scholarly journals The Impact of Biomass and Acid Loading on Methanolysis during Two-Step Lignin-First Processing of Birchwood

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 750
Author(s):  
Panos D. Kouris ◽  
Xiaoming Huang ◽  
Xianhong Ouyang ◽  
Dannie J. G. P. van Osch ◽  
Geert J. W. Cremers ◽  
...  
Keyword(s):  
Quantum Coherence ◽  
Gel Permeation Chromatography ◽  
Elevated Pressure ◽  
High Reactivity ◽  
Sugar Release ◽  
Cellulose Pulp ◽  
Biomass Ratio ◽  
Reductive Treatment ◽  
The Impact ◽  
Acid Loading

We optimized the solvolysis step in methanol for two-step lignin-first upgrading of woody biomass. Birchwood was first converted via sulfuric acid methanolysis to cellulose pulp and a lignin oil intermediate, which comprises a mixture of lignin oligomers and C5 sugars in the methanol solvent. The impact of reaction temperature (140–200 °C), acid loading (0.24–0.81 wt%, dry biomass), methanol/biomass ratio (2.3/1–15.8/1 w/w) and reaction time (2 h and 0.5 h) was investigated. At high biomass loadings (ratio < 6.3/1 w/w), operation at elevated pressure facilitates delignification by keeping methanol in the liquid phase. A high degree of delignification goes together to a large extent with C5 sugar release, mostly in the form of methyl xylosides. Gel permeation chromatography and heteronuclear single quantum coherence NMR of lignin fractions obtained at high acid (0.81 wt%) and low biomass (15.8/1 w/w) loading revealed extensive cleavage of β-O-4′ bonds during acidolysis at 180 °C for 2 h. At an optimized methanol/biomass ratio of 2.3/1 w/w and acid loading (0.24 wt%), more β-O-4′ bonds could be preserved, i.e., about 33% after 2 h and 47% after 0.5 h. The high reactivity of the extracted lignin fragments was confirmed by a second hydrogenolysis step. Reductive treatment with Pd/C under mild conditions led to disappearance of ether linkages and molecular weight reduction in the hydrotreated lignin oil.

scholarly journals Influence of Reaction Parameters on the Gelation of Silanised Linseed Oil

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5376
Author(s):  
Ewelina Depczyńska ◽  
Waldemar Perdoch ◽  
Bartłomiej Mazela
Keyword(s):  
Molar Mass ◽  
Linseed Oil ◽  
Gel Permeation Chromatography ◽  
Elevated Pressure ◽  
High Reactivity ◽  
Reaction Products ◽  
1H And 13C Nmr ◽  
The Subject ◽  
Silylation Reaction ◽  
Flame Ionisation

The subject of this work was to characterize the catalytic course of the linseed oil silylation reaction with vinyltrimethoxysilane (VTMOS), carried out under elevated pressure and temperature conditions, and an explanation of the reasons for rapid gelation of the reaction product. To explain and describe the process, analytical methods were used, i.e., 1H and 13C NMR (nuclear magnetic resonance), GC-FID (gas chromatography coupled with flame ionisation detection), and GPC (gel permeation chromatography). Reaction products were monitored after 3, 6 and 12 h. The molar mass of the VTMOS-modified oil in only 3 h was comparable with the molar mass of the product obtained by conventional polymerisation. An increase in the reaction time resulted in further transformations resulting from the hydrolysis and condensation reactions taking place. In contrast to reactivity of soybean oil, the silanisation of linseed oil occurred much faster and without the need for cross-linking catalysts. The reason for the high reactivity of linseed oil to VTMOS and rapid gelation of the resulting product was primarily the amount of double bonds present in linseed oil and their high availability, in particular the double bond in the acid linolenic acid located at the C16 carbon.

