Wyniki wyszukiwania - Biblioteka Nauki

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Particular Features of Formation of the Anhydrous Solid Solutions of Mg, Mn(II), Co(II) and Zn Diphosphates

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Antraptseva N. , Tkachova N. , Ponomaryeva I.

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2006

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tom Vol. 80, nr 10

1623-1631

EN

The sequence of physical and chemical as well as structural transformations accompanying the formation of solid solutions of anhydrous Mg,Mn(II), Co(II) and Zn diphosphates by thermal dehydration of corresponding hydrated salts was investigated. The interconnection between state of water in crystallohydrate, on one side, and mechanism of its removal, on the other side, was considered. The peculiarities controlling the processes of formation of solid solutions of anhydrous divalent metal diphosphateswere established.

2

The thermolysis of aryl desyl ethers. Formation of furan derivatives

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Gaber A. E.-A. M.

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1998

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tom Vol. 46, No. 2

185-193

EN

Thermal reactions of aryl desyl ethers PhCOCH(OAr)Ph (Ar = Ph, p-tolyl) 1, 2 gave 2,3-diphenylbenzo(b)furan 5a,b and phenols as major products in addition to small amounts of toluene, benzil, benzoic acid, benzophenone, arylbenzoate, p-benzylphenol, 2,3,4,5-tetraphenylfuran 4 and 2,3-diphenylbenzo (l,4) dioxin 6a,b. In the presence of isoquinoline as a radical trap, 1 gave 1-phenylisoquinoline beside the previous products. Analogous results, in addition to diphenylmethane and benzophenone as major products as well as 1,1,2,2-tetraphenyl ethane and dibenzhydryl ether as minor products, were also obtained on heating the benzhydryl desyl ether 3. A free radical mechanism has been postulated to take place through the initial homolysis of the C-OAr bond to account for the identified products.

3

Zastosowanie spektroskopii EPR do badania wolnych rodników generowanych termicznie w drotawerynie

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Ramos P. , Pilawa B. , Adamski M.

Annales Academiae Medicae Silesiensis

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2014

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tom 68

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nr 1

28-37

EN

INTRODUCTION Microorganisms should be removed from drugs during their production, however, sterilization processes should not produce free radicals. Free radicals in drotaverine were studied. The applicability of thermal sterilization for drotaverine was investigated. MATERIAL AND METHODS Drotaverine heated to 160oC was examined by the EPR method. Free radical concentration, their distribution in the sample, the complex character of the free radical system and magnetic spin-spin interactions in the drug were determined. Changes in the free radical concentration in drotaverine during storage after sterilization also were examined. The sterilization conditions were chosen according to pharmakopeal norms. The analysed drug was sterilized in dry hot air. RESULTS EPR lines were not obtained for drotaverine before sterilization. It was demonstrated that drotaverine after thermal sterilization at temperature 160oC contains free radicals and exhibits EPR spectra. The free radical concen-tration in drotaverine changes with storage time after thermal treatment. Interactions with oxygen are probably responsible for this effect. The free radicals are homogeneously distributed in drotaverine since characteristic correlations between the amplitudes and linewidths of the EPR lines and microwave power were observed. The free radicals are closely located to one another in drotaverine and they strongly interact in a dipolar manner, which cause broadening of the EPR spectra. Continuous microwave saturation of the EPR spectra revealed that slow spin-lattice relaxation processes occur in thermally sterilized drotaverine. The shape of the EPR spectra and asymmetry parameters of the test drug change with increasing microwave power, indicating the complex nature of the free radicals in the sample. CONCLUSIONS Drotaverine should not be thermally sterilized because of free radical formation. The obtained results confirmed the usefulness of EPR spectroscopy to examine thermally sterilized drugs. The EPR method may be used as a supplement to microbiological tests.

