The effect of pretreatment on methanesulfonic acid-catalyzed hydrolysis of bagasse to levulinic acid, formic acid, and furfural

A major challenge that must be overcome for the commercial production of levulinic acid from lignocellulosics is to reduce equipment blockage and corrosion. Methanesulfonic acid (MSA), a relatively low corrosive acid, was used to produce organic acids and furfural from pretreated sugarcane bagasse. In general, the type of pretreatment did not affect levulinic acid yield, though it affected furfural yield. However, soda pretreated bagasse produced the highest yields of levulinic acid (∼75 mol%) and furfural (∼85 mol%), albeit under optimized conditions. Hydrolysis residue consists primarily of lignin that has been modified and/or condensed to humic substances, fatty acids, and oligomeric sugars. A conceptual biorefinery utilizing 1 ton of dry bagasse, alkaline-pretreatment, and MSA as a catalyst produced 165 kg soda lignin, 190 kg and 89 kg of levulinic acid and formic acid respectively, and 40 kg furfural

Bubble rise phenomena through Newtonian and non-Newtonian fluids

The characteristics of bubble rise phenomenon in three liquids were investigated and are reported here. The experimental rig consists of two transparent cylindrical columns – one a polycarbonate tube of 125 mm diameter and the other an acrylic tube of 400 mm diameter. The rig also consists of a lifting device designed to hold a video camera for taking bubble images. Water and two non-Newtonian fluids (0.025% and 0.045% by weight of polyacrylamide solutions) were used in this study. The smaller polycarbonate tube was used to study the velocity and the drag coefficient under vacuum. The bigger acrylic tube was used to study the influence of the size of bubbles

Structural characteristics of bagasse furfural residue and its lignin Component. A NMR, Py-GC/MS, and FTIR study

Commercial furfural, an important platform chemical, is produced from acid hydrolysis of lignocellulosic biomass. The manufacturing processes are inherently inefficient, and so it is necessary to value add to substantial amounts of residue obtained. The structural features of bagasse furfural residue and the lignins extracted from it by three NaOH treatments have been studied in order to understand the transformations that occurred by these treatments. 2D-NMR and Py-GC/MS of the furfural residue revealed that it contains mostly lignin and depolymerized cellulose moieties and the complete absence of xylans as a result of their hydrolysis during the furfural production process. In addition, the analyses revealed that the furfural residue contains 44% of H-type lignin units, in comparison to 11% for bagasse, and most of the lignin interunit linkages present in bagasse have disappeared. The pyrograms show that the furfural residue produced unusually high phenol content, which was attributed to the high levels of “H-type” units present in this lignin. The proportion of functional groups, particularly total OH aliphatic groups, where significantly lower in the extracted lignins compared to soda lignin obtained by the normal pulping process. The highest severity of the NaOH extraction process reduced the amount of reactive functional groups present in the lignin, though the S/G ratios of ∼1.1 were independent of the extraction method. The three lignins have high proportions of “H-units” (around 36–37%), which gives them special properties for different applications, particularly in the production of phenolic resins

An analysis of skin prick test reactions in 656 asthmatic patients.

Of 656 asthmatic patients referred specifically for allergy assessments, 544 (84 percent) gave positive immediate skin prick tests to at least one of 22 common allergens used routinely. Comparison of these skin test positive patients with the 102 (16 percent) who were skin test negative showed a number of significant differences. The majority of the skin test positive patients (52 percent) were less than 10 years old at the time of onset of the asthma, whereas, of the skin test negative patients, 56 percent were aged over 30 years at the time of onset. Seventy per cent report rhinitis compared with 48 per cent of the skin test negative patients, and 29 per cent reported infantile eczema compared with 9 per cent. Symptoms attributed to house dust, pollens, and animals were noted two to three times more frequently by the skin test positive patients, while corticosteroid drugs had been used more commonly by the skin test negative patients (45 percent compared with 35 percent). No significant differences were observed with the other factors studied, namely, history of urticaria or angio-oedema, family history of "allergic" disease, and awareness of sensitivity to foods, aspirin or penicillin. Prick test reactions in the skin test positive patients were most commonly seen to house dust or the acarine mite, Dermatophagoides farinae (82 percent), followed by pollens (66 percent), animal danders (38 percent), foods (16 percent), Aspergillus fumigatus (16 percent), and other moulds (21 percent). There was a highly significant association of positive history with positive prick test for all allergens studied