Macroreticular p-(ω-sulfonic-perfluoroalkylated) polystyrene ion-exchange resins: a new type of selective solid acid catalyst

2005 ◽  
pp. 3556 ◽  
Author(s):  
Zhenghuan Lin ◽  
Chengxue Zhao
Keyword(s):  
Ion Exchange ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Ion Exchange Resins ◽  
New Type ◽  
Exchange Resins

ESTERIFICATION OF RENEWABLE LEVULINIC ACID TO LEVULINATE ESTERS USING AMBERLYST-15 AS A SOLID ACID CATALYST

2016 ◽  
Vol 79 (1) ◽  
Author(s):  
Nur Aainaa Syahirah Ramli ◽  
Nur Hidayah Zaharudin ◽  
Nor Aishah Saidina Amin
Keyword(s):  
Levulinic Acid ◽  
Solid Acid ◽  
Solid Acid Catalyst ◽  
Acid Catalyst ◽  
Molar Ratio ◽  
Catalyst Loading ◽  
Process Conditions ◽  
Amberlyst 15 ◽  
Methyl Levulinate ◽  
Exchange Resins

Levulinic acid (LA) is a versatile biomass-derived building block as it can be used for the synthesis of organic chemicals as alternative to the depleting fossil fuel resources. Levulinate esters, obtained from catalytic esterification of LA with alcohol, can be used in many applications such as fragrance and fuel additives. In this study, ion-exchange resins Amberlyst-15 was employed as solid acid catalyst for esterification of LA with methanol for methyl levulinate (ML) production. The effect of reaction time, catalyst loading, and molar ratio of LA to methanol, was investigated on LA esterification to ML at the reflux condition. The optimum ML yield of 82% was obtained from reaction conducted at reflux temperature for 5h, using 30% of Amberlyst-15 loading, and 1:20 of LA to methanol molar ratio. The reusability of Amberlyst-15 for ML production was examined for five successive reactions. In addition, Amberlyst-15 catalyst, employed in the esterification of LA with ethanol and 1-butanol for ethyl levulinate (EL) and butyl levulinate (BL), respectively, registered good performance. Yields of 71% and 55% have been obtained for EL and BL, respectively. Amberlyst-15 is a promising solid acid catalyst for production of biomass derived levulinate esters at mild process conditions. 

Embedding Procedure for Water Swollen Samples

1970 ◽  
Vol 28 ◽  
pp. 504-505
Author(s):  
Ann M. Thomas ◽  
Virginia Shemeley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Exchange ◽  
Structural Changes ◽  
Cross Linking ◽  
Ion Exchange Resins ◽  
Transmission Electron ◽  
First Pass ◽  
Exchange Resins

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.

Applications of Ion Exchange Resin in Oral Drug Delivery Systems

2017 ◽  
Vol 7 (03) ◽  
Author(s):  
Kathpalia Harsha ◽  
Das Sukanya
Keyword(s):  
Drug Delivery ◽  
Ion Exchange ◽  
Drug Delivery Systems ◽  
Oral Drug Delivery ◽  
Physical Stability ◽  
Delivery Systems ◽  
Oral Drug ◽  
Ion Exchange Resins ◽  
Exchange Resins ◽  
Oral Drug Delivery Systems

Ion Exchange Resins (IER) are insoluble polymers having styrene divinylbenzene copolymer backbone that contain acidic or basic functional groups and have the ability to exchange counter ions with the surrounding aqueous solutions. From the past many years they have been widely used for purification and softening of water and in chromatographic columns, however recently their use in pharmaceutical industry has gained considerable importance. Due to the physical stability and inert nature of the resins, they can be used as a versatile vehicle to design several modified release dosage forms The ionizable drug is complexed with the resin owing to the property of ion exchange. This resin complex dissociatesin vivo to release the drug. Based on the dissociation strength of the drug from the drug resin complex, various release patterns can be achieved. Many formulation glitches can be circumvented using ion exchange resins such as bitter taste and deliquescence. These resins also aid in enhancing disintegrationand stability of formulation. This review focuses on different types of ion exchange resins, their preparation methods, chemistry, properties, incompatibilities and their application in various oral drug delivery systems as well as highlighting their use as therapeutic agents.

THE DISPOSAL OF USED ION EXCHANGE RESINS

2004 ◽  
Vol 3 (3) ◽  
pp. 447-455
Author(s):  
Viky Dicu ◽  
Carmen Iesan ◽  
Mihai Chirica ◽  
Satish Bapat
Keyword(s):  
Ion Exchange ◽  
Ion Exchange Resins ◽  
Exchange Resins
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