SHORT COMMUNICATION Acidic ionic liquid polymers: poly(bis-imidazolium-p-phenylenesulfonic acid) and applications as catalysts in the preparation of 1-amidoalkyl-2-naphthols Ananda S. Amarasekara 1 & Jennifer Nguyen 1 & Ashfaqur Razzaq 1 Received: 8 February 2016 /Accepted: 3 March 2017 /Published online: 10 March 2017 # Springer Science+Business Media Dordrecht 2017 Abstract A new class of polymeric acidic ionic liquids with imidazolium hydrogen sulfate and p-phenylene sulfonic acid units built into the main polymer chain were prepared by a simple two step method in 87–89% yield. These new poly- mers were characterized by elemental analysis, 1 H, 13 C NMR, FT-IR, TGA and GPC. The catalytic activity of sulfonic acid group functionalized ionic liquid polymers was demonstrated through the synthesis of 1-amidoalkyl-2-naphthols in 78–90% yield by condensation of 2-naphthol, benzaldehyde and am- ides without a solvent at 100 °C. Keywords Ionic liquid polymer . Sulfonation . Imidazolium . Sulfonic acid . 1-amidoalkyl-2-naphthol Introduction Ionic liquid (IL) polymers is an immerging group of smart materials. This new class of polymers has found applications in a number of areas such as: fuel desulfurization [1], GC stationary phases [2], electric field actuators [3], anion de- tectors [4], lithium-polymer batteries [5], gene-delivery vec- tors [6], gas separation membranes [7], conducting polymer coatings [8], electrospinable polymers [9] and dye sensitized solar cells [10, 11]. The polymerized acidic ionic liquid is a relatively unexplored sub-group in the polymeric ionic liq- uids arena and these acidic polymers can combine ionic liquid, acidic and polymer characteristics into a single mate- rial [12]. In the last three to four years a few research groups have synthesized polymeric compounds with acidic ionic liquid pendant groups attached to the main polymer struc- ture. These materials have been used in several applications such as acid catalysts, membranes and as electrolytes. Wang et al. have reported a synthesis of a poly(4-vinylpyridine) supported acidic ionic liquid catalyst and showed the incor- poration of polymer features into an acidic ionic liquid cat- alyst [13]. In this case they used the new polymer as a heterogeneous catalyst for the cyclocondensation reaction of anthranilamide with aldehydes under ultrasonic irradiation and produced the corresponding 2,3-dihydro-4(1H)- quinazolinones compounds [13]. In another example, acidic ionic liquid functionalized polymer (PDVB-SO 3 H- [C 3 vim][SO 3 CF 3 ]) is shown to possesses abundant nanoporous structures and capable of depolymerizing cellu- lose into sugars [14]. Yasuda et al. has prepared and used a diethylmethylammonium trifluoromethanesulfonate ([dema][TfO]) based polymeric acidic ionic liquid. A solid thin film containing [dema][TfO] was fabricated using sulfonated polyimide as a matrix polymer and they success- fully used this polymeric acidic ionic liquid thin film as a part of a composite membrane in a non-humidifying fuel cell [15]. Additionally, the acidic IL functionalized polymer- ic materials with imidazolium-SO 3 H, and pyridinium-SO 3 H as pendant groups have been used as catalysts for the bio- diesel synthesis from waste oils [16, 17]. Our interests in the applications of ionic liquids in bio- mass processing [ 18 – 22 ] and thermal properties of imidazolium ionic liquids [23] has led us to explore possible synthetic methods for the preparation of polymeric ionic liquids. In 2010 we reported the first synthesis of a polymer- ic ionic liquid with ionic liquid moieties in the main polymer chain, rather than as pendant groups, by simple * Ananda S. Amarasekara asamarasekara@pvamu.edu 1 Department of Chemistry, Prairie View A&M University, Prairie View, TX 77446, USA J Polym Res (2017) 24: 52 DOI 10.1007/s10965-017-1216-5