AN INVESTIGATION OF THE CHLORINATION OF SPRUCE WOOD AND OF THE RESULTING CHLOROLIGNIN

1937 ◽  
Vol 15b (7) ◽  
pp. 279-294 ◽  
Author(s):  
G. V. Jansen ◽  
J. W. Bain
Keyword(s):  
Methyl Alcohol ◽  
Ring Structure ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Hydrogen Atoms ◽  
Chlorine Atoms ◽  
Spruce Wood ◽  
Simple Substitution ◽  
Homogeneous Fraction ◽  
Acid Reduction

Spruce sawdust was chlorinated under various conditions in an attempt to procure a homogeneous lignin chloride. Success finally attended the use of methyl alcohol as a medium for chlorination. The lignin chloride, which was dissolved by the alcohol during the chlorination and subsequently precipitated by the addition of water, was cream white in color, and analysis showed it to be an alcohol lignin.A homogeneous fraction (No. 2) was obtained from the re-chlorinated product, and it proved to be a chlorinated analogue of Hibbert's monomethylated methyl alcohol lignin, the formulas of the two products being C42H22O6Cl13(OH)2(OCH3)7, and C42H32O6(OH)3(OCH3)7. The molecular weight and the presence of the two hydroxyl groups were confirmed by acetylation, when 2.0 acetyl groups entered the molecule. Eleven of the chlorine atoms in Fraction 2 have evidently replaced ten hydrogen atoms and one hydroxyl group by simple substitution in methyl alcohol lignin, leaving two chlorine atoms which have apparently entered to saturate a double bond. Seven of these chlorine atoms have been shown to be readily removable either by an alkali or by acid reduction. The other six, because of their stable union with the molecule, are surmised to be joined to an aromatic nucleus or at least to some type of ring structure. The product has been shown to react stoichiometrically within limits as narrow as could be expected for such a large molecule.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: XVI. PHENOL LIGNIN FROM SPRUCE WOOD, FROM FREUDENBERG SPRUCE LIGNIN AND WILLSTÄTTER SPRUCE LIGNIN

1935 ◽  
Vol 13b (2) ◽  
pp. 61-77 ◽  
Author(s):  
Irene Koerber Buckland ◽  
Fritz Brauns ◽  
Harold Hibbert
Keyword(s):  
Condensation Product ◽  
Analytical Data ◽  
Insoluble Fraction ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Condensation Products ◽  
Building Unit ◽  
Spruce Wood ◽  
Analytical Results ◽  
The Difference

The condensation of lignin with phenol by treatment of spruce wood meal with this solvent, using hydrogen chloride as catalyst, yields two chemically different phenol lignins, namely, an ether-insoluble and an ether-dioxane–soluble phenol lignin, in a ratio of approximately 3 to 1. Duplicate preparations gave the same yields of these two fractions, analyses of which gave concordant results, indicating homogeneity and constancy of composition.The analytical results of the ether-insoluble phenol lignin, and of its methylated and acetylated derivatives, can be interpreted on the basis of the Brauns–Hibbert formula for the "native" lignin unit. It is found, in this way, that the ether-insoluble phenol lignin contains three new free phenolic hydroxyl groups capable of methylation with diazomethane, while one phenol group has reacted with one hydroxyl group in the lignin unit with formation of a phenyl-oxygen ether linkage.The analytical results of the ether-dioxane–soluble phenol lignin indicate that a much larger quantity of phenol has condensed with the "native" lignin building unit than in the case of the ether-insoluble fraction. The exact number of phenol molecules reacting to form this condensation product has not been determined experimentally although calculations based on analytical data point to a number as large as 15 or 21.The phenol condensation products were obtained from Freudenberg and Willstätter lignins in nearly quantitative yield and found to differ from the directly extracted phenol lignin in that neither of them could be resolved into two fractions, thus indicating that some change had taken place in the native lignin during the isolation process. The Brauns-Hibbert formula can also be applied to interpret the experimental data in both cases. These lignins appear to contain the same fundamental building unit as the ether-insoluble phenol lignin fraction isolated directly from spruce wood, with the difference that the former probably have one additional hydroxyl group capable of acetylation and diazomethane-methylation.The correlation found to exist in the present investigation between the phenol condensation products from native spruce lignin, isolated Freudenberg lignin and Willstätter lignin is regarded as providing definite experimental evidence indicating the presence of a chemical unit common to various lignins. The phenol condensation products, it is considered, may serve as valuable reference compounds for proving the identity of lignins obtained from different sources and by use of different chemical reagents.

scholarly journals SIGNIFICANCE OF THE HYDROXYL GROUPS OF STEROIDS IN PROMOTING GROWTH

