Microwave-assisted catalytic pyrolysis of refuse-derived fuel (RDF) to improve pyrolysis performance and biochar properties

This paper investigated the feasibility of microwave-assisted catalytic pyrolysis (MACP) of refuse-derived fuel (RDF) to produce high quality biochar for the first time. Two main catalysts, K2CO3 and K3PO4, and their combination with bentonite or clinoptilolite were selected to mix with RDF in a fixed bed reactor exposed to microwave radiation. By comparing heating rate and biochar properties, the promising catalyst was identified as 20 wt% K2CO3 + 10 wt% bentonite due to its high heating rate (163 degrees C/min) and large specific surface area (264 m(2)/g) of biochar obtained under relatively low temperature (500 degrees C) and short microwave radiation time (30 min), much higher than previously reported values of RDF derived biochar (6-25 m(2)/g). K2CO3 showed higher heating rate and larger specific surface area of biochar than that of K3PO4 due to its prominent activation effect. Synergistic effect was observed when bentonite or clinoptilolite was added into K3PO4 which significantly improved microwave heating rate. Biochar produced from K2CO3 acts as a potential sorbent for retaining heavy metals in the biochar and soil due to its better porosity, while K3PO4 remaining in the biochar serves as essential nutrients for plant growth

Heck Alkynylation (Copper-Free Sonogashira Coupling) of Aryl and Heteroaryl Chlorides, Using Pd Complexes of <i>t</i>‑Bu₂(<i>p</i>‑NMe₂C₆H₄)P: Understanding the Structure–Activity Relationships and Copper Effects

L₂Pd­(0) and L₂Pd­(II) complexes, where L= <i>t</i>-Bu₂(<i>p</i>-NMe₂C₆H₄)­P, have been identified as efficient catalyst systems for the Heck alkynylation of a variety of aryl bromides (17 examples) and aryl/heteroaryl chlorides (31 examples) with a range of aryl- and alkyl-acetylenes in excellent yields, under relatively low Pd loadings. The single-crystal X-ray structure determination of the presumably active catalytic species, L₂Pd­(0), was carried out in this study to better understand the superior activity of the current catalyst system from a structure–activity relationship point of view. The P–Pd–P bond angle indicates that the complex is bent (174.7°) in comparison to the perfectly linear (180.0°) structure of the analogous Pd­(<i>t</i>-Bu₃P)₂. Preliminary mechanistic studies on the negative copper effect and substrate effect of aryl acetylenes were conducted to better understand the cross-coupling pathway of Heck alkynylation

Chiral Allene-Containing Phosphines in Asymmetric Catalysis

We demonstrate that allenes, chiral 1,2-dienes, appended with basic functionality can serve as ligands for transition metals. We describe an allene-containing bisphosphine that, when coordinated to Rh(I), promotes the asymmetric addition of arylboronic acids to α-keto esters with high enantioselectivity. Solution and solid-state structural analysis reveals that one olefin of the allene can coordinate to transition metals, generating bi- and tridentate ligands

Chiral Allene-Containing Phosphines in Asymmetric Catalysis

We demonstrate that allenes, chiral 1,2-dienes, appended with basic functionality can serve as ligands for transition metals. We describe an allene-containing bisphosphine that, when coordinated to Rh(I), promotes the asymmetric addition of arylboronic acids to α-keto esters with high enantioselectivity. Solution and solid-state structural analysis reveals that one olefin of the allene can coordinate to transition metals, generating bi- and tridentate ligands

Chiral Allene-Containing Phosphines in Asymmetric Catalysis

We demonstrate that allenes, chiral 1,2-dienes, appended with basic functionality can serve as ligands for transition metals. We describe an allene-containing bisphosphine that, when coordinated to Rh(I), promotes the asymmetric addition of arylboronic acids to α-keto esters with high enantioselectivity. Solution and solid-state structural analysis reveals that one olefin of the allene can coordinate to transition metals, generating bi- and tridentate ligands

Chiral Allene-Containing Phosphines in Asymmetric Catalysis

We demonstrate that allenes, chiral 1,2-dienes, appended with basic functionality can serve as ligands for transition metals. We describe an allene-containing bisphosphine that, when coordinated to Rh(I), promotes the asymmetric addition of arylboronic acids to α-keto esters with high enantioselectivity. Solution and solid-state structural analysis reveals that one olefin of the allene can coordinate to transition metals, generating bi- and tridentate ligands