Synthesis and structural characterization of a cocrystal salt containing acriflavine and 3,5-dinitrobenzoic acid

An acriflavine cocrystal salt with 3,5-dinitrobenzoic acid (stoichiometry 1:3) was synthesized and structurally characterized. This is the first crystal structure containing the acriflavine moiety to be documented and also the first in which a trimer of an aromatic monocarboxylic acid has been identified. In the crystal packing the trimers of 3,5-dinitrobenzoic acid form a porous organic framework, in the voids of which are located π-stacked columns of acriflavine cations.     

Three cocrystals and a cocrystal salt of pyrimidin‐2‐amine and glutaric acid

Four new cocrystals of pyrimidin‐2‐amine and propane‐1,3‐dicarboxylic (glutaric) acid were crystallized from three different solvents (acetonitrile, methanol and a 50:50 wt% mixture of methanol and chloroform) and their crystal structures determined. Two of the cocrystals, namely pyrimidin‐2‐amine–glutaric acid (1/1), C₄H₅N₃·C₆H₈O₄, (I) and (II), are polymorphs. The glutaric acid molecule in (I) has a linear conformation, whereas it is twisted in (II). The pyrimidin‐2‐amine–glutaric acid (2/1) cocrystal, 2C₄H₅N₃·C₆H₈O₄, (III), contains glutaric acid in its linear form. Cocrystal–salt bis(2‐aminopyrimidinium) glutarate–glutaric acid (1/2), 2C₄H₆N₃⁺·C₆H₆O₄²⁻·2C₆H₈O₄, (IV), was crystallized from the same solvent as cocrystal (II), supporting the idea of a cocrystal–salt continuum when both the neutral and ionic forms are present in appreciable concentrations in solution. The diversity of the packing motifs in (I)–(IV) is mainly caused by the conformational flexibility of glutaric acid, while the hydrogen‐bond patterns show certain similarities in all four structures.     

Complexes of cadmium with phosphoric acid

We have investigated the behaviour of¹⁰⁹Cd, in two-phase systems: (HDEHP–C₆ H₆/ H₃ PO₄–HClO₄–LiOH, =0.2), as a function of the independent equilibrium parameters which define the system: pH, equilibrium concentration of H₃ PO₄ and total concentration of HDEHP in the organic phase. The data have been interpreted in terms of the existence of phosphoric complexes characterized by their order 1 with regard to H₃ PO₄ and their charge z. The l and z. values are: 0<1<2, z=–2, 0, 1, 2 for the following ranges: 0.7<pH<2.7 and CH₃ PO₄<4M. Stability constants of the predominant complexes have been obtained. Finally, a formulation of these complexes has been proposed on the basis of partial charge of the atoms. Some complexes, could be formulated as hydroxy-phosphoric species, resulting from competition between hydroxy and dihydrogenophosphate anions. In concentrated phosphoric acid (CH₃ PO₄=4M), complexation of cadmium is not more than 25%.     

A 1:1 cocrystal of fluconazole with salicylic acid

The interaction of the antifungal pharmaceutical agent fluconazole with salicylic acid in acetonitrile solution yields the 1:1 cocrystal 2‐(2,4‐difluorophenyl)‐1,3‐bis(1H‐1,2,4‐triazol‐1‐yl)propan‐2‐ol–2‐hydroxybenzoic acid (1/1), C₁₃H₁₂F₂N₆O·C₇H₆O₃. The asymmetric unit consists of one molecule of fluconazole and one molecule of salicylic acid, both in their neutral forms. Both crystal agents form head‐to‐tail hydrogen‐bonded dimers, which are further connected into hydrogen‐bonded extended zigzag tapes propagating along the ac diagonal.     

盐酸法湿法磷酸中磷酸的协同萃取分离

选择对磷酸萃取率高 ,而对杂质的排斥性好的萃取剂 ,一直是业内人士长期关注的一个课题[1～ 3] 。本文以盐酸分解磷矿制得的粗磷酸为原料 ,对萃取磷酸的不同萃取剂如ＴＢＰ、ＴＲＰＯ、异戊醇、环己酮、环己醇等进行了筛选 ,最后选用体积比为 6∶4的三级逆流萃取和相比为 1∶2 .5的单级萃取 ,测定了各组分的分配系数和分离系数 ,并与使用其它萃取剂的结果作了比较。本文同时还测定了用 6 %ＨＣｌ水溶液和纯水对萃得有机相进行反洗的情况。1　实验部分1 1　试剂磷矿粉 ,40～ 1 0 0目 ,取自连云港锦屏磷矿 ;ＴＲＰＯ(三烷基氧化膦 ,加拿大Ｃ…     

Crystalline stoichiometric adducts of polyamides with phosphoric acid

It is shown the crystalline stoichiometric adducts of phosphoric acid with polyamides such as nylon 6 and poly-p-benzamide, and probably nylon 66, nylon 69, nylon 11, and nylon 12, can be prepared. These adducts are characterized by their unique wide-angle x-ray diffraction patterns and by rather low melting or decomposition temperatures. The thermal behavior and infrared data, indicate that interactions between the acid and the polymeric amide residues are weak.     

Catalytic phosphorylation of pentafluorophenol with phosphoric acid chlorides

Conclusions A new method was developed for the preparation of pentafluorophenyl phosphates, which consists in the catalytic phosphorylation of pentafluorophenol with POCl₃, or with aryl and polyfluoroalkyl phosphates, in the presence of the salts of the metals of Groups I and II of the periodic system.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 896–900, April, 1979.     

