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1.
A new liquid emulsion membrane (LEM) process for uranium extraction from either dihydrate 28-30% P2O5 (DH) or hemi-dihydrate 42-45% P2O5 (HDH) wet process phosphoric acid is proposed. In this process, the organic component of the LEM is composed of a synergistic mixture of 0.1M di-2-ethyl hexyl phosphoric acid (DEHPA) and 0.025M trioctyl phosphine oxide (TOPO) with 4% Span 80. The internal or the strip acid phase is composed of 0.5M citric acid. The prepared LEM was proved to be stable in 42-45% P2O5 acid concentration range and can, therefore, be applied to the phosphoric acid produced by the hemi-dihydrate process. After breakdown of the loaded emulsion, the uranyl citrate in the internal strip phase is separated by adding methanol followed by its calcination to the orange oxide. Most of the reagents used are recycled. The proposed process is characterized by simplicity, practically closed operation cycle in addition to lower capital and operating costs. 相似文献
2.
Socorro Leyva 《Journal of fluorine chemistry》2010,131(10):982-1116
An alternative synthetic pathway to prepare norfloxacin analogues is presented. Three Lewis acids (CeCl3·7H2O, AlCl3·6H2O, ZnCl2) and one Brönsted acid (TsOH) were tested as catalysts in the preparation of 3,4-difluoroacrylate. Cyclization of this acrylate at 55 °C was achieved with the use of Eaton's reagent (P2O5/MeSO3H) a known Brönsted acid. The fluoroquinolone-boron complex presented high yields on C-7 nucleophilic substitution of the fluorine atom by different heterocyclic amines with low, medium and strong nucleophilic character. 相似文献
3.
V. R. Sinyakov T. V. Mezhenkova V. M. Karpov Ya. V. Zonov 《Russian Journal of Organic Chemistry》2016,52(10):1427-1431
Decarboxylation of (heptafluoronaphthalen-2-yl)acetic acid in DMF in the presence of NaHCO3 gave 2-methylheptafluoronaphthalene, and treatment with PCl5 on heating afforded dichloro(heptafluoronaphthalen-2-yl)acetic acid. Decarboxylation of the latter in DMF led to the formation of 2-(dichloromethyl)-heptafluoronaphthalene which was converted to 2-(difluoromethyl)heptafluoronaphthalene by heating with cesium fluoride. 相似文献
4.
S. Franklin T. Balasubramanian 《Acta Crystallographica. Section C, Structural Chemistry》2009,65(2):o58-o61
Both maleic and fumaric acid readily form adducts or complexes with other organic molecules. The 1:1 adduct formed by quinolin‐8‐ol (oxine) with maleic and fumaric acid are salts, namely 8‐hydroxyquinolinium hydrogen maleate, C9H8NO+·C4H3O4−, (I), and 8‐hydroxyquinolinium hydrogen fumarate, C9H8NO+·C4H3O4−, (II). The cations and anions of both salts are linked by ionic N+—H...O− hydrogen bonds. The maleate salt crystallizes in the space group P212121, while the fumarate salt crystallizes in P. The maleic and fumaric acids in their complex forms exist as semimaleate and semifumarate ions (mono‐ionized state), respectively. Classical N—H...O and O—H...O hydrogen bonds, together with short C—H...O contacts, generate an extensive hydrogen‐bonding network. The crystal structures of the maleate and fumarate salts of oxine have been elucidated to study the importance of noncovalent interactions in the aggregation and interaction patterns of biological molecules. The structures of the salts of the Z and E isomers of butenedioic acid (maleic and fumaric acid, respectively) with quinolin‐8‐ol are compared. 相似文献
5.
From the measurements of conductivity, diffusion coefficient etc., Jander indicated the presence of several isopoly-anions of molybdenum under different pH conditions. He and subsequent workers in the field dealt with solutions only. In the present work one free molybdic acid, and one ammonium acid molybdate were isolated in solid condition at pH 4.6 and 2. On analysis, their compositions were found to be H4Mo3O11 and NH4H5Mo6O21 (or (NH4)2H4Mo7O24) respectively. 相似文献
6.