1954 ◽  
Vol 100 (3) ◽  
pp. 241-246 ◽  
Author(s):  
Charles Huggins ◽  
Elwood V. Jensen
Keyword(s):  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Critical Importance ◽  
Hydrogen Atoms ◽  
Albino Rat ◽  
Ketone Group ◽  
Related Compounds

The presence of a 17ß-hydroxyl group endows the simple androstane molecule with the ability to produce growth of the uterus, vagina, and prostate of the female hypophysectomized albino rat. It appears that hydrogen atoms at position 17 are of critical importance since related compounds with a ketone group at this site are inactive. Monofunctional steroids with a hydroxyl or a ketone group at position 3 likewise are devoid of activity. If a phenolic A-ring is present in monofunctional steroids the 17ß-hydroxyl group is not obligatory for growth. Proliferation of the uterus and vagina were found to follow the administration of 17-desoxyestradiol.

Activation of the Hydrogen-Terminated Diamond [100] by Hydrogen Atoms and Hydroxyl Groups

2020 ◽  
Vol 996 ◽  
pp. 151-156
Author(s):  
Xiao Gang Jian ◽  
Ji Bo Hu ◽  
Xin Huang ◽  
Pei Kang Yang ◽  
Jun Peng Wang
Keyword(s):  
Hydrogen Atom ◽  
Low Temperature ◽  
Density Functional ◽  
Diamond Surface ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Hydrogen Atoms ◽  
Activation Rate ◽  
Limiting Stage ◽  
Rate Limiting

The process of producing active vacancies on a hydrogen-terminated diamond surface is the most important rate-limiting stage in CH4/H2 and CH4/H2/CO2 atmospheres. Hydrogen atom and the hydroxyl group can bone to the hydrogen atom on the diamond surface and create an active vacancy. Density functional theory (DFT) was used to study the extraction reaction by two reactants both hydrogen atom and the hydroxyl group. The result indicated that the hydroxyl group could reduce the energy required for diamond surface activation. What is more, the activation rate of the surface by the hydroxyl group was livelier at low temperature, while the activation rate of the hydrogen atom predicts on the contrary. The scanning electron microscope (SEM) and Raman spectra demonstrated that the introduction of CO2 in the CH4/H2 atmosphere could reduce the deposition temperature and raise the deposition rate at low temperature.

Conformation of the esters of steroid hydroxyl groups by infrared spectroscopy

1969 ◽  
Vol 47 (9) ◽  
pp. 1601-1603 ◽  
Author(s):  
C. R. Narayanan ◽  
M. R. Sarma ◽  
T. K. K. Srinivasan ◽  
M. S. Wadia
Keyword(s):  
Hydrogen Bonding ◽  
Infrared Spectroscopy ◽  
Carbonyl Group ◽  
Hydroxyl Group ◽  
Spectral Studies ◽  
Hydroxyl Groups ◽  
Hydrogen Atoms ◽  
Infrared Spectral

Infrared spectral studies show that the carbonyl group of the esters of steroid hydroxyl groups are stabilized near the adjacent alkyl hydrogen atoms; this energy of stabilization appears to be more than that of hydrogen bonding between the carbonyl and a nearby hydroxyl group.

Towards clathrates. 2. The frozen states of hydration of tert-butanol

2018 ◽  
Vol 233 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Lukasz Dobrzycki
Keyword(s):  
Single Crystal ◽  
Crystalline Phase ◽  
Ambient Pressure ◽  
Water System ◽  
Hydroxyl Group ◽  
Molar Ratio ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Hydrogen Atoms ◽  
Ir Laser

AbstractA new crystal structure oftert-butanol and water crystallizing as the decahydrate is reported. The crystallization of the mixture in the desired molar ratio was performed in a capillary placed directly on a goniometer of a single crystal diffractometer at 200 K and ambient pressure using focused IR laser radiation. The crystals were grown while the melting zone formed by the IR laser was moved along the capillary. Usually the crystallization process should be long enough (hours) in order to obtain a good quality single crystal. However, in the case oftert-butanol decahydrate, such a long process led to separation of the ice and alcohol. Only fast crystallization taking tens of seconds allowed crystallization of the desired crystalline phase. In the decahydratetert-butanol molecules are located in channels formed by water molecules. Hydroxyl groups are anchored to the water framework via hydrogen bonds. All water molecules in the structure have hydrogen atoms disordered equally over two sites; the hydroxyl group is likewise disordered. This effect is observed at both, 200 K and 100 K. Raman spectra recorded for the crystalline phase suggest dynamic disorder at higher temperature, converting to static at lowerT. The decahydrate oftert-butanol, together with already known itsdi- andhepta-hydrates, display similar features to those observed for series oftert-butylamine hydrates. The latter structures behave as frozen steps of amine hydration observed as crystal structures leading, at maximum dilution, to hexagonal ice. Hydrates oftert-butanol nicely follow this tendency completing the relationship found for thetert-butylamine: water system.

