Amberlite catalyst

In this synthesis, the cationic resin Amberlite IR 122 was used as catalyst. The product was isolated by high vacuum distillation at 175°, a temperature which may have also depolymerized some of the open-chained oligomers present. ... 

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-... 

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]. 

Resting cell of G. candidum, as well as dried cell, has been shown to be an effective catalyst for the asymmetric reduction. Both enantiomers of secondary alcohols were prepared by reduction of the corresponding ketones with a single microbe [23]. Reduction of aromatic ketones with G. candidum IFO 5 767 afforded the corresponding (S)-alcohols in an excellent enantioselectivity when amberlite XAD-7, a hydro-phobic polymer, was added to the reaction system, and the reduction with the same microbe afforded (R)-alcohols, also in an excellent enantioselectivity, when the reaction was conducted under aerobic conditions (Figure 8.31). 

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-... 

The high catalyst loading typical of sol gel entrapped catalysts ensures a desirably high substrate/catalyst (S/C) ratio as the major part of the heterogeneous catalyst weight originates from the silicate matrix. For example, in a preparative-scale reaction of the alcohol raol-(2-naphthyl)-ethanol only 250 mg of sol-gel CaLB immobilizate could be used per 10 g of substrate. For comparison, all this makes the process based on sol-gel immobilized lipase very competitive with the commercial BASF process using lipase immobilized on Amberlite to produce the amine at a scale of 1000 tons per year. 

The catalyst obtained via anion exchange with the commercial resin Amberlite lRA-900 showed excellent selectivity in epoxidation of acid-sensitive natural terpenes and allylic alcohols [73-75]. The selectivity of 92% at 83% conversion was attained in epoxidation of a-pinene and limonene. The catalytic activity of the reused catalyst was completely maintained after several catalytic cycles, and the filtrate was catalytically inactive [75]. 

These PVP polymers provide a "proximal effect" without addition of free pyridine in the reaction mixture. Different studies have shown that only one pyridine per manganese catalyst is sufficient to enhance the rate of the catalytic oxygen atom transfer from the high-valent metal-oxo species to the organic substrate. The advantage of PVP polymer over a cationic Amberlite resin (see Scheme II for structures) have been recently illustrated in the modeling of ligninase (11). 

Fig. 19- The efficiency, q, of the Amberlite IR-120 ion exchanger catalyst in ester hydrolysis as a function of the entropy, S, of the parent hydrocarbon RH or R H of the substituents, (a) Hydrolysis (at 25—45°C) of methyl esters RCOOCH3 [366] 1, acetate 2, chloroacetate 3, benzoate 4, cyclopentanecarboxylate 5, phenylacetate 6, a-naphthylacetate 7, 1-octanoate. (b) Hydrolysis (at 35°C) of acetates CH3COOR [480] 1, methyl 2, ethyl 3, cyclopentyl 4, cyclohexyl 5, 1-butyl 6, 2-pentyl 7, 1 -pentyl 8, 1 -hexyl 9, 1 -octyl,...

Effect of ester structure on the efficiency of ion exchanger in water [476] (Catalyst Amberlite IR-100 temperature 25°C.)... 

The silicic acid used for column chromatography and the Amberlite resin were Silicar CC-7 100-200 mesh purchased from Mallinckrodt Chemical Works, St. Louis, Mo. The 5% palladium on charcoal catalyst was purchased from Engelhard Industries Ltd., Newark, N. J. The tri-O-acetyl-D-glucal and the tri-O-acetyl-D-galactal (as a 70% solution in benzene) were purchased from Raylo Chemicals Limited, Edmonton, Alberta. 

The esterification of -butyl alcohol and oleic acid with a phenol—formaldehydesulfonic acid resin (similar to amberlite IR-100) is essentially second order after an initial slow period (52). The velocity constant is direcdy proportional to the surface area of the catalyst per unit weight of reactants. 

The conventional resinsulfonic acids such as sulfonated polystyrenes (Dowex-50, Amberlite IR-112, and Permutit Q) are of moderate acidity with limited thermal stability. Therefore, they can be used only to catalyze alkylation of relatively reactive aromatic compounds (like phenol) with alkenes, alcohols, and alkyl halides. Nafion-H, however, has been found to be a suitable superacid catalyst in the 110-190°C temperature range to alkylate benzene with ethylene (vide infra) 16 Furthermore, various solid acid catalysts (ZSM-5, zeolite /3, MCM-22) are applied in industrial ethylbenzene technologies in the vapor phase.177... 

Anion exchange resins of the quaternary ammonium hydroxide type [e.g. Zerolit FF or Amberlite (IRA-400)] are strong bases and are useful catalysts for cyanoethylation of alcohols. No additional basic catalyst is normally required in the case of the cyanoethylation of aliphatic amines. 

Zs-3-Phenylpropenoic acid (0.025 g, 0.16 mmol), Amberlite IRA 938-supported formate (0.2 g) and Wilkinson s catalyst (0.04 g, 0.0043 mmol) were suspended in dimethylsulfoxide (0.5 ml) in a reaction tube. The mixture was irradiated with microwaves at 100 W for 30 s. On cooling, the mixture was diluted with dichloromethane (5 ml) and filtered. The filtrate was washed with water (2x5 ml). The organic layer was dried over anhydrous magnesium sulfate, the solvent removed under reduced pressure, and the residue was purified by filtration through a plug of alumina to give 3-phenylpropanoic acid (0.024 g, 95% yield). 

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