Engineering Electronic Structure to Protect Phase Memory in Molecular Qubits by Minimising Orbital Angular Momentum

2018 ◽  
Author(s):  
Ana Maria Ariciu ◽  
David H. Woen ◽  
Daniel N. Huh ◽  
Lydia Nodaraki ◽  
Andreas Kostopoulos ◽  
...  
Keyword(s):  
Electron Spin ◽  
Quantum Coherence ◽  
Quantum Information Processing ◽  
Pulse Sequences ◽  
Grover Algorithm ◽  
Ligand Shell ◽  
Information Strategies ◽  
Spin Qubit ◽  
Molecular Spin ◽  
The Impact

Using electron spins within molecules for quantum information processing (QIP) was first proposed by Leuenberger and Loss (1), who showed how the Grover algorithm could be mapped onto a Mn12 cage (2). Since then several groups have examined two-level (S = ½) molecular spin systems as possible qubits (3-12). There has also been a report of the implementation of the Grover algorithm in a four-level molecular qudit (13). A major challenge is to protect the spin qubit from noise that causes loss of phase information; strategies to minimize the impact of noise on qubits can be categorized as corrective, reductive, or protective. Corrective approaches allow noise and correct for its impact on the qubit using advanced microwave pulse sequences (3). Reductive approaches reduce the noise by minimising the number of nearby nuclear spins (7-11), and increasing the rigidity of molecules to minimise the effect of vibrations (which can cause a fluctuating magnetic field via spin-orbit coupling) (9,11); this is essentially engineering the ligand shell surrounding the electron spin. A protective approach would seek to make the qubit less sensitive to noise: an example of the protective approach is the use of clock transitions to render spin states immune to magnetic fields at first order (12). Here we present a further protective method that would complement reductive and corrective approaches to enhancing quantum coherence in molecular qubits. The target is a molecular spin qubit with an effective 2S ground state: we achieve this with a family of divalent rare-earth molecules that have negligible magnetic anisotropy such that the isotropic nature of the electron spin renders the qubit markedly less sensitive to magnetic noise, allowing coherent spin manipulations even at room temperature. If combined with the other strategies, we believe this could lead to molecular qubits with substantial advantages over competing qubit proposals.<br>

scholarly journals Experimental study of the supercritical CO 2 diffusion coefficient in porous media under reservoir conditions

2019 ◽  
Vol 6 (6) ◽  
pp. 181902 ◽  
Author(s):  
Junchen Lv ◽  
Yuan Chi ◽  
Changzhong Zhao ◽  
Yi Zhang ◽  
Hailin Mu
Keyword(s):  
Porous Media ◽  
Diffusion Coefficient ◽  
Oil Recovery ◽  
Carbon Capture ◽  
Carbon Capture And Storage ◽  
Elevated Pressure ◽  
Experimental Results ◽  
Saturated Porous Media ◽  
Reservoir Conditions ◽  
The Impact

Reliable measurement of the CO 2 diffusion coefficient in consolidated oil-saturated porous media is critical for the design and performance of CO 2 -enhanced oil recovery (EOR) and carbon capture and storage (CCS) projects. A thorough experimental investigation of the supercritical CO 2 diffusion in n -decane-saturated Berea cores with permeabilities of 50 and 100 mD was conducted in this study at elevated pressure (10–25 MPa) and temperature (333.15–373.15 K), which simulated actual reservoir conditions. The supercritical CO 2 diffusion coefficients in the Berea cores were calculated by a model appropriate for diffusion in porous media based on Fick's Law. The results show that the supercritical CO 2 diffusion coefficient increases as the pressure, temperature and permeability increase. The supercritical CO 2 diffusion coefficient first increases slowly at 10 MPa and then grows significantly with increasing pressure. The impact of the pressure decreases at elevated temperature. The effect of permeability remains steady despite the temperature change during the experiments. The effect of gas state and porous media on the supercritical CO 2 diffusion coefficient was further discussed by comparing the results of this study with previous study. Based on the experimental results, an empirical correlation for supercritical CO 2 diffusion coefficient in n -decane-saturated porous media was developed. The experimental results contribute to the study of supercritical CO 2 diffusion in compact porous media.

