STUDIES ON LIGNIN AND RELATED COMPOUNDS.: PART VII. A KINETIC STUDY OF THE ACTION OF HYPOCHLOROUS ACID ON SPRUCE LIGNIN AND ITS BEARING ON THE CONSTITUTION OF THE SPRUCE LIGNIN MOLECULE

1931 ◽  
Vol 4 (3) ◽  
pp. 240-253
Author(s):  
Harold Hibbert ◽  
K. Austin Taylor
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Alkaline Solution ◽  
Catalytic Effect ◽  
Hypochlorous Acid ◽  
Aqueous Suspension ◽  
Rapid Absorption ◽  
Low Concentrations ◽  
Rapid Reaction ◽  
Related Compounds

The action of hypochlorous acid on glycol-lignin in finely divided aqueous suspension, and in alkaline solution, is autocatalytic, the autocatalysis being due to formation of hydrochloric acid, which catalyzes the reaction strongly. Nitric acid apparently acts only by increasing the concentration of undissociated hydrochloric acid. The effect of the hydrochloric acid may be a direct catalytic effect of undissociated hydrochloric acid, or may be due to formation of chlorine.A comparison of the amounts of hypochlorous acid absorbed, and hydrochloric acid formed, by methylated and unmethylated lignin indicates that if ketomethylene groups are present in lignin they do not enolize sufficiently to play any appreciable part in the rapid reaction between hypochlorous acid and lignin.The rapid absorption of hypochlorous acid by lignin, dissolved in alkali, indicates that there is probably about 15% of a phenol nucleus in lignin. This value is supported by the rapid absorption of bromine from bromine water at very low concentrations, by lignin dissolved in alkali, and is based on the assumption of only one atom of halogen entering the phenol nucleus, which is true in the case of vanillin. If two or three halogen atoms enter the nucleus, this value of 15% has to be divided by two or three. It represents, in any case, a maximum value.The phenol nucleus accounts for only one third, or less, of the total rapid hypochlorous acid absorption. The remainder is probably due to addition of hypochlorous acid to an ethylene linkage, chlorination of a phenol ether, or a combination of both reactions.

STUDIES ON LIGNIN AND RELATED COMPOUNDS: VI. THE MECHANISM OF AQUEOUS HALOGENATION

1931 ◽  
Vol 4 (2) ◽  
pp. 119-133 ◽  
Author(s):  
K. Austin Taylor ◽  
O. Maass ◽  
Harold Hibbert
Keyword(s):  
Hydrochloric Acid ◽  
Allyl Alcohol ◽  
Hydrobromic Acid ◽  
Catalytic Effect ◽  
Hypochlorous Acid ◽  
The Real ◽  
Unsaturated Compounds ◽  
Acid Addition ◽  
Hypobromous Acid ◽  
Chlorine Ions

The rates of addition of hypochlorous and hypobromous acids to several unsaturated compounds, under the influence of various catalysts, have been studied.The addition of hypochlorous acid to allyl alcohol and dipropenyl glycol is catalysed by both hydrogen and chlorine ions, the catalytic effects of these ions, mole for mole, being equal. The effect of hydrogen and chlorine ions, when added together as hydrochloric acid, is not the sum of their separate effects but is proportional to their product, indicating undissociated hydrochloric acid as the real catalyst. The catalytic effect of varying amounts of added hydrochloric acid is approximately proportional to the square of the amount added, again indicating undissociated hydrochloric acid as the real catalyst.The addition of hypobromous acid to allyl alcohol is catalysed by hydrochloric and hydrobromic acids to about the same degree. This catalysis of hypobromous acid addition by hydrochloric acid provides further support for the hypothesis of undissociated hydrochloric acid as the real catalyst in the addition of hypochlorous acid.This catalytic effect of undissociated halogen acid on the addition of hypohalous acids is put forward as an explanation of the greater rates of addition of hypochlorous and hypobromous acids from chlorine and bromine water as compared with solutions of hypochlorous and hypobromous acids.The addition of hypobromous acid to fumaric acid is not catalysed by hydrobromic acid but, on the other hand, is considerably decreased. It is catalysed, however, by hydrochloric acid, although not nearly to the same degree as the addition to allyl alcohol. This difference in behavior between fumaric acid and allyl alcohol shows the necessity for studying the effect of hydrochloric and hydrobromic acids on the rate of addition of hypobromous acid to a wide variety of unsaturated compounds, before any general theory of aqueous halogenation applicable to all types of unsaturated compounds can be put forward. The possible influence of conjugation has, however, been pointed out.An attempt has been made to apply the theory of hypohalous acid addition catalysed by undissociated halogen acid to the aqueous halogenation of phenols. The reaction between hypobromous acid and m-nitrophenol has been shown to be catalysed by hydrochloric acid although not to the same extent as by hydrobromic acid. This indicates hypobromous acid addition, catalysed by undissociated hydrobromic acid, as one of the mechanisms involved in the aqueous bromination of phenols.It has been pointed out that a similar mechanism cannot be the fastest one in the aqueous chlorination of phenols, since it is in disagreement with kinetic data of Soper and Smith (21), showing chlorine to react faster than hypochlorous acid with phenols.It has been shown that resorcinol and phloroglucinol do not fall under the general classification proposed by Soper and Smith for phenols. Even here, however, the main reaction between chlorine water and the phenol seems to involve chlorine rather than hypochlorous acid.It has been suggested that several parallel mechanisms may be involved in the aqueous halogenation of phenols and the necessity for further work in this field has been emphasized.

