N López-Salas

J M Vicent-Luna

E Posada

S Imberti

R Madero-Castro

S Calero

Maria Conchi

Ovin Concepcion

R Ania

M Jiménez-Riobóo

M C Gutiérrez

Ferrer

R M Madero Castro

C O Ania

R J Jiménez-Riobóo

M L Ferrer

F Del Monte
email: delmonte@icmm.csic.es

Further Extending the Dilution Range of the "Solvent-in-DES" Regime upon the Replacement of Water by an Organic Solvent with Hydrogen Bond Capabilities

Keywords: deep eutectic solvents, DESs dilutions, binary liquid mixtures, H-bond complexes, neutron scattering, 1 H NMR spectroscopy, Brillouin spectroscopy, local structure rearrangements

published or not. The documents may come

Introduction

With increasing pressure to improve the eco-friendly features of many chemical processes, the design (and use) of more sustainable solvents is by no means trivial. Within this context, deep eutectic solvents (DESs) [START_REF] Abbott | Novel solvent properties of choline chloride/urea mixtures[END_REF] gained particular relevance as they share some interesting properties with ionic liquids (ILs) [START_REF] Welton | Room-Temperature Ionic Liquids. Solvents for Synthesis and Catalysis[END_REF] -e.g., low flammability, stability against air and moisture, excellent solvation potential, chemical and thermal stability, high heat capacity, density and conductivity, and low vapour pressure -whose negative environmental impact has been lately a matter of concern.

DESs are obtained by combination between a hydrogen-bond donor (HBD) and a hydrogen-bond acceptor (HBA) in a proper molar ratio. 3,4,5 With the aim of obtaining even less-toxic and more biodegradable DESs, König's and Kroon's groups promoted the design of eutectic mixtures using either sugars 6,7 or natural organic acids, 8,9 whereas Choi et al. described the so-called NADESs (natural DESs) 10 containing sugars, natural organic acids and/or amino acids as HBDs and ChCl (an essential nutrient extracted from biomass and often regarded as a part of the B-complex vitamins 11 ) as the HBA. NADESs further improved the environmental sustainability of regular DESs, opening the path to their use in the field of green chemistry and sustainable processes. 12 It is worth noting that H-bonds governing components interactions in most of these eutectic mixtures make them quite compatible with water. Thus, further improvement of the greenness aspects of DESs and NADESs has been achieved by dilution with water. In this regard, water addition allows decreasing the typically high viscosity of DESs/NADESs. 13,14,15,16 It is worth noting that high viscosities are a serious drawback that, in many cases, has limited the ultimate performance of DESs/NADESs. 17,18 Nonetheless, attention to the dilution range has to be paid so that H-bond complexes between DES/NADES components are yet preserved, this is, within the "water-in-DES" regime. Otherwise, at pseudo-high dilutions in the so-called DES-inwater regime, a simple dilution of the individual DES/NADES components would be obtained. 19,20,21,22,23 While mixing water in controlled amounts -e.g., within the so-called water-in-DES regime 24 -has been widely accepted as a simple and practical way of altering DES chemical and thermodynamic properties (with viscosity and conductivity exhibiting an exponential evolution along with water content), 14,19,25,26,27,28,29,30,31 the study of DES dilutions with non-aqueous H-bond-forming solvents remains basically unexplored. It is worth noting the obvious interest of using organic solvents in those cases where any reagent or by-product is non-soluble, non-miscible or unstable in water, 32,33,34,35,36 the presence of water might alter the reaction kinetics (for instance, when water is a by-product), 37,38,39,40,41,42 or a co-solvent with low vapour pressure allows exploring reaction processes (high temperatures or solvothermal conditions, among others) not suitable for water. 43,44,45 Herein, we investigated the dilution with benzyl alcohol (BA) of a ternary DESs composed of resorcinol and urea (R and U, respectively, as the HBDs) and choline chloride (ChCl, as the HBA) in a 3:2:1 molar ratio. DES dilutions with different BA contents were named as RUChClnBA, with n being moles of BA per mole of DES in the different samples. Brillouin and 1 H NMR spectroscopies, neutron scattering with isotopic substitution together with empirical potential structure refinement (NDIS-EPSR), and molecular dynamic (MD) simulations were used to study both the neat form of RUChCl and the different BA dilutions. RUChCl and aqueous dilutions thereof have been recently studied by similar means thus providing an interesting background for the discussion of the results obtained in this work. 46 In this case, BA was chosen because of its natural occurrence (produced naturally by many plants and commonly found in fruits and teas, as well as in a variety of essential oils) and low acute toxicity (the median lethal dose, LD 50 , is 1.2 g/kg in rats). Moreover, the aromatic nature, the polarity (the dipole moment is 1.67 D) and the low vapor pressure (0.18 kPa at 60 °C) of BA provide this solvent some capabilities not provided by water. 47,48 Finally, we explored the suitability of RUChClnBA to obtain polymeric resins by polycondensation of R with para-phthalaldehyde (pPA, benzene-1,4-dicarboxaldehyde) as an alternative to DES-assisted polycondensations carried out in aqueous dilutions. 49,50,51,52,53,54,55

Results and Discussion

We first studied RUChCl0BA, RUChCl5.4BA, RUChCl11BA and RUChCl22BA using NDIS-EPSR (see experimental part for details and Table S1). 56,57 Details of the different isotopic substituted samples measured using NDIS and the atom labels assigned to R, U, Ch, Cl and BA in the EPSR simulation of the diffraction data are provided in Tables S2 andS3, and Fig. 1, respectively. MD simulations were also performed with the aim of gaining further insights into the properties of these systems at a molecular level. Moreover, it is worth noting how the density of DES dilutions with different BA contents obtained by MD simulations correlated well with the experimentally data (Fig. S1).

The agreement between experimental total diffraction data and their corresponding EPSR fits (Fig. S2) revealed the goodness of this approach to investigate our samples (i.e., in all the simulations, R-factors were 0.001 after ca. 5000 iterations).

