Changes in the cell wall volume of a number of wood species due to reaction with acetic anhydride

Holzforschung ◽  
2007 ◽  
Vol 61 (2) ◽  
pp. 138-142 ◽  
Author(s):  
Jin H. Kwon ◽  
Callum A.S. Hill ◽  
Graham A. Ormondroyd ◽  
Siti Karim
Keyword(s):  
Cell Wall ◽  
Acetic Anhydride ◽  
Molar Volume ◽  
Volume Change ◽  
Wood Species ◽  
Korean Pine ◽  
Volume Changes ◽  
Weight Percentage ◽  
Acetyl Group ◽  
Helium Pycnometry

Abstract A number of softwoods and hardwoods (beech, rubberwood, Corsican pine, Korean pine) were reacted with acetic anhydride to a variety of weight percentage gain (WPG) values and the volume change due to reaction was determined both by measurement of the external dimensions and by helium pycnometry. The volume change due to modification determined by helium pycnometry was found to be equal to that calculated, except for Corsican pine. The volume change as determined by the external dimensions was not a reliable method for determining cell-wall volume changes. The molar volume of the acetyl group in the cell wall was calculated over a range of WPG values, with volumes ranging from approximately 32 to 42 cm3 mol-1, depending on the wood species studied. The differences in acetyl molar volume observed between most wood species were significant.

Dimensional changes in Corsican pine (Pinus nigra Arnold) modified with acetic anhydride measured using a helium pycnometer

Holzforschung ◽  
2004 ◽  
Vol 58 (5) ◽  
pp. 544-547 ◽  
Author(s):  
Callum A.S. Hill ◽  
Graham A. Ormondroyd
Keyword(s):  
Cell Wall ◽  
Acetic Anhydride ◽  
Linear Relationship ◽  
Volume Change ◽  
Pinus Nigra ◽  
Weight Percentage ◽  
Dimensional Changes ◽  
Percentage Volume ◽  
The Difference ◽  
Helium Pycnometry

Abstract Helium pycnometry was used to determine the changes in volume of wood samples of Corsican pine following modification with acetic anhydride. Results were compared with changes in volume determined from external dimensions only. Percentage change in volume, as determined from external dimensions of the sample, showed a non-linear relationship with weight percentage gain as a result of acetylation; whereas percentage volume change determined by helium pycnometry showed a linear relationship. The difference in volume as determined by the two methods is explained by considering volume change of the lumens as level of cell wall substitution increases. Results obtained in this study show that volume increases due to chemical modification, when determined by measurement of external dimensions, should not be used to evaluate changes in cell wall volume.

Acetyl Group Distribution in Acetylated Wood Investigated by Microautoradiography

Holzforschung ◽  
2001 ◽  
Vol 55 (3) ◽  
pp. 270-275 ◽  
Author(s):  
Marie Rosenqvist
Keyword(s):  
Cell Wall ◽  
Weight Gain ◽  
Acetic Anhydride ◽  
Wood Cell Wall ◽  
Environmental Scanning Electron Microscopy ◽  
Environmental Scanning ◽  
Accurate Information ◽  
Concentration Gradients ◽  
Good Opportunity ◽  
Acetyl Group

Summary Sapwood of Scots pine (Pinus silvestris L.) was acetylated with 14C- and 3H-labelled acetic anhydride. The distribution of acetyl groups was investigated with microautoradiography and microautoradiographs were evaluated with ESEM, Environmental Scanning Electron Microscopy. The investigation showed that the impregnation of wood with radioisotope-labelled substances provides a good opportunity to investigate the location of substances covalently bonded to the wood material. Introduced 14C-labelled acetyl groups show an even distribution in the wood cell wall, with no discernible concentration gradients at acetylation levels of about 5, 15 and 20% weight gain. 3H-labelled acetyl groups show an even distribution in the wood cell wall at 15 and 20% weight gain, with no discernible concentration gradients. At the 5% weight gain level, however, an uneven distribution of 3H-labelled acetyl groups over the cell wall is observed. Nevertheless, the unevenness is random and no concentration gradient is discernible at this level. 3H with a relatively high resolution, 0.5–1 μm, compared to 14C with a resolution of 2–5 μm, gives more accurate information about where exactly the acetyl groups are situated in the wood cell wall. Acetic anhydride was evenly distributed when a full impregnation procedure was used. The chemical and physical properties of acetic anhydride allow a uniform penetration into the pine cell wall and a complete acetylation takes place when the specimens are heated.

