A Systematic Study on the Utilization of Inorganic Salts as Catalyst for the Conversion of Xylose to Furfural

The utilization of biomass-waste such as sugar-bagasse,water-hyacynth and palm-oil-fiber as alternative sources for transportation fuels and platform-chemicals is a very active research field. Furfural(FF) is one-of-the-13top platform-chemicals that may be converted to derivatives such as furfuryl-alcohol,furoic-acid and furan with wide applications in the gasoline,diesel and jet-fuel blending-pool. Many studies have been conducted in the mechanism and the kinetics of FF-formation from xylose since the 1940s to maximize FF-yield and to reduce FF-decomposition to undesired-products. Previous studies showed that inorganic-salt gives positive effects on the FF-yield but systematic studies are lacking. Based on it, 60salts were screened in the hydrolysis of 0.1M xylose-aqueous-solution (T=180°C,90minutes,batch). The maximum FF-yield was 53mol% using 5mM-Fe2(SO4)3. The highest FF-selectivity was at 84mol% using 5mM-NaCl, though at low xylose-conversion(35 mol%-FF-yield). Some transition metal-chloride i.e.FeCl2,CuCl2,SnCl2 showed interesting FF-yields(48-50%) and selectivity(58-65%) indicating interesting roles of ion Fe3+ and Cl-. Subsequent studies of two salts i.e.Fe2(SO4)3 and FeCl3(5mM) in combination with HCl and H2SO4(0.1M) were investigated(0.1M-xylose,T=150°C,0-270 min). The result shows that salts increase no FF-yields for H2SO4 but increase the reaction-rate. In contrast, Fe2(SO4)3 increase no yield nor reaction-rate for HCl-catalyzed-system. In conclusion, the inorganic-salts catalyse xylose-conversion to furfural but best results were obtained using HCl without additional salts

Kinetic Studies on the Conversion of Levoglucosan to Glucose in Water Using Bronsted Acids as the Catalysts

Fast pyrolysis is as a promising and versatile technology to depolymerize and concentrate sugars from lignocellulosic biomass. The pyrolysis liquids produced contain considerable amounts of levoglucosan (1,6-anhydro-beta-D-glucopyranose), which is an interesting source for glucose (GLC). Here, we report a kinetic study on the conversion of levoglucosan (LG) to GLC in water using sulfuric and acetic acid as the catalysts under a wide range of conditions in a batch setup. The effects of the initial LG loading (0.1-1 M), sulfuric and acetic acid concentrations (0.05-0.5 M and 0.5-1 M, respectively), and reaction temperatures (80-200 degrees C) were determined. Highest GLC yields were obtained using sulfuric acid (98 mol %), whereas the yields were lower for acetic acid (maximum 90 mol %) due to the formation of byproducts such as insoluble polymers (humins). The experimental data were modeled using MATLAB software, and relevant kinetic parameters were determined. Good agreement between experimental and model was obtained when assuming that the reaction is first order with respect to LG. The activation energies were 123.4 kJ mol(-1) and 120.9 kJ mol(-1) for sulfuric and acetic acid, respectively

Volatile State Mathematical Models for Predicting Components in Biomass Pyrolysis Products

Volatile state mathematical models for quantifying the chemical components in volatile biomass pyrolysis products were developed. The component mass yield Yi rate depends linearly on its pseudo kinetic constant and the remaining mass yield. The mass fraction rate of each component was modeled from the derivation of its mass yield rate equation. A new mathematical model equation was successfully developed. The involved variables are: biomass number, temperature, heating rate, pre-exponential factor, and pseudo activation energy related to each component. The component mass fraction yi and the mass yield were predicted using this model within a temperature range. Available experimental pyrolysis data for beechwood and rice husk biomass were used to confirm the developed model. The volatile products were separated into bio-pyrolysis gas (BPG) and a bio-pyrolysis oil (BPO). Five components in the BPG and forty in the BPO were quantified. The pseudo activation energy for each pseudo chemical reaction for a specific component was modeled as a polynomial function of temperature. The component mass fraction and yield are quantifiable using this developed mathematical model equation within a temperature range. The predicted component mass fractions and yields agreed excellently with the available experimental data

Volatile State Mathematical Models for Predicting Components in Biomass Pyrolysis Products

Volatile state mathematical models for quantifying the chemical components in volatile biomass pyrolysis products were developed. The component mass yield Yi rate depends linearly on its pseudo kinetic constant and the remaining mass yield. The mass fraction rate of each component was modeled from the derivation of its mass yield rate equation. A new mathematical model equation was successfully developed. The involved variables are: biomass number, temperature, heating rate, pre-exponential factor, and pseudo activation energy related to each component. The component mass fraction yi and the mass yield were predicted using this model within a temperature range. Available experimental pyrolysis data for beechwood and rice husk biomass were used to confirm the developed model. The volatile products were separated into bio-pyrolysis gas (BPG) and a bio-pyrolysis oil (BPO). Five components in the BPG and forty in the BPO were quantified. The pseudo activation energy for each pseudo chemical reaction for a specific component was modeled as a polynomial function of temperature. The component mass fraction and yield are quantifiable using this developed mathematical model equation within a temperature range. The predicted component mass fractions and yields agreed excellently with the available experimental data

