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Publications (10 of 25) Show all publications
Franzen, J., Infantes, E. & Gröndahl, F. (2019). Beach-cast as biofertiliser in the Baltic Sea region-potential limitations due to cadmium-content. Ocean and Coastal Management, 169, 20-26
Open this publication in new window or tab >>Beach-cast as biofertiliser in the Baltic Sea region-potential limitations due to cadmium-content
2019 (English)In: Ocean and Coastal Management, ISSN 0964-5691, E-ISSN 1873-524X, Vol. 169, p. 20-26Article in journal (Refereed) Published
Abstract [en]

Macroalgal mass blooms and accumulating beach-cast are increasing problems in many coastal areas. However, beach-cast is also a potentially valuable marine bioresource, e.g. as a biofertiliser in coastal agriculture. One limiting factor in use of beach-cast as a fertiliser is uncertainty regarding the cadmium (Cd) concentration depending on beach-cast composition and location. In this study, chemical analyses were performed on beach cast from Burgsviken Bay off Gotland, in the Baltic Sea. The results revealed large variations in cadmium concentration depending on sampling location and beach-cast composition, with levels ranging between 0.13 and 2.2 mg Cd/kg dry matter (DM). Of 15 beach-cast samples analysed, one had a cadmium content above the Swedish statutory limit for sewage sludge biofertiliser (2 mg Cd/kg DM) and four had values above the limit suggested by the Swedish Environmental Protection Agency for 2030 (0.8 mg/kg DM). Species-specific analysis revealed that eelgrass (Zostera marina) contained significantly higher cadmium concentrations than filamentous red algae species (Ceramium and Polysiphonia spp.). Avoiding eelgrass-rich beach-cast by seasonal timing of harvesting and monitoring differences in cadmium concentrations between harvesting sites could thus facilitate use of beach-cast as biofertiliser.

Place, publisher, year, edition, pages
ELSEVIER SCI LTD, 2019
Keywords
Beach-cast management, Macro algae, Seagrass, Zostera marina, Marine bioresources, Cadmium-levels, Biofertiliser, Species composition
National Category
Environmental Management
Identifiers
urn:nbn:se:kth:diva-246247 (URN)10.1016/j.ocecoaman.2018.11.015 (DOI)000459518700003 ()2-s2.0-85058051876 (Scopus ID)
Note

QC 20190403

Available from: 2019-04-03 Created: 2019-04-03 Last updated: 2019-04-04Bibliographically approved
Hua, G., Franzén, J. & Odelius, K. (2019). Phosphazene-Catalyzed Regioselective Ring-Opening Polymerization of rac-1-Methyl Trimethylene Carbonate: Colder and Less is Better. Macromolecules, 52(7), 2681-2690
Open this publication in new window or tab >>Phosphazene-Catalyzed Regioselective Ring-Opening Polymerization of rac-1-Methyl Trimethylene Carbonate: Colder and Less is Better
2019 (English)In: Macromolecules, ISSN 0024-9297, E-ISSN 1520-5835, Vol. 52, no 7, p. 2681-2690Article in journal (Refereed) Published
Abstract [en]

The regioselective organocatalytic ring-opening polymerization (ROP) of a 6-membered cyclic carbonate, rac-1-methyl trimethylene carbonate, was studied using phosphazene base (t-BuP2) as the principle catalyst. The influence on the reaction kinetics caused by the reaction temperature (-74-60 degrees C), catalyst loading (0.5-2.5%), and reaction solvent (toluene and tetrahydrofuran) was systematically tuned and followed by H-1 NMR. All studied reactions reached close to or above 90% monomer conversion in 3 h, and all exhibited typical equilibrium polymerization behavior that is inherent to 6-membered cyclic carbonates. Good control over the molecular weight and distribution of the polycarbonate product was obtained in most studied conditions, with M-n ranging from similar to 4k to similar to 20k and D < 1.2. The regioregularity (X-reg) of the resulting polycarbonate was thoroughly studied using various NMR techniques, with the highest X-reg obtained being.0.90. The major influence from the reaction conditions on both the ROP kinetics and X-reg are as follows: higher reaction temperature resulted in a decrease of both; higher catalyst loading resulted in a faster ROP reaction but a slight decrease in X-reg; and toluene being a better solvent resulted in both faster reaction and higher X-reg. Throughout this study, we have demonstrated the possibility to synthesize regioregular aliphatic polycarbonate using an organic base as the ROP catalyst, contrary to the existing studies on similar systems where only metal-base catalysts were in focus and our systems showed similar high X-reg of the product.

