A chemical study ofPlectranthus glaucocalyx Maxim.

Summary A previously unknown crystalline substance C₂₀H₂₈O₄, calledplectrin, has been isolated from the leaves ofPlectranthus glaucocalyx Maxim., family Labiatae.Khimiya Prirodnykh Soedinenii, Vol. 1, No. 6, pp. 427–428, 1965     

A study of the reactions of the chemical modification of chymotrypsin. I

Summary The reaction of chymotrypsin with a number of modified analogs of the specific inhibitor of chymotrypsin L-1-tosylamido-2-phenylethyl chloromethyl ketone has been studied; the compounds investigated were D-1-tosylamido-2-phenethyl chloromethyl ketone, phenethyl chloromethyl ketone (PECK), and benzylethyl chloromethyl ketone (BCMK).It has been shown that D-TAPK does not possess inhibiting activity. The inhibiting capacity of PECK is considerably reduced. A simultaneous decrease in the length of the carbon chain and the elimination of the tosylamino group (BCMK) practically destroys the inhibiting action of the reagent.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 2, pp. 116–120, 1968     

Free-radical addition reactions initiated by metal oxides, VI

CuO catalyzed additions of ethyl cyanoacetate, initiated thermally and by di-tert-butyl peroxide, to 1-decene and ethyl 10-undecylenoate were investigated. The CuO catalyzed reaction proceeds already at 80°C at a high rate, produces 11 adducts in high yields and represents the first example of catalysis in radical addition reactions of non-halogenated compounds.

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1- 10-, CuO, -.-. , CuO, 80°C, 11 . .

     

Influence of solvent on platinum catalyst formation

The adsorption properties of Pt-black reduced in various solvents (water, sulfuric acid, ethanol, alkali, heptane) have been studied. The nature of solvent is shown to influence the catalyst surface formation, the heat of hydrogen adsorption and the ratio of its forms.

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Pt-, : , , , , . , , .

     

The effect of preparation conditions on the activity and stability of copreciptitated Ni/Al2O3 catalysts for the methanation of carbon monoxide

The activities and stabilities of coprecipitated Ni/Al₂O₃ methanation catalysts depend markedly on their preparation and pretreatment. The results are discussed in relation to the structure of the precipitate and to changes which occur during calcination and reduction.

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Ni/Al₂O₃ . , .

     

Transient phenomena in o-xylene oxidation in a fluidized bed reactor

The effect of stirring a vanadium-titanium-tellurium catalyst on the yield of the selective oxidation products for oxidation of o-xylene in fluidized bed reactors has been studied. It is shown that the stirring of catalyst pellets increases the yield of phthalic anhydride.

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-- - . , .

     

The structure of karatavic acid

Conclusions Karatavic acid has been isolated from the resin of the roots ofFerula karatavica Rgl. et Schmalh; this is an ether of umbelliferone and a hydroxy acid C₁₅H₂₄O₃ probably having the humulane type of hydrocarbon skeleton. Two possible structural formulas—(I) and (II)—have been proposed for karatavic acid.Khimiya Prirodnykh Soedinenii, Vol. 4, No. 5, pp. 283–287, 1968     

Spectrographic estimation of Ga, In and Tl in semiconductor grade selenium

Summary An emission spectrographic method for the estimation of Ga, In and Tl in semiconductor grade selenium at less than a ppm concentration has been developed. The impurities were separated from 1 g of selenium by volatilizing it from its solution in nitric acid and sulphuric acid. The residue containing the impurities was dissolved in small amounts of 6 M HCl and was loaded along with the washings on 10 mg mixture containing graphite (90%) and sodium chloride carrier (10%) in the electrode crater. The spectra were excited in a d.c. arc carrying 13 A current. The detection limits lie in the range of 0.0025–0.005 ppm. The precision of the method ranges from 7–12% for these elements. The recoveries of impurities from selenium were confirmed using radioactive tracers.

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Spektrographische Bestimmung von Gallium, Indium und Thallium in Halbleiterselen

Zusammenfassung Eine 1 g-Probe wird in Salpeter- und Schwefelsäure gelöst und die Verunreinigungen durch Verflüchtigung des Selens isoliert. Sie werden in 6 M HCl gelöst und zusammen mit einem Graphit/NaCl-Gemisch (91) in die Elektrode eingebracht. Zur Anregung dient ein Gleichstrombogen (13 A). Die Nachweisgrenzen liegen im Bereich von 0.0025–0.005 ppm, der Variationskoeffizient bei 7–12%. Die Wiedergewinnung der Verunreinigungen wurde mit Hilfe von Radioindicatoren geprüft.

     

Quinolinic acid as a reagent for the gravimetric and volumetric estimation of palladium

Summary Like -amino-picolinic acid, quinolinic acid behaves as a highly selective reagent for palladium with which it forms a complex of composition Pd(C₇H₄O₄N)₂. The complex being very stable is precipitated from solutions with an acidity of 0.25 N to a maximum p_H of 2.1 and thus is separated from all the common ions and other platinum metals except copper which, however, can be kept in solution in presence of EDTA. The palladium complex is either weighed after drying or dissolved in a standard potassium cyanide solution which is later back titrated with silver nitrate solution.     

A twin optically-pumped far-infrared CH3OH laser for plasma diagnostics

A twin optically-pumped far-infrared CH₃OH laser has been constructed for use in plasma diagnostics. The antisymmetric doublet due to the Raman-type resonant two-photon transition is reproducibly observed at 118.8 m. With the 118.8-m line, it is obtained from the frequency separation of the anti-symmetric doublet that CH₃OH absorption line center is 16±1 MHz higher than the pump 9.7-m P(36) CO₂ laser line center. It is shown that the Raman-type resonant two-photon transition is useful in order to get several-MHz phase modulation for the far-infrared laser interferometer. Some preliminary performances of this twin laser for the modulated interferometer are described.This work was carried out under the collaborating research program at the Institute of Plasma Physics, Nagoya University, Nagoya 464, Japan.