Experimental and Modeling Studies on the Conversion of Inulin to 5-Hydroxymethylfurfural Using Metal Salts in Water

Inulin, a plant polysaccharide consisting of mainly d-fructose units, is considered an interesting feed for 5-hydroxymethylfurfural (HMF), a top 12 bio-based chemical. We here report an exploratory experimental study on the use of a wide range of homogeneous metal salts as catalysts for the conversion of inulin to HMF in water. Best results were obtained using CuCl2. Activity-pH relations indicate that the catalyst activity of CuCl2 is likely related to Lewis acidity and not to Brönsted acidity. The effects of process conditions on HMF yield for CuCl2 were systematically investigated and quantified using a central composite design (160–180 °C, an inulin loading between 0.05 and 0.15 g/mL, CuCl2 concentration in range of 0.005–0.015 M, and a reaction time between 10 and 120 min). The highest experimental HMF yield in the process window was 30.3 wt. % (39 mol %, 180 °C, 0.05 g/mL inulin, 0.005 M CuCl2 and a reaction time of 10 min). The HMF yields were modelled using non-linear, multi variable regression and good agreement between experimental data and model were obtained

Studi Kondisi Operasi dalam Pemisahan Asam Laktat dari Produk Konversi Katalitik Tandan Kosong Sawit Melalui Esterifikasi-Hidrolisis

Lactic acid is a platform chemical that is usually used to form various chemical products. Nowadays, the need of lactic acid is increasingly high especially for bio-based chemical as a substitute for petroleum-based one. Catalytic chemical conversion is seemingly potential to substitute the bioconversion pathway. This research aims to determine the best operating condition for separating lactic acid from its mixture (the catalytic conversion product of oil palm empty fruit bunch) by esterification-hydrolysis in order to produce the highest yield and purity. The esterification of the mixture was carried out by using n-butanol as a solvent and wet Amberlyst-15 as a catalyst. The esterification process was conducted by reacting n-butanol and lactic acid for 6 hours in a batch reactor. Hydrolysis was then followed by reacting organic phase as an esterification product and water in batch reactor system for 4 hours. The result showed that the higher reactant volume ratio, temperature, and catalyst concentration were used, the higher yield of both esterification and hydrolysis products would be. The highest esterification yield of 98.64%-w/w was achieved when the temperature was at 90oC, with a reactant volume ratio of 4, and the catalyst concentration of 2.5%-w/w. Moreover, the experiment results showed that the highest hydrolysis yield of 98.64%-w/w was achieved by the temperature of 90 oC, the reactant volume ratio of 20, and the catalyst concentration of 2.5%-w/w. It was revealed that the most significant variable for esterification was reactant volume ratio while both reactant volume ratio and temperature become the prominent variables for hydrolysis counterpart. Additionally, another modified method of separation was conducted by applying reactive distillation. This modified process increased the hydrolysis yield up to 82.34%-w/w by using pure butyl lactate as feed while the usage of the catalytic butyl lactate as feed could produce lactic acid with the yield of 74.01%-w/w. A B S T R A KAsam laktat adalah bahan kimia antara yang bermanfaat untuk pembentukan berbagai macam produk kimia. Permintaan asam laktat dewasa ini sangat tinggi terutama sebagai bahan kimia berbasis alam yang digunakan sebagai substitusi untuk penggunaan bahan kimia tak terbarukan. Terdapat banyak alternatif proses yang sudah dilakukan oleh peneliti untuk menemukan metode alternatif yang efektif sebagai pengganti proses fermentasi dan konversi katalitik merupakan proses yang berpotensi untuk diaplikasikan. Penelitian ini bertujuan untuk menentukan kondisi operasi yang menghasilkan perolehan asam laktat tinggi pada reaksi esterifikasi-hidrolisis asam laktat dari produk reaksi katalitik tandan kosong sawit menggunakan n-butanol p.a., dan katalis Amberlyst-15 basah. Esterifikasi dilakukan dengan mereaksikan n-butanol dan umpan hasil konversi katalitik tandan kosong sawit selama 6 jam. Hidrolisis dilakukan dengan mereaksikan air dan fase organik esterifikasi selama 4 jam. Hasil menunjukkan semakin tinggi temperatur reaksi, rasio volume reaktan, dan konsentrasi katalis, semakin tinggi perolehan asam laktat esterifikasi dan hidrolisis yang dihasilkan. Perolehan butil laktat tertinggi pada reaksi esterifikasi diperoleh sebesar 98,64%-b/b pada kondisi 90 oC, rasio volume 4 dan konsentrasi katalis 2,5%-b/b. Perolehan asam laktat tertinggi pada reaksi hidrolisis diperoleh sebesar 67,97%-b/b pada kondisi 90 oC, rasio volume 20 dan konsentrasi katalis 2,5%-b/b. Variabel signifikan pada esterifikasi adalah rasio volume reaktan, sedangkan pada hidrolisis adalah rasio volume reaktan dan temperatur. Penggunaan distilasi reaktif pada hidrolisis mampu meningkatkan perolehan asam laktat hingga 82,34%-b/b untuk butil laktat murni sebagai umpan dan 74,01%-b/b untuk butil laktat katalitik sebagai umpan

Influence of reaction conditions on the composition of liquid products from two-stage catalytic hydrothermal processing of lignin.

