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Reakcje utleniania wybranych grup funkcyjnych z wykorzystaniem oxone® jako źródła tlenu cząsteczkowego

Zawadzki P., Czardybon W., Chrobok A.

Wiadomości Chemiczne

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2016

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[Z] 70, 5-6

289--297

EN

Oxidation reactions belong to the group of the most commonly used processes in both organic and inorganic chemistry. The main issues in such transformation are usually safe handling of the oxidants as well as waste generation. Peroxymonosulfuric acid is one of the strongest oxidants. It was described for the first time in 1898 by Heinrich Caro. Nowadays, the commercial sources of KHSO5 are low-cost industrial bulk chemicals, e.g., the triple salt Oxone® (2KHSO5· KHSO4·K2SO4). These products are stable oxidizing agents commonly used in fine chemicals synthesis, and are easy to handle, non-toxic as well as generate non-polluting by-products. Over the past several years the scope of its use has extended. One of the most important transformation that have been made possible with the use of Oxone® are epoxidation and ketone formation. Epoxides and ketones are important synthetic building blocks widely used in the chemical industry for the production of pharmaceutical products, flavours, fragrances, resins, adhesives and paints. The use of Oxone® was demonstrated in several combinations both in classical methods that involved metal catalysis as well as in novel approaches with the use of microwaves and ionic liquids. Over the past 20 years, ionic liquids, together with supercritical fluids and water, have become powerful alternatives to conventional organic solvents. Ionic liquids are salts having in the structure an organic cation and an inorganic or organic anion, with a melting point below 100°C. The advantage of using ionic liquids is a big variety of available structures. Combinations of both ionic liquids and Oxone® offer an interesting alternative to classical oxidation methods used in industry.

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Odkształcenia sprężyste struktury tworzywo epoksydowe-metal przy frezowaniu czołowym

Furmanowicz A., Kuczmaszewski J., Pieśko P.

Przetwórstwo Tworzyw

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2016

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T. 22, Nr 4 (172)

250--256

PL

Skrawalność tworzyw epoksydowych istotnie różni się od skrawalności metali. W dużym stopniu decyduje o tym różnica w wartościach modułu Younga tych materiałów. W wielu współczesnych konstrukcjach stosuje się elementy których fragmenty zbudowane są zarówno z metali jak i tworzyw polimerowych. Z takimi sytuacjami spotykamy się również w konstrukcjach sklejanych. W niektórych przypadkach takie elementy są równocześnie obrabiane w procesach skrawania. Podatność na odkształcenia pod wpływem sił skrawania, różna dla elementów metalowych i dla tworzyw polimerowych, może być przyczyną błędów wymiarów. W pracy frezowano strukturę stop aluminium - tworzywo epoksydowe i analizowano różnice wartości odkształcenia po obróbce. Przedstawiono wyniki badań oraz wnioski.

EN

A machinability of epoxide plastics is significantly different than machinability of metals. The differences of Young modulus of these materials are mainly deciding about this. A lot of modern constructions are build both from metals and plastics. The same situation we observe in adhesive joints of different materials. In some cases these elements are machined simultaneously. The deformability of elements affected by cutting forces is different for metal and plastics, so it makes a contribution to dimensional error. The metal-epoxide structures were machined and the differences in their strain after machining were analysed. In the end of the paper the results and conclusions were presented.

3

Cross-linked epoxy-isocyanate blends containing Epidian-6 modified by glycols

Bratychak M., Ivashkiv O., Bruzdziak P., Namiesnik J., Shyshchak O.

Polimery

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2016

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T. 61, nr 5

316--321

EN

Polymeric films of cross-linked structure may be formed using epoxy-isocyanate blends composed of Epidian-5 epoxy resin, 4,4'-diphenylmethanediisocyanate (MDI), Z-1 polyamine hardener and Epidian-6 epoxy resin modified by glycols. The effect of the component natures and ratio, process temperature and time on the gel-fraction content, as well as film hardness, was examined. The chemistry of the film forming process was determined using infrared-spectroscopy (IR).

PL

Z mieszaniny epoksydowo-izocyjanianowej, otrzymanej z żywicy epoksydowej Epidian-5, utwardzacza Z-1 i diizocyjanianu 4,4'-metylenodifenylu (MDI), oraz żywicy epoksydowej Epidian-6 zmodyfikowanej glikolami wytwarzano folie polimerowe o usieciowanej strukturze chemicznej. Oceniano wpływ składu jakościowego i ilościowego mieszaniny, temperatury oraz czasu reakcji na zawartość frakcji żelowej gotowych folii polimerowych i ich twardość. Przebieg procesu formowania folii badano metodą spektroskopii w podczerwieni (IR).

4

N-Substituted 5-Aryl-1,3-oxazolidin-2-ones from Arylethylene Oxides

Wróbel Z., Bobin M., Karczewski R.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 6

907-912

EN

Substituted 5-aryl-1,3-oxazolidin-2-ones can be efficiently prepared from arylethylene oxides and tert-butyl alkylcarbamates in the presence of catalytic amount of potassium tert-butoxide as a base. Their further hydrolysis under basic conditions provides aryl substituted aminoethanols in high yields.

5

Mechanistic studies on the oxidation of acrylic acid by quinolinium chlorochromate (QCC)

Mishra K., Singh J. V., Pandey A.

Bulletin of the Polish Academy of Sciences. Chemistry

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2003

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Vol. 51, No. 1

15-23

EN

The kinetics of oxidation of acrylic acid with a recently developed new mild Cr(VI) reagent quinolinium chlorochromate (QCC) has been investigated in acetic acid-water mixture (50% v/v). The order in [QCC], [acrylic acid] and [H+] is unity. The increase in the amount of acetic acid in its reaction mixture increases the rate. The effect of ionic strength is negligible. The reaction rates have been determined at different temperatures and the activation parameters have been computed. Stoichiometry indicates that one mole of acrylic acid reacts with one mole of QCC. The mechanism consistent with the observed results has been discussed.

6

Kinetics and mechanism of oxidation of some unsaturated organic substrates by quinolinium chlorochromate

Mishra K., Singh J. V., Pandey A.

Bulletin of the Polish Academy of Sciences. Chemistry

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2003

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Vol. 51, No. 1

25-33

EN

The oxidation of unsaturated organic compounds, viz. crotyl alcohol, allyl alcohol, crotonaldehyde and maleic acid by quinolinium chlorochromate (QCC) in acetic acid-water medium (50% v/v) leads to the formation of corresponding epoxide. The reaction is of first order each in QCC and the reductant. The reaction is catalysed by hydrogen ions. The increase in dielectric constant of the medium decreases the rate, while variation I in ionic strength has no perceptible change in rate. The reaction rates have been determined at different temperatures and the activation parameters have been evaluated. The mechanism consistent with the observed results has been discussed.