Dilute Mineral Acid Research Articles

ChemInform Abstract: REACTION OF Γ‐BROMOACETOACETYL BROMIDE WITH N‐PHENYLHYDROXYLAMINE DERIVATIVES: SYNTHESIS OF 1,2‐OXAZINE DERIVATIVES

AbstractDie N‐Aryl‐hydroxy‐lamine (I) ergeben mit (II) die Substitutionsprodukte (III), die zu den Oxazindionen (IV) cyclisieren.

Ion exchange and solvent extraction of the thiourea complex cation of technetium-99 from mineral acid solutions

Sorption of macroamounts of the technetium thiourea complex cation by a cation exchange resin was studied in HNO3 and HClO4 solutions as a function of the concentration and reaction time for pertechnetate with thiourea. The distribution ratio reaches the value of 103 and may be even higher (>104) when sorption proceeds from a solution of the solid complex in dilute perchloric acid. The complex cation is extracted from 0.25–1M HNO3 with solutions of the bis(1,2-dicarbollyl)cobalt(III) anion in nitrobenzene—chloroform (1:1), log D=2.75−2.95 being obtained. The preconcentration and separation of technetium on cation exchangers from dilute mineral acids would seem to be one field of application.

Kinetics of reaction of 5-phenyl-1,3,4-thiadiazol-2-diazonium ion with water

5-Phenyl-1,3,4-thiadiazol-2-diazonium ion (I) is transformed into 2-amino-5-phenyl-1,3,4-thiadiazol (II) in diluted mineral acids. The reaction rate measured in solutions of diluted sulphuric acid reaches its maximum at concentrations of 2 to 2.5M-H2SO4. The reaction intermediate is 5-phenyl-1,3,4-thiadiazol-2-diazo hydroxide (III). The rate-limiting step in formation of III consists in base-catalyzed reaction of the diazonium ion I with water; it is 4.3 times slower in 0.1M-D2SO4 than in 0.1m-H2SO4. Ratio of the rate constants of the transformation of the diazo hydroxide III into the diazonium ion I and into the amine II increases rapidly with increasing sulphuric acid concentration.

Reaction of .GAMMA.-bromoacetoacetyl bromide with N-phenylhydroxylamine derivatives: Synthesis of 1,2-oxazine derivatives.

The reaction of γ-bromoacetoacetyl bromide (1) with N-arylhydroxylamines (2) afforded N-(γ-bromoacetoacetyl)-N-arylhydroxylamines (3), which were treated with sodium methoxide to give 2-aryltetrahydro-2H-1, 2-oxazine-3, 5-dione (4). Treatment of 3 with hydroxylamine directly afforded the 5-oxime derivatives of 4 (7), which could be transformed to 4 by mild hydrolysis with dilute mineral acid.

The extraction of trace amounts of gold from different aqueous mineral acid solutions by diphenyl-2-pyridylmethane dissolved in chloroform

Diphenyl-2-pyridylmethane, a high molecular weight substituted pyridine has been examined and found to be a useful solvent extraction reagent. Its behaviour is similar to amines in that it forms salts with mineral acids. The acid ionization constant (pKBH+) determined spectrophotometrically has a value of 4.41±0.06 at 25 °C. A study of the partition behaviour of trace amounts of gold between mineral acid solutions and 0.1M diphenyl-2-pyridylmethane dissolved in chloroform indicates that the metal can be quantitatively extracted from dilute mineral acid solutions and also from concentrated hydrochloric acid media in a single extraction. Attempts have been made to gain an understanding of factors affecting the extraction of gold. Common anions have little effect on extraction in concentrations upto 1M. Separation factors of a number of metal ions relative to gold are reported for three mineral acid systems; and gold has been estimated in some synthetic samples using neutron activation technique by prior extraction with 0.1M solution of diphenyl-2-pyridylmethane dissolved in chloroform.

Research of naphthyridines

It is shown by means of the UV spectra that a singly charged ion due to protonation at the N(4) atom develops when benzo[b]-1,8-naphthyrid-10-ones are dissolved in dilute mineral acids. The oxygen of the carbonyl group is also protonated in 96% sulfuric acid. Salts of the phenoxide type are formed in the reaction of these compounds with aqueous sodium hydroxide solutions. The pKa values of benzo[b]-1,8-naphthyrid-10-ones determined spectrophotometrically in a sulfuric acid-water system range from −4.69 to −5.69, depending on the substituent in the 8 position, and correlate with the Hammett σp constants.

