Identification of carboxylic acids: Use of N-methylpiperazine and N-phenylpiperazine

Duff, J. G.; Yung, D. K.; Brenner, R.A.; Wilson, Betty Jo; Racz, William J.

doi:10.1021/ed046p388

Cited by 2 publications

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References 2 publications

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“…Containing two nitrogen atoms in a piperazine molecule, piperazines usually show strong basicity and, acting as organic cations similar to quaternary ammonium salts, may have potential applications to the preparation of novel ILs. Because the reactions of N -alkylpiperazines and carboxylic acids were first introduced in 1969 by Duff et al, there are only few reports focused on these particular organic salts used as ILs. − Recently, a series of alkylpiperazinium-based salts have been synthesized in our group, and some of them have been investigated for practical use of fuel desulfurization. The aim of this work is to demonstrate the desulfurization performance of several halogen-free piperazinium-based RTILs, which are supposed to be environmentally friendly and are easy to be prepared from cheap materials.…”

Section: Introductionmentioning

confidence: 99%

Piperazinium-Based Ionic Liquids with Lactate Anion for Extractive Desulfurization of Fuels

Lü

Yue

et al. 2014

Energy Fuels

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Three kinds of piperazinium-based room-temperature ionic liquids (RTILs), namely, N-methylpiperazinium lactate ([C 1 pi][Lac]), N-ethylpiperazinium lactate ([C 2 pi][Lac]), and N,N′-dimethylpiperazinium dilactate ([C 1 C 1 pi][Lac] 2 ), have been synthesized by the direct reaction of N-alkyl-substituted piperazines and lactate acid. Together with 1,1,3,3tetramethylguanidinium lactate ([TMG][Lac]), they are employed as new extractants for removing aromatic sulfur compounds, thiophene (TS), benzothiophene (BT), dibenzothiophene (DBT), and 4-methyldibenzothiophene (4-MDBT), from various hydrocarbon fuels. The effects of the temperature, extraction time, and amount of ionic liquid (IL) on the sulfur removal are investigated systematically. The mutual solubility measurements show that the ILs are dissolved in n-heptane with the mass fraction less than 0.01 at 30 °C. The solubility values of 93 gasoline in the ILs are observed with the following sequence: [C 1 C 1 pi][Lac] 2 (0.007 in mass fraction) < [C 1 pi][Lac] (0.014 in mass fraction) < [TMG][Lac] (0.017 in mass fraction) < [C 2 pi][Lac] (0.070 in mass fraction), and the sulfur distribution coefficient follows the order: [TMG][Lac] (1.08 in mass fraction) > [C 2 pi][Lac] (0.98 in mass fraction) > [C 1 pi][Lac] (0.78 in mass fraction) > [C 1 C 1 pi][Lac] 2 (0.53 in mass fraction) for 93 gasoline. Selectivity between TS and toluene is observed higher than 4 with the following sequence: [TMG][Lac] (13.19 in mass fraction) > [C 1 pi][Lac] (10.59 in mass fraction) > [C 2 pi][Lac] (7.12 in mass fraction) > [C 1 C 1 pi][Lac] 2 ( 4.94 in mass fraction), revealing that these ILs are more preferable to extract TS than toluene from hydrocarbon fuels. The used ILs can be recycled without a significant decrease of desulfurization activity after extraction 5 times. These fundamental results hopefully provide useful information for future commercialization and practical desulfurization.

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