Browsing Research Output by Author "10063552 - Vosloo, Hermanus Cornelius Moolman"
Now showing items 1-20 of 39
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Aluminum triflate-cocatalyzed radical copolymerization of styrene and ethyl acrylate
Guyo, Upenyu; Otto, Daniel P.; Young, Desmond A.; Vosloo, Hermanus C.M. (Springer, 2020)Various random copolymers, poly(styrene-co-ethyl acrylate), were synthesized by free radical bulk copolymerization cocatalyzed by aluminum triflate (Al(OTf)3). The experimental conditions for the polymerization reactions, ... -
Catalysis of linear alkene metathesis by Grubbs-type ruthenium alkylidene complexes containing hemilabile α,α-diphenyl-(monosubstituted-pyridin-2-yl)methanolato ligands
Tole, Tegene T.; Jordaan, Johan H.L.; Vosloo, Hermanus C.M. (Beilstein-Institut, 2019)Four new Grubbs-type precatalysts [RuCl(H2IMes)(O^N)(=CHPh)], where [O^N = α,α-diphenyl-(3-methylpyridin-2-yl)methanolato, α,α-diphenyl-(4-methylpyridin-2-yl)methanolato, α,α-diphenyl-(5-methylpyridin-2-yl)methanolato and ... -
Chemical oxidative polymerization of m-phenylenediamine and its derivatives using aluminium triflate as a co-catalyst
Amer, Ismael; Young, Desmond Austin; Vosloo, Hermanus C.M. (Elsevier, 2013)Aromatic diamine monomers, including m-phenylenediamine (mPD), 2-methyl-m-phenylenediamine (2Me-mPD), 4-methyl-m-phenylenediamine (4Me-mPD) and trimethyl-mphenylenediamine (tMe-mPD), were polymerized by chemical oxidation ... -
A comparison of low and high activity precatalysts: do the calculated energy barriers during the self-metathesis reaction of 1-octene correlate with the precatalyst metathesis activity?
Marx, Frans T.I.; Jordaan, Johan H.L.; Lachmann, Gerhard; Vosloo, Hermanus C.M. (Wiley, 2014)The self-metathesis reaction of 1-octene with several wellknown Grubbs-type precatalysts and the new Z-selective Grubbs precatalyst were studied with molecular modeling. The obtained Gibbs-free energy values for all the ... -
The development of a Cu(I)/pyrazolylpyridineamine catalyst system for the hydroxylation of aryl halides
Marais, Lindie; Vosloo, Hermanus C.M.; Swarts, Andrew J. (Elsevier, 2020)A catalyst system comprising of pyrazolylpyridineamine/Cu(I)/CsOH is reported. for the hydroxylation of aryl iodides and bromides with moderate to outstanding yields, without the use of an inert atmosphere. A comprehensive ... -
Development of microporous drug-releasing films cast from artificial nanosized latexes of poly (styrebe-co-methyl methacrylate) or poly (styrene-co-ethyl methacylate)
Otto, Daniel P.; Vosloo, Hermanus C.M.; Liebenberg, Wilna; De Villiers, Melgardt M. (Elsevier, 2008)Two sets of copolymers comprising of styrene and either methyl or ethyl methacrylate as comonomer were conveniently synthesized by microemulsion copolymerization. The purified materials were characterized by GPC-MALLS and ... -
A DFT computational study of phosphine ligand dissociation versus hemilability in a Grubbs-type precatalyst containing a bidentate ligand during alkene metathesis
Jordaan, M.; Vosloo, H.C.M. (Taylor & Francis, 2008)Using density functional theory, the metathesis reaction of 1-octene in the presence of a Grubbs-type ruthenium alkylidene complex bearing a chelating pyridinyl alcoholate ligand, [RuCl(L)(O∧ N)( = CHPh)] (L = H2IMes or ... -
DFT investigation of the 1-octene metathesis reaction mechanism with the Phobcat precatalyst
Marx, Frans T.I.; Vosloo, Hermanus C.M.; Jordaan, Johan H.L. (Springer, 2009)The productive self-metathesis reaction of 1-octene in the presence of the Phobcat precatalyst [RuCl2(Phoban-Cy)2(=CHPh)] using density functional theory was investigated and compared to the Grubbs 1 precatalyst ... -
Effects of the cosurfactant 1-butanol and feed composition on nanoparticle properties
Otto, Daniel P.; Vosloo, Hermanus C.M.; Liebenberg, Wilna; De Villiers, Melgardt M. (Wiley, 2008)The concentration of the cosurfactant 1-butanol (BuOH) determined the polymer weight and size for a series of poly(styrene-co-methyl methacrylate)s (P(St-co-MMA)) synthesized by the free-radical (o/w) microemulsion technique. ... -
Experimental and DFT investigation of the 1-octene metathesis reaction mechanism with the Grubbs 1 precatalyst
Jordaan, M.; Van Helden, P.; Van Sittert, C.G.C.E.; Vosloo, H.C.M. (Elsevier, 2006)Using density functional theory the metathesis reactions of 1-octene in the presence of Grubbs 1 [RuCl2(PCy3)2( CHPh)] is investigated. At the GGA-PW91/DNP level, the complete geometry optimization and the activation ... -
