STUDIES ON LIGNIN AND RELATED COMPOUNDS: XXI. INSOLUBLE METHANOL LIGNIN

1936 ◽  
Vol 14b (2) ◽  
pp. 55-64
Author(s):  
Herbert W. Mackinney ◽  
Harold Hibbert
Keyword(s):  
Hydrogen Chloride ◽  
Dimethyl Sulphate ◽  
Close Relation ◽  
Subsequent Treatment ◽  
Hydroxyl Group ◽  
Soluble Form ◽  
Spruce Wood ◽  
Insoluble Form ◽  
New Evidence ◽  
Related Compounds

When spruce wood meal is extracted with anhydrous methyl alcoholic hydrogen chloride, about 30% of the lignin can be removed in soluble form. The insoluble lignin in the residual wood can be isolated as a fully methylated derivative by a prior complete methylation with dimethyl sulphate followed by hydrolysis with methyl alcoholic hydrogen chloride. The fully methylated insoluble methanol lignin is insoluble in organic solvents.Demethylation experiments followed by subsequent treatment with methylating and acetylating agents, alone or combined, have established a very close relation between the insoluble and the soluble form. The formation of the insoluble form from the native lignin is accompanied by loss of one hydroxyl group as indicated in the two formulas: soluble methanol lignin, C42H32O6(OCH3)6(OH)4, and insoluble methanol lignin (fully methylated), C42H32O6OCH3)9. The new evidence obtained indicates that of the five methoxyl groups present in the original native lignin, at least three are phenolic or enolic in character.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: XII. METHANOL LIGNIN

1935 ◽  
Vol 13b (1) ◽  
pp. 28-34 ◽  
Author(s):  
Fritz Brauns ◽  
Harold Hibbert
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Methyl Alcohol ◽  
Empirical Formula ◽  
Dimethyl Sulphate ◽  
Compound A ◽  
Wood Meal ◽  
Building Unit ◽  
Spruce Wood ◽  
Related Compounds

Methanol lignin was prepared by extracting spruce wood meal with absolute methyl alcohol, using hydrochloric acid as catalyst. In five small, bomb-tube experiments, methanol lignin preparations having the same methoxyl content (about 21.6%) were obtained, the product in each case being apparently homogeneous. The methanol lignin was acetylated, partially methylated by treatment with diazomethane, and fully methylated with dimethyl sulphate and sodium hydroxide. From the elementary analyses and the ratio of methoxyl in the original methanol lignin to that in the diazomethane-methylated compound a formula for the smallest building unit of the methanol lignin and for the native lignin can be derived. The latter is represented by the empirical formula C47H52O16, or, expanded, C42H32O6(OCH3)5(OH)5.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: XIX. ALKALI LIGNIN

1935 ◽  
Vol 13b (2) ◽  
pp. 103-113 ◽  
Author(s):  
H. Borden Marshall ◽  
Fritz Brauns ◽  
Harold Hibbert
Keyword(s):  
Sodium Hydroxide ◽  
Hydrogen Chloride ◽  
Dimethyl Sulphate ◽  
Analytical Data ◽  
Hydroxyl Groups ◽  
Empirical Formulas ◽  
Alkali Lignin ◽  
Phenol Derivatives ◽  
Related Compounds ◽  
Partially Methylated

Alkali lignin was prepared by the method of Mehta (6). It was separated into two fractions, termed Alkali Lignin A, insoluble in dioxane-ether, and Alkali Lignin B, soluble in dioxane-ether. Both compounds were acetylated, partially methylated with diazomethane and fully methylated using dimethyl sulphate and sodium hydroxide. Treatment of both alkali lignins with phenol, using hydrogen chloride as catalyst, yielded phenol condensation products. Phenol Alkali Lignin A was acetylated, partially methylated with diazomethane and completely methylated with dimethyl sulphate and sodium hydroxide. It was found that one mole of Alkali Lignin A reacted with two moles of phenol. Alkali Lignin B yielded two phenol derivatives, an ether-insoluble and an ether-soluble product, which differ in the number of attached phenol groups. p-Bromphenol and o-bromphenol were also shown to react with Alkali Lignin A giving lignin derivatives having identical methoxyl and bromine content. On treatment of Alkali Lignin A with anhydrous methyl alcohol and hydrogen chloride a product with a higher methoxyl content was obtained, indicating the presence of hydroxyl groups capable of methylation with this reagent. From the analytical data of the different compounds some theoretical conclusions are drawn, and empirical formulas derived.

scholarly journals Characterization of an Insoluble and Soluble Form of Melanin Produced by Streptomyces cavourensis SV 21, a Sea Cucumber Associated Bacterium