The apparent molar volumes of aqueous ammonia, ammonium chloride, aniline and anilinium chloride at 25°C and the volume changes on ionization

1975 ◽  
Vol 28 (10) ◽  
pp. 2109 ◽  
Author(s):  
RH Stokes
Keyword(s):  
Molar Volume ◽  
Ammonium Chloride ◽  
Volume Change ◽  
Apparent Molar Volume ◽  
Infinite Dilution ◽  
Aqueous Ammonia ◽  
Apparent Molar Volumes ◽  
Volume Changes ◽  
Molar Volumes ◽  
Standard States

The apparent molar volumes of aqueous ammonia, ammonium chloride, aniline and anilinium chloride are measured up to 2 mol l-1 at 25�C by a combination of pyknometric and dilatometric methods. The apparent molar volume f�V of undissociated ammonia at infinite dilution is found to be 24.85�0.02 cm3 mol-1, and that of NH4Cl is 35.71�0.02 cm3 mol-1. The volume change on ionization for the standard states ΔV� is -29.07�0.04 cm3 mol-1. For aniline the values are: f�V(PhNH2) 89.30, f�V(PhNH3Cl) 102.74 and ΔV� -26.49�0.05 cm3 mol-1.

Volume Change Associated to Carbon Partitioning from Martensite to Austenite

2012 ◽  
Vol 706-709 ◽  
pp. 2290-2295 ◽  
Author(s):  
M. J. Santofimia ◽  
Lie Zhao ◽  
Jilt Sietsma
Keyword(s):  
Volume Change ◽  
Chemical Potential ◽  
Theoretical Models ◽  
Carbon Partitioning ◽  
Volume Changes ◽  
Measured Volume

Annealing of martensite/austenite microstructures leads to the partitioning of carbon from martensite to austenite until the chemical potential of carbon equilibrates in both phases. This work calculates the volume change associated with this phenomenon using theoretical models for the carbon partitioning from martensite to austenite. Calculations are compared with experimentally determined volume changes. This comparison reveals that in the case of steels with higher contents of austenite-stabilizing elements, reported volume changes are satisfactory predicted assuming a low mobilily martensite/austenite interface. In the case of a steel with lower additions of austenite-stabilizing elements, experimentally measured expansions are considerably larger than predicted ones. The large measured volume expansions probably reflect the decomposition of the austenite.

Cell Wall Pore Structures of Bamboo as Relation to Species and Tissue Types

2021 ◽  
Author(s):  
Mengdan Cao ◽  
Wenting Ren ◽  
Jiawei Zhu ◽  
Hankun Wang ◽  
Juan Guo ◽  
...  
Keyword(s):  
Cell Wall ◽  
Wood Species ◽  
Distinct Species ◽  
Bamboo Species ◽  
Compact Structure ◽  
Pore Structures ◽  
Mesopore Structure ◽  
Parenchyma Cells ◽  
Bamboo Fibers ◽  
Cell Wall Porosity

