共查询到20条相似文献,搜索用时 31 毫秒
1.
《催化学报》2015,(8)
This paper reviews the recent achievements in the immobilization of metal nanoparticles on ion-exchange resins and the related catalytic application. The focus is on the production processes for fine and commodity chemicals for which a low environmental impact has been demonstrated. The most significant papers that appeared in the literature from January 2010 to July 2014 have been covered. Their uses in unselective processes, bulk chemicals production, fuel cells components, as well as the use of metal-free ion-exchange resins in acid / base-catalysed reactions, were not included. 相似文献
2.
This paper reviews the recent achievements in the immobilization of metal nanoparticles on ion-exchange resins and the related catalytic application. The focus is on the production processes for fine and commodity chemicals for which a low environmental impact has been demonstrated. The most significant papers that appeared in the literature from January 2010 to July 2014 have been covered. Their uses in unselective processes, bulk chemicals production, fuel cells compo-nents, as well as the use of metal-free ion-exchange resins in acid/base-catalysed reactions, were not included. 相似文献
3.
Possible causes of the occurrence of radioactive contamination irremovable by acid–base regeneration of ion-exchange resins used in treatment of process media and liquid radioactive waste have been studied. It has been found that most of the irremovable cesium radionuclides are bound to inorganic deposits on the surface and in the bulk of ion-exchange resin granules. The nature of inorganic inclusions has been investigated on real and model spent ion-exchange resins (SIER). A method has been proposed for decontaminating SIER using resorcinol–formaldehyde resins selective to cesium radionuclides. Such an approach has been shown to be promising for deep decontamination of SIER. 相似文献
4.
The uricase-like catalytic activity of the ion-exchange resins modified with metalloporphyrins has been investigated through the oxidation of uric acid. The anion-exchange resins modified with Mn(3+)-tetrakis(sulfophenyl)porphine and the cation-exchange resin modified with Mn(3+)-tetrakis(1-methylpyridinium-4-yl)porphine exhibited the highest uricase-like activity among the modified resins tested. The fact that these resins accelerated the oxidation of uric acid even after ten cycles of use indicates that the modified resins act as catalysts in the reaction catalysed by uricase. Some of the modified resins may be effectively used for the determination of uric acid in place of uricase. 相似文献
5.
The esterification of 3,5-di-tert-butyl-4-hydroxybenzoic acid with 1-hexadecanol over a series of ion-exchange resins was investigated, in which resin D072 exhibited excellent catalytic performance. The influence of water on the reaction was also investigated, and it was found that water could improve the selectivity and increase the yield of the target product. Treatment of resins with aqueous sodium hydroxide could improve the selectivity of the target product but remarkably decreased the conversion of 3,5-di-tert-butyl-4-hydroxybenzoic acid. This result indicated that strong Brønsted acid sites played an important role in the reaction. Furthermore, D072 was efficiently recycled four runs by simple treatment with mineral acid. Finally, a series of hindered phenolic esters were successfully synthesized under the optimal reaction conditions. Therefore, a simple and versatile method for the synthesis of hindered phenolic esters has been established over ion-exchange resins and the target products were obtained in good yields. 相似文献
6.
The reaction of glycerol with tert-butyl alcohol in the liquid phase on acid Amberlyst-type ion-exchange resins was studied. The influence of temperature, mole
ratio n(TBA)/n(G), water and swelling of gel, and macroreticular type of polymer catalysts on etherification reaction was investigated.
The most favourable reaction temperature is 75°C. The conversion of glycerol and yield of glycerol tert-butyl ethers has increased with the mole ratio n(TBA)/n(G). Dry form of macroreticular catalysts provided the best results. Etherification reaction of glycerol with isobutylene
in non-aqueous conditions gives the highest yield of desired ethers. The influence of water was studied. The gel forms of
ion-exchange resins have very low catalytic activity. It can be concluded that water has an inhibition effect on ion-exchange
resins. By comparing the gel and macroreticular forms of Amberlyst ion-exchange resins it can be concluded that very acid
forms of macroreticular ion-exchange resins with a high degree of crosslinking are more active catalysts for the studied reaction
due to their pores which are sufficiently large so that the voluminous tert-butyl ethers of glycerol can be formed. It was estimated that tert-butyl alcohol as tert-butylation agent is not suitable for etherification of glycerol with the formation of di-and triethers. 相似文献
7.
