A Protons Exchanged Montmorillonite Clay as an Efficient Catalyst for the Reaction of Isobutylene Polymerization

Abstract

The polymerization was performed under suitable conditions at isobutylene vaporization temperature (-7°C). Experiments revealed that polymerization induced by "H-Maghnite" proceed in bulk and in solution. In contrast to findings with methylene chloride CH 2 Cl 2 as a polar solvent, polymerization yields with hexane C 6 H 14 non-polar solvent is very significant.In bulk polymerization, Isobutylene conversion increases with increasing "H-Maghnite" proportion.

Polymerization of DL-Lactide induced by Protonated Montmorillonite clay as a solid catalyst: Mechanism study

“…The composition and the structure of Maghnite-H + were reported in a previous works 10,18 , in which we have demonstrated that 10 , the other peaks are related to the structure of Montmorillonite aluminum-oxygen octahedron and silicon-oxygen tetrahedron 10,20 . The comparison between the diffractograms of Maghnite ( figure 2(a) ) and Maghnite/Polymer mixture after the reaction ( figure 2 (b) ), shows that there are no significant changes on the cristallogaphic structure of Maghnite-H + after the reaction.…”

“…The spectra provide information about the local environment of the aluminum sites in Maghnite, two small bands of two tetra-coordinated AlO 4 (Al TD1 and AL Td2 ) at 58-60 ppm and 68-71 ppm, and another signal at 3-4 ppm attributed to octahedral AlO 6 (Al Oh ) 25 . AlO 4 sites in the maghnite structure are the consequence of isomorphic ions substitution within the silicate layers 10,[15][16][17] . Meanwhile, the 27 Al NMR spectra of Maghnite-H + and of Maghnite-H + /Polymer mixture after the reaction were closely identical, two very significant differences were observed in the 27 Al NMR spectra.…”

“…In recent years, the growth of the environmental requirements, have resulted in a demand for alternative catalytic processes. In this regard, many studies have been carried out on the development of new solid acids, such as "Keggin-type Heteropolycompounds" [5][6][7][8] or acidic clay catalysts [9][10][11] , to replace corrosives homogeneous acids and to resolve the problems related to the purification of the resulted polymers. Therefore, the replacement of classic homogeneous catalysts (such as Lewis acid) by heterogeneous system can offer many advantages: besides of the respect of green chemistry basis, heterogeneous catalysts give easier separation, possible higher product yields and mild reaction conditions 8 .…”

“…In our previous works, we have already reported about polymerization reactions catalyzed by Maghnite-H + , a proton exchanged montmorillonite clay. This new non-toxic available eco-catalyst exhibited higher efficiency via the cationic polymerization of vinylic and hetero-cyclic monomers [10][11][12][13][14][15][16][17][18] . The aim of this study is to elucidate the interactions between the monomer (D, L-Lactide) and the inorganic platelets of Maghnite occurring upon the reaction of polymerization.…”

Cationic Ring Opening polymerization of ε-caprolactam by a Montmorillonite Clay Catalyst

“…Montmorillonites, a class of inexpensive and noncorrosive solid acids, have been used as efficient catalysts for a variety of organic reactions. The reactions catalyzed by montmorillonites are usually carried out under mild conditions with high yields and high selectivities, and the workup of these reactions is very simple; only filtration to remove the catalyst and evaporation of the solvent are required, maghnite-H + can be easily recovered and reused, after it has separated from the polymer, it was rinsed with water and dried by heating to a temperature above 100 °C and finally crushed [19,20]. To ensure good performance, the Maghnite-H + can be reactivated with acid [21,22].…”