N-oxides of 4-(5-nonyl)pyridine and trioctylamine as extractants for cerium(IV) and its separation from thorium(IV)

Trace level cerium has been oxidized to the quadrivalent state with potassium dichromate and shown to be preferentially extracted from very dilute mineral acid solutions and also from moderate nitric acid media by 0.1M solutions of 4-(5-nonyl)pyridine oxide and trioctylamine oxide dissolved in xylene. The dependence of extraction on the type of N-oxide, acid concentration and the N-oxide concentration has been investigated. The influence of the concentration of salting-out agents is described. Separation factors for a number of metal ions relative to cerium(IV) are reported for 0.1 M 4-(5-nonyl)pyridine oxide/xylene-0.1M sulphuric acid system. The ratio of the D for Ce(IV) to that of Ce(III) is greater than 105, and the D for Ce(IV) is much greater than that for thorium(IV). Separation of cerium(IV) from thorium has been achieved from 0.1M sulphuric acid solutions using 0.1M 4-(5-nonyl)pyridine oxide/xylene as an extractant.

Chapter 9 Quantitative Determination of Nonhistone and Histone Proteins in Chromatin

Publisher Summary This chapter surveys the most common, existing analytical methods for quantitative nonhistone determinations, and introduces a procedure that is more advantageous in the analysis of the nonhistone moiety of nucleoprotein materials, especially in the presence of histones. The existing methods for quantitative determination of the nonhistone moiety in nucleoprotein material include (1) selective solubilization of histones and precipitation of DNA and nonhistones with dilute mineral acids, (2) quantitative determination of the nonhistones with polyacrylamide gel electrophoresis, and (3) quantitative determination after preparative fractionation of chromatin proteins. The cellogel electrophoresis allows a quantitative determination of chromatin nonhistones in the presence of histones. This method is based mainly on cellogel electrophoresis originally developed for histone analysis. In this method a prerequisite for the analyses is the fractionation of the nucleoprotein complex into the nucleic acids and the protein moiety. The analysis of chromosomal proteins by cellogel electrophoresis after a complete, prior separation of the protein moiety from the DNA by ultracentrifugation in high salt and urea concentrations represents a simple and very reliable way to determine histone and nonhistone quantities. The chapter also provides the examples of the quantitative determination of histones and nonhistones by cellogel electrophoresis.

Properties of Blended Cements Made from Rice Husk Ash

Rice husk ash containing silica in a highly reactive form is found to be an excellent ingredient for making either lime-rice husk ash or portland-rice husk ash cements. Properties of both types of cements were investigated by standard ASTM test procedures. Portland-rice husk ash cements containing up to 50% ash showed compressive strengths which were considerably higher than the control portland cements even at early ages of 3 and 7 days. Test data is presented to show that a unique property of the cements containing rice husk ash is their good resistance to dilute organic and mineral acids.

Synthesis, separation, identification and interconversion of riboflavin phosphates and their acetyl derivatives: a reinvestigation.

A reinvestigation of flavin phosphate synthesis, separation, identification, and interconversion was made in view of contradictory results in the literature. It has been confirmed that monochlorophosphoric acid is the best agent for selective 5'-monophosphorylation of riboflavin and derivatives. This reaction yields, however, invariably up to 20% of an isomer, which has been separated by preparative thick-layer chromatography and shown to be the 4'-monophosphate. All the earlier authors failed to detect this isomer which does not bind to flavodoxin. It equilibrates in dilute mineral acid to yield an 8:2 mixture of 5'-phosphate to 4'-phosphate by phosphate migration. The formation of 2',3',4'-triacetyl-flavin mononucleotide, according to Christie, S. M. H., Kenner, G. W. & Todd, A. R. (1954) J. Chem. Soc., 46-52, upon acid-catalysed acetylation of pure FMN, was confirmed. The same reaction under base catalysis, however, does not yield 2',3',4'-triacetyl-flavin mononucleotide as claimed by Khomutova, E. D., Shapiro, T. A., Mezentseva, M. W. & Berezovskii, V. M. (1965) Otd. Obshch. i. Tekhn. Khim., 241-244, Chem. Abstr. 65, 5516a, but in fact up to 80% 2', 3'-diacetyl-flavin 4':5'-cyclophosphate as the main product, which is stable under neutral and weak acidic conditions and does not hydrolyse to 2',3'-diacetyl-flavin 5'-monophosphate as claimed by McCormick, D.B. (1974) J. Heterocycl. Chem. 11, 969-974. The various flavin phosphates and their acetyl derivatives have been identified by pH-titration, electrophoresis, and proton magnetic resonance spectrometry, which direct analyses of crude reaction products as well as a rapid purity check of commerical FMN.

