Synthesis of IM-5 Zeolite by Template Pre-Reaction

IM-5 zeolite was synthesized by hydrothermal crystallization method with 1,5-bis(N-methylpyrrolidinium)pentane bromide using the precursors N-methylpyrrolidine and 1,5-dibromopentane as raw materials of template after pre-reaction,and then aluminum,alkali,water and silicon sources were added into the reaction system.The effects of the proportion of precursors and other materials and the reaction conditions on the crystallinity,crystal morphology and pore structure of the synthesized zeolites were systematically investigated,which provided the basic data for industrial production.The physical properties of the synthesized samples were analyzed by XRD,SEM,and N2 adsorptiondesorption techniques,and the catalytic performance of the samples was evaluated.The results show that IM-5 zeolite can be synthesized effectively by using the template pre-reaction method,and its physical properties and catalytic activity in catalytic alkylation of benzene and methanol are comparable to those of industrial samples synthesized by traditional method.

Melting Properties of Loose and Granulated Glass Batch

The physical properties, the pre-reacting performance and melting properties of the loose glass batch and the granulated glass batch were investigated, respectively. The experimental results showed that compacted glass batch could reduce dust, use ultra-fine powder, and improve heat transfer efficiency. When loose glass batch was compressed into granular, the thermal conductivity was increased from 0.273 W/m·℃ to 0.430 W/m·℃, the activation energy Ea of pre-reacting decreased from 178.77 k J/mol to 143.30 k J/mol. Using the pre-reacted granular glass batch can significantly reduce the melting time, increase the batch melting rate, and decrease the heat consumption of 1kg molten glass from 3591.24 to 3277.03 kJ/kg.

Understanding the cooperative effects in the catalysis of homodimeric fluoroacetate dehalogenase

Fluoroacetate dehalogenases(FAcD),a homodimeric enzyme,catalyzes the conversion of fluoroacetic acid to glycolic acid(GoA).It has been proved that the enzyme has a half-of-the-site reactivity.Namely,its catalytic(C)subunit converts the first substrate to a covalent intermediate;then,the non-catalytic(NC)subunit binds a second substrate and promotes the conversion of the intermediate in the C subunit into the final product.After the release of the product,the C subunit becomes the NC subunit,and the previous NC subunit becomes the C subunit.To elucidate the detailed mechanism behind this cooperative catalysis,we have conducted microsecond-scale MD simulations along the reaction pathway.The simulations indicate that the substrate in the NC subunit induces W185 and Y141 adopting an open conformation in the C subunit.The opening of W185(C)facilitates the entry of catalytic water,enhancing the catalytic activity for product formation,while the opening of Y141(C)creates an unfavorable environment for product binding,promoting its release.An interaction network analysis reveals that the substrate in the NC subunit can induce conformational changes through a conserved water chain at the interface.