Thermal deactivation of strong-acid ion-exchange resins in water

Abstract

The thermal deactivation in water of several poly(styrene-divinylbenzene-sulfonic acid) resins in the hydrogen-ion form has been measured in a fixed-bed flow reactor at temperatures between 420 and 480 K. The deactivation is caused by the removal of sulfonic acid groups from the polymer matrix, giving sulfuric acid. The removal of sulfonic acid groups is found to be catalyzed by hydrogen ions, which in the present case originate from the acid groups in the resin. Two types of -S03H groups are present in the resins, showing widely differing rates of decomposition. The reaction by which the more stable -S03H groups (about 90% of the initial resin capacity) decompose has an activation energy of approximately 120 kj/mol for most resins tested. The resin was the most stable resin tested at the highest temperatures in the range studied. In the lower range the resin Dowex HCR-W X8 is the most stable one.

A Novel Sulfonated Carbon Composite Solid Acid Catalyst for Biodiesel Synthesis

“…4). The deactivation characteristics of P-SO 3 H were similar to those of other acidic resins with sulfonic acid groups [28,29], deactivating due to desulfonation. Thus, the stable catalytic performance for P-C-SO 3 H must be related to the integrated carbon-polymeric matrix precursor.…”

“…Depending on sulfonation conditions, the reported acid density of sulfonated carbons can be in the range of 0.48-1.74 mmol/g, a number higher than what has been reported for inorganic solid acids like SZ (0.1-0.5 mmol/g) [17], but lower than the acid density of commercially available strong acidic resins, such as Amberlyst-15 (4.7 mmol/g) [17]. Unlike sulfonicacid resins, sulfonated polycyclic aromatic carbons should be more resistant to desulfonation [28,29] as a result of the stabilization effect of the electron-withdrawing force that polycyclic aromatic hydrocarbons exert on bonded sulfonic groups. Hence, added stability is another appealing aspect of sulfonated carbon materials in addition to low cost.…”

Thermal Degradation Studies of Some Strongly Acidic Cation Exchange Resins

“…Hence, knowledge of the thermal behavior of cation exchange resins is necessary. Abundant data exist on the thermal degradation of anion exchange resins [23][24][25] and on carboxylic cationites with low acidity [26][27]; literature seems to offer relatively poor information on polystyrene-divinylbenzene sulfonic cationites [28][29][30][31][32][33]. Therefore, in the present investigation thermal degradation of strongly acidic sulfonic cationites was performed to understand the degradation steps and to compare the relative thermal stability.…”

Evaluation of strongly acidic ion‐exchange catalysts and the desulfonation study in the isobutylene dimerization reaction

“…Water could be generated from the reverse reaction of TBA at high temperatures. It is also known that desulfonation reaction is a hydrolysis reaction (Scheme ) 16. Therefore, TBA can be a source of desulfonation in the C4 dimerization process.…”

“…Deactivation of catalysts is also very common in industry production. There are many mechanisms that can cause catalyst deactivation including pore blockage due to the formation of polymers and/or desulfonation caused by high temperature in the presence of water or other organic media 14–16. Of course, the presence of metal cations in feed will also cause catalyst deactivation 17, 18…”