The influence of reaction conditions on the composition of liquid products during two-stage hydrothermal conversion of alkali lignin has been investigated in a batch reactor. Reactions were carried out in the presence of formic acid (FA) and Pt/Al2O3 catalyst. The two different sets of reaction conditions involved alternative reaction times of 1 h and 5 h at 265 °C and 350 °C, respectively. These provided different contributions to reaction severity, which affected the compositions of liquid products. Yields of liquid products reached up to 40 wt% (on lignin feed basis) in the presence of FA under the less severe reaction condition. With 5 h reaction time at 350 °C, alkylphenols, alkylguaiacols and hydrocarbons were the dominant liquid products. However, with 5 h reaction time at 265 °C, phenol and methanol became dominant. The two-stage hydrothermal process led to improved lignin conversion, with the potential to manipulate the liquid product range

Experimental and Kinetic Modeling Studies on the Conversion of Sucrose to Levulinic Acid and 5-Hydroxymethylfurfural Using Sulfuric Acid in Water

We here report experimental and kinetic modeling studies on the conversion of sucrose to levulinic acid (LA) and 5-hydroxymethylfurfural (HMF) in water using sulfuric acid as the catalyst. Both compounds are versatile building blocks for the synthesis of various biobased (bulk) chemicals. A total of 24 experiments were performed in a temperature window of 80–180 °C, a sulfuric acid concentration between 0.005 and 0.5 M, and an initial sucrose concentration between 0.05 and 0.5 M. Glucose, fructose, and HMF were detected as the intermediate products. The maximum LA yield was 61 mol %, obtained at 160 °C, an initial sucrose concentration of 0.05 M, and an acid concentration of 0.2 M. The maximum HMF yield (22 mol %) was found for an acid concentration of 0.05 M, an initial sucrose concentration of 0.05 M, and a temperature of 140 °C. The experimental data were modeled using a number of possible reaction networks. The best model was obtained when using a first order approach in substrates (except for the reversion of glucose) and agreement between experiment and model was satisfactorily. The implication of the model regarding batch optimization is also discussed

Sodium ion interactions with aqueous glucose: Insights from quantum mechanics, molecular dynamics, and experiment

In the last several decades, significant efforts have been conducted to understand the fundamental reactivity of glucose derived from plant biomass in various chemical environments for conversion to renewable fuels and chemicals. For reactions of glucose in water, it is known that inorganic salts naturally present in biomass alter the product distribution in various deconstruction processes. However, the molecular-level interactions of alkali metal ions and glucose are unknown. These interactions are of physiological interest as well, for example, as they relate to cation-glucose cotransport. Here, we employ quantum mechanics (QM) to understand the interaction of a prevalent alkali metal, sodium, with glucose from a structural and thermodynamic perspective. The effect on B-glucose is subtle: a sodium ion perturbs bond lengths and atomic partial charges less than rotating a hydroxymethyl group. In contrast, the presence of a sodium ion significantly perturbs the partial charges of α-glucose anomeric and ring oxygens. Molecular dynamics (MD) simulations provide dynamic sampling in explicit water, and both the QM and the MD results show that sodium ions associate at many positions with respect to glucose with reasonably equivalent propensity. This promiscuous binding nature of Na + suggests that computational studies of glucose reactions in the presence of inorganic salts need to ensure thorough sampling of the cation positions, in addition to sampling glucose rotamers. The effect of NaCl on the relative populations of the anomers is experimentally quantified with light polarimetry. These results support the computational findings that Na + interacts similarly with a- and B-glucose

Recent advances in hydrothermal carbonisation:from tailored carbon materials and biochemicals to applications and bioenergy

Introduced in the literature in 1913 by Bergius, who at the time was studying biomass coalification, hydrothermal carbonisation, as many other technologies based on renewables, was forgotten during the "industrial revolution". It was rediscovered back in 2005, on the one hand, to follow the trend set by Bergius of biomass to coal conversion for decentralised energy generation, and on the other hand as a novel green method to prepare advanced carbon materials and chemicals from biomass in water, at mild temperature, for energy storage and conversion and environmental protection. In this review, we will present an overview on the latest trends in hydrothermal carbonisation including biomass to bioenergy conversion, upgrading of hydrothermal carbons to fuels over heterogeneous catalysts, advanced carbon materials and their applications in batteries, electrocatalysis and heterogeneous catalysis and finally an analysis of the chemicals in the liquid phase as well as a new family of fluorescent nanomaterials formed at the interface between the liquid and solid phases, known as hydrothermal carbon nanodots