problem - Δu(x) u^β(x) = 0 is the unit ball and q is a continuous radially symmetric function on B which may be singular on ?B. We state some mild conditions for the function q so that the Dirichlet problem has a positive classical solution.     

Der “thermo-stat” — eine ergänzung der verfahren zur bestimmung katalytisch wirksamer substanzen

The “Thermo-Stat” — a new device for the determination of catalyticaily active substancesA device for the determination of catalytically active substances, called a “ThermoStat”, is described. An additional heater is used to keep constant an arbitrarily preset temperature gradient between the reaction mixture and a cooling coil. Any heat produced by the catalysed reaction induces a deviation from the preset parameter and thus cuts out the additional heater. These breaks are plotted versus time by an integrating recorder. The slope of the reaction curve obtained is a measure of the concentration of the catalyst. As examples, determinations of copper in the range 0.1–2.0μg and molybdenum in the range 5–50 μg are discussed.     

New improvements in oligonucleotide synthesis by use of the p-nitrophenylethyl phosphate blocking group and its deprotection by DBU or DBN

Phosphate protection in the phosphotriester approach is improved by the new, versatile p-nitrophenylethyl group due to its stability in the condensation step and its clean removal by DBU and DBN respectively.     

An Alternative to Automatic Titration

Automatic titrators are designed to do exactly what a lab-technician used to do. Much more sophisticated automation of volumetry is possible. Omegaphoresis [3] in buffer-free [2] sample solutions automatically creates a stationary multiple component titration curve or zoned pattern with normalized concentrations of each separated species. An automatic measurement of each zone length yields their quantity. Simultaneous automatic detection of all the zones in a 10–20 component solution in less than 2 minutes, with a precision of ±2%, a required amount of the order of less than one nanomol and a resolution of ±pK < 0.01 replaces acid-base, complexometric, and certain types of redox-titrimetry. An option of the method allows identification of the components as well.