The metal-free polymerization of propylene oxide (PO) using a special class of alkene—N-heterocyclic olefins (NHOs)—as catalysts is described. Manipulation of the chemical structure of the NHO organocatalyst allows for the preparation of the poly(propylene oxide) in high yields with high turnover (TON>2000), which renders this the most active metal-free system for the polymerization of PO reported to date. The resulting polyether displays predictable end groups, molar mass, and a low dispersity (Đ(M)<1.09). NHOs with an unsaturated backbone are essential for polymerization to occur, while substitution at the exocyclic carbon atom has an impact on the reaction pathway and ensures the suppression of side reactions.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4539597 | PMC |
| http://dx.doi.org/10.1002/anie.201504175 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Microplastics in rivers of Gujarat (India) until the Arabian Sea: assessment of the sources, distribution and associated environmental risk.
Integr Environ Assess Manag
January 2025
Mu Gamma Consultants Pvt. Ltd, Gurgaon, India, 122018.
Microplastics (MPs) have become a notable concern and are released into the environment through the disposal or fragmentation of large plastics. Rivers have been the major pathways for MPs present in the oceans, which significantly affects the marine environment. In the current study, water samples were collected from the upper stream and downstream of Damanganga and Tapi rivers across different sites in the state of Gujarat, India for exploration of MPs contamination.
View Article and Find Full Text PDFInvestigating the interactions between a poloxamer and TEMPO-oxidised cellulose nanocrystals.
Carbohydr Polym
March 2025
Bristol Composites Institute, School of Civil, Aerospace, and Design Engineering, University of Bristol, University Walk, Bristol BS8 1TR, UK. Electronic address:
Cellulose nanocrystals (CNCs) have emerged as promising, sustainable materials, with applications in sensors, coatings, pharmaceuticals, and composites. Their modification with block copolymers such as PEO-PPO-PEO triblock copolymers of the Pluronic family has been attempted many times in the literature, with claims that such modification would happen by an anchor(PEO)-buoy(PPO)-anchor(PEO) mechanism. However, there is much disagreement in the literature on this.
View Article and Find Full Text PDFAcidity Reversal Enables Site-Specific Ring-Opening Polymerization of Epoxides from Biprotonic Compounds.
J Am Chem Soc
January 2025
Department of Polymer Chemistry and Technology, National Institute of Chemistry, Hajdrihova 19, 1000 Ljubljana, Slovenia.
Polyethers are versatile materials extensively used in advanced as well as everyday applications. The incorporation of primary amine functionality into polyethers is particularly attractive due to its well-established coupling chemistries. However, the inherent nucleophilicity of amine group poses a challenge in the anionic ring-opening polymerization (ROP) of epoxides and requires the use of robust protecting groups that can withstand the harsh conditions of ROP without triggering undesirable side reactions.
View Article and Find Full Text PDFRaman and ATR-FTIR unmask crystallinity changes and carboxylate group and vinyl group accumulation in natural weathering polypropylene microplastics.
Sci Rep
January 2025
Department of Biomedical Sciences, Graduate School of Science and Technology, Kwansei Gakuin University, Gakuen-Uegahara, Sanda, Hyogo, 669-1330, Japan.
Naturally weathered polypropylene (NWPP) samples are useful for investigating the effects of various degradation factors that cannot be obtained in artificial laboratory experiments. In this study, NWPP samples were extracted from beach sediments (Ashiya, Hyogo, Japan). Raman and attenuated total reflection (ATR)-Fourier-transform infrared (FTIR) spectroscopies were used to analyze variations in the composition, crystallinity, orientation, and degradation of NWPP microplastics.
View Article and Find Full Text PDFAdsorption behavior of Cu(II) on UV-aged polyethylene terephthalate and polypropylene microplastics in aqueous solution.
Environ Sci Pollut Res Int
January 2025
Department of Civil Engineering, National Institute of Technology Andhra Pradesh, Tadepalligudem, India.
Plastics are widely used across various applications from packing to commercial products. Once discarded, they were subjected to environmental stresses, causing them to degrade into microplastics (MPs). These small, invisible pollutants pose a significant threat to aquatic ecosystems, gradually compromising the resilience and vitality of the natural environment.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!