Publications
173 results found
Schrecker L, Dickhaut J, Holtze C, et al., 2022, Discovery of unexpectedly complex reaction pathways for the Knorr pyrazole synthesis via transient flow, REACTION CHEMISTRY & ENGINEERING, Vol: 8, Pages: 41-46, ISSN: 2058-9883
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- Citations: 1
Li AY, Pedersen A, Feng J, et al., 2022, From haemoglobin to single-site hydrogenation catalyst, GREEN CHEMISTRY, Vol: 24, Pages: 7574-7583, ISSN: 1463-9262
Stark RT, Pye D, Chen W, et al., 2022, Assessing a sustainable manufacturing route to lapatinib, Reaction Chemistry and Engineering, Vol: 7, Pages: 2420-2426, ISSN: 2058-9883
A synthetic route to an anti-cancer drug, lapatinib, was devised to support the development of a sustainable manufacturing process in South Africa. Quantitative metrics were employed to evaluate the sustainability of the key steps of the reaction.
Colberg J, Hii KKM, Koenig SG, 2022, Importance of green and sustainable chemistry in the chemical industry a joint virtual issue between ACS sustainable chemistry & engineering and organic process research & development, Organic Process Research and Development, ISSN: 1083-6160
Colberg J, Hii KKM, Koenig SG, 2022, Importance of Green and Sustainable Chemistry in the Chemical Industry A joint virtual issue between ACS Sustainable Chemistry & Engineering and Organic Process Research & Development, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, ISSN: 2168-0485
Deadman BJ, Gian S, Lee VEY, et al., 2022, On-demand, in situ, generation of ammonium caroate (peroxymonosulfate) for the dihydroxylation of alkenes to vicinal diols, Green Chemistry, Vol: 24, Pages: 5570-5578, ISSN: 1463-9262
Using the dihydroxylation of alkenes as a benchmark, the reactivities of fresh and aged solutions of (NH4)2S2O8 (electrochemically generated) were compared to commercially-procured peroxydisulfate and Oxone®. The study revealed that peroxymonosulfate (Caro’s acid, PMS) is the active oxidant in such reactions. Using complementary redox colorimetry and in situ IR spectroscopy to monitor the oxidants, the competitive decomposition of peroxydisulfate in an acidic solution into PMS and H2O2 can be quantified for the first time. The new insight enabled the design and implementation of both batch and flow processes to maximise the concentration of active PMS oxidant. The utility of these oxidants for organic synthesis is demonstrated by the dihydroxylation of eight styrenes and seven alkyl alkenes, where the ammonium PMS solutions performed better than Oxone® (counterion effect). Last but not least, a non-chromatographic method for isolating and purifying the water-soluble diol product was developed.
Cannon AS, Carrier DJ, Engelberth AS, et al., 2022, Women in Green Chemistry and Engineering: Agents of Change Toward the Achievement of a Sustainable Future, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 10, Pages: 2859-2862, ISSN: 2168-0485
Allen DT, Licence P, Subramaniam B, et al., 2022, Building Pathways to a Sustainable Planet, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 10, Pages: 1-2, ISSN: 2168-0485
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- Citations: 1
Allen DT, Carrier DJ, Chen J, et al., 2021, Expectations for Perspectives in ACS Sustainable Chemistry & Engineering, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 9, Pages: 16528-16530, ISSN: 2168-0485
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- Citations: 1
Wang S, Panayides J-L, Riley D, et al., 2021, Rapid formation of 2-lithio-1-(triphenylmethyl)imidazole and substitution reactions in flow, Reaction Chemistry and Engineering, Vol: 6, Pages: 2018-2023, ISSN: 2058-9883
The functionalisation of imidazoles is a necessary step in the formation of many active pharmaceutical intermediates. Herein, we report a flow chemistry approach for the rapid and efficient formation of 2-lithio-1-(triphenylmethyl)imidazole at ambient temperature and its reaction with a range of electrophiles, achieving modest to high yields (40–94%) in short reaction times (<1 min). The method is amenable to the scale-up of this highly reactive lithio-imidazole intermediate.
