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: XX. METHANOL LIGNIN AND ITS RELATION TO THE SO-CALLED "PRIMARY LIGNIN" OF FRIEDRICH AND DIWALD

1936 ◽  
Vol 14b (1) ◽  
pp. 12-19
Author(s):  
E. G. King ◽  
Harold Hibbert
Keyword(s):  
Structural Change ◽  
Hydrochloric Acid ◽  
Sodium Bicarbonate ◽  
Prolonged Treatment ◽  
Carboxyl Groups ◽  
Preliminary Treatment ◽  
Wood Meal ◽  
Spruce Wood ◽  
And Behavior ◽  
Related Compounds

Pretreatment of spruce wood meal with cold 5% sodium hydroxide decreases the amount of lignin extractable with methanol and anhydrous hydrogen chloride (Hibbert-Brauns method). Such a prior treatment of the wood meal, either in an atmosphere of nitrogen or of air, apparently causes no structural change in the lignin as judged by the methoxyl content. The method of Friedrich and Diwald, which involves a preliminary treatment with 17% hydrochloric acid followed by addition of a hot alcohol, represents a much more drastic process than the Hibbert-Brauns method, as is indicated by the darker color, lower methoxyl content and behavior towards 8–10% alkali of the isolated lignin.Methanol lignin isolated front a resin-free spruce wood meal, previously subjected to treatment with 5% cold alkali in the presence or absence of air, shows no loss of methoxyl groups on treatment with 8–10% alkali; the same is true of the "primary lignin" prepared by the method of Friedrich and Diwald; in both cases the lignin is insoluble in sodium bicarbonate. These facts show that neither methanol lignin nor "native lignin" contains ester methoxyl groups, as assumed by Friedrich and Diwald. Prolonged treatment of methanol lignin with alkali in the presence of air, especially at higher temperatures, apparenthy brings about certain changes in its structure, including possibly the formation of carboxyl groups. The claim of Friedrich and Diwald that their product represents an "unchanged native lignin" is not in accordance with the facts, and their assumption of the presence of carboxyl groups in native lignin is incorrect.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: XXVIII. THE BEHAVIOR OF LIGNIN TOWARDS ACTIVATED HYDROGEN

1936 ◽  
Vol 14b (11) ◽  
pp. 404-407 ◽  
Author(s):  
R. G. D. Moore ◽  
Harold Hibbert
Keyword(s):  
Low Temperatures ◽  
Open Chain ◽  
Wood Meal ◽  
Building Unit ◽  
Negative Results ◽  
Spruce Wood ◽  
Related Compounds

Methylated methanol lignin prepared from fully methylated spruce wood-meal was subjected, at relatively low temperatures and pressures, to the action of hydrogen in the presence of catalysts, and under conditions such that reduction of open-chain ethylenic linkages readily occurs. Entirely negative results were obtained. This pointed to the absence of ethylenic linkages in the lignin building unit.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: II GLYCOL-LIGNIN AND GLYCOL-ETHER-LIGNIN

1930 ◽  
Vol 2 (6) ◽  
pp. 364-375 ◽  
Author(s):  
Harold Hibbert ◽  
Léo Marion
Keyword(s):  
Ethylene Glycol ◽  
Monomethyl Ether ◽  
Glycol Ether ◽  
Free Alcohol ◽  
Wood Meal ◽  
Spruce Wood ◽  
Related Compounds

The extraction of spruce wood meal with ethylene glycol in the presence of 0.05% HCl leads to the isolation of a lignin derivative to which the name glycol-lignin is given. If the monomethyl ether of glycol be substituted for the free alcohol, a glycol-ether-lignin is obtained which has a much higher methoxyl content than glycol-lignin. The product of extraction is therefore a compound of lignin and the solvent. A comparison of the methoxyl content of the derivatives obtained from the two lignins by methylation and hydrolysis supports this conclusion. On oxidation, glycol-lignin gives rise to a product which forms a p-bromphenylhydrazone, identical with that obtained from the product of the oxidation of ethylene glycol under the same conditions. On hydrolysis with acids glycol-lignin yields, besides 0.7% formaldehyde, a substance which reduces Fehling's solution.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: IX. ETHERS OF GLYCOL-LIGNIN

1931 ◽  
Vol 5 (3) ◽  
pp. 302-305
Author(s):  
Harold Hibbert ◽  
Léo Marion
Keyword(s):  
Sodium Hydroxide ◽  
Sodium Salt ◽  
Aqueous Sodium Hydroxide ◽  
Hydroxyl Groups ◽  
Acidic Properties ◽  
Aqueous Sodium ◽  
Spruce Wood ◽  
Free Hydroxyl ◽  
Chloro Derivatives ◽  
Related Compounds

Glycol-lignin prepared from spruce wood has been found to form a sodium salt which reacts with chloro-derivatives, giving rise to the corresponding glycol-lignin ethers. These compounds are insoluble in aqueous sodium hydroxide but still contain free hydroxyl groups which can be methylated without the ethereal linkage being broken. Hence glycol-lignin contains several free hydroxyl groups, one or more of which possess acidic properties. Both the methoxymethyl ether and the 2:4-dinitrophenyl ether of glycol-lignin have been prepared. The evidence would seem to indicate the presence of both phenolic and aliphatic hydroxyl groups.

