Kinetics of quaternization reactions of polymeric amines

1989 ◽  
Vol 54 (3) ◽  
pp. 663-672
Author(s):  
Martin Přádný ◽  
Stanislav Ševčík ◽  
Stela Dragan
Keyword(s):  
Alkylating Agent ◽  
Alkyl Halides ◽  
Differential Rate ◽  
Hydroxyethyl Methacrylate ◽  
Ethyl Methacrylate ◽  
Slowing Down ◽  
Conformational Effects ◽  
Alkylation Reactions ◽  
Kinetics Of ◽  
Steric Hindrances

The paper deals with kinetics phenomena occurring in the quaternization of some polymeric amines, such as poly[2-(dimethylamino)ethyl methacrylate], poly{N-[3-(dimethylamino)propyl]-acrylamide}, and poly[2-(dimethylamino)ethyl methacrylate-co-2-hydroxyethyl methacrylate], with alkyl halides. The accelerating and slowing-down effects which take place in the alkylation reactions are discussed on the basis of the reaction course, i.e. of the dependence of differential rate constants on the conversion fraction of the reaction. Accelaration of the reaction is affected by the increasing polarity of microsurroundings of the reacting groups, while electrostatic and steric hindrances of the reacted groups slow down the reaction. Conformational effects, chemical and solvation interactions in the polymer-solvent-alkylating agent system and tacticity of the polymer are also operative.

Kinetics of the anionic polymerization of 2-(tertbutyldimethylsilyloxy) ethyl methacrylate

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Thomas Breiner ◽  
Hans-Werner Schmidt ◽  
Axel H. E. Müller
Keyword(s):  
Anionic Polymerization ◽  
Gel Permeation Chromatography ◽  
Butyl Methacrylate ◽  
Side Reactions ◽  
Polymerization Temperature ◽  
Hydroxyethyl Methacrylate ◽  
Controlled Polymerization ◽  
Ethyl Methacrylate ◽  
Reported Data ◽  
Kinetics Of

AbstractThe kinetics and the extent of side reactions of the anionic polymerization of silyl-protected 2-hydroxyethyl methacrylate, 2-(tert-butyldimethylsilyloxy)ethyl methacrylate (TBDMS-HEMA), in tetrahydrofuran (THF) were studied as a function of polymerization temperature. Lithium chloride was added in order to achieve a controlled polymerization. The results of polymerizations at various temperatures are compared with reported data for methyl methacrylate and tert-butyl methacrylate in THF. The activation energy for the studied monomer is lower compared to the other methacrylates. Gel permeation chromatography-viscosity studies show that poly(TBDMS-HEMA) exhibits a more wormlike structure in THF than other polymethacrylates, as indicated by a higher Mark-Houwink exponent, α = 1.025.

Kinetics of the temperature-induced volume phase transition in poly(2-(2-methoxyethoxy)ethyl methacrylate) hydrogels of various topologies

Polymer ◽  
2017 ◽  
Vol 110 ◽  
pp. 25-35 ◽  
Author(s):  
Marcin Pastorczak ◽  
Lidia Okrasa ◽  
Jeong Ae Yoon ◽  
Tomasz Kowalewski ◽  
Krzysztof Matyjaszewski
Keyword(s):  
Phase Transition ◽  
Volume Phase Transition ◽  
Volume Phase ◽  
Ethyl Methacrylate ◽  
Kinetics Of

Mechanism of formation of Grignard reagents. Kinetics of reaction of alkyl halides in diethyl ether with magnesium

1980 ◽  
Vol 102 (1) ◽  
pp. 217-226 ◽  
Author(s):  
Harold R. Rogers ◽  
Craig L. Hill ◽  
Yuzo Fujiwara ◽  
Randall J. Rogers ◽  
H. Lee Mitchell ◽  
...  
Keyword(s):  
Diethyl Ether ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Mechanism Of Formation ◽  
Kinetics Of Reaction ◽  
Kinetics Of