Place, publisher, year, edition, pages
AMER CHEMICAL SOC, 2019
National Category
Polymer Chemistry
Identifiers
urn:nbn:se:kth:diva-251201 (URN)10.1021/acs.macromol.8b02591 (DOI)000464475900007 ()2-s2.0-85064209906 (Scopus ID)
Note

QC 20190724

Available from: 2019-07-24 Created: 2019-07-24 Last updated: 2019-07-24Bibliographically approved
Ni, S. & Franzén, J. (2018). Carbocation catalysed ring closing aldehyde-olefin metathesis. Chemical Communications, 54(92), 12982-12985
Open this publication in new window or tab >>Carbocation catalysed ring closing aldehyde-olefin metathesis
2018 (English)In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 54, no 92, p. 12982-12985Article in journal (Refereed) Published
Abstract [en]

A highly efficient aldehyde-olefin metathesis catalysed by the carbocation, 4-phenylphenyl-diphenylmethylium ion, has been developed. This protocol is characterized by high yields, low catalyst loading (down to 2 mol%), good functional group compatibility and mild reaction conditions.

Place, publisher, year, edition, pages
ROYAL SOC CHEMISTRY, 2018
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-239759 (URN)10.1039/c8cc06734a (DOI)000450435700016 ()30383876 (PubMedID)2-s2.0-85056554772 (Scopus ID)
Note

QC 20190110

Available from: 2019-01-10 Created: 2019-01-10 Last updated: 2019-01-10Bibliographically approved
Timmer, B., Schaufelberger, F., Hammarberg, D., Franzen, J., Ramström, O. & Dinér, P. (2018). Simple and Effective Integration of Green Chemistry and Sustainability Education into an Existing Organic Chemistry Course. Journal of Chemical Education, 95(8), 1301-1306
Open this publication in new window or tab >>Simple and Effective Integration of Green Chemistry and Sustainability Education into an Existing Organic Chemistry Course
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2018 (English)In: Journal of Chemical Education, ISSN 0021-9584, E-ISSN 1938-1328, Vol. 95, no 8, p. 1301-1306Article in journal (Refereed) Published
Abstract [en]

Green chemistry and sustainable development have become increasingly important topics for the education of future chemists. The cross-disciplinary nature of green chemistry and sustainable development often means these subjects are taught in conjunction with other subjects, such as organic chemistry and chemical engineering. Herein, a straightforward and efficient approach for vertical integration of green chemistry concepts within existing undergraduate organic chemistry courses is shown. The gradual self-evaluation, "greenification", and reassessment of an organic chemistry course at KTH Royal Institute of Technology from 2013 to 2017 is described, with particular focus on the laboratory course and a novel green chemistry project designed to promote sustainability thinking and reasoning. The laboratory project, which can also be conducted as an independent organic chemistry laboratory exercise, required students to critically evaluate variations of the same Pechmann condensation experiment according to the twelve principles of green chemistry. The course evaluation shows that, after the modifications, students feel more comfortable with the topics "green chemistry" and "sustainability" and consider these topics more important for their future careers. Furthermore, the ability of students to discuss and critically evaluate green chemistry parameters improved considerably as determined from the laboratory project reports.

Place, publisher, year, edition, pages
American Chemical Society (ACS), 2018
Keywords
Second-Year Undergraduate, Organic Chemistry, Problem Solving/Decision Making, Testing/Assessment, Green Chemistry, Reactions
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-240202 (URN)10.1021/acs.jchemed.7b00720 (DOI)000442961800008 ()2-s2.0-85051517648 (Scopus ID)
Note

QC 20181217

Available from: 2018-12-17 Created: 2018-12-17 Last updated: 2018-12-17Bibliographically approved
Hua, G., Johan, F. & Odelius, K. (2016). One-pot inimer promoted ROCP synthesis of branched copolyesters using α-hydroxy-γ-butyrolactone as the branching reagent. Journal of Polymer Science Part A: Polymer Chemistry, 54(13), 1908-1918
Open this publication in new window or tab >>One-pot inimer promoted ROCP synthesis of branched copolyesters using α-hydroxy-γ-butyrolactone as the branching reagent
2016 (English)In: Journal of Polymer Science Part A: Polymer Chemistry, ISSN 0887-624X, E-ISSN 1099-0518, Vol. 54, no 13, p. 1908-1918Article in journal (Refereed) Published
Abstract [en]

