Kinetics of the acid hydrolysis of cellulose found in paper refuse

This review presents an overview of the initial targeted chemical processing stages for conversion of lignocellulosic biomass to platform molecules that serve as intermediates for the production of carbonbased fuels and chemicals. We identify four classes of platform molecules that can be obtained in an initial chemical processing step: (i) sugars, (ii) dehydration products, (iii) polyols and (iv) lignin monomers. Special emphasis is placed on reporting and comparing parameters that affect process economics and/or sustainability, including product yields, amount of catalyst used, processing conditions, and product concentrations. We discuss the economic trade-offs associated with choices related to these parameters, depending on the product that is targeted. We also address the effects of real biomass on the ability to recover, recycle, and potentially regenerate catalysts and solvents used in the biomass conversion processes.

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“…To achieve yields above 60% with 1% H 2 SO 4 , high temperatures (>500 K) and short residence time (<1 min) are required 50,51 ( Fig. 2A).…”

Section: Hydrothermal Processesmentioning

confidence: 99%

Targeted chemical upgrading of lignocellulosic biomass to platform molecules

2014

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“…Also, several later studies are based on Saemans model. In papers by Fagan et al [3], Thompson and Grethlein [4], and Franzidis et al [5] a plug-flow reactor was used to study the kinetics of the hydrolysis reaction of Kraft paper slurries, Solka Floc as well as filter paper. Also, Malester and co-workers [6,7] were using Saemans model when the kinetics of dilute hydrolysis of cellulose originating from municipal solid wastes was investigated in a batch reactor.…”

Section: Introductionmentioning

confidence: 99%

Heterogeneously catalyzed conversion of nordic pulp to levulinic and formic acids

Ahlkvist

Wärnå

Salmi

et al. 2016

Reac Kinet Mech Cat

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Herein, one-pot conversion of cellulose to platform chemicals, formic and levulinic acids was demonstrated. The catalyst selected was an affordable, acidic ion-exchange resin, Amberlyst 70, whereas the cellulose used was sulfite cellulose delivered by a Swedish pulp mill. Furthermore, in an attempt to better understand the complex hydrolysis network of the polysaccharide, kinetic experiments were carried out to pinpoint the optimal reaction conditions with an initial substrate concentration of 0.7-6.0 wt% and a temperature range of 180-200°C. Higher temperatures could not be used due to the limitations in the thermal stability of the catalyst. Overall, maximum theoretical yields of 59 and 68 mol% were obtained for formic and levulinic acid, respectively. The parameters allowing for the best performance were reaction temperature of 180°C and initial cellulose concentration of 0.7 wt%. After studying the behavior of the system, a simplified reaction network in line with a mechanistic approach was developed and found to follow first order reaction kinetics. A satisfactory fit of the model to the experimental data was achieved (97.8 % degree of explanation). The catalyst chosen exhibited good mechanical strength under the experimental conditions and thus, a route providing green platform chemicals from soft wood pulp from coniferous trees (mixture of Scots Pine and Norway Spruce) was demonstrated.

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“…Kinetics of acid-catalyzed cellulose hydrolysis under an aqueous environment has been studied (Saeman, 1945;Fagan et al, 1971;Thompson and Grethlein, 1979). A two consecutive firstorder reaction model was proposed for the dilute-acid catalyzed cellulose hydrolysis, and experimental data were well fit into the model (Saeman, 1945).…”

Section: Introductionmentioning

confidence: 99%

“…Because cellulose was not solubilized and physio-chemical properties of cellulose varied substantially during the course of the experiment, it turned out challenging to reach an insightful view for the hydrolysis process. Thus, kinetic studies based on this early model led to different kinetic parameters (Fagan et al, 1971;Thompson and Grethlein, 1979). Moreover, it was difficult to link those kinetic parameters to detailed reaction mechanism.…”

Section: Introductionmentioning

confidence: 99%