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PROCESSO CONTINUO DI CONVERSIONE CATALITICA,IN FASE GASSOSA,DI ALCOLI IN CLORURI E BROMURI ALCHILICI CON ACIDO CLORIDRICO (BROMIDRICO) ACQUOSO
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Synthesis, catalytic activity, and behavior of phase-transfer catalysts supported on silica gel. Strong influence of substrate adsorption on the polar polymeric matrix on the efficiency of the immobilized phosphonium salts
No full textCatalysis Mechanism of Phosphonium Salts Supported on Silica Gel in Aqueous-Organic Two-Phase System
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"Phase-Transfer Catalysts Immobilized and Adsorbed on Alumina and Silica Gel
No full textOnium salts immobilized on alumina have been shown to be effective phase-transfer catalysts in comparison to analogous soluble catalysts adsorbed on silica or alumina. Appreciable selectivity has been observed in the nucleophilic substitution reaction with aqueous potassium iodide toward halide of different sizes (1-bromobutane, 1-bromooctane, and 1-bromohexadecane). Alumina and silica gel immobilized onium salts can also act very effectively as reagents when used in stoichiometric quantities. © 1982, American Chemical Society. All rights reserved
Very Polar Onium Salts Immobilized on a Very Polar Matrix; Process for their preparation
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Continuous alkylation of cpds. contg. active methylene gps.
No full textAlkylation with (B) alkyl halides, -mesylates and -tosylates, takes place by passing a gaseous mixt. of cpd. (A) contg. acid CH gp. and (B) through a catalyst bed of alkali carbonate or bicarbonate supporting an adsorbed phase transfer catalyst. The process pref. takes place at 150-200 (170-180) deg. C under pressure ((10-30) x 10 power 5)/760 esp. (20 x 10 power 5)/ 760 Pa. The reaction prods. are recovered by condensation at the outlet of the column contg. the catalyst bed. (A) is esp. a malonate diester, an acetoacetate ester or acetyl acetone. The phase transfer catalyst can be tetrabutyl phosphonium bromide, a polyethylene glycol, esp. Carbowax 6000, or a crown ether, esp. 18-crown-6- or dibenzo-18-crown-6. K2CO3 or NaHCO3 is used as base and catalyst-carrier. Molar ratio base: (A) is 2.5 : 1. Molar ratio (B) : (A) is 1.5-1.; The throughput of reactants through column can be 1-5 ml/hr. vol. of column. The process is carried out without solvents and without stirring. Pure prods. are obtd. at a high reaction rate
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