An array of branched poly(ɛ-caprolactone)s was successfully synthesized using an one-pot inimer promoted ring-opening multibranching copolymerization (ROCP) reaction. The biorenewable, commercially available yet unexploited comonomer and initiator 2-hydroxy-γ-butyrolactone was chosen as the inimer to extend the use of 5-membered lactones to branched structures and simultaneously avoiding the typical tedious work involved in the inimer preparation. Reactions were carried out both in bulk and in solution using stannous octoate (Sn(Oct)2) as the catalyst. Polymerizations with inimer equivalents varying from 0.01 to 0.2 were conducted which resulted in polymers with a degree of branching ranging from 0.049 to 0.124. Detailed ROCP kinetics of different inimer systems were compared to illustrate the branch formation mechanism. The resulting polymer structures were confirmed by 1H, 13C, and 1H-13C HSQC NMR and SEC (RI detector and triple detectors). The thermal properties of polymers with different degree of branching were investigated by DSC, confirming the branch formation. Through this work, we have extended the current use of the non-homopolymerizable γ-butyrolactone to the branched polymers and thoroughly examined its behaviors in ROCP.

Place, publisher, year, edition, pages
John Wiley & Sons, 2016
National Category
Textile, Rubber and Polymeric Materials
Identifiers
urn:nbn:se:kth:diva-182202 (URN)10.1002/pola.28048 (DOI)000380038000004 ()2-s2.0-84958280950 (Scopus ID)
Note

QC 20160613

Available from: 2016-02-17 Created: 2016-02-17 Last updated: 2017-11-30Bibliographically approved
El Remaily, M. A., Naidu, V. R., Ni, S. & Franzén, J. (2015). Carbocation Catalysis: Oxa-Diels-Alder Reactions of Unactivated Aldehydes and Simple Dienes. European Journal of Organic Chemistry (30), 6610-6614
Open this publication in new window or tab >>Carbocation Catalysis: Oxa-Diels-Alder Reactions of Unactivated Aldehydes and Simple Dienes
2015 (English)In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 30, p. 6610-6614Article in journal (Refereed) Published
Abstract [en]

The versatility of the trityl cation (TrBF<inf>4</inf>) as a highly efficient Lewis acid organocatalyst is demonstrated in the oxa-Diels-Alder reaction of various unactivated aromatic and aliphatic aldehydes and simple unactivated dienes, such as isoprene and 2,3-dimethylbutadiene. The transformation proceeds smoothly to give 3,6-dihydropyrane adducts in high to moderate yields with catalyst loadings down to 1.0 mol-% under mild reaction conditions. In contrast to most previously reported strategies, this protocol does not require substrate functional group activation, neither by electron-deficient aldehydes (2-oxo aldehydes) or electron-rich dienes (methoxy or amino-butadiene).

Place, publisher, year, edition, pages
Wiley-VCH Verlagsgesellschaft, 2015
Keywords
Carbocations, Cycloaddition, Organocatalysis, Trityl ion
National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-175061 (URN)10.1002/ejoc.201501112 (DOI)000363339600005 ()2-s2.0-84945478847 (Scopus ID)
Note

QC 20151211

Available from: 2015-12-11 Created: 2015-10-09 Last updated: 2018-09-26Bibliographically approved
Naidu, V. R., Bah, J. & Franzén, J. (2015). Direct Organocatalytic Oxo-Metathesis, a trans-Selective Carbocation-Catalyzed Olefination of Aldehydes. European Journal of Organic Chemistry (8), 1834-1839
Open this publication in new window or tab >>Direct Organocatalytic Oxo-Metathesis, a trans-Selective Carbocation-Catalyzed Olefination of Aldehydes
2015 (English)In: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, no 8, p. 1834-1839Article in journal (Refereed) Published
Abstract [en]

A direct organocatalytic carbonyl/olefin oxo-metathesis has been developed. The reaction is catalyzed by trityl tetrafluoroborate (TrBF4) and utilizes unactivated alkenes for the olefination of aromatic aldehydes to give trans -alkylstyrenes in yields of 44-85% with only acetone as the byproduct. The pronounced Lewis acidity of the carbocation results in unusual reactivity that is proposed to catalyze a stepwise [2+2] cycloaddition to give an oxetane intermediate. Fragmentation of the latter in a formal retro [2+2] reaction gives the oxo-metathesis product.

