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1
Content available remote Metody wytwarzania izo-α-kwasów
Dobrzyńska-Inger A., Rój E., Kostrzewa D.
Przemysł Chemiczny
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2014
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T. 93, nr 8
1321-1327
PL
Omówiono rolę chmielu i ekstraktu chmielowego jako głównej przyprawy podczas wytwarzania piwa. Wyjaśniono podstawową reakcję, której ulegają chmielowe α-kwasy w brzeczce warzelnej oraz wpływ tej reakcji na smak piwa. Przedstawiono metody wytwarzania pochodnych α-kwasów poza kotłem warzelnym.
EN
A review, with 50 refs., of chem., thermal and photochem. methods for isomerization of α-acids in hop exts.
2
Content available Hiperwalentne związki siarki, selenu i telluru. Część 4. Selenurany i tellurany
Zając A.
Wiadomości Chemiczne
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2012
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[Z] 66, 11-12
1119-1144
EN
In this part selenuranes (10-Se-4 and 10-Se-5) and perselenuranes 12-Se-6 as well as telluranes 10-Te-4 and pertelluranes 12-Te-6 will be presented. The main goal is to describe recent reports on the synthesis, chemical, physical, spectral and conformational behavior, stereochemistry, stability and biological activity of these compounds. Their occurrence as reaction intermediates will also be shown.
3
Content available Hiperwalentne związki siarki , selenu i telluru. Część 3. Sulfuran Martina , sulfurany 10-S-5 i 12-S-6
Zając A.
Wiadomości Chemiczne
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2012
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[Z] 66, 9-10
893-907
EN
In this part of the review one of the most famous 10-S-4 sulfurane called Martin sulfurane together with sulfuranes 10-S-5 and persulfuranes 12-S-6 will be presented. Martin sulfurane has been well known for a relatively long time but it is still useful in organic synthesis as a dehydrating, coupling and oxidizing agent. Its use in selected substitution reactions will be also described. Next, synthesis and selected properties of sulfuranes 10-S-5, mainly sulfurane oxides, and persulfuranes 12-S-6, will be shown. Besides synthetic methods, the review is focused on the investigations of the stability and isomerization of these types of compounds, which is particularly interesting for persulfuranes, because of the presence of three 3c-4e bonds.
4
Content available Hiperwalentne związki siarki, selenu i telluru. Część 2. Sulfurany 10-S-3 i 10-S-4
Zając A.
Wiadomości Chemiczne
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2012
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[Z] 66, 7-8
593-622
EN
The compounds presented herein are sulfuranes 10-S-3 and 10-S-4 containing hypervalent sulfur atom. They have been known for a relatively long time. Nevertheless, they, and especially 10-S-4 species, are still of great interest due to their unique properties. The review presents recent approaches to the synthesis of these compounds, their selected structural, physical, chemical, stereochemical and electronic properties and their use as reagents and catalysts in several reaction types. The presence of structures of these types as intermediates, which explains selected reaction mechanisms, will also be shown.
5
Content available Hiperwalentne związki siarki, selenu i telluru. Część 1. Charakterystyka ogólna
Zając A.
Wiadomości Chemiczne
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2012
|
[Z] 66, 5-6
529-541
EN
The goal of this four-part review is a presentation of the results of recent studies on the properties and chemistry of hypervalent sulfur, selenium and tellurium compounds. The term “hypervalency” has been known since 1969 when Musher used it to describe molecules bearing heteroatoms which formally did not fulfill the octet rule. This violation was explained by the postulate concerning the existence of a 3-center 4-electron bond between a hypervalent heteroatom and two axial electronegative ligands. The bond is the a combination of two ligand orbitals and a pz orbital of a central heteroatom which results in the formation of three molecular orbitals. The distances between the central atom and these two ligands are longer than the length of the typical sp2 bonds, such as equatorial ones. Moreover, the effective electron density is shifted from the central atom towards the axial ligands what results in the fulfillment of the octet rule of this atom. The geometry of this system is trigonal bipyramid (Fig. 2), except from compounds having three 3-center 4-electron (3c-4e) bonds which have tetragonal bipyramid geometry (Fig. 3). The term “geometry” includes positions of ligands and lone electron pairs. The stability of hypervalent compounds is affected by a few factors: electronegativity of ligands, formation of five-membered cyclic structures involving the central atom and the number of electron shells of the central atom. Martin proposed three-symbol notation N-X-L for these structures, which was further modified (Tab. 1). Hypervalent compounds can isomerize according to various mechanisms: Berry pseudorotation (Scheme 1), turnstile rotation (Scheme 2), cuneal inversion (Scheme 3), lever mechanism (Scheme 4), or Bailar twist (Scheme 5). Furthermore, hypervalent structures of 10-X-4 and 10-X-5 type with trigonal bipyramid geometry, C1 or C2 symmetry and at least three different ligands can exist as optically active species (Tab. 2, Fig. 5–7, Scheme 6), especially the "spiro" ones, which are resistant to isomerization. In 1977 Martin and Balthazor proposed extended Cahn-Ingold-Prelog convention for description of the absolute configuration of chiral hypervalent compounds (Fig. 5).
