The anionic polymerization and oligomerization of 4-vinyl pyridine by methanolic alkali metal methoxides in DMSO was studied. The molecular weights increased with increasing monomer concentration and decreased with increasing methanol concentration. This fact was utilized in the preparation of oligo
Anionic oligomerization of acrylamide by alkali metal methoxides
β Scribed by Shmuel Dabi; Albert Zilkha
- Publisher
- Elsevier Science
- Year
- 1977
- Tongue
- English
- Weight
- 603 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0014-3057
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β¦ Synopsis
The anionic oligomerization of acrylamide by methanolic alkali metal methoxides was studied in methanol and in aprotic solvents. Oligomer yield increased with increasing initiator concentration, the dielectric constant of the solvent, the electropositivity of the alkali metal and with decrease in methanol concentration. Initiation occurred by addition of methoxide to the double bond. Simultaneous monitoring of the reactants and products showed that B-methoxypropionamide. first formed in up to 700o yield, undergoes a base-catalysed reversible reaction generating acrylamide which participates in propagation. Acid hydrolysis of the oligomers showed that propagation had proceeded through 1.2-addition (30-507.o) leading to an acrylamide structure, and 1,4-addition 150-70Β°o) leading to a ~-alanine structure in the polymers.
π SIMILAR VOLUMES
By the method of the absolute quantitative SEC, a process of anionic oligomerization of styrene, initiated by n-butyl lithium, was followed. The concentration of 1-5-mer monodisperse species in different reaction times can be obtained by HPSEC separation. The results shown that the propagation rate
## Abstract The influence of methyl substituent on the mechanism of the ringβopening polymerization of Ξ²βlactones initiated by alkali metal alkoxides is discussed. Attention has been paid to the effect of the substituent position in the monomer molecule on the ringβopening mechanism, the 3,3βdimeth