Damped concentration oscillations in the oxidation of the reduced forms of heteropolyacids

Concentration oscillations of reduced forms of phosphorus-molybdenum, silicon-molybdenum, and silicon-tungsten heteropolyacids of the 12th row have been induced by the pulse radiolysis of their 5×10^–2M aqueous solutions. Appearance of these oscillations seems to be related to the reaction of reduced forms of heteropolyacids with hydrogen peroxide which is also produced during water radiolysis.

---

-, 12- , 5·10^–2M . , -, - , .

     

Experimental study of the bifurcation diagram in the Belousov-Zhabotinskii reaction

In the citric acid-Mn²⁺–H₂SO₄–KBrO₃ system a hysteresis phenomenon in the switching on and off of the oscillations has been observed. The possible bifurcation diagrams of the system are discussed.

---

-Mn⁺²–H₂SO₄–KBrO₃ . .

     

Effect of discontinuous irradiation in the radiolysis of heavy metal azides

A decrease in the steady-state rate of radiation gas evolution from silver and thallium azides under discontinuous irradiation has been revealed and the critical time for the darkening period (0.1 s) has been determined. This effect is not observed for lead and cadmium azides. An interpretation for the effect of discontinuous irradiation is suggested.

---

. ( .І ). . .

     

Springer in the International Year of Chemistry 2011

Announcement

Springer in the International Year of Chemistry 2011     

The role of adsorption calorimetry in the study of surface phenomena

After a short survey of the development of adsorption calorimetry, the current position of this method is demonstrated in the light of some more recent results. A critical analysis is made of the areas in which adsorption calorimetry could be successfully applied in the future, either alone or, preferably, in combination with other techniques.

---

Zusammenfassung Nach einem kurzen Überblick über die Entwicklung der Adsorptionskalorimetrie wird die augenblickliche Bedeutung dieser Methode an Hand einiger neuerer Ergebnisse demonstriert. Es wird kritisch analysiert, in welchen Gebieten die Adsorptionskalorimetrie in Zukunft erfolgreich eingesetzt werden kann, sei es allein, oder zweckmäßigerweise in Verbindung mit anderen Techniken.

---

Résumé Après une brève revue du développement de la calorimétrie d'adsorption, on montre la position actuelle de cette méthode à la lumière de quelques résultats plus récents. On donne une analyse critique des domaines dans lesquels la calorimétrie d'adsorption pourraît être appliquée avec succès, seule ou, de préférence, en combinaison avec d'autres techniques.

---

. , , / .

     

The situation with the INTAS projects in the field of chemistry

Information

The situation with the INTAS projects in the field of chemistry     

Participation of molecular oxygen in the formation of complete oxidation products via a concerted mechanism

A comparison is given between the rate of catalytic reactions and that of decomposition of surface compounds under the influence of molecular oxygen of different isotopic composition in reactions of complete oxidation of n-butane and 1-hexene on zinc oxide and cuprous oxide. It has been shown that the rates of accumulation of products containing heavy oxygen are much smaller than those theoretically expected from the heavy isotope concentration in molecular oxygen. A conclusion is drawn that molecular oxygen is not directly incorporated into the reaction products but promotes decomposition of the surface compounds by oxidizing the surface sites where these compounds are stabilized.

---

- 1- . , , , , . , , , , .

     

Springer in the International Year of Chemistry 2011

Announcement

Springer in the International Year of Chemistry 2011     

Springer in the International Year of Chemistry 2011

Announcement

Springer in the International Year of Chemistry 2011     

Springer in the international year of chemistry 2011

Announcement

Springer in the international year of chemistry 2011     

Springer in the International Year of Chemistry 2011

News and Announcements

Springer in the International Year of Chemistry 2011     

Oxidation of organic sulfides and sulfoxides by oxygen in the presence of copper complexes

In liquid-phase oxidation of sulfides and sulfoxides by air oxygen in acetone solution a high catalytic activity is shown by copper(II) phenolates containing electrodonor substituents in their benzene ring. Reactivity of aliphatic sulfides with R=C₁–C₅ in sulfoxide formation is 5–10 times higher than that of petroleum sulfides. Oxidation rate of sulfides to sulfoxides is by an order of magnitude higher than that of sulfoxides to sulfones.

