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001-es BibID:BIBFORM116035
035-os BibID:(WoS)001048397500001 (Scopus)85169565923
Első szerző:Juhász Anett
Cím:The kinetics of uncatalyzed and catalyzed urethane forming reactions of aliphatic diisocyanates with butan-1-ol / Anett Juhász, Üneri Haymana Serra, Csilla Lakatos, Bence Vadkerti, Anita Rágyanszki, Ödön Farkas,Sándor Kéki, Lajos Nagy
Dátum:2023
ISSN:1144-0546 1369-9261
Megjegyzések:The kinetics of the urethane forming reactions of hexamethylene diisocyanate (HDI), 4,4·-dicyclohexyl-methane-diisocyanate (HMDI) and isophorone diisocyanate (IPDI) with butan-1-ol were systematically studied by electrospray ionization mass spectrometry (ESI-MS) in the off-line mode. The reactions were performed in toluene solution in the temperature range of 50?80 ?C and perdeuterated butan-1-ol was used for quenching the reaction. The butan-1-ol was employed in high excess to diisocyanates to obtain pseudo first-order rate coefficients. For rendering the kinetics, a simple A ? B ? C consecutive model was applied and found to adequately describe the observed kinetic behaviors. The corresponding rate coefficients were determined and reactivities of the diisocyanates were found to decrease in the order HDI > IPDI > HMDI. Furthermore, it was observed that the second isocyanate group in HDI, due to the ring formation by intramolecular hydrogen bonds, reacted faster with butan-1-ol after the first isocyanate moiety had reacted. The formation of hydrogen bonding rings was also confirmed by DFT calculations. However, the reactivity of the second isocyanate moiety (after the first one has reacted) did not change significantly in the case of HMDI. From the temperature dependences the apparent activation parameters such as the pre-exponential factors and activation energies were determined. In addition, the reactions were also studied at 80 ?C in the presence of tin(II)-2-ethylhexanoate at different concentrations and a mechanism was proposed for the catalytic process.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
HDI, HMDI
Megjelenés:New Journal Of Chemistry. - 47 : 34 (2023), p. 16096-16107. -
További szerzők:Serra, Üneri Haymana Lakatos Csilla (1990-) (környezetmérnök) Vadkerti Bence (1994-) (okleveles vegyészmérnök) Rágyanszki Anita Farkas Ödön Kéki Sándor (1964-) (polimer kémikus) Nagy Lajos (1979-) (vegyész)
Pályázati támogatás:FK-128783
Egyéb
TKP2021-EGA-20
Egyéb
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
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2.

001-es BibID:BIBFORM081791
035-os BibID:(WoS)000488843000029 (Scopus)85072823438
Első szerző:Nagy Lajos (vegyész)
Cím:Eight out of eight : a detailed kinetic study on the reactivities of the eight hydroxyl groups of sucrose with phenyl isocyanate / Lajos Nagy, Bence Vadkerti, Gyula Batta, Péter Pál Fehér, Miklós Zsuga, Sándor Kéki
Dátum:2019
ISSN:1144-0546 1369-9261
Megjegyzések:In this paper a detailed kinetic study between sucrose (S) and phenyl isocyanate (PI) in dimethylsulfoxide is reported for the first-time. In order to obtain monosubstituted sucrose derivatives overwhelmingly, i.e., when only one phenyl isocyanate molecule is attached to sucrose, sucrose was applied in a high molar excess to isocyanate (the molar ratio of S/PI was 16/1). Such an experimental setup indeed resulted in the formation of eight different sucrose derivatives which were separated and detected by high performance liquid chromatography combined with UV spectroscopy and mass spectrometry (HPLC-UV/MS). Under these experimental conditions, the disubstituted sucrose derivatives formed could be detected only in a few percent (ca. 2% with respect to the monosubstituted sucrose derivatives). Furthermore, by means of HPLC-UV/MS, HPLC-UV/MS/MS and NMR methods such as 1H-, 13C-NMR and 2D-NMR the reactivity of each of the eight OH groups of sucrose was determined. It was found that the most reactive moieties of sucrose are the three primary OH