Acetylation of sugarcane bagasse hemicelluloses under mild reaction conditions by using NBS as a catalyst

2004 ◽  
Vol 92 (1) ◽  
pp. 53-61 ◽  
Author(s):  
Xaio-Feng Sun ◽  
Run-Cang Sun ◽  
Li Zhao ◽  
Jing-Xia Sun
Keyword(s):  
Sugarcane Bagasse ◽  
Reaction Conditions

The Preparation of Sugarcane Bagasse Microcrystaline Cellulose in Subcritical Water/CO2

2011 ◽  
Vol 396-398 ◽  
pp. 1769-1772
Author(s):  
Ke Lin Huang ◽  
Ben Wang ◽  
Xiao Yu Peng ◽  
Ze Fen Wang ◽  
Ke Xian Li ◽  
...  
Keyword(s):  
Reaction Time ◽  
Sugarcane Bagasse ◽  
Reaction Temperature ◽  
Subcritical Water ◽  
Reaction Conditions ◽  
Reaction Pressure ◽  
Good Thermal Stability ◽  
Solid Ratio ◽  
Optimum Reaction ◽  
Ft Ir

Sugarcane bagasse microcrystalline cellulose (SBMC) was first prepared under subcritical Water/CO2 by degradation of sugarcane bagasse cellulose (SBC). The obtained products were characterized by FT-IR, XRD and TGA and the results showed that the amorphous parts of SBC was easily decomposed, and yet the crystal parts kept a good form all along during the degradation, which demonstrated SBMC had good thermal stability. Furthermore, the reaction temperature, reaction time, reaction pressure and liquid-solid ratio were systematically investigated during the work. The optimum reaction conditions are as follows: the reaction temperature was 200°C; the reaction time was 60 min; the reaction pressure was 2 MPa and the liquid-solid ratio was 40:1.

scholarly journals Ultrasonically-Assisted Dissolution of Sugarcane Bagasse during Dilute Acid Pretreatment: Experiments and Kinetic Modeling

Energies ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5627
Author(s):  
Deslin Nadar ◽  
Kubendren Naicker ◽  
David Lokhat
Keyword(s):  
Reaction Time ◽  
Sugarcane Bagasse ◽  
Reaction Vessel ◽  
Dilute Acid Pretreatment ◽  
Dilute Acid ◽  
Acid Pretreatment ◽  
Reaction Conditions ◽  
Physicochemical Processes ◽  
Solids Loading ◽  
Mass Losses

Ultrasonic irradiation is known to enhance various physicochemical processes. In this work, the effect of ultrasound on the dissolution of sugarcane bagasse was studied, with the specific aims of quantifying the effect at low solids loading and mild reaction conditions, and determining whether the enhancement of dissolution by ultrasound is independent of temperature. The effects of agitation speed, reaction time, and sonication were examined on the dissolution of the biomass substrate at varying reaction temperatures during the pretreatment process. Sugarcane bagasse was mixed with a 0.3 M solution of sulfuric acid in a reaction vessel to undergo pretreatment. A kinetic model was applied to the mass dissolution of the biomass, as sonicated runs showed higher mass losses at each reaction time, compared to the non-sonicated runs. The ultrasonic enhancement in mass dissolution was seen to increase for an increase in the reaction time. It was observed that the induction period for the dissolution was eliminated by the application of ultrasound. Ultrasound was found to be more effective than temperature at enhancing mass dissolution at low solids loadings, and the effect of ultrasound was also found to be dependent on the temperature employed.

scholarly journals Catalytic condensation of depithed sugarcane bagasse derived levulinic acid into diphenolic acid

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2235-2248
Author(s):  
Lethiwe Debra Mthembu ◽  
David Lokhat ◽  
Nirmala Deenadayalu
Keyword(s):  
Sulfuric Acid ◽  
Sugarcane Bagasse ◽  
Levulinic Acid ◽  
Methanesulfonic Acid ◽  
Environmentally Benign ◽  
Catalyst Loading ◽  
Optimum Conditions ◽  
Reaction Parameters ◽  
Reaction Conditions ◽  
Catalytic Condensation

