Ion exchange resin as catalyst

A series of experiments was conducted to form monoethyl and diethyl succinate using either sulfuric acid or acidic ion-exchange resin as catalysts. The esterification of succinic acid is modeled as a simple series reaction sequence. 

Sabou R, Hoelderich WF, Ramprasad D, Weinand R (2005) Synthesis of 7-Hydroxy-4-methylcoumarin via the Pechmann reaction with Amberlyst ion-exchange resins as catalysts. J Catal 232 34-37... 

MTBE is a well known enhancer of the number of octanes in gasoline and as excellent oxygentated fuel additives that decrease carbon monoxide emissions. Therefore, MTBE has been one of the fastest growing chemicals of the past decade. MTBE is produced by reacting methanol with isobutylene from mixed-C4 stream liquid phase over a strong acid ion-exchange resin as catalyst. An excess of methanol is used in order to improve the reaction conversion. This excess has to be separated from the final product. The pervaporation technique, more energy efficient and with lower cost process, has been proposed as alternative to distillation [74],... 

The esterification of acetic acid with ethanol using sulfonic ion-exchange resins as catalyst/selective sorbent was studied by Mazzotti et al. [164]. The authors developed a detailed mathematical model, which was able to predict correctly the system s behavior. They succeeded in obtaining 100% conversion of acetic acid in addition to a complete separation. Several other studies involving enzymatic reactions were also carried out and will be presented in more detail in the next section. 

Hydrolysis of inulin has already been performed in the presence of a zeolite, namely the zeolite LZ-M-8.[11] This catalyst has been found to be extremely selective towards hydrolysis compared with fructose decomposition, thus illustrating the superiority of the zeolite over sulfuric acid or ion-exchange resins as catalysts. As an example, a 96% yield in fmctose was obtained after 15 min at 130 °C starting from 2 ml of a 0.257 mol L 1 inulin solution and 0.25 g of zeolite. 

Limbeck et al. [34] have studied the kinetics of this irreversible reaction at macroporous acidic ion exchange resins as catalysts. In this reaction, the byproduct water has a significant affinity with the catalyst, and thus severely inhibits the catalytic reaction. Therefore, these authors proposed the following rate expression ... 

Effective catalysts for preparing the polyformals were p-toluenesulfonic acid, camphorsulfonic acid, methanedisulfonic acid, and perchloric acid. Various other acidic compounds were evaluated as catalysts with tetramethylcyclobutanediol. In these experiments, 0.5 to 1.0 gram of acidic compound per mole of tetramethylcyclobutanediol was normally added. If insufficient water was obtained, more catalyst was added. If the prepolymer was obtained but an appreciable amount of brown color was present, less catalyst was then used. Compounds which did not catalyze the reaction (no water obtained) were phosphoric acid, zinc chloride, trifluoroacetic acid, and heptafluorobutyric acid. Incomplete reactions (insufficient water) took place with concentrated hydrochloric acid, concentrated nitric acid, zinc fluoroborate, or Amberlite IRC-50 ion exchange resin as catalyst. A prepolymer was obtained when boron trifluoride etherate was used, but buildup did not take place in the solid phase (catalyst probably too volatile). Brown or speckled-brown polymers (after solid-phase buildup) were obtained with catalysts containing sulfonic acid groups (benzenesulfonic, dodecylbenzenesulfonic, sulfo-acetic, methanetrisulfonic, sulfuric, p-toluenesulfonic, camphorsulfonic, and methanedisulfonic acids). To obtain white polymers from tetramethylcyclobutanediol it was necessary to treat the solvent and prepolymer reaction mixture as previously described. (White polyformals were obtained from the other diols without this treatment.)... 

M. M. Sharma, Some novel aspects of cationic ion-exchange resins as catalysts, Reactive and Functional Polymers 26, 3-23 (1995). 

Related topics include the use of ion exchange resins as catalysts in reactors (Section 16.11.6.32), liquid-solid fixed bed reactors (Sections 16.11.6.14 and 16.11.6.15), and adsorption-liquid (Section... 

Arrad, 0., and Y. Sasson, Commercial Ion Exchange Resins as Catalysts in Solid-Solid-Liquid Reactions, J. Org. Chem., 54, 4493 (1989). 

Chakrabarti, A Sharma, M Cationic ion exchange resins as catalysts. React. Polym. 1993, 20, 1-45. 

The effect of substituent groups was also studied. In a series of N-substituted hydrazones, PhNRN CMeEt, cyclization proceeded with increasing difficulty in the series R = H, Me, Et, Ph this was ascribed to the effect of increasing steric hindrance [12]. From acetaldehyde phenylhydrazones with methoxy substituents on the aromatic ring, yields were poor, which was attributed to decomposition of the substrate to non-volatile products on the alumina catalyst surface [13]. In contrast, with an acidic ion-exchange resin as catalyst, higher yields were obtained with the 4-methoxy derivative than with the 4-nitro this was interpreted as the effect of methoxy in facilitating adsorption on the resin [14]. 

The fuel ether MTBE is synthesized by the liquid-phase reaction of isobutene (IB) and methanol (MeOH) using macroreticular sulfonic acid ion-exchange resins as catalysts. The stoichiometric equation is given by... 

Isopropanol (2-propanol) is now manufactured largely by direct hydration of propylene over supported phosphoric acid catalysts at about 180°C and 50-60 atm., though Deutsche Texaco has commercialized the use of an ion-exchange resin as catalyst. 

P. Hodge, Paper presented at SCI Meeting on Ion Exchange Resins as Catalysts, London, June 1994 also in Macromolecules 1991 (ed J. Kahovec), VSP, Utrecht, 1993, p. 441. 

Chakrabarti, A., Sharma, M. M. (1993). Cationic ion-exchange resins as catalyst. Reactive Polymers, 20, 1—45. 

MTBE is commercially produced by the reaction of isobutylene with methanol in the presence of an acidic ion-exchange resin as catalyst, usually in the liquid phase and at temperatures below 100°C. A typical catalyst is sulfonated styrene/divinylbenzene resin catalyst. Other solid acid catalysts such as bentonites are also effective and other novel catalysts have recently been discovered. Isobutylene is obtained from field butane by initial isomerization of n-butane to isobutane, followed by dehydrogenation to isobutylene. Commercial preparations of MTBE are 95.03 to 98.93% pure. Impurities are methanol (<0.43%), t-butyl alcohol (<0.80%), and diisobutylene (<0.25%). 

Patel, D. B. Saha (2007) Heterogeneous kinetics and residue curve map (RCM) determination for synthesis of n-hexyl acetate using ion-exchange resins as catalysts. Industrial Engineering Chemistry Research, 46, 3157-3169,ISSN 0888-5885. 

In 1949 Harold Cassidy of Yale University took the next step from ion-exchange resins as catalysts, to resins which could function as reagents by accepting or donating electrons. He essentially created the field of redox pol3rmers and was quickly joined by the efforts of Manecke in Germany (1953). While this concept has remained dormant since Cassidy and Kun s book, "Oxidation Reduction Polymers" was published in 1965, it has gained new currency since... 

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