groups (hydroxymethyl) and the reactivity of the sucrose's OH groups decreases in the order of k(OH)60(1) > k(OH)6(0.84) > k(OH)10(0.31) > k(OH)3(0.25) > k(OH)4(0.23) > k(OH)2(0.13) > k(OH)40(0.11) > k(OH)30(0.09), where the numbers in subscript and in brackets represent the OH position in sucrose and the relative reactivity with respect to that of the highest one. The reactivity order is in line with the Mulliken charges of the OH groups of sucrose calculated by density functional theory (DFT) and also with those expected according to the theory of chromatographic separation. The dependences of the relative reactivities on temperature were also investigated and the differences between the corresponding activation parameters were also determined and discussed.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:New Journal of Chemistry. - 43 : 38 (2019), p. 15316-15325. -
További szerzők:Vadkerti Bence (1994-) (okleveles vegyészmérnök) Batta Gyula (1953-) (molekula-szerkezet kutató) Fehér Péter Pál (1991-) (vegyész) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus)
Pályázati támogatás:GINOP-2.3.3-15-2016-00021
GINOP
GINOP-2.3.3-15-2016-00004
GINOP
GINOP-2.3.2-15-2016-00008
GINOP
FK-128783
OTKA
Internet cím:Szerző által megadott URL
DOI
Intézményi repozitóriumban (DEA) tárolt változat
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3.

001-es BibID:BIBFORM106869
035-os BibID:(Wos)000793118700001 (Scopus)85131372481
Első szerző:Vadkerti Bence (okleveles vegyészmérnök)
Cím:Reactivity of multi-arm polyols towards isocyanates / Bence Vadkerti, Anett Juhász, Csilla Lakatos, Miklós Zsuga, Sándor Kéki, Lajos Nagy
Dátum:2022
ISSN:1144-0546 1369-9261
Megjegyzések:In this research, the kinetics of the reaction of various polymer polyol crosslinking agents with phenyl isocyanate is reported. Pentaerythritol (PE), trimethylol propane (TMP), ethoxylated (PEEO) and propoxylated (PEPO) pentaerythritol oligomers as well as Petol PA 500-5D (a propoxylated diethylenetriamine with 5 arms) were used as crosslinking agents. These polyols were applied in high molar excess to isocyanate to obtain pseudo first-order rate dependencies. The reaction products were separated by HPLC and detected by UV absorption. It was found that trimethylol propane (kTMP = 0.0819 min?1), due to its electron donating group, was slightly more reactive than pentaerythritol (kPE = 0.0700 min?1). Moreover, ethoxylated and propoxylated derivatives were found to be less reactive than PE, which can be explained by the electron withdrawing property of the alkoxy groups. In addition, Petol PA 500-5D was determined to be the most reactive polyol, which is ascribed to the fact that it carries some catalytic properties similar to other tertiary amine catalysts. Furthermore, the reactions were also carried out in high isocyanate molar excess to polyols in order to determine how the number of reacted hydroxyl groups influences the reactivity of unreacted hydroxyl groups. The separation of the products could be achieved by HPLC for PE and TMP; however, in the case of PEEO, PEPO and Petol PA 500-5D, due to the high number of products, MALDI-TOF MS was applied. The results clearly showed that the reactivity of the unreacted OH groups significantly changed upon reaction in the case of PE and TMP, while for the polymer polyols, steric and inductive effects slightly modified the relative reactivities of the OH groups in each crosslinking agent.
Tárgyszavak:Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban
folyóiratcikk
Megjelenés:New Journal Of Chemistry. - 46 (2022), p. 9871-9879. -
További szerzők:Juhász Anett Lakatos Csilla (1990-) (környezetmérnök) Zsuga Miklós (1944-) (polimer kémikus) Kéki Sándor (1964-) (polimer kémikus) Nagy Lajos (1979-) (vegyész)
Pályázati támogatás:GINOP-2.3.3-15-2016-00021
GINOP
TKP2021-EGA-20
Egyéb
FK-128783
Egyéb
Internet cím:Intézményi repozitóriumban (DEA) tárolt változat
DOI
Borító:
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