scholarly journals Water in the Alluaudite Type-Compounds: Synthesis, Crystal Structure and Magnetic Properties of Co3(AsO4)0.5+x(HAsO4)2−x(H2AsO4)0.5+x[(H,□)0.5(H2O,H3O)0.5]2x+

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1372
Author(s):  
Tamara Đorđević ◽  
Ljiljana Karanović ◽  
Marko Jagodič ◽  
Zvonko Jagličić
Keyword(s):  
Crystal Structure ◽  
Tetrahedral Site ◽  
Hydroxyl Group ◽  
Dimensional Structure ◽  
Site Symmetry ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
Hydrogen Atoms ◽  
Hydrothermal Conditions ◽  
Cobalt Ions

In this study, a new cobalt arsenate belonging to the alluaudite supergroup compounds with the general formula of Co3(AsO4)0.5+x(HAsO4)2−x(H2AsO4)0.5+x[(H,□)0.5(H2O,H3O)0.5]2x+ (denoted as CoAsAllu) was synthesized under hydrothermal conditions. Its crystal structure was determined by a room-temperature single-crystal X-ray diffraction analysis: space group C2/c, a = 11.6978(8), b = 12.5713(7), c = 6.7705(5) Å, β = 113.255(5)°, V = 914.76(11) Å3, Z = 2 for As6H8Co6O25. It represents a new member of alluaudite-like protonated arsenates and the first alluaudite-like phase showing both protonation of the tetrahedral site and presence of the H2O molecules in the channels. In the asymmetric unit of CoAsAllu, one of the two Co, one of the two As and one of the seven O atoms lie at 4e special positions (site symmetry 2). The crystal structure consists of the infinite edge-shared CoO6 octahedra chains, running parallel to the [101¯] direction. The curved chains are interconnected by [(As1O4)0.5(H2As1O4)0.5]2− and [HAs2O4]2− tetrahedra forming a heteropolyhedral 3D open framework with two types of parallel channels. Both channels run along the c-axis and are located at the positions (1/2, 0, z) and (0, 0, z), respectively. The H2 and H4 hydrogen atoms of O2H2 and O4H4 hydroxyl groups are situated in channel 1, while the uncoordinated water molecule H2O7 at half-occupied 4e special positions and hydrogen atoms of O6H6 hydroxyl group were found in channel 2. The results of the magnetic investigations confirm the quasi one-dimensional structure of divalent cobalt ions. They are antiferromagnetically coupled with the intrachain interaction parameter of J ≈ −8 cm−1 and interchain parameter of J’ ≈ −2 cm−1 that become effective below the Néel temperature of 3.4 K.

scholarly journals Interaction of Refractory Dibenzothiophenes and Polymerizable Structures

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Jose L. Rivera ◽  
Pedro Navarro-Santos ◽  
Roberto Guerra-Gonzalez ◽  
Enrique Lima
Keyword(s):  
Hydrogen Bonds ◽  
First Principles ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
First Principles Calculations ◽  
Amino Groups ◽  
Hydrogen Atoms ◽  
Methylene Groups ◽  
Monomeric Structure ◽  
Additional Hydrogen

We carried out first principles calculations to show that polymerizable structures containing hydroxyl (alcoholic chain) and amino groups are suitable to form stable complexes with dibenzothiophene (DBT) and its alkyl derivates. These sulfur pollutants are very difficult to eliminate through traditional catalytic processes. Spontaneous and exothermic interactions at 0 K primarily occur through the formation of stable complexes of organosulfur molecules with monomeric structures by hydrogen bonds. The bonds are formed between the sulfur atom and the hydrogen of the hydroxyl group; additional hydrogen bonds are formed between the hydrogen atoms of the organosulfur molecule and the nitrogen atoms of the monomers. We vary the number of methylene groups in the alcoholic chain containing the hydroxyl group of the monomer and find that the monomeric structure with four methylene groups has the best selectivity towards the interaction with the methyl derivates with reference to the interaction with DBT. Even this study does not consider solvent and competitive adsorption effects; our results show that monomeric structures containing amino and hydroxyl groups can be used to develop adsorbents to eliminate organosulfur pollutants from oil and its derivates.

The Influence of Hydrogen atoms on the Performance of Radial Distribution Function Based Descriptors in the Chemoinformatic Studies of HIV-1 Prote-ase Complexes with Inhibitors.