The evolution of the solvents structure was followed by representing the total diffraction patterns of the fully deuterated samples (Fig. S3). As in previous results found in aqueous dilutions of DESs (both this one and others), 22,23,46,58 the absence of small-angle scattering features (i.e., in the range of Q=0.01-0.5 Å -1 , d=1.2-60 nm) demonstrated that RUChClnBA mixtures were not classically phase-separated. 22,23 It is worth noting some minor divergences in the region Q ≤ 2 Å -1 coming from the typical inelastic scattering corrections for 1 H nuclei in non-fully deuterated compounds (Fig. 1). Fig. S3 also revealed a nanostructure transition on the intermolecular level from sample RUChCl0BA (i.e., with two primary scattering features at Q = 1.39 and 2 Å -1 , the former greater than the latter) to RUChCl22BA (i.e., with just one primary scattering features at Q = 2 Å -1 typical of BA can we say this??). S4, Fig. S14-S17). Interestingly, the evolution of N coord along with BA dilution was similar to that happening along with aqueous dilution, 46 although not exactly the same. As for aqueous dilution, pRDFs obtained from both NDIS-EPSR and MD simulations corroborated the capital role played by the chloride anion (Cl) in the HB interactions of the neat DES (e.g., RUChCl0BA) was preserved upon the addition of BA in certain contents (e.g., RUChCl5.4BA and RUChCl11BA) (Fig. 3a). Actually, the N coord values found for HB interactions established by Cl with R, U and Ch in RUChCl5.4BA and RUChCl11BA just experienced a slight decrease as compared to those in the accommodation of the latter into the HB complex structure. It was only for high BA contents (e.g., RUChCl22BA) that the HB interaction between Cl and Ch became quite weak (e.g., N coord of Cl-Hco was only 0.12 in RUChCl22BA) (Fig. 3a). This low value of N coord was indicative of the rupture of the HB complexes characteristic of DESs. For instance, in our previous work dealing with aqueous dilutions of the same DES, N coord of Cl-Hco was even a bit higher (e.g., 0.19) in RUChCl32W, a dilution range where the system was defined as a simple aqueous solution of the individual components R, U and ChCl. 46 Moreover, BA was capable to self-correlate into the HB complex structure of RUChCl5.4BA and RUChCl11BA as water did in RUChCl11W (see Os-Hs in Fig. 3b, with "s" being either W or BA). Nonetheless, it is worth noting that self-correlation in RUChCl5.4BA and RUChCl11BA experienced a dramatic decrease as compared to neat BA or even to RUChCl22BA, as revealed by the plot of cluster probability versus cluster size as well as the MD simulation snapshots depicted in Fig. S18.

A closer analysis of the evolution of N coord along with BA dilution allowed distinguishing significant differences with aqueous dilutions. Thus, the N coord values between BA and DES components other than Cl (e.g., R, U and Ch) in RUChCl5.4BA and RUChCl11BA were well below those found in RUChCl11W (see Ou-Hs, Oc-Hs, Or-Hs, Os-Hco and Os-Hrp in Fig. 3b). Actually, the N coord values found for Oc-Hb, Or-Hb, Ob-Hco and Ob-Hrp were too low to consider the occurrence of effective HB interactions between BA and both R and Ch. It is worth noting that neither the size nor the aromatic nature of BA favoured strong HB interactions with all DES components as it happened with water. Moreover, the number of HBs capable to be formed by water and BA (e.g., 4 and 2, respectively) was also a limiting factor for BA (Fig. 4a,left). This is reflected in the linear fashion in which HB networks are formed in BA (Fig. 4b).

Actually, despite the average number of HB per water molecule (n HB ) decreased along with dilution for both water and BA (Fig. 4c), the plot of the percentage of solvent molecules that engage in n HBs (f i ) was just 1 in the "BA-in-DES" regime (for RUChCl5.4BA and RUChCl11BA) (Fig. 4d) whereas it was 3 in the "water-in-DES" regime (for RUChCl11W). 46 Interestingly, the molar ratio of solvent to DES in the "solvent-in-DES" regime was basically the same in aqueous and BA dilutions of RUChCl.

Nonetheless, it is worth noting that the water content in RUChCl11W was only 18-20 wt% whereas the BA content in RUChCl11BA was ca. 60-67 wt%. Moreover, this extended dilution range of the "BA-in-DES" regime where BA was yet successfully accommodated into the HB complex structure originally formed by R, U and ChCl was also reflected in the evolution of - interactions that are characteristic in neat BA (Fig. 4a, right). The tendency of - interactions changed for DES contents of ca. 35 wt%, when transitioning from the "DES-in-BA" regime into the "BA-in-DES" regime (Fig. 4c).

It seems that accommodation into the HB complex structure by HB interactions of BA with Cl and with U, as well as by self-correlation between BA molecules (Fig. S13) avoided the proper emplacement between BA molecules for - interactions .

The preservation of the "solvent-in-DES" regime even at extremely low DES contents was indeed an intriguing result that merits further investigation.

Unfortunately, DSC scans of BA dilutions of RUChCl displayed neither a melting point (T m ) nor a crystallization temperature (T c ) (Fig. S19). This behaviour is typical of noneasily crystallizable ILs and DESs 59 and limits the capability of DSC to study the formation of certain eutectic mixtures. As an alternative, we have been lately using Brillouin and 1 H NMR spectroscopy given their capability to study different co-solvents mixtures, 60,61,62,63,64 including DESs. 24,[27][28][29]65 Actually, Brillouin spectroscopy is a reliable technique to study non-ideal liquid binary mixtures. Brillouin scattering results from the inelastic interaction between light and thermal acoustic excitations in dielectric materials. Interestingly, the deviation from linearity experienced by these interactions at the eutectic composition of liquid binary mixtures where water is one of the main components allowed the certain assignment of the eutectic composition in different liquid binary mixtures 66, 67 including aqueous DES solutions. Actually, we have observed this deviation in the evolution along with the DES content of both the hypersonic velocity (v H ) and the opto-acoustic dispersion function (D 180 -function). 24, 27- 29, 65 In this work, we found that v H deviated from the linear pattern followed by the ultrasound velocity (v U , not accounting for acoustic dispersions) at a DES content of ca.

35 wt% (Fig. 5a).

We also studied by 1 H NMR the evolution of the chemical shifts of the different DES components along with the DES content (in wt%) (Fig. S20, Table S5). In particular, the protons at the aromatic ring of R experienced the most significant changes, with protons at 2-, 4-and 6-positions up-field shifting for DES contents of 40 wt% and above. It is well known that hydroxyl groups of R donate some of its electron density into the conjugated π system via resonance so the protons at 2-, 4-and 6-positions are upfield shifted, more so as the electron donating capability increases (Fig. 5b). This was actually our case with the hydroxyl group participating more and more actively in HB complexes as the DES content increases within the "BA-in-DES" regime.

