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Wyszukujesz frazę "carbon dioxide fixation" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
Ditlenek węgla w syntezie organicznej
Carbon dioxide in organic synthesis
Autorzy:
Burczyk, B.
Powiązania:
https://bibliotekanauki.pl/articles/172758.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Chemiczne
Tematy:
wiązanie ditlenku węgla
surowce odnawialne
synteza organiczna
kataliza
kompleksy metali przejściowych
carbon dioxide fixation
renewable resources
organic synthesis
catalysis
transition metal complexes
Opis:
Carbon dioxide is an abundant, cheap, almost nontoxic, thermodynamically stable, inert electrophile. Exploitation of CO 2 as a chemical feedstock, although will almost certainly not reduce its atmospheric concentration significantly, aims to generate high-value products and more-efficient processes. In recent years efficient transition-metal complexes have been used to perform homogeneously catalyzed transformations of CO 2 . This paper presents an overview of available catalytic routes for the synthesis of carboxylic acids, lactones, urea and carbamates, linear and cyclic carbonates as well as polycarbonates. Reduction processes of CO 2 are shortly men - tioned as well. C arboxylic acids have been synthesized via : (i) carboxylation of organolithium, organomagnesium (Scheme 2 [35]), organoboron (Scheme 3 [40 -42]), organozinc (Scheme 4 [43, 44]) and organotin (Scheme 5 [45, 46]) compounds; (ii) oxidative cycloaddition of CO 2 to olefins and alkynes (Scheme 6 -10 [47 -50, 57]) catalyzed by Ni(0)-complexes; (iii) transition-metal catalyzed reductive hydrocarboxylation of unsaturated compounds (Scheme 11, 12 [64 -67]); (iv) carboxylation of C-H bond (Scheme 13 [69 -71]). Telomerization of dienes, for instance 1,3-butadiene, and CO 2 in the presence of Ni(II) and Pd(II) complexes leads to lactones and esters of carboxylic acids (Scheme 14, 15 [73 -79]). Nucleophilic ammonia, primary and secondary amines react with CO 2 to give, respectively, urea and carbamic acid esters - carbamates and isocyanates (Scheme 16 -18 [94, 95]), thus eliminating the use of phosgene in their synthesis. CO 2 reacts with alcohols, diols and epoxides in the presence of transition-metal complexes (Fig. 2) and the reaction products are: linear carbonates (Scheme 20, 21 [110 -118]), cyclic carbonates (Scheme 22 -24 [153 -170]) and polycarbonates (Scheme 25, 26, Fig. 3, Tab. 1 [179 -186]). Finally, hydrogenation of CO 2 , leading to the formation of CO, HCOOH, CH 3 OH, CH 4 , C 2 H 6 and C 2 H 4 (Scheme 27), as well as electrochemical and photochemical reductions in the pre - sence of homogeneous and heterogeneous catalysts have been shortly reviewed.
Źródło:
Wiadomości Chemiczne; 2013, 67, 1-2; 1-53
0043-5104
2300-0295
Pojawia się w:
Wiadomości Chemiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristics of the spring/summer production in the Mecklenburg Bight (Baltic Sea) as revealed by long-term pCO2 data
Autorzy:
Schnaider, B.
Buecker, S.
Kaitala, S.
Maunula, P.
Wasmund, N.
Powiązania:
https://bibliotekanauki.pl/articles/47443.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Mecklenburg Bight
Baltic Sea
carbon dioxide
surface water
spring bloom
nitrogen fixation
Źródło:
Oceanologia; 2015, 57, 4
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Processes regulating pCO2 in the surface waters of the Central Eastern Gotland Sea: a model study
Autorzy:
Kuznetsov, I.
Neumann, T.
Schneider, B.
Yakushev, E.
Powiązania:
https://bibliotekanauki.pl/articles/48971.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Oceanologii PAN
Tematy:
Baltic Sea
biogeochemical modelling
brackish water
carbon dioxide
Cyanoprokaryota
detritus
ecological status
ecosystem
ERGOM model
nitrogen fixation
seasonal change
surface water
water exchange
Opis:
This work presents a one-dimensional simulation of the seasonal changes in CO2 partial pressure (pCO2). The results of the model were constrained using data from observations, which improved the model’s ability to estimate nitrogen fixation in the central Baltic Sea and allowed the impact of nitrogen fixation on the ecological state of the Baltic Sea to be studied. The model used here is the public domain water-column model GOTM (General Ocean Turbulence Model), which in this study was coupled with a modifed Baltic Sea ecosystem model, ERGOM (The Baltic Sea Research Institute’s ecosystem model). To estimate nitrogen fixation rates in the Gotland Sea, the ERGOM model was modified by including an additional cyanobacteria group able to fix nitrogen from March to June. Furthermore, the model was extended by a simple CO2 cycle. Variable C:P and N:P ratios, controlled by phosphate concentrations in ambient water, were used to represent cyanobacteria, detritus and sediment detritus. This approach improved the model’s ability to reproduce sea-surface phosphate and pCO2 dynamics. The resulting nitrogen fixation rates in 2005 for the two simulations, with and without the additional cyanobacteria group, were 259 and 278 mmol N m−2 year−1 respectively.
Źródło:
Oceanologia; 2011, 53, 3
0078-3234
Pojawia się w:
Oceanologia
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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