Catalyst Amberlyst

Amberlyst catalysts are macroporous from Rohm and Haas Co... 

Tungstophosphoric acid (HPW) and its Cs and ammonium salts encapsulated into the channels of MCM-41 molecular sieves were useful for the conversion of phenol and acetone to Bisphenol-A. The Cs-HPW/MCM system was more selective to the p,p -isomer than that of zeolites ZSM-5 and H-Y. The Bisphenol-A is useful industrially in the production of polymeric resins. Various other catalysts such as Amberlyst resins were used for this purpose (equation 20). The latter catalyst gave a 90% selectivity for the p,p -isomer . The MCM-41 encapsulated catalyst was shown to have superior thermal characteristics compared to that of the Amberlyst catalyst. 

Amberlyst Catalysts (Rohm Haas) are among the most common resins used in etherification. They are strongly acidic macroreticular catalysts based on styrene divinilbenzene copolymers. In particular, the Amberlyst 35Wet gives the highest performances and lifetime and was specifically developed for MTBE, ETBE and TAME production. 

Lew, C.M., Rajabbeigi, N., Tsapatsis, M., 2012. One-pot synthesis of 5-(Ethoxymethyl) furfural from glucose using Sn-BEA and amberlyst catalysts. Industrial Engineering Chemistry Research 51, 5364—5366. 

The initial numerical data fitting for experimental data obtained with Smopex and Amberlyst catalysts revealed that good description can be achieved by setting a=l and estimating only four parameters (three rate constants feoi and P) dius improving the estimation statistics. The parameter errors were typically less than 8% and the degree of explanation was 99.8% and 99.5% for Smopex and Amberlyst, respectively. The parameter values and the estimation statistics are summarized in Table 11.6. 

A solution of trifluoroacetic acid in toluene was found to be advantageous for cydization of pyruvate hydrazoncs having nitro substituents[4]. p-Toluene-sulfonic acid or Amberlyst-15 in toluene has also been found to give excellent results in preparation of indole-2-carboxylale esters from pyruvate hydra-zoiies[5,6J. Acidic zeolite catalysts have been used with xylene as a solvent to convert phenylhydraziiies and ketones to indoles both in one-flask procedures and in a flow-through reactor[7]. 

Some work has also been achieved with heterogeneous catalysis. These catalysts include Amberlyst-15, Nafion-H, montmorillonite KSF clay, ferrihydrite silica gel aerogels containing 11-13% iron, silica sulfuric acid, and zeolites. ... 

A more effecdve catalyst for the Hetuy reacdon is a polymer-supported base such as amberlyst A-31. Various fi-nitro alcohols can be obtained v/ith the help of amberlyst v/ith or without solvent fEq, 3,14, A recent report claims that amberlite IRA-430 COH-formi or DOWEX-1 COH-formi is more effecdve for the Henry reacdon than amberlyst A-31/ Poly-... 

Equation (1) consists of various resistance terms. l/Kj a is the gas absorption resistance, while 1/ K,a corresponds to the maleic anhydride diffusion resistance and l/i k represents the chemical reaction resistance. The reaction rate data obtained under the reaction conditions of 250°C and 70 atm were plotted according to equation (1). Although catalytic reaction data with respect to time on stream were not shown here, a linear correlation between reaction rate data and catalyst loading was observed as shown in Fig. 2. The gas absorption resistance (1/ a) was -1.26 h, while the combined reaction-diffusion resistance (lJK,a + 1 T]k) was determined to be 5.57 h. The small negative value of gas absorption resistance indicates that the gas-liquid diffusion resistance was very small and had several orders of magnitude less than the chanical reaction resistance, as similarly observed for the isobutene hydration over Amberlyst-15 in a slurry reactor [6]. This indicates that absorption of malei c anhydride in solvent was a rapid process compared to the reaction rate on the catalyst surface. 

Percent isotopic composition ( 2 mol%) of O-containing products formed over the Amberlyst-35 catalyst (03 g) from the reaction of 0-methanol (or 0-ethanol) with 0-isobutanol at 110°C, 1 MPa, and GHSV = 14300 /kg catal/hr. 

The availability of Nafion on silica has not only lowered the cost of the resin but also has made it versatile (Sun et al., 1997 Harmer et al., 1998). A number of industrially important reactions have been attempted, with considerable success, with these catalysts. Consider the Fries rearrangement of phenyl acetate to p-acetyl phenol (/t-hydroxy acetophenone). This has been accomplished by Hoelderich and co-workers (Heidekum, 1998). In the ca.se of alkylation of benzene with benzyl alcohol, Amberlyst-15 and p-toluene sulphonic acid are ineffective and Nafion on silica works well at 80 °C. 