Moreover, the self-diffusion coefficients of the different DES components (D R , D U and D Ch ) as well as of deuterated BA (D BA ) (Fig. S21, Table S6) followed the pattern observed for aqueous dilutions of RUChCl, this is, the self-diffusion coefficient of the solvent (either water or BA) is similar to those of all DES components at high DES contents and diverge at low DES contents, mainly from the DES content at which transition occurs from the "solvent-in-DES" regime to the "DES-in-solvent" one. 24,28,46 It is worth reminding the above-mentioned peculiarities of BA (molecular size and aromatic nature) to understand why the self-diffusion coefficient of water diverged further than that of BA in the "DES-in-solvent" regime. Interestingly, self-diffusion coefficients obtained from MD simulations agreed with those obtained experimentally (Fig. S21). Actually, previous works using MD simulations in heterogeneous liquid mixtures correlated changes in the slope of the diffusion-concentration plot to local structure rearrangements. 68 Finally, we also investigated the relaxation dynamics in BA dilutions of RUChCl by the determination of the spin-lattice relaxation time, T 1 . T 1 for R, U and ChCl were obtained as the averaged value from the different protons of the respective molecules (e.g., T 1_R , T 1_U , and T 1_ChCl ). The plots of 1/T 1_R , 1/T 1_U , and 1/T 1_ChCl versus DES content and versus viscosity exhibited a deviation at a DES content of ca. 35 wt% (Fig. 5c and5d). Interestingly, the similarities between both plots pointed to the intrinsic features of "BA-in-DES" and "DES-in-BA" regimes as the origin of the observed changes in T 1 . 24,69 As mentioned in the introduction, we aimed to promote the polycondensation of resorcinol in some of the above BA solutions of RUChCl to obtain resins, the carbonization of which is one of the most common synthetic processes used for preparation of porous carbon materials. 70,71,72 The polycondensation reaction is typically carried out in aqueous media, using formaldehyde as the cross-linker agent, and in the presence of either acid or basic catalysts as well as of soft or hard templates to finally obtain porous carbon materials. Introducing some textural properties in the resulting carbons is by no means trivial as it ultimately determines the field of application of these carbons -e.g., from water and air purification, adsorption, or catalysis, to electrodes and energy storage. 73,74 Unfortunately, the design of predictable process (not based on trial and error) is difficult when playing around with so many reagents (e.g., acids, bases, templates, and solvents). Minimizing the number of reagents would indeed help to rationalize the process. Previous DES-assisted polycondensations carried out using water as co-solvent have allowed to obtain carbon materials with co-continuous porous structures without the use of templates.

In order to avoid any eventual uncontrolled evaporation of water (that would make difficult to control the reaction kinetic, note water is a byproduct of the reaction), the temperature used at the initial stages of the polycondensation is typically around 60-70 C. This low temperature explains why renouncing to the use of catalysts in aqueous media is difficult.

RUChClnBA-assisted polycondensations opened interesting perspectives in this regard. As mentioned in the introduction, BA has some suitable solvent features (e.g., polarity and the low vapor pressure) to succeed as an alternative to water. Thus, polycondensation was carried out by addition of pPA to RUChCl3.6BA, RUChCl5.4BA, RUChCl8.2BA, RUChCl10BA, and RUChCl13BA with a fixed pPA to R molar ratio of 2 (Table S5) without the aid of any further catalyst and/or template. FTIR and solid-state 13 C CPMAS NMR spectroscopies revealed that the resulting resins (e.g., R RUChCl3.6BA , R RUChCl5.4BA , R RUChCl8.2BA , R RUChCl10BA , and R RUChCl13BA ) were obtained with conversions of ca. 60-70 %, this is, in range to those obtained in other DES-assisted polycondensations using water as the co-solvent (Fig. S22 and S23, Table S6). FTIR and solid-state 13 C CPMAS NMR spectroscopies also revealed the occurrence of certain U incorporation into the pPA-R network via condensation between pPA and U. 49 The formation of networks containing both R and U linked through pPA was also confirmed by chemical analyses. The nitrogen content in every sample was ca. 4.0-4.5 wt% (Table S6). R RUChCl3.6BA , R RUChCl5.4BA , R RUChCl8.2BA , R RUChCl10BA , and R RUChCl13BA exhibited different morphologies, from interconnected with either aggregate-of-particles or cocontinuous morphologies to open-cell pore morphologies. This sort of morphologies is typical of materials obtained via chemically induced phase separation (CIPS) 75,76 processes where the formation of a rich-polymer phase is accompanied by the segregation of the non-condensed matter (creating first a poor-polymer phase that, ultimately, becomes a depleted-polymer phase), the elimination of which (in our case, either before carbonization by washing or during carbonization by thermal decomposition) results in the formation of the above-mentioned porous structures. 77,78,79,80,81,82 CIPS processes can be illustrated on the phase diagram obtained by representing the reaction time versus composition with two unsymmetrical parabolic curves, an upper and a lower known respectively as the binodal and spinodal curves, meeting at the point of common curvature of both curves also known as the critical point (Fig. 6a). In particular, the spinodal curve demarcates the two-phase region into metastable and unstable regions, with the metastable region being defined between the binodal and spinodal curves, and the unstable region being defined below the spinodal curve. 78,83,84 The polymerization starts in the region defined above the binodal curve where the polymer solution exists as a stable single-phase system. When reaction proceeds, transitioning into either the metastable or unstable region occurs depending on the composition of the original solution. Entering into the metastable region provides for spheroidal domains through a nucleation and growth mechanism.

In these cases, polymers exhibit either an open-cell pore morphology 75,76 if the spherical domains correspond to the poor-polymer phase or an interconnected structure of aggregate-of-particles 85 if the spherical domains correspond to the richpolymer phase. Meanwhile, entering into the unstable region provides for cocontinuous domains through a spinodal decomposition mechanism. 78,86 For this purpose, anticipating the composition that allows entering into the unstable region (e.g., that of the critical point) is by no means trivial.

In our case, morphologies were open-cell like for R RUChCl3.6BA and R RUChCl5.4BA and aggregates-of-particles like for R RUChCl13BA and R RUChCl22BA , whereas co-continuous morphologies were found for R RUChCl8.2BA and R RUChCl10BA (Fig. 6b). The composition of the starting dilutions of these latter samples seem by and large simply to correspond those in which transition from the "solvent-in-DES" regime to the "DES-in-solvent" one occurs according to all the experimental techniques and MD simulations discussed above. Interestingly, the morphologies were preserved after carbonization so that, in the particular case of C RUChCl8.2BA and C RUChCl10BA , carbon materials with a co-continuous porous structure were obtained (Fig. 7). In any case, all carbons exhibited a bimodal porous structure with both macropores and micropores as revealed by Hg porosimetry and N 2 adsorption isotherms (Fig. S24 and S25, Table S7). The presence of micropores made these carbons suitable as CO 2 absorbents (Fig. S26, Table S8).

