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.

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: 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: 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: 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: XVII. METHYLATION OF WILLSTÄTTER AND FREUDENBERG LIGNINS

1935 ◽  
Vol 13b (2) ◽  
pp. 78-87 ◽  
Author(s):  
Fritz Brauns ◽  
Harold Hibbert
Keyword(s):  
Molecular Weight ◽  
Hydrogen Chloride ◽  
Methyl Alcohol ◽  
Methoxyl Group ◽  
Oxide Ring ◽  
Phenol Derivatives ◽  
The Difference ◽  
Derivatives Of ◽  
Related Compounds

Both Willstätter and Freudenberg lignins when treated with diazomethane give methylated products containing one additional methoxyl group, calculated on the basis of a molecular weight of about 850 for native lignin. When heated with phenol in the presence of a small amount of hydrogen chloride, both diazomethane-methylated lignin derivatives are converted into soluble phenol lignin derivatives containing one more methoxyl group than the corresponding phenol derivatives prepared from original, untreated Willstätter and Freudenberg lignins. This higher methoxyl value is also shown by the former phenol lignins on acetylation. The diazomethane-methylated phenol lignin derivatives prepared from diazomethane-methylated Willstätter and Freudenberg lignins correspond with the diazomethane-methylated phenol lignin derivatives prepared from original Willstätter and Freudenberg lignins. Also the fully methylated derivatives prepared from the phenol diazomethane-methylated Willstätter and Freudenberg lignins correspond with those described previously (2). The difference in methoxyl value between the phenol derivatives obtained from Willstätter lignin and the corresponding derivatives from Freudenberg lignin of 0.8–2.1% may be due possibly to the presence in the Freudenberg lignin of a methylene oxide ring which is removed in the isolation of Willstätter lignin, thus giving rise to the higher methoxyl content in the methylated derivatives of the latter. The action of methyl alcohol on original, on diazomethane-premethylated, and on fully methylated Willstätter and Freudenberg lignins was also investigated.

Studies on the Lignin of Eucalyptus regnans. III. The Isolation of an Alkali Lignin from Sulphate Pulping

1949 ◽  
Vol 2 (1) ◽  
pp. 117
Author(s):  
JWT Merewether
Keyword(s):  
Acetic Anhydride ◽  
Alkaline Hydrolysis ◽  
Empirical Formula ◽  
Benzoyl Chloride ◽  
Dimethyl Sulphate ◽  
Hydroxyl Groups ◽  
Equivalent Weight ◽  
Eucalyptus Regnans ◽  
Alkali Lignin ◽  
Hydrolysis Of

An alkali lignin containing no sulphur has been obtained as a by-product from the sulphate pulping of Eucalyptus regnans. Like other alkali lignins it contains hydroxyl groups, both acidic and alcoholic, as well as methoxyl groups. Acetic anhydride in pyridine yields an octoacetyl derivative which is readily hydrolysed by boiling water to a heptacetyl derivative. In pyridine, benzoyl chloride yields an octobenzoyl derivative while in aqueous alkali it yields a hexabenzoyl compound. Dimethyl sulphate yields a heptamethyl alkali lignin, diazomethane a hexamethyl derivative, while cold alkaline hydrolysis of the latter gives a pentamethyl derivative, and hot alkaline hydrolysis yields an anhydrotrimethyl alkali lignin. One of the methoxyl groups formed by methylation is unstable to acetylation by acetic anhydride in pyridine, heptamethyl alkali lignin yielding a hexamethyldiacetyl derivative, hexamethyl alkali lignin a pentamethyltriacetyl derivative, pentamethyl alkali lignin a tetramethyltetracetyl derivative, and anhydrotrimethyl alkali lignin the corresponding anhydrodimethyltetracetyl alkali lignin. Triphenylchloromethane in pyridine yields a monotrityl derivative.p-Nitrophenylhydrazine gives a di-p-nitrophenylhydrazone and phenylhydrazine a phenylhydrazone-osazone. Potentiometric titration shows two points of inflection and an equivalent weight of 863. The data are consistent with the empirical formula C92Hl04O34(1754) or C73H54O9,(OCH3)14,(OH)3,C(OH),CO-CH20H,C0,COOH

Synthesis and Structure Assignment of 2-(4-Methoxybenzyl)cyclohexyl β-D-Glucopyranoside Enantiomers

