Acetic Acid-hydrochloric Acid Research Articles

Facile synthesis of acid catalyzed sulfonic acid-amide functionalized magnetic sodium alginate and its efficient adsorption for ciprofloxacin and moxifloxacin

Environmentally friendly magnetic sodium alginate beads with glutaraldehyde cross-linking catalyzed by acetic acid-hydrochloric acid were successfully designed (FSSi@SA), and the magnetic bio-sorbents after amide reaction (FSSi@SA-sula) were utilized to absorb fluoroquinolone antibiotics in water. After amidation, FSSi@SA-sula exhibited strong pH adaptability (pH = 6.0–12.0). Langmuir and pseudo-first-order models can better describe the isotherm and kinetic process well, respectively. Under the optimization conditions with pH = 7 and temperature of 318.15 K, the maximum adsorption capacities of FSSi@SA-sula on the third-generation FQs ciprofloxacin (CIP) and the fourth-generation FQs moxifloxacin (MOX) respectively reached 365.66 and 149.57 mg g−1. The thermodynamics research indicated that the as-prepared FSSi@SA-sula is spontaneous and feasible. And after five adsorption cycles, the loss of adsorption capacity was less than 20% for both CIP and MOX, demonstrating the fine reusability and stability of the designed magnetic bio-sorbent. This study provides some ideas for facile synthesis of acid-catalyzed sodium alginate-glutaraldehyde cross-linking, which has promising applications in grafting various types of groups onto the retained carboxyl groups of sodium alginate spheres for the various contaminants removal in wastewater.

A novel method to convert triptolide into tripchlorolide inTripterygium wilfordii

A new method has been established to convert triptolide (1) into tripchlorolide (2) directly in the Chinese herbal drug Tripterygium wilfordii Hook F. and the influences of reaction times and pH values have been investigated. It was found that 1 could be most efficiently converted into 2 using a hydrochloric acid-acetic acid system. An HPLC method was devised in order to monitor the conversion and ESI-MS was used to identify the synthetic product 2. The sensitivity of the assay was sufficient to monitor the conversion of the main active components in T. wilfordii.

Separation of U(IV) and U(VI) by ion exchange chromatography on lanthanum ammonium oxalate

A new inorganic exchanger consisting of lanthanum ammonium oxalate (LAOX) has been prepared and studied, and application to the separation of U(IV) and U(VI) has been explored after measuring, by the batch exchange method, the distribution coefficients. A hydrochloric acid-acetic acid mixture represents the most appropriate medium, among those tested, for performing the separation. Sorption is negligible for U(VI) but is relevant for U(IV) and it can be ascribed to the formation of an insoluble lanthanum uranium and ammonium oxalate. Desorption is possible only by using as eluent a hot solution of EDTA.

Reaction of 2‐dimethylaminomethylene‐1,3‐diones with dinucleophiles. X. synthesis of 5‐substituted ethyl or methyl 4‐isoxazolecarboxylates and methyl 4‐(2,2‐dimethyl‐1‐oxopropyl)‐5‐isoxazolecarboxylate

AbstractReaction of ethyl or methyl 2‐dimethylaminomethylene‐3‐oxoalkanoates with hydroxylamine hydrochloride in methanol solution afforded in high yields the relative esters of 5‐substituted 4‐isoxazolecarboxylic acids II. These esters were hydrolyzed generally with concentrated hydrochloric acid‐acetic acid mixtures to the corresponding carboxylic acids in satisfactory yields.Ethyl or methyl esters II isomerized with sodium ethoxide or methoxide, respectively, to the corresponding esters or hemiesters of 2‐cyano‐3‐oxoalkanoic acids generally in excellent to satisfactory yields.Reaction of methyl 5,5‐dimethyl‐3‐dimethylaminomethylene‐2,4‐dioxohexanoate with hydroxylamine hydrochloride afforded in moderate yield methyl 4‐(2,2‐dimethyl‐1‐oxopropyl)‐5‐isoxazolecarboxylate, which was converted by acid hydrolysis as above to 4‐t‐butyl‐4‐hydroxyfuro[3,4‐d]isoxazol‐6‐(4H)‐one.