Conclusions

The N coord obtained for RUChClnBA by the combination of NDIS and EPSR revealed the existence of a "BA-in-DES" regime for a dilution range of up to RUChCl11BA (DES content, 33 wt%) where BA was successfully accommodated into the HB complex structure originally formed by R, U and ChCl. This DES content was within the 33-40-wt%-range where the "BA-in-DES" regime transitioned into the "DES-in-BA" one according to data coming from both Brillouin (v H ) and 1 H NMR (chemical shifts, self-diffusion coefficients and spin-lattice relaxation times) spectroscopies, as well as from MD simulations (self-diffusion coefficients). The presence of two well differentiated regimes -e.g., the "solvent-in-DES" and the "DES-in-solvent"depending on the DES content resembled the two well differentiated regimes observed in aqueous DES dilutions. However, it is worth noting that BA was capable to preserved the "solvent-in-DES" regime at much higher solvent contents than H 2 Oe.g., 60-67 versus 18-20 wt%, respectively. Interestingly, when these BA dilutions were used as the precursor for preparation of R-based resins via polycondensation, the composition capable to provide materials with co-continuous morphologies via an spinodal decomposition process was also that in which transition from the "solvent-in-DES" regime to the "DES-in-solvent" one occurs. These results revealed the capability of any of the above-mentioned techniques to anticipate the specific RUChClnBA dilution that allows entering into the unstable region (e.g., that of the critical point).

This issue is by no means trivial when one desires to control the morphology of the resulting materials.

Experimental Part

Materials: Resorcinol (R), urea (U), choline chloride (ChCl), benzyl alcohol (BA), and para-phthalaldehyde (pPA) were purchased from Sigma-Aldrich. Deuterated D7-benzyl alcohol (BA-d7 98%) and dimethylsulfoxide (DMSO-d6, 99,9%) were acquired from Tracer tecnologías analíticas. All the reagents were used as received but ChCl that was dried at 90 °C overnight prior to its use. After drying, the water content was negligible as determined by Karl Fisher titration using a Titrando 888. Water was distilled and deionized.

DES and DES dilutions preparation:

RUChCl DES was obtained by physical mixing of the individual components (R, U and ChCl in a 3:2:1 molar ratio) followed by a thermal treatment at 90 °C (see reference 37 in main text for further details). RUChClnBA dilutions (n = 1.4, 3.6, 4.5, 5.4, 7, 8, 10, 11, 13, 16, 22, and 49, for RUChCl contents of 80, 60, 55, 50, 45, 40, 35, 33, 30, 20, and 10 wt%, respectively, Table S1) were prepared by physical mixing of the DES and the corresponding BA amount at room temperature.

Carbons preparation:

Polycondensation was performed upon the addition of pPA to RUChCl3.6BA, RUChCl5.4BA, RUChCl8.2BA, RUChCl10BA, and RUChCl13BA with a fixed pPA to R molar ratio of 2. The mixture was homogenized by gently stirring and, then, thermally treated for 4 days at 90 °C to obtain R RUChCl3.6BA , R RUChCl5.4BA , R RUChCl8.2BA , R RUChCl10BA , and R RUChCl13BA . The resins were submitted to pyrolysis under a nitrogen atmosphere at 800 °C for 4 hours (the heating ramp was 1.0 °C/min) to obtain the respective carbons (C RUChCl3.6BA , C RUChCl5.4BA , C RUChCl8.2BA , C RUChCl10BA , and C RUChCl13BA ).

Samples characterization:

Densities, viscosities and ultrasonic velocities were measured in a DSA 5000M coupled with a LOVIS 2000 ME module from Anton Paar. Differential scanning calorimetry (DSC) analyses were performed in a TA Instruments Discovery system under a N 2 atmosphere. The samples were sealed in an aluminium pan and placed in the calorimeter furnace. For data acquisition, DESs were cooled from room temperature to -90 °C at a scan rate of 5 °C min -1 and kept at this temperature over 10 min before starting the heating/cooling cycles (two additional ones), which consisted of heating the sample to 60 °C (for all the dilutions) or 90 °C (for BA and RUChCl), and then cooling it again to -90 °C at the same scan rate. Resins were studied by Fourier transform infrared (FTIR) spectroscopy (using a FTIR spectrometer a NICOLET 20 SXC) and by solid-state 13 C-CPMAS-NMR spectroscopy (using a Bruker Model AV-400-WB spectrometer and applying a standard cross-polarization pulse sequence). The morphology of the different resins and carbons was studied by scanning electron microscopy (SEM), using a SEM Hitachi S-3000N system. Nitrogen Micromeritics system on samples thermally treated at 100 °C for 6 h prior to nitrogen gas adsorption. Brunauer-Emmett-Teller (BET) theory was used to calculate the specific surface areas (S BET ). Pore volumes were calculated using the 2D-NLDFT method (micropore and mesopore volume) and the Dubinin Radushkevich equation (micropore volume) applied to the N 2 adsorption data. CO 2 adsorption-desorption isotherms were performed at 0 and 25 °C in a Micromeritics Tristar 3020 instrument in the pressure range of 0.1-900 mbar. The narrow microporosity was further evaluated from the CO 2 adsorption isotherms using the Dubinin Radushkevich equation. Hg porosimetry was carried out using a Quantachrome Poremaster. Elemental analyses were carried out in a LECO CHNS-932 Analyser. The technique involved sample combustion at 1000 °C in an oxygen rich environment. The products of combustion (CO 2 , H 2 O and N 2 ) were carried through the system by He carrier gas. The combustion products were measured quantitatively by means of a non-dispersive IR absorption detection system, except for the N 2 that was determined via a thermal conductivity detector (TC).

Brillouin spectroscopy: Brillouin spectra were recorded using a Sandercock 3 + 3 Pass Tandem Fabry-Pérot interferometer as Brillouin spectrometer and the light source was a DPPS laser working at a wavelength (λ 0 ) of 532 nm. 87 In this case, the liquid samples were placed in optical cuvettes (Starna) with 1 mm in optical path length. Experiments were performed using backscattering and 90 A scattering geometry, simultaneously.

The simultaneous recording of both scattering geometries required of the use of a neutral filter for the Backscattering component and we also had to reduce the intensity of the central peak. The Brillouin peaks were fitted using a Lorentzian function with an adequate background function. The constraints associated with this experimental set-up made impossible the application of a typical damped harmonic oscillator model.

