Show/Hide Menu
Hide/Show Apps
Logout
Türkçe
Türkçe
Search
Search
Login
Login
OpenMETU
OpenMETU
About
About
Open Science Policy
Open Science Policy
Open Access Guideline
Open Access Guideline
Postgraduate Thesis Guideline
Postgraduate Thesis Guideline
Communities & Collections
Communities & Collections
Help
Help
Frequently Asked Questions
Frequently Asked Questions
Guides
Guides
Thesis submission
Thesis submission
MS without thesis term project submission
MS without thesis term project submission
Publication submission with DOI
Publication submission with DOI
Publication submission
Publication submission
Supporting Information
Supporting Information
General Information
General Information
Copyright, Embargo and License
Copyright, Embargo and License
Contact us
Contact us
Coordination polymerization of cyclic ethers by metal xanthates and carbamates
Download
index.pdf
Date
2003
Author
Taş, Hüseyin
Metadata
Show full item record
Item Usage Stats
163
views
0
downloads
Cite This
Zinc xanthates are active catalysts in stereoregular polymerization of propylene oxide and markedly more stable than that of known classical stereoregular catalysts. But steric control of zinc xanthates is weaker. To find more effective catalyst systems the isopropyl xanthates of Cu, Pb, Ni, Fe, Al and Sn are investigated and only copper (Cu(isoPr)Xt) and tin (Sn(isoPr)Xt) isopropyl xanthates were appeared to be active, but Cu(isoPr)Xt yielded only low molecular weight product. Therefore Sn(isoPr)Xt system was investigated in detail in polymerization of propylene oxide (PO). Polymerization of PO with this catalyst produced two contrasting polymers; high molar mass, crystalline (K-polymer) and low molar mass (D-polymer). Formation of double bonds in D-polymer was thought to be due to as an anionic process. Polymerization reactions were studied by changing polymerization conditions and reacting catalyst with predetermined amount of water. It̕s found that Sn(isoPr)Xt have considerably low efficiency than that of Zn(isoPr)Xt catalyst. The yield linearly increases by increasing catalyst concentration. The propagation is competed by termination or transfer process hence overall activation energy is negative. Some mechanistic features of this system was also discussed. The catalytical activity of carbamates in this field has also been reported, without any information about catalytical efficiency and stereoregularity of the process. Therefore zinc diethyl dithiocarbamate was also studied and found as an active catalyst in stereoregular polymerization but it showed weaker efficiency in the PO polymerization than that of Zn(isoPr)Xt catalyst (about 12 times weaker).
Subject Keywords
Polymerization
,
Xanthates
URI
http://etd.lib.metu.edu.tr/upload/1225028/index.pdf
https://hdl.handle.net/11511/13447
Collections
Graduate School of Natural and Applied Sciences, Thesis
Suggestions
OpenMETU
Core
Electrochemical copolymerization of 2-substituted thiophene derivative linked by polyether bridge with thiophene
Cihaner, A; Önal, Ahmet Muhtar (2005-09-01)
New conducting copolymers have been synthesized via electrochemical oxidation of thiophene (Th) in the presence of monomer bis(2-thienyl)ethyl (1). Cyclic voltammetry (CV) studies showed that the presence of monomer I in the electrolytic solution greatly changes the CV behaviour of the formation of the polythiophene films. It is found that the increasing ratio of I was found to decrease electroactivity of copoly(I-Th). Electrochemical synthesis of copolymer films was achieved via constant potential electrol...
Benzyl functionalized benzotriazole containing conjugated polymers: effect of substituent position on electrochromic properties and synthesis of crown ether functionalized electrochromic polymers
Yiğitsoy, Başak; Toppare, Levent Kamil; Department of Chemistry (2011)
A new class of π-conjugated monomers was synthesized with combination of electron donating and electron-withdrawing heterocyclics to understand the effects of structural differences on electrochemical and optoelectronic properties of the resulting polymers. Electron deficient benzotriazole, substititued with benzyl from two available sites, coupled with stannylated electron donating groups, ethylenedioxythiophene (EDOT) and thiophene (Th), to yield four different monomers; 1-benzyl-4,7-di(thiophen-2-yl))-2H...
Electrochemical copolymerization of thiophene containing pseudo-polyether cages with pyrrole
Cihaner, Atilla; Önal, Ahmet Muhtar (2006-01-01)
Conducting copolymers were synthesized via the electrochemical oxidation of pyrrole (Py) in the presence of the monomer 1,12-bis(2-thienyl)-2,5,8,11-tetraoxadodecane (1). The presence of monomer I in the electrolytic solution greatly changed the CV behavior of Py during its potensiodynamic polymerization. The electroactivity of poly(I-co-Py) increased with the increasing amount of I in the comonomer mixture. Copolymer films were prepared via constant potential electrolysis in an electrolytic solution contai...
Enantioselective reduction of ketones with borane catalyzed by cyclic β- amino alcohols prepared from proline
Demir, Ayhan S; Mecitoglu, Idris; Tanyeli, Cihangir; Gülbeyaz, Volkan (Elsevier BV, 1996-12)
New catalysts have been prepared from (S)- and (R)- proline and the asymmetric borane reduction of prochiral ketones using these catalysts has been studied. The secondary alcohols were obtained in 76-95% yield with 57-96% enantiomeric excesses. Copyright (C) 1996 Elsevier Science Ltd
Aryl butenoic acid derivatives as a new class of histone deacetylase inhibitors: synthesis, in vitro evaluation, and molecular docking studies
Esiyok, Peruze Ayhan; Seven, Ozlem; Eymur, Guluzar; Tatar, Gamze Bora; DAYANGAÇ ERDEN, DİDEM; YELEKÇİ, Kemal; YURTER, HAYAT; Demir, Ayhan Sıtkı (The Scientific and Technological Research Council of Turkey, 2014-01-01)
New aryl butenoic acid derivatives have been synthesized by combining hydroxy- or methoxy-substituted phenyl rings as the capping group, with a double bond in the short linker as well as metal binding groups, enoic ester, and salts bearing either methyl or morpholine. These compounds have been shown to possess promising histone deacetylase inhibition activities via in vitro fluorometric assay and molecular docking studies.
Citation Formats
IEEE
ACM
APA
CHICAGO
MLA
BibTeX
H. Taş, “Coordination polymerization of cyclic ethers by metal xanthates and carbamates,” M.S. - Master of Science, Middle East Technical University, 2003.