6
Content available Intensyfikacja wykorzystania ekstraktu chmielowego do produkcji piwa
Skorek U., Hubicki Z., Rój E.
Chemik
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2011
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Vol. 65, nr 3
160-163
PL
Dokonano przeglądu metod intensyfikacji wykorzystania ekstraktów chmielowych poprzez ich izomeryzację. Omówiono dostępne izomery w obrocie handlowym wraz z ich charakterystyką. Przedstawiono Nowe Międzynarodowe Normy do analizy ilościowej zizomeryzowanych a-kwasów metodą chromatografii HPLC .
7
Content available remote Możliwości zagospodarowania odpadów chloroorganicznych
Myszkowski J., Milchert E., Paździoch W., Bartkowiak M., Pełech R.
Wiadomości Chemiczne
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2010
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[Z] 64, 5-6
493-506
EN
Possible ways of utilization of waste chloroorganic compounds have been presented. The methods like isomerization, hydrodechlorination, ammonolysis and chlorolysis have been described. Practical application of these methods allows the management of chloroorganic wastes coming from waste water and waste streams formed e.g. in the production of vinyl chloride by dichloroethane method [2] and in the production of propylene oxide by chlorohydrin method [1]. Four valuable methods of chlorocompounds utilization have been discussed. The first one is isomerization of 1,1,2-trichloroethane [3, 4] to 1,1,1-trichloroethane as the valuable product with a less toxicity than the substrate. The second method is ammonolysis of waste 1,2-dichloropropane and 1,2,3-trichloropropane. Third described method is hydrodechlorination [5, 6] of chloroorganic compounds, especially used for reduction of chlorophenols, vinyl chloride and 1,2-dichloroethan. The last discussed method is the chlorolysis [1, 7]. This method can be used for utilization of all types of waste chloroorganics. Separation of waste chloroorganic compounds by adsorption methods [8–11] has also been described in the article.
8
Content available Utilization of waste chloroorganic compounds
Myszkowski J., Milchert E., Bartkowiak M., Pełech R.
Polish Journal of Chemical Technology
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2010
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Vol. 12, nr 3
36-39
EN
Efficient methods of utilization of waste chloroorganic compounds coming from waste water and the waste streams formed e.g. in the production of vinyl chloride by dichloroethane method and in the production of propylene oxide by chlorohydrin method have been presented. First the separation of chloroorganic wastes by the adsorption methods has been described in the article. Three valuable methods of hlorocompounds utilization have been then discussed. The first one is isomerization of 1,1,2-trichloroethane to 1,1,1- trichloroethane as the valuable product with less toxicity than a substrate. The second method is ammonolysis of waste 1,2-dichloropropane and 1,2,3-trichloropropane. The third described method is chlorolysis. This method can be used for the utilization of all types of waste chloroorganics.
9
Content available remote Metody utylizacji odpadowych związków chloroorganicznych
Myszkowski J., Milchert E., Bartkowiak M., Pełech R.
Czasopismo Techniczne. Chemia
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2010
|
R. 107, z. 1-Ch
215-221
PL
W niniejszym artykule przedstawiono metody i możliwości wykorzystania odpadowych związków chlorooganicznych. Omówiono takie metody jak: izomeryzacja, wodoroodchlorowanie, amonoliza oraz chloroliza. Zastosowanie tych metod pozwala na zagospodarowania związków chloroorganicznych pochodzących ze ścieków i strumieni odpadowych, powstających np. podczas produkcji chlorku winylu metodą dichloroetanową i tlenku propylenu metodą chlorohydrynową.
EN
Methods of utilization of waste chloroogranic compounds has been presented. Isomerization, dehydrochlorination, ammonolysis and chlorolysis has been described as the efficient ways to utilize the chloroorganic compounds from waste streams from the production of vinyl chloride and propylene oxide.
10
Content available remote Wybrane aspekty zastosowania reakcji izomeryzacji w technologii bisfenolu A
Kulesza K., Tkacz B., German K., Bartoszewicz P.
Przemysł Chemiczny
|
2009
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T. 88, nr 6
678-681
11
Content available remote Synteza E-2-arylo-1-cyjano-1-nitroetenów
Jasiński R., Kwiatkowska M., Barański A.