The 90A scattering geometry is independent of the refractive index (n) 2 and its acoustic wave vector is: 88 q 90A = [4πsin(π/4)] / λ 0 (1) The hypersonic sound propagation velocity (v H ) can be obtained from the relation between the Brillouin frequency shift (f 90A ) and q 90A , and expressed as

v H 90A = (2πf 90A ) / q 90A (2)
Meanwhile, the acoustic wave vector for Backscattering geometries is q 180 = [4πn] / λ 0 (3) and hence n-dependent. Thus, the hypersonic velocities for both geometries are:

v H 90A = f 90A λ 0 /√2 (4)
and v H 180 =f 180 λ 0 /2n (5)

1 H NMR analysis: Samples for 1 H NMR analyses were prepared by mixing RUChCl with the proper amount of BA-d7. [START_REF] Abbott | Novel solvent properties of choline chloride/urea mixtures[END_REF] H NMR spectra of RUChClnBA D were recorded using a Bruker Avance DRX500 spectrometer operating at 500 MHz with a 30° pulse, acquisition time of 3.1719 s, relaxation delay of 1 s and 16 scans. The samples were placed in capillary tubes whereas the DMSO-d6 used as the external reference was placed in 5 mm NMR glass tubes with a height of 8 inches. The peaks were identified and spectra were processed using the software MestReNova. 1 H NMR diffusion experiments were performed using a pulsed-field gradient stimulated spin-echo (PFG-STE NMR) technique by applying a LED-bipolar gradients pulse sequence from Bruker (in particular, ledbpgp2s pulse sequence). 89 The spectrometer was equipped with a broadband fluorine observe (BBFO) NMR probe capable of producing magnetic fields pulses in the z-direction. A Bruker Variable Temperature BVT 3000 was also used to set the temperature to 353 K for the measurements of samples.

The NMR signal attenuation (I/I 0 ) is described by the equation ( 6): 90

I = I 0 𝑒 -𝐷𝛾 2 𝑔 2 𝛿 2 (Δ-𝛿 3 ) (6)
Or in a simplified form (7):

I = I 0 𝑒 -𝐷𝑄 (7)
where, I is the observed intensity, I 0 is the intensity when the gradient strength is zero (reference intensity), D is de diffusion coefficient, 𝛾 is the gyromagnetic ratio of the observed nuclei, 𝑔 is the gradient strength, 𝛿 is the duration of the gradient and Δ is the diffusion time. The gyromagnetic ratio is different for every nucleus, being 4.3 kHz G -1 for 1 H. The duration of the gradient and the diffusion time differ among samples.

For the measurement of the spin-lattice relaxation time (T 1 ) the standard method of inversion recovery is applied. In this method, the following equation ( 8) is used: 91

I = I 0 [1 -2𝑒 ( -t T 1 ⁄ ) ] (8)
The software MestReNova was used for calculation of the diffusion coefficients and T 1 by the peak integration and fitting of the exponentially decaying data based on the area.

Neutron diffraction experiments: Hydrogenated resorcinol, urea, choline chloride and deuterated BA (97%-d7) were purchased from Tracer and used as received. d9-choline chloride ((CD 3 ) 3 N(CH 2 ) 2 OHCl, 98.8%-d9) was acquired from CIL laboratories. d4-urea (97.0%-d4) and d6-resorcinol (65.0%-d6) were prepared by ISIS Deuteration Facility.

Neutron diffraction experiments were carried out on RUChCl0BA, RUChCl5.4BA, RUChCl11BA, and RUChCl22BA (Table S1). Different isotopic substitution RUChCl samples were prepared by mixing the appropriate amount of the fully protonated and deuterated compounds and letting the mixture melt at 80 °C. The different isotopic contrasts are summarized in Table S2.

Neutron diffraction experiments were collected using the NIMROD diffractometer, Empirical potential structure refinement (EPSR) 92 and EPSRgui 93 were used to obtain computational models of the different systems. EPSR algorithm minimizes the system energy and, at the same time, builds an atomistic model that fits the collected data.

Previous to be used in EPSR algorithm, neutron scattering data were treated using GudrunN in order to correct them according to detectors efficiency, subtract environment background, multiple scattering, and hydrogen inelastic scattering. 94 Final datasets were then analyzed using EPSR that allowed to maximize the information obtained from them and allows comparing data with conventional simulations. The assigned bond lengths and atom types used to build the atomistic models are described in Table S3. Urea and choline chloride charges, masses and Lennard-Jones S4. The initial configurations were created by randomly placing the RUChCl constituents in an empty simulation box and refilled with BA molecules using the Packmol package, 102 thus obtaining a homogeneous distribution of the molecules. We started the equilibration of the system by performing an energy minimization simulation employing a steepest descent algorithm. 103 We continued with consecutive MD simulations in the NPT ensemble to relax the systems to their equilibrium density. This equilibrium is reached when the cell volume and the energy of the system fluctuate around an average value over time. Once the system was equilibrated we carried out MD simulations in the NVT ensemble to obtain the rest of the structural and dynamical properties of the RUChClnBA dilutions. The time step employed for the equilibration and production run simulations is 0.5 and 1 fs, respectively. The production runs consist in 50 million of MD steps giving rise to 50 ns of total simulation time. The pressure in the NPT simulations was set using the Martyna-Tuckerman-Tobias-Klein (MTTK) barostat, 104 and the temperature was controlled with the Nose-Hoover thermostat. 105,106 All simulations were performed using the GROMACS molecular simulation software. [107][108][109][110] Self-diffusion coefficients D MD were computed using Einstein's equation that relates D MD with the slope of the mean square displacement in the 10-40 ns time interval.

Additional details about the calculation of the transport properties of liquid systems can be found elsewhere (for further details see references 111,112 and also reference 45

in main text). The calculation of hydrogen bonds we performed using the geometric criterion described by Luzar and Chandler 113 over the trajectory recorded every 0.1 ns. S1b). Deviations occur within the range of 35-40 wt% in DES content. 9.2 2.0 2.0 7.5 16.3 6.0 2.9 3.0 1.65 1.95 2.77 4.43 5.12 5.71 5.73 5.88 6.17 9.7 2.1 2.0 7.0 13.7 6.0 2.9 3.0 1.66 1.97 2.78 4.48 5.25 5.71 5.73 5.89 6.17

Fig. 2 and

 2 Fig. 2 and Fig. S4-S13 display both centre-of-mass to centre-of-mass radial distribution functions (RDFs) as well as partial atom-to-atom radial distribution functions (pRDFs) obtained from EPSR. Coordination numbers (N coord ) and spatial density function (SDF) plots were also obtained by the combination of NDIS and EPSR (TableS4, Fig.S14-S17). Interestingly, the evolution of N coord along with BA dilution was

  located in Target Station 2 in the ISIS Neutron and Muon Facility, Rutherford Appleton Laboratories, Harwell Campus, UK. Neutron scattering data were recorded placing each freshly prepared solution into 1mm thickness flat TiZr alloy cans. Samples were kept at 353 K using a circulating heater to ensure the DES remained in liquid phase during the whole data collection time.