Experimental, DFT and kinetic study of 1-octene metathesis with Hoveyda-Grubbs second generation precatalyst
Van der Gryp, Percy; Marx, Sanette; Vosloo, Hermanus C.M. (Elsevier, 2012)In this study we report the catalytic performance, reaction engineering kinetics and elucidation of the reaction mechanism using density functional theory (DFT) for the metathesis reaction of 1-octene in the presence of ... -
Fast and efficient nickel(II)-catalysed transfer hydrogenation of quinolines with ammonia borane
Vermaak, Vincent; Vosloo, Hermanus C.M.; Swarts, Andrew J. (Wiley, 2020)Herein we report the first Ni(II)‐catalysed transfer hydrogenation of quinolines using ammonia borane (AB) as hydrogen (H2) source. An in situ generated Ni(II)‐bis(pyrazolyl)pyridine pre‐catalyst could hydrogenate quinoline ... -
Functionalising lignin in crude glycerol to prepare polyols and polyurethane
Muller, Louis Christiaan; Marx, Sanette; Vosloo, Hermanus C.M.; Chiyanzu, Idan (Sage, 2019)In this work, crude glycerol liquefaction of lignins produced in the pulp and paper industry, as well as an organosolv lignin (sugarcane bagasse), was studied with the ultimate aim of preparing biobased polyols for ... -
Geographical information system software as in-house chemical indexing database for catalyst screening of alkene metathesis catalysts
Du Toit, Jean I.; Du Toit, Marié J.; Van Sittert, Cornelia G.C.E.; Vosloo, Hermanus C.M. (Elsevier, 2020)Large amounts of chemical information can be indexed on various databases. If these databases store information in an appropriate format for specific search queries, we can perform a catalyst screening from intelligent ... -
Improved metathesis lifetime: chelating pyridinyl-alcoholato ligands in the second generation Grubbs precatalyst
Du Toit, Jean I.; Huijsmans, Carlijn A.A.; Jordaan, Johannes H.L.; Van Sittert, Cornelia G.C.E.; Vosloo, Hermanus C.M.; Jordaan, Margaritha (MDPI, 2014)Hemilabile ligands can release a free coordination site “on demand” of an incoming nucleophilic substrate while occupying it otherwise. This is believed to increase the thermal stability and activity of catalytic systems ... -
Industrial viability of homogeneous olefin metathesis: beneficiation of linear alpha olefins with the diphenyl-substituted pyridinyl alcoholato ruthenium carbene precatalyst
Du Toit, Jean I.; Loock, Monique M.; Tole, Tegene T.; Marx, Sanette; Jordaan, Johannes H.L.; Vosloo, Hermanus C.M. (Elsevier, 2016)The catalytic performance of the diphenyl-substituted pyridinyl alcoholato ruthenium carbene precatalyst of the Grubbs 2-type was optimized for 1-octene metathesis by varying operating parameters, such as reaction temperature ... -
Kinetic evaluation of the hydroformylation of the post-metathesis product 7-tetradecene using a bulky phosphite-modified rhodium catalyst
Breckwoldt, Nicholas C.C.; Vosloo, Hermanus C.M.; Van der Gryp, Percy; Goosen, Neill J. (RSC, 2019)The reaction engineering kinetics for the hydroformylation of the post-metathesis product 7-tetradecene using the bulky phosphite-modified rhodium catalyst Rh-tris(2,4-di-tertbutylphenyl)phosphite were evaluated. The ... -
Metal carbenes in homogeneous alkene metathesis: computational investigations
Du Toit, J.I.; Van Sittert, C.G.C.E.; Vosloo, H.C.M. (Elsevier, 2013)This paper demonstrates the contribution of molecular modeling as a tool to understanding alkene metathesis e by giving an overview of computational studies done of the four main types of metal carbenes tested in homogeneous ... -
Metathesis access to monocyclic iminocyclitol-based therapeutic agents
Dragutan, Ileana; Vosloo, Hermanus C.M.; Delaude, Lionel; Dragutan, Valerian; Mitan, Carmen (Beilstein-Institut, 2011)By focusing on recent developments on natural and non-natural azasugars (iminocyclitols), this review bolsters the case for the role of olefin metathesis reactions (RCM, CM) as key transformations in the multistep syntheses ... -
A molecular modeling study of the changes of some steric properties of the precatalysts during the olefin metathesis reaction
Marx, Frans T.I.; Jordaan, Johan H.L.; Lachmann, Gerhard; Vosloo, Hermanus C.M. (Wiley, 2014)The productive self-metathesis of 1-octene with a series of new phosphine ligated Grubbs-type precatalysts was studied. The resulting structures were used to compare some steric properties of the new precatalysts with ...