scholarly journals The Impact of Pressure and Hydrocarbons on NOx Abatement over Cu- and Fe-Zeolites at Pre-Turbocharger Position

Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 336
Author(s):  
Deniz Zengel ◽  
Simon Barth ◽  
Maria Casapu ◽  
Jan-Dierk Grunwaldt
Keyword(s):  
Catalytic Reduction ◽  
Elevated Pressure ◽  
Systematic Investigation ◽  
Diesel Oxidation Catalyst ◽  
Zeolite Catalysts ◽  
Oxidation Catalyst ◽  
Pollutant Concentrations ◽  
Oxidation Of Hydrocarbons ◽  
Negative Effect ◽  
The Impact

Positioning the catalysts in front of the turbocharger has gained interest over recent years due to the earlier onset temperature and positive effect of elevated pressure. However, several challenges must be overcome, like presence of higher pollutant concentrations due to the absence or insufficient diesel oxidation catalyst volume at this location. In this context, our study reports a systematic investigation on the effect of pressure and various hydrocarbons during selective catalytic reduction (SCR) of NOx with NH3 over the zeolite-based catalysts Fe-ZSM-5 and Cu-SSZ-13. Using a high-pressure catalyst test bench, the catalytic activity of both zeolite catalysts was measured in the presence and absence of a variety of hydrocarbons under pressures and temperatures resembling the conditions upstream of the turbocharger. The results obtained showed that the hydrocarbons are incompletely converted over both catalysts, resulting in numerous byproducts. The emission of hydrogen cyanide seems to be particularly problematic. Although the increase in pressure was able to improve the oxidation of hydrocarbons and significantly reduce the formation of HCN, sufficiently low emissions could only be achieved at high temperatures. Regarding the NOx conversion, a boost in activity was obtained by increasing the pressure compared to atmospheric reaction conditions, which compensated the negative effect of hydrocarbons on the SCR activity.

scholarly journals Experimental and Computational Investigation of binary drop collisions under elevated pressure

2017 ◽  
Author(s):  
Jan Breitenbach ◽  
Louis Maximilian Reitter ◽  
Muyuan Liu ◽  
Kuan-Ling Huang ◽  
Dieter Bothe ◽  
...  
Keyword(s):  
Relative Velocity ◽  
Computational Study ◽  
Ambient Pressure ◽  
Experimental System ◽  
Elevated Pressure ◽  
Computational Investigation ◽  
Ambient Conditions ◽  
Influencing Parameters ◽  
Gas Layer ◽  
The Impact

Spray systems often operate under extreme ambient conditions like high pressure, which can have a significant influence on important spray phenomena. One of these phenomena is binary drop collisions. Such collisions, depending on the relative velocity and the impact parameter (eccentricity of the collision), can lead to drop bouncing, coalescence or breakup. This experimental and computational study is focused on the description of the phenomenon of drop bouncing, which is caused by a thin gas layer preventing the drops coalescence. To identify the main influencing parameters of this phenomenon, experiments on binary drop collisions are performed in a pressure chamber. This experimental system allows us to investigate the effect of an ambient pressure (namely the density and viscosity of the surrounding gas) on the bouncing/coalescence threshold.DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4758

Synthesis of Macromolecular Coupling Agent and its Effects on Polystyrene Composites

2014 ◽  
Vol 1053 ◽  
pp. 268-275
Author(s):  
Hong Wen Zhang ◽  
Shi Long Zhou ◽  
Yang Zhang ◽  
Yan Jiang ◽  
Qiang Yu
Keyword(s):  
Composite Materials ◽  
Gel Permeation Chromatography ◽  
Ultraviolet Spectrum ◽  
Butyl Methacrylate ◽  
Coupling Agents ◽  
Resonance Spectroscopy ◽  
H Nmr ◽  
Comprehensive Performance ◽  
Ft Ir ◽  
The Impact

