A novel strategy for stabilization of sub-nanometric Pd colloids on kryptofix functionalized MCM-41: nanoengineered material for Stille coupling transformation

The stabilization of sub-nanometric metal particles (< 1 nm) with suitable distribution remained challenging in the catalytic arena. Herein, an intelligent strategy was described to anchoring and stabilizing sub-nanometric Pd colloids with an average size of 0.88 nm onto Kryptofix 23 functionalized MCM-41. Then, the catalytic activity of Pd@Kryf/MCM-41 was developed in Stille coupling reaction with a turnover frequency (TOF) value of 247 h−1. The findings demonstrate that porous MCM-41 structure and high-affinity Kryptofix 23 ligand toward adsorption of Pd colloids has a vital role in stabilizing the sub-nanometric particles and subsequent catalytic activity. Overall, these results suggest that Pd@Kryf/MCM-41 is a greener, more suitable option for large-scale applications and provides new insights into the stabilization of sub-nanometric metal particles.

Catalytic Performance of Phosphorus Incorporated HZSM-5 in Coupling Transformation of Methanol with 1-butene to Propylene

Directly incorporated phosphorus species into the framework of HZSM-5 zeolite (H[P, Al]-ZSM-5) was successfully synthesized by the facile hydrothermal method. It was characterized by employing XRD, ICP-OES, SEM, FT-IR, N2 adsorption-desorption, NH3-TPD, XPS and TG-DTA, respectively. The effects of the phosphorus species content, temperature, WHSV, and the molar ratio of methanol/1-butene in coupling transformation of methanol with 1-butene to propylene catalyzed by H[P, Al]-ZSM-5 in a fixed bed reactor were studied systematically. Tests have suggested the acid content and specific surface area of H[P, Al]-ZSM-5 are reduced. Under the condition of reaction temperature at 550�Z, molar ratio of methanol/1-butene to 1.0, reaction pressure at 0.1 MPa and WHSV= 3.53 h-1, the P-modified HZSM-5 zeolite (with the P2O5 molar composition of 0.4 )the selectivity and yield of propylene are 35.6% and 32.5%, respectively.

Phosphorus Promoted HZSM-5 Zeolites for the Coupling Transformation of Methanol with 1-Butene to Propylene

Phosphorus promoted HZSM-5 zeolites (P-HZSM-5) were prepared by synthetic methods of incipient wetness impregnation and in-situ synthesis, respectively. It was characterized by the means of XRD, SEM, BET, TG and NH3-TPD. The P-HZSM-5 zeolite prepared by incipient wetness impregnation has a large specific surface area and pore size, and the weak acidity is remarkably increased. The catalytic activity of P-HZSM-5 for the coupling transformation of methanol with 1-butene to propylene was investigated. Under the reaction conditions of temperature at 550 ℃, pressure at 0.4 MPa, space velocity at 1800 mL/(gcath) and mole ratio of CH3OH/C4H8 to 1:1, the conversion of C4H8 can reach to 75.8%, and the selectivity and yield of propylene are 42.2% and 31.9%, respectively.

Research on key technology and application of flexibility transformation of heating unit to improve clean energy consumption capacity

The electric regulation capacity of heating units has been constantly improving due to the promotion of the heating units? flexibility transformation. This improvement has effectively alleviated the long remained serious wind and light abandonment phenomena in the heating season in China. In this paper, we discussed the key technologies of the LP zero output heating mode and bypass heating mode, both of which are widely used in thermo-electric decoupling. Moreover, the coupling transformation of the two heating modes has been successfully realized in a heating unit. The electric regulation capacity of the unit has been greatly improved, from 18.6% before the transformation to 66.7%, and the minimum technical output has been also reduced to 14.2% THA. After the transformation, the unit now is able to provide several heating modes with its operational flexibility greatly improved. By comparing the economical efficiency of these heating modes, we obtained the operation mode with the lowest heat rate. This transformation mode provides a huge grid space for the consumption of clean energy, so it is of positive reference value and exemplary significance in implementing the flexibility transformation of heating units.

Alternative pathways to α,β-unsaturated ketones via direct oxidative coupling transformation using Sr-doped LaCoO 3 perovskite catalyst

A strontium-doped lanthanum cobaltite perovskite material was prepared, and used as a recyclable and effective heterogeneous catalyst for the direct oxidative coupling of alkenes with aromatic aldehydes to produce α,β-unsaturated ketones. The reaction afforded high yields in the presence of di- tert -butylperoxide as oxidant. Single oxides or salts of strontium, lanthanum and cobalt, and the undoped perovskite offered a lower catalytic activity than the strontium-doped perovskite. Benzaldehyde could be replaced by benzyl alcohol, dibenzyl ether, 2-oxo-2-phenylacetaldehyde, 2-bromoacetophenone or (dimethoxymethyl) benzene in the oxidative coupling reaction with alkenes. To our best knowledge, reactions between these starting materials with alkenes are new and unknown in the literature.

Locating ‘Deliberativeness’

Chapter six takes the systems account from chapter five and develops its empirical implications. It begins by setting out again the definition of the deliberative quality before returning to the additive and summative distinction set out in the introduction, testing how far one can push the summative idea before it, settling on a weak rather than strong account that insists on a role for citizen deliberation. It then develops the empirical cues of the resulting account through a series of linked questions about the nature of agency and inclusion; venues; memes and storylines; transmission and coupling; transformation and deliberative education; and decision-making and implementation. It argues that faithful transmission is often an unreasonable goal, depending on the context of power relations; but that the tensions can be managed by representation relationships and, thinking laterally, education that trains people to operate in multiple contexts.

Sulfur reduction coupled with anaerobic ammonium oxidation drove prebiotic proto-anabolic networks

SUMMARYThe geochemical energy that drove the transition from geochemistry to biochemistry on early Earth remains unknown. Here, we show that the reduction of sulfurous species, such as thiosulfate, sulfite, elemental sulfur, and sulfate, coupled with anaerobic ammonium oxidation (Sammox), could have provided the primordial redox equivalents and proton potential for prebiotic proto-anabolic networks consisting of the reductive acetyl-CoA pathway combined with the incomplete reductive tricarboxylic acid (rTCA) cycle under mild hydrothermal conditions. Sammox-driven prebiotic proto-anabolic networks (SPPN) include CO2 reduction, esterification, reductive amination, pyrrole synthesis, and peptides synthesis, in one geochemical setting. Iron-sulfur (FeS) minerals, as the proto-catalysts, enhanced the efficiency of SPPN. Thiols/thioesters were used as the energy currency in non-enzymatic phosphate-independent metabolism and accelerated SPPN. Peptides that consisted of 15 proteinogenic amino acids were the end products of SPPN with bicarbonate as the only source of carbon. Most peptides shared high similarity with the truly minimal protein content (TMPC) of the last universal common ancestor (LUCA). The peptides and/or proteinogenic amino acids might have endowed SPPN with autocatalysis and homochirality. Thus, Sammox drove the coupling transformation of carbon, hydrogen, oxygen, nitrogen, sulfur, and/or iron simultaneously in the far-from-equilibrium environment, thereby initiating the emergence of biochemistry. The existing Sammox microorganisms might belong to the phylum of Planctomycetes, and might be transitional forms between the three domains of life.