Kinetik der hydrolytischen Lactampolymerisation auf Grundlage der neuesten Mechanismusvorstellungen

Abstract

Die Kinetik der hydrolytischen Lactampolymerisation rnit verschiedenen Initiatoren wurde untersucht. Die experimentellen Ergebnisse wurden auf Grundlage eines Mechanismus, der die Bildung und die Reaktionen der Amidinverbindungen beriicksichtigt, interpretiert. Ein kinetisches Modell wird vorgestellt. Die rnit diesem Modell berechneten Werte werden mit eigenen Messungen und Literaturdaten verglichen. Die Geschwindigkeits-und Gleichgewichtskonstanten werden abgeschatzt. Die rnit diesen Konstanten berechneten Werte zeigen eine befriedigende Ubereinstimmung mit den experimentellen Werten und Literaturangaben. Kunemuna zuapommuwcmii nommepuaayuu e-zanpoJzanmdnta na ocnoeanuu eoepefiennw npei3cmaeJcenuii o fiexanuafie B p a 6 O T e H c c n e A o B a n a c b K m e T n K a rHZponwi"YecKot n o n~~e p~s a q~~~ 6 -K a n p o n a m a M a B IIPHCYTCTBEIH pa3nk1sa~a.x B H H M a m e 06paaosa~ne EI p e a K q m o aMHAHHosMx c o e A m e H m t . Peaynmaw p a c q e T o B , n p o B o A m m x H a O c H o B a H n nHHHqHaTOPOB. PesyJIbTaTbI aKCnepHMeHTOB OqeHkIBaJIHCb C TOqKH 3peHIIR HOBOrO MeXaHM3Ma, IIpHHkIMaIOLQeI'O BO IIpeAJlaraeMOfi aBl'OpaMH KHHeTElqeCKOt MOAeJIH, CPaBHHBaJlHCb C aCKIIepEIMeHTajIbHbIMkI pe3yJlbTaTaMU, nOJIy¶eHHbIMH CaMbIMH aBTOpaMH, a TPKH(e HMeIOqHMHCR B JIHTepaType. PaCCYHTbIBaJlHCb KOHCTaHTbI CKOpOCTei EI p a B H 0 B e C H t BMlueynOMITHyTOi PeaKJJHH. PaCWTHhIe pe3yJibTaTbI IIOKa3bIBaIOT XOpOluOe COOTBeTCTBkIe C aKCIIepHMeHTaJIbHMMH AaHHbIMII, IIOJIyqeHHbIMEI HBK aBTOpaMH TaK H B JlEITepaType. Kinetics of hydrolytic polymerization of caprolactam based on the most recent conception of mechanismThe kinetics of hydrolytic polymerization of &-caprolactam was investigated with various initiators. The experimental results are interpreted in terms of the reaction scheme proposed earlier, which takes into account the formation and reactions of amidin groups. A kinetic model is suggested and the rate and equilibrium constants were estimated. By variation of the parameters sufficient agreement between calculated values and measured or literature data was reached.

Pharmaceutical and Macromolecular Technologies in the Spirit of Industry 4.0

“…Polymerization of lactames and acrylates, investigated by Bertalan and Anna [1,2], reinforced the macromolecular chemistry knowledge in the first macromolecule school of Hungary founded by Zoltan Csűrös.…”

Modeling Equilibrium Behavior of Nylon 6, Nylon 6,6 and Nylon 6/6,6 Copolymer

“…These additional reactions are summarized in Table 4 and they can influence the equilibrium concentrations of end groups and may be useful for obtaining an improved understanding of apparent polycondensation equilibria. For example, terminal cyclic amidine ends have been observed during the polymerization of caprolactam at low water concentrations and relatively high temperatures (≥254 °C) . Bertalan et al.…”

“…Similar to reaction R3, amidine ends can open the caprolactam ring (reaction R14 in Table ). Also, caprolactam is regenerated by backbiting involving terminal amidine ends (reverse reaction R14) . To our knowledge, no experimental study has been performed specifically to obtain measured K 3a values because K 1 and K 2 provide information about K 3 as shown in Equation .…”

Improved Kinetic Rate Constants for Nylon 6, Nylon 6,6, and Nylon 6/6,6 Copolymer

“…As shown in Table 5, amidine ends can react with carboxyl ends (reaction R7) to produce amide links and can also be hydrated to form regular amine ends (reaction R8) 56–59. To our knowledge, no literature information is available about the reaction kinetics involving amidine ends.…”

“…If there are difficulties in fitting additional equilibrium data, then activity coefficients and associated correlations could be introduced in the model. If equilibrium data can be fitted appropriately using the equations in Table 4, but there are discrepancies when predicting reaction rates, the model could be extended by considering that amidine ends also participate in polyaddition addition reactions (i.e., reactions analogous to R3 and R5), especially when water concentrations are low 57…”