Catalytic Hydrogenations in Microemulsion Systems with Rh-TPPTS: Partial Hydrogenation of Sunflower Oil

Abstract

The effect of the P/Rh ratio and the surfactant concentration on the partial hydrogenation of sunflower oil in Triton X-100 microemulsion systems with the watersoluble catalyst complex Rh-TPPTS has been studied. An unusual hindering effect of the surfactant on the production of elaidic acid and stearic acid as the oil is hydrogenated was observed. When increasing the concentration of Triton X-100 in the reaction medium from 3 to 15 wt%, the content of elaidic acid and stearic acid were lowered 21 and 34%, respectively. The maximum content of oleic acid was attained when the concentration of Triton X-100 was 15 wt%, obtaining a high content of 51.8% of oleic acid. When the ligand/metal ratio was higher, the reaction was slower but more selective to oleic acid. The Rh-TPPTS catalyst could be recycled up to 3 times after hydrogenation of sunflower oil by extracting the oil phase of a three-phase microemulsion system, observing a continuous deactivation of the catalyst.

Toward Water-Based Recycling Techniques: Methodologies for Homogeneous Catalyst Recycling in Liquid/Liquid Multiphase Media and Their Implementation in Continuous Processes

“…There are examples in the past including, for example, hydrogenations. 95,96 The topic of reactions in microemulsion systems has been recently reviewed by Schwarze et al 97 The hydroformylation of long chain olefins with the help of surfactants has been under investigation within the last 15 years. 98 The group of Schomacker has been able to successfully develop a system for the hydroformylation of 1-dodecene in microemulsion media.…”

“…The hydrophilic catalyst remains in the water phase and can be reused. There are examples in the past including, for example, hydrogenations. , The topic of reactions in microemulsion systems has been recently reviewed by Schwarze et al…”

Microemulsion systems for catalytic reactions and processes

“…Hamerla et al 36 showed that for the hydroformylation of 1-dodecene by Rh/SX higher reaction rates can be obtained when the reaction is performed in a triphasic microemulsion instead of W1 or W2 systems. Milano et al 35 studied the hydrogenation of sunflower oil and recycled the Rh/TPPTS catalyst up to three times by extracting the oil phase of a three-phase microemulsion system.…”

d-Xylose-based surfactants: Synthesis, characterization and molecular modeling studies

“…13 C NMR (DMSO-d 6 , 62.9 MHz): 14.3 (C 18 0 ), 23.6 (C 17 0 ), 25.9 (C 16 0 ), 27.9 (C 15 0 ), 30. 3, 30.4, 30.5, 30.6 (C 14 (1)(2)(3)(4)(5) were acetylated in the presence of acetic anhydride (12 equiv) and sodium acetate (1 equiv) for 24 to 72 h at 50 8C under stirring. The reaction was followed by TLC.…”

“…The use of transfer agents or surfactants, which are key compounds to the organized molecular systems can partially overcome these difficulties, while improving the catalytic activity [4]. Concerning hydrogenation processes, for example, the Rh-catalyzed hydrogenation of unsaturated substrates was one of the first widely described studies [5][6][7].…”