Effect of a Swelling Agent on the Performance of Ni/Porous Silica Catalyst for CH4-CO2 Reforming.

Hierarchical porous materials are of great interest in various industrial applications because of their potential to overcome the mass transport limitations typically encountered for single-mode porous materials. This report describes the synthesis of a hierarchical trimodal porous silica-based material using a 7.5 molar ratio of a relatively inexpensive nonionic surfactant template, triblock copolymer P123, EO20PO70EO20. The pore size distribution curve shows the presence of three types of pores with average diameters of ∼8, 25, and 89 nm. Electron microscope images confirm the existence of smaller ordered mesopores (first mode), larger ordered mesopores (second mode), and macropores (third mode). Ni nanoparticles dispersed on this trimodal porous silica produce a material that exhibited excellent catalytic performance for the CO2 reforming of CH4. This research provides new insights that will facilitate the development of trimodal porous silica (TMS) materials for a variety of applications. The results demonstrated that the presence of large pores (second and third mode pores) in TMS material increased the number of accessible active Ni sites, which led to the high activity observed for Ni/TMS catalyst.

Techno-Economic Analysis for Direct Processing of Wet Solid Residues Originated from Grain and Inedible Plant Wastes.

Large number of solid wastes is produced from ethanol and wine plants sourcing from grain and inedible plant wastes, for example, WDGS (wet distiller's grain with soluble) and DDGS (dry distiller's grain with soluble) produced from ethanol plants using corn. This study investigates alternative methods for using these co-products through combustion and anaerobic digestion. Process simulation and economic analysis were conducted using current market prices to evaluate the viability of the processes. Products in the form of energy are produced. Optimization of the corn ethanol plant was also explored for re-using the heat and electricity produced in those processes. These processes will supply more viable options to utilisation of those wastes. The anaerobic digestion of WDGS to produce electricity scenario was found to have the biggest profit among the four scenarios which can bring the annual income of 14.1 million Australian dollar to the ethanol plant. An environmental analysis of the CO2 emissions was also conducted. Using the Australian state emission factor, the amount of CO2 offset through both combustion and anaerobic digestion can be seen. The anaerobic digestion of WDGS to supply heat to the plant was proved having the largest CO2 abatement with the value of 0.58 kg-CO2e/L-EtOH. Supplementary Information: The online version contains supplementary material available at 10.1007/s12155-022-10501-6.

Aerosol generation related to respiratory interventions and the effectiveness of a personal ventilation hood.

OBJECTIVE: To quantify aerosol generation from respiratory interventions and the effectiveness of their removal by a personal ventilation hood. DESIGN AND SETTING: Determination of the aerosol particle generation (in a single, healthy volunteer in a clean room) associated with breathing, speaking, wet coughing, oxygen (O2) 15 L/min via face mask, O2 60 L/min via nasal prongs, bilevel non-invasive positive-pressure ventilation (BiPAP) and nebulisation with O2 10 L/min. INTERVENTIONS: Aerosol generation was measured with two particle sizer and counter devices, focusing on aerosols 0.5-5 µm (human-generated aerosols), with and without the hood. An increase from baseline of less than 0.3 particles per mL was considered a low level of generation. MAIN OUTCOME MEASURES: Comparisons of aerosol generation between different respiratory interventions. Effectiveness of aerosol reduction by a personal ventilation hood. RESULTS: Results for the 0.5-5 µm aerosol range. Quiet breathing and talking demonstrated very low increase in aerosols (< 0.1 particles/mL). Aerosol generation was low for wet coughing (0.1 particles/mL), O2 15 L/min via face mask (0.18 particles/mL), and high flow nasal O2 60 L/min (0.24 particles/mL). Non-invasive ventilation generated moderate aerosols (29.7 particles/mL) and nebulisation very high aerosols (1086 particles/mL); the personal ventilation hood reduced the aerosol counts by 98% to 0.5 particles/mL and 8.9 particles/mL respectively. CONCLUSIONS: In this human volunteer study, the administration of O2 15 L/min by face mask and 60 L/min nasal therapy did not increase aerosol generation beyond low levels. Non-invasive ventilation caused moderate aerosol generation and nebulisation therapy very high aerosol generation. The personal ventilation hood reduced the aerosol counts by at least 98%.

Sustainable options for the utilization of solid residues from wine production.

The efficient use of solid organic waste materials is an issue of particular importance for the wine industry. This paper focuses on the valorization of grape marc, the major component of winery organic waste (60-70%). Two methods were designed and compared: combustion to generate electricity, and the pyrolysis for the production of bio-char, bio-oil, and bio-gas. Each of these processes was analysed to determine their economic and environmental viability. The flow-sheeting software, ASPEN PLUS, was used to model the two cases. Data from the simulations was used to inform techno-economic and environmental analyses. Pyrolysis was found to be the superior method of utilizing grape marc from both economic and environmental perspectives. Both pyrolysis and combustion exploit the energy content of the waste, which is not recovered by the traditional treatments, composting or distillation. In addition to the production of energy, pyrolysis yielded 151kg of bio-char and 140kg of bio-oil per tonne of grape marc. These products may be used in place of fossil fuels, resulting in a net reduction of carbon dioxide emissions. However, the potential deleterious effects resulting from the replacement of the traditional treatments was not considered. Investment in either pyrolysis or combustion had a negligible impact on the price of the wine produced for wineries with an annual grape crush larger than 1000 tonnes. Composting has significant economic advantages in wineries with a small grape crush of less than 50 tonnes.

