Piperazine Polymerization Catalyzed by Maghnite-H+

New polymers polypiperazines were synthesized in the presence of a non-toxic catalyst Maghnite-H+ from the addition of dihalogenated compounds such as 1,6-dichlorohexane and 1,2-dibromopropane to piperazine, after the comparative study of the polymerizations without and with this catalyst. The yields of the synthesis induced by Mahgnite-H+ are high compared with those of the uncatalyzed reactions. In our case, the effect of reaction time on the yield was studied by carrying out a series of experiments by maintaining the quantities of the reagents and varying the time t. On the other hand, polymerizations of piperazine are realized by maintaining the amounts of monomer, the time duration and varying the amount of Mahgnite-H+ in order to control the influence of the amount of this catalyst on the yield of the bulk polymerization of the piperazine. By constation, the yield grows either with the increase of reaction time, or by increasing the quantity of the catalyst. All products synthesized during the addition of dihalogenated compounds to piperazine were characterized by FT-IR spectroscopy (Perkin Elmer System), 1H-nuclear magnetic resonance (NMR) and 13C nuclear magnetic resonance (NMR) measurements were carried out on a 300 MHz Bruker NMR Spectrometer. Time (hours) 0.5 1.0 1.5 2.0 2.5 3.0 Yield (%) (a) 17 38 56 65 73 76 (b) 20 42 66 75 82 84 Table 1: Effect of time on the yield of piperazine polymerization with 1,6-dichlorohexane without (a) and with catalyst (b). Time (hours) 0.5 1.0 1.5 2.0 2.5 3.0 Yield (%) (a) 12.8 22 39 60.9 64 66 (b) 14 24 44 67.1 69.5 72 Table 2: Effect of time on the yield of piperazine polymerization with 1,2-dibromopropane without (a) and with catalyst (b).


Introduction
Piperazines are precursors of many polymers at high-value such as poly (methyl-para-piperazine-hydroxybenzoic acid), polyethylenes polypiperazines, polypiperazine phosphonamides, poly (iodideperfluorohexylpiperazine) etc. The importance of its use [1][2][3] is due to the chelating properties of tertiary nitrogen and to the presence of a stable cycle at six-ring.
The condensation of the piperazine with allyl chloride catalysed by Maghnite-H + was carried out by Hachemaoui to prepare allyl chloride [8]. It has also synthesized ammonium iodides by adding the diiodinated compounds to the piperazine [9]. On the other hand, the grafting of this monomer on a halide was done by Benhamou [10] at ambient temperature and in the presence of tetrahydrofuran. The new non-toxic initiator Maghnite-H + [11][12][13][14][15][16] has been used to prepare and study several kinds of polymers.

Materials
In our case we have carried out the addition of dihalogenated compounds on piperazine such as 1,6-dichlorohexane and 1,2-dibromopropane in the presence of Maghnite-H + . The choice of reaction with catalyst was made after obtaining good yields (Tables  1 and 2). We have carried out a series of experiments by maintaining the quantities of the reagents and varying the time t (Figures 1 and 2). The molecular structure of products of all reactions of piperazine with dihalogenated compounds was characterized by FT-IR spectroscopy (Perkin Elmer System), 1 H-nuclear magnetic resonance (NMR) and 13 C nuclear magnetic resonance (NMR) measurements were carried out on New polymers polypiperazines were synthesized in the presence of a non-toxic catalyst Maghnite-H + from the addition of dihalogenated compounds such as 1,6-dichlorohexane and 1,2-dibromopropane to piperazine, after the comparative study of the polymerizations without and with this catalyst. The yields of the synthesis induced by Mahgnite-H + are high compared with those of the uncatalyzed reactions. In our case, the effect of reaction time on the yield was studied by carrying out a series of experiments by maintaining the quantities of the reagents and varying the time t. On the other hand, polymerizations of piperazine are realized by maintaining the amounts of monomer, the time duration and varying the amount of Mahgnite-H + in order to control the influence of the amount of this catalyst on the yield of the bulk polymerization of the piperazine. By constation, the yield grows either with the increase of reaction time, or by increasing the quantity of the catalyst. All products synthesized during the addition of dihalogenated compounds to piperazine were characterized by FT-IR spectroscopy (Perkin Elmer System), 1 H-nuclear magnetic resonance (NMR) and 13 C nuclear magnetic resonance (NMR) measurements were carried out on a 300 MHz Bruker NMR Spectrometer.

