Production of p‐toluenesulfonic acid by sulfonating toluene with gaseous sulfur trioxide

Abstract

Toluene was sulfonated by gaseous sulfur trioxide to prepare p-toluenesulfonic acid. The effects of reaction temperature and toluene conversion on the isomer selectivities and the dynamic viscosity of the reaction mixture in a well-stirred tubular glass reactor of 4 cm diameter and 16 cm height were investigated. Lower selectivity to the m-isomer was obtained at lower reaction temperature and lower conversion of toluene, whereas the selectivity to the p-isomer seemed to be less affected by these parameters. With the increase in toluene conversion a sharp increase in viscosity of the reaction mixture was observed, which was attributed to the saturation of the toluenesulfonic acids dissolved in toluene. A pilot-scale stainless steel jet loop reactor (JLR) of 0.3 m diameter and 4 m height with an external cooler was constructed and used for the continuous sulfonation of toluene. It was found that the JLR was very effective for the fast removal of the large amount of reaction heat, and selectivities to the p-isomer around 85% and to the m-isomer below 1.2% were obtained.

p-Toluenesulfonic Acid-Based Deep-Eutectic Solvents for Solubilizing Metal Oxides

“…The synthesis of ptsa is performed via direct sulfonation of toluene . It is used in a very broad range of applications, e.g., as a catalyst, detergent solubilizer, resin hardener, in pharmaceuticals, or as an intermediate in the production of saccharine. , In the literature, different ptsa-based DESs have already been reported but barely characterized, e.g., ptsa:choline chloride at a molar ratio of 1:1, ptsa:benzyltrimethylammonium chloride at a molar ratio of 2.3:1, ptsa:allyltriphenylphosphonium bromide at a molar ratio 3:1, or ptsa:n,n-diethylenethanol ammonium chloride. − In this paper, combinations of ptsa with different HBAs were prepared in a 1:1 molar ratio in order to obtain ptsa-based eutectic mixtures. The mixtures that resulted in DESs were physicochemically characterized.…”

Droplet Coalescence Phenomena during Liquid–Liquid Heterogeneous Reactions in Microreactors

“…Conventional reactors, including tank reactors, thin-film reactors, falling film reactors, and jet loop reactors, have been employed in liquid–liquid heterogeneous reaction processes. , However, these reactors have some disadvantages especially when they are applied for highly exothermic and fast reaction systems. Insufficient heat- and mass transfer capabilities of these reactors may give rise to obvious gradients of concentration and temperature inside reactors, which may lead to low reaction rate, local overheating of reactors, formation of many impurities, or even runaway of the reaction. , …”