Tetrabutylammonium chloride

The MOSC, designated as 1-Co, was synthesized following a published procedure30 (link). All purchased chemicals were of analytical or Sigma-Aldrich Selectophore^™ grade and used as-is, without any further purification. Bis(2-ethylhexyl)sebacate (DOS), high molecular weight poly(vinylchloride) (PVC), potassium tetrakis(4-chlorophenyl) borate (KTpClPB), AgNO₃, KCl, NH₄Cl, tetrabutylammonium chloride (TBAC), and ≥99.9% tetrahydrofuran (THF) were purchased from Sigma-Aldrich. Methylene blue was purchased from Merck Millipore. Ag/AgCl pellet (2 mm) was purchased from Warner Instruments. SU8 was purchased from Microchem. Concentration series were prepared using deionized (DI) water (18.2 MΩ·cm) and Fyris River water.

The following chemical compounds were used for DES preparation. As HBA, cholinium chloride ([Chol]Cl − 98% of purity) was purchased from Acros Organic^®; tetramethylammonium chloride ([N₁₁₁₁]Cl − 97% of purity) and tetrabutylammonium chloride [N₄₄₄₄]Cl − 97% of purity) were purchased from Sigma-Aldrich. As HBD, ethylene glycol (99.5% of purity) was purchased from Sigma-Aldrich; 1-propanol (99.5% of purity) was purchased from Merck; butanoic acid (99% of purity) was purchased from Riedel de Haën; hexanoic acid (98% of purity) was purchased from SAFC; and urea (99% of purity) from Panreac. All DES were prepared at a molar ratio of 1:1, HBA:HBD. Briefly, HBDs and HBAs were added gravimetrically to closed vials and heated in a heat block with constant agitation. After the formation of a transparent liquid, the mixture was cooled down to room temperature. For some of these eutectic mixtures a known volume of water was added. The water content of both starting materials and DES was determined by Karl Fischer titration as detailed elsewhere^{42 (link)} and considered in calculations regarding cytotoxicity benchmarks.

The chemicals used in this study—3-amino-1-propanol (AP), 2-(methylamino)ethanol (MAE), 2-(butylamino)ethanol (BEA), tetrabutylammonium bromide (TBAB), and tetrabutylammonium chloride (TBAC)—were purchased from Sigma-Aldrich. TBAC was purified by double crystallization from acetone by adding diethyl ether. All salts were dried under reduced pressure before use, TBAB at 323 K for 48 h while TBAC at 298.15 K for several days. The corresponding information and the chemical structures of the DESs components are presented in Table 1.

The chemicals used in this study, tetrabutylammonium chloride, tetrabutylammonium bromide, tetraethylammonium chloride and 3-amino-1-propanol were purchased from Sigma-Aldrich (Saint Louis, MO, USA) and were used as received, only TBAC was purified by double crystallization from acetone by adding diethyl ether. Prior to synthesis the salts were dried in a vacuum oven (Thermo Scientific, Waltham, MA, USA), at 323 K for 48 h and 298.15 K for 3 days, respectively for TBAB and both TBAC and TEAC. Corresponding data are presented in Table 1. Figure 1 shows the structures of compounds used for DES preparation. Carbon dioxide was supplied by Oxygen S.C. Gdansk (Gdansk, Poland) with purity grade 5.0.

Castor oil, 3-hexahydro-4-methylphtalic anhydride (MHHPA), trimethylolpropane triglycidyl ether (TMP), aqueous hydrogen peroxide (30 wt.%), glacial acetic acid (99.7 wt.%), tetrabutylammonium chloride (TBAC), and sulfuric acid (96 wt.%) were purchased from Sigma Aldrich (Sigma-Aldrich, Darmstadt, Germany).