Macroreticular

Bio-Rex 70 2.4 0.70 Weakly acidic cation exchanger with car-boxylate groups on a macroreticular acrylic matrix for separation and fractionation of proteins, peptides, enzymes, and amines, particularly high molecular weight solutes. Does not denature proteins as do styrene-based resins. 

Anion exchanger- —macroreticular type—strongly basic —quaternary ammonium functionality... 

Cation exchange resin— -macroreticular type- — sulfonic acid functionality... 

Weak cation exchanger—macroreticular type—carboxylic acid or phenolic functionality... 

Macroporous resins are also called macroreticular. Macroporous resins have a measurable porosity. It does not disappear when the resin is dry. Porosity is more dependent on the solvent used when manufacturing the copolymer than on the degree of cross-linking. 

W. W. Schulz, Macroreticular Anion Exchange Resin Cleanup for TBP Solvents, ARH-SA-129, Adantic Richfield Hanford Co., Richland, Wash., 1972. 

Esterification. Extensive commercial use is made of primary amyl acetate, a mixture of 1-pentyl acetate [28-63-7] and 2-metliylbutyl acetate [53496-15-4]. Esterifications with acetic acid are generally conducted in the Hquid phase in the presence of a strong acid catalyst such as sulfuric acid (34). Increased reaction rates are reported when esterifications are carried out in the presence of heteropoly acids supported on macroreticular cation-exchange resins (35) and 2eohte (36) catalysts in a heterogeneous process. Judging from the many patents issued in recent years, there appears to be considerable effort underway to find an appropriate soHd catalyst for a reactive distillation esterification process to avoid the product removal difficulties of the conventional process. 

Resin adsorbents (macroreticular polymer resins) generally good for removal of up to 1—2% of stream (often regenerable). 

Truly porous, synthetic ion exchangers are also available. These materials retain their porosity even after removal of the solvent and have measurable surface areas and pore size. The term macroreticular is commonly used for resins prepared from a phase separation technique, where the polymer matrix is prepared with the addition of a hq-uid that is a good solvent for the monomers, but in which the polymer is insoluble. Matrices prepared in this way usually have the appearance of a conglomerate of gel-type microspheres held together to... 

Reillex 425-HCl, dihydropyran, 86°, 1.5 h, 84-98% yield. The Reillex resin is a macroreticular polyvinylpyridine resin and is thus an insoluble form of the PPTS catalyst. 

The relation between the amount of catalyst and the efficiency of a new macroreticular sulfonated acrylonitrile... 

J mol ). This is additional evidence in favor of rate limitation by inner diffusion. However, the same reaction in the presence of Dowex-50, which has a more open three-dimensional network, gave an activation energy of 44800 J mol , and closely similar values were obtained for the hydrolysis of ethyl acetate [29] and dimethyl seb-acate [30]. The activation energy for the hydrolysis of ethyl acetate on a macroreticular sulphonated cationic exchanger [93] is 3566 J mol . For the hydrolysis of ethyl formate in a binary system, the isocomposition activation energy (Ec) [28,92] tends to decrease as the solvent content increases, while for solutions of the same dielectric constant, the iso-dielectric activation energy (Ed) increases as the dielectric constant of the solvent increases (Table 6). 

New Macroreticular Cationic Resins from Natural Products... 

Clearly the application of macroreticular (macroporous) ion exchange resins will be often advantageous in the separation of organic species. 

In contrast to the above resins, the chelating resin Amberlite IRC-718 is based upon a macroreticular matrix. It is claimed to exhibit superior physical durability and adsorption kinetics when compared to chelating resins derived from gel polymers and should also be superior for use in non-aqueous solvent systems. 

Fig. 3. Change in relative swelling coefficient Kw during ionization of macroreticular MA-EDMA copolymers obtained in 30% Ac A solution (1-4) and heteroreticular MA-EDMA copolymers obtained in 5% Ac A solution (5,6) with different amounts of the crosslinking agent — EDMA (mol%) /) 1.0 2) 1.5 3) 2.5 4) and 5) 4.0 6) 10.0...

Fig. 8. Titration curves of 1) macroreticular AA-EDMA (2.5 mol%) copolymer 2) linear PMA and S) macroreticular MA-EDMA (2.5 mol%) copolymer...

The possibility of conformational changes in chains between chemical junctions for weakly crosslinked CP in ionization is confirmed also by the investigation of the kinetic mobility of elements of the reticular structure by polarized luminescence [32, 33]. Polarized luminescence is used for the study of relaxation properties of structural elements with covalently bonded luminescent labels [44,45]. For a microdisperse form of a macroreticular MA-EDMA (2.5 mol% EDMA) copolymer (Fig. 9 a, curves 1 and 2), as compared to linear PM A, the inner structure of chain parts is more stable and the conformational transition is more distinct. A similar kind of dependence is also observed for a weakly crosslinked AA-EDMA (2.5 mol%) copolymer (Fig. 9b, curves 4 and 5). 

Tabelle 9. Values of AG and AG for cooperative bonding of proteins by an MA-EDMA (2.5 mol %) macroreticular copolymer in the variation of the degree of ionization of carboxylic groups... 

Yurchenko VS (1977) Physico-chemical Properties of Macroreticular Polyelectrolytes in Connection with Specific Features of Sorption of Organic Substances. (In Russian) Dissertation, Institute of Macromol Compounds, Acad Sci USSR, Leningrad... 

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