Strategy for Synthesizing Novel Acetamidines as CO₂-Triggered Switchable Surfactants via Acetimidates

Abstract

In this study, we developed a strategy for using the Scoggins procedure in the synthesis of acetamidines as novel CO₂-triggered switchable surfactants via acetimidates by effectively tuning the chemical equilibrium. The as-synthesized N’-alkyl-N,N-diethylacetamidines exhibit excellent CO₂/N₂ switchability and their bicarbonate salts have the ability to emulsify oil–water mixtures.

Keywords

CO₂ switchable surfactants / Acetimidate / Acetamidine / Consecutive reaction

References

[1] Behera MR, Varade SR, Ghosh P, et al. Foaming in micellar solutions: effects of surfactant, salt, and oil concentrations. Ind Eng Chem Res, 2014, 53(48): 18497-18507.

[2] Huang C, Karimi IA. Scheduling tanker-lightering operations in crude oil transportation. Ind Eng Chem Res, 2006, 45(24): 8063-8082.

[3] Sharma T, Iglauer S, Sangwai JS. Silica nanofluids in an oilfield polymer polyacrylamide: interfacial properties, wettability alteration and applications for chemical enhanced oil recovery. Ind Eng Chem Res, 2016, 55(48): 12387-12397.

[4] Ren G, Wang L, Chen Q, et al. PH switchable emulsions based on dynamic covalent surfactants. Langmuir, 2017, 33(12): 3040-3046.

[5] Feng A, Peng L, Liu B, et al. Electrochemical redox switchable dispersion of single-walled carbon nanotubes in water. ACS Appl Mater Interfaces, 2016, 8(17): 11024-11030.

[6] Melle S, Lask M, Fuller GG. Pickering emulsions with controllable stability. Langmuir, 2005, 21(6): 2158-2162.

[7] Li L, Rosenthal M, Zhang H, et al. Light-switchable vesicles from liquid-crystalline homopolymer-surfactant complexes. Angew Chem Int Ed, 2012, 51(46): 11616-11619.

[8] Jessop PG, Mercer SM, Heldebrant DJ. CO₂-triggered switchable solvents, surfactants, and other materials. Energy Environ Sci, 2012, 5(6): 7240-7253.

[9] Jessop PG, Heldebrant DJ, Li X, et al. Green chemistry: reversible nonpolar-to-polar solvent. Nature, 2005, 436(7054): 1102

[10] Samorì C, Cespi D, Blair P, et al. Application of switchable hydrophilicity solvents for recycling multilayer packaging materials. Green Chem, 2017, 19(7): 1714-1720.

[11] Jiang J, Zhu Y, Cui Z, et al. Switchable pickering emulsions stabilized by silica nanoparticles hydrophobized in situ with a switchable surfactant. Angew Chem Int Ed Engl, 2013, 52(47): 12373-12376.

[12] Jiang J, Ma Y, Cui Z, et al. Pickering emulsions responsive to CO₂/N₂ and light dual stimuli at ambient temperature. Langmuir, 2016, 32(34): 8668-8675.

[13] Darabi A, Jessop PG, Cunningham MF. CO₂-responsive polymeric materials: synthesis, self-assembly, and functional applications. Chem Soc Rev, 2016, 45(15): 4391-4436.

[14] Su X, Jessop PG, Cunningham MF. Preparing artificial latexes using a switchable hydrophilicity solvent. Green Chem, 2017, 19(8): 1889-1894.

[15] Liu Y, Jessop PG, Cunningham M, et al. Switchable surfactants. Science, 2006, 313(5789): 958-960.

[16] Liang C, Harjani JR, Robert T, et al. Use of CO₂-triggered switchable surfactants for the stabilization of oil-in-water emulsions. Energy Fuels, 2012, 26(1): 488-494.

[17] Arthur T, Harjani JR, Phan L, et al. Effects-driven chemical design: the acute toxicity of CO₂-triggered switchable surfactants to rainbow trout can be predicted from octanol-water partition coefficients. Green Chem, 2012, 14(2): 357-362.

[18] Qiao W, Zheng Z, Shi Q. Synthesis and properties of a series of CO₂ switchable surfactants with imidazoline group. J Surfactants Deterg, 2012, 15(5): 533-539.

[19] Fowler CI, Jessop PG, Cunningham MF. Aryl amidine and tertiary amine switchable surfactants and their application in the emulsion polymerization of methyl methacrylate. Macromolecules, 2012, 45(7): 2955-2962.

[20] Zhang Y, Guo S, Wu W, et al. CO₂-triggered pickering emulsion based on silica nanoparticles and tertiary amine with long hydrophobic tails. Langmuir, 2016, 32(45): 11861-11867.

[21] Harjani JR, Liang C, Jessop PG. A synthesis of acetamidines. J Org Chem, 2011, 76(6): 1683-1691.

[22] Cunningham MF, Jessop PG, Darabi A, et al. In carbon dioxide switchable polymers and processes in polymer reaction engineering. Macromol Symp, 2016, 370(1): 92-98.

[23] Veer SD, Katkar KV, Akamanchi KG. Sulfated tungstate catalyzed activation of nitriles: addition of amines to nitriles for synthesis of amidines. Tetrahedron Lett, 2016, 57(36): 4039-4043.

[24] Bae I, Han H, Chang S. Highly efficient one-pot synthesis of N-sulfonylamidines by Cu-catalyzed three-component coupling of sulfonyl azide, alkyne, and amine. J Am Chem Soc, 2005, 127(7): 2038-2039.

[25] Patai S, Rappoport Z. The chemistry of amidines and imidates, 1975, New York: Wiley 363-364.

[26] Caron S, Wei L, Douville J, et al. Preparation and utility of trihaloethyl imidates: useful reagents for the synthesis of amidines. J Org Chem, 2010, 75(3): 945-947.

[27] Scoggins MW. A rapid gas chromatographic analysis of diastereomeric diamines. J Chromatogr Sci, 1975, 13(3): 146-148.

[28] Oszczapowicz J, Raczyńska E. Amidines. Part 13. Influence of substitution at imino nitrogen atom on pK _a values of N ₁ N ₁-dimethylacetamidines. J Chem Soc Perkin Trans, 1984, 2(10): 1643-1646.

[29] Åke P, Alf R, Kurt T. Preparation and properties of N-monoalkylated imidic esters. Acta Chem Scand, 1969, 23(3): 818-824.

[30] Fulmer GR, Miller AJM, Sherden NH, et al. NMR chemical shifts of trace impurities: common laboratory solvents, organics, and gases in deuterated solvents relevant to the organometallic chemist. Organometallics, 2010, 29(9): 2176-2179.