Montmorillonite catalyst

Keywords clay catalyze(i reactions, montmorillonite catalyst, kaolinite catalyst... 

Zinc chloride exchanged clay catalysts have been reported to be highly active for the Friedel-Crafts alkylation and acylation reactions these are commercially sold by Contract Catalysts under the name Envirocats. These are montmorillonite catalysts modified by ZnCU and FeCli. Some of the reported examples of Friedel-Crafts reactions are given below there are claims that some of the processes are commercially practised. 

When organic cations (e.g., cationic tensides) are employed, clay organo-complexes are formed, which can be used in organic solvents. A Pd-hexadecy-lammonium montmorillonite catalyst was prepared by the reduction of Pd(OAc)2 by ethanol in the interlamellar space. At small ethanol concentrations in toluene, selective interlamellar sorption of ethanol was established consequently, the reduction also occurred only in the interlamellar space.160 The catalyst was used for the hydrogenation of alkenes.161... 

The original epoxidation with titanium-tartrate is homogeneous, but it can be carried out heterogeneously without diminishing enantioselectivity by using titanium-pillared montmorillonite catalyst (Ti-PILC) prepared from titanium isopropoxide, (+)-DAT, and Na+-montmorillonite.38 Due to the limited spacing of Ti-PILC, the epoxidation becomes slower as the allylic alcohol gets bulkier. 

K. Motokura, N. Nakagiri, T. Mizugaki, K. Ebitani, and K. Kaneda, Nucleophilic substitution reactions of alcohols with use of montmorillonite catalysts as solid Br0nsted acids, J. Org. Chem., 72 (2007) 6006-6015. 

It was found that in the catalytic transformation of 2- and 4-t-butylphenol in the liquid phase on heterogeneous KSF and K10 montmorillonite catalysts under micro-wave and conventional conditions the microwaves affected both the rate and the selectivity of the reaction. 

The low H/C-ratio of FCC feed derived from liquefied biomass led to low conversion and poor gasoline selectivity. Addition of alumina to the matrix resulted in a catalyst more active for heavy oil cracking but with a poor selectivity. Alumina-montmorillonite catalysts showed activities for heavy oil cracking comparable to that of a conventional, zeolite based, cracking catalyst. Effects of matrix composition and zeolite type on the heavy oil cracking performance are discussed. 

SCHEME 119. Selective oxidation of alcohols using a chromium-pillared montmorillonite catalyst and TBHP... 

Raffinate Hydrocracking with Palladium-Nickel— Containing Synthetic Mica-Montmorillonite Catalysts... 

The reaction time has been reduced dramatically by the addition of calcium hydride, silica gel, or montmorillonite catalysts.30,39"11... 

Adams, J. M. 1987. Synthetic organic chemistry using pillared, cation-exchanged and acid-treated montmorillonite catalysts a review. Appl. Clay Sci, 2 309-342. 

Basic nitrogen compounds form in FTT reactions in the presence of NHj (Fig. 6). In the early experiments, the temperature was briefly raised to 500-700 °C (Hayatsu et al., 1968, 1972 Yang and Oro, 1971), but this may not be necessary, at least with a montmorillonite catalyst (Anders et al., 1974). The reaction mechanism is obscure, but probably involves reactive intermediates such as HCN, nitriles, or acetylenes (Hayatsu et al., 1968, 1972 Anders et al., 1974). It is not clear whether a liquid water phase, as generally formed in the cold neck of the vessel, is e ntial. A detail, systematic study of this reaction would be very desirable, to see what conditions are required, and whether they are realistic for the solar nebula. 

With a vermiculite catalyst, the alkylation of benzene with p-methyl benzyl chloride (1) at 80°C gave the mono-alkylated product, 2, in greater than 90% yield. No dialkylated product was formed (Eqn. 22.1). With a montmorillonite catalyst the reaction proceeded to give a 50% yield of this product and then stopped. ... 

The vapor phase N-alkylation of aniline with ethanol took place over an H-ZSM-5 catalyst at temperatures between 250° and 500°C. The maximum selectivity for N-monoethylation occurred at the lower temperatures with increasing amounts of diethyl aniline produced at higher reaction temperatures. v/ith montmorillonite catalyst, reaction at 400°C gave a 64% selectivity for N-ethyl aniline formation at 77% conversion. A vanadium exchanged montmorillonite was more active but less selective giving N-ethyl aniline in 48% selectivity and N, N-diethyl aniline in 37% selectivity at 97% conversion.94... 

A successful example for this class of reaction was reported by Choudary et al. [53a]. With the combination of a dialkyl tartrate and titanium-pillared montmorillonite (Ti-PILC), excellent ee-values in the range of90-98% were achieved (Scheme 2.19). In contrast to the homogeneous conditions, this heterogeneous system was operational without the use of molecular sieves however, no recychng experiment was reported. Distinct from Ti-PILC, the use of vanadium-piUared montmorillonite catalyst for the AE of ( )-hex-2-enol, however, led to only 20% enantiomeric excess [53b]. 

Similarly, chromia-pillared montmorillonite catalyst reportedly [39] catalyzes the selective oxidation of alcohols with TBHP and titanium-montmorillonite in conjunction with tartaric acid esters functions as a heterogeneous catalyst for asymmetric epoxidations with TBHP [40]. 

A 100 ml thermostated Parr autoclave was charged with the reactant (5ml), rhodium montmorillonite catalyst (100 mg) and with 200 psi of hydrogen at room temperature. The autoclave was purged with hydrogen before charging at room temperature. The autoclave was then heated at 100°C for 20 hours. The reaction mixture was then cooled, separated from the catalyst and analysed by GC. GC analysis was carried out on a Hewlett Packard model 5890 gas chromatograph using FID and HP-101 column. 

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