Different molecular weight of block coupling agents with well-defined structures have been synthesized successfully by atom transfer radical polymerization (ATRP) from styrene (St), butyl methacrylate (BMA) and 3-methoxyacryloyl-propyltrimethoxyl silicon (KH-570) are as monomer. The structures and compositions of macromolecular coupling agents have been characterized by means of infrared spectrum (FT-IR), ultraviolet spectrum (UV), nuclear magnetic resonance spectroscopy (1H-NMR) and gel permeation chromatography (GPC). And their effects on the polystyrene/silica (PS/SiO2) composite materials have been studied. The results show that interface compatibility and mechanical properties of composite materials containing macromolecule coupling agents are improved significantly. The composite materials with block macromolecular coupling agents possess more excellent comprehensive performance. Furthermore, the impact strength increased by 110% when comparing with composite materials which are not modified by the coupling agents.

The Mechanochemistry of Synthetic Phosphate Oil under High Pressure

2010 ◽  
Vol 450 ◽  
pp. 185-188
Author(s):  
Bao Yu Song ◽  
Qing Xiang Yang ◽  
Yu Lin Qi ◽  
Dai Zhong Su
Keyword(s):  
Molecular Weight ◽  
High Pressure ◽  
Amorphous State ◽  
Gel Permeation Chromatography ◽  
Capillary Viscometer ◽  
Physical Factors ◽  
Strong Activity ◽  
Synthetic Oil ◽  
Relationship Of ◽  
The Impact

The pressure-viscosity relationships of phosphate synthetic oil and other two kinds of similar atmospheric viscosity synthetic oils were studied using ultra-high pressure capillary viscometer. The pressure-viscosity relationship of phosphate synthetic oil is much better than the other two kinds of synthetic oils. The impact of pressure on viscosity is not limited to purely physical factors. The pressure can cause a variety of chemical reactions in some cases. The investigation results of mechanochemistry of phosphate synthetic oil at high pressure reveal that the physical state of phosphate synthetic oil changed from liquid into glassy amorphous state under high pressure, and the color varied from transparent into milky white. The mechanochemistry of phosphate synthetic oil was analyzed using the infrared spectroscopy and gel permeation chromatography, and the results indicate that under high pressure, the oxidation reaction of phosphate synthetic oil occurred, and the molecular weight distribution changed with the increase of the low molecular weight region. The reason of the mechanochemistry phenomena was that phosphate synthetic oil molecular chain disconnects to inform great radical. The great radical has strong activity, and reacts with other free radicals acceptor (oxygen, etc).

scholarly journals Impact of the heat release distribution on high-frequency transverse thermoacoustic driving in premixed swirl flames

2016 ◽  
Vol 9 (3) ◽  
pp. 143-154 ◽  
Author(s):  
Michael Hertweck ◽  
Frederik M Berger ◽  
Tobias Hummel ◽  
Thomas Sattelmayer
Keyword(s):  
Heat Release ◽  
Combustion Chamber ◽  
High Frequency ◽  
Transfer Functions ◽  
Three Dimensional ◽  
Elevated Pressure ◽  
Rayleigh Index ◽  
The Stability ◽  
Stability Limits ◽  
The Impact

Self-excited, high-frequency first transversal thermoacoustic instabilities in a cylindrical combustion chamber equipped with a premixed swirl-stabilized flame are investigated. Phase-locked image analysis of the phenomena shows the displacement of the flame and a higher burning rate in the region of elevated pressure. The impact of diffuser angle and fuel composition on the stability limits and the flame position is investigated. The Rayleigh-Index is computed for a three-dimensional domain based on analytical flame transfer functions for experimentally obtained data of OH*-chemiluminescence as measure for the spatial heat release. Two models from different sources are applied, which describe the interaction between flame and acoustic locally. The axial dependence of the amplitude of the transversal mode is computed by a numerical model, which takes the temperature distribution inside the combustion chamber into account. The comparison of the Rayleigh-Index of different operation points shows a correlation with the stability limits for some, but not for all investigated configurations.