The selectivity for cross-dimerization relative to the dimerization of AMS, was found to be better with the acid-treated clay catalyst Engelhard F-24 than with the ion-exchange resin catalyst Amberlyst-15. Also, the formation of undesired side products, i.e. diisoamylenes, was lower in the case of Engelhard F-24 than for Amberlyst-15. 

Scott Oakes et al. (1999a, b) have shown how adoption of SC conditions can lead to a dramatic pressure-dependent enhancement of diastereoselectivity. In the case of sulphoxidation of cysteine derivatives with rert-butyl hydroperoxide, with cationic ion-exchange resin Amberlyst-15 as a catalyst, 95% de was realized at 40 °C and with SC CO2. By contrast, with conventional solvents no distereoselectivity was observed. Another example is the Diels-Alder reaction of acrylates with cyclopentadiene in SC CO2 at 50 °C, with scandium tris (trifluoromethanesulphonate) as a Lewis acid catalyst. The endoiexo ratio of the product was as high as 24 1, while in a solvent like toluene it was only 10 1. 

Very recently, Nolan et al. studied several acidic polymeric catalysts for the esterification of fatty acids. The highest FFA conversion (45.7%) was obtained over strong acidic macroreticular polymer catalysts AmberlysH 15 at 60°C compared with Amberlyst 35, Amberlyst 16, and Dowex HCR-W2. 

Amberlyst BD20 is a patent-pending catalyst mannfactured by Rohm and Haas Company. Its key properties are listed in Table 32.1. Figure 32.1 below shows a micrograph of the actual catalyst. 

A fixed-bed reactor system was employed (Figure 32.2). Each of the two reactors was charged with 38 cc of Amberlyst BD20 catalyst. Sample ports located at the exit of each reactor enabled increased acquisition of residence time data. Pressure was maintained by a back pressure control valve to maintain methanol in the liquid phase. After charging, the 1st and then 2nd reactors were connected to the pumps and filled with the reaction mixture while vapor was released from each through the top vent valve. Once each reactor was filled with liquid and emptied of vapor, the pressure regulator was connected to the output and both reactors were immersed into the water bath. 

LHSV = Total Liquid Flow Rate (cc/hr) / Total Amberlyst BD20 Catalyst Volume (cc)... 

Yuen et al. [24] first demonstrated the nature of the information that can be obtained regarding chemical mapping within a fixed-bed reactor, using the liquid phase esterification of methanol and acetic acid catalyzed within a fixed bed of H+ ion-exchange resin (Amberlyst 15, particle size 600-850-pm) catalyst as the model... 

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... 

A more effective catalyst for the Henry reaction is a polymer-supported base such as amberlyst A-21. Various P-nitro alcohols can he obtained with the help of amberlyst with or without solvent (Eq. 3.14).25 A recent report claims that amberlite IRA-420 (OH-form) or DOWEX-1 (OH-form) is more effective for the Henry reaction than amberlyst A-21.26 Poly-... 

Selectivity to ethers over H-BEA-25 and H-FAU-30 are always higher than 90 % at 160 - 200°C, similarly as in case of thermally stable resin Amberlyst 70, but zeolites are far less active [5,10], Activation energies for investigated catalysts computed from initial reaction rates (Table 3) are comparable to those for Amberlyst 70 (119 + 4 kJ/mol for DNHE synthesis [10], and 115 + 5 kJ/mol for DNPE synthesis [5], respectively)... 

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. 

Cation-exchange resins are used as catalysts in the produdion of MTBE (methyl tertiary-butyl ether, 2-methoxy-2-methylpropane) and various other oxygenates and, lately, also in the dimerization of isobutene [30]. Other commercial applications of the cation-exchange resins indude dehydration of alcohols, alkylation of phenols, condensation readions, alkene hydration, purification of phenol, ester hydrolysis and other reactions [31]. The major producers of ion-exchange resins are Sybron Chemicals Incorporated [32] (Lewatit resins), Dow Chemical Company [33] (DOWEX resins), Purolite [28] (Purolite resins), and Rohm and Haas Company [27] (Amberlyst resins). 

Klepacova et al. [23] have tested several commerdal strongly acidic ion-exchange resins with a madoreticular structure (Amberlyst A15, A35, A36 and A39) and with a gel strudure (Amberlyst A31 and A119) and two commerdal large-pore zeolites (H-Y and H-Beta). Ion exchange resin catalysts A15 and A35 with a highly crosslinked strudure were very adive in the dry and also in the wet form [23]. 

TBA and isobutene have been compared as the etherifying agent at 60 °C. The initial molar ratio of isobutene to glycerol was 4.0 with Amberlyst A35 as the catalyst. The conversion of glycerol is lower when etherified with TBA than when etherified with isobutene. More hydrocarbons are formed with isobutene than with TBA. But, with TBA, mainly monoethers are formed and valuable triethers are formed only in small amounts. In addition, TBA dehydrates to water, which has an inhibition effect on ion-exchange resin catalysts [23],... 

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