Pyrimidine Derivatives and Related Compounds, V Synthesis of Some Isoxazolo [2,3-a] pyrimidines. A New Ring System

3-Amino-5-phenyl-4-phenylazoisoxazole (1) reacts with ethyl acetoacetate to yield the corresponding ethyl isoxazolylaminocrotonate derivative (2) which could be thermally cyclized into the isoxazolopyrimidine derivative (4). On the other hand, condensation of 1 with ethoxymethylenemalononitrile has resulted in the formation of the aminoethylene derivative (5). Compound 1 reacted with acrylonitrile to yield the isoxazolo[2,3-a]pyrimidine derivative (6). The latter was converted into the corresponding exo derivative (8) by the action of acetic acid-hydrochloric acid mixture. Compound 1 also reacted with methoxycarbonyl-, ethoxycarbomyl- and benzoyl isothiocyanates to yield the isoxazolylthioureas (10a, b) and (11), respectively. The reaction of 2 with acetic acid-hydrochloric acid and with phenylhydrazine is reported.

Anion-exchange separation of thorium and protactinium from uranium matrix

The distribution behaviour of Th4+, Pa5+, and UO22+ ions between the anion-exchanger Amberlite IRA-400 and acetic acid-hydrochloric acid mixtures, has been investigated. It was found that the general behaviour of Th4+ ions is similar to that of UO22+ ions though the latter are much more highly adsorbed by the resin than Th4+. Protactinium exhibited a different behaviour from both Th4+ and UO22+ ions. The separation factors were calculated, and a Chromatographic procedure for sequential isolation of each element was developed.

ChemInform Abstract: PYRIMIDINE DERIVATIVES AND RELATED COMPOUNDS. II. SYNTHESIS OF SOME DERIVATIVES OF PYRIMIDO(1,2‐2′,3′)PYRAZOLO(1,5‐A)PYRIMIDINES, A NEW RING SYSTEM

AbstractDie 4‐Arylazo‐pyrazole (III) cyclisieren mit den Agenzien (II) bzw. (IV) zu den Pyrazolopyrimidinen (I) bzw. (V).

Anion-exchange separation of gold on deae-cellulose in acetic acid-hydrochloric acid media

Gold(III) is strongly retained on DEAE-cellulose columns from acetic acid-hydrochloric acid mixtures. The distribution coefficients of gold(III) on DEAE-cellulose are given as functions of both acetic acid and hydrochloric acid concentrations. The adsorption becomes enhanced to a great extent in the mixed acid media as compared with those in aqueous hydrochloric acid media, reaching a distribution coefficient of 500 in acetic acid−0.5 M hydrochloric acid (9:1). The ion-exchange system allows separation of gold(III) from large quantities of many other metals on a short column. Results of the separation and determination of gold in an anode slime consisting of a complicated matrix are included.

Reactions with β-cyanoethylhydrazine—II: Synthesis of some 4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidine derivatives

β-Cyanoethylhydrazine 1 reacts with benzoylacetonitrile 2 in refluxing ethanol to yield 5-amino-1-β-cyanoethyl-3-phenylpyrazole 4; in acetic acid acetyl-β-cyanoethylhydrazone 8 was obtained. Compounds 4 and 8 were readily cyclized into 2-phenyl-4,5,6,7-tetrahydropyrazolo[1,5-a]pyrimidin-5-one 5 by acetic acid-hydrochloric acid. 3-p-Chlorophenylazo-2-phenyl-4,5,6,4-tetrahydropyrazolo[1,5-a]pyrimidin-5-one 15 was synthesized by the action of 1 on the p-chlorophenylazo derivative of 2 and cyclization of the resulting aminopyrazole 12 by concentrated sulphuric acid. The arylidene derivative of benzoylacetonitrile 16 reacts with 1 in acetic acid to yield the correspondings β-cyanoethylhydrazones 17. Cyclization of 17 with acetic acid-hydrochloric acid led to the formation of the pyrazolo (1,2-b) pyrazole derivative 19. On the other hand, the 1-β-carboxyethylpyrazole derivative 20 was obtained by the action of 3% aqueous NaOH.