Debecker DP, Hii KKM, Moores A, et al., 2021, Shaping Effective Practices for Incorporating Sustainability Assessment in Manuscripts Submitted to ACS Sustainable Chemistry & Engineering: Catalysis and Catalytic Processes, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 9, Pages: 4936-4940, ISSN: 2168-0485
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- Citations: 22
Subramaniam B, Allen D, Hii KKM, et al., 2021, Lab to Market: Where the Rubber Meets the Road for Sustainable Chemical Technologies, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 9, Pages: 2987-2989, ISSN: 2168-0485
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- Citations: 1
Allen DT, Carrier DJ, Chen J, et al., 2020, Remembering Professor, Academician, and Editor Lina Zhang, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 8, Pages: 16385-16385, ISSN: 2168-0485
Allen DT, Carrier J, Chen J, et al., 2020, Expectations for Manuscripts in ACS Sustainable Chemistry & Engineering: Scope Summary and Call for Creativity, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 8, Pages: 16046-16047, ISSN: 2168-0485
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- Citations: 1
Allen DT, Carrier DJ, Chen J, et al., 2020, The Changing Structure of Scientific Communication: Expanding the Nature of Letters Submissions to ACS Sustainable Chemistry & Engineering, ACS SUSTAINABLE CHEMISTRY & ENGINEERING, Vol: 8, Pages: 8469-8470, ISSN: 2168-0485
Hii KK, Mulligan C, Parker J, 2020, Revisiting the mechanism of the Fujiwara-Moritani reaction, Reaction Chemistry and Engineering, Vol: 5, Pages: 1104-1111, ISSN: 2058-9883
The Fujiwara–Moritani reaction between p-methylacetanilide and n-butyl acrylate, catalysed by Pd(OAc)2 in the presence of toluenesulfonic acid and benzoquinone, was (re-)investigated using reaction calorimetry and complementary spectroscopic methods. The (most) active catalyst was identified and the catalytic turnover rate was found to be independent of all stoichiometric reagents. Catalyst regeneration and deactivation pathways are discussed.
Hii KKM, Moores A, Pradeep T, et al., 2020, Expectations for manuscripts on catalysis in ACS sustainable chemistry & engineering, ACS Sustainable Chemistry and Engineering, Vol: 8, Pages: 4995-4996, ISSN: 2168-0485
Checchia S, Mulligan CJ, Emerich H, et al., 2020, Pd-LaFeO3 catalysts in aqueous ethanol: Pd reduction, leaching, and structural transformations in the presence of a base, ACS Catalysis, Vol: 10, Pages: 3933-3944, ISSN: 2155-5435
The reactive behavior of three catalysts based on Pd-loaded LaFeO3 was investigated in terms of the reducibility of Pd and its propensity to leaching into the liquid phase in flowing solutions prototypical of C–C coupling catalysis in a continuous flow reactor cell. In situ quick extended X-ray absorption fine structure spectroscopy showed that Pd remains stable and nonreducible in the flowing ethanol/water solvent mixture under heating to 353 K. However, ex situ transmission electron microscopy, high-energy X-ray diffraction, and fluorescence yield Fe K-edge X-ray absorption near-edge structure show that the addition of a significant amount of base (K2CO3, 0.1 M) results in the structural degradation of the perovskite support as well as the mobilization of Pd along the sample bed that is dependent on the structure and crystallite size of the perovskite. The results are discussed in terms of the use of perovskite-type oxides in various areas of research where they are placed in contact with liquid phases of variable temperature and elevated pH.
Allen DT, Carrier DJ, Chen J, et al., 2020, The evolution of ACS sustainable chemistry & engineering, ACS Sustainable Chemistry and Engineering, Vol: 8, Pages: 1-1, ISSN: 2168-0485
Newton M, Ferri D, Mulligan C, et al., 2019, In situ study of metal leaching from Pd/Al2O3 induced by K2CO3, Catalysis Science and Technology, Vol: 10, Pages: 466-474, ISSN: 2044-4753
In situ time- and spatially-resolved Quick Extended X-ray Absorption Fine Structure Spectroscopy (QEXAFS) was deployed to study the leaching of Pd from a heterogeneous catalyst caused by K2CO3 temporally and spatially.