Imidazole base was crystallized with different aromatic carboxylic acids 2,4-dihydroxybenzoic acid, 5-chlorosalicylic acid, and 1,8-naphthalic acid, affording three new binary molecular organic salts of [(C 3 H 5 N 2 + )·(C 7 H 5 O 4 )] (1), [(C 3 H 5 N 2 + )·(C 7 H 4 O 3 Cl )] C 7 H 5 O 3 Cl (2), and [(C 3 H 5 N 2 + ) (C 12 H 7 O 4 )] (3). Proton transfer occurs from the COOH of carboxylic acid to nitrogen of imidazole in all complexes (1-3), leading to the hydrogen bond N-H…O in all structures. To our knowledge, the recognition pattern between the carboxylic acid group and imidazole (acid-imidazole synthon) is less well-studied so far. The cooperation among COOH, COO and imidazolium cation functional groups for the observed hydrogen bond synthons is examined in the three structures. Generally, the strong N-H…O and O-H…O hydrogen bonds define supramolecular architecture and connectivity within chains, while weaker C-H…O hydrogen bonds play the dominant role in controlling the interactions between layers in these novel organic salts. Thermal stability of these compounds has been investigated by thermogravimetric analysis (TGA) of mass loss. 相似文献
7.
S‐((Phenylsulfonyl)difluoromethyl)thiophenium Salts: Carbon‐Selective Electrophilic Difluoromethylation of β‐Ketoesters, β‐Diketones,and Dicyanoalkylidenes
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Xin Wang Guokai Liu Dr. Xiu‐Hua Xu Naoyuki Shibata Etsuko Tokunaga Prof. Dr. Norio Shibata 《Angewandte Chemie (International ed. in English)》2014,53(7):1827-1831
S‐((Phenylsulfonyl)difluoromethyl)thiophenium salts were designed and prepared by a triflic acid catalyzed intramolecular cyclization of ortho‐ethynyl aryldifluoromethyl sulfanes. The thiophenium salts were found to be efficient as electrophilic difluoromehtylating reagents for introduction of a CF2H group to sp3‐hybridized carbon nucleophiles such as of β‐ketoesters and dicyanoalkylidenes. The (phenylsulfonyl)difluoromethyl group can be readily transformed into CF2H under mild reaction conditions. Enantioselective electrophilic difluoromethylation was also achieved in the presence of bis(cinchona) alkaloids. 相似文献
8.
S. Zouad J. Jeanjean C. Loos-Neskovic M. Fedoroff Y. Piffard 《Journal of Radioanalytical and Nuclear Chemistry》1994,182(2):193-204
The sorption of strontium and lanthanum on antimonic acid (HAP) and on two phosphatoantimonic acids, H3Sb3O6(PO4)2 (RH3) and H5Sb5O12(PO4)2 (RH5) were studied by three types of measurements: kinetics of fixation, distribution coefficients at trace level and sorption capacity. A 2H+/Sr2+ or 3H+/La3+ exchange stoichiometry and an affinity order of HAP>RH5>RH3 for Sr and RH3>HAP>RH5 for La were observed. The fixation kinetics is very fast for RH3. For HAP and RH5, there is a fast step followed by a slow diffusion-controlled step. The results are interpreted by comparing the chemical compositions and crystal structures of the three sorbents. Applications to radioactive waste treatment are discussed. 相似文献
9.
Xin Wang Guokai Liu Xiu‐Hua Xu Naoyuki Shibata Etsuko Tokunaga Norio Shibata 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2014,126(7):1858-1862
S‐((Phenylsulfonyl)difluoromethyl)thiophenium salts were designed and prepared by a triflic acid catalyzed intramolecular cyclization of ortho‐ethynyl aryldifluoromethyl sulfanes. The thiophenium salts were found to be efficient as electrophilic difluoromehtylating reagents for introduction of a CF2H group to sp3‐hybridized carbon nucleophiles such as of β‐ketoesters and dicyanoalkylidenes. The (phenylsulfonyl)difluoromethyl group can be readily transformed into CF2H under mild reaction conditions. Enantioselective electrophilic difluoromethylation was also achieved in the presence of bis(cinchona) alkaloids. 相似文献
10.
