Laboratory-scale resin preparation

Measurement and Control Hardware for Laboratory-Scale Resin Preparations... 

Agitation for laboratory-scale resin preparation, drive systems, 441 Aqueous-phase mass balances, determination, 384-385 Arrhenius aaivatton parameters, calculation, 423,42 ... 

The following process is suitable for rapid laboratory-scale separation of cerium earths the cerium is removed from the mixture by precipitation with KMn04 and NagCOa (see below, preparation of pure Ce compounds). The remaining compounds are adsorbed on 250 ml. of a cation exchange resin (Dowex 50 or Wofatit KPS-200 particle size 0.2-0.4 mm.). The resin is then placed in an ion-exchange column (I.D. 4 cm.) which is partly filled with water. A second column of the same I.D. is filled in the same manner with 350 ml. of the resin in the Zn form. 

Acetalization and ketalization, like esterification, are also important candidate reactions for RD. It is a reversible reaction between aldehyde/ketone and alcohol that generates one molecule of water with one molecule of acetal/ketal. Various acetals, such as methylal and dioxalane, are useful solvents in the chemical industry. Ma-samuto and Matsuzaki (1994) first prepared methylal from formaldehyde and methanol in the presence of cation-exchange resins using a laboratory scale RD column conveniently packed in the form of tea-bag structures [31]. Kolah et al. studied this reaction in both batch and continuous RD column, as shown in Fig. 1.6, with a theoretical analysis of multiple reactions in the RD column [32]. Along with the acetal, formation of dimers and hemiacetals also takes place with substantial con-... 

In the preparation of UF resins, industrial-grade raw materials were used, provided by EuroResinas — Inddstrias Qufmicas S.A., Portugal, namely, urea, 50% formaUn, sodium hydroxide solution, and acetic acid solution. The synthesis was carried out in a laboratory-scale 51 glass reactor. 

Following the completion of the polymerization process, the beaded polymer is recovered from the suspension mixture and freed from the stabilizer, diluents, and traces of monomers and initiators. For laboratory and small-scale preparation, repeated washings with water, methanol, or acetone are appropriate. Complete removal of the monomer diluent, solvents, and initiator, especially from macroporous resin, may require a long equilibration time with warm methanol or acetone. In industry, this is usually accomplished by stream stripping. 

Polymer preparations should not be scaled up without a careful review and a gradual scaleup to check exotherms. This will determine the proper equipment and cooling needed before starting. All glassware should be free of cracks, and defects before using. In most cases, ordinary laboratory glassware may be used, but resin kettles are sometimes desirable on a larger scale operation. 

To date, only a few examples of laboratory preparative-scale processes based on purified enzyme have been reported. Several studies have focused on the small-scale implementation of processes associating a new co-factor regenerating system, enzyme immobilization, membrane reactor, continuous substrate feeding, or resin-based SFPR with various results [110], Using the outstanding stabihty of PAMO, a 200 ml biotransformation of 5g/l phenyl cyclohexanone by an engineered mutant under two-Hquid phase conditions using methyl tert-butyl ether as solvent was described [102]. 

Resins with cellulosic matrices are much more hydrophilic and these do not tend to denature proteins. Cellulosic resins have been used extensively in the laboratory analyses of biological materials, enzyme immobilizations and small scale preparations. The low capacity and poor flow characteristics have limited the usefulness of these matrices for larger applications. 

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