Bourne RA, Hii KKM, Reizman BJ, 2019, Introduction to Synthesis 4.0: towards an internet of chemistry, REACTION CHEMISTRY & ENGINEERING, Vol: 4, Pages: 1504-1505, ISSN: 2058-9883
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- Citations: 7
Mulligan C, Bagale S, Newton O, et al., 2019, Peracetic acid: An atom-economical reagent for Pd-catalyzed acetoxylation of C-H bonds, ACS Sustainable Chemistry and Engineering, Vol: 7, Pages: 1611-1615, ISSN: 2168-0485
Peracetic acid can be used universally as a source of acetate and an oxidant for the selective acetoxylation of C–H bonds in compounds containing ortho-directing groups, catalyzed by Pd(OAc)2. Compared to previous procedures, where persulfates and PhI(OAc)2 were used, the new protocol provides significant improvements in atom efficiency, product yield, substrate scope, cost, scalability, and environmental impact.
Wong VHL, Hii KK, 2018, 3 Silver-Catalyzed Cyclizations, Silver Catalysis in Organic Synthesis, Pages: 85-181, ISBN: 9783527342815
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- Citations: 1
Roberts F, Richard C, Zemichael F, et al., 2018, Base-free, tunable, Au-catalyzed oxidative esterification of alcohols in continuous flow, Reaction Chemistry and Engineering, Vol: 3, Pages: 942-948, ISSN: 2058-9883
Under continuous flow conditions, hydrogen peroxide oxidizes primary alcohols (cinnamyl alcohol, decenol, decanol and benzyl alcohol) in methanol over Au/TiO2, without the need for added base. While the allylic alcohols afforded conjugated aldehydes, aliphatic and benzylic alcohols afforded acids or esters. Selectivity for either product can be achieved by adjusting the reaction parameters. Kinetic studies revealed that the formation of the easter is faster than that of the acid, due to a greater pre-organization (larger ln A) attributed to the more favourable formation of the hemiacetal intermediate.
Hii KM, hellgardt, barreiro, et al., 2018, Spatial, temporal and quantitative assessment of catalyst leaching in continuous flow, Catalysis Today, Vol: 308, Pages: 64-70, ISSN: 0920-5861
Catalyst leaching is a major impediment to the development of commercially-viable processes conducted in a liquid-phase. To date, there is no reliable technique that can accurately identify the extent and dynamics of the leaching process in a quantitative manner. In this work, a tandem flow-reactor system has been developed, which allowed us to distinguish between surface-catalyzed reactions from those occurring in solution by comparing%conversion at the exit of each reactor (S1, S2) corresponding to predominance of heterogeneous/homogeneous reactions (spatial) and two different residence times (temporal). A multiscale model is subsequently established to quantify the two types of reaction rate and simulate the catalyst leaching from a cross-coupling catalyst, PdEncat™ 30; including: (1) a multi-particle sizes model for catalyst scale; and (2) a dispersion model for reactor scale. The results show that catalyst leaching occurs via more than one process, and that the homogeneous Pd-catalyst (leached from the immobilized catalyst and dissolved in the flow) dominates the reaction and possesses a much higher activity than the heterogeneous (immobilized) Pd-catalyst. Additionally, the change of leached Pd stream inside reactors can be predicted along with the axial direction and the reaction time through the reactor-scale dispersion model.
