Pyrolysis of sorghum bagasse biomass into bio-char and bio-oil products

The transformation of renewable biomass into valuable products as alternatives to fossil fuels is essential for sustainable energy in sustainable society. This work systematically investigates the pyrolysis of sorghum bagasse biomass into bio-char and bio-oil products and studies the effect of temperature (623–823 K) on the conversion of sorghum bagasse and products yields. The physicochemical properties of bio-char were thoroughly studied using powder X-ray diffraction, elemental analysis (CHNSO), scanning electronic microscope, calorific value (CV), and Fourier transform infrared (FTIR) spectroscopy techniques. Also, gas chromatography–mass spectrometry (GC–MS), CV, and FTIR were used to understand the properties of bio-oil. The results obtained indicate that an increase in the pyrolysis temperature from 623 to 823 K leads to a decrease in the bio-char yield from 42.55 to 30.38%. On the other hand, the maximum bio-oil yield of 15.94% was obtained at 723 K. The bio-char obtained at 673 and 773 K was found by FTIR analysis to be composed of a highly ordered aromatic carbon structure. The calorific value of bio-oil, which contains a greater amount of acidic compounds, was found to be 6740 kcal/kg. The GC–MS analyses revealed the presence of octadecenoic acid, p-cresol, 2,6-dimethoxy phenol, 4-ethyl 2-methoxy phenol, phenol, o-guaiacol, and octadecanoic acid in the bio-oil obtained from the pyrolysis of sorghum bagasse biomass. The present study provides useful information for understanding the quality of bio-oil and bio-char obtained from high biomass sorghum bagasse.     

Reactions of alkynes with trisubstituted (Z)-bromoalkenyl-pinacolboronates towards the synthesis of 1,2,4,6-tetrasubstituted benzenes

Treatment of trisubstituted (Z)-bromoalkenyl-pinacolboronates with terminal alkynes in the presence of cuprous iodide, palladium(0) tetrakis(triphenylphosphine) and Hünig’s base leads to the formation of 1,2,4,6-tetrasubstituted aromatic compounds in a one-pot fashion. Substrate scope was shown for three trisubstituted (Z)-bromoalkenyl-pinacolboronates and four terminal alkynes.     

Palladium(II)–copper(I) mediated homotrimerization and homotetramerization of terminal alkynes

Alkyne homocoupling is commonly observed in cross coupling reactions; however, self trimerization and homotetramerization of alkynes to form branched products through cross-coupling reactions are rarely reported. We describe herein homotrimerization and homotetramerization of terminal alkynes under the Sonogashira reaction conditions that gave the corresponding modified enediynes. Substrate scope for this reaction was explored.     

Ag Loaded on SiO2 as an Efficient and Recyclable Heterogeneous Catalyst for the Synthesis of Chloro‐8‐substituted‐9H‐purines

Ag support on silica has been used as an effective heterogeneous catalyst for the facile synthesis of chloro‐8‐substituted‐9H‐purine derivatives via the one‐pot reaction of 6‐chloro‐pyrimidines and substituted acids. The title compounds were formed as excellent yields with short reaction time under eco‐friendly conditions. The prepared catalyst (Ag/SiO₂) can be reused for a number of times with insignificant loss in its activity. This route has the advantage of being a cost‐effective, readily available, easy workup procedure.     

Covalent Modification of Organo‐Functionalized Graphene Oxide and its Scope as Catalyst for One‐Pot Pyrazolo‐Pyranopyrimidine Derivatives

The surface of graphene oxide (GO) was modified using [3‐(2‐aminoethylamino)propyl]trimethoxysilane (diamine), which exhibited excellent catalytic activity for one‐pot multicomponent reactions. The newly synthesized material was fully characterized by various instrumental techniques including Fourier‐transfer infrared (FTIR) and Raman spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The instrumental analysis confirmed the successful grafting of organic amine functional groups onto the graphene oxide surface. The diamine‐functionalized GO proved to be an excellent catalyst for the synthesis of pyrazolo‐pyranopyrimidine derivatives with 93 % yield and high selectivity. The catalytic activity almost remained unaltered up to three cycles. The newly synthesized pyrazolo‐pyranopyrimidine derivatives have potential use as scaffolds in designing new pharmaceutical products.     

Optimization studies of photo-neutron production in high-<Emphasis Type="Italic">Z</Emphasis> metallic targets using high energy electron beam for ADS and transmutation

Monte Carlo calculations have been performed using MCNP code to study the optimization of photo-neutron yield for different electron beam energies impinging on Pb, W and Ta cylindrical targets of varying thickness. It is noticed that photo-neutron yield can be increased for electron beam energies ≥100 MeV for appropriate thickness of the target. It is also noticed that it can be maximized by further increasing the thickness of the target. Further, at higher electron beam energy heat gradient in the target decreases, which facilitates easier heat removal from the target. This can help in developing a photoneutron source based on electron LINAC by choosing appropriate electron beam energy and target thickness to optimize the neutron flux for ADS, transmutation studies and as high energy neutron source etc. Photo-neutron yield for different targets, optimum target thickness and photo-neutron energy spectrum and heat deposition by electron beam for different incident energy is presented.