Czasopismo Techniczne. Chemia
|
2006
|
R. 103, z. 4-Ch
41-46
PL
Zbadano reakcje aromatycznych aldehydów z nitroacetonitrylem. W przypadku reakcji z udziałem halogeno- i karbometoksybenzaldehydów otrzymano z dobrymi wydajnościami odpowiednie E-2-arylo-1-cyjano-1-nitroeteny.
EN
The reactions of various, aromatic aldehydes with nitroacetonitrile have been studied. In the case of halogen and carbomethoxy substituted benzaldehydes, E-2-aryl-1-cyano-1-nitroethenes were obtained with good yields.
12
Badanie węgla zawartego w warstwach malarskich metodą spektroskopii ramanowskiej
Szroeder P., Rozpłoch F., Marciniak W., Rogóż J., Flik J., Rogal R.
Karbo
|
2002
|
Nr 9
262-264
PL
Celem pracy było zbadanie możliwości zastosowania spektroskopii ramanowskiej do datowania dzieł sztuki. Przedmiotem badań był olej lniany, który jest powszechnie używany jako spoiwo farb olejnych. Zarejestrowano widma ramanowskie próbek olejów obejmujących ostatnie 20 lat. Efekt starzenia zinterpretowano jako skutek izomeryzacji i polimeryzacji. Zidentyfikowano pasma odpowiadające drganiom grup funkcyjnych C=O, O-C oraz O-H. Natężenie linii przypisywanej drganiom szkieletowym niesprzężonych wiązań w łańcuchach węglowodorowych w konformacji cis spada pod upływem czasu. Efekt ten jest wynikiem przejść konformacyjnych (cis-trans) i wysycania podwójnych wiązań węglowych. Widma starszych próbek wykazują silniejszą fluorescencję.
EN
The present study was undertaken to investigate the possibility of use of Raman spectroscopy for dating of artistic paintings. Linseed oil used commonly as binder of oil colors was examined. Raman spectra were recorded for new and aged (till 20 years) oils. The aging effects on the spectra of oils are interpreted as a result of both the positional and conformal isomerization and the polymerization. There were identified bands corresponding to oscillation modes of functional groups C=O, O-C and O-H. The intensity of the line attributed to backbone oscillations of no conjugated hydrocarbon double bonds in cw-conformation shows the time decrease. This effect results from the conformal transitions (cis-trans) and saturation of carbon double bonds. The spectra recorded from the older oils shows a more intensive fluorescence.
13
Physical image vs. structure relation, 5 [1]. Multinuclear NMR structural study on some hydrazones of O,O-Dialkyl 1-Oxoalkanephosphonates
Nazarski R. B., Gralak D. K., Kudzin Z. H.
Bulletin of the Polish Academy of Sciences. Chemistry
|
2000
|
Vol. 48, No. 1
27-33
EN
An unambiguous method for determination of the configuration of any single 0,0-dialkyl 1-oxoalkanephosphonate hydrazones based on H, C, P NMR data has been elaborated; the use of 1 JCp (P-C=N) couplings is the most fruitful. The 12C/13C isotope effects on the P chemical shifts of selected compounds have been measured. For primary hydrazones the E/Z isomerisation with stabilisation of their Z forms through an intramolecular H-bonding has been proven. In addition, for the latter stereoisomers small scalar couplings between H-bonded groups N-H.. .O=P have been found, JHP 2.4-3.4 Hz. The possibility of the across H-bridge transfer of spin-spin interactions in these forms is also discussed.
14
Isomerization of vegetable oils catalyzed by ruthenium complexes
Krompiec S., Suwiński J., Majewski J., Grobelny J.
Polish Journal of Applied Chemistry
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1998
|
Vol. 42, nr 1
43-48
EN
A study on isomerization of industrial oils - rapeseed, soybean, suntlower and linseed - was performed in the presence of the following ruthenium complexes: [RuHCl (CO)(PPh(3), [Ru(CO)3(PPh(3)2], [Ru(C2(1,5-COD)]x [Ru(acac)3], [RuCl2(PPh3)3)3], (RuH2(PPh3)]4], [RuCl2(AsPh3]3], [RuCl2(NBD)]x and [RuCl2(SbPh3)3]. The reactions were carried out in bulk under air atmosphere at 212st.C and 226st.C. Concentration of the complexes corresponded to 58 or 116 ppm of ruthenium. The best results were obtained with [RuHCl(CO)(PPh3)3 as the catalyst. Separation of the catalyst from isomerized oils was accomplished by sorption on diatomaceous earth or on active carbon. The isomerized rapeseed, soybean, sunllower and linseed oils were found to contain respectively 30, 54, 54 and 50 wt-% of conjugated isomers, up to 10 wt-% of polymeric materials and less than 1 ppm of ruthenium.
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