Anion-exchange separation of Te(IV) from Te(VI), Se(IV) and Se(VI) on deae-cellulose in mixed hydrochloric-acetic acid media

Te(IV) can be separated from Te(VI), Se(IV) and Se(VI) by adsorption of Te(IV) on a DEAE-cellulose column from a mixed 1 M hydrochloric acid-acetic acid solution (1:9, v/v). This allows a selective separation of Te (IV) from the other three species in widely different mole ratios.

Micro-determination of xylose in plasma.

A very sensitive method for the determination of xylose in plasma has been developed, which involves condensation of phloroglucinol with the furfural released from xylose by the action of hot hydrochloric acid-acetic acid. In the standard method duplicate analyses of plasma samples containing 0·667–2·667 mmol l–1 of xylose can be achieved by using 0·2-ml samples. A modified method using 0·1 ml of whole blood can also be used. The absorbance obtained on analysing solutions containing 1·333 nmol l–1 of xylose is 0·372 at 554 nm using cuvettes of 10-mm light path. This value corresponds to a molar absorption of approximately 33 000. By using hydrobromic acid-acetic acid an even higher molar absorption of approximately 39 000 is obtained. Glucose gives only a weak reaction under the test conditions, 417 nmol of glucose giving an absorbance equivalent to 7·6 nmol of xylose.

Reactions with β-cyanoethylhydrazine—I : A route for the preparation of pyrazolo[1.5-a]pyrimidines and pyrrolo[1.2-b]pyrrazoles

Malononitrile ( 1) reacts with β-cyanoethylhydrazine ( 2) to yield 5-amino-4-cyano-1-β-cyanoethyl-3-cyanomethyl-pyrazole ( 3). Treatment of 3 with 1% NaOH solution results in the formation of 3-cyano-2-cyanomethyl-4,5,6,7-tetrahydropyrazolo[1.5-a] pyrimine ( 6). On the other hand, when 3 was refluxed with acetic acid-hydrochloric acid mixture, the pyrido[3:4:3′:4′]pyrazolo[1.5-a] pyrimidine ( 10) was formed. 1,2-Dihydro-5-hydroxy-3-phenylazopyrazolo[1.5-a] pyrimidine ( 16) was obtained by cyclization of 3,5-dianimo-1-(β-cyanoethyl)-4-phenylazopyrazole ( 18), which, in turn, was obtained by the action of 2 on phenylazomalononitrile ( 17). Ethoxymethylenemalononitrile ( 20) reacts with 2 to yield 3-amino-4-cyano-1-β-cyanoethyl)-pyrazole ( 21). Compound 21 was readily cyclized into the pyrrolo[1.2-b]pyrazole derivative 25 by the action of either 3% NaOH solution or conc sulphuric acid.

Anion exchange of some elements in acetic acid-hydrochloric acid medium

A comparative study of the adsorbability of Cd(II), Ni(II), Mn(II), Ga(III), La(III), Mo(VI) and bromide from aqueous acetic acid solutions on' Dowex 1-X8, 100–200 mesh, in the acetate and chloride forms, proved that chloride ions are indispensable for high adsorption from concentrated acetic acid solutions. A study of the adsorption isotherms of Ni(II), Mn(II) and Cd(II) on the acetate-form resin from acetic acid-hydrochloric acid solutions, showed that these elements form anionic complexes. The K d values on RCl-exchanger, for a given acetic acid concentration, were highly dependent on the total exchange capacity of the resin. A simplified anion-exchange separation procedure in aqueous acetic acid was developed, with an adsorption step from a mixture of acetic and hydrochloric acids.

Anion-Exchange Separation of Germanium from Arsenic(III and V) and Other Elements in Hydrochloric Acid-Acetic Acid Medium

Abstract In this paper a highly selective method is described for the separation of micro- and milligram amounts of germanium from arsenic(III and V) as well as from many other metal ions by means of the strongly basic anion-exchange resin Dowex 1-X8. This separation procedure is based on the preferential elution of germanium tetrachloride from a column of this resin by means of a mixture consisting of 90% acetic acid and 10% 9 N hydrochloric acid, under which condition arsenic, iron, cobalt, copper, manganese, molybdenum, lead, bismuth, and several other metal ions are strongly retained by the resin as anionic chlorocomplexes while germanium passes into the eluate practically unadsorbed. For the final photometric determination of germanium directly in the eluate, a modification of the phenylfluorone method is employed.