Possible relationship between soil fulvic acid and polymaleic acid

IN the course of structural investigations into the organic matter component of soil, it became clear that the fulvic acid solutions1 (the alkali-soluble fractions of humus not precipitated by acid) contained a high proportion of their soluble organic matter as a polymer, consisting of a carbon skeleton highly substituted by carboxyl groups. The solutions also normally contained peptide and polysaccharide mixtures or complexes which could be removed almost entirely by fractionation on charcoal2, a technique which allowed the isolation of the polycarboxylic acid. Brown acidic polymers virtually identical with those found in the fulvic acid solution were recovered from podzol Bh horizon humus by extraction of the soil with dilute mineral acid or trisodium citrate solutions pH 7.0) followed by dialysis.

STUDIES ON BEER HAZE FORMATION. II. DIMERIC FLAVANOIDS OBSERVED IN PROFILES OF BEER: NYLON 66 ADSORBATES

A peak in the gas chromatographic profile of beer: Nylon adsorbates has been found to comprise three unresolved biflavan components. One of these, molecular formula C30H26O12, consists of two C—C linked catechin units and has the same structure as a biflavan obtained by the acid catalysed interaction between cyanidiol and catechin. It appears to be the same as the procyanidin previously isolated from beer. The other components, both with molecular formula C30H26O13, have the same skeletal structure as the first, but are linked catechin-gallocatechin pairs, one being a prodelphinidin, the other a procyanidin. Dicatechin, a tannin obtained by treatment of catechin with dilute mineral acid, also seems likely to be a component of the adsorbate profiles.

The determination of chlorhydroxyquinoline in medicated pig feeds. Part II. Ultraviolet spectrophotometric batching assay and gas-chromatographic assay for mono- and dichloro components.

Two procedures have been developed for determining chlorhydroxyquinoline (halquinol) in pig feed medicated at a level of 120 p.p.m. The ultraviolet spectrophotometric procedure can be used to determine halquinol and the gas-liquid chromatographic procedure to determine specifically the 5,7-dichloro- and the combined 5- and 7-chloroquinolin-8-ol components. Halquinol was found to react with copper during the initial extraction with chloroform, thus preventing formation of the silyl ether prior to gas-liquid chromatography. Partitioning the chloroform extract with dilute mineral acid so as to cause dissociation of the chelate and adding EDTA before back-extraction into dichloromethane overcame this problem.

CARBONYL‐PROPYLENE GLYCOL INTERACTIONS IN FLAVOR SYSTEMS

ABSTRACTVariable organoleptic qualities and GC composition of a commercial cherry flavor were traced by GC‐MS to four variable components, benzaldehyde, tolualdehyde and their corresponding propylene glycol acetals. The formation of flavorless acetals was shown to consume 40–70% of the most important cherry flavor components between manufacture and use. The formation of acetals in propylene glycol flavor solvents was investigated with a variety of flavor‐important aldehydes. Acetals are quite stable under neutral and alkaline conditions and are only hydrolyzed by dilute mineral acids or moderate heat treatment. Utilization of flavors containing an unsuspected and unknown amount of acetal in food applications where hydrolysis does not take place can result in variable product flavor quality.

The 1,3,5-Trinitrobenzene–Phenoxide σ-Complex. Ambident Phenoxide Ion in SNAr Systems

1,3,5-Trinitrobenzene reacts with potassium phenoxide in dimethyl sulfoxide solution to yield a σ-complex in which bonding has occurred between the para carbon of the phenoxy moiety and an unsubstituted carbon of the nitroaromatic substrate. A minor proportion of ortho adduct is also obtained. When the reaction is performed in DMSO–MeOH (80:20, v/v) one obtains initially the methoxide adduct of TNB which is then smoothly transformed into the phenoxide adduct. The latter is stable to dilute mineral acid, unlike the former; formation of a σ-complex involving bonding between the phenoxy oxygen and a carbon of TNB is thereby excluded. The reaction represents the first instance of phenoxide ion acting as an ambident nucleophile towards aromatic carbon. The implication of this finding on the course of related SNAr reactions is discussed on the basis of kinetic and thermodynamic control of product formation.