Polymer preparation
Reaction of piperazine with 1,2-dichloropropane: 2 g of dry Maghnite are introduced into a two-necked flask, and 2.74 ml (3 × 10 -2 mol) of piperazine are added, with stirring at room temperature for 20 to 30 minutes. 0.974 ml (10 -2 mol) of 1,2-dichloropropane are poured, the mixture is left stirring for 2 hours. The reaction crude is washed with chloroform; the Maghnite is recovered by simple filtration on filter paper. The filtrate is then dried using a rotary evaporator. The product obtained is white with a yield of 96%.
Reaction of piperazine with 1,2-dibromopropane: 2 g of dry Maghnite are introduced into a two-necked flask, and 2.74 ml (3 × 10 -2 mol) of piperazine are added, with stirring at room temperature for 20 to 30 minutes. 1.045 ml (10 -2 mol) of 1,2-dibromopropane are poured, the mixture is left stirring for 2 hours. The reaction crude is washed with chloroform; the Maghnite is recovered by simple filtration on filter paper. The filtrate is then dried using a rotary evaporator. The product obtained is white in a yield of 80%.
Reaction of piperazine with 1,6-dichlorohexane: 2 g of dry Maghnite are added to a two-necked flask, and 0.913 ml (10 -2 mole) of piperazine are added with stirring at room temperature for 20 to 30 minutes. 1.45 ml (10 -2 mol) of 1,6-dichlorohexane are poured, the mixture is left stirring for 2 hours. The reaction crude is washed with chloroform; the Maghnite is recovered by simple filtration on filter paper. The filtrate is then dried using a rotary evaporator. The product obtained is viscous, and of a light yellow color with a yield 87%.
Reaction of piperazine with 1,6-dibromohexane: 2 g of dry Maghnite are introduced into a two-necked flask, and 2.74 ml (3 × 10 -2 mol) of piperazine are added, with stirring at room temperature for 20 to 30 minutes. 1.54 ml (10 -2 mol) of the 1,6-dibromohexane are poured, the mixture is left stirring for 2 hours. The reaction crude is washed with chloroform; the Maghnite is recovered by simple filtration on filter paper. The filtrate is then dried using a rotary evaporator. The product obtained is light yellow in color with a yield of 72%.
Reaction of piperazine with dichloromethane: 2 g of dry Maghnite are introduced into a two-necked flask and 2.74 ml (3 × 10 -2 mol) of piperazine are added, with stirring at room temperature for 20 to 30 minutes. 0.974 ml (10 -2 mol) of 1,2-dichloropropane are poured, the mixture is left stirring for 2 hours. The reaction crude is washed with chloroform; the Maghnite is recovered by simple filtration on filter paper. The filtrate is then dried using a rotary evaporator. The product obtained is white with a yield of 80%.
Reaction of Piperazine with dibromomethane: 2 g of Maghnite are introduced into a two-necked round-bottomed flask, dried in an oven for 24 hours, allowed to cool to room temperature and then 2.739 ml (3 × 10 -2 mol) of piperazine are added, and after stopping the heating, 7.376 × 10 -2 ml (10 -2 mol) of dibromomethane are added. The mixture is left stirring for 2 hours. The crude reaction product is washed with chloroform; the Maghnite is recovered by simple filtration on filter paper. The filtrate is then dried with rotary evaporator; a residue is obtained which is washed. The yield is 60%.

Characterization of product (3) 1 H NMR:
An investigation was devoted to the analysis of the polymer (3) by 1 H NMR spectroscopy at 300 MHz (Table 3).
Characterization of product (3) 13 C NMR: An investigation was devoted to the analysis of the polymer (3) by 13 C NMR spectroscopy (Table 3a). Table 3b.

Conclusion
This present work shows that piperazine polymerization was induced by proton exchanged montmorillonite clay called Maghnite-H + with an important yield. These polypiperazine were produced by very simple procedure, through simple filtering, the clay was separated from reaction mixture.