Imperial College London

Professor Tom Welton

Faculty of Natural SciencesDepartment of Chemistry

Professor of Sustainable Chemistry
 
 
 
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Contact

 

+44 (0)20 7594 5763t.welton Website

 
 
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Location

 

601AMolecular Sciences Research HubWhite City Campus

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Summary

 

Publications

Publication Type
Year
to

219 results found

Holloczki O, Malberg F, Welton T, Kirchner Bet al., 2014, On the origin of ionicity in ionic liquids. Ion pairing versus charge transfer, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 16, Pages: 16880-16890, ISSN: 1463-9076

Journal article

De Gregorio GF, Welton T, Hallett JP, 2014, Elucidating the mechanism of lignin depolymerisation using acidic ionic liquids: A focus on ether cleavage, 248th National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Ismail NL, Trang QT, Hallett JP, Welton Tet al., 2014, Nucleophilic substitution of benzyl alcohol with hydrogensulfate ionic liquids, 248th National Meeting of the American-Chemical-Society (ACS), Publisher: AMER CHEMICAL SOC, ISSN: 0065-7727

Conference paper

Cecchini MP, Turek VA, Demetriadou A, Britovsek G, Welton T, Kornyshev AA, Wilton-Ely JDET, Edel JBet al., 2014, Heavy Metal Sensing Using Self-Assembled Nanoparticles at a Liquid–Liquid Interface, Advanced Optical Materials

Journal article

Matthews RP, Ashworth C, Welton T, Hunt PAet al., 2014, The impact of anion electronic structure: similarities and differences in imidazolium based ionic liquids, JOURNAL OF PHYSICS-CONDENSED MATTER, Vol: 26, ISSN: 0953-8984

Journal article

Mac Dowell N, Llovell F, Sun N, Hallett JP, George A, Hunt PA, Welton T, Simmons BA, Vega LFet al., 2014, New Experimental Density Data and soft-SAFT Models of Alkylimidazolium ([CnC₁im](+)) Chloride (Cl-), Methylsulfate ([MeSO4](-)), and Dimethylphosphate ([Me2PO4](-)) Based Ionic Liquids, JOURNAL OF PHYSICAL CHEMISTRY B, Vol: 118, Pages: 6206-6221, ISSN: 1520-6106

Journal article

Chen L, Sharifzadeh M, Mac Dowell N, Welton T, Shah N, Hallett JPet al., 2014, Inexpensive ionic liquids: [HSO₄]¯-based solvent production at bulk scale, Green Chemistry, Vol: 16, Pages: 3098-3106, ISSN: 1744-1560

Through more than two decades’ intensive research, ionic liquids (ILs) have exhibited significant potential in various areas of research at laboratory scales. This suggests that ILs-based industrial process development will attract increasing attention in the future. However, there is one core issue that stands in the way of commercialisation: the high cost of most laboratory-synthesized ILs will limit application to small-scale, specialized processes. In this work, we evaluate the economic feasibility of two ILs synthesized via acid–base neutralization using two scenarios for each: conventional and intensification processing. Based upon our initial models, we determined the cost price of each IL and compared the energy requirements of each process option. The cost prices of triethylammonium hydrogen sulfate and 1-methylimidazolium hydrogen sulfate are estimated as $1.24 kg−1 and $2.96–5.88 kg−1, respectively. This compares favourably with organic solvents such as acetone or ethyl acetate, which sell for $1.30–$1.40 kg−1. Moreover, the raw materials contribute the overwhelming majority of this cost and the intensified process using a compact plate reactor is more economical due to lower energy requirements. These results indicate that ionic liquids are not necessarily expensive, and therefore large-scale IL-based processes can become a commercial reality.

Journal article

Welton T, 2014, Introducing Ionic Liquids, Supported Ionic Liquids: Fundamentals and Applications, Pages: 11-36, ISBN: 9783527324293

© 2014 Wiley-VCH Verlag GmbH & Co. KGaA. All rights reserved. This chapter summarizes the known physicochemical properties that are of particular interest for supported ionic liquid phases (SILPs). Any salt that is sufficiently thermally stable will form an ionic liquid when it melts. The most important property of an ionic liquid is whether it is a liquid or not in the required temperature range. Coulombic interactions between ions give rise to the largely periodic behavior (alternating cation-anion structures) that is seen in ionic liquids. Hydrogen bonding is an important structure forming factor in many pure ionic liquids and the degree of the short-range cation-anion interactions is dependent upon which ions the ionic liquid is composed of. It has been demonstrated that ionic liquids can have dramatic effects upon the products and rates of chemical reactions. Industrial chemists have been exploring ionic liquids' potential commercial uses, particularly as process solvents.

Book chapter

Brandt-Talbot A, Murphy R, Leak D, Welton T, Hallett Jet al., 2014, Treatment, US2014073016 (A1)

The present invention relates to a method for treating a lignocellulose biomass in order to dissolve the lignin therein, while the cellulose does not dissolve. The cellulose pulp obtained can be used to produce glucose. In addition the lignin can be isolated for subsequent use in the renewable chemical industry as a source for aromatic platform chemicals.