Levulinic acid (LA) is a platform chemical that can be produced from biomass. Diphenolic acid (DPA) is a derivative of LA with the potential to replace bisphenol A, a plasticizer. To determine the optimum conditions for DPA production, commercial LA was used with a mild environmentally benign acid, namely, methanesulfonic acid (MsOH). The optimized reaction parameters were time (6 h), temperature (75 °C), and catalyst loading (5.5 g), yielding 65.8% DPA at 90% LA conversion. The response surface methodology (RSM) study indicated that the temperature had the most significant effect on DPA yield, followed by time and catalyst loading. The analysis of variance (ANOVA) revealed that the model was able to satisfactorily predict the DPA yield. To determine the effect of catalyst on DPA production from commercial LA, ionic liquids (ILs), MsOH, and sulfuric acid were used. IL catalysts produced 59 to 68% of DPA, MsOH produced 65.6% of DPA, and sulfuric acid produced the maximum DPA of 74%. The study of LA: phenol ratio revealed that more reactants (2:5) yielded the most DPA (86.35%). The optimized reaction conditions were then used to produce DPA from LA derived from depithed sugarcane bagasse (DSB), which yielded 64.5% of DPA.

Undecagold labeling of tRNA

1991 ◽  
Vol 49 ◽  
pp. 44-45
Author(s):  
James F. Hainfeld ◽  
Kyra M. Alford ◽  
Mathias Sprinzl ◽  
Valsan Mandiyan ◽  
Santa J. Tumminia ◽  
...  
Keyword(s):  
High Resolution ◽  
Transmission Electron Micrograph ◽  
Anticodon Loop ◽  
Electron Micrograph ◽  
Reaction Conditions ◽  
Scanning Transmission Electron ◽  
Transmission Electron ◽  
Scanning Transmission

The undecagold (Au11) cluster was used to covalently label tRNA molecules at two specific ribonucleotides, one at position 75, and one at position 32 near the anticodon loop. Two different Au11 derivatives were used, one with a monomaleimide and one with a monoiodacetamide to effect efficient reactions.The first tRNA labeled was yeast tRNAphe which had a 2-thiocytidine (s2C) enzymatically introduced at position 75. This was found to react with the iodoacetamide-Aun derivative (Fig. 1) but not the maleimide-Aun (Fig. 2). Reaction conditions were 37° for 16 hours. Addition of dimethylformamide (DMF) up to 70% made no improvement in the labeling yield. A high resolution scanning transmission electron micrograph (STEM) taken using the darkfield elastically scattered electrons is shown in Fig. 3.

Dimensionally-Controlled Hydrothermal Tm3+-doped Oxidic Nanocrystals and Their Photoluminescence Properties

2010 ◽  
Vol 1247 ◽  
Author(s):  
Rocío Calderón-Villajos ◽  
Carlos Zaldo ◽  
Concepción Cascales
Keyword(s):  
Single Crystals ◽  
Fluorescence Lifetimes ◽  
Photoluminescence Properties ◽  
Reaction Conditions ◽  
Hydrothermal Processes ◽  
Bulk Single Crystals ◽  
Template Free ◽  
Reaction Media

AbstractControlled reaction conditions in simple, template-free hydrothermal processes yield Tm-Lu2O3 and Tm-GdVO4 nanocrystals with well-defined specific morphologies and sizes. In both oxide families, nanocrystals prepared at pH 7 reaction media exhibit photoluminescence in ∼1.95 μm similar to bulk single crystals. For the lowest Tm3+ concentration (0.2 % mol) in GdVO4 measured 3H4 and 3F4 fluorescence lifetimes τ are very near to τrad.

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