Extraction of iron, cobalt, nickel and copper with dibenzyl sulfoxide solution in toluene

1979 ◽  
Vol 44 (7) ◽  
pp. 2024-2031 ◽  
Author(s):  
František Vláčil ◽  
Huynh Dang Khanh
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Distribution Ratio ◽  
Separation Factor ◽  
Chromatographic Separation ◽  
The Other ◽  
Iron Cobalt ◽  
Cobalt Nickel ◽  
Factor Α

The dependence of the distribution ratio of the metal on the concentration of hydrochloric of nitric acid was examined for Fe, Co, Ni and Cu extraction with 0.05M solution of dibenzylsulfoxide in toluene. Iron is extracted considerably more than the other metals, and is better extracted from hydrochloric acid than from nitric acid. The separation factor αFe/M (for 8M-HCl) is of the order of 104; this is not sufficient for a separation of trace quantities of iron from Co, Ni and Cu, but even at lower concentrations of HCl (e.g., 5M) the values is high enough for extraction chromatographic separation. The composition of the iron solvate extracted from HCl or LiCl medium was determined to be HFeCl4.2 B (B = dibenzyl sulfoxide).

DETERMINATION OF TRACE AMOUNTS OF SILVER IN GALENA ORES

1960 ◽  
Vol 38 (9) ◽  
pp. 1488-1494 ◽  
Author(s):  
E. J. Bounsall ◽  
W. A. E. McBryde
Keyword(s):  
Aqueous Solution ◽  
Nitric Acid ◽  
Sodium Chloride ◽  
Hydrochloric Acid ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Silver Content ◽  
Aqueous Sodium Chloride Solution ◽  
Aqueous Sodium

An analytical method is described for the determination of microgram amounts of silver in galena ores, based on the "reversion" of silver dithizonate. Silver is separated from relatively large amounts of lead by extraction as dithizonate into chloroform from an aqueous 1:99 nitric acid solution. Separation from mercury, which is also extracted under these conditions and would, if present, interfere in the analysis, is achieved by reverting the dithizonate solution with a 5% aqueous sodium chloride solution which is also 0.015 molar in hydrochloric acid. Following dilution of this aqueous solution and adjustment of pH, silver is again extracted into chloroform as the dithizonate, and determined absorptiometrically. Analyses of a number of galena ore samples showed a precision of within 3% for a silver content ranging from 0.03 to 0.4%.Some other methods for isolating silver from these samples, which were tried but found unsatisfactory, are discussed.

scholarly journals The differential effect of synthetic growth substances and other compounds upon plant species II. Seed germination and early growth responses to some arylcarbamic esters and related compounds

1946 ◽  
Vol 133 (873) ◽  
pp. 480-485 ◽  
Keyword(s):  
Seed Germination ◽  
Differential Effect ◽  
Marked Effect ◽  
Early Growth ◽  
Growth Substances ◽  
Growth Responses ◽  
Low Concentrations ◽  
Dicotyledonous Plants ◽  
Related Compounds ◽  
Synthetic Growth

The preparation and biological examination of a number of arylcarbamic esters (arylurethanes) are described. The experiments demonstrate the marked effect of iso propyl phenylcarbamate and some related compounds in very low concentrations upon the germination and seedling growth of cereals. The absence of effect of the same compounds in similar concentrations upon some dicotyledonous plants is noted.