2006 ◽  
Vol 71 (10) ◽  
pp. 1470-1483 ◽  
Author(s):  
David Šaman ◽  
Pavel Kratina ◽  
Jitka Moravcová ◽  
Martina Wimmerová ◽  
Zdeněk Wimmer
Keyword(s):  
Analytical Data ◽  
Chiral Hplc ◽  
Nmr Analysis ◽  
Target Structure ◽  
Enantiomerically Pure ◽  
Whole Cells ◽  
H Nmr ◽  
Structure Assignment ◽  
Related Compounds ◽  
C Nmr

Glucosylation of the cis- and trans-isomers of 2-(4-methoxybenzyl)cyclohexan-1-ol (1a/1b, 2a/2b, 1a or 2a) was performed to prepare the corresponding alkyl β-D-glucopyranosides, mainly to get analytical data of pure enantiomers of the glucosides (3a-6b), required for subsequent investigations of related compounds with biological activity. One of the employed modifications of the Koenigs-Knorr synthesis resulted in achieving 85-95% yields of pure β-anomers 3a/3b, 4a/4b, 3a or 4a of protected intermediates, with several promoters and toluene as solvent, yielding finally the deprotected products 5a/5b, 6a/6b, 5a or 6a as pure β-anomers. To obtain enantiomerically pure β-anomers of the target structure (3a, 4a, 5a and 6a) for unambiguous structure assignment, an enzymic reduction of 2-(4-methoxybenzyl)cyclohexan-1-one by Saccharomyces cerevisiae whole cells was performed to get (1S,2S)- and (1S,2R)-enantiomers (1a and 2a) of 2-(4-methoxybenzyl)cyclohexan-1-ol. The opposite enantiomers of alkyl β-D-glucopyranosides (5b and 6b) were obtained by separation of the diastereoisomeric mixtures 5a/5b and 6a/6b by chiral HPLC. All stereoisomers of the products (3a-6b) were subjected to a detailed 1H NMR and 13C NMR analysis.

The preparation of sodium 4-Amino-3-nitro-benzenesulfonate and some related compounds

1982 ◽  
Vol 35 (8) ◽  
pp. 1727 ◽  
Author(s):  
J Rosevear ◽  
JFK Wilshire
Keyword(s):  
Sodium Hydroxide ◽  
Nitro Group ◽  
Sodium Salt ◽  
Sulfonic Acid ◽  
Sodium Hydroxide Solution ◽  
Hydroxide Solution ◽  
Dilute Sodium Hydroxide ◽  
Related Compounds

The sodium salt of 4-amino-3-nitrobenzenesulfonic acid (O-nitroaniline-p-sulfonic acid) has been prepared by the action of dilute sodium hydroxide solution on ethyl [(4-chlorosulfonyl-2-nitro)- phenyllcarbamate. Central to this synthesis is the finding that the N-ethoxycarbonyl group, when located ortho to a nitro group (but not to a bromo group), is readily removed by dilute sodium hydroxide solution.

Enhanced Thermal Stability of Esterified Lignin in Different Solvent Mediums

2018 ◽  
Vol 9 (1) ◽  
pp. 39-49 ◽  
Author(s):  
Sharifah Nurul Ain Syed Hashim ◽  
Sarani Zakaria ◽  
Chin Hua Chia ◽  
Sharifah Nabihah Syed Jaafar
Keyword(s):  
Thermal Stability ◽  
Alkaline Solution ◽  
Room Temperature ◽  
Hydroxyl Groups ◽  
Aqueous Alkaline Solution ◽  
Alkali Lignin ◽  
Weight Percentage ◽  
H Nmr ◽  
Ft Ir ◽  
Thermal Stability Of

In this study, soda alkali lignin from oil palm empty fruit bunch (EFB-AL) and kenaf core (KC-AL) are esterified with maleic anhydride under two different conditions, namely i) pyridine at temperature of 120°C for 3h and ii) aqueous alkaline solution at room temperature for 4h. As a result, the weight percentage gain (WPG) of the esterified EFB-AL (EFB-EL) and esterified KC-AL (KC-EL) in pyridine demonstrated a higher compared to aqueous alkaline solution. The FT-IR results of EFB-EL and KC-EL in both solvents exhibited some changes at the carbonyl and hydroxyl groups. Furthermore, the esterification process induced the carboxylic peak to appear in both alkali lignin samples. The outcome is confirmed by conducting H-NMR analysis, which demonstrated ester and carboxylic acid peaks within the spectral analysis. Finally, the TGA results showed both EFB-EL and KC-EL that are exposed to aqueous alkaline actually possessed better thermal stability and higher activation energy (Ea) compared to the esterified samples in pyridine.

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