Abstract Efficient convention of bamboo biomass into biofuel and biomaterials, as well as chemical treatment are both highly related to the porosity of cell wall. The present work characterizes the micropore and mesopore structure in cell walls of six different bamboo species and tissue types using CO2 and N2 adsorption. Two plantation wood species were also tested for comparison. Bamboo species normally showed lower cell wall porosity (2.64%-3.75%) than wood species (3.98%-5.06%), indicating a more compact structure for bamboo than wood. A distinct species dependence of cell wall pore structures and porosity was also observed. Furthermore, the cell wall pore structure and porosity are shown to be tissue-specific, as the parenchyma cells exhibit higher pore volume and porosity compared to bamboo fibers. The obtained results give new explanations on the known facts that both bamboo and bamboo fibers exhibit higher biomass recalcitrance as compared to wood and bamboo parenchyma cells, constructing the base of pretreatment optimization and subsequent processing for bamboo-derived biofuels and biomaterials.

A New Micro-Respirometer with Automatic Setting and Recording Apparatus

1950 ◽  
Vol 27 (3) ◽  
pp. 334-349
Author(s):  
PETER TUFT
Keyword(s):  
Volume Change ◽  
Constant Pressure ◽  
Volume Changes ◽  
Recording Apparatus

A new micro-respirometer is described, capable of measuring rates of volume change from 5 µl./hr. down to 0.01 µl./hr. to the nearest 0.001 µl. It is a constant-pressure nul-reading instrument and the actual volumes of gas absorbed or evolved are obtained from readings of the instrument by a simple multiplication. A device is described which sets the instrument automatically and records the volume changes at regular intervals.

Sequence, Salt, Charge, and the Stability of DNA at High Pressure

1996 ◽  
Author(s):  
Robert B. Macgregor Jr ◽  
John Q. Wu
Keyword(s):  
Molar Volume ◽  
Volume Change ◽  
Salt Concentration ◽  
Electrostatic Interactions ◽  
Proposed Model ◽  
Dna Strands ◽  
Positive Volume ◽  
Ion Radius ◽  
The Stability ◽  
Kinetics Of

The effect of pressure on the helix-coil transition temperature (Tm) is reported for the double-stranded polymers poly(dA)poly(dT), poly[d(A-T)], poly[d(l-C], and poly[d(G-C] and triple-stranded poly(dA)2poly(dT). The Tm increases as a function of pressure, implying a positive volume change for the transition and leading to the conclusion that the molar volume of the coil form is larger than the molar volume of the helix. From the change in Tm as a function of pressure, molar volume changes of the transition (ΔVt) are calculated using the Clapeyron equation and calorimetrically determined enthalpies. For the doublestranded polymers, ΔVt, increases in the order poly[d(l-C] < polyt[d(A-T)] < poly(dA)-poly(dT) < polylcl(G-C)]. The value of ΔVt, for the triple-stranded to single-stranded transition of poly(dA) 2poly(dT) is larger than that of poly[d(G-C)I. The magnitude of ΔVt increases with salt concentration in all cases studied; however, the change of ΔVt with salt concentration depends on the sequence of the DNA and the number of strands involved in the transition. In the model proposed to explain the results, the overall molar volume change of the transition is a function of a negative volume change arising from changes in the electrostatic interactions of the DNA strands, and a positive volume change due to unstacking the bases. The model predicted the direction of the change in the ΔVt for several experiments. The magnitude of AVJ increases with counter ion radius, thus for polyld(A-T)], ΔVt, increases in the series Na+ , K+, Cs+, The ΔVt also increases if the charge on the phosphodiester groups is removed. The kinetics of the formation of double-stranded (dA)19(dT)19 in 50 mM NaCI are slowed approximately 14-fold at 200 MPa relative to atmospheric pressure. The implied volume of activation of +37 ml mol−l in the direction of this change is also in agreement with the proposed model. The stability of double- and triple-stranded DNA helices in water around neutral pH depends on the base composition and sequence, as well as on the ionic strength of the solution. Each of these dependencies also defines how DNA interacts with water.

scholarly journals Comparison of the Decay Behavior of Two White-Rot Fungi in Relation to Wood Type and Exposure Conditions