scholarly journals Enhanced Adsorption of Methanol by Oxidised Nutshell Carbon

2000 ◽  
Vol 18 (3) ◽  
pp. 261-266 ◽  
Author(s):  
Alan Bailey ◽  
Mike Williams ◽  
Lyndsay Dunne ◽  
Lynne Beames
Keyword(s):  
Nitric Acid ◽  
Water Adsorption ◽  
Opposite Effect ◽  
Kinetics Of Adsorption ◽  
Dry Air ◽  
Low Concentrations ◽  
Methanol Vapour ◽  
Adsorption Reduction ◽  
Enhanced Adsorption ◽  
Kinetics Of

A nutshell charcoal was oxidised and reduced and the effect of the treatments on the water adsorption isotherms and methanol vapour penetration noted. Oxidation with 6 M nitric acid increased the penetration times for methanol vapour in dry air, not by just raising the dynamic capacity at low concentrations but also by improving the kinetics of adsorption. Reduction caused the opposite effect. The improvement in the adsorption kinetics is thought to be due to surface diffusion on to the oxidised surface of the transport pores.

scholarly journals Micro-crystalline structure of platinum

1902 ◽  
Vol 69 (451-458) ◽  
pp. 433-435
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Crystalline Structure ◽  
Aqua Regia ◽  
Pure Platinum ◽  
Small Ingot

The crystalline structure of platinum does not appear to have been studied, although it forms an interesting subject for investigation. A small ingot of pure platinum was obtained for the experiments. A section was cut therefrom and machined to 5/16 inch square and 1/10 inch in thickness. The section was then carefully polished and etched in aqua regia of the following strength :— 4 parts of hydrochloric acid (sp. gr. 1·2). 1 part of nitric acid (sp. gr. 1·42).

The autotrophic nutrition of symbiotic marine coelenterates with special reference to hermatypic corals. I. Movement of photosynthetic products between the symbionts

1971 ◽  
Vol 178 (1050) ◽  
pp. 111-129 ◽  
Keyword(s):  
Amino Acids ◽  
Organic Nitrogen ◽  
Sea Water ◽  
Nitrogen Compounds ◽  
Organic Substances ◽  
Low Concentrations ◽  
Steady Rate ◽  
Hermatypic Corals ◽  
Photosynthetic Products ◽  
Related Compounds

When symbiotic coelenterates, especially hermatypic corals, were incubated in the light in sea water containing NaH 14 CO 3 , small quantities of fixed 14 C were released from the tissues at a steady rate over 4 h. The rate of release was greatly increased in the presence of glycerol, glucose and alanine; the additional 14 C released was in the same substance as that added to the medium. The following related compounds had little or no effect on 14 C release : ethylene glycol, sorbose, fructose, glucosamine, glycine, proline, serine and glutamic acid. Such results have been previously reported in other symbiotic systems, and the substances causing the specific release of fixed 14 C are believed to be those which move from the autotrophic to the heterotrophic symbiont. This belief is supported here by previous observations that glycerol, glucose and alanine are among the most important organic substances released by freshly isolated zooxanthellae. Ammonium chloride increased the amount of fixed 14 C released by corals into alanine media, possibly due to conversion of ammonia to amino acids by zooxanthellae. Appreciable release of 14 C fixed in the dark also occurred into alanine solutions. These results suggest possible roles of zooxanthellae in supplying organic nitrogen compounds to the host cell at night as well as during the day. The involvement of zooxanthellae in ‘recycling’ nitrogen compounds within the association may help to explain the success of corals in seas poor in nutrients. There was substantial utilization of external glycerol and glucose when supplied at either high or low concentrations. Corals may well be able to utilize some of the small amounts of organic matter dissolved in sea water in the natural environment.

New reaction for free hydrochloric acid

1906 ◽  
Vol 6 (1) ◽  
pp. 58-58
Author(s):  
F. Simon
Keyword(s):  
Nitric Acid ◽  
Hydrochloric Acid ◽  
Gastric Juice ◽  
Free Hydrochloric Acid ◽  
Blue Coloration

For the discovery of free hydrochloric acid in gastric juice, Dr. Simon proposes a new reaction based on the properties of guaiac gum to oxidize in the presence of various oxidants (for example, nitric acid) and give a characteristic blue coloration.

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