AnHua Liu LiangNian He ShiYong Peng ZhongDa Pan JingLun Wang Jian Gao 《中国科学:化学(英文版)》2010,53(7):1578-1585
Basic ion-exchange resins, one kind of polystyryl-supported tertiary amine, were demonstrated to be highly efficient and recyclable catalysts for the fixation of carbon dioxide with aziridines under mild conditions, leading to the formation of 5-aryl-2-oxazolidinone with excellent regio-selectivities. Notably, neither solvents nor any additives were required, and the catalyst could be recovered by simple filtration and directly reused at least five times without significant loss of catalytic activity and selectivity. The present protocol has been applied to reactions of epoxides/propargyl amines with CO2/CS2. This solvent-free process thus represents environmentally friendly catalytic conversion of CO2 into value-added chemicals and may have potential in various continuous flow reactors in industry. 相似文献
8.
The local structures of Cl- and Br- in anion-exchange resins have been studied by X-ray absorption fine structure (XAFS), and separation selectivity is discussed on the basis of results. When two different anion-exchange resins having trimethylammonium and dimethylammonium groups as anion-exchange groups are employed for ion-exchange experiments, slightly higher Br- selectivity has been obtained with the former. XAFS has indicated that the average hydration numbers for a given anion is not affected by the structure of the ion-exchange group, but that the extent of ion-association between the anion and the ion-exchange groups depends on the type of the ion-exchange group. Shorter interaction distance (and in turn stronger ion-association) has been confirmed for the dimethylammonium-type resin, and is consistent with lower Br- selectivity of this resin. 相似文献
9.
Cylindrical pellets were made by mixing ion-exchange resin particles with binding powders and heating to 140°C. To compare catalytic activities of these resin pellets with those of resin particles and sulfuric acid, the esterification of palmitic acid with isobutyl alcohol was carried out in a batch reactor. The rate equation for sulfuric acid could be applied to ion-exchange resins although the values of parameters were different. 相似文献
10.
Å. Magnusson K. Stenström P. -O. Aronsson 《Journal of Radioanalytical and Nuclear Chemistry》2008,275(2):261-273
A method of separately quantifying organic and inorganic 14C compounds present in spent ion-exchange resins and process water from nuclear power reactors has been developed. Extraction
of carbon compounds is accomplished by means of acid stripping (inorganic 14C) and subsequent wet oxidation (organic 14C) or by N2 purging in combination with a catalytic furnace (oxidized and reduced gaseous compounds) with organic and inorganic 14C species collected separately. Recovery experiments on simulated samples spiked with 14C-labeled sodium carbonate, sodium acetate and sodium formate, showed extraction yields of 94–98%. The sample-specific procedures
were also tested on authentic samples of spent resins and reactor water with good results. Validation and reliability of the
procedures are presented and the method is compared to previous methods reported in the literature. 相似文献
11.
Tagusagawa C Takagaki A Hayashi S Domen K 《Journal of the American Chemical Society》2008,130(23):7230-7231
Layered HNbMoO6 was found to function as a strong solid acid catalyst, exceeding the activity of zeolites and ion-exchange resins for Friedel-Crafts alkylation. HNbMoO6 also exhibited high catalytic activity for esterification of hydrocarboxylic acid and hydration. The catalytic performance of layered HNbMoO6 is attributed to the intercalation of reactants into the interlayer and the development of strong acidity. 相似文献
12.
A series of ion-exchange resins containing -COCH(2)N[(CH(2))(m)COOH(2)](2) groups has been synthesized. Additional analogues were prepared by means of the reaction of the carbonyl group with phosphorus trichloride or thioglycollic acid. The properties of these resins and the selectivity for different metal ions have also been investigated. 相似文献
13.
A stable electroactive thin film of poly(4,5-dihydroxy-1,3-benzenedisulfonic acid) was electrochemically deposited at the surface of multiwall carbon nanotubes-glassy carbon electrode. The electrocatalytic oxidation of hydrazine has been studied at the surface of the modified electrode using cyclic voltammetry, chronoamperometry and linear sweep voltammetry as diagnostic techniques. The modified electrode exhibits good electrocatalytic activity for the oxidation of hydrazine with a good sensitivity. Linear calibration range was in the wide concentration range of 10–3540 μM hydrazine with a detection limit of 1.8 μM and a sensitivity of 85.3 nA/μM. A Tafel plot, derived from voltammograms, indicated a one-electron transfer process to be the rate-limiting step and the overall number of electrons involved in the catalytic oxidation of hydrazine was found to be four. The influences of potentially interfering substances were studied. The diffusion coefficient of hydrazine was also evaluated. Finally, the proposed modified electrode was used for the determination of hydrazine in spiked water samples. 相似文献
14.
15.
Li Q Li WL Wang D Liu BB Tang H Yang MH Liu QF Xing JM Su ZG 《Applied biochemistry and biotechnology》2010,160(2):438-445
Succinic acid is a useful chemical and its purification from fermentation broth by ion-exchange resins has widely drawn attention.