PL

WSTĘP Leki wymagają usunięcia drobnoustrojów podczas ich produkcji, jednak procesy sterylizacji nie powinny generować wolnych rodników. Zbadano wolne rodniki w drotawerynie. Sprawdzono, czy sterylizacja termiczna może być w tym przypadku stosowana. MATERIAŁY I METODY Zbadano drotawerynę ogrzewaną w 160oC metodą EPR. Wyznaczono koncentrację wolnych rodników, określono sposób ich rozmieszczenia w ogrzanej próbce, złożoność układu wolnorodnikowego oraz oddziaływania magnetyczne spin-spin. Zbadano również zmiany koncentracji wolnych rodników w drotawerynie podczas przechowywania leku po sterylizacji. Warunki sterylizacji termicznej wybrano zgodnie z obowiązującymi normami farmakopealnymi. Lek sterylizowano suchym gorącym powietrzem. WYNIKI Nie uzyskano linii EPR dla drotaweryny przed sterylizacją. Wykazano, że drotaweryna po sterylizacji termicznej w temp. 160oC zawiera wolne rodniki i wykazuje widma EPR. Koncentracja wolnych rodników w drotawerynie zmienia się wraz z czasem przechowywania leku po obróbce termicznej. Za efekt ten odpowiadają prawdopodobnie oddziaływania z tlenem. Wolne rodniki w drotawerynie rozmieszczone są jednorodnie, ponieważ zaobserwowano charakterystyczne dla tego przypadku zależności amplitudy i szerokości linii EPR od mocy mikrofalowej. Wolne rodniki w drotawerynie są położone blisko siebie i silnie oddziałują dipolowo, co powoduje poszerzenie widm EPR. Ciągłe nasycenie mikrofalowe widm EPR wykazało, że w drotawerynie sterylizowanej termicznie zachodzą wolne procesy relaksacji spin-sieć. Kształt widm EPR i parametry asymetrii testowanego leku zmieniają się wraz ze wzrostem mocy mikrofalowej, co wskazuje na złożony charakter układu wolnych rodników w próbce. WNIOSKI Drotaweryna nie powinna być sterylizowana termicznie ze względu na generowanie wolnych rodników. Uzyskane rezultaty potwierdziły przydatność spektroskopii EPR do badania leków sterylizowanych termicznie. Metoda EPR może być wykorzystana jako uzupełnienie testów mikrobiologicznych.

4

Fullerene like and polyaromatic structures catalysts of initial stages of coal thermolysis into fuels.

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Grigorieva E. N.

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tom Vol. 9, nr 56

395-400

EN

Natural fullerene like and polyaromatic substances and synthetic fullerene C 60 had catalytic in coal treatment. Synthetic fullerene C 60 and shungite carbons from two deposits of Karelia, Russia, accelerated benzyl phenyl ether thermolysis without the process character changing, but they changed tetralin thermolysis: the main reaction was the dehydrogenation teralin into naphthalene. Dehydrogenation led to rapid conversion of COM into defferent aromatic compounds such as naphthalene, phenathrene, benz[a]pirene and so on even at low temperatures. Catalytic ability of shungite carbons in different organic reactions was supposed to be due to its fullerene like structure.

5

Antifriction and antiwear properties of molybdenum sulfides nanosized particles synthesized using nitrogen containing ionic liquids

51%

Parenago O. P. , Kuzmina G. N. , Terekhin V. D. , Basharina K. Y.

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2010

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tom Vol. 45, nr 1

7-14

EN

We have developed the synthesis pathways of molybdenum trisulfide nanoparticles that are soluble in hydrocarbon media and demonstrate their activity as antifrictional and antiwear additives to lubricants. Bis(tetraalkylammonium)tetrathiomolybdates as precursors of molybdenum trisulfide nanoparticles are synthesised by the interaction of ammonium thiomolybdate with tetraalkylammonium halides, including alkyl groups of the various types. The properties of synthesised molybdenum compounds were determined by UV- and IR-spectroscopy and by thermogravimetric analysis. The molybdenum trisulfide nanoparticles were formed by thermolysis of these compounds, and their sizes and size distribution were determined by small angle X-ray spectroscopy. The antifrictional and antiwear activity of molybdenum compounds and MoS3 nanoparticles were evaluated using various types of tribometers.