Pilot Plant Study on the Polymerization of Isobutene Using Silica-Supported Methylaluminoxane

Abstract

Pilot plant scale studies on the polymerization of isobutene in n-hexane, induced by silica-supported methylaluminoxane and 2-bromobutane, were conducted in a stirred 7.5 L kettle reactor. Experimentation involved batch style reaction for both single and multiple/sequential runs. Conversion to the polymer was quantitative in all instances, and polymer molecular weights (MWs) are quite favorable for the reaction temperatures employed. Additionally, polymerization was well-behaved, giving rise to a consistent product from one run to another and tests show that the system is potentially suitable for continuous production methods. Due to the heterogeneous nature of the initiator system, high-purity polyisobutene was obtained by simple filtration of the reaction mixture followed by volatilization of solvent.

Highly exo‐olefinic polyisobutene synthesized using a recyclable acid

“…12,17,18 The corresponding author has focused on green cationic polymerizations for more than 20 years with emphasis on both isobutene and terpenes. [19][20][21] This includes aqueous polymerizations [22][23][24][25] as well as soluble 26,27 and heterogeneous [28][29][30][31] initiator systems that operate in nonpolar solvents at high T. Recently, the main goal of our group has been to develop initiator systems comprised of safer acids that function as true catalysts 25,27,31 and operate at ambient T in nonpolar media or in the absence of solvent. Although many researchers have claimed their polymerizations to be catalytic [32][33][34][35][36][37][38][39][40][41][42] only three examples of catalytic cationic polymerizations have actually been disclosed in the peer reviewed literature to date.…”

Indefinitely active aqueous cationic polymerizations, part I: Low cost, recyclable initiator systems

“…[73,74,79] HPAs have been used as initiators of cationic polymerization; [83,86,87,89,[91][92][93][94][95][96][97][98][99][100][101] however, their MW-T profiles are substandard, and they are not cost competitive to traditional LAs (e.g., BF 3 ). [7] As part of earlier investigations on supported methylaluminoxane [7,8,[102][103][104] and heterogeneous PFLA [105] based initiator systems, we also studied activated forms of HPAs as solid acid initiators with limited success. [106] Given our track record of devising aqueous cationic polymerizations, we shifted our attention to water soluble HPAs as the heteropoly anion may exhibit a high enough degree of lipophilicity to transit into a suspended monomer droplet.…”

“…HPAs have been used as initiators of cationic polymerization; however, their MW‐T profiles are substandard, and they are not cost competitive to traditional LAs (e.g., BF 3 ) . As part of earlier investigations on supported methylaluminoxane and heterogeneous PFLA based initiator systems, we also studied activated forms of HPAs as solid acid initiators with limited success…”