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: III. GLYCEROL-CHLOROHYDRIN-LIGNIN

1930 ◽  
Vol 3 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Harold Hibbert ◽  
John Bernard Phillips
Keyword(s):  
Previous Evidence ◽  
Wood Meal ◽  
Spruce Wood ◽  
Extraction Agent ◽  
Related Compounds

Glycerol α-monochlorohydrin has been found to be an effective extraction agent for the removal of lignin from spruce wood meal. Previous evidence for the view that a compound is formed between the lignin and the extraction medium is supported by the results of methoxyl and halogen analysis, and those of hydrolysis.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: XXVII. METHYLATION AND STRUCTURE OF METHANOL LIGNIN (SPRUCE)

1937 ◽  
Vol 15b (1) ◽  
pp. 38-45 ◽  
Author(s):  
Jack Compton ◽  
Harold Hibbert
Keyword(s):  
Solvent Extraction ◽  
Sodium Hydroxide ◽  
Sulphuric Acid ◽  
Dimethyl Sulphate ◽  
Soluble Fraction ◽  
Anhydrous Methanol ◽  
Hydroxyl Groups ◽  
Slight Excess ◽  
Pure Methanol ◽  
Related Compounds

The composition of spruce methanol lignin prepared by the action of anhydrous methanol-hydrogen chloride on spruce meal was found to vary with the temperature and time of extraction. The reaction mixture contains two products, having methoxyl contents of 21.6 and 24%, respectively. Higher temperatures and longer time of heating favor formation of the latter. Long continued extraction of the crude methanol lignin with ether removed the second product (OCH3, 24%). This showed that this was a true "ether-soluble" fraction, but it was not found possible to isolate the pure methanol lignin (OCH3, 21.6%) by this process. The two substances can be separated either by solvent extraction or, as now shown, by use of 8–10% sodium hydroxide. Methylation of methanol lignin with dimethyl sulphate and alkali gives rise to the formation of new hydroxyl groups, the extent of the changes increasing markedly with rise in temperature of methylation and with increase in concentration of alkali used.A methanol lignin (OCH3, 22.3%) on repeated methylation yields a methylated lignin containing 37.2% methoxyl. Degradation during methylation is restricted by the use of acetone as solvent and only a slight excess of alkali (5–10%) at 20 °C. The results indicate the necessity for caution in the interpretation of data based on methylation experiments involving the use of alkali, and point to the presence of heterocyclic oxygen rings, non-furane in type, as part of the lignin structure. When refluxed for 48 hr. with 65 % aqueous methyl alcohol containing 9% sulphuric acid, ether-insoluble methanol lignin (OCH3, 22.3%) yielded a product with methoxyl content 21.3% which decreased to 20.9% when the product was treated for a further 52 hr.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: I. A NEW METHOD FOR THE ISOLATION OF SPRUCE WOOD LIGNIN

1930 ◽  
Vol 2 (6) ◽  
pp. 357-363 ◽  
Author(s):  
Harold Hibbert ◽  
H. J. Rowley
Keyword(s):  
Hydrochloric Acid ◽  
Ethylene Glycol ◽  
Ethyl Ether ◽  
Cold Water ◽  
New Method ◽  
Large Excess ◽  
Spruce Wood ◽  
Hydroxy Compounds ◽  
Related Compounds ◽  
Unchanged Form

A description is given of a new method for the isolation from spruce meal of lignin in apparently a relatively unchanged form. The method consists in first extracting the spruce meal with a mixture of equal volumes of benzene and alcohol, followed by an extraction with water. The dried meal is then digested for 6–8 hr. at 110 °C. with 8–10 times its weight of ethylene glycol containing 0.2% of iodine, calculated on the weight of spruce meal taken. The reaction mixture is filtered, and the lignin isolated by pouring the filtrate into a large excess of cold water. Other catalysts such as hydrochloric acid may be used in place of iodine and the glycol may be replaced by a variety of hydroxy-compounds such as glycol mono-ethyl ether, glycerol, chlorhydrins, hydroxyacids, etc.

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 Kinetics of Substituted Bis- and Mono-azo Dyes as Corrosion Inhibitors for Aluminium in Hydrochloric Acid and Sodium Hydroxide Solutions

1999 ◽  
Vol 23 (7) ◽  
pp. 408-409
Author(s):  
Loutfy H. Madkour ◽  
R. M. Issa ◽  
I. M. El-Ghrabawy
Keyword(s):  
Hydrochloric Acid ◽  
Sodium Hydroxide ◽  
Azo Dyes ◽  
Thermodynamic Model ◽  
Corrosion Inhibitors ◽  
Kinetics Of ◽  
Alkaline Corrosion

This investigation is designed to apply an advanced kinetic–thermodynamic model on the data obtained from acidic and alkaline corrosion of aluminium using bis- and mono-azo dyes as corrosion inhibitors.

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