2020 ◽  
Vol 17 ◽  
Author(s):  
Jurica Novak ◽  
Maria A. Grishina ◽  
Vladimir A. Potemkin
Keyword(s):  
Distribution Function ◽  
Radial Distribution Function ◽  
Radial Distribution ◽  
Current Model ◽  
Direct Interaction ◽  
Hydroxyl Group ◽  
Linear Regression Method ◽  
Hydrogen Atoms ◽  
Protease Enzyme ◽  
Hiv 1

: In this letter the newly introduced approach based on the radial distribution function (RDF) weighted by the number of va-lence shell electrons is applied for a series of HIV-1 protease enzyme and its complexes with inhibitors to evaluate the influ-ence of hydrogen atoms on the performance of the model. The multiple linear regression method was used for the selection of the relevant descriptors. Two groups of residues having dominant contribution to the RDF descriptor are identified as relevant for the inhibition. In the first group are residues like Arg8, Asp25, Thr26, Gly27 and Asp29, which establish direct interaction with the inhibitor, while the second group consists of the amino acids at the interface of the two homodimer sub-units or with the solvent. The crucial motif pointed out by our approach as the most important for inhibition of the enzyme’s activity and present in all inhibitors is hydroxyl group that establish hydrogen bond with Asp25 side chain. Additionally, the comparison to the model without hydrogen showed that both models are of similar quality, but the downside of the current model is the need for the determination of residues’ protonation states.

scholarly journals Reactivity of Aliphatic and Phenolic Hydroxyl Groups in Kraft Lignin towards 4,4′ MDI

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2131
Author(s):  
Leonardo Dalseno Antonino ◽  
Júlia Rocha Gouveia ◽  
Rogério Ramos de Sousa Júnior ◽  
Guilherme Elias Saltarelli Garcia ◽  
Luara Carneiro Gobbo ◽  
...  
Keyword(s):  
Experimental Work ◽  
Chemical Structure ◽  
31P Nmr ◽  
Kraft Lignin ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Diphenylmethane Diisocyanate ◽  
Complex Chemical ◽  
Heterogeneous Reactivity ◽  
Phenolic Hydroxyl Groups

Several efforts have been dedicated to the development of lignin-based polyurethanes (PU) in recent years. The low and heterogeneous reactivity of lignin hydroxyl groups towards diisocyanates, arising from their highly complex chemical structure, limits the application of this biopolymer in PU synthesis. Besides the well-known differences in the reactivity of aliphatic and aromatic hydroxyl groups, experimental work in which the reactivity of both types of hydroxyl, especially the aromatic ones present in syringyl (S-unit), guaiacyl (G-unit), and p-hydroxyphenyl (H-unit) building units are considered and compared, is still lacking in the literature. In this work, the hydroxyl reactivity of two kraft lignin grades towards 4,4′-diphenylmethane diisocyanate (MDI) was investigated. 31P NMR allowed the monitoring of the reactivity of each hydroxyl group in the lignin structure. FTIR spectra revealed the evolution of peaks related to hydroxyl consumption and urethane formation. These results might support new PU developments, including the use of unmodified lignin and the synthesis of MDI-functionalized biopolymers or prepolymers.

scholarly journals Enhancement of Antioxidant and Hydrophobic Properties of Alginate via Aromatic Derivatization: Preparation, Characterization, and Evaluation

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2575
Author(s):  
Smaher M. Elbayomi ◽  
Haili Wang ◽  
Tamer M. Tamer ◽  
Yezi You
Keyword(s):  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Benzoyl Group ◽  
Antioxidant Evaluation ◽  
Thermo Stability

The preparation of bioactive polymeric molecules requires the attention of scientists as it has a potential function in biomedical applications. In the current study, functional substitution of alginate with a benzoyl group was prepared via coupling its hydroxyl group with benzoyl chloride. Fourier transform infrared spectroscopy indicated the characteristic peaks of aromatic C=C in alginate derivative at 1431 cm−1. HNMR analysis demonstrated the aromatic protons at 7.5 ppm assigned to benzoyl groups attached to alginate hydroxyl groups. Wetting analysis showed a decrease in hydrophilicity in the new alginate derivative. Differential scanning calorimetry and thermal gravimetric analysis showed that the designed aromatic alginate derivative demonstrated higher thermo-stability than alginates. The aromatic alginate derivative displayed high anti-inflammatory properties compared to alginate. Finally, the in vitro antioxidant evaluation of the aromatic alginate derivative showed a significant increase in free radical scavenging activity compared to neat alginate against DPPH (2,2-diphenyll-picrylhydrazyl) and ABTS free radicals. The obtained results proposed that the new alginate derivative could be employed for gene and drug delivery applications.

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