Cation exchange resin catalyst

Gupta and Douglas [AIChE J., 13 (883), 1967] have studied the catalytic hydration of isobutylene to f-butanol, using a cation exchange resin catalyst in a stirred tank reactor. 

The effect of the mode of heating was also studied in heterogeneously catalyzed esterification of acetic acid by isopentyl alcohol in the presence of Amberlyst-15 cation exchange resin catalyst [38], Scheme 10.2. 

I PA could always be made by direct hydration, but the severe operating conditions (high pressures and temperatures) and puny yields had always limited the economic enthusiasm for the process. Then catalysis research paid off with the development of a sulfonated polystyrene cationic exchange resin catalyst, a mouthful in itself. The breakthrough permitted reduced pressures and temperatures without loss of yield. The catalyst works in the vapor phase, the liquid phase, and the mixed phase. 

Mixtures of organic solvent and water have also been studied (Scheme 11). hi this context, Watanabe and coworkers studied the catalytic dehydration of fructose to HMF at 150°C in acetone-water mixtures and in the presence of a cation-exchange resin catalyst (Dowex 50wx8-100) [92]. The use of acetone-water (70 30 w/w) as reaction medium resulted in a yield of HMF of 73% at 94% conversion. Moreover, under these conditions, the catalyst was stable for at least five catalytic runs. Assistance of microwave not only increased the selectivity to HMF but also had a beneficial effect on the reaction rate. In this context, Gaset et al. studied the activity of Lewatit SPC-108 (cation-exchange resin) in a mixture of organic solvent (MIBK or diethyl ketone or benzonitrile or butyronitrile or dichlor-oethylether or nitropropane) and water (from 1/7 to 1/12 by volume) at a temperature around 85-90°C Under these conditions, HMF has been obtained with a yield of 70-80% [93, 94]. 

A mixed-phase reaction using a cation exchange resin catalyst... 

Description Acetone and excess phenol are reacted in a BPA synthesis reactor (1), which is packed with a cation-exchange resin catalyst. Higher acetone conversion and selectivity to BPA and long lifetime are characteristic of the catalyst. These properties reduce byproduct formation and catalyst volume. Unreacted acetone, water and some phenol are separated from the reaction mixture by distillations (2-4). Acetone is recycled to the BPA reactor (1) water is efficiently discharged phenol is mixed with feed phenol and purified by distillation (5). The crude-product stream containing BPA, phenol and impurities is transferred to the ciystallizer (6), where ciystalline product is formed and impurities are removed by the mother liquor. Sep-... 

As sulfur-containing organic molecules are known catalyst poisons because of strong adsorption, acylation of thioethers is difficult to obtain. The reaction between thioanisole and AAN can, however, be performed in the presence of ion-exchange resins that are more robust to deactiva-tion. The process is carried out in a Parr autoclave in 1,2-dichloro-ethane at 70°C. Under these conditions, other acid catalysts such as sulfated zirconia and KIO clay do not show any noticeable activity. Only the cation exchange resin catalysts, which contain Bronsted sites, are effective. Among these, Amberlyst-15 shows maximum conversion because it... 

The third step is the conversion of 1,4 diacetoxybutane to l-acetoxy-4-hydroxybutane by hydrolysis using a cation exchange resin catalyst. The chemistry is shown in Eq. (12) ... 

Son, S. M., Kimura, H., Kusakabe, K. (2011). Esterification of oleic acid in a three-phase, fixed-bed reactor packed with a cation exchange resin catalyst. Bioresource Technology, 102 2), 2130-2132. 

The reaction mechanism and kinetics of the MTBE synthesis from methanol and isobutylene have been studied over the commercial Amberlyst 15 cation-exchange resin catalyst. An activation energy of 71.2 kJ/mol was reported by Ancillotti et aL [127] for the forward reaction, whereas Gicquel and Torek [128] reported a value of 82.0 kJ/moL For the reverse reaction an activation ener of 122.6 kJ/mol has been reported [128]. The kinetics of the reaction are very dependent on the olefin and alcohol concentration. Ancillotti et aL [129] showed that the initial rate of synthesis is zero order in methanol at methanol-isobutylene ratios > 1. Most commercial processes operate at close to the stoichiometric ratio, and the rate is first order in isobutylene under these conditions. Ancillotti et aL [129] suggested that the effect of alcohol-olefin ratio can be e q)lained in terms of the equilibrium reaction... 

Hanika et al. (2003) investigated the esterification of acetic acid and butanol in a trickle bed reactor, packed with a strong acid ion- exchange resin (Purolite 151) at 343 K - 393 K. Experimental data illustrate the benefit of simultaneous esterification and partial evaporation of the reaction products in the multi-functional trickle bed reactor. In case of total wetting of the catalyst bed, contact of vaporized products (ester and water) with catalyst was naturally limited and thus, the backward reaction i.e. ester hydrolysis was suppressed. This phenomenon shifted the chemical equilibrium conversion to high values. Saletan (1952) obtained quantitative reaction rate data for the formation of ethyl acetate from ethanol and acetic acid in fixed beds of cation exchange resin catalyst. The complex interaction of diffusion and reaction kinetics within the resin, which determine over-all esterification rate, has been resolved mathematically. 

The exchange resins 6nd application in (i) the purification of water (cation-exchange resin to remove salts, followed by anion-exchange resin to remove free mineral acids and carbonic acid), (ii) removal of inorganic impurities from organic substances, (iii) in the partial separation of amino acids, and (iv) as catalysts in organic reactions (e.g., esterification. Section 111,102, and cyanoethylation. Section VI,22). 

