Mapping Dithiobenzoate-Mediated RAFT Polymerization Products via Online Microreactor/Mass Spectrometry Monitoring
2-cyano-2-propyl dithiobenzoates (CPDB)-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization was monitored by online flow microreactor/mass spectrometry. This enabled the reactions to be followed in a time-resolved manner, closely resolving product patterns in the reaction...
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doaj-fded50f13cf740c8b09a5136a7b950a62020-11-24T21:50:21ZengMDPI AGPolymers2073-43602018-11-011011122810.3390/polym10111228polym10111228Mapping Dithiobenzoate-Mediated RAFT Polymerization Products via Online Microreactor/Mass Spectrometry MonitoringJoris J. Haven0Tanja Junkers1Polymer Reaction Design Group, School of Chemistry, Monash University, 19 Rainforest Walk, Clayton, VIC 3800, AustraliaPolymer Reaction Design Group, School of Chemistry, Monash University, 19 Rainforest Walk, Clayton, VIC 3800, Australia2-cyano-2-propyl dithiobenzoates (CPDB)-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization was monitored by online flow microreactor/mass spectrometry. This enabled the reactions to be followed in a time-resolved manner, closely resolving product patterns in the reaction mixtures at any point in time. RAFT polymerization was investigated for low RAFT to monomer ratios, enabling the monitoring of the early stages of a typical RAFT polymerization. The expected transition from pre- to the RAFT main equilibrium is observed. However, very high abundancies for cross-termination products were also identified, both in the pre- and main equilibrium stage. This is a somewhat surprising result as such products have always been expected, but to date have not been observed in the majority of studies. Product isolation and NMR analysis revealed that cross-termination occurs in the para position of the benzoate ring and becomes fully irreversible via re-aromatization of the ring in a H-shift reaction. The present data suggest a pronounced chain-length dependence of the cross-termination reaction, which would explain why the products are seen here, but not in other studies.https://www.mdpi.com/2073-4360/10/11/1228online monitoringflow polymerizationsdithiobenzoate-mediated RAFT polymerizationmass spectrometrycross-termination |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Joris J. Haven Tanja Junkers |
spellingShingle |
Joris J. Haven Tanja Junkers Mapping Dithiobenzoate-Mediated RAFT Polymerization Products via Online Microreactor/Mass Spectrometry Monitoring Polymers online monitoring flow polymerizations dithiobenzoate-mediated RAFT polymerization mass spectrometry cross-termination |
author_facet |
Joris J. Haven Tanja Junkers |
author_sort |
Joris J. Haven |
title |
Mapping Dithiobenzoate-Mediated RAFT Polymerization Products via Online Microreactor/Mass Spectrometry Monitoring |
title_short |
Mapping Dithiobenzoate-Mediated RAFT Polymerization Products via Online Microreactor/Mass Spectrometry Monitoring |
title_full |
Mapping Dithiobenzoate-Mediated RAFT Polymerization Products via Online Microreactor/Mass Spectrometry Monitoring |
title_fullStr |
Mapping Dithiobenzoate-Mediated RAFT Polymerization Products via Online Microreactor/Mass Spectrometry Monitoring |
title_full_unstemmed |
Mapping Dithiobenzoate-Mediated RAFT Polymerization Products via Online Microreactor/Mass Spectrometry Monitoring |
title_sort |
mapping dithiobenzoate-mediated raft polymerization products via online microreactor/mass spectrometry monitoring |
publisher |
MDPI AG |
series |
Polymers |
issn |
2073-4360 |
publishDate |
2018-11-01 |
description |
2-cyano-2-propyl dithiobenzoates (CPDB)-mediated reversible addition-fragmentation chain transfer (RAFT) polymerization was monitored by online flow microreactor/mass spectrometry. This enabled the reactions to be followed in a time-resolved manner, closely resolving product patterns in the reaction mixtures at any point in time. RAFT polymerization was investigated for low RAFT to monomer ratios, enabling the monitoring of the early stages of a typical RAFT polymerization. The expected transition from pre- to the RAFT main equilibrium is observed. However, very high abundancies for cross-termination products were also identified, both in the pre- and main equilibrium stage. This is a somewhat surprising result as such products have always been expected, but to date have not been observed in the majority of studies. Product isolation and NMR analysis revealed that cross-termination occurs in the para position of the benzoate ring and becomes fully irreversible via re-aromatization of the ring in a H-shift reaction. The present data suggest a pronounced chain-length dependence of the cross-termination reaction, which would explain why the products are seen here, but not in other studies. |
topic |
online monitoring flow polymerizations dithiobenzoate-mediated RAFT polymerization mass spectrometry cross-termination |
url |
https://www.mdpi.com/2073-4360/10/11/1228 |
work_keys_str_mv |
AT jorisjhaven mappingdithiobenzoatemediatedraftpolymerizationproductsviaonlinemicroreactormassspectrometrymonitoring AT tanjajunkers mappingdithiobenzoatemediatedraftpolymerizationproductsviaonlinemicroreactormassspectrometrymonitoring |
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1725884594261065728 |