2020 ◽  
Vol 8 (12) ◽  
pp. 1931
Author(s):  
Ehsan Bari ◽  
Geoffrey Daniel ◽  
Nural Yilgor ◽  
Jong Sik Kim ◽  
Mohammad Ali Tajick-Ghanbary ◽  
...  
Keyword(s):  
Cell Wall ◽  
Moisture Content ◽  
Wood Species ◽  
White Rot Fungi ◽  
White Rot ◽  
High Mass ◽  
Type I ◽  
Oak Wood ◽  
Mass Losses ◽  
Decay Behavior

Fungal wood decay strategies are influenced by several factors, such as wood species, moisture content, and temperature. This study aims to evaluate wood degradation characteristics of spruce, beech, and oak after exposure to the white-rot fungi Pleurotusostreatus and Trametesversicolor. Both fungi caused high mass losses in beech wood, while spruce and oak wood were more resistant to decay. The moisture content values of the decayed wood correlated with the mass losses for all three wood species and incubation periods. Combined microscopic and chemical studies indicated that the two fungi differed in their decay behavior. While T. versicolor produced a decay pattern (cell wall erosion) typical of white-rot fungi in all wood species, P. ostreatus caused cell wall erosion in spruce and beech and soft-rot type I (cavity formation) decay in oak wood. These observations suggest that P. ostreatus may have the capacity to produce a wider range of enzymes/radicals triggered by the chemical composition of wood cell walls and/or local compositional variability within the cell wall.

A DILATOMETRIC STUDY OF SOLID METHANOL-d

1956 ◽  
Vol 34 (9) ◽  
pp. 1243-1248 ◽  
Author(s):  
D. W. Davidson
Keyword(s):  
Melting Point ◽  
Molar Volume ◽  
The Other ◽  
Gradual Transition ◽  
Calorimetric Data ◽  
Volume Changes ◽  
First Order ◽  
Dilatometric Study

With isopentane as the dilatometric liquid, CH3OD was examined between 120 °K. and the melting point. There is evidence of two transitions within the solid: one, in the vicinity of 158 °K., appears to be a gradual transition, the other, at 163 °K., a first-order one. The corresponding molar volume changes are 0.04 and 0.43 ml. A further change of volume of 2.67 ml./mole occurs at the melting point. These results are compared with recent dilatometric results for CH3OH and discussed with reference to the available calorimetric data. The molar volume of CH3OD is slightly greater than that of CH3OH in both liquid and solid forms.

Regioselective N-Acetylation of 4-(2-Hydroxyphenyl)-2-phenyl-2,3- dihydro-1H-1,5-benzodiazepine Using Protection by an Intramolecular Hydrogen Bond

2009 ◽  
Vol 64 (8) ◽  
pp. 969-972 ◽  
Author(s):  
Carlos A. Escobar ◽  
Jorge Orellana-Vera ◽  
Andrés Vega ◽  
Dieter Sicker ◽  
Joachim Sieler
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Acetic Anhydride ◽  
Ambient Temperature ◽  
Intramolecular Hydrogen Bond ◽  
Structure Analysis ◽  
Crystal Structure Analysis ◽  
Hydroxyl Groups ◽  
Acetyl Group ◽  
Intramolecular Hydrogen

Since the amino and the hydroxyl groups of 4-(2-hydroxyphenyl)-2-phenyl-2,3-dihydro-1H-1,5- benzodiazepine can both act as nucleophiles, the introduction of both an N-acetyl and an O-acetyl group is expected when the compound is allowed to react with an excess of an electrophile such as acetic anhydride. An intramolecular hydrogen bond between OH and N-5 of the benzodiazepine has been used to obtain differentiation between the two possible sites of acetylation. Thus, this feature offers a preparatively utilizable protecting effect for the OH group and allows for a regioselective N-acetylation at ambient temperature. Both mono- and diacetylated compounds were prepared and characterized by crystal structure analysis

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