Patent

Matthews RP, Welton T, Hunt PA, 2014, Competitive pi interactions and hydrogen bonding within imidazolium ionic liquids, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 16, Pages: 3238-3253, ISSN: 1463-9076

Journal article

Claudio AFM, Swift L, Hallett JP, Welton T, Coutinho JAP, Freire MGet al., 2014, Extended scale for the hydrogen-bond basicity of ionic liquids, Physical Chemistry Chemical Physics, Vol: 16, Pages: 6593-6601, ISSN: 1463-9084

In the past decade, ionic liquids (ILs) have been the focus of intensive research regarding their use as potential and alternative solvents in many chemical applications. Targeting their effectiveness, recent investigations have attempted to establish polarity scales capable of ranking ILs according to their chemical behaviours. However, some major drawbacks have been found since polarity scales only report relative ranks because they depend on the set of probe dyes used, and they are sensitive to measurement conditions, such as purity levels of the ILs and procedures employed. Due to all these difficulties it is of crucial importance to find alternative and/or predictive methods and to evaluate them as a priori approaches capable of providing the chemical properties of ILs. Furthermore, the large number of ILs available makes their experimental characterization, usually achieved by a trial and error methodology, burdensome. In this context, we firstly evaluated COSMO-RS, COnductor-like Screening MOdel for Real Solvents, as an alternative tool to estimate the hydrogen-bond basicity of ILs. After demonstrating a straight-line correlation between the experimental hydrogen-bond basicity values and the COSMO-RS hydrogen-bonding energies in equimolar cation–anion pairs, an extended scale for the hydrogen-bond accepting ability of IL anions is proposed here. This new ranking of the ILs' chemical properties opens the possibility to pre-screen appropriate ILs (even those not yet synthesized) for a given task or application.

Journal article

Verdia P, Brandt A, Hallett JP, Ray MJ, Welton Tet al., 2014, Fractionation of lignocellulosic biomass with the ionic liquid 1-butylimidazolium hydrogen sulfate, Green Chemistry, Vol: 16, Pages: 1617-1627, ISSN: 1744-1560

The application of the protic ionic liquid 1-butylimidazolium hydrogen sulfate in the deconstruction (aka pretreatment) and fractionation of lignocellulosic biomass has been investigated. A cellulose rich pulp and a lignin fraction were produced. The pulp was subjected to enzymatic saccharification which allowed recovery of up to 90% of the glucan as fermentable glucose. The influence of the solution acidity on the deconstruction of Miscanthus giganteus was examined by varying the 1-butylimidazole to sulfuric acid ratio. Increased acidity led to shorter pretreatment times and resulted in reduced hemicellulose content in the pulp. Addition of water to the ionic liquid resulted in enhanced saccharification yields. The ability to tune acidity through the use of protic ionic liquids offers a significant advantage in flexibility over dialkylimidazolium analogues.

Journal article

Skarmoutsos I, Welton T, Hunt PA, 2014, The importance of timescale for hydrogen bonding in imidazolium chloride ionic liquids, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 16, Pages: 3675-3685, ISSN: 1463-9076

Journal article

Graesvik J, Hallett JP, Trang QT, Welton Tet al., 2014, A quick, simple, robust method to measure the acidity of ionic liquids, CHEMICAL COMMUNICATIONS, Vol: 50, Pages: 7258-7261, ISSN: 1359-7345

Journal article

Ab Rani MA, Borduas N, Colquhoun V, Hanley R, Johnson H, Larger S, Lickiss PD, Llopis-Mestre V, Luu S, Mogstad M, Oczipka P, Sherwood JR, Welton T, Xing J-Yet al., 2013, The potential of methylsiloxanes as solvents for synthetic chemistry applications, Green Chemistry, Vol: 16, Pages: 1282-1296, ISSN: 1744-1560

The potential use of volatile methylsiloxanes (VMSs) as solvents for chemicals synthesis has been explored. Assessment of the environmental impact of these VMS solvents is made and found to be significantly lower than those of the non-polar organic solvents that they have the potential to replace. The polarities of the VMSs, as expressed by empirical polarity measurements, and miscibilities with other liquids are found to be similar to those of alkane solvents. Finally, some uses of VMSs as solvents for both organic and inorganic transformations are described. The VMSs provide environmentally more sustainable (greener) alternatives to the nonpolar solvents that they have the potential to replace.