National Category
Organic Chemistry
Identifiers
urn:nbn:se:kth:diva-164466 (URN)10.1002/ejoc.201403651 (DOI)000351054500025 ()
Funder
Swedish Research Council
Note

QC 20150422

Available from: 2015-04-22 Created: 2015-04-17 Last updated: 2017-12-04Bibliographically approved
Naidu, V. R., Ni, S. & Franzén, J. (2015). The Carbocation: A Forgotten Lewis Acid Catalyst. ChemCatChem, 7(13), 1896-1905
Open this publication in new window or tab >>The Carbocation: A Forgotten Lewis Acid Catalyst
2015 (English)In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 7, no 13, p. 1896-1905Article in journal (Refereed) Published
Abstract [en]

A Lewis acid that has received negligible attention as a catalyst is the carbocation. The carbocation is isoelectronic to boron and owes its Lewis acidity to a low-lying empty p(C) orbital. In terms of reactivity and stability carbocations are very versatile Lewis acids, from the extremely unstable methylium cation to the water-stable tris(N,N-dimethylaniline) methylium ion (crystal violet). Although the Lewis acid properties of carbocations have been extensively studied since the discovery of the tropolium ion more than 130years ago there is only a handful examples on the application of carbocations as Lewis acid catalysts. Herein, the research on triarylmethylium (trityl)-cation catalysis is summarized. In light of the reports the trityl ion emerges as a highly efficient and highly versatile Lewis acid catalyst capable of catalyzing different classes of reactions often with high selectivity and low catalyst loadings (for some reactions down to ppm levels).

Keywords
aldol reaction, carbocations, Diels-Alder reaction, Lewis acids, organocatalysis
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-172492 (URN)10.1002/cctc.201500225 (DOI)000357336400001 ()2-s2.0-84934290639 (Scopus ID)
Funder
Swedish Research CouncilWenner-Gren Foundations
Note

QC 20150825

Available from: 2015-08-25 Created: 2015-08-25 Last updated: 2017-12-04Bibliographically approved
Bah, J. & Franzén, J. (2014). Carbocations as Lewis Acid Catalysts in Diels-Alder and Michael Addition Reactions. Chemistry - A European Journal, 20(4), 1066-1072
Open this publication in new window or tab >>Carbocations as Lewis Acid Catalysts in Diels-Alder and Michael Addition Reactions
2014 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 20, no 4, p. 1066-1072Article in journal (Refereed) Published
Abstract [en]

In general, Lewis acid catalysts are metal-based compounds that owe their reactivity to a low-lying empty orbital. However, one potential Lewis acid that has received negligible attention as a catalyst is the carbocation. We have demonstrated the potential of the carbocation as a highly powerful Lewis acid catalyst for organic reactions. The stable and easily available triphenylmethyl (trityl) cation was found to be a highly efficient catalyst for the Diels-Alder reaction for a range of substrates. Catalyst loadings as low as 500ppm, excellent yields, and good endo/exo selectivities were achieved. Furthermore, by changing the electronic properties of the substituents on the tritylium ion, the Lewis acidity of the catalyst could be tuned to control the outcome of the reaction. The ability of this carbocation as a Lewis acid catalyst was also further extended to the Michael reaction.

Keywords
carbocations, catalysis, Diels-Alder reactions, Michael addition, organocatalysis, tritylium ions
National Category
Chemical Sciences
Identifiers
urn:nbn:se:kth:diva-141061 (URN)10.1002/chem.201304160 (DOI)000329548000022 ()2-s2.0-84892615130 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20140211

Available from: 2014-02-11 Created: 2014-02-07 Last updated: 2017-12-06Bibliographically approved
Fatih Polat, M., Hettmanczyk, L., Zhang, W., Szabo, Z. & Franzén, J. (2013). One-Pot, Two-Step Protocol for the Catalytic Asymmetric Synthesis of Optically Active N,O- and O,O-Acetals. ChemCatChem, 5(6), 1334-1339
Open this publication in new window or tab >>One-Pot, Two-Step Protocol for the Catalytic Asymmetric Synthesis of Optically Active N,O- and O,O-Acetals
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2013 (English)In: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 5, no 6, p. 1334-1339Article in journal (Refereed) Published
Keywords
Acetals, Asymmetric catalysis, Conjugate addition, Heterocycles, Organocatalysis
National Category
Physical Chemistry
Identifiers
urn:nbn:se:kth:diva-134274 (URN)10.1002/cctc.201200860 (DOI)000319680800017 ()2-s2.0-84878499424 (Scopus ID)
Funder
Swedish Research Council
Note

QC 20131125

Available from: 2013-11-25 Created: 2013-11-20 Last updated: 2017-05-30Bibliographically approved
Organisations
Identifiers
ORCID iD: ORCID iD iconorcid.org/0000-0003-1933-4193

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