Condensation of n-alkyl-n-methylolamides of diethyl phosphoric acid with carboxylic acid amides

Conclusions Condensation of the N-alkyl-N-methylolamides of diethyl phosphoric acid (alkyls - methyl, ethyl, propyl, butyl, and amyl) with amides of formic, acetic, and chloroacetic acids and urethane gave the corresponding N-alkyl-N-(acylaminomethyl)amides of diethyl phosphoric acid; the products have been characterized.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 9, pp. 2133–2134, September, 1968.     

Probenecid and benzamide: cocrystal prepared by a green method and its physico-chemical and pharmaceutical characterization

Journal of Thermal Analysis and Calorimetry - The eco-friendly method of kneading was here used to synthesize a cocrystal of probenecid, an uricosuric drug used in treating gout and hyperuricemia,...     

Electrochemical behaviour of a lead electrode in phosphoric acid

 A lead electrode was studied in 6 and 12 M H₃PO₄. Oxidation of a freshly polished electrode occurred in the −0.5 to −0.3 V vs. SCE range, and led to PbHPO₄ growth on the electrode surface. The dissolution of this layer by electrochemical reduction occurred between −0.5 and −0.7 V. The influence of temperature (20 °C and 65 °C) was investigated and showed that the anodic and the cathodic peaks were increasing, and more markedly for the 12 M H₃PO₄. The ratio Q _cathodic/Q _anodic (Q=electrical charge flowing through the electrode) was equal or close to the unity at 20 °C and decreased as the temperature was increased. The influence of Cl⁻, Br⁻ and I⁻ ions was also evaluated. The addition of Cl⁻ and Br⁻ predominantly led to Pb₅(PO₄)₃Cl and Pb₅(PO₄)₃Br, respectively, while I⁻ led to a mixture of PbI₂ and PbHPO₄. Received: 18 July 1999 / Accepted: 2 November 1999     

Determination of uranium in wet phosphoric acid by extraction with octylphenylphosphoric acid

A method for quantitative determination of uranium in phosphoric acid and wet phosphoric acid has been developed. After reduction with Fe, uranium(IV) is extracted with a kerosene solution of octylphenylphosphoric acid. The uranium was stripped with 10M H₃PO₄, containing H₂O₂, and then determined spectrophotometrically with Arsenazo III and by direct uranium(IV)-phosphoric acid solution measurements.     

Thermodynamics of solvent extraction of thallium with diethylhexyl phosphoric acid

The equilibrium molalities Tl⁺ were measured in {Tl₂SO₄ + Na₂SO₄ + D₂EHPA + n-C₈H₁₈ + Water} system at ionic strength from 0.1 to 2.0 mol kg^?1 containing Na₂SO₄ as supporting electrolyte in aqueous phase and at constant molality extractant at temperatures from 278.15 K to 303.15 K in organic phase. The standard extraction constants K ⁰ at various temperatures were obtained by methods of extrapolation and polynomial approximation. Thermodynamic quantities for the extraction process were calculated.     

Study of vibrational spectra of polyaniline doped with sulfuric acid and phosphoric acid

Vibrational spectra of insulator emeraldine base (EB) form of polyaniline and electrical conductive sulfuric acid-and phosphoric acid-doped emeraldine salts (ES) were studied in the region of 4000-400 cm⁻¹ at ambient temperature by Fourier transform infrared spectroscopy. Infrared transmittance spectra of EB and ES were investigated to understand the bonding behavior of different organic and inorganic groups present in the polymeric chains and their structural variations on protonation by sulfate or phosphate ion inclusion in the polymer salt network. These studies revealed the para-coupling of deformed disubstituted benzenoid (B) and quinoid (Q) rings with ends capped predominantly by (B4Q1) units. The deformation of B and Q rings was confirmed by the appearance of many weak bands, very weak bands, and satellite structures in strong transmittance peaks of polymeric chain-constituting groups. Protonation takes place at the nitrogen sites of Q rings and forms semiquinone radical ions in ES. The vibrational bands pertaining to B rings, Q rings, B4Q1 units, semiquinone segment, sulfate ions, and phosphate ions were observed and assigned from these measurements. The shift in peak position of some bands with gain or loss in intensity and appearance of some new bands were observed in sulfuric acid-and phosphoric acid-doped ES spectra. These variations are attributed to the formation of new structural groups in ES on protonation and a change in crystalline field by sulfate and phosphate ion doping for crosslinking the polymeric chains.     

Fluorination of some phosphoric acid derivatives

Conclusions The stable complex of triethylamine with hydrogen fluoride is an effective reagent for the preparation of dialkyl fluorophosphates from various phosphoric acid derivatives containing a good leaving group.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1174–1176, May, 1988.     

Electrochemical treatment of wastewater from a phosphoric acid manufacturing plant

Phosphoric acid plant wastewater containing fluoride, phosphate and chemical oxygen demand etc., was treated using electrooxidation and electroflocculation methods. A maximum of 82% F- and 22.7% COD were removed using Ti/Pt(5c) under electrooxidative conditions. Electrooxidation with respect to F- removal is found mass-transfer limited, and removals below 5-6 mg/L F- are not achievable. Electroflocculation using Al anode resulted in better removal of F-, COD and PO4(3-). The various results obtained are discussed in this paper.