  parameters used were the same as in reference #46 and #58. Resorcinol Lennard-Jones parameters were adapted from Jorgensen95 and masses and charges extracted fromHussain et al. 96 and from reference #46. The simulation boxes contain 7000 molecules, at the density of 0.1 atoms/Å 3 .Molecular dynamics (MD) simulations:MD simulations were performed to study the structural and transport properties of the DES RUChCl in presence of water. The molecular models for the molecules of urea, choline, and chloride are taken fromPerkins et al. 97 In that work, the authors stated that the developed force field reproduces the physico-chemical properties of the urea/choline chloride DES, and in particular density, volume expansion coefficient, heat capacity and diffusion coefficients. We use OPLS-AA force field 8, 98 for resorcinol HBD, and SPC/E model for water.99 To calculate the cross Lennard-Jones potential parameters we use standard Lorentz-Berthelot combining rules. The Lennard-Jones cut-off radius is set to 12 Å and electrostatic interactions are computed using the Ewald summation technique.100, 101 We applied periodic boundary conditions in the three dimensions. Different concentrations covering the whole range from the pure solvent to the pure RUChCl with eleven intermediate weight percentages of RUChCl were studied. The components of the mixtures were initially placed in a cubic simulation box of approximately 40 Å. The number of ion pairs and organic compounds of each system, as well as the total number of atoms are shown in the Table

Figure 7 :Figure 6 :Figure 5 :

 765 Figure 7: SEM micrographs of CRUChCl3.6BA, CRUChCl5.4BA, CRUChCl8BA, CRUChCl10BA, CRUChCl13BA, and CRUChCl22BA.

Figure 4 :Figure 3 :Figure 2 :Figure 1 :

 4321 Figure 4: (a) MD simulation snapshot showing BA self-interactions, HB type between one BA molecule and two adjacent ones, and p-p between one BA molecule and one adjacent one. Carbon atoms in blue, hydrogen atoms in white and oxygen atoms in red. Distances used in MD simulations were xx for HB and yy for p-p. (b) MD simulation snapshot of the lineal HB network (in orange) formed in neat BA. Carbon atoms in blue and oxygen atoms in red. (c) Average number of HBs (red circles) and of p-p interactions (blue diamonds) per molecule of BA versus DES content (in wt %). (d) Probability of finding molecules of BA forming HBs in RUChCl0BA (red circles), RUChCl5.4BA (blue triangles), RUChCl11BA (green squares), and RUChCl21BA (purple diamonds), as obtained from MD simulation.

Figure S21 :

 S21 Figure S21: Plot of self-diffusion coefficients of R, U, Ch and BA versus DES content (in wt%), as obtained from NMR spectroscopy and from MD simulations at 353 K. Check data, correct x axis label "DES content (wt%)", anything else?

Figure S23 :Figure S24 :Figure S25 :

 S23S24S25 Figure S23: Solid-state 13 C CPMAS NMR spectra of RUChCl3.6BA (a), RUChCl5.4BA (b), RUChCl8BA (c), RUChCl10BA (d), RUChCl13BA (e), and RUChCl22BA (f).

Figure S26 :

 S26 Figure S26: CO2 adsorption isotherms obtained at 273 K (a) and at 298 K (b) for the different porous carbon materials prepared in this work.

Table S1 :

 S1 Components contents (as molar ratios and wt%) in the different samples. Samples studied by NDIS-EPSR are in red.

Table S2 :

 S2 Summary of the different isotopic substitution used in RUChCl22BA, RUChCl11BA and RUChCl5.4BA to carry out the neutron scattering experiments.

	DES content	BA content	R		U	ChCl	BA			Sample
		(wt%)		(wt%)	(mol)	(mol)	(mol)	(mol)
		100			0		3		2		1	0		RUChCl0BA
		80			20		3		2		1	1.4		RUChCl1.4BA
		60			40		3		2		1	3.6		RUChCl3.6BA
		55			45		3		2		1	4.5		RUChCl4.5BA
		50			50		3		2		1	5.4		RUChCl5.4BA
		45			55		3		2		1	6.7		RUChCl7BA
		40			60		3		2		1	8.2		RUChCl8BA
		35			65		3		2		1	10.1		RUChCl10BA
		33			67		3		2		1	11		RUChCl11BA
		30			70		3		2		1	12.7		RUChCl13BA
		25			75		3		2		1	16.3		RUChCl16A
		20			80		3		2		1	21.8		RUChCl22BA
		10			90		3		2		1	49.1		RUChCl49BA
			RUChCl22BA			RUChCl11BA				RUChCl5.4BA
	ID	R	Composition U C	BA	DSC Level	R	U	C BA	DSC Level	R	U	C BA	DSC Level
	11	D	D	D	D	20%a 21 D	D	D	D	OK	31 D	D	D	D	OK
	12	H	D	D	D	OK	22 H	D	D	D	OK	32 H	D	D	D	OK
	13	D	H	D	D	OK	23 D	H	D	D	OK	33 D	H	D	D	OK
	14	D	D	H	D	OK	24 D	D	H	D	OK	34 D	D	H	D	OK
	15	D	D	D	H	OK	25 D	D	D	H	OK	35 D	D	D	H	OK
	16	H	H	H	H	OK	26 H	H	H	H	OK	36 H	H	H	H	OK
	17 DH DH DH DH	OK	27 DH DH DH DH	OK	37 DH DH DH DH	OK
	18 DH D	D	D	OK	28 DH D	D	D	OK	38 DH D	D	D	OK
	19	D DH D	D	OK	29 D DH D	D	OK	39 D DH D	D	OK
	110 D	D DH	D	OK	210 D	D DH D	NM	310 D	D DH D	OK
	111 D	D	D	DH	OK	211 D	D	D DH	OK	311 D	D	D DH	OK
		* a: above, b: bellow, OK: Sample and Gudrun DSC levels coincides, NM: Not measured

Table S3 :

 S3 Lennard-Jones parameters, masses, and point charges used in the reference potential to simulate RUChCl DES components and BA. Atom types are depicted in Figure1of the manuscript.

