Boosting the in situ encapsulation of proteins with MIL-100(Fe): the role of strong Lewis acid centers

Encapsulation of biomolecules using Metal-Organic Frameworks (MOFs) to form stable biocomposites has been demonstrated a valuable strategy for their preservation and controlled release, which has been however restricted to specific electrostatic surface conditions. We present a general in situ strategy that promotes the spontaneous MOF growth onto a broad variety of proteins, for the first time, regardless of their surface nature. We demonstrate that MOFs based on cations exhibiting considerable inherent acidity such as MIL-100(Fe) enable biomolecule encapsulation, including alkaline proteins previously inaccesible by the welldeveloped in situ encapsulation with azolate-based MOFs. In particular, MIL-100(Fe) scaffold permits effective encapsulation of proteins with very distinct surface nature, retaining their activity and allowing triggered release under biocompatible conditions. This general strategy will enable an ample use of biomolecules in desired biolotechnological applications.

Liquid deposition modification of nano-ZSM-5 zeolite and catalytic performance in aromatization of Hexene-1

The Olefin aromatization is an important method for the upgrade of catalytic cracking (FCC) gasoline and production of fuel oil with high octane number. The nano-ZSM-5 zeolite was synthesized via a seed-induced method, a series of modified nano-ZSM-5 zeolite samples with different Ga deposition amount were prepared by Ga liquid deposition method. The XRD, N2 physical adsorption, SEM, TEM, XPS, H2-TPR and Py-IR measurements were used to characterize the morphology, textural properties and acidity of the modified ZSM-5 zeolites. The catalytic performance of the Hexene-1 aromatization was evaluated on a fixed-bed microreactor. The effects of Ga modification on the physicochemical and catalytic performance of nano-ZSM-5 zeolites were investigated. The Ga species in the modified nano-ZSM-5 zeolites mainly exist as the form of Ga2O3 and GaO+, which provide strong Lewis acid sites. The aromatics selectivity over Ga modified nano-ZSM-5 zeolite in the Hexene-1 aromatization was significantly increased, which could be attributed to the improvement of the dehydrogenation activity. The selectivity for aromatics over the Ga4.2/NZ5 catalyst with suitable Ga deposition amount reached 55.4%.

Effects of Framework Disruption of Ga and Ba Containing Zeolitic Materials by Thermal Treatment

The effect of the thermal treatment of some zeolitic materials was studied on oxidative dehydrogenation (ODH) of n-octane. Gallium containing faujasite catalysts were synthesized using isomorphic substitution, specifically, a galosilicalite (Ga-BaY(Sil)) and an aluminosilicalite substituted with gallium (Ga-BaY(IS)), with constant Si/M ratio. The catalysts were thermally treated at different temperatures (250, 550, and 750 °C) before catalytic testing. The quantification of total and strength of acid sites by FT-IR (O-H region), pyridine-IR, and NH3-temperature-programmed desorption (TPD) confirmed a decrease in the number of Brønsted acid sites and an increase in the number of Lewis acid sites upon increasing the calcination temperature. Isothermal n-octane conversion also decreased with the catalysts’ calcination temperature, whereas octene selectivity showed the opposite trend (also at iso-conversion). The COx selectivity showed a decrease over the catalysts calcined from 250 to 550 °C and then an increase over the 750 °C calcined catalysts, which was due to the strong adsorption of products to strong Lewis acid sites on the catalysts leading to the deep oxidation of the products. Only olefinic-cracked products were observed over the 750 °C calcined catalysts. This suggested that the thermal treatment increases Lewis acid sites, which activate n-octane using a bimolecular mechanism, instead of a monomolecular mechanism.

Highly-efficient Ru/Al–SBA-15 catalysts with strong Lewis acid sites for the water-assisted hydrogenation of p-phthalic acid

A Ru/Al–SBA-15 catalyst with excess Lewis acid sites displayed excellent efficiency (100%), high cis-isomer selectivity (84%), and exceptional stability towards hydrogenation of p-phthalic acid in water.

Al(ORF)3 (RF = C(CF3)3) activated silica: a well-defined weakly coordinating surface anion

A strong Lewis acid coordinates to silanols on silica to form a strong acid, which acts as a weakly coordinating anion when deprotonated.

Bonding between electron-deficient atoms: strong Lewis-acid character preserved in X–Y–X (X = B, Al; Y = Be, Mg) bridges

Beryllium bis(diazaborolyl) derivatives and their Mg and Al-containing analogues are stable compounds stabilized through covalent bonds between electron-deficient atoms, and behave as good Lewis acids.

A superstable 3p-block metal–organic framework platform towards prominent CO2 and C1/C2-hydrocarbon uptake and separation performance and strong Lewis acid catalysis for CO2 fixation

Superstable 3p-block MOF platforms exhibit excellent gas uptake and separation performance, and prominent Lewis acid catalysis for CO2 fixation.

Nb-doped variants of high surface aluminium fluoride: a very strong bi-acidic solid catalyst

Novel aluminium Nb-doped fluoride catalysts were synthesized using an aluminium hydroxide precursor to afford solids where very strong Lewis acid sites coexist with Brønsted acid sites.