Transport kinetics of methanol in hydroxyethyl methacrylate homopolymer and its copolymers

2004 ◽  
Vol 19 (11) ◽  
pp. 3359-3363 ◽  
Author(s):  
C-S. Tsai ◽  
Sanboh Lee ◽  
Tinh Nguyen
Keyword(s):  
Continuous Phase ◽  
Transport Processes ◽  
Hydroxyethyl Methacrylate ◽  
Nominal Thickness ◽  
Methacrylate Copolymers ◽  
Different Temperatures ◽  
Free Energy Of Mixing ◽  
D Values ◽  
Increasing Temperature ◽  
Kinetics Of

The kinetics of methanol transport in 2-hydroxyethyl methacrylate (HEMA) homopolymer and 75/25 and 50/50 mol fraction HEMA/DHPMA (2,3-dihydroxypropyl methacrylate) copolymers at five different temperatures has been investigated using the sorption experiment technique. A combined case I and case II diffusion model was used to describe the transport processes. Four replicates for each temperature of each material having a nominal thickness of 0.1 mm were immersed in methanol maintained at 35, 40, 45, 50, and 55 °C, and the mass uptake as a function of time was measured gravimetrically. Experimental results are found to be in good agreement with model prediction at all temperatures and for all three materials. Both the diffusion coefficients of case I transport and velocity of case II transport increase with increasing temperature. D values at low temperatures (35 and 40 °C), which are in the 10−9 cm2/s range, of the HEMA homopolymer are less than those of the copolymers. On the other hand, the activation energies of case I transport of the copolymers are substantially higher than those of the HEMA homopolymer; however, the level of DHPMA loading in the copolymer does not seem to affect the activation energy. In addition, thermodynamic heat and free energy of mixing values indicate heat is released when HEMA/DHPMA copolymers are exposed to methanol and that the solvent/copolymer systems exist as a continuous phase. In contrast, the methanol/HEMA homopolymer system exists as separate phases.

The increase in intracellular pH associated with Xenopus egg activation is a Ca(2+)-dependent wave

1992 ◽  
Vol 101 (1) ◽  
pp. 55-67 ◽  
Author(s):  
N. Grandin ◽  
M. Charbonneau
Keyword(s):  
Cell Cycle ◽  
Intracellular Ph ◽  
Egg Activation ◽  
Free Calcium ◽  
Slowing Down ◽  
M Phase ◽  
Xenopus Egg ◽  
General Slowing ◽  
The Impact ◽  
Kinetics Of

In Xenopus eggs, the transient increase in intracellular free calcium ([Ca2+]i), or Ca2+ transient, which occurs 1–3 min after egg activation, is likely to be partly responsible for the release of the cell cycle blockade. In the present study, we have used microinjection of BAPTA or EGTA, two potent chelators of Ca2+, to buffer [Ca2+]i at various steps during Xenopus egg activation and evaluate the impact on some of the associated events. Microinjection of either one of the Ca2+ chelators into unactivated eggs prevented egg activation without, however, lowering [Ca2+]i, suggesting that only physiological [Ca2+]i changes, but not [Ca2+]i levels, were affected by the Ca2+ buffer. When BAPTA was microinjected around the time of occurrence of the Ca2+ transient, the egg activation-associated increase in intracellular pH (pHi) was clearly delayed. That delay was not due to a general slowing down of the cell cycle, since under the same conditions of microinjection of BAPTA the kinetics of MPF (a universal M-phase promoting factor) inactivation were unaffected. These results represent the first indication that the Ca2+ transient participates in determining the time of initiation of the pHi increase during Xenopus egg activation. The present results also demonstrate that the egg activation-associated pHi changes (a slight, transient decrease in pHi followed by a permanent increase in pHi) proceed as a wave propagating from the site of triggering of egg activation. Experiments of local microinjection of BAPTA support the view that the pH wave is a consequence of the Ca2+ wave, which it follows closely.

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