	Figure S20: 1 H NMR spectra of RUChCl and BA dilutions thereof, with DES contents of (a) 100 wt%,
	(b) 80 wt%, (c) 60 wt%, (d) 50 wt%, (e) 40 wt%, (f) 35 wt%, (g) 30 wt%, (h) 25 wt%, (i) 20 wt%, and
	(j) 10 wt%.												Atom type ε (kJ/mol) σ (Å)				mass (amu)	q (e)
																	Cr5				0.293		3.550				12.011	0.098
	a																Cr4				0.293 b		3.550				12.011	-0.589
																	Hr5				0.126		2.420				2.000	0.133
																	Cr1				0.293		3.550				12.011	0.601
				Resorcinol				Hr4				0.126		2.420				2.000	0.198
																	Cr2				0.293		3.550				12.011	-0.585
																	Or					0.711		3.070				15.999	-0.622
	c															Hr2 Hrp				0.126 0.000 d		2.420 0.000				2.000 2.000	0.266 0.456
																	Cu					0.439		3.750				12.011	0.152
									Urea						Ou Nu					0.878 0.711		2.960 3.250				15.999 14.007	-0.390 -0.541
																	Hu					0.000		0.000				2.000	0.330
																	Nc					0.700		3.200				14.007	1.000
	e																Cc4				0.800 f		3.700				12.011	-0.120
																	Cc1				0.800		3.700				12.011	-0.180
																	Cc5				0.800		3.700				12.011	0.145
						Choline				Hc4				0.200		2.580				2.000	0.060
																Hc1				0.200		2.580				2.000	0.060
																	Oc					0.650		3.100				15.999	-0.683
	g			6.17	5.89	5.73	5.71	4.96	4.42			Hc5 2.76	1.95	1.65		0.200 h		2.580 6.18	5.89	5.73	5.71	2.000 4.36 4.63	2.75	0.060 1.63 1.94
																Hco				0.000		0.000				2.000	0.418
						Chloride				Cl					0.566		4.191				35.453	-1.000
																Cb1				0.28			3.50					12.01	-0.06
																Cb2				0.29			3.55					12.01	-0.12
					3.0	3.0	6.0	18.1	7.6			Cbm 2.0 2.0	9.2		0.28			3.50		3.1	3.0	6.1	12.01 8.1 24.9	2.0	0.15 9.1 2.1
	8.0	7.5	7.0	6.5		6.0		5.5	5.0	4.5	4.0	3.5	3.0	2.5	2.0	1.5	1.0		8.0	7.5	7.0	6.5		6.0	5.5	5.0	4.5	4.0	3.5	3.0	2.5	2.0	1.5	1.0
											δ (ppm)			Cb3				0.29			3.55					12.01 δ (ppm)	-0.12
	i			6.18	5.89	5.73	5.71		4.52	4.34			Hb2 2.74	1.94	1.63		0.13 j			2.42	6.19	5.89	5.74	5.72	2.00 3.96 4.23	3.02	2.73	0.12 1.62 1.94
							Benzyl alcohol				Hbm Ob			0.13 0.71			2.50 3.12					2.00 16.00	0.04 -0.68
																Cb4				0.29			3.55					12.01	-0.12
																Hb3				0.13			2.42					2.00	0.12
	8.0	7.5	7.0	6.5	6.0 3.2 3.1	5.5 6.2	5.0	4.5 35.6	4.0	3.5	3.0	Hb 2.5 2.0	2.0 2.0	1.5 9.1	1.0	0.00	8.0	7.5	0.00 6.5 7.0	6.0 3.1 2.9	5.5 5.8	5.0	2.00 4.0 4.5 55.2	3.5	3.0	2.5 2.0	1.5 0.52 2.0 9.2 2.0	1.0
											δ (ppm)			Hb4				0.13			2.42					2.00 δ (ppm)	0.12

Table S5 :

 S5 Chemical shifts obtained in the 1 H NMR spectra of RUChCl and BA dilutions thereof, with different DES contents.

															Chemical Shifts (ppm)
	DES content	2.91 Exchangeable protons 4.76 5.67 5.68 5.80 6.18 6.94		2.13	1.83	H	Resorcinol H		6.58 H at	6.17	5.83	5.70	4.67 Urea (NH2)2-5.68	2.85 -CH2-	1.74 Choline Chloride 2.05 -CH2-(CH3)3-
	(wt%)			from R, ChCl and BA*			at C5	at C2		C4 & C6	CO	HO	N +	N +
	100								6.94					6.18	5.80			5.68			4.76	2.91	2.13	1.83
						(6HR + 1HChCl)					(3H)	(3H)			(6H)			(8H)	(2H)	(2H)	(9H)
	80								6.58					6.17	5.83			5.70			4.67	2.85	2.05	1.74
				(6HR + 1HChCl + 1HBA)				(3H)	(3H)			(6H)			(7.9H)	(2H)	(2H)	(9H)
	60		7.0	3.1	3.1	6.3		8.0 6.02	2.0		2.0	9.2	6.17	5.85			7.9 5.70	3.1	3.1	6.4	7.9 4.58	2.0 2.81	2.1	9.5 2.00	1.70
	8.0	7.5	7.0	2.5 (6HR + 1HChCl + 3.4HBA) 3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 δ (ppm)	2.0	1.0 (3H) 1.5	(3H)	8.0	7.5	6.5 (6H) 7.0		6.0	4.5 δ (ppm) (7.,8H) 5.0 5.5	4.0	3.0 (2H) 3.5	2.5	1.5 (2H) 2.0	1.0	(9H)
	50							6.1-5.5					6.17	5.86			5.70			4.51	2.79	1.97	1.67
				6.17	6.02	5.85	5.71	5.69	4.58	2.81			2.00	1.70 (3H)	(3H)			(6H)		6.17	5.86	5.72	4.51 (8.5H) 5.70	2.79 (2H)	1.67 (2H) 1.98	(9H)
	40								5.25					6.17	5.89			5.73			4.48	2.78	1.97	1.66
				(6HR + 1HChCl + 6.7HBA)			(2.9H)	(2.7H)		(5.8H)		(6.7H)	(2H)	(2H)	(9H)
	35								6.49					6.17	5.88			5.72			4.43	2.76	1.96	1.65
				(6HR + 1HChCl + 9.3HBA)				(3H)	(3H)			(6H)			(7.6H)	(2H)	(2H)	(9H)
	30								6.31					6.17	5.89			5.72			4.42	2.77	1.96	1.65
	25			2.0 (6HR + 1HChCl + 11HBA) 7.8 6.2 3.2 10.0 3.2 4.63			2.0	9.2 (3H) 6.18	(3H) 5..89			(6H) 5.72			3.6	23.5	8.3 (7.6H) 4.36	2.0 (2H) 2.75	9.1 (2H) 2.0 1.94	(9H) 1.63
	8.0	7.5	7.0	3.0 (6HR + 1HChCl + 18HBA) 3.5 4.0 4.5 5.0 5.5 6.0 6.5 δ (ppm)	2.5		2.0	1.0 (3H) 1.5	(3H)			(6H)			(7.9H)	(2H)	(2H)	(9H)
	20								4.52					6.18	5.89			5.72			4.34	2.74	1.95	1.63
			(6HR + 1HChCl + 20.6HBA)			(3H)	(3H)			(6H)			(8H)	(2H)	(2H)	(9H)
	10								3.96					6.19	5.89			5.73			4.23	2.73	1.95	1.62
				(6HR + 1HChCl + 40HBA)				(3H)	(3H)			(6H)			(8H)	(2H)	(2H)	(9H)