Cobalt-bis(imino)pyridine complexes as catalysts for hydroalumination-isomerisation of internal olefins.

The insertion of α- and internal octenes (hydroalumination) and chain walking isomerisation at di-n-octylaluminium hydride [Al(Oct)2H], catalysed by bis(imino)pyridine-Co complexes has been investigated by NMR spectroscopy. The Co-based catalysts promote efficient hydroalumination of 1-octene. Internal olefins are partially hydroaluminated, with isomerisation to the primary alkyls, but the catalyst responsible appears to deactivate rapidly. The reaction between the Co precatalysts and [Al(Oct)2H] generates a Co-hydride species, likely to be a hydride bridged dinuclear Co and Al complex. This species is reactive towards α-olefins but inert towards internal olefins. In contrast to hydroalumination, the catalysts promote efficient hydroboration, where insertion and isomerisation of internal octenes goes to completion. The differences between the systems may be partially ascribed to formation of an active mononuclear Co catalyst in the borane system versus a less active Co/Al dinuclear complex in hydroalumination.

A one pot, metathesis-hydrogenation sequence for the selective formation of carbon-carbon bonds.

A combination of homogeneous hydrogenation and metathesis reactions allows highly efficient, stepwise chemo- and stereoselective formation of three separate 2,7-diaminosuberic acid derivatives in a single pot without isolation of intermediates.

Cross-metathesis of unsaturated natural oils with 2-butene. High conversion and productive catalyst turnovers.

The cross-metathesis of synthetic and natural triglycerides containing unsaturated fatty acids with 2-butene can be achieved with high conversion and excellent productive turnovers. These reactions are catalysed by second-generation ruthenium-based olefin metathesis catalysts and can be conducted at -5 degrees C in liquid 2-butene.

Insertion and isomerisation of internal olefins at alkylaluminium hydride: catalysis with zirconocene dichloride.

The insertion of internal olefins (hydroalumination) and chain walking isomerisation at di-n-octylaluminium hydride [Al(Oct)2H], promoted by zirconocene dichloride [Cp2ZrCl2] has been studied. The reaction between [Cp2ZrCl2] and [Al(Oct)2H] in non-polar solvents leads to clusters containing bridging hydride ligands between Zr and Al. This system promotes hydroalumination of 1-octene but is largely ineffective for internal octenes (2-, 3-, 4-octene). In tetrahydrofuran the Zr-Al hydride clusters formed are more reactive and catalyse insertion and isomerisation of internal olefins to primary metal-alkyls, although this is accompanied by catalyst deactivation. Elimination and removal of 1-octene from the system post insertion/isomerisation was attempted, but it was found that the presence of the Zr catalyst leads to back-isomerisation to internal octenes, along with further decomposition with n-octane formation. Some possible pathways of catalyst decomposition, involving reduction of Zr and alkane elimination, have been studied theoretically.

Insertion, elimination and isomerisation of olefins at alkylaluminium hydride: an experimental and theoretical study.

The insertion, elimination and isomerisation of octenes with di-n-octylaluminium hydride [HAl(Oct)2], tri-n-octylaluminium [Al(Oct)3] and sec-octylaluminium species have been studied as individual steps in a putative aluminium based contrathermodynamic olefin isomerisation process. While elimination of 1-octene from [Al(Oct)3] is energetically unfavourable, the process is driven by high temperature vacuum distillation, leading to very high selectivity to 1-octene (>97%). At high conversions the [HAl(Oct)2] so obtained exists predominately as hydride-bridged cyclic oligomers, whereas at low conversion the mixed alkyl/hydride-bridged dimer [(Oct)2Al(µ-H)(µ-Oct)Al(Oct)2] is the major species. Di-n-octylaluminium hydride recovered after olefin elimination may be recycled and is active toward re-insertion of octenes. Internal octenes (cis- and trans-2-, 3- and 4-octene) only partially insert however, and even after prolonged heating there is no significant secondary to primary alkyl isomerisation evident.

High activity acetylene polymerisation with a bis(imino)pyridine iron(II) catalyst.

A catalyst system composed of a 2,6-bis(arylimino)pyridineiron(II) dichloride complex and methylaluminoxane is found to be extremely active for acetylene polymerisation. The formation of poly(acetylene) gels and surface films occurs at very low catalyst concentrations, around three orders of magnitude lower than traditional catalyst systems.

Controlled synthesis of (S,S)-2,7-diaminosuberic acid: a method for regioselective construction of dicarba analogues of multicystine-containing peptides.

A method to facilitate regioselective formation of multiple dicarba isosteres of cystine is described. A sequence of ruthenium-catalyzed cross metathesis and rhodium-catalyzed hydrogenation of nonproteinaceous allylglycine derivatives has been developed to achieve high-yielding and unambiguous formation of diaminosuberic acid derivatives. Allylglycine derivatives readily undergo ruthenium-catalyzed metathesis and hydrogenation to yield diaminosuberic acid derivatives in near quantitative yield. Under the same experimental conditions, prenylglycine was found to be inert to both Grubbs' and Wilkinson's catalyzed metathesis and hydrogenation, respectively, but was readily activated for metathesis via cross metathesis with Z-butene. Subsequent cross metathesis of the metathesis-formed crotylglycine derivative, followed by hydrogenation, yielded the second diaminosuberic acid derivative in excellent yield.