scholarly journals Effects of Gamma-Valerolactone Assisted Fractionation of Ball-Milled Pine Wood on Lignin Extraction and Its Characterization as Well as Its Corresponding Cellulose Digestion

2020 ◽  
Vol 10 (5) ◽  
pp. 1599
Author(s):  
Muhammad Ajaz Ahmed ◽  
Jae Hoon Lee ◽  
Arsalan A. Raja ◽  
Joon Weon Choi
Keyword(s):  
Quantum Coherence ◽  
Removal Rate ◽  
Value Added ◽  
Crystallinity Index ◽  
Gel Permeation Chromatography ◽  
Heteronuclear Single Quantum Coherence ◽  
Nmr Spectrum ◽  
Molecular Weights ◽  
Lignin Removal ◽  
Lignin Extraction

Gamma-valerolactone (GVL) was found to be an effective, sustainable alternative in the lignocellulose defragmentation for carbohydrate isolation and, more specifically, for lignin dissolution. In this study, it was adapted as a green pretreatment reagent for milled pinewood biomass. The pretreatment evaluation was performed for temperature (140–180 °C) and reaction time (2–4 h) using 80% aqueous GVL to obtain the highest enzymatic digestibility of 92% and highest lignin yield of 33%. Moreover, the results revealed a positive correlation (R2 = 0.82) between the lignin removal rate and the crystallinity index of the treated biomass. Moreover, under the aforementioned conditions, lignin with varying molecular weights (150–300) was obtained by derivatization followed by reductive cleavage (DFRC). 2D heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC-NMR) spectrum analysis and gel permeation chromatography (GPC) also revealed versatile lignin properties with relatively high β-O-4 linkages (23.8%–31.1%) as well as average molecular weights of 2847–4164 with a corresponding polydispersity of 2.54–2.96, indicating this lignin to be a heterogeneous feedstock for value-added applications of biomass. All this suggested that this gamma-valerolactone based pretreatment method, which is distinctively advantageous in terms of its effectiveness and sustainability, can indeed be a competitive option for lignocellulosic biorefineries.

Numerical assessment of ozone addition potential in direct injection compression ignition engines

2020 ◽  
pp. 146808742097355
Author(s):  
Vincent Giuffrida ◽  
Michele Bardi ◽  
Mickael Matrat ◽  
Anthony Robert ◽  
Guillaume Pilla
Keyword(s):  
Cfd Simulation ◽  
Fuel Injection ◽  
Direct Injection ◽  
High Reactivity ◽  
Experimental Results ◽  
Injection Timing ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Compression Stroke ◽  
The Impact

This paper aims at taking into account the chemistry of O3 in a 3D CFD simulation of compression ignition engine with Diesel type combustion for low load operating points. The methodology developed in this work includes 0D homogeneous reactors simulations, 3D RANS simulations and validation regarding experimental results. The 0D simulations were needed to take into account O3 reactions during the compression stroke because of the high reactivity of O3 with NO and dissociation at high temperature. The values found in these simulations were used as an input in the 3D model to match the correct O3 concentration at fuel injection timing. The 3D simulations were performed using CONVERGETM with a RANS approach. Simulations reproduce the compression/expansion stroke after the intake valve closure to focus on the impact of O3 on the fuel auto ignition. The comparison between numerical and experimental results demonstrates that the proposed methodology is able to capture correctly the impact of O3 addition on ignition delay and on heat release. Moreover, the analysis of the data enables to better understand the fundamental processes driving O3 impact in a CI engine. In particular, using 0D simulations, the plateau effect observed experimentally when increasing O3 concentration is attributed to O3 thermal decomposition and reaction with NO during the compression stroke. Also, 3D CFD results showed that O3 impact is observed mainly during LTHR phase and does not affect the topology and the propagation of the flame inside the combustion chamber.

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