M. M. Charyulu D. G. Phal D. M. Noronha V. V. Ramakrishna V. Venugopal 《Journal of Radioanalytical and Nuclear Chemistry》2001,247(3):553-555
The extraction of Am(III) from nitric, hydrochloric, oxalic, phosphoric and hydrofluoric acids was studied using 0.4F di-2-ethyl hexyl phosphoric acid (HDEHP) containing 0.1M phosphorous pentoxide (P2O5) in dodecane/xylene. The extraction with pure 0.4F HDEHP was found to be negligible from all the media studied. However, the presence of a small amount of P2O5 in it increased the extraction substantially. The distribution ratios of Am(III) obtained for HDEHP - P2O5 mixture 3M nitric acid containing different concentrations of oxalic acid/phosphoric acid/hydrofluoric acid are in the order of 200-250. The same for 3M hydrochloric acid is very high (800). These distribution ratios are sufficiently high for the quantitative extraction of Am(III) from all the acid media studied. Different reagents such as ammonium oxalate, sodium oxalate, oxalic acid, hydrofluoric acid, sodium carbonate and potassium sulphate were explored for the back extraction of Am(III) from 0.4F HDEHP + 0.1M P2O5 in dodecane/xylene. Of these, 0.35M ammonium oxalate and 1M sodium carbonate were found to be most suitable. The back extraction of Am(III) was also attempted with water and 1M H2SO4, HNO3, HClO4 and HCl solutions after allowing the extracted organics to degrade on its own. It was found that more than 90% of Am could be back extracted with these acids. Using this method more than 90% of Am(III) was recovered from nitric acid solutions containing calcium and fluoride ions. 相似文献
11.
《Acta Crystallographica. Section C, Structural Chemistry》2018,74(5):571-583
Adenosine diphosphate (ADP) plays a crucial role in cell biochemistry, especially in metabolic pathways and energy storage. ADP itself, as well as many of its analogues, such as adenosine hypodiphosphate (AhDP), has been studied extensively, in particular in terms of enzymatic activity. However, structural studies in the solid state, especially for AhDP, are still missing. An analogue of ADP, i.e. adenosine hypodiphosphate ester, has been synthesized and characterized in the crystalline form as two hydrated sodium salts of 2′:3′‐isopropylideneadenosine 5′‐hypodiphosphate (H3AhDP, C13H19N5O9P2 for the neutral form), namely pentasodium tetrakis(2′:3′‐isopropylideneadenosine 5′‐hypodiphosphate) tetracosahydrate, 5Na+·3C13H18N5O9P2−·C13H17N5O9P22−·24H2O or Na5(H2AhDP)3(HAhDP)·24H2O, (I), and sodium tetrakis(2′:3′‐isopropylideneadenosine 5′‐hypodiphosphate) pentadecahydrate, Na+·C13H20N5O9P2+·2C13H18N5O9P2−·C13H19N5O9P2·15H2O or Na(H4AhDP)(H3AhDP)(H2AhDP)2·15H2O, (II). Crystal structure analyses of (I) and (II) reveal two nucleoside hypodiphosphate ions in the asymmetric units with different ionization states of the hypodiphosphate unit and adenine base. For all AhDP nucleotides, the same anti conformation about the N‐glycosidic bond and similar puckering of the ribose ring have been found. AhDP geometry and interactions have been compared to ADP nucleotides deposited in the Cambridge Structural Database. The adenine–hypodiphosphate interactions, identified as defining nucleotide self‐assembly, have been analysed in model systems, i.e. the adenine (Ade) salts of hypodiphosphoric acid, namely bis(adeninium) hypodiphosphate dihydrate, 2C5H6N5+·H2P2O62−·2H2O or (AdeH)2(H2P2O6)·2H2O, (III), and bis(adeninium) hypodiphosphate, 2C5H6N5+·H2P2O62− or (AdeH)2(H2P2O6), (IV). 相似文献
12.