Table S8 :

 S8 Summary of data obtained for CRUChClnBA samples from N2 adsorption/desorption isotherms at 77 K. Determined applying the BET equation to the N2 adsorption isotherms. b Determined at p/p ≈ 0.99. c Determined applying the 2D-NLDFT-HS method to the N2 adsorption data. d Determined applying the DR method to the N2 adsorption data.

	Sample	SBET (m²/g) a	Total Volume (cm³/g) b	Mesopore Volume (cm³/g) c	Micropore Volume (cm³/g) c	Micropore Volume (cm³/g) d
	CRUChCl3.6BA	48	0.03	--	--	--
	CRUChCl5.4BA	535	0.61	0.38	0.19	0.19
	CRUChCl8BA	414	0.40	0.22	0.15	0.16
	CRUChCl10BA	406	0.49	0.29	0.15	0.15
	CRUChCl13BA	357	0.30	0.17	0.13	0.13
	CRUChCl22BA	571	0.30	0.06	0.21	0.22

a

Table S9 :

 S9 Summary of data obtained for CRUChClnBA samples from CO2 adsorption/desorption isotherms at 273 K. Determined applying the DR method to the CO2 adsorption isotherms.

	Sample	SDR (m²/g) a	Smicro (m²/g) a	Wo (cm³/g) a	Eo (kJ/mol) a	L (nm) a
	CRUChCl3.6BA	583	886	0.26	30.1	0.58
	CRUChCl5.4BA	578	910	0.25	30.7	0.56
	CRUChCl8BA	603	933	0.26	30.5	0.57
	CRUChCl10BA	611	944	0.27	30.4	0.57
	CRUChCl13BA	533	836	0.23	30.7	0.56
	CRUChCl22BA	624	977	0.27	30.6	0.56
	a .

Acknowledgements

This work was supported by MINECO/FEDER (Project Numbers RTI2018-097728-B-I00 and RTI2018-096918-B-C41). C.O.A. and F.d.M. acknowledge CNRS and CSIC for PICS-07948 and PIC2017FR3, respectively. The Servicio Interdepartamental de Investigación (SIdI) of the Universidad Autónoma de Madrid is acknowledged for helpful assistance with NMR and DSC studies.

Supporting Information

The Supporting Information is available free of charge at https://pubs.acs.org/xxx Xxx (PDF).

Conflict of Interest

The authors declare no competing financial interest. * The different contrasts are labeled acording to RUChClnBA isotopes. Note that H stands for the fully protonated isotope of a given molecule, D for the deuterated one whereas M stands for a 50 wt% mixture of H and D compounds (e.g., DDDM stands for fully deuterated R, U and Ch mixed with a 50 wt% mixture of D/H isotopes of BA).

RUChCl0BA

RUChCl5.4BA

RUChCl11BA RUChCl22BA

Figure S3: Total diffraction shown as a function of Q of the different samples. U-R Or Hu 1.0 -2.5 0.29 ± 0.52 0.15 ± 0.38 0.10 ± 0.32 0.07 ± 0.27 Ch-R Or Hco 1.0 -2.5 0.03 ± 0.18 0.01 ± 0.12 0.02 ± 0.13 0.01 ± 0.10 BA-R Or Hb 1.0 -2.5 -0.12 ± 0.33 0.17 ± 0.38 0.22 ± 0.42

R-U

Ou Hrp 1.0 -2.9 0.61 ± 0.73 0.34 ± 0.55 0.27 ± 0.48 0.13 ± 0.33 U-U Ou Hu 1.0 -2.9 2.84 ± 1.21 2.34 ± 1.05 2.30 ± 1.03 2.21 ± 0.98 Ch-U Ou Hco 1.0 -2.9 0.09 ± 0.29 0.08 ± 0.27 0.05 ± 0.21 0.02 ± 0.15 BA-U Ou Hb 1.0 -2.9 -0.31 ± 0.51 0.50 ± 0.62 0.66 ± 0.66

R-Cl

Cl Hrp 1.3 -2.6 1.32 ± 0.88 0.93 ± 0.86 0.77 ± 0.79 0.44 ± 0.71

U-Cl

Cl Hu 1.3 -2.6 0.99 ± 1.00 0.60 ± 0.81 0.44 ± 0.70 0.28 ± 0.58 Ch-Cl Cl Hco 1.3 -2.6 0.32 ± 0.54 0.33 ± 0.51 0.25 ± 0.47 0.12 ± 0.32 BA-Cl Cl Hb 1.3 -2.6 -0.92 ± 0.85 1.32 ± 0.87 1.80 ± 0.96 R-Ch Oc Hrp 1.0 -2.5 0.24 ± 0.45 0.19 ± 0.40 0.09 ± 0.28 0.08 ± 0.28 U-Ch Oc Hu 1.0 -2.5 0.30 ± 0.50 0.16 ± 0.40 0.12 ± 0.33 0.07 ± 0.28 Ch-Ch Oc Hco 1.0 -2.5 0.54 ± 0.56 0.57 ± 0.53 0.52 ± 0.52 0.49 ± 0.50 BA-Ch Oc Hb 1.0 -2.5 -0.15 ± 0.37 0.26 ± 0.45 0.31 ± 0.46 R-BA Ob Hrp 1.0 -2.5 -0.21 ± 0.44 0.19 ± 0.43 0.17 ± 0.43 U-BA Ob Hu 1.0 -2.5 -0.21 ± 0.45 0.19 ± 0.45 0.17 ± 0.44 BA-BA Ob Hb 1.0 -2.5 -0.71 ± 0.62 0.79 ± 0.67 0.87 ± 0.71 Ch-BA Ob Hco 1.0 -2.5 -0.09 ± 0.32 0.10 ± 0.35 0.12 ± 0.39 R-U Nu Hrp 1.3 -4.