br Limitations of the study
Limitations of the study
Possible conflicts of interest Dr. Fayemiwo or SAF has received full financial support from Europe Gilead Sciences Ltd. for his M.Sc. degree programme in Medical Mycology and has been paid for talks on behalf of AstraZeneca and GSK. Caroline Moore or CBM has received a travel grant from Astellas, been paid for talks on behalf of Pfizer and has received grant support from Pfizer. Philip Foden or PF doesn\'t have anything to declare. Dr. Denning or DWD holds Founder shares in F2G Ltd. a University of Manchester spin-out antifungal discovery company, in Novocyt which markets the Myconostica real-time molecular assays and has current grant support from the National Institute of Allergy and Infectious Diseases, National Institute of Health Research, NorthWest Lung Centre Charity, Medical Research Council, Global Action Fund for Fungal Infections and the Fungal Infection Trust. He acts or has recently acted as a consultant to T2 Biosystems, GSK, Sigma Tau, Oxon Epidemiology, Basilea, Pulmatrix and Pulmicort. In the last 3years, he has been paid for talks on behalf of Astellas, Dynamiker, Gilead, Merck and Pfizer. He is also a member of the Infectious Disease Society of America Aspergillosis Guidelines and European Society for Clinical Microbiology and Infectious Diseases Aspergillosis Guidelines groups. Malcolm Richardson or MDR acts a consultant for Gilead Science Europe, Astellas, MSD, Pfizer and Basilea. He is a member of the European Society for Clinical Microbiology and Infectious Diseases Aspergillosis Guidelines writing groups.
Acknowledgement We would like to acknowledge Europe Gilead Sciences Ltd. for providing support for the University of Manchester Masters Medical Mycology degree programme. We appreciate the support of Dr. Riina Rautemaa-Richardson, Dr. Lilyann Novak-Frazer, Mr. Rikesh Masania and Mrs. Julie Morris (medical statistician).
Introduction Gas hydrates are crystalline solid compounds in which gas molecules (called guest molecules) are surrounded by water molecules, forming a regular cavity crystalline structure. Gas molecules with a desirable shape and size such as methane, ethane, propane, carbon dioxide and etc. can be placed in the solid crystalline as guest molecules [1,2]. Gas hydrates have been studied in the literature due to either their industrial applications (in the gas separation, natural gas storage and transportation, etc.) or their industrial problem in blockage of natural gas transportation pipelines [3,4]. In the field of gas pipelines blockages, some chemicals called thermodynamic hydrate inhibitors have been introduced to prevent or delay the natural gas hydrate formation. Traditionally, particular types of these materials have been used as industrial inhibitors such as methanol, glycerol, 67 8 glycol, and triethylene glycol. However, new gas hydrate inhibitors such as ionic liquids have been recommended in the recent years [2,5]. Ionic liquids, known as salts with a melting point below the boiling point of water, though these materials are usually in the liquid phase at the room temperature . Along with experimental studies performed to identify the promising candidates of hydrate inhibitors, the thermodynamic modeling should also be conducted. There are two main approaches for thermodynamic modeling of gas hydrate formation and dissociation; 1) van der Waals-Platteeuw, 2) two-step hydrate formation theory of Chen and Guo [7,8]. Most of the research works in the field of thermodynamic modeling of gas hydrate phase equilibria have been performed through van der Waals-Platteeuw modeling approach since 1954 [, , , , ]. Chen and Guo [8,14], proposed an alternate statistical mechanics based hydrate model by presenting a two-step hydrate formation theory, where this new model was somewhat different from Van der Waals-Platteeuw model. At the first step, a quasi-chemical reaction is carried out to form a stoichiometric basic hydrate which contains basic and linked cavities. The second step involves the adsorption of gas molecules into the empty linked cavities. A new approach for thermodynamic modeling of gas hydrate formation was introduced by these concepts. After the presentation of this model by Chen and Guo, some researchers tried to predict the equilibrium temperatures and pressures of gas hydrate formation and dissociation using this theory coupled with various equation of states and/or equations of activity coefficients such as Patel–Teja, SAFT, PSRK, HKM, NRTL, UNIQUAC for fugacity calculation in the liquid and gas phase [, , , ]. In the case of gas hydrate formation in the presence of ionic liquids (especially imidazolium based), finding a proper equation of state for calculating the fugacity of these material would be important. Various models have been developed to model the phase behavior of ionic liquids. Kato et al. (2005) modeled the VLE behavior of various solutes (alkanes, alkenes, cycloalkanes, cycloalkenes, aromatics, alcohols, ketones, esters, ethers, and water) in ionic liquids such as 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [EMIM][BTI], 1-hexyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide [HMIM][BTI], 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide [BMPYR][BTI], using UNIFAC to calculate their activity coefficients . Alvaraz et al. (2008) modeled the phase behavior of ionic liquid-supercritical gas mixture (CO2 or CHF3) and ionic liquid-hydrocarbons systems using Peng-Robinson EoS coupled with the van der Waals and Wong–Sandler mixing rules. Their results indicated better representation of the experimental data using Wong-Sandler mixing rules, as expected . Karakatsani et al. (2007) modeled the solubility of carbon monoxide, oxygen and Trifluoromethane in [BMIM][PF6] with tPC-PSAFT, and showed that across all cases, the agreement between the model and experimental data for mixture was very good . H. Soltani Panah. (2017) used the Cubic Plus Association Equation of State (CPA EoS) to model the H2S and CO2 solubility in ionic liquids such as ([EMIM][eFAP], [EMIM][EtSO4], [EMIM][OTf], [EMIM][Tf2N], [BMIM][BF4], [BMIM][PF6], [HMIM][PF6], [HMIM][Tf2N], [OMIM][PF6], [OMIM][Tf2N], [OH-EMIM][BF4], [OH-EMIM][OTf], [OH-EMIM][PF6] and [HO-EMIM][Tf2N]) and compared the results with the SRK EOS. The results indicated that the percentage of average absolute deviation (ADD%) was lower than 10. He proposed 2B association scheme for all ionic liquids in the calculations and proved that the CPA EoS was a good candidate for thermodynamic modeling of ionic liquids .