The Hydrolysis of Some N-Acylaspartic and N-Acylglutamic Monoamides in Dilute Mineral Acid

The release of ammonia by hydrolysis of N-benzoyl-L-asparagine, glycyl-DL-asparagine, L-asparagine, and succinamic acid, and of aniline from N-benzoyl-L-glutamic-alpha-anilide, N-benzoyl-L-aspartic-alpha-anilide, L-aspartic-alpha-anilide, and the monoanilides of succinic and glutaric acids is first-order with respect to substrate in dilute (0.4-0.03 M) aqueous hydrochloric acid at 100 degrees C. The first-order rate constants (kobs) for these reactions can be expressed as kobs = kintra + k2[H+]. The above hydrolyses are used as models for developing a tentative mechanism to account for the selective release of aspartic acid from proteins under these condiditons. The data are also used to suggest reasons why glutamic acid is not released with equal facility.

Studies on Thorium Phosphate Ion Exchanger. Part III. Paper Chromatographic Behavior and Separations of Metal Ions on Thorium Phosphate Papers

Abstract Thorium phosphate papers have been prepared by treatment with thorium nitrate and phosphoric acid solutions. Several metal ions have been chromatographed on thorium phosphate paper. The effect of pH on RF values has been investigated. Some useful analytical separations of metal ions have been achieved by using only dilute mineral acid and a mixed solvent system.

Quantitative analysis of dammarane type saponins of ginseng and its application to the evaluation of the commercial Ginseng tea and Ginseng extract (author's transl)

On hydrolysis with dilute mineral acid, Ginseng saponins, ginsenosides-Rb1, -Rb2, -Rb3, -Rc, and -Rd yielded panaxadiol (IV), and ginsenosides-Re, -Rf, -Rg1, and -Rg2 and 20-glucoginsenoside-Rf afforded panaxatriol (X). The optimal condition of saponinhydrolysis for the quantitative analysis of IV and X was studied. The crude hydrolysates of methanol extract of Ginseng were trimethylsilylated with N-trimethylsilylimidazole and the saponin content was calibrated by the gas chromatographic determination of TMS-panaxadiol and TMS-panaxatriol, using diacetylhederagenin methyl ester as the internal standard. This procedure was applied to the evaluation of the commercial "Ginseng Tea" and "Ginseng Extract."

A Sequential Extraction Procedure for Studying the Distribution of Organic Fractions in Forest Humus Layers

A procedure is described for the separation of nine organic matter fractions from F and H horizons of forest floor materials formed under different vegetative cover. The extracts employed (and fractions obtained) were ethanol:benzene (A), dilute mineral acid (B), cold 0.1 N NaOH (H-1, F-1, F-2), and hot NaOH (H-2, F-3, F-4), with unextracted organic matter comprising the final fraction. Distribution between the fractions of carbon, and polysaccharides was investigated. Considerable variation was observed in the distribution of fractions among sites, and both between and within horizons. The significance of the fractions is discussed. It was concluded that the procedure was suitable for studying differences in distribution of organic fractions of forest floor materials, but required further modification for examination of the composition of fulvic fractions.

A new modification of the pomeranz–fritsch isoquinoline synthesis

Schiff's bases formed from a variety of alkoxybenzaldehydes and aminoacetaldehyde dimethyl acetal have been hydrogenated to the corresponding benzylamines and converted into N-tosylates. The latter are readily cyclised in dilute mineral acid to isoquinolines in a one-pot reaction; intermediates in this reaction are N-tosyl-1,2-dihydroisoquinolines which can be isolated. N-Benzyl-N-tosylaminoacetaldehyde dimethyl acetal on treatment with dilute acid under the same conditions as for the cyclisation reactions gave N-benzyl-N-tosylaminoacetaldehyde, and then N-tosylbenzylamine; other substituted benzylamino-acetal derivatives similarly when the benzyl group lacked sufficiently activating substituents for cyclisation of the acetal.