Sulfonation of solid polystyrene using gaseous sulfur trioxide

Abstract

Kinetics of the heterogeneous sulfonation of polystyrene (PS) beads using gaseous SO3 was investigated. Scanning electron microscopy (SEM) and electron diffraction scattering spectroscopy (EDS) was employed to study the kinetics of diffusion of SO3 into the PS particles. The diffusion of SO3 through the barrier of sulfonated polystyrene (SPS) on the beads surface was the primary parameter determining the rate and the yield of the sulfonation reaction. The measurement of the time dependence of the thickness of sulfonated layer formed on the solid PS surface provided for the hypothesis that the sulfonation in heterogeneous phase was diffusion controlled. Diffusion coefficients of SO3 in PS at −5°C, 22°C, and at 50°C and activation energy of SO3 diffusion to the solid PS were determined from these experimental data assuming in the first approximation a simple diffusion unaffected by the ongoing sulfonation reaction. The experimental data were fitted using Johanson‐Mehl‐Avrami‐Jerofyeev‐Kolgomorov's equation to obtain an overall rate constant of heterogeneous sulfonation on solid PS surface. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers

Síntese de poliestireno sulfonado para aplicações no tratamento de água produzido a partir de copos e bandejas descartadas de poliestireno

“…A escolha das condições para sulfonação é feita considerando 3 fatores: nível de sulfonação, tipo de isômero formado e rendimento da reação. 8 O método mais freqüentemente empregado em meio homogêneo é a sulfonação do PS solubilizado em dicloroetano e o emprego do acetilsulfato, produzido pela reação do anidrido acético com o ácido sulfúrico concentrado, como agente sulfonante. 8 Poliestireno sulfonado com um elevado grau de sulfonação também pode ser obtido através da rota heterogênea.…”

“…8 O método mais freqüentemente empregado em meio homogêneo é a sulfonação do PS solubilizado em dicloroetano e o emprego do acetilsulfato, produzido pela reação do anidrido acético com o ácido sulfúrico concentrado, como agente sulfonante. 8 Poliestireno sulfonado com um elevado grau de sulfonação também pode ser obtido através da rota heterogênea. Neste caso, pode-se empregar o PS em pó adicionado em ácido sulfúrico concentrado (agente sulfonante) e sulfato de prata como catalisador.…”

A simple and efficient synthesis protocol for sulfonation of nitrobenzene under solvent-free conditions via a microreactor

“…The sulfonation with chlorosulfuric acid can also create an acid disposal problem due to the generation of hydrogen chloride during the reaction process. 8 SO 3 as the sulfonating agent has some distinctive advantages compared with other sulfonating agents, such as high activity, fast reaction rate, high atom economy due to direct addition of SO 3 group, low material cost and minimal waste acid generation. Thus, SO 3 sulfonation is a clean and efficient process and has been extensively performed in chemical industry.…”

“…The mass and heat transfer coefficients in microreactors are larger than those in conventional reactors by two orders of magnitude. 19,20 The sulfonation of toluene with a gas mixture of SO 3 and N 2 as the sulfonating agent has been investigated in a microreactor system by Mü ller and his co-workers. 21 They found that high selectivity was obtained with precise temperature control and high pressure resistance of the microreactor at a SO 3 : toluene molar ratio of 0.05-0.15.…”

“…[3][4] Sulfur trioxide (SO 3 ), oleum, sulfuric acid and chlorosulfuric acid are the general sulfonating agents and of high industrial importance due to the high availability and low cost of these reagents. 5 However, the sulfonation with sulfuric acid or oleum is an equilibrium process due to hydrolysis in produced water.…”