STUDIES ON LIGNIN AND RELATED COMPOUNDS: XXIX. A STUDY OF THE ACIDIC HYDROXYL GROUPS IN SPRUCE LIGNIN

1937 ◽  
Vol 15b (12) ◽  
pp. 532-535 ◽  
Author(s):  
R. G. D. Moore ◽  
George F. Wright ◽  
Harold Hibbert
Keyword(s):  
Phenolic Content ◽  
Hydriodic Acid ◽  
Hydroxyl Groups ◽  
Aromatic Content ◽  
Related Compounds

A demethylated spruce lignin suitable for further study has been obtained by treating methylated methanol lignin with hydriodic acid. This treatment removes the aliphatic hydroxyl, and leaves 6.9 aromatic and 0.6 carboxylic hydroxyl groups per kg. On the basis of the phenolic content it is estimated that the maximum aromatic content of spruce lignin is about 40 to 45%.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: XXII. FRACTIONATION OF METHANOL LIGNIN

1936 ◽  
Vol 14b (4) ◽  
pp. 115-119
Author(s):  
Jack Compton ◽  
Margaret Greig ◽  
Harold Hibbert
Keyword(s):  
Pure State ◽  
Soluble Fraction ◽  
Hydroxyl Groups ◽  
Related Compounds

Preparation of methanol lignin by the method of Brauns and Hibbert on a larger scale than that employed previously has disclosed the presence of a second fraction, soluble in ether-dioxane. The original methanol lignin and this new fraction are obtained in a pure state by fractionation with dioxane and benzene. The former has been shown to correspond to the methanol lignin from which the Brauns and Hibbert formula C42H32O6(OCH3)6(OH)4 was derived. The benzene-dioxane–soluble fraction has been methylated and acetylated, and shown to have a different composition, the ratio of methoxyl to hydroxyl groups being 5:3.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: XV. PHENOL GLYCOL LIGNIN

1935 ◽  
Vol 13b (1) ◽  
pp. 55-60
Author(s):  
Fritz Brauns ◽  
Harold Hibbert
Keyword(s):  
Condensation Product ◽  
Hydroxyl Groups ◽  
Nuclear Condensation ◽  
Condensation Products ◽  
Related Compounds

Phenol condensation products of glycol lignin, of a premethylated and a fully methylated glycol lignin have been prepared. In each case it has been found that, on the basis of the five methoxyl groups present in the original glycol lignin, three molecules of phenol react with one lignin unit by nuclear condensation, and when the product is worked up immediately no loss of methoxyl groups occurs. With the fully methylated glycol lignin in one experiment, some of the methoxyl groups were removed but the hydroxyl groups thus formed could not be remethylated with diazomethane, thus indicating their probable aliphatic character. Quercetin does not give a phenol condensation product under the same conditions.

A Study of Reduction with Hydriodic Acid: Use in Micro Determinations of Hydroxyl Groups

1938 ◽  
Vol 60 (11) ◽  
pp. 2723-2726 ◽  
Author(s):  
Herschel K. Mitchell ◽  
Roger J. Williams
Keyword(s):  
Hydriodic Acid ◽  
Hydroxyl Groups

Kinetic Study on the Esterification of Hexanoic Acid with N,N-Dialkylamino Alcohols: Evidence for an Activation by Hydrogen Bonding

2006 ◽  
Vol 61 (5) ◽  
pp. 583-588 ◽  
Author(s):  
Stefan Breitenlechner ◽  
Thorsten Bach
Keyword(s):  
Hydrogen Bonding ◽  
Rate Increase ◽  
Order Rate Constant ◽  
Hexanoic Acid ◽  
Hydroxyl Groups ◽  
First Order ◽  
Moderate Rate ◽  
Pseudo First Order ◽  
Related Compounds ◽  
Membered Transition State

The pseudo-first order rate constant for the esterification of hexanoic acid (1) and five different N,N-dialkylamino alcohols (2) was determined in comparison to 1-hexanol (k = 0.67 · 10−5 s−1). The values range from 0.60 · 10−5 s−1 to 9.3 · 10−5 s−1. The data suggest a differing reactivity for structurally related compounds, which is directly correlated to the ability of the corresponding amino alcohol to activate the carboxylic acid by hydrogen bonding. A seven-membered transition state C≠ is postulated for reactions of 2-amino alcohols. The fastest reaction was observed for trans-2-(N,N-dimethylamino) cyclohexanol (2e), in which the amino and the hydroxyl groups are in an almost perfect synperiplanar 1,2-position. Attempts to further enhance the rate of the esterification by the addition of potential catalysts failed. Only Cu(OTf)2 (2.5 mol-%) allowed for a moderate rate increase from 7.5 · 10−5 s−1 (uncatalyzed) to 14.8 · 10−5 s−1 (catalyzed) in the esterification of hexanoic acid (1) with 2-(N,N-dimethylamino)ethanol (2a).

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.

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.

THE STRUCTURE OF HYOCHOLIC ACID

1956 ◽  
Vol 34 (11) ◽  
pp. 1528-1531 ◽  
Author(s):  
P. Ziegler
Keyword(s):  
Hydroxyl Groups ◽  
Hyocholic Acid ◽  
Related Compounds

Further evidence for the α-configuration of the hydroxyl groups in hyocholic acid is presented and several related compounds are described.

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