Marine Drugs ◽  
2022 ◽  
Vol 20 (1) ◽  
pp. 54
Author(s):  
Joko Tri Wibowo ◽  
Matthias Y. Kellermann ◽  
Lars-Erik Petersen ◽  
Yustian R. Alfiansah ◽  
Colleen Lattyak ◽  
...  
Keyword(s):  
Biological Properties ◽  
Water Soluble ◽  
Soluble Form ◽  
Wide Range ◽  
Biological Form ◽  
Insoluble Form ◽  
New Perspective ◽  
Living Organisms ◽  
Purification Protocol

Melanin is a widely distributed and striking dark-colored pigment produced by countless living organisms. Although a wide range of bioactivities have been recognized, there are still major constraints in using melanin for biotechnological applications such as its fragmentary known chemical structure and its insolubility in inorganic and organic solvents. In this study, a bacterial culture of Streptomyces cavourensis SV 21 produced two distinct forms of melanin: (1) a particulate, insoluble form as well as (2) a rarely observed water-soluble form. The here presented novel, acid-free purification protocol of purified particulate melanin (PPM) and purified dissolved melanin (PDM) represents the basis for an in-depth comparison of their physicochemical and biological properties, which were compared to the traditional acid-based precipitation of melanin (AM) and to a synthetic melanin standard (SM). Our data show that the differences in solubility between PDM and PPM in aqueous solutions may be a result of different adjoining cation species, since the soluble PDM polymer is largely composed of Mg2+ ions and the insoluble PPM is dominated by Ca2+ ions. Furthermore, AM shared most properties with SM, which is likely attributed to a similar, acid-based production protocol. The here presented gentler approach of purifying melanin facilitates a new perspective of an intact form of soluble and insoluble melanin that is less chemical altered and thus closer to its original biological form.

Computational Mechanical Analysis of the Platelets Behavior in the Blood Flow Using Discrete Element Method

2000 ◽  
Author(s):  
Hisako Miyazaki ◽  
Hao Liu ◽  
Takami Yamaguchi
Keyword(s):  
Blood Flow ◽  
Vessel Wall ◽  
Thrombus Formation ◽  
Mechanical Analysis ◽  
Soluble Form ◽  
Blood Constituents ◽  
Fibrin Network ◽  
Insoluble Form ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Platelets play an important role in blood coagulation, particularly in the formation of primary thrombi. It is thought that the aggregation of platelets, which initiates primary thrombi formation, is mediated by a macromolecule called von Willebrand Factor (vWF). vWF is a long chain macromolecule that exists in the blood flow as a soluble form and in the vessel wall as an insoluble form. Figure 1 schematically shows normal (a) and pathological (b) thrombus formation processes as illustrated by Ikeda (1998) In both cases, platelets adhere to the injured vessel wall and then form a thrombus in cooperation with the fibrin network, red cells, and other blood constituents. vWF is thought to play a more important role in pathological thrombosis formation than in the normal hemostatic process, particularly due to its ability to react to hemodynamic stress.

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.

Mass Spectrometry of N-Benzoyl-2-hydroxyalkylamines. Role of the Hydroxylic Hydrogen in the Fragmentation Pattern

1975 ◽  
Vol 53 (21) ◽  
pp. 3175-3187 ◽  
Author(s):  
Don C. DeJongh ◽  
Denis C. K. Lin ◽  
Pierre LeClair-Lanteigne ◽  
Denis Gravel
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Hydroxyl Group ◽  
Fragmentation Pattern ◽  
Relative Importance ◽  
Hydrogen Atoms ◽  
Related Compounds ◽  
Double Hydrogen ◽  
Hydrogen Rearrangement

An interesting rearrangement has been observed in the mass spectra of a series of N-benzoyl-2-hydroxyalkylamines. The hydrogen atom of the hydroxyl group is transferred to the N-benzoyl portion of the molecular ion and the bond between positions 1 and 2 in the N-alkyl group is cleaved. A rearrangement ion, observed at m/e 135, is formed along with a neutral aldehyde or ketone. When the hydroxylic hydrogen is replaced by a trimethylsilyl substituent, the latter group is transferred with comparable efficiency. Differences in the relative importance of this rearrangement in the mass spectra of a series of related compounds with decreasing substitution at position 2, have been explained by differences in the stabilities of the neutral molecules formed along with m/e 135 and by the occurrence of a double hydrogen rearrangement which competes if hydrogen atoms are present in a relationship gamma and delta to the carbonyl group.

THE 3,4–DIPHENYLCHLOROCYCLOPENTENONES AND RELATED COMPOUNDS

1937 ◽  
Vol 15b (8) ◽  
pp. 321-330 ◽  
Author(s):  
C. F. H. Allen ◽  
H. Rudoff
Keyword(s):  
New Evidence ◽  
Related Compounds

The uncertainties as to structures in the 3, 4–diphenylchlorocyclopentenones have been cleared up by the synthesis of all four possible isomers and a study of their reactions. The investigation of the related indones has been continued, and an interpretation of new evidence is suggested.

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.

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