In this study, pH neutralization in the process of adsorption of succinic acid from model solutions and fermentation broth
by anion-exchange resin NERCB 04 has been tested. Adsorption capacity of NERCB 04 was about 0.41 g succinic acid/g resin at
concentrations of succinic acid in the range of 10–50 g/L in packed column. In the process of succinic acid removal, pH of
the system could also be neutralized. The neutralizing ability of the resin as a neutralizing agent has also been studied
in the model cycle system and in the real fermentation cycle process. It was found that NERCB 04 showed stable adsorption
capacity and pH neutralization ability after each regeneration. A certain amount of anion-exchange resin could neutralize
the low pH values (pH 2–5) and maintain the system around pH 7.0. This means the anion-exchange resins have the function of
neutralizing reagent in the process of adsorbing succinic acid. 相似文献
16.
Most important properties of an ion chromatographic resin are influenced by the resin matrix, the type of functional group and the ion-exchange capacity. Highly crosslinked PS-DVB resins of 5 microm diameter have been functionalized by sulfoacylation, by sulfonation and by dynamic coating over a wide range of exchange capacities. These materials allow a study of the influence of different ion-exchange sites and capacities. The influence of the degree of functionalization on resin performance is completely reverse for sulfoacylated and sulfonated resins. The HETP values for all observed analytes (Cu, Pb, Zn, Ni, Co, Cd, Mn, Ca, Mg) in a tartaric acid elution system decrease for sulfoacylated resins with increasing capacity, for sulfonated resins with decreasing capacity. The performance of sulfoacylated exchangers is better than for dynamically coated ones and far better than for sulfonated resins. The performance of silica gel based cation-exchangers such as BioSil CAT is in most cases better than observed for sulfoacylated resins. 相似文献
17.
Justin Y. Wang Kyoungmin Choi Stephan J. Zuend Kailaskumar Borate Harish Shinde Roland Goetz John F. Hartwig 《Angewandte Chemie (International ed. in English)》2021,60(1):399-408
Reported here is the Pd‐catalyzed C–N coupling of hydrazine with (hetero)aryl chlorides and bromides to form aryl hydrazines with catalyst loadings as low as 100 ppm of Pd and KOH as base. Mechanistic studies revealed two catalyst resting states: an arylpalladium(II) hydroxide and arylpalladium(II) chloride. These compounds are present in two interconnected catalytic cycles and react with hydrazine and base or hydrazine alone to give the product. The selectivity of the hydroxide complex with hydrazine to form aryl over diaryl hydrazine was lower than that of the chloride complex, as well as the catalytic reaction. In contrast, the selectivity of the chloride complex closely matched that of the catalytic reaction, indicating that the aryl hydrazine is derived from this complex. Kinetic studies showed that the coupling process occurs by rate‐limiting deprotonation of a hydrazine‐bound arylpalladium(II) chloride complex to give an arylpalladium(II) hydrazido complex. 相似文献
18.
M. T. Turakhozhaev L. P. Zubkova M. -R. I. Shamsutdinov G. L. Genkina T. T. Shakirov 《Chemistry of Natural Compounds》1974,8(1):74-76
Summary 1. The possibility of using ion-exchange resins for the purification of extracts in the isolation of cardiac glycosides has been shown.2. A method is proposed for obtaining olitoriside by using a mixture of anion-exchange and cation-exchange resins to purify the extract, this method giving an increased yield of the preparation.Translated from Khimiya Prirodnykh Soedinenii, No. 1, pp. 81–83, January–February, 1972. 相似文献
19.
Masao Tomoi Yasunori Hosokawa Hiroshi Kakiuchi 《Journal of polymer science. Part A, Polymer chemistry》1984,22(6):1243-1250
The rate of reaction of alkyl halides with aqueous sodium acetate or cyanide catalyzed by phosphonium salts supported on insoluble polystyrene resins, and rates of ion-exchange of the chloride ion in the catalysts against the acetate ion, were studied as a function of catalyst particle size, the percentage of ring substitution, the morphology of polymer support, and distance between active site and polymer backbone. Rates of 1-bromooctane or benzyl chloride with macroporous, 7–25% ring-substituted catalysts increased with increasing ring substitution. Rates with macroporous catalysts increased as a heptamethylene spacer was introduced between the active site and the polymer backbone. Rates of ion-exchange with macroporous catalysts were facilitated with increasing ring substitution or by the introduction of the spacer chain. A relation between the catalytic activity of macroporous or microporous catalysts and ion-exchange rates under triphase conditions was discussed. 相似文献
20.
Summary As the result of a purification process consisting of precipitation and successive stages of chromatography on ion-exchange resins, electrophoretically homogeneous rat transferrin has been obtained with a molecular weight of 76,500 daltons, a maximum in the absorption spectrum at 465 nm, and isoelectric points of the two isoforms of 6.0 and 6.3.Institute of Bioorganic Chemistry, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 5, pp. 609–612, September–October, 1978. 相似文献