Phosphorus pentoxide supported on silica gel or alumina (P2O5/SiO2, P2O5/Al2O3) has been used in many organic transformations as versatile solid catalysts. These catalysts have received considerable attention as an inexpensive, eco-friendly, highly reactive, easy to handle and non-toxic acid catalyst for various organic transformations, affording the corresponding products in excellent yields and high selectivity. In this review, some applications of these catalysts in organic reactions are discussed. 相似文献
13.
S Steenken 《Photochemistry and photobiology》1975,22(5):157-161
Abstract— –On in situ photolysis (Λ= 250–400 nm) of aqueous oxaloacetic acid solutions, between pH 5 and 10, the radicals -O2CCH2C(O->=C(O+)CH2CO2- and -O2CCH2C(OH)CO2 are identified. With acetone present, CH2CO2, CH3C(OH)CO-2, CH3C(O-)=C(O)CH2CO2 and -O2CCHCOCO2 are also observed. CO2 and CO are identified as reaction products. The experimental results are explained in terms of α-cleavage of the electronically excited keto-isomer dianion of oxaloacetic acid to yield O2CCH2CO and CO2-. -O2CCH2CO adds to the keto-isomer of oxaloacetic acid and to pyruvic acid, which is formed from oxaloacetic acid by thermal decarboxylation, to yield -O2CCH2C(O-)= C(O-)CH2C0- and CH3C(O-)=C(O)CH2CO-2, respectively, via a decarboxylase substitution reaction. CH2CO2 is derived from -O2CCH2CO by decarbonylation. CO2- is scavenged by oxaloacetic acid and pyruvic acid to yield O2CCH2C(OH)CO2 and CH3C(OH)CO2-, respectively. 相似文献
14.
E. A. Prodan S. I. Pytlev T. N. Galkova V. A. Sotnikova-yuzhik L. I. Patrovskaya 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1-4)
Abstract The polycrystalline samples and single crystals of crystal hydrates of inorganic triphosphates with ring-like and chain-like anion structured were synthesized: lithium and sodium cyclotriphosphates, sodium and ammonium chain triphosphates, and double salts of chain triphosphoric acid (ammonium-potassium, ammonium-magnesium, ammonium-manganese). The crystallization field of the double salt of variable composition (NH4,K)3H2P3O10 ·xH2O (NH4 :K=0.23–3.60; x=0.8–1.5) from aqueous solutions was established. Synthesis of Na5P3O10 · 6D2O crystals has been performed by the interaction of the high temperature form Na5P3O10 (I) with D20. At 20°C and relative humidity RH < 70–80% the (NH4) 5P3O10·2H2O crystals lose their transparency and generate different crystalline products depending on RH value: (NH4)5P3O10 at RH=0% or (NH4)5P3 10 · H2O at RH=32%. The (NH4) 5P3 O10 · H2O crystals are stable at RH < 60–70%, at RH=80% they absorb water and transform into (NH4) 5P3O10 · 2H20. In the latter case a characteristic picture is registered: on active sites situated on the (NH4) 5P3O10 · H2O crystal face the appearance and epitaxial growth of (NH4) 5P3O10 · H2O crystals is observed. For some single crystals the character of dehydration localization has been shown to correlate with space arrangement of phosphate groups in crystal structure. On the basis of the obtained results a model of dehydration front propagation in crystals has been suggested. 相似文献
15.
Reactions of dimethyl(dimethylsulphoxide)pentamethylcyclopentadienyl-rhodium and -irridum with acids
Manuel Gómez Paul I.W. Yarrow Amelio Vázquez De Miguel Peter M. Maitlis 《Journal of organometallic chemistry》1983,259(2):237-243
The complexes [C5Me5MMe2(Me2SO)] (Ia, M = Rh; Ib, M = Ir) react with p-toluenesulphonic acid in acetonitrile to give [C5Me5MMe(Me2SO)(MeCN)]+, (II), and with trifluoroacetic acid to give first [C5Me5MMe(Me2SO)(O2CCF3)] and then [C5Me5M(Me2SO)(O2CCF3)2]. Complexes II react with halide (X?) to give the halomethyl complexes [C5Me5MMe(X)(Me2SO)]. The IR, far-IR, 1H and 13C NMR spectra are all in agreement with structures proposed. 相似文献
16.