Bystron T, Horbenko A, Syslova K, et al., 2018, 2-Iodoxybenzoic acid synthesis by oxidation of 2-Iodobenzoic acid at a Boron-doped diamond anode, ChemElectroChem, Vol: 5, Pages: 1002-1005, ISSN: 2196-0216
For the first time, the electrochemical synthesis of 2-iodoxybenzoic acid (IBX), a benign, well-established, popular and highly selective oxidising agent, is described. The objective of the work was to investigate the possibility of generating IBX electrochemically in aqueous solutions by using boron-doped diamond anodes. In 0.2 M H2SO4 aqueous solution, 2-iodobenzoic acid (IBA) was found to be oxidised at potentials >1.6 V vs. SCE, initially to 2-iodosobenzoic acid (IsBA), which was oxidised to IBX at potentials >1.8 V vs. SCE. Reductions of IBX to IsBA and IsBA to IBA occurred at similar potentials of ca. −0.7 V vs. SCE. The voltammetry results were confirmed by performing a series of batch electrolyses at different electrode potentials. Thus, depending on the electrode potential chosen, IBA can be oxidised anodically either to IsBA or IBX with 100 % overall selectivity. The only side-reaction was O2 generation, but charge yields did not decrease below 55 % even at conversions >95 %.
Keung Leung AY, Hellgardt K, Leung A, et al., 2018, Catalysis in flow: nickel-catalyzed synthesis of primary amines from alcohols and NH3, ACS Sustainable Chemistry and Engineering, Vol: 6, Pages: 5479-5484, ISSN: 2168-0485
A highly selective synthesis of primary amines from alcohols and NH3 was achieved on using a commercially available Ni catalyst, without adding H2. Using a continuous flow reaction platform, the amination of aliphatic alcohols can be achieved in good yields and selectivities, as the accumulation of water byproduct can be removed. Competitive formation of the nitrile side-product was suppressed when the catalyst was prereduced. Modes of catalyst deactivation were also briefly examined.
Luo M, Zhang JC, Pang WM, et al., 2017, Erratum to: One-step multicomponent synthesis of chiral oxazolinyl-zinc complexes, Chemistry Central Journal, Vol: 11, ISSN: 1752-153X
Luo M, Zhang JC, Pang WM, et al., 2017, One-step multicomponent synthesis of chiral oxazolinyl-zinc complexes, CHEMISTRY CENTRAL JOURNAL, Vol: 11, ISSN: 1752-153X
BackgroundTypically, oxazolinyl metal complexes are synthesized in two steps, where the free ligand is prepared by the condensation reaction between a functionalized nitrile and an amino alcohol in the presence of a Lewis or Brønsted acid catalyst, followed by a further reaction with metal salts to obtain the corresponding metal complexes. Very often, the yield afforded by the two-step procedure is not high, and very few oxazolinyl zinc complexes have been prepared by this route. Given that metal-oxazoline complexes often contain Lewis acidic metals, it is conceivable that the two steps may be telescoped.ResultsA series of novel chiral organozinc complexes 1–15 were assembled in a single step, All crystalline compounds were fully characterized, including the report of 15 X-ray crystal structures, including a wide structural diversity.ConclusionsA series of novel chiral organozinc complexes were assembled in a single step, from nitriles, chiral D/L amino alcohols, and a stoichiometric amount of ZnCl2, with moderate to high yields (20–90%).
Hii KM, Newton MA, Nicholls R, et al., 2017, Effect of retained chlorine in ENCAT™ 30 catalysts on the development of encapsulated Pd: insights from in situ Pd K, L3 and Cl K-edge XAS, Catalysis, Structure & Reactivity, Vol: 3, Pages: 149-156, ISSN: 2055-074X
In situ X-ray absorption spectroscopy (XAS) and Pd K, LIII, and Cl K-edges shows that Cl can be present in significant amounts in ENCAT™ 30 catalysts and that it can severely retard Pd nanoparticle (NP) development in flowing solvents. We also show that whilst polymeric encapsulation protects the Pd against solvent induced agglomeration of Pd nanoparticles the evidence suggests it does not prevent the formation PdHx through reaction with the aqeous ethanol solvent, and that, as received, ENCAT™ 30 NP catalysts are not, for the most part, comprised of nanoparticulate Pd0 irrespective of the presence of Cl.
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