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1
Content available remote Utlenianie limonenu tlenem cząsteczkowym katalizowane kompleksami manganu(II) i żelaza(II) z 2,2'-bipirydylem immobilizowanymi na nośniku bentonitowym
Sobkowiak A., Szczepanik A., Naróg D., Charczuk M.
Przemysł Chemiczny
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2015
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T. 94, nr 11
2006-2009
PL
Przedstawiono wyniki badań reakcji utleniania limonenu tlenem cząsteczkowym katalizowanej kompleksami żelaza(II) oraz manganu(II) z 2,2’-bipirydylem immobilozowanych na nośniku bentonitowym. Jako główne produkty otrzymano: tlenek 1,2-limonenu, karwon i karweol. Dla reakcji katalizowanych kompleksem bis(2,2’-bipirydyl)mangan(II) obserwowano większe wydajności produktów niż dla kompleksu bis(2,2’-bipirydyl)żelazo(II). Jeżeli zawartość katalizatora w bentonicie była równa jego stężeniu w roztworze w przypadku katalizy homogenicznej, wówczas wydajność produktów była mniejsza. Immobilizacja katalizatora umożliwia jednak łatwe oddzielenie katalizatora od mieszaniny poreakcyjnej oraz prowadzenie reakcji bez udziału rozpuszczalnika.
EN
A 5 mM limonene sample was oxidized with O₂ on complex Mn(II) or Fe(II) catalysts into a closed vessel with vol. of 22 mL at the catalyst-to-limonene ratio 0.5, 1, 10 and 15. The reaction was carried out at 23°C for 24 h. The reaction products were analyzed by gas chromatog. to det. the main components (1,2-limonene oxide, carvone and carveol). For both catalysts, an increase in yields of products with increasing amount of used catalyst were obsd. The Mn catalyst was more active than the Fe one. The replacing of air with O₂ resulted in increasing the reaction efficiency.
2
Content available remote Utlenianie limonenu tlenem cząsteczkowym i nadtlenkiem wodoru
Szczepanik A., Sobkowiak A.
Wiadomości Chemiczne
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2009
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[Z] 63, 7-8
601-634
EN
Limonene is one of the most abundant and readily available terpenes [5-7, 9-15]. It constitutes approximately 90% of orange and grapefruit peel oil [5] and hence it is potentially available in large amounts as a by-product of the citrus industry [21]. In contrast to relatively inexpensive limonene, products of its oxidation, such as: ?-terpineol, carveol, carvone, perillyl alcohol, menthol and limonene oxide, are compounds of a very high market value [16] and they are widely used (apart from the epoxide) in the flavor and fragrance industry [7]. Limonene oxide can be applied as a building block in the synthesis of drugs [18, 19] and biodegradable polymers [20]. Since an industrial method of limonene conversion into its ketone - carvone (used as a mint flavor for foods and oral hygiene products [7]) - involves several stages and the use of environmentally hazardous chemicals [21], it does not remain in accordance with 'green chemistry'. The latter problem concerns also the methods of limonene oxidation based on chromium(VI) compounds [25-28]. Hence a lot of attention is paid to limonene oxidation using environmentally benign oxidants, namely dioxygen and hydrogen peroxide. Literature studies revealed that a variety of approaches to limonene oxidation by oxygen and hydrogen peroxide had been published so far. The oxidation of limonene using dioxygen can be performed catalytically and photochemically [80-86]. Generally, a complex mixture of limonene oxidated derivatives is obtained using Wacker-like systems [44-51] as well as all sorts of cobalt catalysts [52-56]. Transition metal complexes can also activate dioxygen for the oxidation of limonene giving a mixture of products [78, 79]. Limonene epoxides are usually produced by Mukaiyama systems, where peracid is in-situ generated from oxygen, aldehyde and transition metal complex [59-77]. The oxidation of limonene by hydrogen peroxide usually leads to its epoxidation [90-98, 100, 101]; however, sometimes other limonene derivatives are formed [99, 134-136]. Limonene oxidation using hydrogen peroxide proceeds in the presence of catalysts which are transition metal complexes [90-105], heteropolyanions [109-120], aluminum oxide [121-125] as well as titanium-containing catalysts [126-131]. Furthermore, hydrogen peroxide reacts with nitriles forming peroxycarboximidic acid which can epoxidize limonene in Payne reaction [132, 133].
3
Electrocatalytic Behavior of a Carbon Paste Electrode Modified with Iron(III)tetracyanophenylporphyrin Chloride Towards Dioxygen Reduction
Shamsipur M., Najafi M., Milani Hosseini M. R., Sharghi H.
Polish Journal of Chemistry
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2009
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Vol. 83, nr 6
1173-1183
EN
The electrochemical behavior and ability of a carbon paste electrode modified with iron(III)tetracyanophenylporphyrin chloride (FeTCPP-Cl) as a potential electrocatalyst for the reduction of dioxygen to hydrogen peroxide was investigated using cyclic voltammetry (CV), dou ble-potential step chronoamperometry, and hydrodynamic voltammetry at the rotating disk electrode. The modified electrode showed an excellent electrocatalytic behavior, with respect to reduction of dioxygen in acidic aqueous solu - tions with an overpotential of 750 mV lower than that at the blank carbon paste electrode. Some kinetic parameters for the process were determined from the RDE voltammetry experiments using the Koutecky-Levich plot analysis. Based on the results obtained, a mechanism of the electrocatalysis was proposed.
4
Uptake of Molecular Oxygen by Co(II) Chelates with Peptides in Aqueous Solution. Part XII. Non-covalent Interactions in the Cobalt(II) - Diastereoisomeric Phenylalanyl Dipeptide Systems. Effect on Kinetics of Oxygenation
Kufelnicki A., Świątek A.
Polish Journal of Chemistry
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2008
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Vol. 82, nr 5
981-991
EN
The interactions of Co(II) with a group of diastereoisomeric dipeptides containing a side chain with the aromatic phenyl ring have been studied in aqueous solution, both under inert atmosphere and in the presence of dioxygen. An effect of stereoselectivity has been observed in the metal promoted deprotonations, examined by glass electrode potentiometry and correlated with the results of UV/Vis spectroscopy. The kinetics of oxygenation were studied by the stopped flow method and related to the potentiometric results.
5
Unexpected Catalytic Activity of N-Hydroxyphthalimide Combined with Some Co-catalyst in Oxidation of Organic Substrates by Dioxygen
Figiel P., Sobczak J. M.
Polish Journal of Chemistry
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2001
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Vol. 75, nr 6
869-873
6
Electroreduction of Dioxygen Catalyzed by Ferric Carboxymethylene-Cyclam Complex
Szulbiński W.
Polish Journal of Chemistry
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2000
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Vol. 74, nr 8
1163-1175
EN
On the basis of the electrochemical and spectroscopic data, mechanistic studies on the subject complex reactivity towards O2 are reported.
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