Direct, acid catalyzed esterification of acryhc acid is the main route for the manufacture of higher alkyl esters. The most important higher alkyl acrylate is 2-ethyIhexyi acrylate prepared from the available 0x0 alcohol 2-ethyl-1-hexanol (see Alcohols, higher aliphatic). The most common catalysts are sulfuric or toluenesulfonic acid and sulfonic acid functional cation-exchange resins. Solvents are used as entraining agents for the removal of water of reaction. The product is washed with base to remove unreacted acryhc acid and catalyst and then purified by distillation. The esters are obtained in 80—90% yield and in exceUent purity. 

Deamidation of soy and other seed meal proteins by hydrolysis of the amide bond, and minimization of the hydrolysis of peptide bonds, improves functional properties of these products. For example, treatment of soy protein with dilute (0.05 A/) HCl, with or without a cation-exchange resin (Dowex 50) as a catalyst (133), with anions such as bicarbonate, phosphate, or chloride at pH 8.0 (134), or with peptide glutaminase at pH 7.0 (135), improved solubiHty, whipabiHty, water binding, and emulsifying properties. 

Acidic Cation-Exchange Resins. Brmnsted acid catalytic activity is responsible for the successful use of acidic cation-exchange resins, which are also soHd acids. Cation-exchange catalysts are used in esterification, acetal synthesis, ester alcoholysis, acetal alcoholysis, alcohol dehydration, ester hydrolysis, and sucrose inversion. The soHd acid type permits simplified procedures when high boiling and viscous compounds are involved because the catalyst can be separated from the products by simple filtration. Unsaturated acids and alcohols that can polymerise in the presence of proton acids can thus be esterified directiy and without polymerisation. 

Although catalytic hydration of ethylene oxide to maximize ethylene glycol production has been studied by a number of companies with numerous materials patented as catalysts, there has been no reported industrial manufacture of ethylene glycol via catalytic ethylene oxide hydrolysis. Studied catalysts include sulfonic acids, carboxyUc acids and salts, cation-exchange resins, acidic zeoHtes, haUdes, anion-exchange resins, metals, metal oxides, and metal salts (21—26). Carbon dioxide as a cocatalyst with many of the same materials has also received extensive study. 

The choice of catalyst is based primarily on economic effects and product purity requirements. More recentiy, the handling of waste associated with the choice of catalyst has become an important factor in the economic evaluation. Catalysts that produce less waste and more easily handled waste by-products are strongly preferred by alkylphenol producers. Some commonly used catalysts are sulfuric acid, boron trifluoride, aluminum phenoxide, methanesulfonic acid, toluene—xylene sulfonic acid, cationic-exchange resin, acidic clays, and modified zeoHtes. 

Esterification. Extensive commercial use is made of primary amyl acetate, a mixture of 1-pentyl acetate [28-63-7] and 2-metliylbutyl acetate [53496-15-4]. Esterifications with acetic acid are generally conducted in the Hquid phase in the presence of a strong acid catalyst such as sulfuric acid (34). Increased reaction rates are reported when esterifications are carried out in the presence of heteropoly acids supported on macroreticular cation-exchange resins (35) and 2eohte (36) catalysts in a heterogeneous process. Judging from the many patents issued in recent years, there appears to be considerable effort underway to find an appropriate soHd catalyst for a reactive distillation esterification process to avoid the product removal difficulties of the conventional process. 

Catalysts. The choice of the proper catalyst for an esterification reaction is dependent on several factors (43—46). The most common catalysts used are strong mineral acids such as sulfuric and hydrochloric acids. Lewis acids such as boron trifluoride, tin and zinc salts, aluminum haHdes, and organo—titanates have been used. Cation-exchange resins and zeoHtes are often employed also. 

Ethyl Acetate. The esterification of ethanol by acetic acid was studied in detail over a century ago (357), and considerable Hterature exists on deterrninations of the equiUbrium constant for the reaction. The usual catalyst for the production of ethyl acetate [141-78-6] is sulfuric acid, but other catalysts have been used, including cation-exchange resins (358), a- uoronitrites (359), titanium chelates (360), and quinones and their pardy reduced products. 

Hydration and dehydration employ catalysts that have a strong affinity for water. Alumina is the principal catalyst, but also used are aluminosihcates, metal salts and phosphoric acid or its metal salts on carriers, and cation exchange resins. 

Other possibilities for practical application of resin catalysis include some organic reactions involving addition, cyclization, and structural rearrangement. Increased stability and specific control of structure has led to the increased use of cation exchange resins as catalysts. As in the case of cation exchange resins many... 

The rate of hydrolysis of sarin on Dowex-50 cation exchange resin is insensitive to the stirring rate. However, with a more active catalyst (Amberlite-IRA 400), the rate constant at 20°C was 5.3, 7.5, and 8.5 h at 60,800 and 1000 revolutions/min , respectively, suggesting that film diffusion was the rate-limiting. step. Thus, the mechanism of the rate-limiting step depends on the nature of the catalyst [34]. 

In the liquid-phase process, high pressures in the range of 80-100 atmospheres are used. A sulfonated polystyrene cation exchange resin is the catalyst commonly used at about 150°C. An isopropanol yield of 93.5% can be realized at 75% propylene conversion. The only important byproduct is diisopropyl ether (about 5%). Figure 8-4 is a flow diagram of the propylene hydration process. ... 

Hammet and collaborators140, 141 studied in more detail the hydrolysis of aliphatic esters with a cation-exchange resins as catalyst. They found that replacement of 70% of the hydrogen ions in a crosslinked polystyrenesulfonic add by cetyl-trimethylammonium ions had a specifically favorable effect on the effectiveness of the remaining hydrogen ions for the hydrolysis of ethyl-n-hexanoate. From these findings, the important contributions of the hydrophobic forces, in addition to the electrostatic forces, is clearly demonstrated. 

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