## Abstract Di‐__tert__‐butyl 2‐lithio‐2,4,4‐trimethylglutarate (1) as a model of the living dimer of __tert__‐butyl methacrylate was studied in deuterated tetrahydrofuran (THF‐__d__~8~) solution by ^6^Li, ^7^Li, ^1^H and ^13^C NMR. In agreement with earlier observations from infrared spectroscopy
Study of the propagation centre in the anionic polymerization of acrylic monomers, 1. Spectroscopic study of methyl 2-lithioisobutyrate, an initiator for the anionic polymerization of acrylic monomers
✍ Scribed by Jaroslav Kříž; Jiří Dybal; Petr Vlček; Miroslav Janata
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 824 KB
- Volume
- 195
- Category
- Article
- ISSN
- 1022-1352
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
As the simplest model for the propagation centre in the anionic polymerization of methyl methacrylate, the solution of methyl 2‐lithioisobutyrate (1) in tetrahydrofuran was studied by means of ^1^H, ^6^Li, ^7^Li and ^13^C nuclear magnetic resonance (NMR), and Raman spectroscopy at various concentrations and temperatures. A system of equilibria of differently solvated dimeric, tetrameric and two isomeric trimeric aggregates was found and their thermodynamic constants were established. On the basis of the analysis of NMR chemical shifts, heteronuclear nuclear Overhauser effect correlation spectroscopy (NOESY) spectra and relaxation data, structures of the aggregates are suggested. The kinetics of the exchange between the aggregates and the lifetime of individual aggregates was established. The results suggest that the aggregation can interfere with initiation in the early steps of anionic polymerization of acrylics.
📜 SIMILAR VOLUMES
## Abstract Using ^1^H, ^6^I i, ^7^Li and ^13^C NMR, di‐__tert__‐butyl 2‐lithio‐2,4,4‐trimethylglutarate (A) as a dimeric model of the living poly(__tert__‐butyl methacrylate) is shown to form well‐defined aggregates with lithium __tert__‐butoxide (B) in tetrahydrofuran. The prevailing aggregates w
## Abstract Solutions of Li, Na and K salts of 3,3‐dimethyl‐2‐piperidone and ε‐caprolactam in dimethyl sulfoxide‐__d__~6~ were studied by ^6^Li, ^7^Li, ^23^Na, ^1^H and ^13^C NMR, Raman spectroscopy and MNDO molecular orbital calculations. Using NMR relaxation, the dynamics and equilibrium states o
## Abstract In contrast to methyl 2‐lithioisobutyrate (I), __tert__‐butyl 2‐lithioisobutyrate (A) in tetrahydrofuran (THF) appears to have one form only, irrespective of concentration (0,1‐0,8 mol/L) or temperature (203–273 K). According to its relaxation characteristics, this form probably is a te
## Abstract Interaction of potassium 3,3‐dimethyl‐2‐piperidone with 1‐benzoyl‐3,3‐dimethyl‐2‐piperidone in DMSO as a model of the complex propagation centre in the anionic polymerization of lactams has been studied by ^1^H and ^13^C NMR, infrared spectroscopy, and, for the Li counterion, by MNDO ca
The bulk polymerization of 2-allylphenylscrylic ester and of 2-allylphenylmethacrylic ester at 60-80°C. was studied. It was observed that under these conditions azobisisobutyronitrile, lauroyl peroxide, and benzoyl peroxide have satisfactory activity as initiators. The influence of atmospheric oxyge