---

(II), - . R=C₁–C₅ 5–10 , . .

     

Effect of Sn addition on the catalytic properties of the metallic phase in Pt?Sn/Al2O3 catalysts

Platinum-tin/alumina supported catalysts have been studied. The TPR results show an assisted reduction of tin by platinum. The effect of alloying in cyclohexane dehydrogenation, o-xylene hydrogenation and cyclopentane hydrogenolysis is discussed.

---

- , . . , - .

     

Kinetics of reactions in solution: Method for the treatment of data from non-isothermal chemical kinetic experiments

A new method is proposed for the treatment of kinetic data derived from non-isothermal kinetic experiments for the determination of the parameters of the Arrhenius equation. The results obtained from its application show the excellent precision of this method.

---

. , , .

     

Graduation ceremony at JRC-IRMM of the first graduates of the Euromaster Measurement Science in Chemistry

News and Announcements

Graduation ceremony at JRC-IRMM of the first graduates of the Euromaster Measurement Science in Chemistry     

Identification of the major diacylglycerol acyltransferase mRNA in mouse adipocytes and macrophages

Background

Triacylglycerols (TAGs) are the major form of energy storage in eukaryotes. Diacylglycerol acyltransferases (DGATs) catalyze the final and rate-limiting step of TAG biosynthesis. Mammalian DGATs are classified into DGAT1 and DGAT2 subfamilies. It was unclear which DGAT was the major isoform expressed in animal cells. The objective was to identify the major DGAT mRNA expressed in cultured mouse adipocytes and macrophages and compared it to that expressed in tung tree seeds.

Methods

qPCR evaluated DGAT mRNA levels in mouse 3?T3-L1 adipocytes and RAW264.7 macrophages and tung tree seeds.

Results

TaqMan qPCR showed that DGAT2 mRNA levels were 10–30 fold higher than DGAT1 in adipocytes and macrophages, and DGAT mRNA levels in adipocytes were 50–100-fold higher than those in macrophages. In contrast, the anti-inflammatory tristetraprolin/zinc finger protein 36 (TTP/ZFP36) mRNA levels were 2–4-fold higher in macrophages than those in adipocytes and similar to DGAT1 in adipocytes but 100-fold higher than DGAT1 in macrophages. SYBR Green qPCR analyses confirmed TaqMan qPCR results. DGAT2 mRNA as the major DGAT mRNA in the mouse cells was similar to that in tung tree seeds where DGAT2 mRNA levels were 10–20-fold higher than DGAT1 or DGAT3.

Conclusion

The results demonstrated that DGAT2 mRNA was the major form of DGAT mRNA expressed in mouse adipocytes and macrophages and tung tree seeds.

     

Intermediates in the interaction of 1-butene and butadiene with an iron-antimony oxide catalyst

A temperature programmed desorption study of the intermediates in the interaction of 1-butene and butadiene with an iron-antimony oxide catalyst is reported.

---

-І .

     

The structure of the products of the interaction of benzoxazolone derivatives with α, β-dichloropropionyl chloride in the presence of triethylamine

It has been shown that the products of the reaction of benzoxazolone (I) and 6-chlorobenzoxazolone (II) with , -dichloropropionyl chloride in the presence of triethylamine are, respectively, 3-[-(N-benzoxazolonyl)--chloropropionyl] benzoxazolone and 3-[-(N-6-chlorobenzoxazolonyl)--chloropropionyl]-6-chlorobenzoxazolone. A possible explanation of the fact that in the reaction of I and II in the presence of triethylamine only the chlorine atom in the -position of derivatives of , -dichloropropionic acid takes part, is that the chlorine in the -position is deactivated through enolization.     

Radon in the environment A current bibliography

Biography

Radon in the environment A current bibliography