3453-55-2Relevant articles and documents
Hierarchical ZSM-5 zeolite with uniform mesopores and improved catalytic properties
Serrano,Escola,Sanz,Garcia,Peral,Moreno,Linares
, p. 4206 - 4216 (2016)
Hierarchical ZSM-5 with uniform mesoporosity was synthesized by the sequential coupling of two strategies: generation of secondary porosity by the crystallization of silanized protozeolitic units and a subsequent treatment with a basic surfactant-containing solution. The ZSM-5 zeolite obtained exhibited high crystallinity and contained two levels of uniform porosities within the micro- and mesopore ranges, respectively. The uniform mesoporosity is the result of the reorganization of irregular mesopores, created initially from the silanized protozeolitic units, via the local rearrangement of zeolitic fragments, and promoted by contact with a cationic surfactant under mild basic conditions. Interestingly, this second treatment was less effective when it is applied to a non-hierarchical ZSM-5 sample, showing that the presence of initial secondary porosity is essential for allowing the surfactant/ammonia solution to modify the zeolite and form uniform mesopores. Characterization of the zeolite samples using different techniques showed that the crystallinity, Al coordination and acidic features of the zeolite do not change significantly after the mesopore narrowing treatment, even though significant variations in the textural properties are observed as expected. The effects of the occurrence of regular mesoporosity on the catalytic properties of the hierarchical ZSM-5 zeolite were proven using the acylation of 2-methoxynaphthalene as a test reaction. The material with uniform mesopores showed both the highest activity and selectivity towards 6-acetyl-2-methoxynaphthalene, which was interpreted as the result of the presence of a more regular and less rough mesopore surface, which in turn facilitated the interaction between the reactant molecules and the active sites located and distributed over the mesopores.
Acetylation of 2-methoxynaphtalene with acetic anhidryde over Zr4+-zeolite beta
Cahyono, Edy,Priatmoko, Sigit,Haryani, Sri
, p. 79 - 83 (2016/08/25)
Regioselective acetylation of 2-methoxy naphthalene (2-MN) to 2-acetyl-6-methoxy naphthalene (2,6-ACMN) is the important step in the synthesis of pharmaceutical compounds such as (S)-naproxen. The liquid phase acetylation of 2-MN with acetic anhydride over Zr4+-zeolite beta catalyst was investigated under controlled reaction conditions. Catalyst was prepared by ion exchange and impregnation method. Zr4+-zeolite beta(ie) was obtained by ion exchange that done with 0,5 M ZrCl4 then calcined at 550°C for 3 h and Zr4+-zeolite beta(ip) was obtained by impregnation method. Catalytic activity of catalysts was affected by preparing method, temperature, and reaction solvent. Catalyst that prepared by impregnation showed inactive on acetylation of 2-MN. 1-Acetyl-2-methoxynaphtalene (1,2-ACMN), 1-acetyl-7-methoxy-naphtalene (1,7-ACMN), and 2-acetyl-6-methoxy naphthalene (2,6-ACMN) were identified as the products of 2-MN acetylation over Zr4+-zeolite beta(ie) without solvent. Activity and selectivity of Zr4+-zeolite beta(ie) was increased in dichloromethane solvent at 140°C for 36 h, 1,8-ACMN was not identified and ratio of 1,2-ACMN to 2,6-ACMN was 1,6:1.
Acetylation of aromatic compounds over H-BEA zeolite: The influence of the substituents on the reactivity and on the catalyst stability
Guidotti, Matteo,Canaff, Christine,Coustard, Jean-Marie,Magnoux, Patrick,Guisnet, Michel
, p. 375 - 383 (2007/10/03)
The acylation with acetic anhydride of six aromatic substrates with different features (degree of activation of the aromatic ring towards electrophilic substitution, number of rings, i.e., 1 or 2) was carried out in a batch reactor at 373 K over a H-BEA zeolite (Si/Al = 15) with nitrobenzene as a solvent. The acetylation rate was found to be very dependent on the degree of ring activation, with diffusion limitations playing only a limited role. The decrease of the rate with reaction time, which was very pronounced with poorly activated and deactivated substrates, is mainly due to the inhibiting effect of acetic acid and of the products of acetic anhydride condensation.