Journal article

Deyko A, Cremer T, Rietzler F, Perkin S, Crowhurst L, Welton T, Steinrueck H-P, Maier Fet al., 2013, Interfacial Behavior of Thin Ionic Liquid Films on Mica, JOURNAL OF PHYSICAL CHEMISTRY C, Vol: 117, Pages: 5101-5111, ISSN: 1932-7447

Journal article

Smith AM, Lovelock KRJ, Gosvami NN, Licence P, Dolan A, Welton T, Perkin Set al., 2013, Monolayer to Bilayer Structural Transition in Confined Pyrrolidinium-Based Ionic Liquids, JOURNAL OF PHYSICAL CHEMISTRY LETTERS, Vol: 4, Pages: 378-382, ISSN: 1948-7185

Journal article

Smith AM, Lovelock KRJ, Gosvami NN, Welton T, Perkin Set al., 2013, Quantized friction across ionic liquid thin films, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 15, Pages: 15317-15320, ISSN: 1463-9076

Journal article

Niedermeyer H, Ashworth C, Brandt A, Welton T, Hunt PAet al., 2013, A step towards the a priori design of ionic liquids, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 15, Pages: 11566-11578, ISSN: 1463-9076

Journal article

Clough MT, Geyer K, Hunt PA, Mertes J, Welton Tet al., 2013, Thermal decomposition of carboxylate ionic liquids: trends and mechanisms, PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 15, Pages: 20480-20495, ISSN: 1463-9076

Journal article

Brandt A, Grasvik J, Hallett JP, Welton Tet al., 2013, Deconstruction of lignocellulosic biomass with ionic liquids, Green Chem., Vol: 15, Pages: 550-583-550-583

This paper reviews the application of ionic liquids to the deconstruction and fractionation of lignocellulosic biomass, in a process step that is commonly called pretreatment. It is divided into four parts: the first gives background information on lignocellulosic biomass and ionic liquids; the second focuses on the solubility of lignocellulosic biomass (and the individual biopolymers within it) in ionic liquids; the third emphasises the deconstruction effects brought about by the use of ionic liquids as a solvent; the fourth part deals with practical considerations regarding the design of ionic liquid based deconstruction processes.

Journal article

Welton T, Westcott S, 2012, A finite resource: Helium, Manufacturing Chemist, Vol: 83, ISSN: 0262-4230

Journal article

Baez JC, Baratin A, Freidel L, Wise DKet al., 2012, Introduction, Publisher: AMER MATHEMATICAL SOC

Book

Bulut S, Ab Rani MA, Welton T, Lickiss PD, Krossing Iet al., 2012, Preparation of [Al(hfip)4]--Based Ionic Liquids with Siloxane-Functionalized Cations and Their Physical Properties in Comparison with Their [Tf2N]- Analogues, CHEMPHYSCHEM, Vol: 13, Pages: 1802-1805, ISSN: 1439-4235

Journal article

Brandt A, Erickson JK, Hallett JP, Murphy RJ, Potthast A, Ray MJ, Rosenau T, Schrems M, Welton Tet al., 2012, Soaking of pine wood chips with ionic liquids for reduced energy input during grinding, Green Chemistry, Vol: 14, Pages: 1079-1085, ISSN: 1463-9262

Ionic liquids are of great interest as potential solvents/catalysts for the production of fuels and chemicals from lignocellulosic biomass. Attention has focused particularly on the pretreatment of lignocellulose to make the cellulose more accessible to enzymatic hydrolysis. Any biomass processing requires a reduction in the size of the harvested biomass by chipping and/or grinding to make it more amenable to chemical and biological treatments. This paper demonstrates that significant energy savings can be achieved in the grinding of pine wood chips when the ionic liquid is added before the grinding operation. We show that this is due to the lubricating properties of the ionic liquids and not to physico-chemical modifications of the biomass. A brief impregnation of the chipped biomass results in higher savings than a longer treatment.

Journal article

Niedermeyer H, Hallett JP, Villar-Garcia IJ, Hunt PA, Welton Tet al., 2012, Mixtures of ionic liquids, CHEMICAL SOCIETY REVIEWS, Vol: 41, Pages: 7780-7802, ISSN: 0306-0012

Journal article

Skarmoutsos I, Dellis D, Matthews RP, Welton T, Hunt PAet al., 2012, Hydrogen Bonding in 1-Butyl- and 1-Ethyl-3-methylimidazolium Chloride Ionic Liquids, The Journal of Physical Chemistry B, Vol: 116, Pages: 4921-4933-4921-4933

Journal article

Ab Rani MA, Brandt A, Crowhurst L, Dolan A, Hassan NH, Hallett JP, Hunt PA, Lui M, Niedermeyer H, Perez-Arlandis JM, Schrems M, To TQ, Welton T, Wilding Ret al., 2011, Erratum: Understanding the polarity of ionic liquids (Physical Chemistry Chemical Physics (2011) DOI: 10.1039/c1cp21262a), Physical Chemistry Chemical Physics, Vol: 13, ISSN: 1463-9076

Journal article

Hallett JP, Welton T, 2011, Room-Temperature Ionic Liquids: Solvents for Synthesis and Catalysis. 2, CHEMICAL REVIEWS, Vol: 111, Pages: 3508-3576, ISSN: 0009-2665

Journal article

Ab Rani MA, Brandt A, Crowhurst L, Dolan A, Hassan NH, Hallett JP, Hunt PA, Lui M, Niedermeyer H, Perez-Arlandis JM, Schrems M, To TQ, Welton T, Wilding Ret al., 2011, Understanding the polarity of ionic liquids (vol 13, pg 16831, 2011), PHYSICAL CHEMISTRY CHEMICAL PHYSICS, Vol: 13, Pages: 21653-21653, ISSN: 1463-9076

Journal article

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