Abdol. R. Hajipour Amin Zarei Leila Khazdooz Seied A. Pourmousavi Bi Bi F. Mirjalili A. E. Ruoho 《Phosphorus, sulfur, and silicon and the related elements》2013,188(9):2029-2034
Direct sulfonylation of aromatic rings with aryl or alkyl sulfonic acid supported P2O5/Al2O3 (w/w 50%) under heterogeneous conditions in short reaction time and high yields. 相似文献
17.
《International journal of mass spectrometry and ion processes》1998,172(1-2):137-147
We report the results of a selected ion flow tube (SIFT) study of the reactions of H3O+, NO+ and O+2 with some nine carboxylic acids and eight esters. We assume that all the exothermic proton transfer reactions of H3O+ with all the acid and esters molecules occur at the collisional rate, i.e. the rate coefficients, k, are equal to kc; then it is seen that k values for most of the NO+ and O+2 reactions also are equal to or close to kc. The major ionic products of the H3O+ reactions with both the acids and esters are the protonated parent molecules, MH+, but minor channels are also evident, these being the result of H2O elimination from the excited (MH+)1 in some of the acid reactions and an alcohol molecule elimination (CH3OH or C2H5OH) in some of the ester reactions. The NO+ reactions with the acids and esters result in both ion-molecule association producing NO+M in parallel with hydroxide ion (OH−) transfer with some of the acids, and parallel methoxide ion (CH3O−) and ethoxide ion (C2H5O−) transfer as appropriate with some of the esters. The O+2 reactions proceed by dissociative charge transfer with the production of two or more ionic fragments of the parent molecules, the different isomeric forms of both the acid and the ester molecules resulting in different product ions. 相似文献
18.
Noriyuki Yonezawa Tetsuo Hino Tsuyoshi Kinuno Toshiyuki Matsuki Tomiki Ikeda 《合成通讯》2013,43(10):1687-1695
Pyruvic acid (3) was found to be arylated chemoselectively at the a-ketocarbonyl carbon in P2O5-MsOH affording decarbonylative α,α-diarylated products 5, decarbonylative a-monoarylated compounds 6, or non-decarbonylative α,α-diarylated adducts 7 depending on the reactivity of arenes (4a-g), in contrast to Lewis acid-catalyzed reaction of its acid chloride (2). 相似文献
19.
Preparation and Investigation of Difluoromethyl-substituted Amines N-Methyl- ( 6a ), N-ethyl-bis(difluoromethyl)-amine ( 6b ), and tris(difluoromethyl)-amine ( 7 ) were prepared by fluorination of the corresponding chloro compounds ( 2a , 2b , 5 ) with antimony(III) fluoride. The reaction of N-methyldiformamide ( 1a ) with carbonylfluoride led under special conditions to the already unknown α,α-difluorodimethylformamide ( 8 ). 6a , 6b , and 7 were proven to be molecules with covalent carbon-fluorine bonds. By reaction of 6a with antimony(V) or boron(III) fluoride a fluoride ion could be split off from a difluoromethyl group. The vibrational spectrum of 7 was assigned and supported to a plane configuration of the NC3 skeleton and C3h molecular symmetry. 相似文献
20.
Song Hu Wang Yunhan Wang Jing Wang Guanquan He Jiaheng Wei Hongyuan Luo Shunzhong 《Journal of Radioanalytical and Nuclear Chemistry》2018,317(2):685-699
Uranium sorption from commercial phosphoric acid was carried out onto kaolinite and metakaolinite. The different factors affecting uranium adsorption have been investigated. The obtained results show that, the sorption process is applicable for the high strength phosphoric acid, 40% P2O5, and diluted phosphoric acid, 20% P2O5, but it preferred to the diluted phosphoric acid. The kinetic models applied to the sorption rate data were evaluated for Lagergren first order and the pseudo second order models. From the results, the uranium sorption from commercial phosphoric acid, 40% P2O5, onto kaolinite and metakaolinite was found to occur through physical sorption process. 相似文献